How do Ground Source Heat Pumps Work?

The Basics

You probably own a heat pump without realising it - a refrigerator is actually a type of heat pump. When used for heating, heat pumps save energy by extracting heat from an outside source, and delivering it for use within the building. They can be used for any normal heating need. This apparently magical technology is not new: in the 1950's several heat pumps were installed in a bid to save energy and fuel costs. One of the most famous of these was used to heat the Royal Festival Hall in London by extracting heat from the River Thames.

HOW CAN ENERGY BE EXTRACTED FROM COLD WATER?

Our natural sense of heat is based more on instinct than on science. Humans are warm-blooded and judge "heat" by comparing it by touch. Since our body temperatures need to be maintained within a few degrees of centigrade, our natural senses have evolved to make extremes of temperature uncomfortable. To us, a hot summer's day feels many times "hotter" than the freezing mid-winter. But in reality the Earth's surface does not vary in "heat energy" as much as we might imagine. Scientifically speaking, there is only 11% less energy in cold river water at 5°C (40°F) compared to hot bath water at 40°C (105°F).