Energy Utilization Analysis Of Central Heating System Of Tianjin Economic-technological Development Area

In general, central heating system is composed of heat source, heat transmissionpipeline network and heat users. When doing the research of building energyefficiency in our country, due to the lack of comprehensive consideration of heatingsystem, we ignored the energy-saving of the boiler room and the pipeline net,resulting in that coal consumption for heating for energy saving building remains high,namely " energy-saving buildings are not energy efficient ".Taking central heating system of Tianjin Economic-Technological DevelopmentArea as the research object, with the key research of heating source and pipelinenetwork, through establishing the energy equilibrium analysis model and the exergyanalysis model of heating system, the paper does the further research and analysis ofthe energy utilization of the main links and the key energy-consuming equipments.The main conclusions are obtained as follows:(1) The energy efficiency of the western central heating water and steam systemof Tianjin Economic-Technological Development Area are56.34%and42.12%,andthe exergy efficiency are respectively14.51%and15.55%; The energy efficiency ofthe eastern central heating water and steam system are93.78%and93.99%,and theexergy efficiency are respectively94.18%and76.30%.(2) Taking distributions of energy loss and exerge loss into account, the energyloss of the heating source boiler room is between30%~35%, the exerge loss is up to80%, therefore, the boiler room has great energy-saving and exergy-saving potential.(3) The exergy loss of heat pipe network is about5%, but its energy loss is higher,the energy loss of eastern heat pipe network is close to6%; while the energy loss ofthe western hot water pipe network is13%, the energy loss of steam heating networkis as high as22.69%. Therefore, it is very necessary to take measures to the heattransmission pipe network,in order to reduce the heat loss of transmission.(4) The comprehensive energy consumption index of the western central heatingsystem per unit heat production is34.18kgce/GJ, below the limit value of51.08kgce/GJ, which is specified by" Technical specification for safe operation ofheating system in city (CJJ88-2000T)". The comprehensive energy consumptionindex per unit heating area is14.2kgce/㎡, close to the limit value of13.52kgce/㎡,which is ruled by the second step of building energy-saving in Tianjin, but muchhigher than that of9.82kgce/㎡,which is ruled by the third step of building energy-saving in Tianjin. The comprehensive energy consumption index per unitoutput is6.152tce per Rmb10000, which is higher than the national average level0.586tce and the Tianjin average level2.404tce.(5) Thermal efficiencies of the three boilers of west station by testing were69.50%,74.69%and73.79%,which are not consistent with the above78%, specifiedby" monitoring and testing for energy saving of coal fired industrial boilers(GB/T15317-2009)". The measured efficiency of the east and west water pipeline arerespectively84.49%and46.17%, and that of steam pipeline are respectively70.77%and39.97%,which are all lower than the standard value of90%, specified by "Standard for energy efficiency inspection of heating residential buildings(JGJ132-2001)".Through energy utilization analysis of central heating system of TianjinEconomic-Technological Development Area, combined with some of test results, thepaper finds the existed problems, puts forward corresponding measures forenergy-saving reconstruction, and analyzes the energy saving potential.