Question

An automotive air conditioner produces a 1-kW cooling effect while consuming 0.75 kW of power. What is the rate at which heat is rejected from this air conditioner

Answer 1

Answer:

The rejected by the air conditioning system is 1.75 kilowatts.

Explanation:

A air conditioning system is a refrigeration cycle, whose receives heat from cold reservoir with the help of power input before releasing it to hot reservoir. The First Law of Thermodynamics describes the model:

$\dot Q_{L} + \dot W - \dot Q_{H} = 0$

Where:

$\dot Q_{L}$ - Heat rate from cold reservoir, measured in kilowatts.

$\dot Q_{H}$ - Heat rate liberated to the hot reservoir, measured in kilowatts.

$\dot W$ - Power input, measured in kilowatts.

The heat rejected is now cleared:

$\dot Q_{H} = \dot Q_{L} + \dot W$

If $\dot Q_{L} = 1\,kW$ and $\dot W = 0.75\,kW$, then:

$\dot Q_{H} = 1\,kW + 0.75\,kW$

$\dot Q_{H} = 1.75\,kW$

The rejected by the air conditioning system is 1.75 kilowatts.