Evaluation And Optimization Of Thermal Environment Of Platform In Open Space Under AC System In Dry And Hot Climate

Along with the exaltation of the living standard, the demand for thermal comfort has increased parallelly. People all around world try to create more comfortable thermal environment. At this moment the common used international standards are ASHRAE standard and ISO 7730 standard. In particular the public space has considered of the thermal comfort since the beginning, going though whole process including the design, construction and operation, in purpose to make it more acceptable for more occupancy. Furthermore people from different areas are used to adopt local special equipment and method to improve the thermal environment.From June 2013 to end of September 2013, with the measurement record and questionnaire for thermal comfort this article tries to indicate the thermal environment of the platform without envelope in open space. The questionnaire combines the local basic parameters and the subjective feelings and the analysis is found on the base of objective measurement. The analysis and prediction of thermal environment on platform which follow the standard of ISO7730 and ASHRAE 55-2004cost four months, June, July, August and September. It is the typical hot desert climate which is proofed by Mecca weather history of 2013.895 questionnaires are done in these four months. From the analysis we can find it clearly that the results of local passagers and Chinese stuff have great difference and we try to explain the difference from physical aspect, psychology aspect and behavior aspect. On the base of local passengers questionares we establish a adaptive model for platform thermal environment Tn= 0.345 Tout+18.44,out door temperature is from 32 to 42℃.For the Chinese stuff we have a brief description of the three factors for local discomfort.Due to the dissatisfaction of the thermal environment simulation is used to improve the percentage satisfaction. The main area from platform is devided to "departure area" and the focus of the improvement of thermal environment is for this area. The fuction formular Tave=f(loc, V, t) means the key factor,average operative temperature, of departure area has three variables which are location of air supply, velocity and temperature of air supply. The average temperature of departure area is expected by simulation in different case of these three variables. The comparation of average temperature of departure area and neutral temperature is the critical reference to the ways of improvements. It is found that on the condition of 1 metre parallel movement to left side the air supply should follow the range of 26℃<Ts<30℃,2.4 m/s<Vs<3.2 m/s to guarantee the PPD is under 10%.