Until recently, natural ventilation was adequate for the indoor air environment of buildings. Today, with added insulation and tighter building envelope standards, indoor air quality is more dependent on mechanical means. The conventional and new control strategies for indoor environments are reviewed, and the point is made that good indoor air quality is attainable with cost effective means if the proper constraints are maintained. To improve control strategies, several suggestions are made:< 1.
The uncertainty of measurement results of air velocities in air-conditioned rooms generally is very high. A considerable part of the measurement errors are caused by the evaluation methods. It is shown that the accuracy of results can be ameliorated by using suitable statistical methods without increasing the effort. In this case binomial distribution gives better results thenGaussian distribution. To optimize the duration of measurements the most favorable reading interval must be determined. This time interval can be defined by the autocorrelation function of air velocity.
The method to calculate flow processes in multi-storey buildings having uniform storey arrangement(residential and office buildings) can be simplified to an extent enabling calculation by hand. Nomographs are given to calculate flows in sectional and central corridor buildings. The air flow rates depending on the action of wind, buoyancy and exhaust air plant operation can be derived from these nomographs for different combinations of flow resistances of the buildings. The latter factors may be included in thecalculation either individually or in any combination.
Sets of hourly data, representing the long term mean of both temperature and solar radiation, have been prepared for 21 U.S. metropolitan areas. The 8,760 sequential hourly values for all weather elements, including solar data, have been placed on magnetic tape for use in computer calculations of energy requirements.
Reviews different lightweight structures' abilities to store heat. Shows a cutaway drawing of a single-family dwelling illustrating how stored heat is distributed. Relates heat storage capacity to structural density. Notes the importance of air distribution in attaining efficient heating.
Measurements were undertaken of basic indoor air pollution in the childrens' room in 39 occupied flats, built within the past 20 years, and in seven newly-built one-family houses ready for occupation.
The structural design of glasshouses must provide for safety from wind damage while permitting maximum light transmission to the crop. A literature review of codes of practice, recommendations and data concerning wind loads on buildings showed several different procedures for describing the wind speed near the ground and predicting design pressures on low profile buildings.
During an extensive programme of sound insulation tests on a house near Manchester Airport the opportunity was taken to measure the field performance of partially open dual glazing. The results show an increase in insulation of up to 3dB(A) when compared with predictions based on laboratory SRIs. Also reports measurements of the ventilation rate in bedrooms with one window partially open and all other doors and windows closed. Measurements were made using nitrous oxide as a tracer gas.
The performance of an HVAC system's air-to-air energy recovery exchanger is defined primarily by the exchanger's effectiveness and pressure drop. The effectiveness is dependent on several parameters such as the supply and exhaust mass flow rates and the energy transfer characteristics of the device. Because of this combination, performance data must be established for each individual type of device.
An attempt was made to make the super-insulated Saskatchewan Conservation House as air-tight as possible, to avoid heat loss. By lapping all joints in the vapour barrier over solid backing, by continuous sealing of all joins, and by protecting the vapour barrier with solid covering, the natural air-change rate(A/C)was decreased to 1/20 change per hour. At this rate, induced air change was necessary to control odour and humidity. Most of these details could be modified to make any insulated house air-tight.
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