http://www.commercialtemperaturesolutions.co.uk - Commercial Temperature Solutions

Heat pumps are more effective for heating than for cooling an internal space if the temperature differential is kept equal. because the compressor's input energy is also converted to useful heat when in heating mode, and is expelled together with the transported heat via the condenser to the internal space. But for cooling, the condenser is generally outdoors, and the compressor's dissipated work (waste heat) must also be transported to outdoors using more input energy, rather than being put to a useful purpose. For the same rationale, opening a food refrigerator or freezer actually heats up the room as opposed to cooling it because its refrigeration cycle rejects heat to the indoor air. This heat includes the compressor's dissipated work as well as the heat taken out from the inside of the appliance.
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