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Kasahara, Seiji; Murata, Tetsuya*; Kamiji, Yu; Terada, Atsuhiko; Yan, X.; Inagaki, Yoshiyuki; Mori, Michitsugu*
Mechanical Engineering Journal (Internet), 3(3), p.15-00616_1 - 15-00616_16, 2016/06
A district heating system for household heating and road snow melting utilizing waste heat from GTHTR300, a heat-electricity cogeneration design of high temperature gas-cooled reactor, was analyzed. The application area was Sapporo and Ishikari, cities with heavy snowfall in northern Japan. The heat transport analyses were performed by modeling components to estimate heat supply profile; the secondary loops between the GTHTR300s and the heat-application area; heat exchangers connecting the secondary loops to the tertiary loops of the district-heating pipes; and the tertiary loops between the heat exchangers and houses and roads. Though double pipes for the secondary loops were advantageous for having less heat loss and a smaller excavation area, these advantages did not compensate for the higher construct cost of the pipes. To satisfy heat demand in the month of maximum requirement, 520-529 MW of heat were supplied by 3 GTHTR300s and delivered by 6 secondary loops, 3,450 heat exchangers about 90 m long, and 3,450 tertiary loops. Heat loss to the ground from the tertiary loops comprised 80%-90% of the heat loss. More than 90% of the construction cost went into thermal insulators. The thickness and properties of the thermal insulator must be reevaluated for economical heat delivery.
Kasahara, Seiji; Murata, Tetsuya*; Kamiji, Yu; Terada, Atsuhiko; Yan, X.; Inagaki, Yoshiyuki; Mori, Michitsugu*
Proceedings of 23rd International Conference on Nuclear Engineering (ICONE-23) (DVD-ROM), 11 Pages, 2015/05
A heat transport analysis of a district heating and snow melting system in Sapporo and Ishikari, Hokkaido was carried out assuming application of waste heat from GTHTR300, a design of high temperature gas-cooled reactor. The following components in the system were modeled; pipelines of the water loops between GTHTR300 and heat demand district and heat exchangers to transport the heat from the water loops to water loops in the district. Double pipes for the pipeline has disadvantage that pumping electricity consumption was 2.74 times to that of single pipes due to pressure loss in annulus channel. On the other hand, the double pipe was advantageous in less heat loss and excavation load. Heat loss was 33% smaller because heat loss from inner tube was recovered in annulus channel. Excavation area was 23% smaller because water loop was made by one double pipe. Total heat loss from the GTHTR300s to the water loop in the district was 4.2% and ratio of pump electricity to power generation from the GTHTR300s was 0.8%. In January, the maximum heat demand in a year, 97.0% of the heat demand was supplied by 2 GTHTRs. Less distance between GTHTR300 and heat demand district from 40 km to 20 km would make cost of the heat transfer system 22% smaller.
Murata, Tetsuya*; Miwa, Shuichiro*; Sakashita, Hiroto*; Mori, Michitsugu*; Kasahara, Seiji; Yan, X.
no journal, ,
Application of a high temperature gas-cooled reactor (HTGR) for snow melting and district heating in Hokkaido was investigated. Concept design of a heat delivery system, modeling of pipes and a heat exchanger, calculation of heat supply amount from HTGR, and determination of location of the HTGRs were carried out. Sapporo and Ishikari were assumed as a heat demand district. To supply the maximum heat demand 435 MW in a year, 2 GTHTR300s, a kind of design of HTGR, were required. Though the distance from the GTHTR300 site and the heat demand district was 40 km, the temperature of the GTHTR300 waste heat was enough for the district heating. Double pipe for the heat transportation from the GTHTR300 to the district was advantageous for less heat loss and smaller excavation area. This system required 9 double pipes and more that 5000 heat exchangers.
