1) What is a Heat Pump?
A heat pump is a device that is able to transfer heat from one fluid at a lower temperature to another at a higher temperature.
Heat pumps owe their name to the fact that they allow heat to be carried from a lower to a higher temperature level, inverting natural heat flow which - as is well known - in nature tends to be from a higher to a lower temperature.
The function of the heat pump may therefore be compared to that of a water pump positioned between two water basins that are connected to each other but which are located at different altitudes: water will naturally flow from the higher to the lower basin. It is, however, possible to return water to the higher basin by using a pump, which draws water from the lower one