Abstract: This study aims to determine the optimal approach for evaluating thermal comfort in an office that uses natural ventilation as the main conditioning strategy; the office is located in Quito-Ecuador. The performance of the adaptive model included in CEN Standard EN15251 and the traditional PMV model are compared with reports of thermal environment satisfaction surveys presented simultaneously to all occupants of the office to determine which of the two comfort models is most suitable to evaluate the thermal environment. The results indicate that office occupants have developed some degree of adaptation to the climatic conditions of the city where the office is located (which only demands heating operation), and tend to accept and even prefer lower operative temperatures than those considered optimum by applying the PMV model. This is an indication that occupants of naturally conditioned buildings are usually able to match their comfort temperature to their normal environment. Therefore, the application of the adaptive model included in CEN Standard EN15251 seems like the optimal approach for evaluating thermal comfort in naturally conditioned buildings, because it takes into consideration the adaptive principle that indicates that if a change occurs such as to produce discomfort, people tend to react in ways which restore their comfort.
Abstract: Daylight can be considered as one of the most important principles of sustainable architecture. It is unfortunate that this is neglected by designers in Tehran, a city that benefits from a significant amount of daylight and many clear sunny days during the year. Using a daylight controller system increases space natural light quality and decreases building lighting consumption by 60%. It also affects building thermal behavior, because most of them operate as shading. The light shelf is one of the passive systems for controlling daylight, mostly used with shading and installed in the upper half of the windows above eye level. The influence of light shelf parameters, such as its dimensions, shelf rotation angle and orientation on daylight efficiency and visual comfort in educational spaces is investigated in this article. Daylight simulation software and annual analysis based on climate information during space occupation hours were used. The results show that light shelf dimensions, as well as different orientations, especially in southern part, are influential in the distribution of natural light and visual comfort. At the southern orientation, increased light shelf dimensions result in an increase of the area of the work plane with suitable daylight levels by 2%–40% and a significant decrease in disturbing and intolerable glare hours.
Abstract: The unique architectural style of traditional “Yinzi” dwellings in Western Hunan, China, needs to be protected and their natural ventilation of patio space should also be promoted. Therefore, this study aimed at finding out the natural ventilation values and limitations of “Yinzi” dwellings as well as designing an optimum ventilation strategy for such dwellings. In this work, the thermal environment of a typical “Yinzi” dwelling was tested. The two patios and living room space of “Yinzi” dwellings was selected for a quantitative analysis, and CFD software was adopted to simulate the stack effect of different patio proportions under the same static wind environment conditions. In addition, an orthogonal experiment is combined with CFD simulation to explore the best proportion and position of patio of “Yinzi” dwellings. A final optimum ventilation strategy is provided for the “Yinzi” dwellings, which can significantly promote the natural stack effect of “Yinzi” dwellings in summer.
Abstract: The building constructions investigated in this work are pitched wooden roofs with exterior vertical drainpipes and wooden load-bearing system. The aim of this research is to further investigate the building defects of pitched wooden roofs and obtain an overview of typical roof defects. The work involves an analysis of the building defect archive from the research institute SINTEF Building and Infrastructure. The findings from the SINTEF archive show that moisture is a dominant exposure factor, especially in roof constructions. In pitched wooden roofs, more than half of the defects are caused by deficiencies in design, materials, or workmanship, where these deficiencies allow moisture from precipitation or indoor moisture into the structure. Hence, it is important to increase the focus on robust and durable solutions to avoid defects both from exterior and interior moisture sources in pitched wooden roofs. Proper design of interior ventilation and vapour retarders seem to be the main ways to control entry from interior moisture sources into attic and roof spaces.
Abstract: This research investigates the overall heating energy consumptions using various control strategies, secondary heat emitters, and primary plant for a building. Previous research has successfully demonstrated that a dynamic distributed heat emitter model embedded within a simplified third-order lumped parameter building model is capable of achieving improved results when compared to other commercially available modelling tools. With the enhanced ability to capture transient effects of emitter thermal capacity, this research studies the influence of control strategies and primary plant configurations on the rate of energy consumption of a heating system. Four alternative control strategies are investigated: zone feedback; weather-compensated; a combination of both of these methods; and thermostatic control. The plant alternative configurations consist of conventional boilers, biomass boilers, and heat pumps supporting radiator heating and underfloor heating. The performance of the model is tested on a primary school building and can be applied to any residential or commercial building with a heating system. Results show that the new methods reported offer greater detail and rigor in the conduct of building energy modelling.
Abstract: Due to increasing pressure to reduce the energy demand in buildings, thermochromic thin film based glazing has become a recognized potential solution due to the intrinsic ability to modulate the solar heat gain of a window as a function of the materials temperature. These “intelligent” glazings have been investigated for several years, and it has been found that, through variation of synthetic route, the thermochromic properties (transition temperature, hysteresis gradient and width) can be altered; however, less attention has been applied to how such alterations affect the overall energy savings attributed to the materials. In this study the building simulation software EnergyPlus TM has been used to model a series of idealized thermochromic spectra in a series of different environments to evaluate their energy saving potential against both clear glass systems and industry standards. The idealized spectra are used to see what effect each of the materials thermochromic properties and therefore elucidate which are the most important with respect to the energy saving properties. It was found that the best thermochromic materials were those with a narrow sharp hysteresis and a low transition temperature and result in an increase in energy saving between 30%–45% across the different environments compared to clear glass systems.