Heat pumps are devices that allow us to use the surrounding thermal energy for heating purposes. Although their installation is quite expensive, but incurred expenditure will quickly return. Heat pumps are among the cheapest in the operation of central heating and hot water systems.Principle of operation
The heat pump consists of four basic elements: the heat exchanger from the surrounding, the compressor, the heat exchanger for the installation and the expansion valve. All these elements form a hermetically sealed system, filled with a substance that transports heat. This substance is a refrigerant with very low evaporation temperature. Thanks to this property it can turn into steam even at low environmental temperatures, eg in winter.The refrigerant in the form of steam is sucked in by the compressor where it compresses. During this process, the vapor volume decreases and the pressure increases simultaneously, accompanied by an increase in temperature. An analogous reaction can be observed when pumping bicycles - when they are inflated the tip of the pump becomes much warmer.The refrigerant vapor is then pushed into the exchanger, where it gives off heat to the water circulating in the c.o. Conversely, the temperature of the steam after heat transfer is lowered, which causes it to condense.Then the liquefied refrigerant is routed to the so-called. An expansion valve from which it exits through a small opening at a pressure greater than atmospheric pressure (similarly as cosmetic deodorants). The expansion of the medium is accompanied by so much high pressure drop and temperature drop that in contact with the heat from the environment again evaporates. And the process starts from the beginning.