How Heat Pumps Work
Heat Pumps are an extremely effective method of generating heat for your home. Using some motive power to run a refrigeration compressor, we can collect additional free heat from oudside sources such as the air, soil , rock or even the sea or lakes.
In the evaporator (heat exchanger) the energy transferes from the cold medium to the refrigerant. The refrigerant will then evaporate. The refrigerant is transported in the circuit by the compressor to increase the pressure and temperature of the refrigerant. In the condenser (heat exchanger) the refrigerant cools and condense. The energy is then transfered from the refrigerant to the heating system of the house, hot water system or airsystem The expansion valve regulates the mass flow of the refrigerant to maintain the pressure difference between the high pressure and the low pressure side.
All around us are sources of energy in the form of stored solar energy, which even if they have a low temperature can provide us with heat. But how can a few degrees above zero gives us energy to heat radiators and hot water. Let us explain!
Ground Source Heat Pumps
Surface soil heat
During the summer, solar heat is stored in the surface layer of the soil. Using that energy for heating is a practical approach for houses with a large plot. The amount of energy that can be extracted is greatest in soils with a high water content.
The heat is extracted from the soil by means of buried plastic tubing. An environment-friendly non-freezing liquid circulates in the tubing and delivers the collected heat to the heat pump. In the heat pump the heat is converted into high-grade heat for space heating and to produce hot water.
Heat from bedrock
Down in the bedrock there is a source of heat that stays at practically the same temperature all year round. Using heat from the rock is a secure, safe and environment-friendly way of heating all types of building, large and small, public and private.
The heat energy can be transferred to an existing, conventional, water-borne heating system and can also be used to produce hot water.
Drilling for Energy
The heat is collected from the bedrock and the groundwater through a borehole 4.5 to 6.5 inches in diameter. The depth of the borehole is determined by the amount of energy needed for heating. If the energy demand is great, several boreholes can be connected together. A specially made u-bend made from plastic with a weight attached is passed down into the borehole. Inside the collector tubing there is a frost-resistant liquid (cooling medium, brine). The system is completely sealed, so the cooling medium never makes contact with the groundwater.
To ensure that the groundwater is not contaminated by surface water running down into the borehole, a steel liner or casing which extends a short distance down into the borehole is installed. Grouting or rubber rings should be used to form a seal between casing and bedrock.