Evaluation of Heat Energy Within Urban Water in Cold District

Abstract

This is a study on evaluation of heat energy within urban water in a cold district. We took Sapporo city as an example, and firstly clarified existing situations of heat energy of river water, ground water, city water and sewage. Secondly, these waters were examined as heat source of current systems to utilize water. In addition to enthalpy assessment like the above, thermal quality assessment was also made by means of performance indices based on the thermodynamics, through which waste heat of sewage treatment plants has been found the most useful. Lastly, we produced a map that shows reductions of primary energy consumption of areas of the city, in the case that each area is supplied with heat by a district heating system utilizing waste heat of a sewage treatment plant.