Trane TRG-TRC011-EN manual Changeover

Page 37

period two

Absorption Chiller Types

notes

 

changeover

 

valve

 

refrigerant

 

vapor

 

hot

 

water

 

evaporator

high-temperature

absorber

generator

Figure 37

 

An alternate method is to use the evaporator as a condenser in the heating mode. In this example chiller, by switching the cooling/heating changeover valve the chiller switches to heating mode, and hot water can be delivered using the same piping system that was used to supply chilled water in the cooling mode. The cooling tower and refrigerant pumps can typically be shut off.

In the direct-fired high-temperature generator, heat that is generated by the combustion process causes the refrigerant to boil and separate from the absorbent solution. As the refrigerant boils away, the absorbent solution becomes concentrated and returns to the absorber.

The refrigerant vapor produced by the high-temperature generator flows into the evaporator. Heat is transferred from the hot refrigerant vapor to the water flowing inside the evaporator tubes, causing the refrigerant to condense on the tube bundle and fall into the evaporator pan. This condensed liquid refrigerant then overflows into the absorber section where it is absorbed by the lithium bromide solution.

The resulting dilute absorbent solution is preheated as it is pumped through the low- and high-temperature heat exchangers, eventually returning to the high- temperature generator to repeat the cycle.

The advantage of this design is that no additional bundle is required for heating mode. This chiller, however, can only operate in cooling mode or heating mode—no simultaneous operation is possible.

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TRG-TRC011-EN

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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
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