ABSTRACT
While thermal comfort in mass transportation vehicles is relevant to service quality and energy consumption, benchmarks for such comfort that reflect the thermal adaptations of passengers are currently lacking. This study reports a field experiment involving simultaneous physical measurements and a questionnaire survey, collecting data from 2,129 respondents, that evaluated thermal comfort in short- and long-haul buses and trains. Experimental results indicate that high air temperature, strong solar radiation, and low air movement explain why passengers feel thermally uncomfortable. The overall insulation of clothing worn by passengers and thermal adaptive behaviour in vehicles differ from those in their living and working spaces. Passengers in short-haul vehicles habitually adjust the air outlets to increase thermal comfort, while passengers in long-haul vehicles prefer to draw the drapes to reduce discomfort from extended exposure to solar radiation. The neutral temperatures for short- and long-haul vehicles are 26.2 degrees C and 27.4 degrees C, while the comfort zones are 22.4-28.9 degrees C and 22.4-30.1 degrees C, respectively. The results of this study provide a valuable reference for practitioners involved in determining the adequate control and management of in-vehicle thermal environments, as well as facilitating design of buses and trains, ultimately contributing to efforts to achieve a balance between the thermal comfort satisfaction of passengers and energy conserving measures for air-conditioning in mass transportation vehicles.
Subject(s)
Acclimatization/physiology , Air Conditioning , Motor Vehicles , Thermosensing/physiology , Air , Air Conditioning/standards , Air Movements , Clothing , Conservation of Energy Resources , Consumer Behavior , Humans , Humidity , Motor Vehicles/classification , Surveys and Questionnaires , Taiwan , Temperature , Time FactorsABSTRACT
As urbanization expands and diversifies, weather data produced by a single weather station in a suburb are no longer adequate to represent and reflect microclimatic changes of a city. This study selected 34 automatic weather stations in Tainan City, Taiwan, to conduct temperature and humidity measurements over a period of one year. Based on those observed weather data and urban environment parameters obtained from a geographic information system, as well as morphing approach, this study constructed a method of generating hourly local weather data for urban areas while accounting for urban heat island (UHI) effect in summer. Meanwhile, we discussed the relativities of the urban form and its structure against the variations of local hourly temperature and relative humidity under six buffer scenarios. Error analysis results revealed that minimal prediction errors can be obtained using the buffer scenario involving a 1000â¯×â¯1000â¯m2 four-layer buffer with inner and outer layers and upwind and downwind areas. Finally, using the hourly weather data produced for Tainan City, we calculated the long-term cumulative UHI intensity (UHII) and urban bioclimatic indexes (i.e., thermal stress, use of natural ventilation, and cooling degree day) and investigated how urban form and structure are related to UHII, thermal stress, use of natural ventilation, and cooling degree day. The results can inform urban policy making.
ABSTRACT
The outdoor thermal environment is expected to be deteriorated under climate change. An approach of risk identification including assessment from aspects of thermal stress effect, people's exposure, and local's vulnerability were adopted to study a hot-and-humid traditional rural community located at Tainan, Taiwan. Layers of each aspect were either constructed by in-situ measurements or simulations. To evaluate the future thermal comfort changes by simulations, the prerequisite hourly climate data of three future time slices were produced. Prognostic simulation model, ENVI-met, in combination with diagnostic model, RayMan, were respectively used for identifying current spatial distribution of thermal stress and for assessing the future thermal comfort changes. High thermal risk area was identified by superimposing layers of hazard, exposure and vulnerability. It revealed that because of the tourists' vulnerability to adapt local climate and the inflexibleness of choosing visiting time, it exhibited a high thermal stress at the Main Courtyard where its thermal comfort conditions will be deteriorated due to climate change. Furthermore, the thermal comfort conditions in various shading orientation were analyzed based on the changing climate in three future time slices, i.e. 2011-2040, 2041-2070, and 2071-2100. The results show the area with shading in the East and West side is more comfort than in the North side. In hot season, shading in the West side contributes less PET increasing, especially in the afternoon period. The severest overheat problem (the physiological equivalent temperature, PET>40°C) at the Main Courtyard will increase from current 10% to 28% in 2071-2100 in terms of overheating occurrence frequency. The results of this study can be used as the guidelines for environment analysis before planning or redesign community.