Describes a method for determining the rate of air change in a ventilated space using carbon monoxide as a tracer gas. Concentration of carbon monoxide was found by an infra-red analyser which proved to be very precise and sensitive and made it possible to carry out analyses in a short time. Air change rates were measured in a laboratory with open windows and with closed windows. Concludes that air change rates are greater with few large openings than with many small ones.
Describes measurements made to compare ventilation rates in six Belgian houses with both natural and mechanical ventilation systems using O2 and N2O as tracer gases. Ventilation rates were correlated with wind speed. Air leakage across individual components of the house was measured and from this the distribution of leakage areas calculated.
Reviews qualities desirable in a tracer gas for the measurement of ventilation rates in buildings. Reports experiments in which radioactive argon was used to measure the ventilation rate in a room. Results obtained agreed with simultaneous measurements using hydrogen as tracer. Suggests use of method for measuring ventilation rates in large buildings and use of krypton gas as an alternative to argon.
Describes how ventilation rates in two houses with recirculating air distribution systems were monitored by injecting CO2 tracer gas into the supply and measuring its concentration in the return air. In one house with solid concrete floor, normal windows and air bricks, ventilation rates were mainly dependent on wind speed. In the other with suspended timber floor and weatherstripped windows ventilation rates were much lower and mainly dependent on internal to external temperature difference.
Gives general account of Twin Rivers project summarising main findings from 1972 to date. Includes section on air infiltration. Measurements of infiltration rates were taken using tracer gas method and regression equation found for the data.
The measurement systems used at Twin Rivers for determining energy usage are described. These include a weather station, three different systems for the measurement of temperatures and energy-related events in a house, a tracer-gas based air infiltration measurement system and infrared thermography
Developes mathematical model of air infiltration based on crack flow equations. Describes measurements made on test house. Shows that actual pressure distributions in walls deviate considerably from values in guidebooks. Finds background leakage area of house by pressurizing house with electric fan and measuring pressures. Suggests two distributions for leakage areas. Measures infiltration rate using helium tracer gas, recording temperature and pressure differences. Concludes that comparison between prediction and experimental results is encouraging.
Describes the determination of infiltration rates for houses in Seneffe. Gives infiltration rates for individual rooms, found using O2 as tracer gas, and recording wind speed and direction. Determines global air renewal rate using N2O as tracer gas, by injecting gas through ventilators into all rooms and measuring concentration in each room. Calculates global concentration from individual measurements.
Measurements of the dynamic heat transfer in a four-bedroom townhouse were made under controlled conditions in a large environmental chamber to explore the viability of a computer program developed at N.B.S. labelled NBSLD for predicting heating and cooling loads and inside temperatures. Test house was factory-produced, of modular design and lightweight (wood) construction. Tests were performed with simulated outside summer, winter and autumn diurnal temperature cycles. Inside temperature was maintained at 75 f and the activities of a six-member family were simulated.
Presents description of an automated, controlled-flow air infiltration measurement system. This system measures total air flow, a volume per unit time, due to infiltration in a test space. Data analysis is discussed and the mixing problem analysed. Different modes of operating the system are considered : (1) concentration decay, (2) continuous flow in a single chamber and (3) continuous flow in a multichamber enclosure. Problems associated with the use of nitrous oxide as a tracer gas are described.
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