During the last decade, an increasing interest in Underfloor Air-Conditioning (UFAC) systems has emerged. This is due mainly to an increased demand from employees for a greater control over their working environment. And the building and its engineering systems not only have to be designed to achieve the high standards of environmental control at economical cost, but also thermal comfort is an important factor that influences occupants' satisfaction with the indoor office environment.
Achieving optimized partial improvements of the indoor climate may often be better than to know all optimal levels. The purpose of this study was to investigate the relative importance of temperature, noise, draft and window area. 30 heat-acclimatized subjects participated in 10 exposures in single person climate chambers. Each exposure lasted three hours. During an exposure, the subject was free to optimize the operative temperature at a link to either draft, noise or window area. For each pair of parameters, three linear links were tested.
In summer, it is possible to achieve a satisfactory comfort in residential buildings with purely passive means as thermal inertia, possibility of cross ventilation and solar protection of the external envelope. These parameters have to be taken into account at the earliest stages of building design.
Rating or ranking techniques are often used for checking compliance with regulations, evaluating the efficiency of a retrofit, or even labelling a building. However, the building is, in most cases, rated on very few parameters - when not only one - among many building qualities that should be taken into account. Within the frame of the Joule-Therrnie OFFICE project, a multicriteria ranking methodology, based on the ELECTRE family algorithms, is being developed.
A numerical simulation method is developed for predicting the effective radiation area and the projected area of a human body for any postures. This method is based on the solar heat gain simulation for buildings. To confirm the validity of the present method, predicted effective radiation area factors and projected area factors for both standing and seated person are compared with those by the measurements. It was found that predicted values agree quite well with those by the subjective experiments within 10% accuracy.
Awareness of the need for energy efficient houses has never been so high, but are low energy dwellings delivering the performance they promised, or are comfort levels rising?
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