Heat Pumps
How a heat pumps works
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Underfloor heating, MVHR & heat pumps

 

How Does a Heat Pump Work?

 

The refrigerant in the heat pump evaporates (Boyles Law) at low temperatures, the source energy whether air or water routes through the evaporator (heat exchanger) where the refrigerant circulates. The refrigerant extracts the energy and the refrigerant changes from a liquid into a gas, a scroll compressor draws the refrigerant in and compresses it.

 

The increase in pressure raises the temperature. The compressor is of a suction gas cooled designed so the energy/heat of the electric motor is not lost but reaches the downstream condenser together with the compressed refrigerant. The refrigerant releases it's absorbed energy to the circulating system via the condenser to the circulating system hot water and heating circuit, The expansion valve deduces the pressure of the refrigerant for the process to start all over again.

 

The environment is full of energy you have to go as low as -273 °C before every last bit of energy is drained. With the aid of a heat pump, at least some of this natural energy can be harvested and utilised as heat for DHW and central heating. The efficiency of a heat pump is given by its co-efficient of performance (COP), which means the thermal output divided by the electricity consumed. The higher the source/environmental energy whether water or air the better the performance and higher COP.

Heat pump boreholes
Stiebel Eltron WPL 10 heat pump
Heat pump manifold for ground collector pipes
Stiebel eltron ACS kit
Stiebel eltron WPF 27 heat pump

Energy Sources for heat pumps.

Groundwater is a good store of solar energy, even on the coldest days in winter temperatures of +7 to 12 degrees centigrade are achieved, and this is where its advantage lies. The near constant temperature of this heat source enables the heat pump to achieve a favourable Coefficient of performance all year roundm. These systems must be notified to and possibly approved by your local water board.

Geothermal collectors at a depth of 1.2 to 1.5 metres the ground remains warm enough even on colder days, to enable an economical heat pump operation. However, this requires a property large enough to accomodate a pipe system for collecting the heat from the ground. You will need approximately 2 - 3 times as much ground as the area to be heated.

Geothermal probes that are set up to 100 metres deep into the ground require less space, they comprise of a probe foot (u-shaped) and endless vertical pipe manufactured from HDPE pipe. Several geohermal probes can be linked up in a single system. These systems must be notified to and possibly approved by your local water board.

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