Ground, groundwater and lake water heat
Ground, lake water and groundwater heat pumps provide basically similar energy savings – around 50–70 %.
This is the cross-section of a house. The house is heated by a ground source heat pump that also generates hot water. The heat is obtained from the coil of pipes buried in the ground. Illustration: Bo Reimerdahl
The ground source heat pump comprises a hose buried in the ground, with a liquid circulating in it. The loops are at a depth of 0.9 – 1.5 metres and the distance between them should be more than 1.5 m. The best soil for ground source heat is a wet clay soil. Ground source heat is very well suited if you have a large plot of land that you can conceivably dig up, such as pasture land adjoining the house.
In order to reduce the risk of damage to the hose, you can mark its location with plastic tape at about half the depth. Draw the run of ground source hose on a map. Also mark any joints. You will then know where the hose is if you were to make any extensive digging in the future.
A lake water source heat pump draws heat from lake or sea water by means of a hose laid on the lake bottom or in the bottom sludge. Keep the hose down with weights, so that it will not float up. Post a sign with the text “No anchoring” to reduce the risk of damage to the hose.
The groundwater source heat pump draws heat from the water in a groundwater well. The water is drawn up, cooled and infiltrated back into the ground through another well hole, for instance.
To install a ground source, groundwater source or lake water source heat pump, you must obtain permission from the municipal environmental and health protection boards.