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, EstoniaTable 3 Heat loss comparison due to variousparametersHeat loss comparisonPresent pipe of insulation thickness 40 mm 100%Downsizing nominal diameter by 1 level 88.7%Insulation thickness 50 mm 86.1%Insulation thickness 60 mm 75.5%Closed-Cell Elastomeric thermal insulation 89.3%Pipe diameter downsizing + insulationthickness 50 mmPipe diameter downsizing + insulationthickness 60 mmCONCLUSION76.7%67.6%Present scheme for the secondary pipelines isevaluated to have 14% annual heat loss based on thetotal heat supply to the apartment complex. This is avery large amount when we consider that the primarydistrict heating pipeline has only about 4 to 5% annualheat loss in dense population urban areas.Heat loss by Alternative A can be reduced about 30%compared to that of the present scheme which hasbeen widely adopted in Korea until now. However,Alternative B has more heat loss compared to that ofAlternative A, which was not the common expectation.The main reason was the increase of the pipeinsulation surface area which acts as a heat transferarea. Alternative C and PEX system can bereplaceable when they have merits in the point of initialcost.More enhancements in heat loss can be extracted fromheat loss reduction by the selection of optimum pipediameter, good insulation material, increasinginsulation thickness and changing surface emissivity ofinsulation material.ACKNOWLEDGEMENTThe financial support from KDHC made this workpossible. This paper is based on the results of anongoing research project which will be completed at theend of 2010.REFERENCES[1] W. F. STOEKER, DESIGN OF THERMALSYSTEMS 3rd edition, Mc Graw Hill, pp. 53-160[2] Incropera, HEAT TRANSFER 5th,WILEY[3] Byung-sik Park et al, Study on the Reductionmethod of Heat Loss from the Secondary Pipelinesinstalled in the Apartment Complex, 2008[4] Byung-sik Park et al, Study on the Reductionmethod of Heat Loss from the Secondary Pipelinesinstalled in the Apartment Complex, 2009[5] Flowmaster, Flowmaster heat transfer manual[6] Manfred Kl psch, Plastic pipe system for DH,Handbook for safe and economic application, IEAR&D Programme on District Heating & Cooling111