12th International Symposium on District Heating and Cooling

In case B, the analysis of operation characteristics fordrawing optimal system configuration becomes muchmore complex due to the existence of cooling load. Thesimulation results for gas turbine with 50% ofabsorption type cooling (i.e. 50% turbo type cooling)are given in the following.The <strong>12th</strong> <strong>International</strong> <strong>Symposium</strong> on District Heating and Cooling,September 5 th to September 7 th , 2010, Tallinn, EstoniaFig. 18 and Fig. 19 show the annual heat load andoperating conditions of thermal energy supply anddemand for on-site.As shown in Fig. 9, where the heating loads for case Aand B are compared, the heating load for a group ofnon-residential building composition is much smallerthan that of residential building composition. As aresult, the waste heat recovered from gas turbineoperation is sufficient enough to encompass the wholeheat loads in case B as shown in Fig. 18. In terms ofthermal networking operation, there is a great changein the pattern of system operation in that a largeamount of surplus heat energy is available even inwinter not to mention the intermediate seasons. Thismeans that a large amount of heat is flowing toward theexisting DHC system side as shown in Fig. 19, andthere will be serious effects on the operation of existingDHC system.(a) Heat(b) ElectricityFig. 20. Variation of operating conditions due to thermalnetworking operation on the existing DHC system sideThe effects of surplus heat energy on the operationconditions for the existing DHC system side are shownin Fig. 20. First of all, the considerable reduction for therate of CHP system operation during the intermediateseason is observed and it is also expected that the rateof operation for HOB is to be reduced in the winter asmuch as the amount of heat supply from the CHP onsite.Fig. 18. Heating load and recovered waste heat for gasturbine CHPFig. 21. Detailed variation of electricity production due tothermal networking operation on the existing DHC systemsideFig. 19. Annual thermal energy supply and demandoperating condition for newly developing areaConsequently, the heat production on the existing DHCsystem side is reduced to some extent as shown inFig. 20 (a) and it brings about the reduction of LNGconsumption for DHC system. In terms of electricityproduction as shown in Fig. 20 (b), there is a minorvariation for the production of it in winter despite theconsiderable thermal networking operation. It meansthat the CHP system on DHC system side is in fulloperation during winter regardless of thermalnetworking operation and the shortage of heat energy164