Trane TRG-TRC011-EN manual Direct-Fired Chiller

Page 32

period two

Absorption Chiller Types

notes

	condenser	low-temperature
	condenser	generator
		generator
	evaporator

absorber

	high-temperature	Figure 31
	generator	Figure 31
	generator

Direct-Fired Chiller

The indirect-fired absorption chillers discussed previously use steam or a hot liquid (such as water) as the energy source. In contrast, the high-temperature generator of a direct-fired absorption chiller uses the heat released by the combustion of a fossil fuel to boil off the refrigerant vapor.

Common fuels used to fire the burner in the high-temperature generator are natural gas, number 2 fuel oil, or liquid petroleum (LP). Additionally, combination burners are available that can be switched from one fuel to another. Typical COPs for direct-fired, double-effect chillers are 0.9 to 1.1 (based on the higher heating value, or HHV, of the fuel).

	high-		refrigerant vapor		condensed
	high-				refrigerant
	temperature
	temperature	refrigerant
	generator	refrigerant			condenser
	generator	vapor			condenser
		vapor
				low-temperature
				generator

Figure 32

The example direct-fired chiller shown here employs the reverse-series flow cycle. In the high-temperature generator, the intermediate solution absorbs heat that is generated by the combustion process. Similar to the indirect-fired, double-effect chiller, this transfer of heat causes the refrigerant to boil and

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 Absorption Refrigeration Cycle Period onePeriod 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 Absorption Chiller Types Period twoSingle-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 Capacity Control Period threePeriod three Energy valve Generator Crystallization 10C 37.8C Capacity Control Capacity Control Capacity Control Heat exchanger bypass Evaporator pan Purge System Isolation valve Maintenance Considerations Period fourPeriod four Maintenance Considerations Test run with alternate fuel, if dual-fuel burner Maintenance Considerations Maintenance Considerations Corrosion inhibitor and performance additive recommendations Application Considerations Period fiveCooling-Water Temperature Limitations Combination Chiller Plants 58F Special Considerations for Direct-Fired Chillers Application Considerations Equipment Rating Standards Review Period sixPeriod six Review Review Review Quiz Questions for PeriodQuiz TRG-TRC011-EN Answers Glossary Glossary Glossary Trane Company