Question

In each cycle, the change in internal energy of the refrigerant when it leaves the compresser is 1.20×105 J . What is the work W done by the motor of the compressor?

Answer 1

Work done W = 1.20×10⁵ J

Step-by-step explanation:

Air conditioners operate on the same principle as refrigerators.

Consider an air conditioner that has 7.00kg of refrigerant flowing

through its circuit each cycle. The refrigerant enters the evaporator

coils in phase equilibrium, with 54.0% of its mass as liquid and the

rest as vapor. It flows through the evaporator at a constant pressure

and when it reaches the compressor 95% of its mass is vapor.

In each cycle, the change in internal energy of the refrigerant when

it leaves the compressor is 1.20×10⁵ J . What is the work done by the

motor of the compressor?

The compressor usually takes in low-pressure and low-temperature vapor and then compresses it adiabatically to high-pressure and high-temperature vapor.

Since the compressor performs an adiabatic compression, that means there is no exchange of heat while the refrigerant is in the compressor. Using the first law of thermodynamics to determine work done W.

ΔU = Q - W where ΔU is change in internal energy, Q is heat added which is zero as there is no exchange of heat and W is work done.

Therefore ΔU = W= 1.20×10⁵ J

Answer 2

The work done by the motor of the compressor is 1.20 x 10^5 J.

Step-by-step explanation:

As the change in the internal energy is given as 1.20 x 10^5 J, and as there is no amount of heat added in the system this is given as

`\Delta U=Q+W\\1.20* 10^5=0+W\\1.20* 10^5=W\\`

So the work done by the motor of the compressor is 1.20 x 10^5 J.