Trane TRG-TRC011-EN manual Changeover

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.

32 TRG-TRC011-EN