A methodology is presented for determining the air flow rate through a stack-ventilated single-spacedenclosure bearing a roof-mounted ventilation tower. We develop a "system discharge coefficient" which takes into account the pressure losses that occur at the intake opening of the enclosure, inside the tower and at the outlet opening. The system discharge coefficient is interpreted as a reduction in the area of the path that the air flow takes. Based on this reduced area the air flow rate is then determined.
In the practical applications, roofs of buildings can be in different shapes depending onarchitectural design of building or climate. Some of these building roofs can be classified asgambrel, saltbox and gable roofs. In the present study, we investigated the natural convectionheat transfer and fluid flow inside the gambrel, gable and saltbox roofs for winter boundaryconditions. With this aim, the identified roofs are compared with each other from the heattransfer and flow field point of view.
Actually and in the near future, due to the necessity of refrigeration, the need of thermal energy dissipation systems will be increased. One of the best element, is the cooling tower, but it has one mean inconvenient, what is the use of a fan. The use of the fan has the following misfortunes: waste of energy, noise, vibration and dissemination of Legionella, if it is present.
Measurements were operated during years 2000 and 2001 on a full-scale test house on the site of BBRI (Belgium) in order to determine the pressures due to the wind on the roof. This paper presents the measurements results and the pressure coefficients obtained. Results are compared with the values of pressures on the roof given by the calculation method of Eurocode 1 (EC1).
This paper presents an approach to evaluate the sensitivity of a roof design to condensation problems, given the uncertainty to achieve continuity of airtightness in practice. The approach consists of a repeated number of simulations with a 2D heat, air and vapour transfer model to predict the variation in roof moisture performance due to various discontinuities in roof geometry. The set of discontinuities is calibrated by comparing measuring data of roof airtightness to simulation results.
Evaluates by measurement and computational fluid dynamic (CFD) modelling, the thermal performance of an atrium integrated with photovoltaic (PV) modules, situated at the Jubilee Campus of the UK University of Nottingham. The project monitored the internal and external environments of the atrium, and applied CFD to the prediction of its thermal performance. Investigated the effect of ventilation strategies on the performance of PV arrays. Found that CFD modelling showed that for effective cooling of roof mounted PV arrays, the air inlet should be situated close to the roof.
Building-integrated photovoltaic (PV) systems are increasingly common in developed countries and have the potential to contribute significantly to electricity generation as a benign alternative to fossil fuel generation. The University of Nottingham has recently completed a new campus, The Jubilee Campus. PVs are integrated into the roofs of four atria for the teaching buildings in the new campus. This paper presents the performance of roof-integrated PVs using CFD (computational fluid dynamics).
A study obtained steady-state solutions for Rayleigh number on flow structure of buoyant flow in a roof of triangular cross-section. The heat transfer was also investigated. It was found that height-base ratio and Rayleigh number have a significant influence on the temperature and flow field.