Answer
$\dot{W}_i=6.55\ kW$
Work Step by Step
The total heat input rate:
$\dot{Q}_H=3\times22000\ kJ/h=66000\ kJ/h$
$COP_{HP}=\dot{Q}_H/\dot{W}_i=2.8$
$\dot{W}_i=23571.4\ kJ/h=6.55\ kW$
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