As they condense, heat is released. Typical applications include commercial laundries and conveyor dishwashers. The recovered heat preheats fresh water before it goes into the domestic hot water tank reducing the energy needed to heat it to the required temperature. Buildings with steam systems can recover the heat from hot condensate when it is transferred to atmospheric pressure in the condensate receiver. A heat exchanger is installed in the condensate return.
Water is circulated between the heat exchanger and the hot water tank.
Other Types of Heat Recovery Cogeneration in commercial buildings can also reduce energy costs. When a natural gas or diesel engine-driven electric generator is used, the waste heat from the exhaust and the engine cooling water can be recovered by a waste heat boiler, and used for water and space heating. Gas turbines can also be used to drive a generator. Heat, recovered from the exhaust, can produce steam that drives a turbogenerator. Cogeneration units have a successful track record in a wide range of commercial applications, including restaurants, colleges, hotels, and hospitals.