Explanation:

Vapour compression cycle is a thermodynamic cycle used in refrigeration systems to transfer heat from a lower temperature region to a higher temperature region. It consists of four main components: compressor, condenser, expansion valve, and evaporator.

The refrigerant enters the compressor as a low-pressure gas and is compressed to a high-pressure gas. The high-pressure gas then enters the condenser, where it releases heat to the surroundings and condenses into a high-pressure liquid. The high-pressure liquid then passes through an expansion valve, where it expands and reduces in pressure. The low-pressure liquid then enters the evaporator, where it absorbs heat from the surroundings and evaporates into a low-pressure gas. The low-pressure gas then enters the compressor again, and the cycle repeats.

The lowest temperature in the vapour compression cycle occurs in the evaporator. This is because the evaporator is where the refrigerant absorbs heat from the surroundings and evaporates into a low-pressure gas. This process causes a drop in temperature, making the evaporator the coldest point in the cycle. The temperature at the evaporator is typically below freezing, which allows it to absorb heat from the surroundings and cool the space.

In contrast, the condenser releases heat to the surroundings and operates at a higher temperature than the evaporator. The compressor and expansion valve are also high-temperature components, as they are involved in compressing and expanding the refrigerant.

Conclusion:

In summary, the lowest temperature in the vapour compression cycle occurs in the evaporator, as it is where the refrigerant absorbs heat from the surroundings and evaporates into a low-pressure gas. This process causes a drop in temperature, making the evaporator the coldest point in the cycle.