on site generation - heat pump presentation feb11

8/7/2019 On Site Generation - Heat Pump Presentation Feb11

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On Site Generation

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Ground & Air Source

Heat Pumps

Copyright On Site Generation Ltd. Feb 2011Not to be copied without specific prior permission


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On Site Generation

What are they / howdo they work?

Different types

Heat Pumps

as c sys em es gnrequirements

Costs and savings

( and CO2)

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Background

A fridge is a heat pump

Heat sources ground, water,air, exhaust air

Solar energy not geothermalenergy

Very efficient form of electricheating

Best for well insulatedproperties

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On Site Generation

How heat pumps work

4Source: Dimplex


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Heat pump efficiency

Coefficient of Performance is the ratio of

Energy in : Energy out

CoP typically 2.5 5

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Improves with higher heatsource temperature

Improves with lower heat

distribution temperature ie minimise the

temperature increase of

the system


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On Site Generation

Ground / water source heat pumps

Source: Danfoss heat pumps 6


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Boreholes

Boreholes are generally 125mm in diameter, wide

enough to install two HDPE pipes 40mm in diameterwith a weighted U bend

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Drilling video

Danfoss video

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Trenched ground loop

The trenches should be 1m apart and 1-2m deep.

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Air source heat pumps

Source: Danfoss heat pumps 10


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On Site Generation

ASHP 14 kW

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ASHP 8.5 kW

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ASHP Location

Noise from the fan therefore avoid close neighbours /bedroom walls etc

Manufacturers will have requirements for margins.....

13Source: Mitsubishi


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Design and sizing

Heat pump should be designed to heat loss ofbuilding

New buildings will have SAP calculations or heat loss

Existing buildings use existing consumption of fuel

for heating or calculate heat loss (RdSAP modelling)

A rule of thumb : existing properties have a heat loss of 50-60 Watts per m2 offloor area

- new build 30-35 Watts per m2 of floor area15


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On Site Generation

Heat loss estimation

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Underfloor heating provides a large surface area forlow temperature heat transfer

Radiator sizes need to be increased for lower flow- -

Heating system selection

. .

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Renewable Heat Incentive

Proposed Tariff Tariff lifetime

Details of scheme to be confirmed

Proposed tariff rates (likely to change):

(pence/kWh) (years)

GSHP < 45 7p 23

ASHP < 45 7.5p 18

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On Site Generation

Typical ASHP 8.5 kW

Approx. 7,500 installed cost Anticipated space / water heating requirement ~ 15,000 kWh / year

Expected energy input to ASHP ~ 5,000 kWh / year (COP = 3)

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System Annual FuelCost

CO2 Emissions

ASHP 600 2.7 tonnes

Gas Boiler 660 2.8 tonnes

Oil Boiler 900 4 tonnes

Electric Heating 1,800 8 tonnes

Note: Assumes electricity @ 12p/kWh , gas @ 4p/kWh and oil @ 6p/kWh


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On Site Generation

Typical GSHP 12 kW

Approx. 15,000 (trenched ground loop)

Approx. 20,000 (borehole installed ground loop)

Space / water heating requirement ~ 30,000 kWh / year

Expected energy input to GSHP ~ 7,500 kWh / year (COP = 4)

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System Annual FuelCost

CO2 Emissions

GSHP 900 4 tonnes

Gas Boiler 1,320 5.5 tonnes

Oil Boiler 1,980 8 tonnes

Electric Heating 3,600 16 tonnes

Note: Assumes electricity @ 12p/kWh , gas @ 4p/kWh and oil @ 6p/kWh


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Maintenance

Heat pumps require minimal maintenance

Annual service, couple of hours ~ 200

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Planning and Building Control

GSHPs are permitted development. ASHPs require planning permission due to concerns

over noise from the fan.

A building warrant may be required for the heat pumpinstallation

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Considerations

Is the house well insulated? Space for ground loop / outdoor unit

Radiators vs. underfloor heating

What are the alternatives (gas, oil etc)?

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on site generation - heat pump presentation feb11

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