12th International Symposium on District Heating and Cooling

The <strong>12th</strong> <strong>International</strong> <strong>Symposium</strong> on District Heating and Cooling,September 5 th to September 7 th , 2010, Tallinn, Estoniaone thousand homes. However, the basic structure isalmost the same as that of western apartment buildingsexcept for the pipeline network between buildings andsubstation. In the past there was one substation in oneapartment complex. The substation has a minimum oftwo heat exchangers which are in general shell andtube type or plate type. Nowadays the number ofsubstations grows bigger and bigger. That means thatthe designer plans to install the heat exchangerseparately and respectively according to the buildingswhich stand nearby each other. The secondarypipelines have been said to have much heat loss inKorea. There have been a few studies related to heatloss from the secondary pipelines. It is very hard todistinguish between positive heat gain and heat lossfrom the pipelines installed within the buildings. If thepipelines are installed in the center of the building, theheat loss from the heating pipes or hot water supplypipes can be regarded as positive heat to theconsumer. But if the pipelines are installed near thebuilding surface, the heat from the pipes can beregarded as loss.Measurement and analysis of the heat loss fromseveral apartment complexes in Korea has been tried.The heat loss data from the several sites has beenstored and accumulated throughout the year. Asimulation method has been set up and the accuracy ofthe simulation has been investigated. Somealternatives to reduce the heat loss have beenprepared from the existing scheme. The simulationmethod and results have been presented in this paper.TYPE OF APARTMENT COMPLEXThe apartment complex was built and opened inNovember 2007. It has 8 buildings which arecomprised of 518 homes. Each home has 112 m 2 ofheating area. Fig. 1 shows the location and overallshape of the apartment complex which was chosento be measured and evaluated on the heat loss fromthe secondary pipelines. Many thermocouples andflow-meters were installed in the region of the pipelinesto collect information on heat demand pattern,temperatures and heat loss from certain regions to beevaluated.City water201202SupplementaryWaterHWRHWRHWRHWRHWS207205203HWRHWRHWRHWRHWSHWRHWRHWRHWRHWSCalorimeterM208206204Fig. 2 Secondary pipeline network from the substationANAYSIS OF HEAT CONSUMPTION PATTERN1) Space heating water flowrateSpace heating amount is being measured daily. Toomtemperature does not differ much between the homesin the apartment complex. Thus the temperaturedifference (ΔT) between inlet and outlet of the pipelineof individual homes remains fairly constant except inthe summer season. Therefore the heating water flowrate can be estimated from the following equationQ=CmΔT. In other word, the flow rate could beevaluated from the measured calorific amount. A goodexample of this is shown in Fig. 3.DHWRDHWSCHINASouthKOERANorthKOREAJAPANFig. 1 The location and the shape of the apartmentcomplexFig. 3 Temperature difference between supply and returnIn this study the flow rate was measured for the twomonths of November and December 2009 using theflow meter installed in the space heating water pipeline.And the hourly heating water flow rate of individualhomes for the year 2009 was extracted from thecomparison of the total measured amount and theindividual house measurement. Fig. 4 represents theannual heating water flow rate. Some differences existduring the cold winter season.106