Trane TRG-TRC011-EN manual Absorption System Fluids

Page 11

period one

Absorption Refrigeration Cycle

notes

▲

◆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.

6	TRG-TRC011-EN

Image 11

Contents Air Conditioning Clinic Absorption Water Chillers Absorption Water Chillers Preface Contents TRG-TRC004-EN Introduction TRG-TRC011-EN Period one Absorption Refrigeration CyclePeriod one Reject heat Heat energy Absorption System Fluids High affinity for water refrigerant Components of the Absorption Cycle Conditions Steam or Hot waterrefrigerant vapor Generator Condenser Refrigerant then flows into the evaporator pan Absorber spray pump Solution Heat Exchanger Dilute Generator pump Equilibrium Chart Heat Solution temperature Period two Absorption Chiller TypesSingle-Effect Chiller Absorber Evaporator spray pump Spray pump Generator pump Double-Effect Chiller Vapor Low Temperature condenser Cooling Generator Water Evaporator Absorber Low-temperature generator pump Generator pump Absorption Chiller Types Direct-Fired Chiller Evaporator High-temperature high-temperature Generatorgenerator pump Chiller/Heater Absorption Chiller Types Changeover Absorption Chiller Types Period three Capacity ControlPeriod three Energy valve Generator Crystallization 10C 37.8C Capacity Control Capacity Control Capacity Control Heat exchanger bypass Evaporator pan Purge System Isolation valve Period four Maintenance ConsiderationsPeriod four Maintenance Considerations Test run with alternate fuel, if dual-fuel burner Maintenance Considerations Maintenance Considerations Corrosion inhibitor and performance additive recommendations Period five Application ConsiderationsCooling-Water Temperature Limitations Combination Chiller Plants 58F Special Considerations for Direct-Fired Chillers Application Considerations Equipment Rating Standards Period six ReviewPeriod six Review Review Review Questions for Period QuizQuiz TRG-TRC011-EN Answers Glossary Glossary Glossary Trane Company