SIMULATION OF THE OPERATIONAL CONDITIONS OF WASTEWATER TREATMENT PLANTS TO MAXIMIZE ENERGY RECOVERY

第4回衛生工学シンポジウム（平成8年11月7日（木）-8日（金） 北海道大学学術交流会館） . 2 評価 . P2-1

Field performance of a polymer electrolyte fuel cell for a residential energy system

This paper describes the performance evaluation of a polymer electrolyte fuel cell for application to a hybrid utilization experiment involving renewable energy and a fuel cell for a residential energy system. First, experiments on characteristics of heat and power generation were carried out. Direct current electrical efficiency and heat recovery efficiency for a rated output operation were quite high: 42.5 and 49.2%, respectively. Second, characteristics of partial load, water temperature for heat recovery, start-up time, load following and exhaust gas were clarified. Finally, measurement of characteristics of a hot water tank was carried out, and it was proved that sufficient performance can be obtained even under continuous operation.Residential energy system Polymer electrolyte fuel cell Electric power Domestic hot water

Study on underground thermal characteristics by using digital national land information, and its application for energy utilization

This paper describes a method for evaluating characteristics of underground thermal properties and groundwater, whose evaluation is essential for designing systems of underground thermal energy utilization. First, the systems using underground thermal energy are classified into two categories: borehole system with indirect heat exchange, and aquifer system with direct use of underground water. These systems are also divided into thermal storage systems and heat source/sink systems. Second, the characteristics of the underground in Japan are analyzed by using a geographical information system (GIS) and hydrogeological information. Regulations on environmental protection, such as those relating to national parks for instance, and the distribution of thermal energy demand eliminate 77% of Japan from consideration for underground thermal energy utilization. Areas limited to borehole thermal energy utilization account for 17% of areas where underground thermal energy can be used, with the remaining 74% suitable for both boreholes and aquifers. Finally, we estimate the thickness of aquifer and groundwater velocity in Sapporo. We find that most parts of Sapporo are suitable for aquifer thermal energy storage (ATES).