Beneficial use of rejected heat in municipal water supplies

The relatively low temperature of thermal discharges from steam-electric power plants makes waste-heat utilization difficult without modification of the power cycle and attendant reduction in electrical-energy generating efficiency. The in-situ beneficial use of waste heat by direct once-through condenser discharge into a municipal water supply is discussed. Computations are presented regarding the matching of flow rates, heat losses in distribution and energy savings. A number of benefits and penalties are also assessed qualitatively including legal and operational aspects and reliability. Especially attractive are improvements in generating efficiency, alleviation of water-pipe freeze up, savings in water-heater energy, and improvement in wastewater treatment effectivness. Disadvantages include the need for careful control of condenser water quality and the question of public acceptance of water heated by about 13/sup 0/C. Two cases with operating experience are briefly discussed, although the installations were not developed for energy conservation purposes.