Investigating the Potential of Low Exergy Thermal Sources to

Investigating the Potential of Low Exergy Thermal Sources to
Investigating the Potential of Low
Exergy Thermal Sources to
Improve the COP of Heat Pumps
Author: Brian Gillan
Supervisor: Dr. Daniel Costola
A thesis submitted in partial fulfilment for the requirement of the degree:
Master of Science
Sustainable Engineering: Renewable Energy Systems & the Environment
2016
The place of useful learning
The University of Strathclyde is a charitable body, registered in Scotland, number SC015263
Copyright Declaration
This thesis is the result of the author’s original research. It has been composed by the
author and has not been previously submitted for examination which has led to the
award of a degree.
The copyright of this thesis belongs to the author under the terms of the United
Kingdom Copyright Acts as qualified by University of Strathclyde Regulation 3.50.
Due acknowledgement must always be made of the use of any material contained in,
or derived from, this thesis.
Signed: Brian Gillan
Date: 26/08/2016
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Abstract
The purpose of this dissertation was to investigate the potential of low exergy thermal
sources to improve the coefficient of performance of heat pumps, due to a global desire
to improve the efficiency of renewable technology and reduce energy consumption.
After reviewing existing literature, it was decided to focus on anthropogenic low exergy
thermal sources with air source heat pumps as there appeared to be a relative lack of
research in this area.
A number of air source heat pumps were analysed to determine if sensitivity to source
temperature changes was consistent across all selected manufacturers and models. It
was determined that there was a high degree of variation in sensitivity, with air-to-water
heat pumps being overall more sensitive than air-to-air heat pumps. It was also
determined that whilst some heat pumps were more sensitive in a low temperature
range, others were more sensitive in a medium temperature range. This finding
indicated that the climate within which it is operating will be a major factor when
choosing a heat pump to use.
Having selected a heat pump with an appropriate degree of sensitivity, schematics were
created indicating, showing theoretical configurations in which the heat pump could be
installed within a building. The relevant calculations were then performed to calculate
the potential COP improvements that could be achieved. It was found that by utilising
20°C indoor air, vented directly to an air mixer feeding the evaporator unit, and waste
heat from the compressor, a maximum COP increase of 23% could be achieved,
resulting in an energy saving of approximately 18%.
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Acknowledgements
I would like to thank my supervisor, Dr Daniel Costola, for his encouragement and
assistance throughout this project. The ability to bounce ideas off him at our weekly
meetings kept me on track and moving forward at a good pace.
I would also like to thank several of my former colleagues at ISS Facility Services in
Bishopton for their assistance in sourcing information and generally providing me
with their technical expertise when required.
I would like to thank all the lecturers from this Master’s course for providing me with
the knowledge and belief in myself to complete this dissertation.
Lastly I would like to thank my parents and friends for their continued support,
patience and encouragement throughout this last year and in particular whilst writing
this dissertation.
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Contents
Copyright Declaration .................................................................................................... 2
Abstract .......................................................................................................................... 3
Acknowledgements ........................................................................................................ 4
Nomenclature ................................................................................................................. 8
List of Figures ................................................................................................................ 9
List of Tables ............................................................................................................... 11
1. Introduction ........................................................................................................... 12
1.1.
Problem Definition ........................................................................................ 12
1.2.
Aim ................................................................................................................ 13
1.3.
Objectives ...................................................................................................... 13
1.4.
Outline of Methodology ................................................................................ 13
2. Literature Review .................................................................................................. 16
2.1.
Introduction ................................................................................................... 16
2.2.
Heat Pumps ................................................................................................... 17
2.2.1. Heat Pump Benefits ................................................................................... 17
2.2.2. Heat Pump Operation and The Carnot Cycle ............................................ 18
2.2.3. Coefficient of Performance (COP) ............................................................ 19
2.3.
Exergy ........................................................................................................... 21
2.4.
Using Natural Exergy Thermal Sources with Heat Pump Systems .............. 21
2.5.
Using Anthropogenic Exergy Thermal Sources with Heat Pump Systems .. 26
2.6.
Identifying Low Exergy Thermal Sources in Buildings ............................... 28
2.7.
Energy Savings from Building Upgrades ...................................................... 29
2.8.
Conclusions ................................................................................................... 30
3. Heat Pump Sensitivity ........................................................................................... 31
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3.1.
Introduction ................................................................................................... 31
3.2.
Materials and Methods .................................................................................. 32
3.2.1. Heat Pump Technical Data ........................................................................ 32
3.2.2. Heat Pump COP vs Source Temperature .................................................. 33
3.2.3. Overall Sensitivity: Air-to-Air vs Air-to-Water ........................................ 34
3.2.4. Sensitivity per Temperature Range ........................................................... 35
3.2.5. Low Capacity vs High Capacity ................................................................ 35
3.3.
Results ........................................................................................................... 35
3.3.1. Heat Pump COP vs Source Temperature .................................................. 35
3.3.2. Overall Sensitivity: Air-to-Air vs Air-to-Water ........................................ 37
3.3.3. Sensitivity per Temperature Range ........................................................... 38
3.3.4.
3.4.
Low Capacity vs High Capacity ............................................................ 39
Conclusion ..................................................................................................... 39
4. Using Low Exergy Sources with a Heat Pump ..................................................... 41
4.1.
Introduction ................................................................................................... 41
4.2.
Materials and Methods .................................................................................. 41
4.2.1. General Methodology ................................................................................ 41
4.2.2.
Using Indoor Air to Alter Source Temperature ..................................... 45
4.2.3.
Using Indoor Air with Heat Recovery to Alter Source Temperature .... 46
4.2.4.
Using Indoor Air and Waste Heat from Compressor to Alter Source
Temperature .......................................................................................................... 47
4.2.5.
Using Indoor Air with Heat Recovery and Waste Heat from Compressor
to Alter Source Temperature ................................................................................. 48
4.3.
Results ........................................................................................................... 49
4.3.1. Using Indoor Air to Alter Source Temperature ......................................... 49
4.3.2. Using Indoor Air with Heat Recovery to Alter Source Temperature ........ 50
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4.3.3. Using Indoor Air with Waste Heat from Compressor to Alter Source
Temperature .......................................................................................................... 51
4.3.4. Using Indoor Air with Heat Recovery and Waste Heat from Compressor to
Alter Source Temperature ..................................................................................... 52
4.4.
Conclusion ..................................................................................................... 53
5. Conclusion ............................................................................................................. 54
References .................................................................................................................... 56
Appendices ................................................................................................................... 61
Appendix A – Daikin Heat Pump Data .................................................................... 61
Appendix B – Worcester Bosch Heat Pump Data .................................................... 64
Appendix C – Samsung Heat Pump Data ................................................................. 65
Appendix D – Kingspan Heat Pump Data ................................................................ 66
Appendix E – Toshiba Heat Pump Data ................................................................... 67
Appendix F – Extrapolated Heat Pump Data ........................................................... 68
Appendix G – Heat Pump Sensitivity Data .............................................................. 80
Appendix H – Sample Heat Pump COP Calculations .............................................. 82
Using Indoor Air to Alter Source Temperature .................................................... 82
Using Indoor Air with Heat Recovery to Alter Source Temperature ................... 83
Using Indoor Air with Waste Heat from Compressor to Alter Source Temperature
............................................................................................................................... 84
Using Indoor Air with Heat Recovery and Waste Heat from Compressor to Alter
Source Temperature .............................................................................................. 84
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Nomenclature
COP
Coefficient of Performance
CAir
specific heat of air, J/kg°C
EC
Waste energy from the compressor, kW
HREff
heat recovery efficiency
P
pressure
QB
air flow rate of building fan
QE
air flow rate of evaporator fan,
QOutput
heat output from heat pump, kJ/kg
SCOP
Seasonal Coefficient of Performance
SPF
Seasonal Performance Factor
TI
indoor temperature, °C
TO
outdoor temperature, °C
Tsink
temperature of heat sink, K or °C as defined
Tsource
temperature of heat source, K or °C as defined
V
volume
W
work input, kJ/kg
ρAir
density of air, kg/m3
ΔCOP
COP difference
ΔT
temperature difference, K or °C as defined
ΔTs
source temperature difference
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List of Figures
Figure 1. Graphic representation of a heat pump cycle (South West Agricultural
Resource Managment Knowledge Hub, 2013) ............................................................ 18
Figure 2. (a) Schematic diagram showing heat transfer from a cold reservoir to a
warm reservoir with a heat pump, (b) PV diagram for a Carnot cycle (RICE
University, 2016) ......................................................................................................... 19
Figure 3. Exergy flows entering and exiting a Process or Unit Operation (Gunderson,
2011). ........................................................................................................................... 21
Figure 4. Heat pump system using heat recovery from solar generated steam cycle
(Suleman et al., 2014). ................................................................................................. 23
Figure 6. Solar thermal assisted ground source heat pump (Emmi et al., 2015). ........ 24
Figure 5. COP of heat pump compared to temperature difference.(Kuang and Wang,
2003) ............................................................................................................................ 24
Figure 7. COP of water source heat pump and electricity consumption from grid for
the examined FPC areas.(Bellos et al., 2016) .............................................................. 26
Figure 8. COP and storage tank volume for the examined PVT surfaces.(Bellos et al.,
2016) ............................................................................................................................ 26
Figure 9. Summary of observed savings for energy efficiency measures (median)
(Department of Energy & Climate Change, 2012) ...................................................... 29
Figure 10. Air-to-air heat pumps: COP vs source temperature ................................... 36
Figure 11. Air-to-water heat pumps: COP vs source temperature ............................... 36
Figure 12. Overall sensitivity: air-to-air vs air-to-water .............................................. 37
Figure 13. Sensitivity per temperature range ............................................................... 38
Figure 14. Overall heat pump sensitivity per nominal heating capacity...................... 39
Figure 15. Heat pump T2: COP vs Source Temperature line equation ....................... 42
Figure 16. Using indoor air to alter temperature of outdoor air supply ....................... 45
Figure 17. Using indoor air and heat recovery to alter temperature of outdoor air
supply ........................................................................................................................... 46
Figure 18. Using indoor air and waste heat from compressor to alter temperature of
outdoor air supply ........................................................................................................ 47
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Figure 19. Using indoor air with heat recovery and waste heat from compressor to
alter temperature of outdoor air supply ........................................................................ 48
Figure 20. Using indoor air to alter outdoor air temperature: graph ............................ 49
Figure 21. Using indoor air with heat recovery to alter source temperature: graph .... 50
Figure 22. Using indoor air with waste heat from compressor to alter source
temperature: graph ....................................................................................................... 51
Figure 23. Using indoor air with heat recovery and waste heat from compressor to
alter source temperature: results .................................................................................. 52
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List of Tables
Table 1. Anthropogenic low exergy thermal sources in buildings (Carbon Trust, 2016)
...................................................................................................................................... 28
Table 2. Heat pump ID tags and specifications. .......................................................... 33
Table 3. Sample Heating Capacity Table .................................................................... 34
Table 4. Heat pump T2 COP data ................................................................................ 41
Table 5. COP line equation validation ......................................................................... 42
Table 6. Common values for all calculations............................................................... 44
Table 7. Using indoor air to alter source temperature: results ..................................... 49
Table 8. Using indoor air with heat recovery to alter source temperature: results ...... 50
Table 9. Using indoor air with waste heat from compressor to alter source
temperature: results ...................................................................................................... 51
Table 10. Using indoor air with heat recovery and waste heat from compressor to alter
source temperature: results .......................................................................................... 52
Table 11. Daikin heat pump unit specifications (Daikin, 2011) .................................. 61
Table 12. Daikin temperature, heating capacity, power input and COP details (Daikin,
2011) ............................................................................................................................ 61
Table 13. Worcester Bosch heat pump unit specifications (Worcester Bosch Group,
2013) ............................................................................................................................ 64
Table 14. Worcester Bosch Greensource Heating capacities, power inputs and COPs
(Worcester Bosch Group, 2013) .................................................................................. 65
Table 15. Samsung heat pump unit specifications (Samsung, 2015) .......................... 65
Table 16. Samsung heating capacities, power inputs and COPs (Samsung, 2015) ..... 65
Table 17. Kingspan heat pump unit specification (Kingspan, 2011) ........................... 66
Table 18. Kingspan heating capacities, power inputs and COPs (Kingspan, 2011) .... 67
Table 19. Toshiba heat pump unit specifications (Toshiba, 2010b) ............................ 67
Table 20. Toshiba heating capacities, power inputs and COPs (Toshiba, 2010b)....... 67
Table 21. Extrapolated COP figures ............................................................................ 68
Table 22. Overall heat pump sensitivity ...................................................................... 80
Table 23. Heat pump sensitivity per temperature range .............................................. 81
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1. Introduction
1.1. Problem Definition
In response to climate change and a desire to provide energy using renewable sources
driven by fossil fuel depletion, many countries worldwide including those within the
European Union and the United States of America are required to reduce their energy
consumption whilst focusing on improving their use of renewable energy sources
(European Commission, 2014, United States Government, 2013). The majority of
renewable sources are, at present, focused on electricity generation instead of heat
provision. An exception is biomass usage which is capable of being used in combined
heat and power systems (U.S. Energy Information Administration, 2016b, Scottish
Government, 2015). There are studies by authors such as Ghosh (2016) and Weldu and
Assefa (2016) which question the sustainability of large scale biomass usage therefore
it is important to look at other renewable heat sources one of which is heat pumps.
The performance of heat pumps is expressed by the coefficient of performance (COP)
which is analogous to efficiency and is influenced by the difference in temperature
between the heat sink and heat source of the heat pump. Reducing the difference in
temperature between the heat sink and the heat source, by increasing the temperature
of the heat source can lead to an increase in the COP of the heat pump. Increasing the
COP of the heat pump by increasing the source temperature could potentially be
achieved by using low exergy thermal sources from the environment in which it is
installed. Using the surrounding environment together with the heat pump is one of the
ideas promoted by the IEA Heat Pump Centre (2016) which states that heat pumps rely
on the principles of efficient use of renewables and efficient end-use, therefore it is
important to investigate the potential of using low exergy thermal sources in this
manner. The use of low exergy thermal sources and heat recovery from urban facilities
have both been subjects which the European Commission has requested be investigated
(European Commission, 2016b, European Commission, 2016c).
Low exergy thermal sources can be separated into two categories; anthropogenic and
natural. Natural low exergy thermal sources, such as solar energy, have previously been
used in studies by Elliott (2013), Emmi et al. (2015), Suleman et al. (2014) and Kuang
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and Wang (2003) to raise the source temperature of heat pumps and show that this
results in an increased COP. Whilst there are many papers detailing the use of natural
low exergy sources to improve heat pumps, this author found a relative lack in reports
investigating the use of anthropogenic sources in the same manner. Anthropogenic low
exergy thermal sources are readily available within buildings (Carbon Trust, 2016). The
availability of low exergy thermal sources was also stated by Wang and Ma (2015) who
also went on to state that the beneficial use of heat pumps depends on the interaction
between the heat pump and the building. It is therefore deemed of interest to determine
how the interaction between the heat pump and the low exergy thermal sources from
the building could occur and what impact this would have on the coefficient of
performance of the heat pump.
1.2. Aim
The aim of this dissertation is investigate what potential there is for low exergy thermal
sources to be used in order to increase the coefficient of performance of heat pumps,
and how the installation of heat pumps in buildings could include the integration of
existing systems in order to make use of their low exergy thermal outputs.
1.3. Objectives
1. Identify low exergy thermal sources from existing building systems which could
be used to input heat into a variety of heat pumps.
2.
Investigate a variety of heat pumps, comparing how sensitive the coefficient of
performance is to changes in source temperature
3. Using the heat pump determined to be most sensitive, calculate the theoretical
impact on the COP when the source temperature is altered by various
combinations of low exergy thermal sources.
4. Using the results of the calculations, discuss how building systems could be
combined so that they work in harmony and be used to improve the performance
of heat pumps.
1.4. Outline of Methodology
This section outlines the methods which were used throughout the various stages of the
project.
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The first stage was to perform a literature review to ensure that no similar investigations
had previously been performed and also to gain an understanding of the various
elements involved in the project. The project involved using low exergy thermal sources
to improve the coefficient of performance of heat pumps therefore it was necessary to
gain an understanding of the theory of heat pumps, particularly regarding the Carnot
Cycle and how it impacted the coefficient of performance. Given that exergy sources
were also to be identified and used to improve the coefficient of performance of the
heat pump, it was also deemed necessary to gain an understanding of exergy and the
theory behind its ability to improve a heat pump.
Exergy is the ability to provide work to a system. An exergy source can be either
naturally occurring (e.g. solar power, geothermal vents) or anthropogenic (e.g. boiler
flue gases). Anthropogenic low exergy thermal sources were focused on due to an
abundance of existing literature regarding the use of natural exergy sources and a
relative lack of literature on anthropogenic sources. It was identified that most exergy
sources which occur within buildings were anthropogenic in nature, with the majority
of identified systems ejecting heat in the form of waste air. As a result of these findings,
it was decided to focus on air source heat pumps.
Air source heat pumps are manufactured by a number of companies and can be either
air-to-air or air-to-water type heat pumps. Both types of air source heat pumps come in
a variety of specifications primarily identified by their nominal heating capacities and
nominal power inputs. In order to compare air-to air and air-to-water heat pumps,
theoretical sensitivity studies were performed, using Excel, to determine how the COP
of each heat pump reacted as the source temperature was altered. The rate at which the
COP of each heat pump changed per degree of source temperature change was then
calculated in order to define the sensitivity of each heat pump. Firstly, the overall
sensitivity of each heat pump was calculated before the sensitivities within the low,
medium and high source temperature ranges were determined. It was important to
determine if there were any particular ranges in which the heat pumps were most
sensitive as this may have identified which type of climate each heat pump would be
most effective in. After comparing each type of heat pump and determining their
respective sensitivities, a comparison was performed between heat pumps with a low
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nominal heating capacity and those with a high nominal heating capacity to determine
whether the designed nominal heating capacity had an influence on the sensitivity of
the heat pump.
Once the sensitivity analysis was completed, one particular heat pump was selected,
due to its high degree of sensitivity across a number of temperature ranges, for use in
further calculations. The calculations for which the selected heat pump was used were
to define combinations in which the heat pump could be installed to make use of low
exergy sources in the surrounding environment. For each combination of installation, a
schematic was also drawn to give a simplistic visual representation of the installation.
For each combination, the percentage improvement in COP at selected source
temperatures was calculated when the low exergy sources were included, from which
the most effective combination was determined.
After all calculations on heat pump sensitivity and installation effectiveness were
completed, discussions were undertaken to highlight the important results of the
calculations. The future works which could be undertaken to follow on from the results
of this investigation were also discussed.
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2. Literature Review
2.1. Introduction
This literature review covers the main elements of this project such as the theory of heat
pumps, the Carnot Cycle, coefficient of performance, exergy and low exergy thermal
sources. Before delving into these elements of the project, a more complete
understanding of why renewable energy sources and renewable heat sources in
particular are being studied was required.
The most prominent reason for researching renewable technology is climate change.
Climate change is a major global concern, the evidence and effects of which are being
highlighted by organisations such as the United Nations (2013), NASA (2016) and the
European Commission (2016a). The European Commission (2014) passed a directive
in 2010 which stated that by 2020 all new buildings need to be energy efficient to reduce
energy consumption, with the remaining energy demand able to be supplied through
renewable sources, be they on or off-site. This directive came as a result of the
awareness that many of the causes of climate change were anthropogenic in nature,
particularly the use of fossil fuels to provide energy (Cubasch et al., 2013). In an attempt
to reduce their use of fossil fuels, the President of the United States directed The
Department of the Interior to issue permits for 10 gigawatts of renewable energy on
public lands by 2020 which added to the 10 gigawatts they previously permitted in a
similar directive in 2012 (United States Government, 2013).
Increasing the use of renewable energy sources alone will not solve climate change
issues due to the ever increasing usage of energy. According to the U.S. Energy
Information Administration (2016a), the residential sector for European countries in the
Organisation for Economic Co-operation and Development (OECD) region will
experience an energy consumption increase of approximately 0.9% per year between
2012 and 2040, while the commercial sector for the same area experiences an increase
of approximately 1.3% per year between 2012 and 2040. It is also stated that the
growths in OECD Europe is greater than in the United States by 0.7% and 0.6% for the
residential and commercial sectors respectively.
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When considering the United Kingdom as an individual country, it is predicted that
final energy demand will reduce in the forthcoming years until around 2025 before
returning to current levels by 2033 then continuing to increase. The reason for this trend
is that demand in the industrial sector is expected to fall but the domestic sector is
expected to start increasing around 2030 (Department of Energy & Climate Change,
2015). This shows that whilst energy efficiency is a large focus for new buildings, it
will still be competing against an increasing demand which means that it will be
important to continue ensuring that there are enough energy sources to meet this
increased demand.
With the requirement for renewable energy generation continually increasing, it is
important to look at the current breakdown of renewable sources. The majority of
renewable energy generation within the United States of America comes from biomass,
followed by hydro and wind, with only minor generation coming from geothermal and
solar photovoltaic sources, which equates to approximately 13% of electricity
generation for the country (U.S. Energy Information Administration, 2016b). When it
comes to renewable sources in Scotland, generating renewable electricity appears to be
much easier and widespread than generating renewable heat using existing technology.
Statistics from the Scottish Government (2015) state that 44.4% of electricity is
currently supplied by renewable sources however only 3% of heat is supplied by
renewable sources. Based on that information, it can be determined that renewable heat
is the far behind renewable electricity with regards to its level of use. In order to
promote more widespread use, and for the purposes of this report, improving efficiency
in existing technology such as heat pumps must be considered.
2.2. Heat Pumps
2.2.1. Heat Pump Benefits
As mentioned, one of the primary renewable heat technologies available for use in
buildings is that of heat pumps, which come in a variety of types such as air source,
ground source, water source and sewage (waste water) source. Heat pumps are classed
as renewable despite the fact that they require an electrical input to operate, which may
or may not be from a renewable source. It should be noted that some ground source heat
pumps which go to large depths are not strictly renewable as they operate using
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decaying radioactive isotopes in the ground, however given that the decay process is
very long they can be classed amongst renewable heat pumps (Elliott, 2013).
Some benefits of using heat pumps (Energy Saving Trust, 2014):

Lower fuel bills, especially if you are replacing conventional electric heating

Potential income through the UK government’s Renewable Heat Incentive
(RHI)

Lower home carbon emissions, depending on which fuel you are replacing

No fuel deliveries needed

Can heat your home as well as your water

Minimal maintenance required
2.2.2. Heat Pump Operation and the Carnot Cycle
With regards to the operation of a heat pump, it can best be described graphically as
shown in Figure 1 where it can be seen that the heat from the source is used to evaporate
the fluid in the pipe as it passes through the evaporator, before passing through the
compressor. By increasing the pressure of the gas in the pipe the temperature of the gas
increases. The gas is then passed through a condenser which, in the process of
condensing the gas into a fluid, causes the heat to be ejected into the heat sink. The fluid
in the pipe then passes through an expansion valve and back into the evaporator so that
the process can start all over again.
Figure 1. Graphic representation of a heat pump cycle (South West Agricultural Resource Managment
Knowledge Hub, 2013)
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The process which takes place in a heat pump is known as the Carnot Cycle, a diagram
of which is shown below. It is important to be aware of the elements within the Carnot
Cycle as they directly relate to the coefficient of performance of the heat pump.
Figure 2. (a) Schematic diagram showing heat transfer from a cold reservoir to a warm reservoir with
a heat pump, (b) PV diagram for a Carnot cycle (RICE University, 2016)
Part (a) of Figure 2 highlights how the work input to the heat pump is used to transfer
the heat from the cold reservoir (heat source) to the hot reservoir (heat sink). Relating
this back to Figure 1, the work input would be the work performed by the compressor.
Part (b) is a pressure-volume diagram that shows the relationship between pressure,
volume and temperature which was mentioned above when discussing Figure 1.
2.2.3. Coefficient of Performance (COP)
This conversion efficiency of a heat pump is referred to as its Coefficient of
Performance (COP) and is calculated using the formula:
COPheat pump =
Qoutput
Welectrical
(1)
Equation (1) shows that the COP of the heat pump is calculated by dividing the amount
of heat output from the system by the amount of electrical work input into the system.
The greater the amount of heat output from the system naturally increases the COP of
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the system if the electrical input stays constant. The test procedure for calculating the
COP of heat pumps is dictated by EN 14511 which defines the boundary conditions
which must be adhered to (Klein, 2012). It is important that all manufacturers are
required to test under the same conditions as it means that all figures used in data sheets
can be compared in the knowledge that any differences are down to the specifications
of the heat pumps and not the conditions they were tested under.
Some manufacturers state on their website that heat pumps are around 300% efficient
(Daikin, 2016a), whilst Elliott (2013) states that this is only a theoretical potential and
that adverse weather conditions could mean that the heat pump does not generate three
times the energy value of electricity input to make it operate. Whilst many heat pumps
routinely achieve this level of efficiency, the key point to remember is that adverse
conditions could reduce efficiency. It should also be noted that the efficiency discussed
is the conversion efficiency of the heat pump, not the thermal efficiency.
The thermal efficiency of a heat pump is known as the Carnot COP of the heat pump
which is used to determine the maximum theoretical COP possible. The Carnot COP
can be calculated using the following equation, ensuring that all temperature values are
in Kelvin (K):
𝐶𝑂𝑃ℎ𝑒𝑎𝑡 𝑝𝑢𝑚𝑝,𝐶𝑎𝑟𝑛𝑜𝑡 =
𝑇𝑠𝑖𝑛𝑘
𝑇𝑠𝑖𝑛𝑘 − 𝑇𝑠𝑜𝑢𝑟𝑐𝑒
(2)
It can be seen from Equation (2) that in order to maximise the COP of the heat pump,
the temperature difference between the heat sink and the heat source must be
minimised. The avenue explored in this project is to use an external thermal source to
raise the source temperature so that it is closer to the temperature of the sink.
Whilst the coefficient of performance indicates the efficiency of a heat pump at a given
temperature, a more accurate representation of the heat pump efficiency is known as
the seasonal coefficient of performance (SCOP) or seasonal performance factor (SPF)
(Heat Pump Association, 2014). The SCOP is a representation of the COP of the heat
pump taking into account the variations in efficiency over a period of time caused by
fluctuations in temperature (Daikin, 2016b). The SCOP of a heat pump is calculated
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according to the European Standard, EN 14825, with a requirement to calculated the
SCOP for the average climate of Strasbourg whilst it is voluntary to calculate the SCOP
for the warmer and colder climates of Athens and Helsinki respectively (Rasmussen,
2011).
2.3. Exergy
Exergy is the ability of a system to produce work as it moves into thermodynamic
equilibrium with its surroundings (Gundersen, 2011). During the operation of a system,
the exergy, unlike energy, can be destroyed thus the exergy leaving is diminished
compared to that entering the system as shown in Figure 3, below:
Figure 3. Exergy flows entering and exiting a Process or Unit Operation (Gunderson, 2011).
It is important to note that Dinçer and Rosen (2012) have stated that exergy can be input
into a system thereby increasing the exergy of that system. If the exergy leaving a
system is in the form of heat, it could be theorised that by inputting this into another
thermodynamic process such as a heat pump, it could improve the exergy of that system.
Regarding the form of exergy sources, it was found that they could come from many
places such as external exergy resources (natural resources, e.g. solar energy) or waste
exergy emissions from anthropogenic processes (Dinçer and Rosen, 2012).
2.4. Using Natural Exergy Thermal Sources with Heat Pump Systems
It has been found that natural exergy sources are the most commonly used alongside
heat pumps, namely solar and geothermal resources. Typically, these sources are
considered to have a finite thermal capacity due to the fact that boreholes degrade over
a number of years and there is lack of solar energy during the night.
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As mentioned earlier, it is possible to use exergy sources to assist the operation of heat
pump systems, however investigation into this has so far been limited to using natural
exergy sources to compliment heat pumps as shown by Scarpa and Tagliafico (2016),
instead of using them to improve the COP of the heat pump. These authors investigated
how direct-expansion solar assisted heat pumps could be improved by utilising
condensation which occurs on the solar collector if it is kept under the dew point
temperature. It was found that the temperature of the solar collector had to be optimised
to balance the energy generated through the condensation process against the COP of
the heat pump because the COP would be negatively affected as the temperature of the
solar collector was decreased.
Likewise Cho (2015) utilised solar energy as a low exergy thermal source by attaching
a solar collector to a heat pump system. In this instance, when conditions were
appropriate, the system used direct solar heat without requiring to use the heat pump.
In essence, the heat pump was a back-up system in the arrangement, so the natural
exergy source could not be considered to have an effect on the COP of the heat pump.
An integrated solar heat pump system, as shown in Figure 4, was studied by Suleman
et al. (2014) which incorporated both a solar collector and a heat pump in two systems,
linked through a heat recovery unit, which fed into the heat pump. Initially the solar
generated heat was used for various processes, with the heat degrading each time,
however at the last process the waste heat was recovered and increased by the heat
pump in order to be fed back into this last process.
The system was in essence utilising a low exergy thermal source to increase the
temperature of the air feeding into the heat pump. When considering the COP of the
heat pump, variations were made to the ambient air temperature and the temperature at
the condenser, however no studies looked at how the COP of the heat pump could be
affected by a change in the temperature generated by the solar collector, especially over
a sustained period of time.
Page | 22
Figure 4. Heat pump system using heat recovery from solar generated steam cycle (Suleman et al., 2014).
One study which was found to analyse how solar heat could be used to raise the
temperature of water being used as the source for a water source heat pump was
undertaken by Kuang and Wang (2003). The experimentation period for the heat pump
occurred under the worst seasonal conditions for that area, so they were able to
determine whether the heat pump would work when it was most required. Through their
experiments, they concluded that under their specific conditions an auxiliary energy
source was required to aid the solar collector as the solar heat was not sufficient to keep
the water in the storage tank within the required temperature range. Unfortunately,
when measuring the effect on the COP, the experiment relied on the condensing
temperature changing due to the auxiliary heat source keeping the evaporating
temperature relatively stable. This meant that whilst it was shown in Figure 6 that the
COP of the heat pump improved as the temperature difference reduced, the actual effect
of the solar heat could not be properly assessed.
Page | 23
Figure 6. COP of heat pump compared to temperature difference.(Kuang and Wang, 2003)
Solar assisted ground source heat pumps were studied by Emmi et al. (2015) in order
to determine whether the efficiency of ground source heat pumps could be improved by
pumping excess solar thermal energy into boreholes. They used TRNSYS in order to
use computer simulations to investigate how the heat pump would operate in cold
climates, taking into account the building requirements throughout. The simulation
involved an identical building being investigated in six different climates. Certain other
elements of the model were constant throughout the six scenarios such as the size of the
water storage tank and solar collectors whilst variable elements included the type of
heat pump used and total length of the boreholes.
Figure 5. Solar thermal assisted ground source heat pump (Emmi et al., 2015).
As shown in Figure 5, the system was set up so the solar heat could raise the temperature
of the water within the storage tank which was coupled with the heat exchangers in the
ground source heat pump. If there was insufficient solar heat, the ground source heat
pump could operate on its own to provide heating. Likewise, if heating was not required
within the building, the loop could be closed so that the solar thermal heat could be
Page | 24
pumped down into the borehole. The system also had a free-heating control within it so
that if the required temperatures were reached, the heat pump could be bypassed. The
reason for these controls was to minimise the exergy usage within the system as a
whole, therefore increasing its efficiency.
The system can only be considered to improve the COP of the heat pump however if
the solar thermal source is being used to raise the temperature in the water tank before
it is passed through the heat pump. The result most relevant to this project coming from
the TRNSYS simulation was the direct comparison between a regular ground source
heat pump and the solar assisted ground source heat pump. The results showed that at
the tenth year of the simulation, the COP of the solar assisted ground source heat pump
was between 7% and 27% higher across the different climates when compared to the
normal ground source heat pump. This indicates that supplying exergy in the form of
thermal heat does have a positive effect on the COP of the heat pump.
A study by Bellos et al. (2016) involved using TRNSYS to review the effect on both
air source and water source heat pumps if solar energy was used to assist the system.
With regards to the air source heat pump, the solar energy is solely used to power the
heat pump, minimising the amount of energy required from the grid, however with the
water source heat pump, heat is generated at the solar collector and supplied to a water
storage tank which in turn feeds the water source heat pump. For the water source heat
pump, two types of system are tested, the first featuring flat plate collectors and the
second using photovoltaic panels.
Page | 25
Figure 7. COP of water source heat pump and electricity consumption from grid for the examined FPC
areas.(Bellos et al., 2016)
Figure 8. COP and storage tank volume for the examined PVT surfaces.(Bellos et al., 2016)
It was shown in the study that for both the simulation involving the flat plate collectors
and that involving the photovoltaic panels, the COP of the water source heat pump
increased as the collecting areas were increased, due to higher temperatures being
involved, however it can be seen in Figure 7 and Figure 8 that in order to achieve the
required temperatures within the building, around 20m2 of collectors/panels were
required.
2.5. Using Anthropogenic Exergy Thermal Sources with Heat Pump Systems
There is a lot of potential for using anthropogenic exergy sources, such as waste heat
from industrial processes (European Heat Pump Association, 2015) or from fossil fuel
driven systems within existing buildings, to improve the COP of heat pumps however
there has not been a lot of study into this topic. These anthropogenic exergy sources,
unlike natural exergy sources, could be considered to have an infinite thermal reservoir
Page | 26
if they were run 100% of the time, however in real conditions these would most likely
also be finite as the machinery would only run intermittently.
The method of using heat pumps to recover low grade waste heat and upgrade it to
process heat in the industrial sector was considered by van der Bor et al. (2015) who
analysed whether this was a better option than converting waste heat to electricity using
a heat engine. It was determined that at waste inlet temperatures of 60°C or lower, heat
pumps were 2.5-11 times more economically viable, but that heat engines become more
viable at temperatures of 100°C or greater. While the study concludes that vapour
compression heat pumps show a limited capability to upgrade waste heat streams, it
does confirm that the COP decreases as the temperature difference between the waste
outlets increases.
A study was carried out by Kim et al. (2013) who compared the performance of hybrid
heat pumps to raise the temperature of waste heat compared to conventional boilers. It
found that heat pumps provided much higher energy savings than boilers, however heat
pumps were not able to reach the same temperature ranges as conventional boilers.
Some work has been done to study the effects of using waste heat to power absorption
heat pumps (Wu et al., 2014) which is not directly relevant to this topic, however it does
provide further evidence that low exergy sources of heat could be beneficial to the
operation of heat pump systems. In the cases studied in the article, the use of waste heat
in absorption heat pumps was particularly ideal in rural areas with little access to
electricity.
Ommen et al. (2014) investigated the effect on the COP of a heat pump when integrated
into a district heating scheme in a variety of different configurations. Within the study
it discussed that by decentralising heat pumps within a larger district heating network,
the pumps could utilise sources such as waste heat which has higher than ambient
temperatures. Whilst not all configurations are relevant, two in which the heat pump
utilises the return line from the district heating system as its source, are. When the
results were analysed, the two aforementioned configurations had the highest COPs,
with the highest overall COP being reached by the configuration which raised the return
Page | 27
temperature for input into the CHP system as opposed to the configuration which raised
the return temperature and supplied it to the output of the CHP system.
2.6. Identifying Low Exergy Thermal Sources in Buildings
It was defined earlier that an exergy source is one which can provide work to another
system thereby improving the performance of that system. With that in mind, a low
exergy source is one which is only capable of providing a low level of work to another
system. Given that the work provided by an exergy source can be in the form of heat, a
low exergy thermal source must therefore be a source which supplies a low level of heat
to a system to improve its performance.
As there has been an abundance of investigations involving the use of natural low
exergy thermal sources to improve the coefficient of performance of heat pumps, it was
decided to focus on anthropogenic sources for further investigation. The anthropogenic
low exergy thermal sources needed to improve the coefficient of performance of heat
pumps must be available from the environment in which the heat pump is installed if
any benefit is to be achieved with relative ease. Given that heat pumps are installed in
building environments, the low exergy thermal sources must come from the
anthropogenic systems at work within the building. There are many anthropogenic low
exergy thermal sources within buildings, a list of which is contained on a Carbon Trust
(2016) website discussing heat recovery from buildings. This list forms the first column
in Table 1, below. Rather than being a complete list of all the individual variations
which could occur, the list details the basic systems which could give off the waste heat.
Table 1. Anthropogenic low exergy thermal sources in buildings (Carbon Trust, 2016)
Source
Transience
Medium
Air compressors
Daily
Air
Boiler blowdown
Daily
Air
Boiler flue gases
High temperature exhaust gas streams
from furnaces, kilns, ovens and dryers
Daily
Air
Daily
Air
Hot liquid effluents
Daily
Water
Power generation plant
Ad Hoc
Air
Process plant cooling systems.
Daily
Air/Water
Refrigeration plant
Constant
Air
Ventilation system extracts
Daily/Constant
Air
Page | 28
It can be seen from Table 1 that most of the anthropogenic low exergy sources available
within a building take the form of exhaust air from existing systems within the building.
This prevalence of heated air sources indicates that the most likely heat pumps to
investigate are air source heat pumps, however it should be noted that water source heat
pumps could also be used if the hot air was used to heat water in a storage tank.
2.7. Energy Savings from Building Upgrades
It has been stated that improving the COP of heat pumps is improving their efficiency,
therefore it must be the case that there are energy savings involved when improving the
COP. In order to accurately assess the potential of heat pumps with regards to energy
savings, a comparison must be made against other energy saving measures such as
building upgrades.
Figure 9. Summary of observed savings for energy efficiency measures (median) (Department of
Energy & Climate Change, 2012)
It can be seen from Figure 9 that condensing boilers led to the highest energy savings,
approximately 12% in 2005 through to 2007, however was no longer recorder
thereafter. Cavity wall insulation led to the next highest savings, routinely achieving
around 9% energy savings between 2005 and 2009. The measure which achieved the
lowest percentage energy saving, approximately 2%, was loft insulation.
Page | 29
2.8. Conclusions
Based on the literature reviewed, it can be seen that there has been limited investigation
into ways in which low exergy thermal sources could be utilised to increase the COP
of a heat pump, however they have been focused on using natural exergy sources such
as solar to improve water and geothermal source heat pumps. These studies highlighted
that there is definite potential for low exergy sources to increase the COP of heat pumps,
however they have not investigated in detail how effective anthropogenic exergy
sources could be.
When identifying anthropogenic low exergy thermal sources, it was determined that
most of these take the form of heated waste air, which lead to the conclusion that air
source heat pumps should be concentrated on for future investigations within this
report.
Page | 30
3. Heat Pump Sensitivity
3.1. Introduction
The strong dependency of COP to ΔT is widely advertised in scientific journals (Bellos
et al., 2016, Cho, 2015) as well as on the websites of heat pump manufacturers and
sellers (Kensa Heat Pumps, 2016, Industrial Heat Pumps, 2016). Also, based on Carnot
theorem, it is accepted that the COP values of heat pumps are sensitive to temperature
changes, be they source or sink temperature changes as earlier stated in Equation (2).
However, through reviewing various makes and models of heat pumps it was noted that
sensitivity to temperature difference can vary greatly, especially within particular
temperature ranges.
When calculating the COP of a heat pump, manufacturers must conform to EN14511
standards to ensure that boundary conditions for testing are consistent across products,
with these boundary conditions primarily relating to temperatures for different sinks
and sources such as brine, water or air. In his article for REHVA, Klein (2012) stated
that there are other factors which could affect the COP of a heat pump such as the
occasional requirement to defrost the evaporator in colder conditions or the power
consumption of any pumps and fans within the system. It is reasonable to assume that
the heat pumps available on the market have different makes of pumps and fans,
operating with different efficiencies and power requirements which may explain why
heat pumps from different manufacturers have different trends when displayed
graphically.
The aim of this section was to perform a comparison of multiple heat pumps and to
analyse how they react to changes in source temperature. It was shown in Table 1 of
this report that most low exergy thermal sources available from buildings take the form
of waste air and as such it was decided to focus on air-to-air and air-to-water heat
pumps. It could be argued that water source heat pumps could also be included in the
comparison as there are many benefits to using them, such as sustaining an increased
COP through storing waste heat in a storage tank. Whilst they could lead to prolonged
increased COP compared to air source heat pumps being fed from the same low exergy
thermal source, studies such as Kuang and Wang (2003) and Bellos et al. (2016) have
Page | 31
already sufficiently discussed the sensitivity of water source heat pumps to temperature
changes.
3.2. Materials and Methods
3.2.1. Heat Pump Technical Data
In Table 2, below, the heat pumps being used for the comparison are listed, detailing
the manufacturer, series, model combination, nominal heating capacities and nominal
power inputs. It should be noted that these particular models were chosen because an
appropriate amount of technical data was available for each, including heating capacity
information with at least four different temperature data points. Additional information
for each heat pump, including the number of data points and the specific sink and source
temperatures used, is included in Appendix A – Daikin Heat Pump Data through to
Appendix E – Toshiba Heat Pump Data.
The majority of selected heat pumps were air-to-air heat pumps however air-to-water
heat pumps were also selected in order to observe whether they reacted differently to
air-to-air heat pumps. Additionally, heat pumps of varying heating capacities and power
inputs were selected to determine if the size of the unit had any effect on its sensitivity
to changes in source temperature.
Page | 32
Table 2. Heat pump ID tags and specifications.
Nominal
Power Input Heating (kW)
16
4
(Daikin, 2011)
25
5.56
(Daikin, 2011)
31.5
7.7
(Daikin, 2011)
37.5
9.44
(Daikin, 2011)
45
11.3
(Daikin, 2011)
50
12.9
(Daikin, 2011)
56.5
15.3
(Daikin, 2011)
ID tag
Manufacturer
D1
Daikin
VRV III
D2
Daikin
VRV III
D3
Daikin
VRV III
D4
Daikin
VRV III
D5
Daikin
VRV III
D6
Daikin
VRV III
D7
Daikin
VRV III
Model Combination
RXYQ5P9W1B +
RXYQ-5P9
RXYQ5P9W1B +
RXYQ-8P9
RXYQ5P9W1B +
RXYQ-10P9
RXYQ5P9W1B +
RXYQ-12P9
RXYQ5P9W1B +
RXYQ-14P9
RXYQ5P9W1B +
RXYQ-16P9
RXYQ5P9W1B +
RXYQ-18P9
K1
Kingspan
Aeromax Plus
4kW
4.1
1.01
(Kingspan, 2011)
K2
Kingspan
Aeromax Plus
6kW
5.8
1.37
(Kingspan, 2011)
K3
Kingspan
Aeromax Plus
8kW
7.2
1.82
(Kingspan, 2011)
K4
Kingspan
Aeromax Plus
12kW
11.9
3.01
(Kingspan, 2011)
K5
Kingspan
3.57
(Kingspan, 2011)
Samsung
4.6
1.3
(Samsung, 2015)
S2
Samsung
4.75
1.39
(Samsung, 2015)
S3
Samsung
4.6
1.4
(Samsung, 2015)
S4
Samsung
5
1.4
(Samsung, 2015)
S5
Samsung
7.5
2.4
(Samsung, 2015)
S6
Samsung
9
3.6
(Samsung, 2015)
S7
Samsung
10
3.8
(Samsung, 2015)
T1
Toshiba
Estia
8
1.82
(Toshiba, 2010b)
T2
Toshiba
Estia
11.2
2.35
(Toshiba, 2010b)
T3
Toshiba
Worcester
Bosch
Estia
15kW
AC026FCADEH/EU +
AC026FB1DEH/EU
AC035FCADEH/EU +
AC035FB1DEH/EU
AC026FCADEH/EU +
AC026FBNDEH/EU
AC035FCADEH/EU +
AC035FBNDEH/EU
AC052FCADEH/EU +
AC052FBNDEH/EU
AC060FCADEH/EU +
AC060FBNDEH/EU
AC071FCADEH/EU +
AC071FBNDEH/EU
HWS-803H-E + HWS803XWH**-E
HWS-1103H-E +
HWS-1403XWH**-E
HWS-1403H-E +
HWS-1403XWH**-E
14.5
S1
Aeromax Plus
Slim 1 Way
Cassette
Slim 1 Way
Cassette
Mini 4 Way
Cassette
Mini 4 Way
Cassette
Mini 4 Way
Cassette
Mini 4 Way
Cassette
Mini 4 Way
Cassette
14
3.11
Greensource
7-716-150-179
4
1.3
(Toshiba, 2010b)
(Worcester Bosch
Group, 2013)
WB1
Series
Nominal
Heating
Capacity
(kW)
Source
3.2.2. Heat Pump COP vs Source Temperature
In order to properly compare the sensitivity of heat pumps, samples of air source heat
pumps were selected from a number of brands and figures were taken from heating
Page | 33
capacity tables within their respective data sheets. An example of one of these tables is
shown below in Table 3.
Table 3. Sample Heating Capacity Table
ID
Tag
Sink
Temperature
(°C)
Source
Temperature
(°C)
Heating
Capacity
(kW)
Power
Input
(kW)
S1
20
-15
2.31
1.10
S1
20
-10
2.72
1.07
S1
20
7
3.30
0.91
S1
20
24
3.52
0.96
The source temperature values shown in the sample table shown above, and the
respective tables for the other heat pumps, were outdoor air temperature values. For
each source temperature, the heating capacity and power input values were used with
Equation (1) in order to calculate COP values which could be used to create COP vs
Source Temperature profiles. The full tables containing the technical data and
calculated COP values for each heat pump are included in the appendices Appendix A
– Daikin Heat Pump Data through to Appendix E – Toshiba Heat Pump Data.
Due to the different amount of source temperature data points across the manufacturers,
the initial graphical comparison of the COP vs Source Temperature profiles consisted
of discontinuous plots which made it difficult to perform an accurate comparison. To
rectify this, each manufacturer’s data was extrapolated to ensure the profiles passed
through all temperature data points between their first and last points, thus resulting in
unbroken graphical profiles. The tables containing the extrapolated data are included in
Appendix F – Extrapolated Heat Pump Data.
3.2.3. Overall Sensitivity: Air-to-Air vs Air-to-Water
The variable nature of the COP vs Source Temperature profile, particularly the
instances where the COP decreased instead of increasing, meant that the results required
further analysis. The rate of change of the COP (ΔCOP) per the change in source
temperature (ΔTs), ΔCOP/ΔTs provided a clear way of analysing the sensitivity of the
heat pump, therefore it was used to determine the overall sensitivity of each of the heat
pumps.
Page | 34
3.2.4. Sensitivity per Temperature Range
It was clear that the overall sensitivity analysis of the heat pumps was not sufficiently
in-depth therefore further analyses were performed using the same method, but
grouping the source temperatures as either low, medium or high temperature ranges.
By looking at each range distinctly the rate of COP increase for each heat pump could
be determined and could be used to determine if there were any particular temperature
ranges in which the heat pumps were more sensitive. At this stage each heat pump
was compared directly, with no distinction made between air-to-air and air-to-water
heat pumps.
3.2.5. Low Capacity vs High Capacity
After comparing sensitivity of the heat pumps across various temperature ranges and
heat pump types, it was decided to determine whether the sensitivity of the heat
pumps was determined by the nominal heating capacity of the heat pumps. To do this,
the nominal heating capacities were divided into two ranges; “low” encompassing
nominal heating capacities up to 10kW and “high” encompassing nominal heating
capacities from 11kW upwards.
3.3. Results
3.3.1. Heat Pump COP vs Source Temperature
In the two graphs below, Figure 10 and Figure 11 the lines represent the COP of each
heat pump as the source temperature increases. It should be noted that Figure 10
pertains to air-to-air source heat pumps, designated D, S and WB, with sink temperature
of 20°C whilst Figure 11 pertains to air-to-water source heat pumps designated K and
T with sink temperature of 35°C.
Page | 35
Figure 10. Air-to-air heat pumps: COP vs
Figure 11. Air-to-water heat pumps: COP vs
source temperature
source temperature
It can be seen from Figure 10 that there was a lot of variation between the heat pumps,
which whilst indicating that overall all COPs increase as the source temperature is
increased, also shows that even amongst manufacturers there is no uniformity. There
are also instances on the graph above which show the COP decreasing as the source
temperature is increasing which seems to be in direct contradiction to Carnot Theorem.
It should be noted that for heat pumps designated certain heat pumps, the COP reduction
between 20°C and 24°C was due to the source temperature exceeding the sink
temperature therefore this was not considered to be a potential issue.
Contrary to Figure 10, the heat pumps included in Figure 11 followed similar trends to
one another albeit with minor differences in magnitude. The major difference between
the heat pumps was the range of source temperature across which COP data was
available, with some heat pumps covering a much smaller range than the rest. It was
determined that heat pump T2 had the most obvious variation to the other heat pumps
in the source temperature range between 5°C and 15°C.
Page | 36
As the y-axis of the two graphs were the same, it could be seen that the air-to-water
heat pumps had a steeper profile than those of the air-to-air heat pumps which indicated
that overall they appear to have a greater sensitivity to source temperature change.
3.3.2. Overall Sensitivity: Air-to-Air vs Air-to-Water
Figure 12. Overall sensitivity: air-to-air vs air-to-water
It can be seen in Figure 12 that there is a vast difference in sensitivity between the airto-air and air-to-water heat pumps, which confirms that which had been previously
indicated in Figure 10 and Figure 11. The air-to-water source heat pumps were seen to
be approximately twice as sensitive as the selected air-to-air heat pumps.
Overall the heat pump with the highest sensitivity was K2 of which the COP increased
by 0.13 every degree whilst the heat pump with the lowest sensitivity was D7 which
only increased by 0.02 every degree indicating that K2 is 6.5 times more sensitive than
D7.
Page | 37
3.3.3. Sensitivity per Temperature Range
Figure 13. Sensitivity per temperature range
When split into temperature ranges, it can be seen that the sensitivity of heat pumps is
more complex than when viewed overall. In the low temperature range, which
encompasses temperatures from -20°C to -5°C, heat pumps D4 and D7 both decrease
by -0.01 per degree. The other heat pumps designated D had a lower COP increase rate
in the low temperature range compared to the medium temperature range where they
approximately doubled. The rate dropped again in the high temperature range where
heat pumps S2 and S4 became negative. Conversely it can be seen that the rate at which
the COP of heat pumps S1 to S7 increased was greater in the low temperature range
than it was in the medium temperature range. The COP increase rates were even lower
when those heat pumps moved into the high temperature range.
The heat pumps designated T followed a similar path to heat pumps designated S.
Within the medium temperature range, heat pump T2 reached the greatest sensitivity
with the COP increasing by 0.18 for every degree of increase in source temperature.
The K type heat pumps were limited to the medium temperature range therefore no
comparison with the low and high ranges could be performed. The biggest difference
between the temperature ranges was that of the WB type heat pump whose sensitivity
tripled in the medium range compared to the low temperature range.
Page | 38
3.3.4. Low Capacity vs High Capacity
It can clearly be seen from Figure 14 that the sensitivity of the heat pumps was not
directly related to the nominal heating capacity range to which they were designed. It
can be seen that many of the least sensitive heat pumps are within the high nominal
heating capacity range whilst the most sensitive heat pumps are contained both within
the low and high nominal heating capacity ranges.
Figure 14. Overall heat pump sensitivity per nominal heating capacity
3.4. Conclusion
Within this section of the report it was intended to investigate the sensitivity of heat
pumps by evaluating the rate at which the COP of the heat pumps altered as the source
temperature was increased. It was discovered, from the sources available, that air-towater heat pumps tend to be more sensitive than air-to-air heat pumps, being almost
twice as sensitive in most circumstances. It was also determined that the nominal
heating capacity, which the heat pump was designed to meet, has no direct effect on the
sensitivity of the heat pump to source temperature change.
One of the most prominent discoveries of the analysis was that there were instances
where the COP of a heat pump would decrease as the source temperature was increased,
typically occurring at very low source temperatures. Further investigation should be
undertaken in future to determine the root cause of this decrease in COP, whether it be
that the efficiencies of individual parts within the heat pump system drive down the
COP or whether it be dependent on the type of refrigerant fluid used within the system.
Page | 39
Based on the analysis performed above it was determined that overall the heat pump
with the highest sensitivity was K2, however this particular heat pump only had data
over a small range of source temperatures, as did the other heat pumps designated K
which achieved high sensitivity. Looking at the highest sensitivity out of the other heat
pumps, it was determined that T2 had a sufficiently high sensitivity over a large range
of source temperatures. When reviewing the temperature ranges, it was discovered that
T2 reached the highest overall sensitivity of all the heat pumps when in the medium
temperature range, maintaining a high sensitivity in the high temperature range,
however in the low temperature range the sensitivity of the heat pump is only around a
quarter of that experienced in the medium temperature range.
Page | 40
4. Using Low Exergy Sources with a Heat Pump
4.1. Introduction
There are many ways in which low exergy sources could be incorporated into a heat
pump system, therefore it is important to gain an understanding of the potential impacts
these different schemes could lead to. In order to gain an understanding of many of
these potential effects, four schemes were selected and are individually detailed below.
From the analysis of the schemes, it was hoped to determine whether there were
improvements to the COP of the heat pump through incorporating the low exergy
sources, and also to determine whether one particular scheme stood out as being the
most advantageous.
4.2. Materials and Methods
4.2.1. General Methodology
In the previous section heat pump T2 was determined to be the most sensitive of the
heat pumps which covered a large range of source temperatures, therefore it was
selected as the heat pump for use within this section of the report. Based on the COP
data from its technical data sheet, shown below in Table 4, a graph, Figure 15, was
created indicating the equation of the line for COP vs Source Temperature which could
be used in future calculations.
Table 4. Heat pump T2 COP data
Sink
Temperature
(°C)
Source
Temperature
(°C)
Temperature
Difference
(ΔT) (°C)
Heating
Capacity
(kW)
Power
Input
(kW)
COP
Carnot
COP
T2
35
-20
55
5.48
2.97
1.85
5.60
T2
35
-15
50
6.86
3.09
2.22
6.16
T2
35
-7
42
8
3.4
2.35
7.33
T2
35
-2
37
9.9
3.35
2.96
8.32
T2
35
2
33
10.55
3.3
3.20
9.33
T2
35
7
28
14.97
3.23
4.63
11.00
T2
35
10
25
15.87
3.21
4.94
12.32
T2
35
12
23
16.62
3
5.54
13.39
T2
35
15
20
17.7
3.19
5.55
15.40
T2
35
20
15
20.01
3.17
6.31
20.53
ID
Tag
Page | 41
7.00
y = 0.0022x2 + 0.1201x + 3.3424
R² = 0.9692
6.00
5.00
COP
4.00
3.00
2.00
1.00
0.00
-25
-20
-15
-10
-5
0
5
10
15
20
25
Source Temperature (°C)
Figure 15. Heat pump T2: COP vs Source Temperature line equation
The equation for the relationship between COP and source temperature (°C) is shown
below in Equation (3), which according to the R2 number of 0.9692 is approximately
97% accurate based on the source data.
𝐶𝑂𝑃 = 0.0022𝑇𝑠𝑜𝑢𝑟𝑐𝑒 2 + 0.1201𝑇𝑠𝑜𝑢𝑟𝑐𝑒 + 3.3424
(3)
To prove the accuracy of the line equation given, it was used to determine the
percentage difference between the actual COP and the calculated COP when using the
known source temperature figures.
Table 5. COP line equation validation
Source Temperature (°C)
COP
Calculated COP
Difference
% Difference
-20
1.85
1.82
0.02
1.34%
-15
2.22
2.04
0.18
8.30%
-7
2.35
2.61
-0.26
-10.90%
-2
2.96
3.11
-0.16
-5.27%
2
3.20
3.59
-0.39
-12.34%
7
4.63
4.29
0.34
7.42%
10
4.94
4.76
0.18
3.65%
12
5.54
5.10
0.44
7.94%
15
5.55
5.64
-0.09
-1.63%
20
6.31
6.62
-0.31
-4.94%
Page | 42
It can be seen from table that the largest percentage difference between the actual COP
and calculated COP was 12.34% occurring when the source temperature was 2°C. The
percentage differences vary due to the fact that a second order polynomial equation was
used which is more linear than the actual trend of the COP to Source Temperature line,
which was also the reason that some differences were positive whilst others were
negative. To reduce the percentage difference between the COP values, a higher order
polynomial equation could have been used, however it was decided that for the purposes
of this report, the percentage difference values were acceptable.
Given that it was an air to water heat pump which was selected, it was convenient to
consider the system to be supplying an underfloor heating network, which CIBSE
(2010) indicated should operate with a low temperature range, between 35°C and 40°C.
As the technical data for the chosen heat pump referenced a water outlet temperature of
35°C, it was decided to use this value in future calculations. It was also assumed that
the heat pump was maintaining an indoor air temperature, TI, of 20°C. The source
temperature described in the technical data sheet was renamed as the outdoor
temperature, TO, to avoid confusion because the calculations described from here
onwards calculate new source temperatures. The schematics shown in the sub-sections
below are simplistic theoretical representations of the heat pump system and therefore
do not show the condenser submerged in a water tank feeding the pipe network
attributed to an underfloor heating network.
The building air flow rate used for the calculations was 8 litres per second per person
(Clark, 2013). For use in the calculation the litres per second figures was converted to
cubic metres per second, with an assumption made that the room contained twenty
people. The flow rate of the fan in the evaporator unit was stated as 101m3/h which
converted to 1.68m3/s (Toshiba, 2010b). It should be noted that Equations (5),(6),(7)
and (8) are only accurate if the air flow rate from the building is lower than the air
flow rate of the fan within the evaporator.
The compressor used within the selected heat pump is the Toshiba DA422A3F-25M
which is a twin rotary type with DC-inverter variable speed control (Toshiba, 2010a).
An accurate efficiency was unable to be attained from any technical data sheet,
Page | 43
therefore an estimated efficiency of 75% was used, based on information gained in an
online article (Campbell, 2011). The heat recovery unit used for the calculations was
the Toshiba VN-M350HE which was up to 83% efficient according to its technical data
sheet (Toshiba, 2013). The above-mentioned figures are all shown in Table 6, below.
Table 6. Common values for all calculations.
Category
Air Density
Value
1.2
Unit
Symbol
kg/m3
ρAir
CAir
Air Specific Heat
1000
J/kg°C
Heat Pump Nominal Power
2350
W
Indoor Temperature
20
°C
Water Outlet Temperature
35
°C
Heat Recovery Efficiency
0.83
Air Flow Rate – Evaporator Fan
1.68
m3/s
QE
Air Flow Rate - Building
0.16
m3/s
QB
Waste Energy - Compressor
590
W
EC
TI
HREff
Once the new source temperatures were calculated using Equations (5), (6), (7) and (8),
the new COP figures were calculated using Equation (3).
In order to equate a COP increase to an energy saving, it had to be understood that the
heat output, QOutput, of the heat pump would remain the same when the COP
increased, meaning that the work input, W would be reduced. Given that Q is
constant, Equation (1) could be altered as follows:
𝐶𝑂𝑃1 × 𝑊1 = 𝐶𝑂𝑃2 × 𝑊2
(4)
Once the new coefficient of performance, COP2, is calculated, both W1 and W2 can
could be calculated, enabling the percentage difference between the work input values
to be calculated. This difference in work input values equates to the energy saving
resulting from the increase in COP.
Page | 44
4.2.2. Using Indoor Air to Alter Source Temperature
Outdoor
Air
Expansion Valve
Indoor Air
Air Mixer
Evaporator
Compressor
Condenser
Figure 16. Using indoor air to alter temperature of outdoor air supply
The schematic shown in Figure 16 is a theoretical configuration which indicates that
the air source heat pump was fed by a mixture of outdoor air and indoor air directly
vented into the air mixer. The indoor air should cause the temperature of the outdoor
air within the air mixer to increase before being supplied to the evaporator unit.
Theoretically, upon start-up of the heat pump, the indoor temperature would be low and
increase as the heating system stabilises the temperature within the room. For the
purposes of these calculations it was assumed that the room had already reached
temperature. These assumptions isolated the effect which the outdoor temperature has
on the COP.
The impact of the indoor air on the outdoor air supply had to be taken into account,
which resulted in Equation (5), shown below:
𝑇𝑠𝑜𝑢𝑟𝑐𝑒 =
(𝑇𝑂 × (𝑄𝐸 − 𝑄𝐵 ) + 𝑇𝐼 × 𝑄𝐵 )
𝑄𝐸
(5)
Page | 45
4.2.3. Using Indoor Air with Heat Recovery to Alter Source Temperature
Indoor Air with
Heat Recovery
Outdoor
Air
Expansion Valve
Air Mixer
Evaporator
Compressor
Condenser
Figure 17. Using indoor air and heat recovery to alter temperature of outdoor air supply
As before, the schematic shown in Figure 17 is a theoretical configuration, this time
showing that the air source heat pump was again fed by both the outdoor and indoor
air, however the indoor air was provided through a heat recovery system. Once again,
for the purposes of these calculations it was assumed that the room had already reached
temperature in order to isolate the effect which the outdoor temperature has on the COP.
The impact of the indoor air vented via the heat recovery system on the outdoor air
supply had to be taken into account which resulted in Equation (6), shown below:
𝑇𝑠𝑜𝑢𝑟𝑐𝑒 =
(𝑇𝑂 × (𝑄𝐸 − 𝑄𝐵 ) + ((𝑇𝐼 − 𝑇𝑂 ) × 𝐻𝑅𝐸𝑓𝑓 + 𝑇𝑂 ) × 𝑄𝐵 )
𝑄𝐸
(6)
Page | 46
4.2.4. Using Indoor Air and Waste Heat from Compressor to Alter Source
Temperature
Outdoor
Air
Indoor Air
Expansion Valve
Air Mixer
Evaporator
Compressor
Condenser
Figure 18. Using indoor air and waste heat from compressor to alter temperature of outdoor air supply
In Figure 18, the schematic shows a theoretical configuration of an air source heat pump
being fed by three sources; outdoor air, directly vented indoor air and waste heat from
the compressor. The waste heat from the compressor and the indoor air should both
cause the temperature of the outdoor air within the air mixer to increase before being
supplied to the evaporator unit.
Theoretically, upon start-up of the heat pump, the COP of the heat pump should be low,
before increasing as heat is generated in the compressor unit, whilst at the same time
the indoor temperature would start low and increase as the heating system stabilised the
temperature within the room. For the purposes of these calculations it was assumed that
the room had already reached temperature and the compressor was already up to
temperature. These assumptions isolated the effect which the outdoor temperature has
on the COP.
The impact of the indoor air and the waste heat from the compressor on the outdoor air
supply had to be taken into account which resulted in Equation (7), shown below:
Page | 47
𝑇𝑠𝑜𝑢𝑟𝑐𝑒 =
(𝑇𝑂 × (𝑄𝐸 − 𝑄𝐵 ) + 𝑇𝐼 × 𝑄𝐵 )
𝐸𝐶
+
𝑄𝐸
(𝑄𝐸 × 𝜌𝐴𝑖𝑟 × 𝐶𝐴𝑖𝑟 )
(7)
4.2.5. Using Indoor Air with Heat Recovery and Waste Heat from Compressor to
Alter Source Temperature
Outdoor
Air
Indoor Air with
Heat Recovery
Expansion Valve
Air Mixer
Evaporator
Compressor
Condenser
Figure 19. Using indoor air with heat recovery and waste heat from compressor to alter temperature of outdoor air
supply
In Figure 19, the schematic shows a theoretical configuration in which it can be seen
that the air source heat pump was fed by outdoor air, waste heat from the compressor
and indoor air from a heat recovery system. Once again, for the purposes of these
calculations it was assumed that both the room and compressor had already reached
temperature in order to isolate the effect which the outdoor temperature has on the COP.
In order to determine the source temperature entering the evaporator unit, a new
calculation had to be performed which took into account the impact of the indoor air
with heat recover and waste heat from the compressor on the outdoor air supply. The
equation used for this is shown in Equation (8), shown below:
Page | 48
𝑇𝑠𝑜𝑢𝑟𝑐𝑒 =
(𝑇𝑂 × (𝑄𝐸 − 𝑄𝐵 ) + ((𝑇𝐼 − 𝑇𝑂 ) × 𝐻𝑅𝐸𝑓𝑓 + 𝑇𝑂 ) × 𝑄𝐵 )
𝐸𝐶
+
𝑄𝐸
(𝑄𝐸 × 𝜌𝐴𝑖𝑟 × 𝐶𝐴𝑖𝑟 )
(8)
4.3. Results
4.3.1. Using Indoor Air to Alter Source Temperature
Table 7. Using indoor air to alter source temperature: results
Outdoor
Temperature (°C)
COP
Source
Temperature (°C)
New COP
COP Increase
Energy Consumption
-20
1.85
-16.19
1.97
7%
-7%
-15
2.22
-11.67
2.24
1%
-1%
-7
2.35
-4.43
2.85
21%
-18%
-2
2.96
0.10
3.35
13%
-12%
2
3.20
3.71
3.82
19%
-16%
7
4.63
8.24
4.48
-3%
3%
10
4.94
10.95
4.92
0%
0%
12
5.54
12.76
5.23
-6%
6%
15
5.55
15.48
5.73
3%
-3%
20
6.31
20.00
6.62
5%
-5%
7.00
6.00
5.00
COP
4.00
3.00
2.00
1.00
0.00
-25
-20
-15
-10
-5
0
5
10
15
20
25
Source Temperature (°C)
COP
New COP
Figure 20. Using indoor air to alter outdoor air temperature: graph
It can be seen from Table 7 and Figure 20 that directly venting the indoor air raise the
temperature of the outdoor air in the air mixer results in increases in COP at most
outdoor temperatures. The greatest increase in COP occurs at -7°C where a 21%
increase is achieved, which results in an approximate energy saving of 18%.
Similarly, high increases in COP are achieved between -2°C and 2°C, which also see
Page | 49
significant energy savings. There are some anomalies in the results at 7°C and 12°C,
showing a reduction in COP and therefore an increase in energy consumption. A
sample calculation is shown in full in Appendix H – Sample Heat Pump COP
Calculations
4.3.2. Using Indoor Air with Heat Recovery to Alter Source Temperature
Table 8. Using indoor air with heat recovery to alter source temperature: results
Outdoor
Temperature (°C)
COP
Source
Temperature (°C)
New COP
COP Increase
Energy Consumption
-20
1.85
-16.84
1.94
5%
-5%
-15
2.22
-12.23
2.20
-1%
1%
-7
2.35
-4.87
2.81
19%
-16%
-2
2.96
-0.26
3.31
12%
-11%
2
3.20
3.42
3.78
18%
-15%
7
4.63
8.03
4.45
-4%
4%
10
4.94
10.79
4.89
-1%
1%
12
5.54
12.63
5.21
-6%
6%
15
5.55
15.40
5.71
3%
-3%
20
6.31
20.00
6.62
5%
-5%
7.00
6.00
5.00
COP
4.00
3.00
2.00
1.00
0.00
-25
-20
-15
-10
-5
0
5
10
15
20
25
Source Temperature (°C)
COP
New COP
Figure 21. Using indoor air with heat recovery to alter source temperature: graph
Table 8 and Figure 21 show that whilst there are still increases in COP in most cases,
they are not as significant as those shown in Table 7. Where previously the increase in
COP at -7°C had been 21%, in this instance it was down to 19%, likewise the
increases at -2°C and 2°C were reduced to 12% and 18% respectively. Additionally,
Page | 50
the instances where the COP decreased increased to four where there had only been
two in Table 7. The maximum energy saving in the heat pump, achieved through
using heat recovery system to supply the indoor air was 16% which may be offset
slightly be the energy required to operate the heat recovery system itself. A sample
calculation is shown in full in Appendix H – Sample Heat Pump COP Calculations
4.3.3. Using Indoor Air with Waste Heat from Compressor to Alter Source
Temperature
Table 9. Using indoor air with waste heat from compressor to alter source temperature: results
Outdoor
Temperature (°C)
COP
Source
Temperature (°C)
New COP
COP Increase
Energy Consumption
8%
-7%
-20
1.85
-15.90
1.99
-15
2.22
-11.37
2.26
2%
-2%
-7
2.35
-4.14
2.88
23%
-18%
-2
2.96
0.39
3.39
15%
-13%
2
3.20
4.01
3.86
21%
-17%
7
4.63
8.53
4.53
-2%
2%
10
4.94
11.25
4.97
1%
-1%
12
5.54
13.05
5.29
-5%
5%
15
5.55
15.77
5.78
4%
-4%
20
6.31
20.29
6.69
6%
-6%
8.00
7.00
6.00
COP
5.00
4.00
3.00
2.00
1.00
0.00
-25
-20
-15
-10
-5
0
5
10
15
20
25
Source Temperature (°C)
COP
New COP
Figure 22. Using indoor air with waste heat from compressor to alter source temperature:
graph
It can be seen in Table 9 and Figure 22, above,
that using waste heat from the
compressor along with the directly vented indoor air causes the COP to increase more
Page | 51
than when only the directly vented indoor air is used. The largest COP increase, once
again at an outdoor temperature of -7°C, was 23% which was 2% greater than when
only the directly vented air was used as a low exergy thermal source. This 23% COP
increase still resulted in an 18% saving in energy which had been the maximum in
Table 7. Further COP increase worth noting were 15% at -2°C and 21% at 2°C. A
sample calculation is shown in full in Appendix H – Sample Heat Pump COP
Calculations
4.3.4. Using Indoor Air with Heat Recovery and Waste Heat from Compressor to
Alter Source Temperature
Table 10. Using indoor air with heat recovery and waste heat from compressor to alter source
temperature: results
Outdoor
Temperature (°C)
COP
Source
Temperature (°C)
New COP
COP Increase
Energy Consumption
-20
1.85
-16.55
1.96
6%
-6%
-15
2.22
-11.94
2.22
0%
0%
-7
2.35
-4.57
2.84
21%
-17%
-2
2.96
0.03
3.35
13%
-12%
2
3.20
3.72
3.82
19%
-16%
7
4.63
8.32
4.49
-3%
3%
10
4.94
11.08
4.94
0%
0%
12
5.54
12.93
5.26
-5%
5%
15
5.55
15.69
5.77
4%
-4%
20
6.31
20.29
6.69
6%
-6%
8.00
7.00
6.00
COP
5.00
4.00
3.00
2.00
1.00
0.00
-25
-20
-15
-10
-5
0
5
10
15
20
25
Source Temperature (°C)
Figure 23. Using indoor air with heat recovery
heat from compressor to alter source
COP and waste
New COP
temperature: results
Page | 52
Table 10 and Figure 23 indicate that once again the waste heat from the compressor
does improve the COP of the heat pump more than simply using the indoor air provided
through the heat recovery system. It appears from the COP increases achieved that by
coupling the waste heat from the compressor with indoor air provided by a heat
recovery system, the waste heat from the compressor acts to negate the heat lost through
the inefficiency of the heat recovery system. The maximum COP increase is 21%
followed by 13% and 19% which is line with the figures shown in Table 7. A sample
calculation is shown in full in Appendix H – Sample Heat Pump COP Calculations
4.4. Conclusion
It has been shown that using a heat recovery system to supply the indoor air to the air
mixer is less effective that venting the indoor air directly into the air mixer. Conversely
it was shown that using the waste heat from the compressor did lead to greater COP
increases than solely using indoor air.
The greatest increases in COP were achieved using directly vented indoor air and waste
heat from the compressor, with a maximum COP increase of 23% being achieved at an
outdoor air temperature of -7°C. Likewise at -2°C and 2°C there were COP increases
of 15% and 21% achieved respectively. It was interesting to note that from 7°C
upwards, the maximum COP increase achieved was 6% whilst there were also instances
where the COP decreased as opposed to increasing.
In terms of energy savings, naturally the greatest savings were achieved at the outdoor
air temperatures which had the largest COP increases. The greatest energy saving
calculated was 18% which occurred at the 21% COP increase. At the lowest registered
outdoor air temperature, -20°C, an 8% energy saving was calculated whilst at the
maximum outdoor temperature, 20°C, a 6% energy saving was calculated. It was
interesting to note that despite these savings being very close in value, the energy
savings in between the two temperature extremes varied greatly. The maximum energy
savings indicated in the results were all greater than savings shown in Figure 9 for
measures such as condensing boilers, loft insulation and cavity wall insulation.
Page | 53
5. Conclusion
It is possible to improve the coefficient of performance of heat pumps by utilising low
exergy thermal sources to increase the source temperature at the evaporator, however
there are many elements which will affect the extent to which the COP will be
increased. The sensitivity of the heat pump being used will greatly determine how much
scope there is for COP improvement, with results indicating that air-to-water heat
pumps can be up to twice as sensitive to changes in source temperature as air-to-air heat
pumps. It is also important to note that the temperature range at which the heat pump is
operating will have an effect on the sensitivity of the chosen heat pump. Some models
were more sensitive at lower source temperature whilst others were more sensitive in
the medium source temperature range.
Once a suitable heat pump has been chosen, another element which will affect the
potential to increase the COP of the heat pump is the way in which it is installed. Results
within this report indicated that it is more favourable to directly vent air from a heat
source to the evaporator unit as opposed to using a heat recovery system. It was also
indicated that installing the heat pump in a manner which used the waste heat from the
compressor to raise the source temperature was of additional benefit to the COP.
In the calculations performed in this report, the indoor air from the building along with
waste heat from the compressor were chosen as the low exergy sources used to raise
the source temperature of the heat pump, which resulted in a maximum COP increase
of 23%. Should a low exergy thermal source with a higher temperature be chosen, the
resulting COP increase could be greater, however changes in air flow rates within the
building, depending on the source used or the occupancy levels within the building,
may have additional effects on any potential COP increase. Some low exergy thermal
sources which may provide an appropriately high temperature are more readily found
in industrial or commercial buildings as opposed to domestic ones. Air extracted from
chiller units or boiler rooms are examples of sources which are unlikely to be found in
a regular dwelling.
When calculating the potential COP increases and corresponding energy savings for the
chosen heat pump, the calculations were only undertaken for individual source
Page | 54
temperatures. This range of temperatures was dictated by the information available in
the technical data sheet for the chosen heat pump. For a more accurate representation
of the potential increase in COP and energy savings over a length of time, in a realistic
range of temperature, the seasonal coefficient of performance of the heat pump should
be calculated as defined by EN 14825. The European Standard states that it is
mandatory to calculate the SCOP for the heat pump using the “average” climate of
Strasbourg. Given that the sensitivity study indicated that some heat pumps are more
sensitive in lower source temperature ranges, it is also suggested that the colder climate
of Helsinki also be used. For this report, the SCOP was unable to be calculated due to
some information being unavailable, such as various power settings of the heat pump
when in standby mode. These figures were unable to be sourced from the technical data
sheets available for the chosen heat pump.
The calculations within this report were theoretical in nature and provided a guideline
for the potential benefits of using low exergy thermal source to improve the COP of
heat pumps, however more work could be done. In future work, it is suggested that
dynamic simulations could be performed using a system such as TRNSYS in order to
give a more in-depth calculation of COP improvements. By utilising a computer system,
more detailed installations could be assessed over a sustained period of time, taking
into account the stochastic nature of some low exergy thermal sources within buildings.
It is also suggested that if sufficient time is available, manual testing of an actual heat
pump could be performed in a laboratory to determine the real impact of using low
exergy thermal sources to increase the source temperature.
Page | 55
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Appendices
Appendix A – Daikin Heat Pump Data
Table 11. Daikin heat pump unit specifications (Daikin, 2011)
Manufacturer
Series
Model Combination
Nominal
Heating
Capacity (kW)
Nominal
Power Input Heating (kW)
Daikin
VRV III
RXYQ5P9W1B + RXYQ-5P9
16
4
Daikin
VRV III
RXYQ5P9W1B + RXYQ-8P9
25
5.56
Daikin
VRV III
RXYQ5P9W1B + RXYQ-10P9
31.5
7.7
Daikin
VRV III
RXYQ5P9W1B + RXYQ-12P9
37.5
9.44
Daikin
VRV III
RXYQ5P9W1B + RXYQ-14P9
45
11.3
Daikin
VRV III
RXYQ5P9W1B + RXYQ-16P9
50
12.9
Daikin
VRV III
RXYQ5P9W1B + RXYQ-18P9
56.5
15.3
Table 12. Daikin temperature, heating capacity, power input and COP details (Daikin, 2011)
Series
Model Combination
Indoor Air
Temperature
(°C)
Outdoor Air
Temperature
(°C)
Heating
Capacity
(kW)
Power
Input
(kW)
COP
Carnot
COP
VRV III
RXYQ5P9W1B + RXYQ-5P9
20
-19.8
10.5
3.22
3.26
7.36
VRV III
RXYQ5P9W1B + RXYQ-5P9
20
-18.8
10.8
3.31
3.26
7.55
VRV III
RXYQ5P9W1B + RXYQ-5P9
20
-16.7
11.4
3.48
3.28
7.98
VRV III
RXYQ5P9W1B + RXYQ-5P9
20
-13.7
12
3.63
3.31
8.69
VRV III
RXYQ5P9W1B + RXYQ-5P9
20
-11.8
12.7
3.77
3.37
9.21
VRV III
RXYQ5P9W1B + RXYQ-5P9
20
-9.8
13.3
3.89
3.42
9.83
VRV III
RXYQ5P9W1B + RXYQ-5P9
20
-9.5
13.6
3.95
3.44
9.93
VRV III
RXYQ5P9W1B + RXYQ-5P9
20
-8.5
13.9
4
3.48
10.28
VRV III
RXYQ5P9W1B + RXYQ-5P9
20
-7
14.4
4.08
3.53
10.85
VRV III
RXYQ5P9W1B + RXYQ-5P9
20
-5
15
4.18
3.59
11.72
VRV III
RXYQ5P9W1B + RXYQ-5P9
20
-3
15.6
4.26
3.66
12.74
VRV III
RXYQ5P9W1B + RXYQ-5P9
20
0
16.5
4.38
3.77
14.65
VRV III
RXYQ5P9W1B + RXYQ-5P9
20
3
17.4
4.49
3.88
17.24
VRV III
RXYQ5P9W1B + RXYQ-5P9
20
5
18
4.55
3.96
19.53
VRV III
RXYQ5P9W1B + RXYQ-5P9
20
7
18.6
4.61
4.03
22.54
VRV III
RXYQ5P9W1B + RXYQ-5P9
20
9
19.2
4.67
4.11
26.64
VRV III
RXYQ5P9W1B + RXYQ-5P9
20
11
19.8
4.72
4.19
32.56
VRV III
RXYQ5P9W1B + RXYQ-5P9
20
13
20.4
4.78
4.27
41.86
VRV III
RXYQ5P9W1B + RXYQ-5P9
20
15
20.8
4.74
4.39
58.60
VRV III
RXYQ5P9W1B + RXYQ-8P9
20
-19.8
16.1
4.3
3.74
7.36
VRV III
RXYQ5P9W1B + RXYQ-8P9
20
-18.8
16.6
4.43
3.75
7.55
VRV III
RXYQ5P9W1B + RXYQ-8P9
20
-16.7
17.6
4.66
3.78
7.98
VRV III
RXYQ5P9W1B + RXYQ-8P9
20
-13.7
18.5
4.87
3.80
Page | 61
8.69
VRV III
RXYQ5P9W1B + RXYQ-8P9
20
-11.8
19.5
5.16
3.78
9.21
VRV III
RXYQ5P9W1B + RXYQ-8P9
20
-9.8
20.4
5.23
3.90
9.83
VRV III
RXYQ5P9W1B + RXYQ-8P9
20
-9.5
20.9
5.32
3.93
9.93
VRV III
RXYQ5P9W1B + RXYQ-8P9
20
-8.5
21.4
5.38
3.98
10.28
VRV III
RXYQ5P9W1B + RXYQ-8P9
20
-7
22.1
5.49
4.03
10.85
VRV III
RXYQ5P9W1B + RXYQ-8P9
20
-5
23
5.63
4.09
11.72
VRV III
RXYQ5P9W1B + RXYQ-8P9
20
-3
23.9
5.75
4.16
12.74
VRV III
RXYQ5P9W1B + RXYQ-8P9
20
0
25.4
5.92
4.29
14.65
VRV III
RXYQ5P9W1B + RXYQ-8P9
20
3
26.8
6.06
4.42
17.24
VRV III
RXYQ5P9W1B + RXYQ-8P9
20
5
27.7
6.15
4.50
19.53
VRV III
RXYQ5P9W1B + RXYQ-8P9
20
7
28.6
6.23
4.59
22.54
VRV III
RXYQ5P9W1B + RXYQ-8P9
20
9
29.5
6.31
4.68
26.64
VRV III
RXYQ5P9W1B + RXYQ-8P9
20
11
30.4
6.39
4.76
32.56
VRV III
RXYQ5P9W1B + RXYQ-8P9
20
13
31.4
6.46
4.86
41.86
VRV III
RXYQ5P9W1B + RXYQ-8P9
20
15
32.3
6.53
4.95
58.60
VRV III
RXYQ5P9W1B + RXYQ-10P9
20
-19.8
20.2
6.21
3.25
7.36
VRV III
RXYQ5P9W1B + RXYQ-10P9
20
-18.8
20.6
6.32
3.26
7.55
VRV III
RXYQ5P9W1B + RXYQ-10P9
20
-16.7
21.3
6.55
3.25
7.98
VRV III
RXYQ5P9W1B + RXYQ-10P9
20
-13.7
22.2
6.79
3.27
8.69
VRV III
RXYQ5P9W1B + RXYQ-10P9
20
-11.8
23.2
7.13
3.25
9.21
VRV III
RXYQ5P9W1B + RXYQ-10P9
20
-9.8
24.2
7.28
3.32
9.83
VRV III
RXYQ5P9W1B + RXYQ-10P9
20
-9.5
24.8
7.4
3.35
9.93
VRV III
RXYQ5P9W1B + RXYQ-10P9
20
-8.5
25.4
7.51
3.38
10.28
VRV III
RXYQ5P9W1B + RXYQ-10P9
20
-7
26.3
7.69
3.42
10.85
VRV III
RXYQ5P9W1B + RXYQ-10P9
20
-5
27.6
7.93
3.48
11.72
VRV III
RXYQ5P9W1B + RXYQ-10P9
20
-3
29
8.14
3.56
12.74
VRV III
RXYQ5P9W1B + RXYQ-10P9
20
0
31.3
8.47
3.70
14.65
VRV III
RXYQ5P9W1B + RXYQ-10P9
20
3
33.7
8.77
3.84
17.24
VRV III
RXYQ5P9W1B + RXYQ-10P9
20
5
35.5
8.95
3.97
19.53
VRV III
RXYQ5P9W1B + RXYQ-10P9
20
7
37.3
9.13
4.09
22.54
VRV III
RXYQ5P9W1B + RXYQ-10P9
20
9
39.2
9.29
4.22
26.64
VRV III
RXYQ5P9W1B + RXYQ-10P9
20
11
41
9.38
4.37
32.56
VRV III
RXYQ5P9W1B + RXYQ-10P9
20
13
41
8.79
4.66
41.86
VRV III
RXYQ5P9W1B + RXYQ-10P9
20
15
41
8.28
4.95
58.60
VRV III
RXYQ5P9W1B + RXYQ-12P9
20
-19.8
20.6
5.02
4.10
7.36
VRV III
RXYQ5P9W1B + RXYQ-12P9
20
-18.8
20.9
5.15
4.06
7.55
VRV III
RXYQ5P9W1B + RXYQ-12P9
20
-16.7
21
5.43
3.87
7.98
VRV III
RXYQ5P9W1B + RXYQ-12P9
20
-13.7
22.6
5.72
3.95
8.69
VRV III
RXYQ5P9W1B + RXYQ-12P9
20
-11.8
23.6
6.02
3.92
9.21
VRV III
RXYQ5P9W1B + RXYQ-12P9
20
-9.8
24.7
6.31
3.91
9.83
VRV III
RXYQ5P9W1B + RXYQ-12P9
20
-9.5
25.2
6.46
3.90
9.93
VRV III
RXYQ5P9W1B + RXYQ-12P9
20
-8.5
25.8
6.6
3.91
10.28
Page | 62
VRV III
RXYQ5P9W1B + RXYQ-12P9
20
-7
26.7
6.81
3.92
10.85
VRV III
RXYQ5P9W1B + RXYQ-12P9
20
-5
28.1
7.1
3.96
11.72
VRV III
RXYQ5P9W1B + RXYQ-12P9
20
-3
29.4
7.36
3.99
12.74
VRV III
RXYQ5P9W1B + RXYQ-12P9
20
0
31.8
7.75
4.10
14.65
VRV III
RXYQ5P9W1B + RXYQ-12P9
20
3
34.3
8.11
4.23
17.24
VRV III
RXYQ5P9W1B + RXYQ-12P9
20
5
36
8.33
4.32
19.53
VRV III
RXYQ5P9W1B + RXYQ-12P9
20
7
37.8
8.54
4.43
22.54
VRV III
RXYQ5P9W1B + RXYQ-12P9
20
9
39.7
8.73
4.55
26.64
VRV III
RXYQ5P9W1B + RXYQ-12P9
20
11
41.7
8.92
4.67
32.56
VRV III
RXYQ5P9W1B + RXYQ-12P9
20
13
43.9
9.1
4.82
41.86
VRV III
RXYQ5P9W1B + RXYQ-12P9
20
15
46.1
9.27
4.97
58.60
VRV III
RXYQ5P9W1B + RXYQ-14P9
20
-19.8
27.9
8.38
3.33
7.36
VRV III
RXYQ5P9W1B + RXYQ-14P9
20
-18.8
28.4
8.55
3.32
7.55
VRV III
RXYQ5P9W1B + RXYQ-14P9
20
-16.7
29.6
8.89
3.33
7.98
VRV III
RXYQ5P9W1B + RXYQ-14P9
20
-13.7
30.8
9.24
3.33
8.69
VRV III
RXYQ5P9W1B + RXYQ-14P9
20
-11.8
32.1
9.6
3.34
9.21
VRV III
RXYQ5P9W1B + RXYQ-14P9
20
-9.8
33.6
9.95
3.38
9.83
VRV III
RXYQ5P9W1B + RXYQ-14P9
20
-9.5
34.4
10.13
3.40
9.93
VRV III
RXYQ5P9W1B + RXYQ-14P9
20
-8.5
35.1
10.28
3.41
10.28
VRV III
RXYQ5P9W1B + RXYQ-14P9
20
-7
36.4
10.54
3.45
10.85
VRV III
RXYQ5P9W1B + RXYQ-14P9
20
-5
38.2
10.9
3.50
11.72
VRV III
RXYQ5P9W1B + RXYQ-14P9
20
-3
40.1
11.2
3.58
12.74
VRV III
RXYQ5P9W1B + RXYQ-14P9
20
0
43.2
11.6
3.72
14.65
VRV III
RXYQ5P9W1B + RXYQ-14P9
20
3
46.5
12.1
3.84
17.24
VRV III
RXYQ5P9W1B + RXYQ-14P9
20
5
48.8
12.3
3.97
19.53
VRV III
RXYQ5P9W1B + RXYQ-14P9
20
7
51.2
12.6
4.06
22.54
VRV III
RXYQ5P9W1B + RXYQ-14P9
20
9
53.7
12.8
4.20
26.64
VRV III
RXYQ5P9W1B + RXYQ-14P9
20
11
56.4
13
4.34
32.56
VRV III
RXYQ5P9W1B + RXYQ-14P9
20
13
58.5
12.9
4.53
41.86
VRV III
RXYQ5P9W1B + RXYQ-14P9
20
15
58.5
12.2
4.80
58.60
VRV III
RXYQ5P9W1B + RXYQ-16P9
20
-19.8
30.4
9.09
3.34
7.36
VRV III
RXYQ5P9W1B + RXYQ-16P9
20
-18.8
31
9.28
3.34
7.55
VRV III
RXYQ5P9W1B + RXYQ-16P9
20
-16.7
32.2
9.68
3.33
7.98
VRV III
RXYQ5P9W1B + RXYQ-16P9
20
-13.7
33.5
10.08
3.32
8.69
VRV III
RXYQ5P9W1B + RXYQ-16P9
20
-11.8
35
10.48
3.34
9.21
VRV III
RXYQ5P9W1B + RXYQ-16P9
20
-9.8
36.6
10.89
3.36
9.83
VRV III
RXYQ5P9W1B + RXYQ-16P9
20
-9.5
37.5
11.09
3.38
9.93
VRV III
RXYQ5P9W1B + RXYQ-16P9
20
-8.5
38.3
11.27
3.40
10.28
VRV III
RXYQ5P9W1B + RXYQ-16P9
20
-7
39.7
11.6
3.42
10.85
VRV III
RXYQ5P9W1B + RXYQ-16P9
20
-5
41.6
11.9
3.50
11.72
VRV III
RXYQ5P9W1B + RXYQ-16P9
20
-3
43.6
12.3
3.54
12.74
VRV III
RXYQ5P9W1B + RXYQ-16P9
20
0
47
12.8
3.67
14.65
Page | 63
VRV III
RXYQ5P9W1B + RXYQ-16P9
20
3
50.6
13.3
3.80
17.24
VRV III
RXYQ5P9W1B + RXYQ-16P9
20
5
53.1
13.6
3.90
19.53
VRV III
RXYQ5P9W1B + RXYQ-16P9
20
7
55.8
13.9
4.01
22.54
VRV III
RXYQ5P9W1B + RXYQ-16P9
20
9
58.5
14.1
4.15
26.64
VRV III
RXYQ5P9W1B + RXYQ-16P9
20
11
61.4
14.4
4.26
32.56
VRV III
RXYQ5P9W1B + RXYQ-16P9
20
13
64.5
14.6
4.42
41.86
VRV III
RXYQ5P9W1B + RXYQ-16P9
20
15
65
13.9
4.68
58.60
VRV III
RXYQ5P9W1B + RXYQ-18P9
20
-19.8
31.2
8.14
3.83
7.36
VRV III
RXYQ5P9W1B + RXYQ-18P9
20
-18.8
31.8
8.37
3.80
7.55
VRV III
RXYQ5P9W1B + RXYQ-18P9
20
-16.7
33
8.83
3.74
7.98
VRV III
RXYQ5P9W1B + RXYQ-18P9
20
-13.7
34.3
9.3
3.69
8.69
VRV III
RXYQ5P9W1B + RXYQ-18P9
20
-11.8
35.8
9.8
3.65
9.21
VRV III
RXYQ5P9W1B + RXYQ-18P9
20
-9.8
37.5
10.3
3.64
9.83
VRV III
RXYQ5P9W1B + RXYQ-18P9
20
-9.5
38.3
10.5
3.65
9.93
VRV III
RXYQ5P9W1B + RXYQ-18P9
20
-8.5
39.2
10.7
3.66
10.28
VRV III
RXYQ5P9W1B + RXYQ-18P9
20
-7
40.6
11.1
3.66
10.85
VRV III
RXYQ5P9W1B + RXYQ-18P9
20
-5
42.6
11.5
3.70
11.72
VRV III
RXYQ5P9W1B + RXYQ-18P9
20
-3
44.6
11.9
3.75
12.74
VRV III
RXYQ5P9W1B + RXYQ-18P9
20
0
48.1
12.6
3.82
14.65
VRV III
RXYQ5P9W1B + RXYQ-18P9
20
3
51.7
13.1
3.95
17.24
VRV III
RXYQ5P9W1B + RXYQ-18P9
20
5
54.3
13.5
4.02
19.53
VRV III
RXYQ5P9W1B + RXYQ-18P9
20
7
57
13.8
4.13
22.54
VRV III
RXYQ5P9W1B + RXYQ-18P9
20
9
59.8
14.2
4.21
26.64
VRV III
RXYQ5P9W1B + RXYQ-18P9
20
11
62.7
14.5
4.32
32.56
VRV III
RXYQ5P9W1B + RXYQ-18P9
20
13
65.9
14.8
4.45
41.86
VRV III
RXYQ5P9W1B + RXYQ-18P9
20
15
69.1
15
4.61
58.60
Appendix B – Worcester Bosch Heat Pump Data
Table 13. Worcester Bosch heat pump unit specifications (Worcester Bosch Group, 2013)
Manufacturer
Series
Model
Worcester Bosch
Greensource
7-716-150-179
Nominal Heating
Capacity (kW)
Nominal Power Input
- Heating (kW)
4
1.3
Page | 64
Table 14. Worcester Bosch Greensource Heating capacities, power inputs and COPs (Worcester Bosch
Group, 2013)
Indoor Air
Temperature (°C)
Outdoor Air
Temperature (°C)
Heating
Capacity (kW)
Power
Input (kW)
COP
Carnot
COP
20
-15
2.5
2.5
1.00
8.37
20
-7
3.2
2.5
1.28
10.85
20
2
3.5
2.5
1.40
16.28
20
7
4.7
2.5
1.88
22.54
Appendix C – Samsung Heat Pump Data
Table 15. Samsung heat pump unit specifications (Samsung, 2015)
Manufacturer
Series
Model Combination
Nominal
Heating
Capacity (kW)
Nominal
Power Input Heating (kW)
Samsung
Slim 1 Way Cassette
AC026FCADEH/EU + AC026FB1DEH/EU
4.6
1.3
Samsung
Slim 1 Way Cassette
AC035FCADEH/EU + AC035FB1DEH/EU
4.75
1.39
Samsung
Mini 4 Way Cassette
AC026FCADEH/EU + AC026FBNDEH/EU
4.6
1.4
Samsung
Mini 4 Way Cassette
AC035FCADEH/EU + AC035FBNDEH/EU
5
1.4
Samsung
Mini 4 Way Cassette
AC052FCADEH/EU + AC052FBNDEH/EU
7.5
2.4
Samsung
Mini 4 Way Cassette
AC060FCADEH/EU + AC060FBNDEH/EU
9
3.6
Samsung
Mini 4 Way Cassette
AC071FCADEH/EU + AC071FBNDEH/EU
10
3.8
Table 16. Samsung heating capacities, power inputs and COPs (Samsung, 2015)
Series
Slim 1 Way Cassette
Slim 1 Way Cassette
Slim 1 Way Cassette
Slim 1 Way Cassette
Slim 1 Way Cassette
Slim 1 Way Cassette
Slim 1 Way Cassette
Slim 1 Way Cassette
Mini 4 Way Cassette
Model Combination
AC026FCADEH/EU +
AC026FB1DEH/EU
AC026FCADEH/EU +
AC026FB1DEH/EU
AC026FCADEH/EU +
AC026FB1DEH/EU
AC026FCADEH/EU +
AC026FB1DEH/EU
AC035FCADEH/EU +
AC035FB1DEH/EU
AC035FCADEH/EU +
AC035FB1DEH/EU
AC035FCADEH/EU +
AC035FB1DEH/EU
AC035FCADEH/EU +
AC035FB1DEH/EU
AC026FCADEH/EU +
AC026FBNDEH/EU
Indoor Air
Temperature
(°C)
Outdoor Air
Temperature
(°C)
Heating
Capacity
(kW)
Power
Input
(kW)
COP
Carnot
COP
20
-15
2.31
1.1
2.10
8.37
20
-10
2.72
1.07
2.54
9.77
20
7
3.3
0.91
3.63
22.54
20
24
3.52
0.96
3.67
-73.25
20
-15
2.51
1.41
1.78
8.37
20
-10
3.31
1.38
2.40
9.77
20
7
4
1.16
3.45
22.54
20
24
4.2
1.24
3.39
-73.25
20
-15
2.32
1.05
2.21
8.37
Page | 65
Mini 4 Way Cassette
Mini 4 Way Cassette
Mini 4 Way Cassette
Mini 4 Way Cassette
Mini 4 Way Cassette
Mini 4 Way Cassette
Mini 4 Way Cassette
Mini 4 Way Cassette
Mini 4 Way Cassette
Mini 4 Way Cassette
Mini 4 Way Cassette
Mini 4 Way Cassette
Mini 4 Way Cassette
Mini 4 Way Cassette
Mini 4 Way Cassette
Mini 4 Way Cassette
Mini 4 Way Cassette
Mini 4 Way Cassette
Mini 4 Way Cassette
AC026FCADEH/EU +
AC026FBNDEH/EU
AC026FCADEH/EU +
AC026FBNDEH/EU
AC026FCADEH/EU +
AC026FBNDEH/EU
AC035FCADEH/EU +
AC035FBNDEH/EU
AC035FCADEH/EU +
AC035FBNDEH/EU
AC035FCADEH/EU +
AC035FBNDEH/EU
AC035FCADEH/EU +
AC035FBNDEH/EU
AC052FCADEH/EU +
AC052FBNDEH/EU
AC052FCADEH/EU +
AC052FBNDEH/EU
AC052FCADEH/EU +
AC052FBNDEH/EU
AC052FCADEH/EU +
AC052FBNDEH/EU
AC060FCADEH/EU +
AC060FBNDEH/EU
AC060FCADEH/EU +
AC060FBNDEH/EU
AC060FCADEH/EU +
AC060FBNDEH/EU
AC060FCADEH/EU +
AC060FBNDEH/EU
AC071FCADEH/EU +
AC071FBNDEH/EU
AC071FCADEH/EU +
AC071FBNDEH/EU
AC071FCADEH/EU +
AC071FBNDEH/EU
AC071FCADEH/EU +
AC071FBNDEH/EU
20
-10
2.65
1.1
2.41
9.77
20
7
3.3
0.9
3.67
22.54
20
24
4.11
1.02
4.03
-73.25
20
-15
2.41
1.12
2.15
8.37
20
-10
3.02
1.25
2.42
9.77
20
7
4.02
1.11
3.62
22.54
20
24
4.98
1.5
3.32
-73.25
20
-15
4.2
2.05
2.05
8.37
20
-10
4.58
1.91
2.40
9.77
20
7
5.5
1.52
3.62
22.54
20
24
6.25
1.54
4.06
-73.25
20
-15
5.15
2.84
1.81
8.37
20
-10
6.02
2.82
2.13
9.77
20
7
7
2.18
3.21
22.54
20
24
8.25
2.25
3.67
-73.25
20
-15
4.86
2.78
1.75
8.37
20
-10
6.1
2.91
2.10
9.77
20
7
7.5
2.32
3.23
22.54
20
24
7.8
2.15
3.63
-73.25
Appendix D – Kingspan Heat Pump Data
Table 17. Kingspan heat pump unit specification (Kingspan, 2011)
Manufacturer
Series
Model
Nominal Heating
Capacity (kW)
Nominal Power Input
- Heating (kW)
Kingspan
Aeromax Plus
4kW
4.1
1.01
Kingspan
Aeromax Plus
6kW
5.8
1.37
Kingspan
Aeromax Plus
8kW
7.2
1.82
Kingspan
Aeromax Plus
12kW
11.9
3.01
Kingspan
Aeromax Plus
15kW
14.5
3.57
Page | 66
Table 18. Kingspan heating capacities, power inputs and COPs (Kingspan, 2011)
Series
Model
Output Water
Temperature
(°C)
Outdoor Air
Temperature
(°C)
Heating
Capacity
(kW)
Power
Input
(kW)
COP
Carnot
COP
Aeromax Plus
4kW
35
-3
3.01
0.97
3.09
8.11
Aeromax Plus
4kW
35
0
3.26
1.03
3.15
8.80
Aeromax Plus
4kW
35
2
3.5
1.13
3.10
9.33
Aeromax Plus
4kW
35
7
4.1
1.01
4.06
11.00
Aeromax Plus
6kW
35
-3
3.67
1.25
2.93
8.11
Aeromax Plus
6kW
35
0
3.98
1.34
2.98
8.80
Aeromax Plus
6kW
35
2
4.19
1.36
3.08
9.33
Aeromax Plus
6kW
35
7
5.81
1.38
4.22
11.00
Aeromax Plus
8kW
35
-3
4.73
1.68
2.81
8.11
Aeromax Plus
8kW
35
0
5.14
1.74
2.95
8.80
Aeromax Plus
8kW
35
2
5.41
1.80
3.00
9.33
Aeromax Plus
8kW
35
7
7.19
1.83
3.92
11.00
Aeromax Plus
12kW
35
-3
7.8
2.71
2.88
8.11
Aeromax Plus
12kW
35
0
8.47
2.80
3.02
8.80
Aeromax Plus
12kW
35
2
8.72
2.79
3.13
9.33
Aeromax Plus
12kW
35
7
11.8
2.97
3.98
11.00
Aeromax Plus
15kW
35
-3
9.06
3.18
2.85
8.11
Aeromax Plus
15kW
35
0
9.81
3.19
3.08
8.80
Aeromax Plus
15kW
35
2
10.2
3.19
3.20
9.33
Aeromax Plus
15kW
35
7
14.5
3.57
4.06
11.00
Appendix E – Toshiba Heat Pump Data
Table 19. Toshiba heat pump unit specifications (Toshiba, 2010b)
Nominal Heating
Capacity (kW)
Nominal Power Input
- Heating (kW)
8
1.82
HWS-1103H-E + HWS-1403XWH**-E
11.2
2.35
HWS-1403H-E + HWS-1403XWH**-E
14
3.11
Manufacturer
Series
Model Combination
Toshiba
Estia
HWS-803H-E + HWS-803XWH**-E
Toshiba
Estia
Toshiba
Estia
Table 20. Toshiba heating capacities, power inputs and COPs (Toshiba, 2010b)
Series
Model Combination
Output Water
Temperature
(°C)
Outdoor Air
Temperature
(°C)
Heating
Capacity
(kW)
Power
Input
(kW)
COP
Carnot
COP
1.82
2.10
5.60
Estia
HWS-803H-E + HWS-803XWH**-E
35
-20
3.83
Estia
HWS-803H-E + HWS-803XWH**-E
35
-15
4.54
1.9
2.39
6.16
Estia
HWS-803H-E + HWS-803XWH**-E
35
-7
5.3
2.21
2.40
7.33
Page | 67
Estia
HWS-803H-E + HWS-803XWH**-E
35
-2
6.11
2.26
2.70
8.32
Estia
HWS-803H-E + HWS-803XWH**-E
35
2
6.75
2.28
2.96
9.33
Estia
HWS-803H-E + HWS-803XWH**-E
35
7
8.78
2.07
4.24
11.00
Estia
HWS-803H-E + HWS-803XWH**-E
35
10
9.29
2.03
4.58
12.32
Estia
HWS-803H-E + HWS-803XWH**-E
35
12
9.81
2.02
4.86
13.39
Estia
HWS-803H-E + HWS-803XWH**-E
35
15
10.6
2.02
5.25
15.40
Estia
HWS-803H-E + HWS-803XWH**-E
35
20
11.99
2.01
5.97
20.53
Estia
HWS-1103H-E + HWS-1403XWH**-E
35
-20
5.48
2.97
1.85
5.60
Estia
HWS-1103H-E + HWS-1403XWH**-E
35
-15
6.86
3.09
2.22
6.16
Estia
HWS-1103H-E + HWS-1403XWH**-E
35
-7
8
3.4
2.35
7.33
Estia
HWS-1103H-E + HWS-1403XWH**-E
35
-2
9.9
3.35
2.96
8.32
Estia
HWS-1103H-E + HWS-1403XWH**-E
35
2
10.55
3.3
3.20
9.33
Estia
HWS-1103H-E + HWS-1403XWH**-E
35
7
14.97
3.23
4.63
11.00
Estia
HWS-1103H-E + HWS-1403XWH**-E
35
10
15.87
3.21
4.94
12.32
Estia
HWS-1103H-E + HWS-1403XWH**-E
35
12
16.62
3
5.54
13.39
Estia
HWS-1103H-E + HWS-1403XWH**-E
35
15
17.7
3.19
5.55
15.40
Estia
HWS-1103H-E + HWS-1403XWH**-E
35
20
20.01
3.17
6.31
20.53
Estia
HWS-1403H-E + HWS-1403XWH**-E
35
-20
6.18
3.5
1.77
5.60
Estia
HWS-1403H-E + HWS-1403XWH**-E
35
-15
7.94
3.69
2.15
6.16
Estia
HWS-1403H-E + HWS-1403XWH**-E
35
-7
9.37
4.1
2.29
7.33
Estia
HWS-1403H-E + HWS-1403XWH**-E
35
-2
10.93
4.04
2.71
8.32
Estia
HWS-1403H-E + HWS-1403XWH**-E
35
2
11.56
3.98
2.90
9.33
Estia
HWS-1403H-E + HWS-1403XWH**-E
35
7
17.08
3.94
4.34
11.00
Estia
HWS-1403H-E + HWS-1403XWH**-E
35
10
17.93
3.94
4.55
12.32
Estia
HWS-1403H-E + HWS-1403XWH**-E
35
12
18.96
3.95
4.80
13.39
Estia
HWS-1403H-E + HWS-1403XWH**-E
35
15
20.09
3.98
5.05
15.40
Estia
HWS-1403H-E + HWS-1403XWH**-E
35
20
21.87
3.75
5.83
20.53
Appendix F – Extrapolated Heat Pump Data
Table 21. Extrapolated COP figures
Sink
Temperature
(°C)
Source
Temperature
(°C)
Temperature
Difference
(ΔT)
D1
20
-19.8
39.8
10.5
D1
20
-18.8
38.8
D1
20
-16.7
36.7
D1
20
-15
35
D1
20
-13.7
33.7
12
D1
20
-11.8
31.8
12.7
D1
20
-10
10
ID Tag
Heating
Capacity
(kW)
Power
Input
(kW)
COP
Carnot
COP
3.22
3.26
7.36
10.8
3.31
3.26
7.55
11.4
3.48
3.28
7.98
3.29
8.37
3.63
3.31
8.69
3.77
3.37
9.21
3.39
29.30
Page | 68
D1
20
-9.8
29.8
13.3
3.89
3.42
9.83
D1
20
-9.5
29.5
13.6
3.95
3.44
9.93
D1
20
-8.5
28.5
13.9
4
3.48
10.28
D1
20
-7
27
14.4
4.08
3.53
10.85
D1
20
-5
25
15
4.18
3.59
11.72
D1
20
-3
23
15.6
4.26
3.66
12.74
D1
20
-2
22
3.71
13.32
D1
20
0
20
3.77
14.65
D1
20
2
18
3.82
16.28
D1
20
3
17
17.4
4.49
3.88
17.24
D1
20
5
15
18
4.55
3.96
19.53
D1
20
7
13
18.6
4.61
4.03
22.54
D1
20
9
11
19.2
4.67
4.11
26.64
D1
20
10
10
4.15
29.30
D1
20
11
9
4.19
32.56
D1
20
12
8
4.23
36.63
D1
20
13
7
20.4
4.78
4.27
41.86
D1
20
15
5
20.8
4.74
4.39
58.60
D2
20
-19.8
39.8
16.1
4.3
3.74
7.36
D2
20
-18.8
38.8
16.6
4.43
3.75
7.55
D2
20
-16.7
36.7
17.6
4.66
3.78
7.98
D2
20
-15
35
3.79
8.37
D2
20
-13.7
33.7
18.5
4.87
3.80
8.69
D2
20
-11.8
31.8
19.5
5.16
3.78
9.21
D2
20
-10
30
3.84
9.77
D2
20
-9.8
29.8
20.4
5.23
3.90
9.83
D2
20
-9.5
29.5
20.9
5.32
3.93
9.93
D2
20
-8.5
28.5
21.4
5.38
3.98
10.28
D2
20
-7
27
22.1
5.49
4.03
10.85
D2
20
-5
25
23
5.63
4.09
11.72
D2
20
-3
23
23.9
5.75
4.16
12.74
D2
20
-2
22
4.22
13.32
D2
20
0
20
4.29
14.65
D2
20
2
18
4.36
16.28
D2
20
3
17
26.8
6.06
4.42
17.24
D2
20
5
15
27.7
6.15
4.50
19.53
D2
20
7
13
28.6
6.23
4.59
22.54
D2
20
9
11
29.5
6.31
4.68
26.64
D2
20
10
10
4.72
29.30
D2
20
11
9
30.4
6.39
4.76
32.56
D2
20
12
8
4.81
36.63
D2
20
13
7
4.86
41.86
16.5
19.8
25.4
31.4
4.38
4.72
5.92
6.46
Page | 69
D2
20
15
5
32.3
6.53
4.95
58.60
D3
20
-19.8
39.8
20.2
6.21
3.25
7.36
D3
20
-18.8
38.8
20.6
6.32
3.26
7.55
D3
20
-16.7
36.7
21.3
6.55
3.25
7.98
D3
20
-15
35
3.26
8.37
D3
20
-13.7
33.7
22.2
6.79
3.27
8.69
D3
20
-11.8
31.8
23.2
7.13
3.25
9.21
D3
20
-10
30
3.29
9.77
D3
20
-9.8
29.8
24.2
7.28
3.32
9.83
D3
20
-9.5
29.5
24.8
7.4
3.35
9.93
D3
20
-8.5
28.5
25.4
7.51
3.38
10.28
D3
20
-7
27
26.3
7.69
3.42
10.85
D3
20
-5
25
27.6
7.93
3.48
11.72
D3
20
-3
23
29
8.14
3.56
12.74
D3
20
-2
22
3.63
13.32
D3
20
0
20
31.3
8.47
3.70
14.65
D3
20
2
18
3.77
16.28
D3
20
3
17
33.7
8.77
3.84
17.24
D3
20
5
15
35.5
8.95
3.97
19.53
D3
20
7
13
37.3
9.13
4.09
22.54
D3
20
9
11
39.2
9.29
4.22
26.64
D3
20
10
10
4.30
29.30
D3
20
11
9
41
9.38
4.37
32.56
D3
20
12
8
4.52
36.63
D3
20
13
7
41
8.79
4.66
41.86
D3
20
15
5
41
8.28
4.95
58.60
D4
20
-19.8
39.8
20.6
5.02
4.10
7.36
D4
20
-18.8
38.8
20.9
5.15
4.06
7.55
D4
20
-16.7
36.7
21
5.43
3.87
7.98
D4
20
-15
35
3.91
8.37
D4
20
-13.7
33.7
22.6
5.72
3.95
8.69
D4
20
-11.8
31.8
23.6
6.02
3.92
9.21
D4
20
-10
30
3.92
9.77
D4
20
-9.8
29.8
24.7
6.31
3.91
9.83
D4
20
-9.5
29.5
25.2
6.46
3.90
9.93
D4
20
-8.5
28.5
25.8
6.6
3.91
10.28
D4
20
-7
27
26.7
6.81
3.92
10.85
D4
20
-5
25
28.1
7.1
3.96
11.72
D4
20
-3
23
29.4
7.36
3.99
12.74
D4
20
-2
22
4.05
13.32
D4
20
0
20
4.10
14.65
D4
20
2
18
4.17
16.28
31.8
7.75
Page | 70
D4
20
3
17
34.3
8.11
4.23
17.24
D4
20
5
15
36
8.33
4.32
19.53
D4
20
7
13
37.8
8.54
4.43
22.54
D4
20
9
11
39.7
8.73
4.55
26.64
D4
20
10
10
4.61
29.30
D4
20
11
9
4.67
32.56
D4
20
12
8
4.75
36.63
D4
20
13
7
43.9
9.1
4.82
41.86
D4
20
15
5
46.1
9.27
4.97
58.60
D5
20
-19.8
39.8
27.9
8.38
3.33
7.36
D5
20
-18.8
38.8
28.4
8.55
3.32
7.55
D5
20
-16.7
36.7
29.6
8.89
3.33
7.98
D5
20
-15
35
3.33
8.37
D5
20
-13.7
33.7
30.8
9.24
3.33
8.69
D5
20
-11.8
31.8
32.1
9.6
3.34
9.21
D5
20
-10
30
3.36
9.77
D5
20
-9.8
29.8
33.6
9.95
3.38
9.83
D5
20
-9.5
29.5
34.4
10.13
3.40
9.93
D5
20
-8.5
28.5
35.1
10.28
3.41
10.28
D5
20
-7
27
36.4
10.54
3.45
10.85
D5
20
-5
25
38.2
10.9
3.50
11.72
D5
20
-3
23
40.1
11.2
3.58
12.74
D5
20
-2
22
3.65
13.32
D5
20
0
20
3.72
14.65
D5
20
2
18
3.78
16.28
D5
20
3
17
46.5
12.1
3.84
17.24
D5
20
5
15
48.8
12.3
3.97
19.53
D5
20
7
13
51.2
12.6
4.06
22.54
D5
20
9
11
53.7
12.8
4.20
26.64
D5
20
10
10
4.27
29.30
D5
20
11
9
56.4
13
4.34
32.56
D5
20
12
8
4.44
36.63
D5
20
13
7
58.5
12.9
4.53
41.86
D5
20
15
5
58.5
12.2
4.80
58.60
D6
20
-19.8
39.8
30.4
9.09
3.34
7.36
D6
20
-18.8
38.8
31
9.28
3.34
7.55
D6
20
-16.7
36.7
32.2
9.68
3.33
7.98
D6
20
-15
35
3.32
8.37
D6
20
-13.7
33.7
33.5
10.08
3.32
8.69
D6
20
-11.8
31.8
35
10.48
3.34
9.21
D6
20
-10
30
3.35
9.77
D6
20
-9.8
29.8
3.36
9.83
41.7
43.2
36.6
8.92
11.6
10.89
Page | 71
D6
20
-9.5
29.5
37.5
11.09
3.38
9.93
D6
20
-8.5
28.5
38.3
11.27
3.40
10.28
D6
20
-7
27
39.7
11.6
3.42
10.85
D6
20
-5
25
41.6
11.9
3.50
11.72
D6
20
-3
23
43.6
12.3
3.54
12.74
D6
20
-2
22
3.61
13.32
D6
20
0
20
47
12.8
3.67
14.65
D6
20
2
18
3.74
16.28
D6
20
3
17
50.6
13.3
3.80
17.24
D6
20
5
15
53.1
13.6
3.90
19.53
D6
20
7
13
55.8
13.9
4.01
22.54
D6
20
9
11
58.5
14.1
4.15
26.64
D6
20
10
10
4.21
29.30
D6
20
11
9
4.26
32.56
D6
20
12
8
D6
20
13
D6
20
D7
61.4
14.4
4.34
36.63
7
64.5
14.6
4.42
41.86
15
5
65
13.9
4.68
58.60
20
-19.8
39.8
31.2
8.14
3.83
7.36
D7
20
-18.8
38.8
31.8
8.37
3.80
7.55
D7
20
-16.7
36.7
33
8.83
3.74
7.98
D7
20
-15
35
3.71
8.37
D7
20
-13.7
33.7
34.3
9.3
3.69
8.69
D7
20
-11.8
31.8
35.8
9.8
3.65
9.21
D7
20
-10
30
3.65
9.77
D7
20
-9.8
29.8
37.5
10.3
3.64
9.83
D7
20
-9.5
29.5
38.3
10.5
3.65
9.93
D7
20
-8.5
28.5
39.2
10.7
3.66
10.28
D7
20
-7
27
40.6
11.1
3.66
10.85
D7
20
-5
25
42.6
11.5
3.70
11.72
D7
20
-3
23
44.6
11.9
3.75
12.74
D7
20
-2
22
3.78
13.32
D7
20
0
20
3.82
14.65
D7
20
2
18
3.88
16.28
D7
20
3
17
51.7
13.1
3.95
17.24
D7
20
5
15
54.3
13.5
4.02
19.53
D7
20
7
13
57
13.8
4.13
22.54
D7
20
9
11
59.8
14.2
4.21
26.64
D7
20
10
10
4.27
29.30
D7
20
11
9
4.32
32.56
D7
20
12
8
4.39
36.63
D7
20
13
7
65.9
14.8
4.45
41.86
D7
20
15
5
69.1
15
4.61
58.60
48.1
62.7
12.6
14.5
Page | 72
K1
35
-3
38
3.01
3.09
8.11
K1
35
-2
37
3.12
8.32
K1
35
0
35
3.26
1.034921
3.15
8.80
K1
35
2
33
3.5
1.129032
3.10
9.33
K1
35
3
32
3.34
9.63
K1
35
5
30
K1
35
7
28
4.1
1.009852
3.82
10.27
4.06
11.00
K2
35
-3
38
3.67
1.25256
2.93
8.11
K2
35
-2
37
2.96
8.32
K2
35
0
35
3.98
1.33557
2.98
8.80
K2
35
2
33
4.19
1.36039
3.08
9.33
K2
35
3
32
3.37
9.63
K2
35
5
30
3.94
10.27
K2
35
7
28
5.81
1.376777
4.22
11.00
K3
35
-3
38
4.73
1.683274
2.81
8.11
K3
35
-2
37
2.88
8.32
K3
35
0
35
5.14
1.742373
2.95
8.80
K3
35
2
33
5.41
1.803333
3.00
9.33
K3
35
3
32
3.23
9.63
K3
35
5
30
3.69
10.27
K3
35
7
28
7.19
1.834184
3.92
11.00
K4
35
-3
38
7.8
2.708333
2.88
8.11
K4
35
-2
37
2.95
8.32
K4
35
0
35
8.47
2.804636
3.02
8.80
K4
35
2
33
8.72
2.785942
3.13
9.33
K4
35
3
32
3.34
9.63
K4
35
5
30
3.77
10.27
K4
35
7
28
11.82
2.969849
3.98
11.00
K5
35
-3
38
9.06
3.178947
2.85
8.11
K5
35
-2
37
2.97
8.32
K5
35
0
35
9.81
3.185065
3.08
8.80
K5
35
2
33
10.2
3.1875
3.20
9.33
K5
35
3
32
3.42
9.63
K5
35
5
30
3.85
10.27
K5
35
7
28
14.5
3.571429
4.06
11.00
S1
20
-15
35
2.31
1.1
2.10
8.37
S1
20
-13.7
33.7
2.21
8.69
S1
20
-11.8
31.8
2.43
9.21
S1
20
-10
30
2.54
9.77
S1
20
-9.8
29.8
2.68
9.83
S1
20
-9.5
29.5
2.75
9.93
S1
20
-8.5
28.5
2.81
10.28
2.72
0.97411
1.07
Page | 73
S1
20
-7
27
2.88
10.85
S1
20
-5
25
3.02
11.72
S1
20
-3
23
3.08
12.74
S1
20
-2
22
3.22
13.32
S1
20
0
20
3.29
14.65
S1
20
2
18
3.36
16.28
S1
20
3
17
3.42
17.24
S1
20
5
15
3.56
19.53
S1
20
7
13
3.63
22.54
S1
20
9
11
3.63
26.64
S1
20
10
10
3.64
29.30
S1
20
11
9
3.64
32.56
S1
20
12
8
3.65
36.63
S1
20
13
7
3.65
41.86
S1
20
15
5
3.66
58.60
S1
20
20
0
3.66
#DIV/0!
S1
20
24
4
3.52
0.96
3.67
73.25
S2
20
-15
35
2.51
1.41
1.78
8.37
S2
20
-13.7
33.7
1.93
8.69
S2
20
-11.8
31.8
2.24
9.21
S2
20
-10
30
2.40
9.77
S2
20
-9.8
29.8
2.53
9.83
S2
20
-9.5
29.5
2.60
9.93
S2
20
-8.5
28.5
2.66
10.28
S2
20
-7
27
2.73
10.85
S2
20
-5
25
2.86
11.72
S2
20
-3
23
2.92
12.74
S2
20
-2
22
3.05
13.32
S2
20
0
20
3.12
14.65
S2
20
2
18
3.19
16.28
S2
20
3
17
3.25
17.24
S2
20
5
15
3.38
19.53
S2
20
7
13
3.45
22.54
S2
20
9
11
3.44
26.64
S2
20
10
10
3.43
29.30
S2
20
11
9
3.43
32.56
S2
20
12
8
3.42
36.63
S2
20
13
7
3.41
41.86
S2
20
15
5
3.40
58.60
S2
20
20
0
3.39
#DIV/0!
S2
20
24
4
4.2
1.24
3.39
73.25
S3
20
-15
35
2.32
1.05
2.21
8.37
3.3
3.31
4
0.91
1.38
1.16
Page | 74
S3
20
-13.7
33.7
2.26
8.69
S3
20
-11.8
31.8
2.36
9.21
S3
20
-10
30
2.41
9.77
S3
20
-9.8
29.8
2.57
9.83
S3
20
-9.5
29.5
2.64
9.93
S3
20
-8.5
28.5
2.72
10.28
S3
20
-7
27
2.80
10.85
S3
20
-5
25
2.96
11.72
S3
20
-3
23
3.04
12.74
S3
20
-2
22
3.20
13.32
S3
20
0
20
3.27
14.65
S3
20
2
18
3.35
16.28
S3
20
3
17
3.43
17.24
S3
20
5
15
3.59
19.53
S3
20
7
13
3.67
22.54
S3
20
9
11
3.71
26.64
S3
20
10
10
3.76
29.30
S3
20
11
9
3.80
32.56
S3
20
12
8
3.85
36.63
S3
20
13
7
3.89
41.86
S3
20
15
5
3.94
58.60
S3
20
20
0
3.98
#DIV/0!
S3
20
24
4
4.11
1.02
4.03
73.25
S4
20
-15
35
2.41
1.12
2.15
8.37
S4
20
-13.7
33.7
2.22
8.69
S4
20
-11.8
31.8
2.35
9.21
S4
20
-10
30
2.42
9.77
S4
20
-9.8
29.8
2.57
9.83
S4
20
-9.5
29.5
2.64
9.93
S4
20
-8.5
28.5
2.72
10.28
S4
20
-7
27
2.79
10.85
S4
20
-5
25
2.94
11.72
S4
20
-3
23
3.02
12.74
S4
20
-2
22
3.17
13.32
S4
20
0
20
3.24
14.65
S4
20
2
18
3.32
16.28
S4
20
3
17
3.40
17.24
S4
20
5
15
3.55
19.53
S4
20
7
13
3.62
22.54
S4
20
9
11
3.58
26.64
S4
20
10
10
3.55
29.30
S4
20
11
9
3.51
32.56
2.65
3.3
3.02
4.02
1.1
0.9
1.25
1.11
Page | 75
S4
20
12
8
3.47
36.63
S4
20
13
7
3.43
41.86
S4
20
15
5
3.40
58.60
S4
20
20
0
3.36
#DIV/0!
S4
20
24
4
4.98
1.5
3.32
73.25
S5
20
-15
35
4.2
2.05
2.05
8.37
S5
20
-13.7
33.7
2.14
8.69
S5
20
-11.8
31.8
2.31
9.21
S5
20
-10
30
2.40
9.77
S5
20
-9.8
29.8
2.55
9.83
S5
20
-9.5
29.5
2.63
9.93
S5
20
-8.5
28.5
2.70
10.28
S5
20
-7
27
2.78
10.85
S5
20
-5
25
2.93
11.72
S5
20
-3
23
3.01
12.74
S5
20
-2
22
3.16
13.32
S5
20
0
20
3.24
14.65
S5
20
2
18
3.31
16.28
S5
20
3
17
3.39
17.24
S5
20
5
15
3.54
19.53
S5
20
7
13
3.62
22.54
S5
20
9
11
3.67
26.64
S5
20
10
10
3.73
29.30
S5
20
11
9
3.78
32.56
S5
20
12
8
3.84
36.63
S5
20
13
7
3.89
41.86
S5
20
15
5
3.95
58.60
S5
20
20
0
4.00
#DIV/0!
S5
20
24
4
6.25
1.54
4.06
73.25
S6
20
-15
35
5.15
2.84
1.81
8.37
S6
20
-13.7
33.7
1.89
8.69
S6
20
-11.8
31.8
2.05
9.21
S6
20
-10
30
2.13
9.77
S6
20
-9.8
29.8
2.27
9.83
S6
20
-9.5
29.5
2.34
9.93
S6
20
-8.5
28.5
2.40
10.28
S6
20
-7
27
2.47
10.85
S6
20
-5
25
2.61
11.72
S6
20
-3
23
2.67
12.74
S6
20
-2
22
2.81
13.32
S6
20
0
20
2.87
14.65
S6
20
2
18
2.94
16.28
4.58
5.5
6.02
1.91
1.52
2.82
Page | 76
S6
20
3
17
3.01
17.24
S6
20
5
15
3.14
19.53
S6
20
7
13
3.21
22.54
S6
20
9
11
3.27
26.64
S6
20
10
10
3.32
29.30
S6
20
11
9
3.38
32.56
S6
20
12
8
3.44
36.63
S6
20
13
7
3.50
41.86
S6
20
15
5
3.55
58.60
S6
20
20
0
3.61
#DIV/0!
S6
20
24
4
8.25
2.25
3.67
73.25
S7
20
-15
35
4.86
2.78
1.75
8.37
S7
20
-13.7
33.7
1.84
8.69
S7
20
-11.8
31.8
2.01
9.21
S7
20
-10
30
2.10
9.77
S7
20
-9.8
29.8
2.24
9.83
S7
20
-9.5
29.5
2.31
9.93
S7
20
-8.5
28.5
2.38
10.28
S7
20
-7
27
2.45
10.85
S7
20
-5
25
2.59
11.72
S7
20
-3
23
2.66
12.74
S7
20
-2
22
2.81
13.32
S7
20
0
20
2.88
14.65
S7
20
2
18
2.95
16.28
S7
20
3
17
3.02
17.24
S7
20
5
15
3.16
19.53
S7
20
7
13
3.23
22.54
S7
20
9
11
3.28
26.64
S7
20
10
10
3.33
29.30
S7
20
11
9
3.38
32.56
S7
20
12
8
3.43
36.63
S7
20
13
7
3.48
41.86
S7
20
15
5
3.53
58.60
S7
20
20
0
3.58
#DIV/0!
S7
20
24
4
7.8
2.15
3.63
73.25
T1
35
-20
55
3.83
1.82
2.10
5.60
T1
35
-19.8
54.8
2.18
5.62
T1
35
-18.8
53.8
2.25
5.72
T1
35
-16.7
51.7
2.32
5.96
T1
35
-15
50
2.39
6.16
T1
35
-13.7
48.7
2.39
6.32
T1
35
-11.8
46.8
2.39
6.58
7
6.1
7.5
4.54
2.18
2.91
2.32
1.9
Page | 77
T1
35
-10
45
2.39
6.84
T1
35
-9.8
44.8
2.39
6.88
T1
35
-9.5
44.5
2.40
6.92
T1
35
-8.5
43.5
2.40
7.08
T1
35
-7
42
2.40
7.33
T1
35
-5
40
2.47
7.70
T1
35
-3
38
2.63
8.11
T1
35
-2
37
2.70
8.32
T1
35
0
35
2.83
8.80
T1
35
2
33
2.96
9.33
T1
35
3
32
3.28
9.63
T1
35
5
30
3.92
10.27
T1
35
7
28
4.24
11.00
T1
35
9
26
4.41
11.85
T1
35
10
25
4.58
12.32
T1
35
11
24
4.72
12.83
T1
35
12
23
4.86
13.39
T1
35
13
22
5.05
14.00
T1
35
15
20
10.6
2.02
5.25
15.40
T1
35
20
15
11.99
2.01
5.97
20.53
T2
35
-20
55
5.48
2.97
1.85
5.60
T2
35
-19.8
54.8
1.94
5.62
T2
35
-18.8
53.8
2.03
5.72
T2
35
-16.7
51.7
2.13
5.96
T2
35
-15
50
2.22
6.16
T2
35
-13.7
48.7
2.24
6.32
T2
35
-11.8
46.8
2.25
6.58
T2
35
-10
45
2.27
6.84
T2
35
-9.8
44.8
2.30
6.88
T2
35
-9.5
44.5
2.32
6.92
T2
35
-8.5
43.5
2.34
7.08
T2
35
-7
42
2.35
7.33
T2
35
-5
40
2.50
7.70
T2
35
-3
38
2.80
8.11
T2
35
-2
37
2.96
8.32
T2
35
0
35
3.08
8.80
T2
35
2
33
3.20
9.33
T2
35
3
32
3.56
9.63
T2
35
5
30
4.28
10.27
T2
35
7
28
4.63
11.00
T2
35
9
26
4.79
11.85
T2
35
10
25
4.94
12.32
5.3
6.11
6.75
8.78
9.29
9.81
6.86
8
9.9
10.55
14.97
15.87
2.21
2.26
2.28
2.07
2.03
2.02
3.09
3.4
3.35
3.3
3.23
3.21
Page | 78
T2
35
11
24
5.24
12.83
T2
35
12
23
5.54
13.39
T2
35
13
22
5.54
14.00
T2
35
15
20
17.7
3.19
5.55
15.40
T2
35
20
15
20.01
3.17
6.31
20.53
T3
35
-20
55
T3
35
-19.8
54.8
6.18
3.5
1.77
5.60
1.86
5.62
T3
35
-18.8
53.8
1.96
5.72
T3
35
-16.7
51.7
2.06
5.96
T3
35
-15
50
2.15
6.16
T3
35
-13.7
48.7
2.17
6.32
T3
35
-11.8
46.8
2.19
6.58
T3
35
-10
45
2.20
6.84
T3
35
-9.8
44.8
2.24
6.88
T3
35
-9.5
44.5
2.25
6.92
T3
35
-8.5
43.5
2.27
7.08
T3
35
-7
42
2.29
7.33
T3
35
-5
40
2.39
7.70
T3
35
-3
38
2.60
8.11
T3
35
-2
37
2.71
8.32
T3
35
0
35
2.80
8.80
T3
35
2
33
2.90
9.33
T3
35
3
32
3.26
9.63
T3
35
5
30
3.98
10.27
T3
35
7
28
4.34
11.00
T3
35
9
26
4.44
11.85
T3
35
10
25
4.55
12.32
T3
35
11
24
4.68
12.83
T3
35
12
23
4.80
13.39
T3
35
13
22
T3
35
15
T3
35
WB1
16.62
7.94
9.37
10.93
11.56
17.08
17.93
3
3.69
4.1
4.04
3.98
3.94
3.94
18.96
3.95
4.92
14.00
20
20.09
3.98
5.05
15.40
20
15
21.87
3.75
5.83
20.53
20
-15
35
2.5
2.5
1.00
8.37
WB1
20
-13.7
33.7
1.04
8.69
WB1
20
-11.8
31.8
1.07
9.21
WB1
20
-10
30
1.11
9.77
WB1
20
-9.8
29.8
1.18
9.83
WB1
20
-9.5
29.5
1.21
9.93
WB1
20
-8.5
28.5
1.25
10.28
WB1
20
-7
27
1.28
10.85
WB1
20
-5
25
1.30
11.72
WB1
20
-3
23
1.33
12.74
3.2
2.5
Page | 79
WB1
20
-2
22
1.36
13.32
WB1
20
0
20
1.39
14.65
WB1
20
2
18
1.40
16.28
WB1
20
3
17
1.52
17.24
WB1
20
5
15
1.76
19.53
WB1
20
7
13
1.88
22.54
3.5
4.7
2.5
2.5
Appendix G – Heat Pump Sensitivity Data
Table 22. Overall heat pump sensitivity
Start Source
Temperature
(°C)
End Source
Temperature
(°C)
ΔT (°C)
ΔCOP
ΔCOP/ΔT
D1
-19.8
15
34.8
3.26
4.39
1.13
0.032
D2
-19.8
15
34.8
3.74
4.95
1.21
0.035
D3
-19.8
15
34.8
3.25
4.95
1.7
0.049
D4
-19.8
15
34.8
4.1
4.97
0.87
0.025
D5
-19.8
15
34.8
3.33
4.8
1.47
0.042
D6
-19.8
15
34.8
3.34
4.68
1.34
0.039
D7
-19.8
15
34.8
3.83
4.61
0.78
0.022
K1
-3
7
10
3.09
4.06
0.97
0.097
K2
-3
7
10
2.93
4.22
1.29
0.129
K3
-3
7
10
2.81
3.92
1.11
0.111
K4
-3
7
10
2.88
3.98
1.1
0.11
K5
-3
7
10
2.85
4.06
1.21
0.121
S1
-15
24
39
2.1
3.67
1.57
0.04
S2
-15
24
39
1.78
3.39
1.61
0.041
S3
-15
24
39
2.21
4.03
1.82
0.047
S4
-15
24
39
2.15
3.32
1.17
0.03
S5
-15
24
39
2.05
4.06
2.01
0.052
S6
-15
24
39
1.81
3.67
1.86
0.048
S7
-15
24
39
1.75
3.63
1.88
0.048
T1
-20
20
40
2.1
5.97
3.87
0.097
T2
-20
20
40
1.85
6.31
4.46
0.112
T3
-20
20
40
1.77
5.83
4.06
0.102
WB1
-15
7
22
1
1.88
0.88
0.04
ID Tag
Start
COP
End
COP
Page | 80
Table 23. Heat pump sensitivity per temperature range
Start Source
Temperature
(°C)
End Source
Temperature
(°C)
ΔTs (°C)
D1
-20
-5
14.8
D2
-20
-5
D3
-20
D4
-20
D5
End
COP
ΔCOP
ΔCOP/ΔTs
3.26
3.59
0.33
0.02
Low
14.8
3.74
4.09
0.35
0.02
Low
-5
14.8
3.25
3.48
0.23
0.02
Low
-5
14.8
4.1
3.96
-0.14
-0
Low
-20
-5
14.8
3.33
3.5
0.17
0.01
Low
D6
-20
-5
14.8
3.34
3.5
0.16
0.01
Low
D7
-20
-5
14.8
3.83
3.7
-0.13
-0
Low
S1
-15
-5
10
2.1
3.02
0.92
0.09
Low
S2
-15
-5
10
1.78
2.86
1.08
0.11
Low
S3
-15
-5
10
2.21
2.96
0.75
0.08
Low
S4
-15
-5
10
2.15
2.94
0.79
0.08
Low
S5
-15
-5
10
2.05
2.93
0.88
0.09
Low
S6
-15
-5
10
1.81
2.61
0.8
0.08
Low
S7
-15
-5
10
1.75
2.59
0.84
0.08
Low
T1
-20
-5
15
2.1
2.47
0.37
0.02
Low
T2
-20
-5
15
1.85
2.5
0.65
0.04
Low
T3
-20
-5
15
1.77
2.39
0.62
0.04
Low
WB1
-15
-5
10
1
1.3
0.3
0.03
Low
D1
-3
7
10
3.66
4.03
0.37
0.04
Medium
D2
-3
7
10
4.16
4.59
0.43
0.04
Medium
D3
-3
7
10
3.56
4.09
0.53
0.05
Medium
D4
-3
7
10
3.99
4.43
0.44
0.04
Medium
D5
-3
7
10
3.58
4.06
0.48
0.05
Medium
D6
-3
7
10
3.54
4.01
0.47
0.05
Medium
D7
-3
7
10
3.75
4.13
0.38
0.04
Medium
K1
-3
7
10
3.09
4.06
0.97
0.1
Medium
K2
-3
7
10
2.93
4.22
1.29
0.13
Medium
K3
-3
7
10
2.81
3.92
1.11
0.11
Medium
K4
-3
7
10
2.88
3.98
1.1
0.11
Medium
K5
-3
7
10
2.85
4.06
1.21
0.12
Medium
S1
-3
7
10
3.08
3.63
0.55
0.06
Medium
S2
-3
7
10
2.92
3.45
0.53
0.05
Medium
S3
-3
7
10
3.04
3.67
0.63
0.06
Medium
S4
-3
7
10
3.02
3.62
0.6
0.06
Medium
S5
-3
7
10
3.01
3.62
0.61
0.06
Medium
S6
-3
7
10
2.67
3.21
0.54
0.05
Medium
S7
-3
7
10
2.66
3.23
0.57
0.06
Medium
T1
-3
7
10
2.63
4.24
1.61
0.16
Medium
ID Tag
Start COP
Temperature
Range
Page | 81
T2
-3
7
10
2.8
4.63
1.83
0.18
Medium
T3
-3
7
10
2.6
4.34
1.74
0.17
Medium
WB1
-3
7
10
1
1.88
0.88
0.09
Medium
D1
9
15
6
4.11
4.39
0.28
0.05
High
D2
9
15
6
4.68
4.95
0.27
0.05
High
D3
9
15
6
4.22
4.95
0.73
0.12
High
D4
9
15
6
4.55
4.97
0.42
0.07
High
D5
9
15
6
4.2
4.8
0.6
0.1
High
D6
9
15
6
4.15
4.68
0.53
0.09
High
D7
9
15
6
4.21
4.61
0.4
0.07
High
S1
9
24
15
3.63
3.67
0.04
0
High
S2
9
24
15
3.44
3.39
-0.05
-0
High
S3
9
24
15
3.71
4.03
0.32
0.02
High
S4
9
24
15
3.58
3.32
-0.26
-0
High
S5
9
24
15
3.67
4.06
0.39
0.03
High
S6
9
24
15
3.27
3.67
0.4
0.03
High
S7
9
24
15
3.28
3.63
0.35
0.02
High
T1
9
20
11
4.41
5.97
1.56
0.14
High
T2
9
20
11
4.79
6.31
1.52
0.14
High
T3
9
20
11
4.44
5.83
1.39
0.13
High
Appendix H – Sample Heat Pump COP Calculations
Using Indoor Air to Alter Source Temperature
𝑇𝑠𝑜𝑢𝑟𝑐𝑒 =
(𝑇𝑂 × (𝑄𝐸 − 𝑄𝐵 ) + 𝑇𝐼 × 𝑄𝐵 )
𝑄𝐸
𝑇𝑠𝑜𝑢𝑟𝑐𝑒 =
2 × (1.68 − 0.16) + 20 × 0.16)
1.68
𝑇𝑠𝑜𝑢𝑟𝑐𝑒 =
3.04 + 3.2
1.68
𝑇𝑠𝑜𝑢𝑟𝑐𝑒 =
6.24
1.68
𝑇𝑠𝑜𝑢𝑟𝑐𝑒 = 3.71
Page | 82
𝐶𝑂𝑃 = 0.0022𝑇𝑠𝑜𝑢𝑟𝑐𝑒 2 + 0.1201𝑇𝑠𝑜𝑢𝑟𝑐𝑒 + 3.3424
𝐶𝑂𝑃 = 0.0022(3.71)2 + 0.1201(3.71) + 3.3424
𝐶𝑂𝑃 = 0.03028102 + 0.445571 + 3.3424
𝐶𝑂𝑃 = 3.82
Using Indoor Air with Heat Recovery to Alter Source Temperature
𝑇𝑠𝑜𝑢𝑟𝑐𝑒 =
(𝑇𝑂 × (𝑄𝐸 − 𝑄𝐵 ) + ((𝑇𝐼 − 𝑇𝑂 ) × 𝐻𝑅𝐸𝑓𝑓 + 𝑇𝑂 ) × 𝑄𝐵 )
𝑄𝐸
𝑇𝑠𝑜𝑢𝑟𝑐𝑒 =
2 × (1.68 − 0.16) + ((20 − 2) × 0.83 + 2) × 0.16
1.68
𝑇𝑠𝑜𝑢𝑟𝑐𝑒 =
3.04 + 2.7104
1.68
𝑇𝑠𝑜𝑢𝑟𝑐𝑒 =
5.7504
1.68
𝑇𝑠𝑜𝑢𝑟𝑐𝑒 = 3.42
𝐶𝑂𝑃 = 0.0022𝑇𝑠𝑜𝑢𝑟𝑐𝑒 2 + 0.1201𝑇𝑠𝑜𝑢𝑟𝑐𝑒 + 3.3424
𝐶𝑂𝑃 = 0.0022(3.42)2 + 0.1201(3.42) + 3.3424
𝐶𝑂𝑃 = 0.02573208 + 0.410742 + 3.3424
𝐶𝑂𝑃 = 3.78
Page | 83
Using Indoor Air with Waste Heat from Compressor to Alter Source Temperature
𝑇𝑠𝑜𝑢𝑟𝑐𝑒 =
(𝑇𝑂 × (𝑄𝐸 − 𝑄𝐵 ) + 𝑇𝐼 × 𝑄𝐵 )
𝐸𝐶
+
𝑄𝐸
(𝑄𝐸 × 𝜌𝐴𝑖𝑟 × 𝐶𝐴𝑖𝑟 )
𝑇𝑠𝑜𝑢𝑟𝑐𝑒 =
(2 × (1.68 − 0.16) + 20 × 0.16)
590
+
(1.68 × 1.2 × 1000)
1.68
𝑇𝑠𝑜𝑢𝑟𝑐𝑒 = 3.71 +
590
2016
𝑇𝑠𝑜𝑢𝑟𝑐𝑒 = 3.714285714 + 0.29265873
𝑇𝑠𝑜𝑢𝑟𝑐𝑒 = 4.01
𝐶𝑂𝑃 = 0.0022𝑇𝑠𝑜𝑢𝑟𝑐𝑒 2 + 0.1201𝑇𝑠𝑜𝑢𝑟𝑐𝑒 + 3.3424
𝐶𝑂𝑃 = 0.0022(4.01)2 + 0.1201(4.01) + 3.3424
𝐶𝑂𝑃 = 0.03537622 + 0.481601 + 3.3424
𝐶𝑂𝑃 = 3.86
Using Indoor Air with Heat Recovery and Waste Heat from Compressor to Alter
Source Temperature
𝑇𝑠𝑜𝑢𝑟𝑐𝑒 =
(𝑇𝑂 × (𝑄𝐸 − 𝑄𝐵 ) + ((𝑇𝐼 − 𝑇𝑂 ) × 𝐻𝑅𝐸𝑓𝑓 + 𝑇𝑂 ) × 𝑄𝐵 )
𝑄𝐸
+
𝑇𝑠𝑜𝑢𝑟𝑐𝑒 =
𝐸𝐶
(𝑄𝐸 × 𝜌𝐴𝑖𝑟 × 𝐶𝐴𝑖𝑟 )
(2 × (1.68 − 0.16) + ((20 − 2) × 0.83 + 2) × 0.16)
1.68
590
+
(1.68 × 1.2 × 1000)
𝑇𝑠𝑜𝑢𝑟𝑐𝑒 = 3.422857143 + 0.29265873
𝑇𝑠𝑜𝑢𝑟𝑐𝑒 = 3.72
Page | 84
𝐶𝑂𝑃 = 0.0022𝑇𝑠𝑜𝑢𝑟𝑐𝑒 2 + 0.1201𝑇𝑠𝑜𝑢𝑟𝑐𝑒 + 3.3424
𝐶𝑂𝑃 = 0.0022(3.72)2 + 0.1201(3.72) + 3.3424
𝐶𝑂𝑃 = 0.03044448 + 0.446772 + 3.3424
𝐶𝑂𝑃 = 3.82
Page | 85
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