The answer, of course, is to use the water in the mines which remains at a fairly constant temperature all year round as the heat source for a ground source heat pump or, strictly speaking, water source heat pump - the technology is the same. The One Show asked Ecoliving how we could best demonstrate exactly what is happening to convert the heat from the water at around 10°C into useful temperatures for heating and hot water. They wondered if we could show the process as simply as possible using everyday items.
Using a couple of fish tanks with coils and complete with thermometers, the technical team at Ecoliving put together a working model of how the refrigeration cycle works. This is the same process that takes place inside a heat pump. They created a representation of the refrigeration cycle including the other core components, a small compressor and an expansion valve. With the fish tanks representing the heat exchangers (evaporator and condenser) the model was filled with refrigerant and was then ready to go.
The model was used on the One Show to explain how a heat pump works. The key things making this process work are that the refrigerant has a very low boiling point and also that the pressure in the compressor raises the temperature of the refrigerant gas to useful temperatures. One unit of electricity to run the compressor can deliver up to 4 units of useful heat! Take a look and hopefully you will see how a heat pump works. If not let us know and we will be delighted to explain.