Human Thermal Comfort In Free Running Minimum Building Under Summer Condition

With the advancement of China's modernization process,China's economic level,people's living standards and energy protection awareness have been significantly improved.In recent years,luxury pursuit of building scale has greatly affected the earth's ecological environment.The heavy and dense constructions have almost overwhelmed the earth.Thus accordingly,people started taking action to decompress the earth.In this case,the design idea of "extreme miniaturization" of buildings is gradually recognized and commended by some architects.The "minimum building" studied in this paper is different from the small-sized building in the usual sense.Under the premise of a small area,such buildings adopt a nonlinear design method,which makes it possible to have a personalized indoor space.In this paper,the combination of on-site questionnaire,experimental test and numerical simulation is used to research and explore the human thermal comfort problem in the free running small building under summer conditions,and propose some improvement measures of human thermal discomfort.The experiment was carried out in a very small building model built by our group,and the experimental data was processed and analyzed by statistical analysis software Oringin.As we know,when it is in hot-summer and cold-winter zone,even if the house has certain ventilation measures,there are still many people who feel hot and have a negativesenssation on the comfort of the human bodyin the non-air-conditioned environment of free running small buildings.The research results show that the main factors affectingindoor thermal environment and human thermal comfort include outdoor meteorological parameters,enclosure structure characteristics,human activity intensity and many other factors.For the thermal sensation voting indicator TSV,the thermal sensation of clear day is the hottest,the cloudy day is second,and the rainy day is basically not hot,orto some extent are slightly cooler.For the thermal comfort voting indicator TCV,the rainy day is between comfortable and slightly uncomfortable,and is the most comfortable situation in above three weather conditions,meanwhile,the discomfort of clear day and cloudy day is relatively strong.The TSV and TCV are positively correlated with the activity intensity in summer,and the values of them increase with the increase of the activity intensity.This is mainly because the body's calorific value increases along with the intensity of human activity increases,,which increases the body's thermal discomfort.Refer to the real minimum construction,a numerical model was built.Through the simulation of indoor temperature,humidity,air velocity,PMV and PPD,it was found that,people are basically comfortable under the summer rainy conditions,but it is difficult to achieve comfort under typical clear day only by relying on natural ventilation,so improvement measures are needed.In this paper,three improvement measures are proposed,which are to increase the thickness of the wall insulation layer,change the window-to-wall ratio,and enhance the draughts under the condition that the window-to-wall ratio is 0.4.Under the condition of increasing the insulation layer,the indoor average temperature is about 2.0? lower than the typical working condition,the air flow rate changes little,the relative humidity increases,and the PMV value and PPD value also decrease slightly.Under the condition of changing the ratio of window to wall,the effect of window-to-wall ratio is 0.4,the temperature of the whole minimum building can be lower than the temperature under typical working conditions by about 2.6?,and the decrease of PMV value and PPD value is comparative obvious.Under the condition of forming draughts,the indoor air flows are very smooth,the air age is small,and people has obvious blowing feeling,which leads to the enhancement of the evaporate heat of human surface,and the PMV value and the PPD value are significantly reduced.The purpose of this paper is to obtain the experimental and simulation results of the indoor thermal environment and human thermal comfort parameters of the minimum construction under summer conditions,and propose some improvement measures.The results willgive theoretical principle and data support for further research on the indoor thermal environment and human thermal comfort inminimum buildings,and provide reference value for the application and promotion of such buildings.