Study On Radiant Heat Loss Of The Back Of Heating Radiator

As the terminal device of heating systerm, the heating radiator palys an important role in the whole building energy saving.So,the energy saving of heating systerm has caused high attentions in the region,while radiant heat loss of the back of heating raditior has not caused enough attentions and there are few people who carry out comprehensive research on heat transfer of air gap of radiator back.Especially with the condition that lots of new style radiators emerge in the market and there are not enough research results after the reform of wall structure,the existing theories can not meet the need of building energy saving.So,it is necessary to further theoretical research and analysis on heat transfer according to this air gap structure.From the building equipment energy saving perspective ,this paper unfolds the relevant research work according to the basic heat transfer law of air gap structure and practical problems of engineering application.During the research process,this paper simplies the modle of air gap and analyzes the theory according to several common radiator structure forms in the market.Then,based on theories of radiaton and convective heat transfer and characters of engeering,this paper draws a conclusion of theoretical calculation method of radiant heat loss of heating radiator.Besides,this paper detailed discusses the direction of heat flow of natural convective heat transfer in the air gap.To verify the accuracy of theoretical calculation,this paper has used two ways to detect the heat dissipating capacities of all sorts of heating raditor accoring to the national standards《the calorimetry method of heating radiator》.The first way is to test the total heat dissipating capacites of heating raditor,and the second way is to test the heat dissipating capacities of heating radiator with a thermal insulation board behind it.Then,based on the comparison and analysis of heat dissipation performance in the two ways,this paper calculates the total radiant heat loss of heat rasitor , comes to a conculsion of the change law of radiant heat loss rate under various calculating temperature differences, and makes the comparative analysis of radiant heat loss .To futher explain the distribution of heat flow in the air gap,this paper numerically simulates the distribution of heat flow in the air gap. Finally,this paper detailed calculates the error between experiment and numerical calculation,and analyzes reasons of the error.With the theoretical and experimental analysis ,it is found that the radiation heat loss of heating radiator could not be neglected, and the maximum of loss rate could reach 4.7%.Besides, there are some other factors that can impact results such as material,structure form ,surface coating colour and systerm operating condition.The results of this paper have a guiding significance to the research and development of energy saving radiator,and also have an reference significance to the choice and the comprehensive evaluation of heating radiator in the energy saving buildings.