Industrial refrigeration equipment

Industrial
refrigeration
equipment
A guide to equipment eligible for
Enhanced Capital Allowances
Industrial refrigeration equipment
2
Contents
Introduction03
Background03
Setting the scene
03
Benefits of purchasing ETL listed products 04
Industrial refrigeration equipment
eligible under the ECA scheme
04
Absorption coolers
05
Air-cooled condensing units
05
Automatic leak detection
06
Automatic air purgers
07
Refrigeration system controls
07
Evaporative condensers
07
Packaged chillers
09
Refrigeration compressors
10
Further information
11
Industrial refrigeration equipment
3
Introduction
Setting the scene
Enhanced Capital Allowances (ECAs) are a straightforward
way for a business to improve its cash flow through
accelerated tax relief. The scheme encourages businesses
to invest in energy saving plant or machinery specified in
the Energy Technology List (ETL) to help reduce carbon
emissions which contribute to climate change.
There are two primary applications of industrial
refrigeration equipment:
The ETL is a register of products that may be eligible for
100% tax relief under the ECA scheme for energy saving
technologies1. The Carbon Trust manages the list and
promotes the ECA scheme on behalf of Government.
This leaflet gives an overview of industrial refrigeration
equipment specified on the ETL and illustrates the
reductions in energy bills that can be realised by investing
in qualifying ETL energy saving equipment over nonqualifying equipment.
Background
• Cooling, freezing and temperature maintenance
during storage, transportation and distribution
of food products.
• Air conditioning systems.
Other applications of industrial refrigeration can be
found in chemical plant (for example, for the separation
of gases), in manufacturing and construction, in ice and
snow sports and in environmental test chambers.
Industrial refrigeration systems use large amounts of
energy and typically cost 7-10 times as much to run
over their lifetime as they do to buy2. The use of energy
efficient industrial refrigeration equipment, such as that
listed on the ETL, can result in significant energy savings
and, therefore, reduced energy bills.
The ETL comprises two lists: the Energy Technology
Criteria List (ETCL) and the Energy Technology Product
List (ETPL). The ETCL defines the performance criteria
that equipment must meet to qualify for ECA scheme
support; whereas the ETPL is the list of products that
have been assessed as being compliant with
ETCL criteria.
Further information
http://www.carbontrust.com/resources/reports/
advice/technology-and-energy-managementpublications or download the Carbon Trust’s
Refrigeration systems technology guide (CTG046) .
1
Eligibility
2
for ECAs is based on a number of factors. Visit http://etl.decc.gov.uk/etl to find out more.
Food and Drink Industry Refrigeration Initiative, Guide 2, Purchase of efficient refrigeration plant, IOR, July 2007.
Industrial refrigeration equipment
4
Benefits of purchasing
ETL listed products
Industrial refrigeration equipment
eligible under the ECA scheme
A system using an ETL listed industrial refrigeration
product can use significantly less energy than a typical
system using non-ETL products. ETL listed products have
a number of energy efficiency advantages, including:
The following sections describe the refrigeration
equipment specified as energy saving under the ECA
scheme. The diagram below illustrates these ECA-eligible
components and their relationship to each other.
• higher efficiencies of specific components
such as compressors;
• better combinations of components in packaged chillers
and condensing units;
• the use of free cooling;
• improved controls; and
Figure 1 Industrial refrigeration equipment eligible
under the ECA scheme
Condensers
Evaporative
condensers
Automatic
air purge
Compressors
• better operation achieved through the use of refrigerant
leak detection and automated air purgers.
Refrigeration
compressors
When replacing equipment, businesses are often
tempted to opt for that with the lowest capital cost;
however, such immediate cost savings can prove to be
a false economy. Considering the life cycle cost before
investing in equipment can help reduce costs and
improve cash flow in the longer term.
Absorption
chillers
The ECA scheme provides businesses with 100% first
year tax relief on their qualifying capital expenditure.
This means that businesses can write off the whole
cost of the equipment against taxable profits in the year
of purchase. This can provide a cash flow boost and an
incentive to invest in energy saving equipment which
normally carries a price premium when compared to less
efficient alternatives.
This leaflet also illustrates the reductions in energy
consumption, carbon emissions and energy bills that can
be realised by investing in qualifying ETL energy saving
equipment over non-qualifying equipment.
Evaporators
System
controls
Refrigerant
leak
detection
Using the baseline scenario below, where appropriate
the potential financial (£), energy (kWh) and carbon
savings (tonnes CO2) have been calculated for replacing
component parts of a refrigeration system with ETL
qualifying equipment to highlight the potential benefits
that can be achieved.
Baseline scenario:
• Refrigeration plant with an installed cooling capacity
of 400kW.
• Producing chilled water at 5ºC.
Important
Businesses purchasing equipment must check
the ETPL at the time of purchase in order to verify
that the named product they intend to purchase is
designated as energy saving equipment. Industrial
refrigeration equipment that meets the ETL
eligibility criteria but is not listed on the Energy
Technology Product List (ETPL) at the time of
purchase is not eligible for an ECA.
• Compressor power demand of 100kW.
• Annual operating hours: 8,000.
• Electricity price 9p/kWh.
• Electricity CO2 emission factor: 0.524kg CO2/kWh.
• Annual savings do not degrade.
Industrial refrigeration equipment
5
Absorption coolers
Absorption coolers (chillers) are heat-driven (as opposed to
electrically driven) machines used in industrial refrigeration
to cool a process or product. They operate using an
absorption refrigeration cycle. In this cycle, two fluids are
used – a refrigerant in conjunction with an ‘absorber’ –
which have a high mutual solubility. Most commercially
available absorption chillers use either Ammonia and
water, or water and Lithium Bromide. Figure 2 shows
the absorption refrigeration cycle. The compressor of
the conventional system is replaced by an absorber and
generator. The refrigerant vapour from the evaporator
is absorbed at low pressure and low temperature. The
resulting solution is then pumped to high pressure and
heated in the generator where the refrigerant is released.
The remainder of the cycle is conventional.
Figure 2 Absorption refrigeration cycle
Equivalent to the compressor in
a vapour compression system
Condenser
Generator
Expansion
valve
Strong
solution
Weak
solution
Heat exchanger
Solution
pump
Pressure
reducing
device
By installing an ETL listed absorption chiller in
place of a baseline scenario refrigeration system
(400kW chiller), the potential annual savings are
calculated as:
• £72,000.
• 800,000kWh.
• 419 tonnes CO2.
In this scenario the absorption cooler is using
waste heat from a CHP plant. The heat is assumed
to be free.
Air-cooled condensing units
An air-cooled condensing unit consists of a compressor
and an air-cooled condenser combined with various
ancillary components, such as a liquid receiver, shut
off valves, filter drier, sight glass and controls. The unit
is factory assembled and wired as a complete unit. It
provides a convenient method for ‘powering’ a cold room
or other cooling equipment that has an evaporator with
expansion valve control. Refrigerant vapour from the
evaporator is compressed and condensed for return to
the evaporator as a high pressure liquid. This process is
shown in Figure 3, below.
Figure 3 Simple refrigeration circuit showing
condensing unit linked by two pipes to a typical
cooling load
Condensing
unit
Condenser
Compressor
Evaporator
Absorber
Absorption chillers may be driven by waste heat from
thermal processes and, in particular, from combined heat
and power (CHP) systems. This offers significant benefits to
CHP schemes since this use of the additional heat load may
allow CHP plant to be larger and have increased running
hours. In addition the electrical demand of the site will also
be reduced.
3
CHP Quality Assurance (CHPQA) Programme (http://chpqa.decc.gov.uk)
Heat out
Expansion
Valve
Heat in
Evaporator
Cold
room
Industrial refrigeration equipment
Medium and low temperature condensing units
are widely used for frozen and chilled food storage.
Evaporating temperatures are typically -35ºC for frozen
product and -10ºC for chilled product. High temperature
units are used in air conditioning applications. Figure 4
shows a typical air-cooled condensing unit.
6
By installing an ETL listed air-cooled condensing
unit in place of one that is 25% less efficient, the
potential annual savings are calculated as:
• £1017.
• 11,300kWh.
• 5.9 tonnes CO2.
Figure 4 Condensing unit showing compressor
compartment
Based on the following scenario:
–– 11kW continuous load at -20ºC with the
condensing unit running approximately 20h/day.
–– Refrigerant R404A.
–– No condensing pressure control i.e. pressure
allowed to fall at low ambient conditions.
Automatic leak detection
Automated permanent refrigerant leak detection systems
are products designed to continuously monitor the
atmosphere in the vicinity of refrigeration equipment and,
in the event of detection of refrigerant, raise an alarm.
The early warning of refrigerant leaks allows repairs to be
carried out early. This improves the energy efficiency of
the refrigeration system and reduces carbon emissions
and other greenhouse gases.
Image courtesy of Hubbard Products Ltd
The energy efficiency of an air-cooled condensing unit is
dependent on refrigerant and operating conditions and is
expressed as a Coefficient of Performance (COP)4. The
rating conditions for condensing units are set out in EN
132155. The threshold eligibility values for COP for low,
medium and high temperature applications are specified
in the ECA criteria. In order to be eligible for an ECA, the
unit must be rated at one or more of these conditions.
Efficiency can be enhanced by liquid sub-cooling within
the unit. This can be achieved by using either additional
dedicated coils in the condenser or two-stage or
economised cycles. In order to be eligible for an ECA,
the additional sub-cooling method and liquid temperature
must be stated.
4
Defined
The majority of industrial refrigeration systems currently
use either an HCFC or HFC refrigerant. Systems detecting
these and other refrigerants, such as Carbon Dioxide,
are covered by the ETL. However, Ammonia detection
devices are currently outside the scope of the ETL.
Refrigerant leakage may lead to a reduction in the
efficiency of refrigeration equipment by causing a
direct reduction in COP. Leaking systems can therefore
contribute twice to climate change; once through the
direct emission of refrigerant, and secondly through
increased emissions from higher electricity consumption.
A recent estimate suggested that average refrigerant
leakage rates are around 20% of total charge per year,
and that typically a leaking system experiences an 11%
reduction in COP6.
Automatic permanent leak detection systems are usually
multi-point or single point sensing devices. A single point
detector is a self-contained device installed in a plant
room in a location where it is likely to detect the early
onset of leakage. Multi-point detectors are often aspirated
(they draw or suck air down tubes from each sample
point to a central detector unit and control panel) and
can typically monitor up to 16 locations.
as the ratio of cooling capacity to electrical power input, (including both compressor condenser fan power).
Standard EN13215 Condensing units for refrigeration – Rating conditions – tolerances and presentation of manufacturer’s performance data, 2000.
6
Gartshore J. Energy Efficiency and Leakage Reduction. Refrigeration: Optimising refrigeration systems for building services engineers. CIBSE 2008.
5
European
Industrial refrigeration equipment
Automatic leak detection systems eligible for ECAs must
be able to continuously and permanently monitor the
refrigeration system for refrigerant leakage by detecting
the presence of one or more specified refrigerants.
They must also raise an audible alarm when the level of
refrigerant in the atmosphere exceeds a specified level.
By installing an ETL listed automatic leak
detection system in a plant room with a chiller,
based on the baseline scenario provided, and
assuming an 11% reduction in COP due to
undetected refrigerant leakage, the potential
annual savings are calculated as:
• £8,899.
• 98,876kWh.
• 51.8 tonnes CO2.
Automatic air purgers
Automatic air purgers continuously purge non-condensable
gases (such as air) from the condenser and receiver of a
refrigeration system in order to reduce condenser pressure
(also known as head pressure). This reduces compressor
power use and increases the cooling capacity of the plant.
The presence of non-condensable gases increases
head pressure in two ways: the partial pressure of the
non-condensable gas adds to the partial pressure of the
refrigerant gas to increase the total head pressure, and
the non-condensable gases reduce the heat transfer rate
in the condenser. These non-condensable gases may
become introduced during maintenance and can leak into
the system, or they may result from the breakdown of
refrigerants and oils.
7
Refrigeration system controls
Refrigeration system controllers vary enormously
in function and complexity. The simplest control is a
thermostat which simply controls the temperature of the
cooled space. More complex refrigeration systems, such
as those with multiple compressors, ideally require more
sophisticated control. When used in the right way, these
controls can significantly reduce the amount of energy a
refrigeration system uses.
The ETL currently includes:
• System management units or packages consisting of
one or more control units or modules that are designed
to optimise an entire refrigeration system, including the
operation of refrigeration compressors, evaporators and
condensers.
• ‘Add-on’ controllers that are designed to be used in
conjunction with a specific system management unit
or package, and enable the operation of additional
refrigeration compressors, evaporators and condensers
to be optimised.
Using the baseline scenario below, the potential financial
(£), energy (kWh) and Carbon savings (tonnes CO2) have
been calculated for the use of an ETL listed refrigeration
system controllers.
The potential annual savings achieved as a result
of the installation of ETL listed refrigeration system
controls at an industrial site running 25 evaporators
and three cold rooms are calculated as:
• £3,702.
• 41,133kWh.
• 21.6 tonnes CO2.
Automatic air purgers are generally suited to larger
refrigeration plant, where the build up of non-condensable
gases is a recurring problem.
The potential annual savings achieved as a result
of the installation of an automatic air purger in a
cold store plant consuming 70kW on average are
calculated as:
• £7,884.
• 87,600kWh.
• 45.9 tonnes CO2.
4
COP is the ratio of refrigerating capacity to electrical power absorbed and is defined in EN13215:2000.
Standard EN13215 Condensing units for refrigeration – Rating conditions – tolerances and presentation of manufacturer’s performance data,
2000.
Gartshore J. Energy Efficiency and Leakage Reduction. Refrigeration: Optimising refrigeration systems for building services engineers. CIBSE 2008.
5
European
6
Industrial refrigeration equipment
8
Evaporative condensers
Condensers are used in a refrigeration system to
liquefy the refrigerant gas discharged by the compressor.
Most condensers used are air-cooled, i.e. ambient air is
used to remove the heat from the condensing refrigerant.
In an evaporative condenser, the gas to be condensed
flows through a coil which is continually wetted on the
outside by recirculated water. Air is drawn over the coil,
evaporating some of the water. This improves the
rate at which heat is rejected from the refrigerant gas,
allowing it to condense at a lower temperature relative
to the air temperature.
Figure 5 Diagram showing typical evaporative
condenser operation
2
An evaporative condenser has two advantages over an
air-cooled type:
• The evaporation of water is more effective at removing
heat than dry air.
• The heat is rejected against the wet bulb ambient
temperature rather than the dry bulb. The wet bulb
temperature is up to 8ºC lower than the dry bulb in
hot weather.
The result is Evaporative condensers allow refrigeration
systems to operate with lower head pressures and
higher efficiencies than can be achieved using air-cooled
condensers or water-cooled condensers. Evaporative
condensers must be kept clean and the fans and
water pumps must be operational to ensure optimum
performance. In addition, the water must be treated to
prevent legionella formation.
9
6
1. Air in
2. Air out
3. Vapour in
4. Liquid out
5. Cold water basin
6. Water distribution system
7. Coil
8. Spray water pump
9. Eliminators
10. Optional extended surface.
3
10
7
7
4
1
8
55
By installing an ETL listed evaporative condenser in place of an air-cooled condenser on a system with
500kW heat rejection, the potential annual savings are calculated as:
• £7,368.
• 81,866kWh.
• 42.9 tonnes CO2.
Assuming that the minimum condensing temperature in both systems is 20ºC, fan and pump power are the
same and the cost of water treatment for the evaporative condenser is not included.
Industrial refrigeration equipment
9
Packaged chillers
The ECA Scheme covers four categories of products:
Packaged chillers are factory assembled refrigeration units
that are designed to cool liquid using a self contained,
electrically-driven mechanical vapour compression system.
A packaged chiller includes the refrigeration compressor(s),
controls and the evaporator in the packaged unit. The
condenser may be built-in or remote. Some packaged
chillers may also include a hydronic unit comprising a chilled
water buffer tank and a chilled water circulation pump.
1. Air-cooled packaged chillers that provide cooling only.
2.Air-cooled, reverse cycle, packaged chillers that
provide both heating and cooling.
3.Water-cooled packaged chillers that provide
cooling only.
4.Water-cooled, reverse cycle, packaged chillers that
provide both heating and cooling.
Figure 6 Air-cooled packaged chillers
Condenser
fans
Condenser
Condenser fans
fans
Control
Control
Control
panel
panel
panel
Finned
coil
Finned
coil
Finned
coil
condenser
condenser
condenser
Chilled
Chilled
Chilled
water
water
water
pump
pump
pump
Chilled
water
Chilled
water
Chilled
water
inlet
&
outlet
inlet
&
inlet & outlet
outlet
Compressor
Compressor
Compressor
By installing an ETL listed 500kW air cooled
packaged chiller the potential annual savings are
calculated as:
• £1,964.
Evaporator
Evaporator
Evaporator
• 21,825kWh.
• 11.4 tonnes CO2.
Based on the following scenario:
Figure 7 Water-cooled packaged chillers
• Installation of one 500kW capacity air cooled
packaged chiller with an average EER of 2.8
Water
connections
to
dry
Water
connections
to
dry
Water
connections
to
dry
air
cooler
or
cooling
tower
air
cooler
or
cooling
tower
air cooler or cooling tower
Condenser
Condenser
Condenser
Chilled
Chilled
Chilled
water
water
water
pump
pump
pump
Chilled water
water
Chilled
Chilled
inlet &
& water
outlet
inlet
inlet & outlet
outlet
Control
Control
Control
panel
panel
panel
Compressor
Compressor
Compressor
Evaporator
Evaporator
Evaporator
Refigerant
connections
to
Refigerant
connections
to
Refigerant
connections
to or
remote
air
cooled
condenser
remote
air
cooled
condenser
remote
air cooled
condenser or
or
evaporative
condensers
evaporative
condensers
evaporative condensers
Control
Control
Control
panel
panel
panel
Chilled
water
Chilled
water
Chilled
water
inlet
&
outlet
inlet
&
inlet & outlet
outlet
Compressor
Compressor
Compressor
Evaporator
Evaporator
Evaporator
• The chiller serves an air conditioning load and
operates for 500 hours per year.
Note that an EER of 2.25 is the minimum EER
value for compliance with the current Building
Regulations ADL guidance and also corresponds
to Eurovent class F.
Figure 8 Packaged chillers with remote
air-cooled condensers
Chilled
Chilled
Chilled
water
water
water
pump
pump
pump
• Replacement of a 500kW air cooled packaged
chiller which has an average EER of 2.25.
Industrial refrigeration equipment
Refrigeration compressors
The compressor in a refrigeration system compresses the
refrigerant gas from the low pressure of the evaporator
to a higher pressure so that it can condense in the
condenser, thus rejecting heat to ambient air or water.
The ECA Scheme covers the following 6 types of
refrigeration compressor:
1. High temperature with HFC or HC refrigerant.
2. Medium temperature with HFC or HC refrigerant
3. Low temperature with HFC or HC refrigerant
4. Medium temperature transcritical/subcritical with
R744 refrigerant
5.Low temperature transcritical/subcritical with
R744 refrigerant
6.Low temperature subcritical cascade with
R744 refrigerant
The compressor and motors are housed either in a
hermetic enclosure which is welded tight, or in a semi
hermetic enclosure which has gasketed removable
covers. Both types are eligible for ECAs.
By installing an ETL listed compressor instead
of a 15% less efficient one, the potential annual
savings are calculated as:
• £1,152
• 12,800kWh.
• 6.7 tonnes CO2.
Based on the following scenario:
• 40kW continuous load at +5ºC with the
compressor running approximately 20h/day.
• Refrigerant R404A.
• Condensing temperature 10K above ambient, with
pressure allowed to fall at low ambient conditions
to a minimum condensing condition of 20ºC.
10
Information for purchasers
For further information about the ECA scheme,
the Energy Technology List (ETL) and other
Technology Information Leaflets in the series
please visit www.carbontrust.co.uk/eca, contact
the Carbon Trust on 0800 085 2005 or email
customercentre@carbontrust.co.uk
Industrial refrigeration equipment
11
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