thermal environment

People spend 70% -90% of their time indoors. Indoor air quality and human body’s health have a close relationship. With the advance of society, user comfort requirements for thermal environment are rising. Humidity is an important parameter for evaluating indoor air quality, which not only affects the thermal comfort of the human body but also seriously restricts the function of the building. In winter, the indoor humidity is dry. When using humidifier, the humidity around the humidifier is higher, but there is still a dry area in the room.

Flow interaction between thermal plumes and vertical air distribution and the resulting airflow structures were investigated under increasing heat load conditions. The main objective was to investigate the large-scale flow patterns, airflow fluctuation and frequency of the flow field. The flow interaction between thermal plumes and ventilation provides random flow motion and vortical structures that further effect the airflow characteristics such as velocity and temperature fields, turbulence intensity and frequency of the fluctuations.

This study aims to assess the thermal conditions of an indoor environment deemed unacceptable by workers. For this purpose, Ostracon, a voting device, was developed to record the physical environment at the time a worker presses a button to express a complaint. Ostracon was used to record the opinions of 90 workers about their thermal environment in six offices during the summer. The results show that workers found the indoor thermal environment unacceptable even when the static thermal conditions were within a range that was predicted to be comfortable.

The purpose of this study is to develop a thermal design tool for architectural designer by combining a heat balance simulation for urban surfaces, including buildings, the ground and greenery, with a 3D-CAD. This tool is constructed by improving the previous simulation model, which uses the Geographic Information System for the input data. The simulation algorithm is improved so as to predict the surface temperature distribution of urban blocks while taking into account the actual design of the outdoor space using the 3D-CAD system.

In order to make sustainable single houses, it is very important to control the outdoor thermal environment. Therefore, various relaxation methods for the outdoor thermal environment are often planned, e.g. utilizing of the cooling effect of a water face, arrangement of water permeable material, planting trees etc. In this paper, a coupled simulation of CFD and radiation transfer is conducted in order to evaluate the outdoor thermal environment in riverside detached single houses near to Tokyo in Japan.

Here a generalized 3-D radiation simulation system is developed with Monte-Carlo and Gebhart method. There are two kinds of basic units in the system, which are surface unit for opaque objects and body unit for transparent objects respectively. When the bundles were emitted from certain point or surface with Monte-Carlo method, it would enter into an opaque surface or a transparent body. For the former, it would be reflected and absorbed. However, when the second situation happened, there is the third process named penetration beside above two processes.

Variable Refrigerant Volume(VRV) air-conditioning system is more liable to meet thermal environment problem than other systems such as split-type air-or window-type air-conditioner because its capacity of outdoor unit is much higher. When used in high-rise building, hot air dissipated by the outdoor units will induce buoyant airflow and increase the working temperature of units at high floor when these heat can not be dispersed in time. High working temperature could not only degrade the total efficiency, but also cause stoppage of the system.

The systematic numerical simulation program is developed to calculate the total energy efficiency of housing polymer electrolyte fuel cell co-generation system (PEFC-CGS) which is combined with hot water floor heating (HWFH). This simulation program can also predict actual building physics of heat transfer such as mutual radiant heat among interior surfaces and thermal strage relating with piping pitch of hot water and so on. The indoor temperature can be controlled by PMV (Predicted Mean Vote) to take account of thermal sensing affected radiant heat.

The air barrier technique is to apply the special airflow through window fan to improve the thermal environment near the windows in winter and summer, and especially in winter, to simplify the air conditioning system of perimeter zone of office building and avoid condensation on the surface of window. By using numerical simulation, the paper analyzed the thermal environment of the office building, both applied the air barrier technique or not. The paper also compared the two different methods in winter and summer respectably.

Heat island is a big issue for large cities especially located in hot and moist climate in Asian countries. The phenomenon is severer in an urban canyon because of surrounding highrise buildings causing little ventilation and heat dissipation from traffic. The first purpose of this study is to investigate thermal environment of a main street in Osaka by intensive  measurement in the summer of 2006. Osaka is the second largest city and suffers from the most severe heat island in Japan.