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2.10 Heat Recovery from Chillers

This part of the Energy Efficiency Manual presents the energy conservation measures that apply to heat recovery from chillers, air conditioners, and other cooling machines. Air conditioning and refrigeration systems remove enormous amounts of heat. Usually, this heat is discarded. However, you may have applications where this heat can be used. The primary obstacle is the relatively low temperature of the recovered heat, which limits its value to applications such as preheating domestic water. There are steps you can take to increase the condensing temperature, but this involves a compromise with the efficiency of the cooling system.

In this Subsection, you will learn the methods of recovering heat from air conditioning and refrigeration systems. These include direct use of condenser water, auxiliary condensers, double-bundle condensers, condenser water heat exchangers, and desuperheaters.

Each type of cooling machine has different heat recovery characteristics. You will learn how to recover heat most efficiently from centrifugal, screw, reciprocating compressor systems, as well as absorption cooling systems. The heat recovery characteristics of different refrigerants are explained, with particular attention to ammonia refrigeration systems.

For applications where you can use large amounts of recovered heat, you will learn how to select and install special heat recovery chillers. Also explained are thermal storage systems that may increase the amount of heat that you can recover.