An inventor has developed a refrigeration unit that maintains the cold space at −10°C, while operating in a 25°C room. A coefficient of performance of 8.5 is claimed. How do you evaluate this?
βCarnot = QL/Win = TL/TH - TL
= 263.15/25 - (-10) = 7.52
8.5 > βCarnot ⇒ impossible claim
