Carnot COP (Refrigeration)
Compute the maximum theoretical coefficient of performance (COP) of a refrigerator, COP = Tc/(Th − Tc), with temperatures in kelvin, where Tc is the cold-source (evaporator) temperature and Th the hot-source (condenser). It is the limit set by the 2nd law of thermodynamics: no real refrigerator can exceed it. The smaller the temperature difference between the sources, the higher the possible COP — which is why refrigerating to very low temperatures is so costly. Enter the cold and hot temperatures in kelvin.
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Carnot COP (refrigeration)
What is the best performance a refrigerator can theoretically reach? The answer comes from the Carnot cycle, the most efficient one allowed by the 2nd law of thermodynamics: COP = Tc/(Th − Tc), with the temperatures in kelvin. The COP (coefficient of performance) is the heat removed per unit of work spent — and, unlike the efficiency of a heat engine, it can be greater than 1 (a good air conditioner moves 3 to 4 times more heat than the electricity it draws!). The formula reveals a hard truth: the maximum COP falls rapidly as the difference Th − Tc widens. Cooling from 25 °C to 5 °C is cheap (small ΔT, high COP); cooling to −196 °C (liquid nitrogen) or to cryogenic temperatures is dramatically costly, because the Carnot COP collapses — and the real one sits lower still. That is why liquefying gases and reaching absolute zero demand so much energy. No real refrigerator beats the Carnot COP; it only gets close. Enter the cold and hot temperatures in kelvin.
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The results provided by this tool are for general informational and educational purposes only and do not constitute professional, financial, medical, legal, tax or accounting advice. Always confirm important decisions with a qualified professional and official sources.