Hybrid Heating Systems Heat Pumps Working with a Traditional Boiler

Hybrid Heating Systems Heat Pumps Working with a Traditional Boiler
Hybrid Heating Systems
Heat Pumps Working with a Traditional Boiler
The name Mitsubishi is
synonymous with excellence
Founded in 1921, Mitsubishi Electric is now a
global, market leading environmental technologies
manufacturer. In the UK, the Living Environmental
Systems Division provides proven solutions that
heat, cool, ventilate and control our buildings in
some of the most energy efficient ways possible.
Increasing energy bills, the need to reduce carbon emissions
and the raft of challenging legislation are driving the demand
for alternative forms of heating to improve energy efficiency.
Mitsubishi Electric has specifically designed the Ecodan range
for UK homes and buildings. Ecodan air source heat pumps
provide renewable energy to challenge traditional heating
methods, whilst meeting the energy and carbon reduction
demands of today and beyond.
We believe that global climate challenges need local solutions.
Our aim is to help individuals and businesses reduce the energy
consumption of their buildings and their running costs.
At Mitsubishi Electric we have evolved and today we offer
advanced environmental systems that really can make a
world of difference.
Our Hybrid Ecodan heating systems
deliver efficient, renewable heating in
tandem with a traditional boiler
The Heating
challenge that
we all face
In March 2012 the DECC (Department for Energy
and Climate Change) published a document entitled
‘The Future of Heating: A strategic framework for
low carbon heat in the UK’. This highlighted the
challenges in the way we use our heat, and also
looked at low carbon alternatives for the future.
In the UK the majority of energy we use is to provide heating
to our buildings. Most of this heat is generated by burning
fossil fuels - 80% alone comes from burning gas and this alone
accounts for 30% of the UK’s greenhouse gas emissions.
Much of the attention is placed on improving the thermal
performance of new build properties, whereas 80% of the
properties we will be living in by 2050 are already built.
This is a major focus area, and these buildings may need
a mixture of solutions to allow them to perform better.
A further report was published a year later in March 2013:
“The Future of Heating: Meeting the challenge” and leads
on from the strategic framework document to look at practical
solutions to delivering carbon reduction in buildings. The
report outlines several transitional steps and technologies to
help get to a truly low carbon, renewable future. One of these
transitional technologies is Hybrid or Bivalent heat pumps.
Ecodan System
The desire to move off-gas grid heating to renewable
technologies like heat pumps is strong, with many
Governmental policies choosing this model as an easy win.
Through mixing traditional technologies and new renewable
heat pumps, many properties on the gas grid would be able
to make a cost-effective change to reduce both carbon
emissions and running costs. This will allow for our dependency
on gas to gradually decrease and provide time to invest in
the national infrastructure required to serve many electrically
driven heating systems.
The report models the uptake in these transitional technologies
to show that in 2030 approximately 26% of the UK’s heating
energy output will be met by air source heat pumps alone,
and as much as 56% will be met by hybrid systems.
A hybrid system allows heat pumps to efficiently
deliver the majority of the energy requirements,
and for a traditional boiler to provide the peak
output when outdoor conditions fall below a point
where heating in this way is more cost effective.
The report also goes on to highlight the steps that are needed
within our energy infrastructure in order to make the change
from traditional fossil fuels to low carbon heating.
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Ecodan Heat Pump Heating Systems
Mitsubishi Electric has developed Ecodan to operate as a hybrid/bivalent system,
allowing users to upgrade their traditional heating system by installing and running
a heat pump alongside it.
Heating UK homes with Ecodan air source heat pumps is now a viable and credible alternative to traditional
methods and can help to combat rising energy bills through greater efficiency.
By using an Ecodan to provide space heating and hot water, it is possible to reduce a home’s CO2 emissions
and running costs. Ecodan uses inverter-driven heat pump technology to harvest and upgrade free, renewable
energy from the outdoor air to deliver heating and hot water, even in temperatures as low as -20°C.
For every 1kW of input electrical energy, Ecodan harvests and upgrades
renewable heat from the outdoor air to provide the home with an average
of at least 3.2kW of heat output.*1
Outstanding benefits:
Achieves level 4 of the Code for Sustainable Homes with no additional measures
and can be even higher when used in conjunction with other improvements
Improves energy use leading to lower running costs and CO2 emissions
5% VAT rating on capital and install costs
Low noise levels - Ecodan has achieved the Noise Abatement Society’s Quiet Mark
MELCloud Wi-Fi control of Ecodan system from anywhere in the world
SD Card commissioning and logging
MCS approved and qualifies for the Renewable Heat Incentive
*1 The overall system efficiency and energy savings will depend on the comparison with your current heating system,
satisfactory system design and installation, and operational settings i.e. how you use the heating system.
Page 5
Hybrid heating
systems deliver
a perfect solution
for the future
By using Ecodan as part of a hybrid system this
means that all the benefits of lower running costs
for the vast majority of the year can be taken
advantage of, and when the outdoor conditions
fall below a point where the heat pump is no longer
the most efficient heat source, the system can
switch over to the traditional boiler.
Bringing together an already existing traditional boiler
and a renewable heat pump means the investment can
be much more flexible, for example; if you already have
a combi-boiler your hot water can remain delivered by
this system while the heat pump can provide space
heating for the majority of the year.
By working in this way the initial investment can be
kept low, whilst still delivering a significant contribution to
run cost savings and taking advantage of Government
incentives such as the Renewable Heat Incentive (RHI).
Enabling consumers to maximise energy efficiency, comfort
levels and reliability, yet still retain their existing heating
system provides total peace of mind.
Typical example of a Hybrid system utilising
Ecodan and an existing combi boiler
Ecodan Hydrobox
Ecodan Heat Pump
Wireless Remote Controller
Turning boiler on /off according
to operational conditions
Other source
(Gas, Oil, etc)
Low Loss Header
Existing Radiators
Instant DHW
Hybrid system example application 1
Page 6
Typical example of a Hybrid system
utilising Ecodan and an existing boiler
and hot water cylinder
Ecodan Heat Pump
Flow Temperature Controller
Wireless Remote Controller
Low Loss Header
Turning boiler on/off according
to operational conditions
Other source
(Gas, Oil, etc)
Existing Boiler
Existing Cylinder
Existing Radiators
Hybrid system example application 2
Controlling your Hybrid heating system
There are various different settings for boiler switchover when using Ecodan as part
of a hybrid system:
Energy price information is stored on the Ecodan’s SD card prior to set up.
Heat Source switchover occurs whenever the Ecodan determines which
heat source has the lowest running costs.
An outdoor temperature switchover point is chosen by the installer, the
outdoor temperature is constantly monitored, and whenever the set outdoor
temperature is reached the boiler will automatically switch on.
CO2 Emissions
Similar to the way in which the Ecodan can switch heat sources based on
cost, it can do the same in respect of CO2 emissions. Once data is input on
to the SD card prior to set up, Ecodan will determine which heat source is
most efficient based on CO2 emissions.
Heat Pump Failure
In the unlikely case of an Ecodan failure, a signal will be sent to
the boiler to switch on as backup.
External Input
Heat source switchover can also be enabled from an external input, such as
a third party thermostat, Building Energy Management System (BEMS) or
potentially a utility provider signal.
Page 7
Typical semi detached houses showing both
Standard and Hybrid Ecodan heating applications
Standard house
In this example Ecodan is being used as the sole
heating and hot water system, fully optimised to
deliver maximum efficiency and comfort.
Up to 6 Ecodan units of the same capacity (up to 84kW)
can be operated as one system.
Intelligent Control
Ecodan’s load and weather compensation
feature will monitor indoor and outdoor
temperatures and adjust the system flow
temperatures to suit.
This makes sure that energy use is kept at a
minimum, whilst ensuring comfort is always at
a maximum for the user.
Page 8
Hybrid house
In this example Ecodan is being used in conjunction with an existing
boiler to maximise efficiency, run costs and CO2 emissions.
Ecodan can switch between heat sources based on various parameters such as; temperature,
cost, CO2 emissions, unit failure and also via an external input if required. This allows the
homeowner to have an individual system set up that is customised as they wish.
Ecodan outdoor units utilise
highly efficient inverter technology
to heat water, reducing running
costs and carbon emissions.
SD Card
Enables commissioning data to be
pre-programmed onto an SD card
and then utilised when an engineer
attends site.
The SD card also holds operation and fault
information, as well as system run data for
easy system interrogation by engineers.
Page 9
Hybrid systems
and the
Heat Incentive
Making the decision to move towards a new
renewable system can sometimes be a daunting
and difficult one - perhaps the building is an older
property, or the capital isn’t available to invest. By
choosing to use a mixture of technologies on site
many of these barriers can be removed.
This decision is made even more attractive by the fact that
the Domestic Renewable Heat Incentive (Domestic RHI) is
also available for hybrid systems. To claim RHI payments, the
hybrid or bivalent systems will require the use of a heat meter,
which Mitsubishi Electric can assist with.
The meter allows the user and Ofgem to know exactly how
much heat is being produced by the renewable system,
with the traditional boiler making up the remaining energy.
This figure is then used to calculate the RHI payment.
By bringing together technologies, a more balanced
investment can be made and the system sized to ensure
that you get the most from your heating, as well as maximising
the financial reward from the available incentives.
When to use Hybrid Heat Pump Systems
Single or Multiple
Heat Pump System
New Build
Thermally efficient building with low heating load Heating and Domestic Hot Water
Thermally efficient building
Cavity walls can be filled and loft insulation installed Heating and Domestic Hot Water
Thermally efficient building, but lower
capital investment
Sometimes the initial capital available means changes are difficult.
Heating by Heat pump / Combi Boiler, Domestic Hot Water by Combi Boiler
(heat meter required)
(heat meter required)
Older building with a large heat load
Perhaps some improvements can be made, but the heating load is
larger than an average property
Older building with a large heat load
and traditionally sized radiators
Some older buildings will not be able to change radiators and therefore
need high water temperatures and low ambient temperatures
Domestic RHI Compliant
Page 10
Hybrid System
(heat meter required)
(heat meter required)
Heating Power Coverage of a Property
Power Coverage (kW)
Heating Energy Coverage of a Property
Energy Coverage (kWh)
Ambient Temperature (ºC)
Ambient Temperature (ºC)
Example 1: On-gas grid 3-bed detached property
Fuel Cost: Electricity Price 13.5p/kWh / Gas Price 4p/kWh
DHW = Domestic Hot Water
Total 7 Year
with RHI
Rate of
Heating and DHW by Gas Combi-Boiler
Heating and DHW by 8.5kW Ecodan Heat Pump 1
Hybrid - Heating by 5kW Ecodan Heat Pump
and DHW/Back Up Heating by Combi-Boiler
In this example the owner of the property has a 10 year old combi-boiler which is requiring an increasing number of maintenance visits for
small problems. The owner is considering buying a new boiler in the summer period to ensure there are no problems during the next winter.
This is a perfect time to invest in a new Ecodan hybrid heat pump - allowing you to run your boiler for only 25% of the year,
therefore extending its life.
Radiators can remain unchanged as the boiler will be used when the ambient temperature drops too low.
The system allows you to take advantage of RHI by metering the output of the renewable Ecodan.
The hybrid control on the Ecodan intelligently turns on/off the boiler to achieve the lowest running cost and highest levels of comfort.
Example 2: Off-gas grid old uninsulated property
Fuel Cost: Electricity Price 13.5p/kWh / Oil Price 5.5p/kWh
DHW = Domestic Hot Water
Total 7 Year
with RHI
Rate of
Heating and DHW by 11.2kW Ecodan Heat Pump 1
Hybrid - Heating by 8.5kW Ecodan Heat Pump
and DHW/Back Up Heating by Combi-Boiler
Heating and DHW by Oil Combi-Boiler
In this example the owners have an older off-gas grid property with a high heat load and that is not very well insulated. They are worried
about their oil bills continually increasing and have been told in the past that a heat pump is unable to deliver a solution to their building.
New hybrid functionality on the Ecodan heat pumps mean this type of building can now use a heat pump.
Radiators can remain unchanged as the oil boiler will be used when the ambient temperature drops too low.
The system allows you to take advantage of RHI by metering the output of the renewable Ecodan.
The hybrid control on the Ecodan intelligently turns on/off the boiler to achieve the lowest running cost and highest levels of comfort.
Page 11
Hybrid Application Case Study
Heat pumps help keep bills down in hybrid installation
The installation of an Ecodan system into a 3-bedroom detached house in Bedfordshire
has demonstrated how effectively the heat pump will work in conjunction with traditional
heating systems to maximise efficiency and reduce both installation costs and emissions.
The 5kW Ecodan and pre-plumbed 180-litre cylinder was
installed in April 2013, and is working as a hybrid heating
system with a gas boiler and a wood burning stove to
provide all the heating and hot water the family needs.
The timber-framed, brick-clad house was built in 2006
and with a young baby in the home the family has a high
hot water demand. “It’s important for us that we have
hot water whenever we want it and to also keep our son’s
bedroom at a pre-set level of 20°C,” explains Alice Knight
the homeowner.
The system has been set up so that the Ecodan wireless
thermostat in the baby’s bedroom becomes the ‘master’
unit during the night ensuring that the temperature is
constant. The hot water is also set to automatically
replenish whenever the cylinder temperature drops below
43°C, which suits the family’s lifestyle as it ensures that
there is always hot water on demand. Despite this hot
water requirement, the system has returned a COP
(Coefficient of Performance) of 3.0.
The family has also programmed the individual prices of
gas and electricity into the Ecodan’s control system, so
that it can decide when it is best to run the heat pump or
the gas boiler to maintain comfort levels in the most cost
efficient way possible. This way, the family knows that the
gas boiler will only come on when it demonstrates that it
is the most economical means of heating the home.
The home has a floor space of 105m2 and is divided into
two ‘electronic’ heating zones with priority switching
between upstairs and downstairs based on which areas
of the house are being occupied during different times of
the day. Due to the hybrid configuration most of the
original radiators could also be retained.
The house has an EPC (Energy Performance Certificate)
rating of ‘C’ for energy efficiency, with heat losses
calculated at 4.3kW at -3°C outdoor temperature
and 21°C indoor. The Knight family is also expecting
to benefit from around £500 a year in payments from
the Renewable Heat Incentive.
“We have been delighted with the heating and especially the constant temperature
it provides,” says Alice. “The system has also quickly adapted to suit our lifestyle
and controls both the heat pump and the gas boiler, so we really don’t need to
worry about anything.”
For real world performance monitoring of different sites around the UK, take a look
at the Ecodan Dashboard: dashboard.mitsubishielectric.co.uk
Page 12
Hybrid Application Case Study
Veteran embraces renewable technologies
with hybrid heating system
A former WW2 veteran has shown the way to a sustainable future with the installation
of a hybrid Ecodan air source heat pump to work alongside his existing gas boiler.
Mr Durward of Newick, Lewes who flew Lancaster bombers, describes himself as a ‘gadget man’ and always willing to
experiment with new ideas, so when he heard about the possibility of reducing the heating bills for himself and his wife
by installing an Ecodan system, he was eager to investigate. “Heat pumps seem to offer a real solution to the problems
associated with fossil fuel heating, which is no longer a sustainable way of keeping our homes warm,” he explained.
With the installation of an 8.5kW Ecodan monobloc air source heat pump and packaged hydrobox, Mr Durward now
has a renewable heating system which also qualifies for the Renewable Heat Incentive (RHI). Designed specifically with
a bivalent function for use in conjunction with conventional boilers, the hydrobox is pre-plumbed and wired for faster
installation and also offers simplified SD card commissioning. With the capability of providing two-zone space heating
via a modern, simplified graphical controller, the system ensures that the Durward’s are able to completely control
their heating.
Mr Durward has always had a fascination for self-sufficiency and has already sunk a borehole down to 200 feet to
supply water to the property. “I put in a solar thermal system over 35 years ago which worked well but I have now
changed this to a Photovoltaic system to generate our own electricity,” he added.
East Sussex-based Payne’s Heating and Plumbing Services, who are an Accredited Ecodan Installer and renewable
specialist, fitted both the heat pump and the PV system. At Mr Durward’s request, they have also incorporated a power
diverter, which transfers any excess electricity generated to the immersion heater, giving the couple regular free tanks
of piping hot water.
The Durward’s had an upgrade to a new high efficiency condensing boiler fitted alongside the hybrid Ecodan
system. However, this has had such little use since the introduction of the heat pump that Mr Durward
received a call from his utility company, which believed there might be a mistake due to the low energy reading.
Designed specifically to integrate Ecodan with a third party cylinder the hydrobox is pre-plumbed and wired for faster
installation and also connects to a wireless remote controller.
“Mr Durward is delighted with the way the system is working and we often use him as a contact for other clients looking
at similar works,” explained Dave Crock of Paynes Heating and Plumbing Services.
Mitsubishi Electric has also arranged for a MELCloud Wi-Fi system to be installed so that the heat pump can be
monitored and Mr Durward can control and alter his system from either his armchair or anywhere else in the world.
Page 13
Making a world
of difference
with Ecodan
Hybrid heating systems using an Ecodan offer a
real opportunity for reductions in running costs
and carbon emissions.
With renewable energy targets and carbon reduction pressure
on our legacy stock coming up to similar levels as our new
buildings, we need to start taking real steps towards finding
a solution. Hybrid heating systems allow property owners to
make a cost effective change and meet the challenges head on.
Installing and running Ecodan systems as part of a hybrid
heating system, can not only deliver carbon emissions
reductions today, but as the electrical grid becomes cleaner
with the advent of solar PV, wind farms and high efficency
power stations, these buildings will continue to deliver
increased emission savings long into the future.
This legacy stock of buildings is not going away,
but with the help of Ecodan technology we have
a real opportunity to deliver highly efficient
renewable heating solutions, whilst providing
hard cash savings through the reduction of
running and maintenance costs.
Mitsubishi Electric are also committed to lowering our
own production emissions levels and those generated by
our equipment during their lifetime. Our Green Gateway
philosophy strives to improve energy efficiency and take
a more responsible approach to energy use, helping the
nation to achieve its climate goals.
Page 14
The Ecodan Hybrid heating system
allows consumers to have the best
of both worlds in one single
heating system
Telephone: 01707 282880
email: [email protected]
web: heating.mitsubishielectric.co.uk
UNITED KINGDOM Mitsubishi Electric Europe Living Environmental Systems Division
Travellers Lane, Hatfield, Hertfordshire, AL10 8XB, England
General Enquiries Telephone: 01707 282880 Fax: 01707 278881
IRELAND Mitsubishi Electric Europe Westgate Business Park, Ballymount, Dublin 24, Ireland
Telephone: Dublin (01) 419 8800 Fax: Dublin (01) 419 8890 International code: (003531)
Country of origin: United Kingdom – Japan – Thailand – Malaysia. ©Mitsubishi Electric Europe 2014. Mitsubishi and Mitsubishi Electric
are trademarks of Mitsubishi Electric Europe B.V. The company reserves the right to make any variation in technical specification to the
equipment described, or to withdraw or replace products without prior notification or public announcement. Mitsubishi Electric is constantly
developing and improving its products. All descriptions, illustrations, drawings and specifications in this publication present only general
particulars and shall not form part of any contract. All goods are supplied subject to the Company’s General Conditions of Sale, a copy of
which is available on request. Third-party product and brand names may be trademarks or registered trademarks of their respective owners.
Printed in August 2014
SAP No.270378
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