Explain why the thermal performance of the direct expansion

Explain why the thermal performance of the direct expansion coil is less than that of an equally zed flooded or liquid recirculated coil operating under the same conditions. Why is this important fo oils used in low-temperature applications?

Solution

Unlike D X evaporator, the flooded evaporatorprovides for the circulation of the refrigerant in the evaporator addition of separation or egalitarian. Liquid refrigerant enters the surge chamber through the dispenser and gravity causes it to flow down to the bottom pipe.

The coil surfaces in contact with the refrigerant at any load. This design produces a very good heat transfer, but requires a larger, more expensive hardware than D-X design. It also requires a large amount of the refrigerant. Steam (or gas)produced in the flooded evaporator separated from the liquid in the surge chamber. Liquid recirculation through the evaporator again, while a pair of exiled compressor suction action.

The flooded evaporator regulates the flow of the refrigerant by means of a float valve, or a similar arrangement. Float valve is used to maintain a given level of liquid in the surge chamber. The couple leaving the surge saturated, not overheat, as in the case of D-X evaporator.