Parts 2 and 3 of a series of articles. Describes office buildings with natural and mechanical ventilation systems mentioned in part one, where the mechanical ventilation plus humidification and cooling is used only during the coldest parts of the winter and hottest parts of the summer. Provides comparative cost analysis for the building. Discusses design criteria to take account of fullor part time natural ventilation. Treats maximum room depths, window types,external and internal doors, furniture, room layouts.
Reports conclusions from projects investigating the tightness of buildings sponsored by the Ministry of Trade and Industry. Describes factors influencing ventilation such as size and shape of building, location, distribution of leakage points, interior air flow paths and the design and control of ventilation. Wind condition and temperature difference are the only driving forces in natural ventilation, in mechanical ventilation the temperature has only a limited influence but the wind may cause considerable draught in an untight building.
Describes a detailed simulation program for estimating heat loads and room air temperatures of a residential building. Sets out the algorithms and the example simulation of a house by the program. As room surface temperaures and natural ventilation are important factors in considering the thermal environment and the heat load of the room, they are treated more rigorously than in a previously developed program.
Describes some new theoretical and experimental techniques developed by British Gas to investigate the ventilation of buildings. These include:< 1. The multi-cell model "vent" for predicting ventilation rates< 2. "Autovent", the multi-cell constant concentration tracer gas technique used for measuring ventilation patterns in buildings.< 3. Pressurization techniques for measuring air leakage in buildings.< Gives a selection of results from applications of these techniques to show their scope.
Measures the air change rate in 2 atrium houses and in 6 terrace houses. Examines the possibility of allocating the air change to particular rooms by correctly placed and operated exhaust ventilation and ventilation openings. Concludes that in dwellings with mechanical exhaust the fresh air change rate only depends slightly on the ventilation openings being opened or closed, and that it is possible to direct fresh air flow into different rooms if the doors within the house are not tight.
Uses a validated multi-cell mathematical model of air infiltration to analyse the influence of various ventilation strategies on air distribution and energy demands. Assesses the performance of both natural and mechanical systems for two sets of climatic conditions and for two levels of airtightness. Shows that natural ventilation rates are highly dependent on climate. Additionally, air movement is a function of wind direction and stack effect.
Proposes a new experimental technique for investigating the natural ventilation potential of new building designs. The method tests scale models of ventilated buildings outdoors in the natural wind. Results from this method agree closely with data from a similar full-scale building. Discusses use of this method by building designers.
Describes large-scale field studies to investigate the effectiveness of measures to prevent condensation in some 4-storey blocks of walk-up flats in Stirling. The remedial measures in the blocks of flats are improvement of thermal insulation
Discusses whether air conditioning could be replaced. Treats the evolving concept of constructing office buildings designed to meet comfort conditions by natural ventilation, with mechanical ventilation, cooling and humidification applied only during the coldest parts of the winter and hottest periods of the summer. Describes the practical application of this concept to three office buildings in West Germany.
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