Study On Optimization Of Insulation Thickness Of Directly Buried Heating Pipes Based On Actual Operation Parameters

In this paper,from the point of view of economy and environment,a mathematical model for optimizing the insulation thickness of double pipes for directly buried heating is established based on the actual operating parameters(Actual operating supply water temperature and Actual operating return water temperature).Through a specific case,the model solution results of economic insulation thickness and environmental insulation thickness of directly buried heating double pipes are analyzed.The specific contents include the following four aspects:(1)The calculation methods of the annual insulation material cost and annual heat loss cost of directly buried heating double pipes are given.Based on the annual total cost,the mathematical model of economic insulation thickness of directly buried heating double pipes is established,and the mathematical model is solved by MATLAB.(2)The Eco-indicator method is introduced,and the calculation method of annual insulation material environmental impact and annual heat loss environmental impact of directly buried heating double pipes is given based on the Eco-indicator method.Based on the annual total environmental impact,the mathematical model of environmental insulation thickness of directly buried heating double pipes is established,and the mathematical model is solved by MATLAB.(3)Taking the directly buried heating double pipes with diameters of DN50,DN100,DN200,DN400,DN600,DN800 and DN1000 in Beijing as a case,the annual insulation material cost,annual heat loss cost and annual total cost of directly buried heating double pipes are calculated.The effects of heat source type,insulation material type,operating strategy and buried depth of pipe on the annual total cost are discussed.The economic insulation thickness and minimum annual total cost of different heat source type,different insulation material type,different operating strategy,different buried depth of pipe and different pipe diameter are analyzed.The results show that the ideal heat source type,insulation material type and operating strategy are coal-fired combined heat and power plant,rigid phenolic foam and quality adjustment,respectively,while the large buried depth of the pipe saves the annual cost.Through the sensitivity analysis,it is found that the unit heating cost and the price of insulation materials are the sensitive factors to be considered in the selection of economic insulation thickness.(4)Taking the directly buried heating double pipes with diameters of DN50,DN100,DN200,DN400,DN600,DN800 and DN1000 in Beijing as a case,the annual insulation material environmental impact,annual heat loss environmental impact and annual total environmental impact are calculated.The effects of heat source type,insulation material type,operating strategy and buried depth of pipe on the annual total environment are discussed.The environmental insulation thickness and minimum annual total environmental impact of different heat source type,different insulation material type,different operating strategy,different buried depth of pipe and different pipe diameter are analyzed.The results show that the most ideal heat source type,insulation material type and operating strategy are coal-fired combined heat and power plant,glass wool and quality adjustment,respectively,and the large buried depth of the pipe is beneficial to the environment.Through the sensitivity analysis,it is found that all the sensitivity factors have great influence on the environmental insulation thickness.