A comparison of the new hot water district heating system and the old steam district heating System that was replaced demonstrates tremendous improvement in energy efficiency. Overall efficiency has doubled (from 36 percent in 1979 to over 72 percent m 1995). In other words, District Energy is now supplying twice the useful energy for the same fuel input. This dramatic increase in energy efficiency is due to significant improvements in the distribution system and installation plant facilities and installation of the cogeneration system.
The cogeneration system operates at a combined energy efficiency of more than 70 percent. Single-use plants, such as electrical power plants, operate at an efficiency of only about 35 percent since the "waste heat' after the turbine is not utilized.
In addition to improvements in the district heating system itself; District Energy's customers have reduced their energy consumption by an average of 20 percent through conservation and by converting and up-grading their heating systems. Specific gains were achieved through improved temperature and flow control, reduced thermal losses due to lower temperatures, elimination of steam traps and overall modernization of building heating systems.
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