Research On Thermal Comfort Of Natural Ventilation Office Building In Tianjin

It is numerical simulation, testing and investigation of thermal comfort of natural ventilation office building in Tianjin in transient season. The building locates in city suburbs. It includes external zone, internal zone and atrium. Enclosure of building conforms to Standard of the Third Step Energy Conservation issued by Department of Construction. Considered comprehensively outdoor temperature and solar radiation and indoor cooling load, it is numerical simulated indoor thermal comfort of stack natural ventilation without wind weather and crossing natural ventilation with wind weather. The results of numerical calculation indicate that only by stack natural ventilation, the indoor temperature is linear relative to building cooling load when it is not windy. When it is windy, pressure field of building outward surface is calculated firstly under prevalent wind direction and mean air velocity, and then based on boundary condition of pressure openings, calculates indoor air velocity, temperature and pressure fields and presents the linear relationship between indoor temperature and building cooling load. From Apr. 13th to Apr. 17th in 2009, indoor temperature, relative humidity and CO2 density are tested. Tested result shows that indoor temperature and CO2 density meet with adaptive thermal comfort model and ASHRAE Standard of natural ventilation building, but relative humidity can not meet with the lowest limit of thermal comfort because of local climate feature. The relationship between tested indoor temperature and building cooling load are similar to theory calculation result, and they are different numerically. This is resulted by differential in open degree of openings and lighting cooling load in reality and theory. During testing period, investigation questionnaires are filled by people working in the building. Statistic result reveals that 94.37% people like ventilation environment compared with air conditioning environment, indoor thermal environment is satisfied by 96.25% people, and indoor air quality is 94.17%. There is not obvious discomfort about low relative humidity because of long-term living accustom. In transient season, outdoor temperature changes acutely, people open or close doors and windows to adjust indoor temperature according to thermal sensation, and put on or put off clothes to adapt themselves to indoor thermal environment. Therefore, thermal comfort evaluation in transient season should be based on indoor temperature.