Trane trg-trc005-en manual Finned-Tube Evaporator Control, Face-Split Arrangement

period three

Evaporators

notes

Finned-Tube Evaporator Control

expansion valve

evaporator

liquid refrigerant

refrigerant vapor

Figure 31

Typically, an expansion valve is used to control the flow rate of refrigerant through the evaporator to maintain the proper amount of superheat, ensuring that the liquid refrigerant will be completely vaporized. Working in conjunction with the unloading or cycling compressors, the expansion valve allows the evaporator capacity to match the system load. The operation of the expansion valve will be discussed further in Period Four.

Face-Split Arrangement

distributors

Figure 32

When an evaporator contains more than one liquid-refrigerant distributor, it is split into independently-controlled sections, each being served by its own expansion valve. By turning on and shutting off these coil sections, the evaporator can further control its capacity to better match the system load.

The three common arrangements for splitting finned-tube evaporator coils include: face-split, intertwined, and row-split.

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