Energy-efficiency specialists measure the heat Qh delivered by a heat pump and the corresponding electrical energy W needed to run the pump, and they compute the pump’s COP as the ratio Qh/W. They also measure the outdoor temperature, and they know that the pump produces hot water at Th = 52°C. The table below shows their results for Q and T. (a) Determine a quantity that, when you plot the COP against it, should give a straight line, (b) Make your plot, fit a straight line, and from it determine how the heat pump’s COP compares with the theoretical maximum COP.
Tc(°C) | −18 | −10 | −5 | 0 | 10 |
COP Qh/W | 2.7 | 3.2 | 3.6 | 3.7 | 4.7 |
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