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.
States that in a tight house with a vapour barrier, an air management system is needed to provide fresh air and remove the build-up of moisture generated by the occupants. Briefly describes a typical air management system,incorporating an air-to-air heat exchanger, and discusses the need to provide an acceptable ventilation rate, which controls pollutant level but minimizes heat losses.
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.
Defines requirements for suitable indoor air quality and examines the technical and economical possibilities of suitable methods of ventilation. Differentiates between densely populated places (meeting places) and others of low occupancy, such as offices and living rooms. Finds that the most efficient way of satisfying hygiene requirements is by controlled air renewal, and that to achieve this mechanical ventilation according to DIN 1946 should be installed.
Measures air change rates in a 2-storey detached house with operation of various types of mechanical fresh air ventilation systems. Studies 4 systems, including 2 balanced systems and 2 exhaust-only systems. The forced ventilation rate is controlled at 0.15, 0.25, 0.4, or 0.5 ach. Develops expressions for the test house relating the house air change rate under winter conditions to the forced ventilation rate and the infiltration rate due to wind and temperature difference.
Stresses need to introduce sensible energy conservation measures into building and warns against superficially attractive solutions. Discusses reduction of ventilation heat loss by installation of mechanical ventilation incorporating heat recovery. Illustrates a mechanically ventilated dwelling with fresh air drawn into living areas and exhaust air leaving via the kitchen and WC. Treats further examples of mechanical ventilation which are adjusted according to necessary ventilation rates. Concludes by discussing trends in building construction concerned with conserving energy.
Investigates excessive energy consumption in a house mechanical ventilation and heat exchanger. Explains why the house consumes so much energy. Analyses the ventilation system and defines a "coefficient of performance". Such a factor could characterise the energy requirement of a ventilation system. Emphasizes that the ventilation system is to be regarded as an entire system and that a certificate for the exchanger does not guarantee that the totalsystem will perform satisfactorily.
Provides basis for planning and installing plant for maintaining indoor climate based on previous draft which is based on earlier Danish Standard. Refers to several salient design criteria including leakage factors at given test pressure, maintenance of climate parameters, air quality, anticipated energy consumption. Gives example table for requirements of building in terms of m2/person depending on application. States example tolerances of air flows.
Notes that many air conditioning and industrial installations function inefficiently since too little attention is paid to air movement in a room. Compares effect of inlet and exhaust air devices. Considers reduced ventilation need if pollution can be eliminated or reduced. States that ventilation efficiency is an indication of how efficiently the air is used in the occupation zone and that the air supply to a zone determines ventilation efficiency. Illustrates various forms of ventilation.
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