Difference between the Measured and Theoretical Value and Theirs Influencing Factors for Heat Transfer Coefficient of Exterior Wall External Insulation

This paper analyzed the actual heat transfer coefficient of exterior wall external insulation, which was detected by temperature controlled hot box-heat flow meter method in Nanjing from March to December, 2010 .Research showed that: impacted by one-dimensional stability heat transfer assumption ,78.27% of test values of the heat transfer coefficient for exterior wall external insulation , are less than the calculated values; under certain circumstance, that the external thermal insulation material(Expandable polystyrene shutter, EPS board for short, and Extruded polystyrene shutter, XPS board for short)are the same, the more stable the wall substrate density and material , the greater the heat storage coefficient is and the smaller the relative detection error will be. When using the same stable wall substrate material, the calculation error of XPS board was significantly better than EPS board’s. The analysis, which is about error influence factors of test value of the heat transfer coefficient of exterior wall external insulation, shows that current temperature controlled hot box-heat flow meter heat transfer coefficient method needs further improved and perfect in order to improve the reliability of its conclusion.