The purpose of this paper is to improve our understanding of the transient behaviour of airing by window opening. While a few simple models exist to analyse the results of window opening, its transient behaviour is not yet well understood, in its effects on air change rates, air temperature and ventilation efficiency. The paper achieves its purpose in the first place by using a synthesis of numerical modelling activity. Then a critical analysis of the methods of calculation is undertaken, comparing both detailed (CFD) analysis results and simplified or zonal models predictions.
Describes an investigation of the possibility of using artificial neural networks to predict air pressure coefficients across openings in a lightweight single-sided naturally ventilated test room. The network was trained using experimental values. A monitoring experiments was carried out on the outside local temperature, wind velocity and direction. Estimates were made of the pressure coefficients at the top and bottom of the openings from the recorded data of air pressures and velocities across the openings with indoor air temperatures.
Describes a global approach to passive design of naturally ventilated buildings situated in the French overseas territories. This approach involves all those involved in the buildings creation process, including architect, owner, building physicists and climate engineers. A validated thermal and airflow building simulation software was used to assess the design and sizing. A reference document was created from the optimal technical specifications, and has been used to build over 800 new pilot homes.
There are important benefits to come from using passive techniques as opposed to artificial cooling. They may not be sufficient to provide thermal comfort throughout the year in wet tropical areas, however. Few experiments have been performed on the thermal performance of buildings using a mixed-running strategy in warm-humid climates. The paper attempts to demonstrate that a possible dual-mode integrated operation can be used for such locations.
Interest in natural ventilation is growing in the USA. Potential benefits include lower energy costs, improved indoor environmental quality and greater occupant satisfaction. Describes the challenges presented by the implementation of natural ventilation strategies.
This study investigates the viability and cost effectiveness of natural ventilation in Istanbul. A typical high-rise office building was used for the investigation together with detailed local weather data including average temperature, wind speed and wind directions for each month of an average year. Data and methods provided by ASHRAE is used to calculate the air pressure at a particular window taking into account wind speed and direction, outside temperature, height and the building's location. The study uses a simple computer program to do this.
Presents CFD simulations and field experiments on ventilation efficiency in an underground car park with natural ventilation. A series of experiments were carried out to validate the results of the CFD calculation, looking at the decay of the concentration of tracer gas (SF6) in the area studied. A long/linear analysis of concentration with time was used to deduce the air change rate. It was found that experimental data were in good agreement with the CFD simulation result.
Natural cooling has an important role in decreasing fuel consumption in buildings. The design is mainly directed at reducing heat gains. The following elements are part of the passive precautions taken: window direction, type of fenestration, window surface areas, outside wall construction, inside thermal mass, thermal insulation, shades, and building configuration. The evaluation of these parameters and of natural cooling's feasibility is done by computer simulation. The article describes a computer program devised for this purpose.
States that natural ventilation systems do not sometimes perform well in conditions of high wind and/or low external temperature. Occupants shut down the system to prevent draughts. In contract, in warm summer weather the lack of air movement is a problem. Hybrid ventilation helps mitigate some of these problems. The paper outlines problems in connection with hybrid systems and indicates solutions for them. Gives examples of hybrid system, some in use and some under construction.
Presents the main features of a preliminary HVAC system project relative to a university complex, based on principles of sustainability. The design involves installation of a cogeneration system. It is proposed to incorporate hybrid and natural ventilation for energy efficiency. Gives examples of architectural designs for the various areas.
Login