Development Of Portable Wall Thermal Resistance Test System And Relevant Influence Factors Analyses

With the momentum of global industrialization, all kinds of environmental problems havebegun to emerge endlessly, energy conservation and emissions reduction also have become theconsensus of all countries in the world. Within the energy consumption, building energyconsumption in developed countries occupies about a third of its total energy consumption. Andfor our country,21%~24%of all the commercial energy utilization belong to building energyconsumption, and the percentage will continue to increase with the development of socialeconomy. So the enforcement measures of energy conservation and emissions reduction is theinevitable requirement if we want a more healthy social development.Because of the large energy saving potential,building energy conservation is the foremost,rate of the heat transfer of the building envelope occupy a large part of building energyconsumption including heating of air conditioning, the heat transfer coefficient of the enclosurestructure is strictly limited in the new design standard of building energy conservation, but thetesting of wall thermal resistance in the laboratory can’t reflect the actual heat transferperformance, and the existing thermal resistance test methods in-situ have differentrestricted conditions. Therefore it’s particularly important to develop a portable and moreadaptable equipment to detect the thermal resistance of the envelopes.Comparisons between the test method of adiabatic structure in the laboratory and the testmethod for wall thermal resistance in-situ were analyzed in the article. Also the application of dataanalysis methods is introduced in this paper. Based on the existing in-situ measurement methodsof envelope’s thermal resistance, a new type of portable measurement method of buildingenvelope’s thermal resistance is put forward.From the point of construction of this new test system, the compositions of the new testsystem and data processing methods are introduced, In order to explore the relationship betweenthermal resistance and the selection of heating area, a series of field test experiments were carried on.With the comparison of ANSYS models and field measurement results,the feasibility of thesimulation is verified.A new judgment standard of the quasi-steady state and the needed testing time are proposedduring the analysis of the data processing, then the relevant influence factors and solutions are putforward.The principle and influence factors of heat flow meter are mainly introduced. The calibrationof the heat flow meter and output signal processing modification, also the wall heat capacity factorcalculation analysis are further included. In particular, further study about the stability of thesignal output of heat flow meter is carried on, then the correctly used methods and influencefactors of heat flow meter are put forwarded.On the basis of experiments and numerical simulation analysis, the portable wall thermalresistance test instrument is fabricated. The new fabricated instruments and conventional testmethod were applied to field test experiment at the same time. Compared the test results with thetheoretical thermal resistance value and the superiority and limitations of this new kind of portablewall thermal resistance test instrument were put forward. Also the application environment andimprovement methods are mentioned in in the article.Based on the simulation analysis and experimental verification, the fitting function about thetest error caused by the lateral heat loss rate and dimensionless parameter D/d (the ratio of heatingside length-D and the wall thickness-d) is concluded. Finally in the topic outlook, a new idea byusing two pieces of heat flow meters to reduce the heating area and the size of testing instrumentsis proposed.Finally, research projects about the portable Wall Thermal Resistance Test System and theweakness of the new test method and problems needed to be solved were summarized and thesubject task is prospected.