Trane TRG-TRC004-EN manual 5HYLHZ²3HULRG7KUHH, Vwhpohyhofrqwuro

period four

Review

notes

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Figure 54

Period Three considered the entire system and discussed how the capacity of the compressor is controlled to maintain desired space conditions.

In a constant-volume DX system, in order to respond to changing loads, the capacity of the compressor is controlled by directly sensing space temperature. In a VAV DX system, the capacity of the compressor is controlled by sensing the supply air temperature. In a chilled-water system, the capacity of the compressor is typically controlled by sensing the temperature of the water leaving the evaporator.

Period Three also discussed sensing suction temperature and hot gas bypass as methods for preventing evaporator freeze-up.

40 TRG-TRC004-EN