Types of Heat Pump
Heat pumps may be classified under the following types;
1. Air-to-air (air source to air heating system).
2. Air-to-water (air source to water heating system).
3. Water-to-water (water source to water heating system).
4. Water-to-air (Water source to air heating system).
5. Ground source to water.
The diagram below shows a heat pump using pipes buried
in sub-soil as the low grade energy heat source.
It is possible to use solar energy in the heat pump system, this is suitable in countries where solar radiation is not at consistently high levels throughout the year and the low temperatures achieved from solar panels can be upgraded to a higher more useable temperature for space heating.
Air to air heat pumps can be effective in their use of energy. But one problem with most heat pumps is that the coils in the outside air collect ice. The heat pump has to melt this ice periodically, so it switches itself back to air conditioner mode to heat up the coils. To avoid pumping cold air into the building in air conditioner mode, the heat pump also switches on electric heaters to heat the cold air that the air conditioner is pumping out. Once the ice is melted, the heat pump switches back to heating mode.