Trane TRG-TRC011-EN manual Review

Page 67

period six

Review

notes

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◆Vary solution flow to generator

◆Vary heat input to generator

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◆High-quality construction

◆Microelectronic controls

◆Automatic purge systems

◆De-crystallization devices

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Figure 71

Period Three explained the part-load operation of the absorption chiller. It described the use of energy valves, burner controls, throttling and bypass valves, and adjustable-frequency drives as methods for controlling the capacity on the chiller. Valves and AFDs are used to vary the flow rate of solution to the generator. Modulating energy valves and burner controls are used to vary the heat input to the generator.

It also introduced the concept of crystallization, which occurs when the absorbent solution becomes saturated and the salt begins to leave the solution as a solid. Causes of crystallization include: air and other noncondensable gases leaking into the chiller, cooling water that is too cold or that fluctuates in temperature too rapidly, and an electric power failure. In most modern absorption chiller designs, high-quality construction, smart microelectronic controls, and automatic purge systems are extremely effective in avoiding crystallization. Additionally, most absorption water chillers include devices that allow the chiller to recover in the event that crystallization does occur.

The operation of the purge system as a means of removing air and other noncondensables from inside the chiller was also presented.

62	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