Due to energy shortage and increased energy costs, there seems to be conflicting interest between hygiene and comfort on one hand, and energy economy on the other. Fortunately, it is possible to increase the ventilating air change rate in the zone of occupancy without increasing the air change rate for the whole room in question. Describes different methods for measuring and defining ventilation efficiency, and tests some of these methods in the laboratory, along with different ventilation systems.
Airflow window units are a combination of energy efficient fenestration and adjustable shading device, consisting of a double-glazed outer sash and a single-glazed inner sash, with venetian or louvered blinds in between. Space air is admitted
Uses model buildings to study external distribution of wind pressure and internal air flow. Compares air flow data with computed values derived from the pressure distribution data. Collects the pressure data obtained in a comprehensive study of wind loads on low-rise buildings and rearranges it in a form more suited to the computation of internal flows. Presents and discusses the methods emloyed in the reformulation and the results obtained. Briefly describes the development of design aids from which flow estimates could be made by simple hand calculations.
Performs tracer gas measurements and fan pressurization experiments on an 8-storied student residential building in order to determine the influence of wind as well as of stack effect upon air infiltration. Compares pressure and tracer gas distributions with those from a predictive infiltration computer model for high rise buildings.
Determines ventilation rates and intercell flow rates in naturally ventilated office building using multiple tracer gases. Subdivides the building into 3zones and seeds each zone individually with a different tracer gas. Monitors the time histories of the concentrations of all gases in each zone using non-dispersive infra red gas analysers. Calculates air flow rates from experimental data.
Reports the results of measurement of ventilation efficiency in a full scale model of a small office with a diffuse air supply, which can be used to improve ventilation efficiency and therefore reduce air supply rates. Steady state and transient definitions of ventilation efficiency are given. Finds that ventilation efficiency depends on air flow rate and heat gain in the office. Higher air flow rates give lower pollutant concentration in the ocupied zone but also more mixing between the occupied and under-ceiling zones.
Discusses the possible effects of wind, stack effect, vents and fans on air leakage, and the influence of air leakage openings and the location on the pattern of air flow through buildings. Considers the possible extent and location of condensation in relation to these patterns, as well as methods of controlling moisture entry and removal of accumulated moisture.
States that comparison of different methods of calculating the volumes of outdoor air entering a building through the window shows that the chief deficiency of the standardised method of calculation is neglect of the importance of the relation between building dimensions, the wind profile andthe resulting pressure distribution at the building. Proposes an approximation method which significantly improves the accuracy of the calculation and also permits the calculation of flow through buildings for each possible combination of the factors determining the flow.
Tests a method which determines the infiltration of air and radon from the soil to a building. Makes measurements of total air flow along with usual airtightness tests. Describes practical tests in a detached house with a raft foundation on a gravel esker, and determines the permeability curves for thewhole house and the raft alone, and also the permeability of the soil to air. Describes the way the results are used for determination of air infiltration in different climatic conditions, and tests different radon reducing methodsusing the previously developed system analysis.
Discusses the extension of an infiltration predicting technique to the prediction of inter-room air movements. Air flow through openings is computed from the ASHRAE crack method together with a mass balance in each room. Verifies technique by comparison to published experimental results. Results indicate that the simple model provides reasonable results for complex 2 way flows through openings. The model is as accurate as the available data, about+-20%.
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