Bulk Moisture Porous Material Equivalent Thermal Parameters Experimental Methods And Uncertainty

The material evaporate its accumulation of moisture is a common natural phenomenon. The use of evaporative water to cool the building envelope now is more and more concerned by people as a passive building technology. This technology enables the use of natural resources, repeat the cycle, effectively reduce energy consumption and helped improve the urban thermal environment, more in line with today’s social context of energy shortage and sustainable development.Thermal parameters of materials are used to evaluate the thermal performance of the material in the heat transfer process. The current material specification thermal parameters involved were obtained under steady state conditions. However, in reality, the material can not be under steady state conditions, and materials stored water due to the presence of water is a greater impact on its thermal performance. Equivalent thermal parameters reflect the material under certain circumstances at this time is more representative of the material thermal performance parameters.It’s great significance to the theory of passive evaporative cooling. But there is no equivalent of the thermal storage material parameters for accurate metering program, and has no study of its measurement uncertainty.Aiming at the above problem by experimental measurement instruments hot and wet climate wind tunnel experiment station has been involved in the measurement qualified metering metrology institute, For those instruments temporarily unable to provide metered by means of a metering mechanism bench has qualified metering calibration method using the relevant specifications provided in the calibration laboratory tests to ensure that all those involved in the instrument accuracy. Meanwhile, the experimental program are not required placement test specimen some testing to determine the specific location, so the experiment can be carried out smoothly. The evaluation results of equivalent thermal parameters were the case then the wind tunnel experiments, to obtain a series of porous material moisture phenomenon of heat and moisture conditions under typical meteorological day to calculate equivalent thermal parameters of the specimen, and the experiment was repeated five times in the operation uncertainty. The main results of this paper are:1)By selecting protective chamber 3 measuring points, analysis and comparison of the environment in which each measuring point, at room temperature to determine the placement of the sink and drain rack. In the air-conditioned chamber weighed down each partition layout three measuring points, analysis and comparison of each measuring point temperature variation, the best placed to determine the location of small air-conditioned room temperature measuring point.2)With CMA measurement certification have flat plate heat flow meter thermal conductivity instrument to be calibrated to obtain a stable experimental method of plate heat flow meter calibration, and got a plate heat flow meter sensitivity.3)Wind tunnel experiments, obtained permeable brick under aqueous conditions, the quality of the specimen, the specimen temperature inside and outside surfaces of the inner and outer surface heat flux variation with time.4)Calculated the hourly rate of evaporation permeable brick under aqueous conditions, the equivalent resistance, equivalent heat transfer coefficient, the equivalent heat storage coefficient. By studying the results of these equivalent thermal parameters combined standard uncertainty of the formula and calculate the uncertainty.