period two
Absorption Chiller Types
notes
steam or | condenser |
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hot water |
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generator |
| cooling |
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| water |
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evaporator | chilled |
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heat | water |
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expansion |
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exchanger |
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| device |
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absorber |
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absorber | evaporator spray pump |
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spray pump | generator pump | Figure 23 | |
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Let us review Period One briefly. In the generator, dilute solution absorbs heat from the steam or hot water, causing 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 resulting hot refrigerant vapor migrates to the cooler condenser, where heat transfers from the refrigerant vapor to the cooling water, causing the refrigerant to condense. The resulting condensed liquid refrigerant flows through an expansion device, causing a pressure drop that reduces the refrigerant pressure and temperature to the desired evaporator conditions. The cooled mixture of liquid and vapor refrigerant then flows into the evaporator pan, from which the evaporator spray pump continuously pumps the liquid refrigerant and sprays it over the tubes. As heat transfers from the water to the cooler refrigerant, the refrigerant boils (vaporizes) and the resulting refrigerant vapor is drawn into the absorber.
Inside the absorber, the refrigerant vapor is absorbed by the lithium bromide solution. As the refrigerant vapor is absorbed, it is also condensed, thereby releasing heat to the cooling water. The absorber spray pump mixes concentrated absorbent solution (returning from the generator) with dilute solution (from inside the absorber) and delivers this intermediate solution to the absorber sprays. To complete the cycle, the generator pump returns the dilute absorbent solution to the generator to be reconcentrated. This cool dilute solution passes through a heat exchanger to be preheated by the hot concentrated solution returning from the generator.
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