A heat pump cycle operating at steady state receives energy by heat transfer fro
ID: 1588341 • Letter: A
Question
A heat pump cycle operating at steady state receives energy by heat transfer from well water at 10oC and discharges energy by heat transfer to a building at the rate of 1.2 × 105 kJ/h. Over a period of 14 days, an electric meter records that 1490 kWh of electricity is provided to the heat pump. These are the only energy transfers involved. Determine (a) the amount of energy that the heat pump receives over the 14-day period from the well water by heat transfer, in kJ, and (b) the heat pump’s coefficient of performance.
Explanation / Answer
a)
Number of hours in 14 days = 336 hours.
rate of heat transfer = 1.2*10^5 kJ/h
net heat transferred = 4.032*10^7 kJ.
b) The given electricity = 1490 kWh = 1490*10^3*3600 J = 5.364*10^9 J
So Coefficient of performance = 5.364*10^9/(4.032*10^10) = 0.133