A heat pump has a heating capacity of 16 kW and a cooling capacity of 12 kW. It operates 1200 h in heating mode with a COP of 4 and 900 h in cooling mode with a COP of 3. Calculate the compressor input power, the amount of useful heat produced during heating and cooling periods, respectively, and

Question

A heat pump has a heating capacity of 16 kW and a cooling capacity of 12 kW. It operates 1200 h in heating mode with a COP of 4 and 900 h in cooling mode with a COP of 3. Calculate the compressor input power, the amount of useful heat produced during heating and cooling periods, respectively, and the average COP for the year.

Accepted Answer

1. Heating mode of operation ([latex]Q_{c}[/latex] = 16 kW, COP = 4 and [latex] au_{c}[/latex] = 1200 h)
a. Compressor input power

[latex]P_{\mathrm{cr}}=Q_{\mathrm{c}}/\mathrm{COP}=16/4=4\,\mathrm{kW}[/latex]

b. Useful heat produced in the condenser (for heating)

[latex]Q_{\mathrm{heat}}=\mathrm{t_{c}}Q_{\mathrm{c}}=1200*16\mathrm{~kW}=19,200\mathrm{~kWh}[/latex]

2. Cooling mode of operation ([latex]Q_{ev}[/latex] = 12 kW, COP = 3 and [latex] au_{ev}[/latex] = 900 h)
a. Compressor input power

[latex]P_{\mathrm{cr}}=Q_{\mathrm{ev}}/{\mathrm{COP}}=12/3=4{\mathrm{~kW}}[/latex]

b. Useful heat produced in the evaporator (for cooling)

[latex]Q_{\mathrm{cool}}=\mathrm{\mathrm{t}{_{ev}}}Q_{\mathrm{ev}}=900\;{\ast}\;12\;\mathrm{kW}=10,800\;\mathrm{kW}\mathrm{h}[/latex]

3. Average COP over the year of operation

[latex]\mathrm{COP}_{yr}=(Q_{\mathrm{heat}}+Q_{\mathrm{cool}})/(\mathrm{t_{c}}+\mathrm{t_{ev}})P_{\mathrm{cr}}=(19,200+10,800)/[(1200+900)]\,{\mathrm{\ast}}\,\,4]=3.57[/latex]

Question 14.8: A heat pump has a heating capacity of 16 kW and a cooling ca......

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