Research On Strategy For District Heating Regulation

In traditional district heating system, users don’t have self-regulatingpermissions and the main regulating method is changing flow mass at differentstages. With the developing of metering heating systems, the regulating methodwill be variable flow. Thus, the problems about choosing heating parameters andvariable flow need to be researched.The text gives functions of energy consumption with parameters of supplywater temperature and flow. It gives the optimal heating parameters of wholeheating season by three different control strategies. Furthermore, the text gives theparameters that minimum the operation fees by calculating the function.The minimum flow decides the operation consumption of pumps. The textanalyzes the choosing rules of minimum flow by considering all influencingfactors. The text gives the feedforward-feedback methods by analyzing thecharacteristics of metering heating users. The text also suggests regulating ofdistrict heating on constant resistance section in variable flow stage. Furthermore,the text researches the influence of load fluctuation and different resistancesections.Then, the text analyzes the flow-heat properties of plate heat exchanger basedon heat transfer coefficient formula in variable flow conditions. Together with theexisting theory of control valve, the text gives the heat properties of control valve.Furthermore, it also researches on the influence when conditions changes. It givesan assumption that use pressure-temperature cascade control instead ofself-operated differential pressure controlling valves which used in VAV terminalbox.At last, the text develops a specific operational method of an existing districtheating system according to the former theories. Also, it gives the pumpconsumption of different control method by simple calculation.