Correct Answer - Option 3 : 5 kW

__Concept :__

**Coefficient Of Performance (COP) Or Energy Performance Ratio:**

It is defined as, **“The ratio of the desired effect to the work input.”**

\({{COP}} = \frac{{{{Desired\; Effect}}}}{{{{Work\;input}}}}\)

**Relationship between COP**_{HP }and COP_{Ref} (For same temperature Limits)

COP_{Heat Pump} = 1 + COP_{Ref}

__Calculation:__

__Given:__

Work Input = 1 kW, COP_{Ref }= 4.

COP_{Heat Pump }= 1 + COP_{Ref}

\(CO{P_{Heat\ Pump}} = \frac{{Desired\;Effect\;\left( {Heating\;Effect} \right)}}{{Work\;Input}}\)

Desired effect (Heating effect) = COP_{Heat Pump} × Work Input = 5 × 1 ⇒ 5 kW.