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Rajesh Dixit, Johnson Controls, Inc. |
Absorption heat pumps can be used for generating medium temp hot water (up to 195F) for district heating applications using a low grade waste heat source and a high grade heat source. With about 40% of heat coming from a very low grade source, which otherwise would be rejected to atmosphere, the coefficient of performance is about 1.7 and the economics becomes quite attractive. This source could be geothermal heat or process heat or even a condenser water loop by bypassing a cooling tower. Heat pumps have also been successfully utilized in waste to energy plants.