Heat pumps

Heat pumps operate on several physical principles, but are classified according to their application (heat transfer, heat source, heat sink, or refrigeration machine). The compressor of a heat pump creates the pressure difference that allows the thermodynamic cycle to operate: it draws the refrigerant fluid through the evaporator, where the fluid itself evaporates at low pressure absorbing heat, compresses it and pushes it into the condenser where the fluid condenses at high pressure releasing the absorbed heat. After the condenser, the fluid passes through the lamination valve which brings it to a liquid/steam condition (reduces fluid pressure), then re-enters the evaporator starting the cycle again. The refrigerant changes state within the two exchangers: it changes in the evaporator from liquid to gaseous, in the condenser from gaseous to liquid.