Heat pumps These are devices that can extract and amplify heat obtained from a source of thermal energy. There are several types of heat pump. All use the same basic principle of extracting heat from a source and concentrating it to obtain a higher temperature, usually then applied to water for domestic heating and hot water.The device which does this can be thought of as a refrigerator operating in reverse. It is powered by electricity, but the amount of heat energy delivered is several times more than the electrical energy consumed. The......