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ESP Air Source Heat Pumps Classic Range Delivering Ecovalue

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Air-source heat pumps are similar in operation to ground-source heat pumps, except that heat is extracted from the external air rather than the ground. Air-source heat pumps are classified as either air-to-air or air-to-water depending on whether the heat distribution system in the building uses air or water. The main advantage of air-source heat pumps over ground-source heat pumps is their lower installation cost. A ground-source heat pump requires a network of underground coils that is used to extract heat from the ground. By comparison, air-source heat pumps extract the heat directly from the outside air and so avoid these potential problems. Other benefits of air-source heat pumps over conventional boilers include no combustion or explosive gases within the building, no need for flues or ventilation, no local pollution, long life expectancy with minimal/no annual maintenance, simple engineering/fitting and much lower costs of running. Stylishly designed domestic units can also be widely used in commercial buildings. With the pump, plate heat exchanger, water storage and flow switch fitted inside as standard, the units are smaller than many on the market. The units are relatively light, making transportation to and around the installation site much easier. This, in turn, makes installation easier. Smart controller LCD, LED or Carol Controllers are for option.

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SPECIFICATION

Model

ESP(A)410

020B

030B

040B

050B

050SB

060SB

kW

5.2

8.0

10

12

12

15

BTU/h

18000

26000

35000

42000

42000

55000

kW

5.5

8

11

13.5

13.5

17.5

BTU/h

18500

29000

37500

46000

46000

60000

Cooling Power Input

kW

1.8

2.7

3.7

4.2

4.2

5.5

Heating Power Input

kW

1.85

2.8

3.8

4.3

4.3

6

A

8.2/8.4

12.2/12.7

16.8/17.0

19.0/19.5

7.5/8.0

9.6/10.5

V/Ph/Hz

220/1/50

220/1/50

220/1/50

220/1/50

380/3/50

380/3/50

1

1

1

1

1

1

Compressor

Rotary

Scroll

Scroll

Scroll

Scroll

Scroll

Fan Number

1

1

2

2

2

2

Cooling Capacity

Heating Capacity

Running Current (Cooling/Heating) Power Supply Compressor Number

Fan Power Input

W

120

120

120x2

120x2

120x2

120x2

Fan rotate speed

RPM

850

850

850

850

850

850

dB(A)

54

56

59

59

59

59

Water Pump Input

kW

0.1

0.2

0.4

0.4

0.4

0.4

Water Pump Pressure

m

6

8

10

10

10

10

Water Connection

Inch

3/4"

1"

1"

1"

1"

1"

Water Flow Volume

m3/h

0.9

1.3

1.7

2.3

2.3

2.5

Water Pressure Drop

kPa

17

17

29

32.5

34

37

Capacity Of Water Storage

L

15

23

32

32

32

32

Unit Net Dimensions (L/W/H)

mm

1110/470/650

1110/470/850

1110/470/1250

1110/470/1250

1110/470/1250

1110/470/1250

Carton Packing Size (L/W/H)

mm

1250/500/700

1250/500/900

1250/500/1300

1250/500/1300

1250/500/1300

1250/500/1300

Net Weight

kg

90

110

140

150

150

160

Shipping Weight

kg

110

120

160

165

165

175

Noise

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Heat pump concepts and energy issues Air-source heat pumps extract heat from the external air. The essential components of an air-source heat pump are heat exchangers (through which energy is extracted and emitted) and a means of pumping heat between the exchangers. Almost all contemporary heat pumps are based on a vapour compression refrigeration cycle. A vapour compression schematic is shown above. Working fluid evaporates by extracting heat from a low temperature source (external air); the vapour is compressed mechanically to a high pressure, high temperature gas and then condenses back into a high pressure liquid state giving up its latent heat as useful heat (to either an internal air distribution mechanism or a hydronic circuit). The liquid then expands through a valve or other restriction such as a capillary tube causing a drop in pressure and partial vaporisation before re entering the evaporator for the cycle to be repeated. The compressor is usually driven by electricity. Air-source heat pumps are classified as either air-to-air or air-to water depending on whether the heat distribution system in the building uses air or water. The effectiveness of the heat pump is measured by the ratio of the heating capacity to the effective power input, usually known as the co efficient of performance (CoP). There are other forms of heat pumps used for heating buildings. A common one is the water loop type where heat is extracted from a water source. This can be a closed loop with separate facilities to input or extract heat from the closed loop. These are often referred to as a Versatemp system (after the original brand name). An open loop system would extract heat from a lake, dock or river.

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Advantages Air-source heat pumps can have a number of environmental and operation advantages. These are:  More heat is supplied to the building than energy consumed by the heat pump  No combustion or explosive gases within the building  No flue or ventilation requirements  No local pollution  Carbons savings possible over gas-fired condensing boilers  Long life expectancy – similar to gas-fired boilers  Low maintenance costs  Faulty operation is unlikely to create a safety hazard, unlike gas-fired equipment which potentially could be fatal. An air-source heat pump with a CoP of three will supply three kilowatts of heat energy for the consumption of one kilowatt of electricity. If the heat pump is replacing, or being used as an alternative to electric space heating, the use of the heat pump will offer significant carbon savings. However, if the heat pump is used in place of a modern gas-condensing boiler, the carbon savings may be much less clear-cut. There are many published claims over comparisons between gas fuelled condensing boilers and electrically-driven heat pumps with regard to carbon and cost savings. These are highly influenced by assumptions on seasonal performance, the utility unit costs and the carbon content of the electricity used. This stems from the fact that electrical energy obtained from the National Grid is relatively carbon inefficient when the whole mix of generation sources is taken into consideration (along with distribution losses over the grid) compared with direct comparisons using solely nuclear or renewable sources. It is arguable that comparisons should be made on purely gas-derived electricity. As a general observation, although cost comparisons between gas fired condensing boiler systems and electrically-driven heat pump systems may show marginal savings, carbon savings are typically in the region of 20%.

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Benefits  Can be used for space heating and domestic hot water  Avoids the need and cost associated with underground coils for ground-source heat pumps  Proven technology

Limitations  Lower CoP than ground-source heat pumps  Low external air temperatures will reduce CoPs and reduce the heat pump’s output  Need to defrost when working at low external temperatures will also degrade overall performance  The achievement of optimum CoPs will require relatively low heating-circuit flow temperatures and can impact domestic hot water generation  Repair costs can be higher than conventional gas-fired boiler systems.

A second major form of heat pump used for heating buildings is a groundsource system where heat is extracted from the ground. The main advantage of air-source heat pumps over ground-source heat pumps is their lower installation cost. A ground-source heat pump requires either a network of underground coils sometimes referred to as a ―slinky‖ or bore holes containing vertical heat exchangers that are used to extract heat from the ground. This presents a number of issues: the cost associated with the ground works in order to lay the ground collector or create the bore holes is relatively high, the available ground may not be suitable, and the disruption associated with the ground works may not be acceptable. By comparison air-source heat pumps extract the heat directly from the outside air and so avoid these potential problems but may not be as efficient. ©ESPApril2010

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The potential downside associated with extracting heat from external air is the effect on CoP. During the heating season the outside air temperature is often less than the ground temperature (at a depth at which heat is extracted by a ground-source heat pump). This lower temperature has the effect of reducing the CoP. Although some manufacturers of air-source heat pumps quote CoPs of up to four, care is needed to understand the rating conditions at which the CoP is stated compared with actual climatic conditions. The relevant test standard for most packaged heat pumps is BS EN 14511. For an air-to-water heat pump the standard specifies test conditions of 7°C outdoor air temperature (source temperature). At external air temperatures less than this, the CoP will be reduced as will the heating output of the heat pump. Depending on the application this reduced heat output could be significant, such as during a cold winter morning when building pre-heat is required. A further factor influencing the CoP of a heat pump is the sink temperature (the temperature of the supplied heated air or circulated water within the building). For an air-to-water heat pump BS EN 14511 specifies a return and flow temperature of 40°C and 45°C respectively. At temperatures higher than these the CoP (and heat output) will reduce. This means that heat pumps, although potentially suited to low temperature heating systems (such as underfloor heating), have poor CoPs when used with conventional hydronic heating systems with circulation temperatures of 60°C or higher. Test conditions and hence manufacturer’s quoted CoP data can differ significantly from actual design and operating conditions encountered. A more useful indicator of a heat pumps performance is the seasonal performance factor (SPF). This is the ratio of actual heat delivered over an entire heating season compared with the actual energy used to drive the heat pump over the entire season. There are various ways in which a manufacturer’s test data can be combined with climatic data to estimate the SPF, but this would require detail on part-load operation at various external conditions which is not often easily available. SPF cannot be calculated from test data obtained in accordance with BS EN 14511.

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System types Air-source heat pumps can be categorised depending on how the extracted heat is used within a building. The two types of air source heat pumps are airto-air heat pumps and air-to-water heat pumps. Air-to-air heat pumps are intended to directly heat the air within a building. Heat is extracted from the external air via an external unit housing the evaporator. The internally located condenser heats the air where it is supplied to the building. Where more than one area within the building is to be heated, or where the area is large, an air distribution system can be used to supply the air. Alternatively, multiple internal units can be used to heat different areas. An air-to-air heat pump may be a dedicated heat pump package providing heating only, but split, multi-split and variable refrigerant volume (VRF) comfort cooling systems can also be thought of as heat pumps if they have the ability to operate in reverse and provide heating as well as cooling. Split systems are made up of two basic components: one or more indoor room units and an outdoor unit that extracts heat from the exterior when the system is in heating mode. The indoor and outdoor units are linked by pipes which transport refrigerant between the units. On multisplit units, each indoor unit is connected to the outdoor unit by dedicated pipework. VRF systems are essentially a more sophisticated split system using a series of parallel connected indoor units – essentially a ladder type network of pipework. The difference from a split system is the ability in a single system, to provide heating or cooling from each of the indoor units on an individual basis. VRF systems have basically three formats; cooling only, heating or cooling systems, and simultaneous heating and cooling systems. This latter system is very numerous in the UK and is well suited to the UK’s variable maritime climate. Split systems are not capable of servicing simultaneous heating and cooling requirements. An advantage of air-to-air heat pumps over air-to-water heat pumps is the lower sink temperature (the temperature of the air passing over the condenser coil – typical values might be on at 18°C and off at 28°C). This results in a higher CoP and increased heat output. (CoPs rise with reduced difference between source and sink temperatures.) ©ESPApril2010

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Air-to-water heat pumps use water as the heat sink. The heated water can be used for space heating or domestic hot water at typically 40°C and 45°C. Design custom and practice in the UK for conventional gas-fired water based heating systems is typically 71°C to 82°C. This has implications for heat exchanger sizing comparisons between the two systems and even distribution system selected. For example underfloor heating suits heat pumps very well, while compact, simple steel panel radiators suit the higher distribution temperatures. Air-source heat pumps, whether using air or water as the thermal sink, require the use of a defrost cycle. Frost accumulates on the outdoor coil when the exterior air temperature is less than approximately 5°C (the exact temperature will depend on the moisture content of the air). Defrost cycles are performed automatically, usually by reversing the heat pump for a period of time during which no heat is produced, and typically a few minutes in every 30 minutes operation in cold weather. When selecting an air-source heat pump it is advantageous to select a unit with a high CoP. The main sources of electrical consumption in an air-source heat pump are the compressor’s electrical motor and the motor driving the fans. Traditionally these motors were alternating current (AC) motors, however many heat pump manufacturers now provide direct current (DC motors. DC motors can offer significant energy savings over simple AC motors due to their higher efficiency. In addition, direct electronic commutation (EC) commonly used with DC motors allows for direct variable speed control that can further reduce energy consumption. A further benefit of DC motors is their lower running temperature, resulting in improved motor longevity. The Enhance Capital Allowance scheme for energy efficient products provided tax advantages to end users for purchasing high efficiency units. Heat pumps are one of the technologies covered and their website www.eca.gov.uk lists many air source heat pumps that use energy saving components such as variable speed fans and compressors. As an example, the minimum CoP under the English and Welsh Building Regulation is 2·2, so to ©ESPApril2010

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be included on the Energy Technology List for an enhanced capital allowance, the COP must exceed 3·4 (over 50% better). The EU F-Gas Regulations imposes obligations on operators and contractors relating to mechanical cooling systems and heat pump systems that use fluorinated greenhouse gas-based refrigerants. Fgases typically used in heat pumps include HFC refrigerants such as R134a, R407C, and R410A. For systems with over 3 kg of refrigerant charge (6 kg if hermetic - this might equate to a unit heating capacity of 20 kW), operators must:  Prevent leakage, and repair any leaks as soon as possible  Arrange proper refrigerant recovery by certified personnel during servicing and disposal  Carry out leak checks to a defined schedule  Ensure that only certified competent personnel carry out leakage checks  Maintain records of refrigerants and of servicing.

Where to use Space heating As has been discussed an air-to-air heat pump can heat the air inside a building directly or via an air distribution system. Air-to water heat pumps by comparison require the heat pump to be integrated with a hydronic heating system. Such a heating system could, for example, comprise a network of radiators or an underfloor heating system. When considering a heat pump in conjunction with a hydronic heating system a number of factors should be taken into account. The heat output from a network of radiators will depend on the flow temperature and the surface area of the radiators. High flow temperatures will result in a lower heat pump CoP, while lower flow temperatures will require greater radiator surface area. In many applications the provision of sufficient radiator surface areas in order to provide an acceptably high CoP will be challenging (in terms of cost, space allocation, and aesthetics). Underfloor heating offers a more practical solution due to the large heating surfaces (a network of pipes imbedded in the floor) and low flow temperature, typically 30°C/35°C. ©ESPApril2010

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When considering the potential use of an air-source heat pump, building preheat should be taken into account. The majority of buildings are not continuously heated and will therefore require to be pre-heated before they are occupied, or in the case of domestic buildings, before the occupants get up. During periods of low external air temperature (such as a cold winter’s morning) the output from an air-source heat pump will reduce. In some extreme circumstances the heat pump may not have the capacity to provide a sufficiently fast building warm-up. Some systems have electric heating top-up capability to cater for these extremes. These may be more typical of systems available in Nordic countries.

Domestic hot water heating The heat generated by an air-source heat pump can be used to provide domestic hot water (DHW), heated water used for washing and cleaning purposes. In order to avoid the occurrence of Legionnaires’ disease, DHW must be heated to 60°C. A heat pump operating at a temperature as high as this will have a relatively poor CoP. One approach may be to use the heat pump to pre-heat the DHW, then to use an additional heat source to boost the temperature to 60°C. The choice of this additional heat source will affect the carbon efficiency of the system. From a carbon emission perspective the least efficient choice is electric heating elements supplied with electricity from the National Grid. This equates to using the heat pump to fully heat the water, operating with a CoP of one. An alternative approach could be to use a conventional condensing boiler to boost the water temperature. However, this would have associated high capital and maintenance cost penalties unless the boiler was used for other purposes. Other alternatives could include renewables such as solar or wind energy, but their ability to provide the boost function will be limited due to climatic and seasonal restrictions and careful design is needed to ensure full integration.

Where to use Space heating As has been discussed an air-to-air heat pump can heat the air inside a building directly or via an air distribution system. Air-to water heat pumps by comparison require the heat pump to be integrated with a hydronic heating system. Such a heating system could, for example, comprise a network of radiators or an underfloor heating system.

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When considering a heat pump in conjunction with a hydronic heating system a number of factors should be taken into account. The heat output from a network of radiators will depend on the flow temperature and the surface area of the radiators. High flow temperatures will result in a lower heat pump CoP, while lower flow temperatures will require greater radiator surface area. In many applications the provision of sufficient radiator surface areas in order to provide an acceptably high CoP will be challenging (in terms of cost, space allocation, and aesthetics). Underfloor heating offers a more practical solution due to the large heating surfaces (a network of pipes imbedded in the floor) and low flow temperature, typically 30°C/35°C. When considering the potential use of an air-source heat pump, building preheat should be taken into account. The majority of buildings are not continuously heated and will therefore require to be pre-heated before they are occupied, or in the case of domestic buildings, before the occupants get up. During periods of low external air temperature (such as a cold winter’s morning) the output from an air-source heat pump will reduce. In some extreme circumstances the heat pump may not have the capacity to provide a sufficiently fast building warm-up. Some systems have electric heating top-up capability to cater for these extremes. These may be more typical of systems available in Nordic countries.

Domestic hot water heating The heat generated by an air-source heat pump can be used to provide domestic hot water (DHW), heated water used for washing and cleaning purposes. In order to avoid the occurrence of Legionnaires’ disease, DHW must be heated to 60°C. A heat pump operating at a temperature as high as this will have a relatively poor CoP. One approach may be to use the heat pump to pre-heat the DHW, then to use an additional heat source to boost the temperature to 60°C. The choice of this additional heat source will affect the carbon efficiency of the system. From a carbon emission perspective the least efficient choice is electric heating elements supplied with electricity from the National Grid. This equates to using the heat pump to fully heat the water, operating with a CoP of one. An alternative approach could be to use a conventional condensing boiler to boost the water temperature. However, this would have associated high capital and maintenance cost penalties unless the boiler was used for other purposes. Other alternatives could include renewables such as solar or wind energy, but their ability to provide the boost function will be limited due to climatic and seasonal restrictions and careful design is needed to ensure full integration.

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Where an air-source heat pump is to provide space heating and domestic hot water consideration should be given to the capacity of the heat pump and whether it has the duty to provide both functions simultaneously.

Heat recovery Heat recovery can be used to boost the efficiency of an air source heat pump. Where a building has a mechanical ventilation system, warm air is expelled. This relatively warm air can be used as the heat source for the heat pump. The expelled air will be warmer than the exterior air during the heating season. By extracting heat from the expelled air as opposed to the exterior air, the temperature differential between the heat source and sink will be reduced resulting in a higher CoP. Where the expelled air has high moisture levels, for example a swimming pool air extract system, the latent heat can be used to further boost the overall efficiency (but defrosting may be more frequent, and contamination of the air with chlorine may be an issue related to the materials used in the heat exchangers). When providing space cooling some split or VRF systems allow for the recovery of expelled heat to be used to pre-heat DHW.

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Application considerations  Check that an appropriate heat pump unit is used for the intended application.  Check that the heat pump can satisfy the heat requirement over the full range of anticipated operating conditions.  Consider that the CoP and heat output will decrease with reducing external air temperature (source temperature).  Consider that the CoP and heat output will decrease with increasing internal supply temperature (sink temperature).  The frequency and duration of defrosting and the energy required to achieve defrost should be considered. Check that the energy required for defrost is taken into account when estimating the overall power consumption.  The potential noise problems arising from the use of air-source heat pumps needs to be considered early in the design process (primarily noise from the evaporator fan/motor and compressor).  Check that there will be sufficient clearance around the unit for proper airflow and service access.  Consider that oversizing of heat pumps will cause excessive cycling, reduced performance and reduced life.  Consider what supplementary heating may be required. Avoid the inefficient use of supplementary heating. This can give rise to running costs in excess of predictions.

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We have units available in stock.

The

units comply with all relevant European standards, including EN14511- both in terms

of

operating

manufacturing

efficiency

process

as

and our

manufacturing facilities are ISO 9001 accredited. The units have a COP of 3.24 based upon testing against the criteria set out in EN14511 - based upon an ambient temperature of 1/2°C (rather than 6/7—meaning that the units are extremely efficient) and use R407c refrigerant. Full specifications can be seen in the table below/attached. Please also note: Our heat pumps are tested and certified by independent bodies

approved

and

accredited

by

UKAS

(the

United

Kingdom

Accreditation Service) to carry the following quality marks covering safety, efficiency and/or Standard compliance in the UK, Mainland Europe, Asia, North America and Canada - CE mark, CB, CCC, GS, UL and EVC marks and our manufacturing facilities are certified to ISO 9001. All of our products are proven by independent bodies to be of the highest quality and efficiency and carry the above quality marks when sold anywhere across the globe. The units are extremely quiet when running less than 50db. The savings that can be made on fuel costs is up to 75% and the units are designed to have a life span of 20 years with no substantial annual maintenance required or recommended. All component parts of the units are from household name manufacturers such as the Danfoss heat exchanger, Wilo water pump, Copland or Hitachi scroll compressor and chiller 300 micro controller, so reliability and longevity is guaranteed. The units deliver market leading performance at very low prices. Our units are available for you to see in a fully working environment so that you can get a feel for the units and hear for yourself the low noise level generated by the units when running under full operational loads. ©ESPApril2010

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Earth Save Products Ltd., Woodside Farm, Long Wittenham, Abingdon, Oxfordshire, OX14 4PT Tel no: 0844 414 2845 | 01235815569 Email: [email protected] Web: www.esavep.com ©ESP2010

©ESPApril2010