7.2
Applications of a Human Thermal Comfort Model
Gordon M. Heisler, USDA Forest Services, Syracuse, NY; and Y. Wang
We used the COMFA model of Brown and Gillespie (Microclimatic Landscape Design, John Wiley, 1995) as the basis for a Windows® program (OUTCOMES, OUTdoor COMfort Expert System) that aids in evaluating individual tree and urban influences on human thermal comfort and in designing for comfort. OUTCOMES was designed with the goal of providing an easily used interface and ample on-screen help. The program produces an index of comfort for a person based on an energy budget calculation derived from solar radiation inputs, air temperature, humidity, wind speed, reflectivity of the ground and nearby objects, sky view, clothing, and activity. To include tree influences on solar radiation, a graphical tool that shows an elevation (side) view of a tree and a plan (top) view of the tree crown outline and its shadow allows the user to determine whether a person would be shaded at a designated time. A drop-down menu allows selection of the city, from which the program derives latitude and longitude for calculation of solar geometry and solar irradiance. Users can choose from among 46 tree species with representative crown transmissivities in estimating the amount of solar radiation on a shaded person. OUTCOMES output includes the comfort index, a histogram showing the percentage of people expected to be in five comfort categories, and the energy budget components. The budget components are useful for educational purposes. The program may be run in a mode that suggests different tree species for shade if the person’s energy budget is not within comfortable limits. In OUTCOMES, users enter weather data and run the program for one design date and time with each run. Another program developed in conjunction with OUTCOMES uses the COMFA algorithms, but accepts Typical Meteorological Year (TMY) data to calculate in one run the human energy budget for one site for many hours of typical weather data, even for all the hours in a year.
Session 7, Urban biometeorology
Tuesday, 21 May 2002, 2:15 PM-4:28 PM
Previous paper Next paper