The principles of a new tracer gas technique is described in the paper. The new technique involves pulse injection of tracer gas and has the same advantages as the previously known homogeneous emission technique. It can for example advantageously be used in large buildings and buildings with many rooms and yields information on the distribution of ventilation air within the building. However, contrary to the homogeneous emission technique, yielding the average ventilation performance during an extended time, the new technique allows measurement during short term periods.
Concentration of pollutants produced by car traffic in a street below the roof level has large spatial variations. In a street, pollutants are diluted by the turbulent air flow which is induced by the wind speed above the roof level, and also produced by car displacement. The airflow structure is in relation with street size and building shape. Particularly strong gradients of concentrations can be observed vertically and also horizontally in front and along buildings where are set up ventilation inlets and windows.
Natural ventilation in office buildings can sometimes offer other advantages than traditionalmechanical ventilation systems. Often natural ventilation systems are promoted at an earlystage by an architect, but perceived dificulties, e.g. to pre-determine the function of a naturalventilation system, can serve as a barrier and a mechanical system is often chosen instead.
This paper reports on the findings of a research exercise that has aimed to crystallise the current state of the Indoor Air Quality debate across a broad spectrum of the industry. The findings are discussed and conclusions drawn on whether there is evidence that the industry's efforts towards delivering good Indoor Air Quality is well received by building owners and operators in appreciable numbers
The goal of this work is to better understand the influence of window U-factor and solar heat gain coefficient on residential space heating and cooling energy use in the United States. We calibrated our simulation models with residential energy use data and evaluated the affect of window U-factor and solar heat gain coefficient on space heating and cooling energy use. U-factor and solar heat gain coefficient have a comparable impact on heating energy use, whereas U-factor has a minor impact and solar heat gain coefficient has a strong impact on cooling energy use.
CO2-based demand-controlled ventilation (DCV), when properly applied in spaces where occupancies vary below design occupancy, can reduce unnecessary over ventilation while implementing target per-person ventilation rates.
This paper describes the development of software for simulating the air-conditioning environment in a computer room. This software uses a finite volume method combined with a rectangular structured mesh system and a k-£ two-equation model for turbulence. Some special modeling techniques are also used. This software has two purposes: (1) to optimize the layout of a computer room, thus minimizing the electric power used for air conditioning, and (2) to reproduce the situation in which an accident is caused by an air-conditioning problem and to assist in an investigation of the problem.
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