Mechanical Engineering - Heat Transfer, Refrigeration and Air Conditioning - Discussion

Yes, I too agree, the correct answer is: maintains different temperatures in the evaporator in proportion to load.

A thermostatic expansion valve (TXV) in a refrigeration system is designed to:

1. Regulate the flow of refrigerant into the evaporator.
2. Maintain a consistent superheat temperature (temperature above saturation) at the evaporator outlet.
3. Adjust to changing load conditions by varying the refrigerant flow.

The TXV ensures that the evaporator operates at the optimal temperature for the given load, which means:

- At low loads, the evaporator temperature is lower.
- At high loads, the evaporator temperature is higher.

This allows the system to maintain the desired cooling capacity and efficiency across varying load conditions.

The other options are not accurate:

- Ensures the evaporator is filled with refrigerant: This is not the primary function of a TXV.
- Suitable only for constant load systems: TXVs are designed to adapt to changing load conditions.

Thermostatic valve ensures pure vapour state of refrigerant to avoid compressor chocking since compressor can only handle gas.

The correct answer is C, because the responsibilities of the expansion valve is maintained different temperatures in the evaporator in proportion to the load.

Thermostatic valve ensure degree of superheat.

Automatic valve ensure constant pressure.