Trane TRG-TRC011-EN manual Absorption System Fluids

period one

Absorption Refrigeration Cycle

notes

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◆Stable

◆Nontoxic

◆Low cost

◆Readily available

◆Environmentally friendly

◆High latent heat of vaporization

Figure 7

Absorption System Fluids

Probably the greater of these differences between the vapor-compression and absorption refrigeration cycles, however, is the types of fluids used. The vapor- compression refrigeration cycle generally uses a halocarbon (such as HCFC-123, HCFC-22, HFC-134a, etc.) as the refrigerant. The particular absorption refrigeration cycle discussed in this clinic uses distilled water as the refrigerant.

Distilled water is stable, nontoxic, low in cost, readily available, environmentally friendly, and has a relatively high heat of vaporization

(1000 Btu/lb [2326 kJ/kg]). The heat of vaporization is the amount of heat required to fully transform (evaporate) liquid to a vapor at a given pressure. For the water to be used as a refrigerant, the cycle must operate in a vacuum, that is, at a pressure below atmospheric pressure. This will be discussed shortly. Finally, large quantities of water are easily absorbed by the absorbent and separated within the absorption cycle.

Throughout the remainder of this clinic, when the term refrigerant is used, it refers to distilled water.

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