We report on four new full scale experiments that were designed to measure the influence of wind on the ventilation and/or heat loss rates through single large openings: a) test-house with horizontal slit opening, set-up to measure internal pressures and the effect of air-compressibility (CSTB, France), b) attic with window ajar, set-up to measure long term ventilation rates with varying wind and temperatures (BBRI, Belgium), c) fully open window, set-up to measure ventilation rate and cooling as a function of time (BRE, UK) d) fully open window, set-up tomeasure cooling as a function of ti
As part of the Air Infiltration & Ventilation Centre's Numerical Database development programme, Wind Pressure Coefficient data are being collected from many published sources, much of which will contribute to the Centre's own Pressure Coefficient database. To ensure the compatibility and validity of the various data sets, a preliminary comparison has been carried out of the data in use. The work has concentrated on an analysis of the effects of Cp values, for vertical walls, on calculated wind driven infiltration and ventilation rates.
As the thermal performance of buildings continues to improve, air exchange will eventually become the dominant mechanism for building heat loss. Although, therefore, an essential parameter of the energy equation, ventilation is nevertheless vital forthe dilution and removal of pollution generated within buildings. An inadequate supply of fresh air or poor air distribution will result in high levels of indoor contaminants, discomfort and a poor living environment, it could also result in more serious health related problems.
Some guidelines on indoor-air quality specify a maximum allowable exposure to CO2. In a room ventilated by a mechanical extract system a control program on the CO2 concentration may, by anappropriate sampling strategy, supply information about the exhausted flowrate. This paper briefly outlines a simple analytical model for estimating the exhausted flowrate by measuring the CO2 concentration and keeping a record of the occupancy of the room.
A new turbinemeter is developed to be used as a ventilating rate sensor in livestock buildings. Starting from a previous sensor, which we introduced in 1983, several improvements were done tobecome a low cost air flow rate sensor with an acceptable accuracy of 60 m3/h in a range from 200 to 5000 m3/h and this for pressure differences from 0 to 120 Pa. This sensor can beintegrated in the climate control equipment of livestock buildings to improve process control.
In order to reduce the convective flow which is the principal responsible for the high indoor 222Rn concentrations, several mitigation technics have been developed and used in many countries. Since they don't always respond as expected, there is a need of instruments helping in their design and their evaluation. This paper suggests the use of a numerical code, based on the finite difference method, for the evaluation of 222Rn mitigation strategies in dwellings, It is supposed that 222Rn transport from soil into a dwelling occurs mainly by pressure-driven air-flow.
The performance of ventilation provision in subfloor cavities is relevant to the fields of energy efficiency, condensation risk, and air quality. Thorough programs of site measurements of ventilation rates by means of tracer gas tests are in general protracted and expensive, and it is quite clear that would be highly desirable to be able to predict ventilation rates given details of building design, ventilation provision, and d.egree of exposure.
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