Increased air tightness in new energy-efficient housing has led to serious problems with excessive indoor moisture in winter as well as with other trapped indoor air contaminants. Heat recovery ventilation systems are being used increasingly

The various meanings of ventilation efficiency are briefly summarised. The residual life time of a released tracer gas is chosen as the most meaningful and convenient basis for local efficiency measurements in large, occupied, mechanically ventilated buildings. Measurements were carried out in ten public swimming pool halls. Sulphur hexafluoride tracer gas was released from a 20 ml syringe at various locations around the pool hall and the integrated concentration with respect to time was measured at the exhaust air duct. This was extrapolated to infinite time using the measured decay rate.

Air infiltration flows into different zones of a building can be measured with the constant concentration technique by injecting a metered amount of tracer gas t o hold the concentration of the gas constant. The control and estimation algorithm used to calculate the injection rate is designed using classical transform and optimal estimation methods. The ability of the control algorithm to keep the concentration constant and to accurately measure time varying infiltration flows is demonstrated using digital computer simulations and laboratory experiments.

This paper describes a preliminary investigation of the validity of a means of calculating the ventilation rate of a large enclosure from experimental data. It was assumed that the air in the enclosure is not perfectly mixed. The measurement method selected was tracer gas concentration decay. Thecalculation of ventilation rate was performed by "least squares" fitting of a model to the observed tracer gas concentrations. Simulations of tracer gas concentration decay measurements were performed with varying initial distribution of tracer gas.

In this paper ventilation of attics and crawl-spaces is investigated theoretically. Ventilation rates and temperatures of the spaces are calculated by means of flow balance procedures. Flow characteristics of ventilators and openings for attics and crawl-spaces are far from well known, so a laboratory investigation on pressure drops across such devices was undertaken and reported in the paper. As convective flows from the heated part of a houseinto a colder, ventilated space can create moisture problems this situation has been investigated extensively.

Several physical phenomena which may contribute to moisture migration from the crawl space to the living spaces in houses are outlined. Results of two projects to monitor moisture migration are presented.

Reviews the papers on air infiltration and ventilation research presented at the ASHRAE annual meeting held in Honolulu, Hawaii, in June 1985. The twelve most significant papers on multizone infiltration and air leakage are discussed at length and other infiltration-related papers mentioned. Authors' abstracts for the twelve symposium papers plus seven technical papers are presented.

Several infiltration models treat the complexity of air flows in multizone buildings, but most of them are written as research tools and are not generally available or user-friendly. Professional engineers and architects are in need of a simplified multizone infiltration model. This paper describes the first step in Lawrence Berkeley Laboratory's development of a multizone infiltration model for calculating the air flow distribution of a building without using any iteration procedure.

This paper discusses the indoor formaldehyde levels in two groups of houses. With the exception of the heating and ventilation systems, the house construction, formaldehyde sources and occupancy were similar for the two groups, One group (A) used electric baseboard convective heaters for space heating and semi-ducted heat recovery ventilators (HRV) for supplying outdoor air and exhausting indoor air , The second group (B) had electric forced-air furnaces with a ducted air supply to every room, Outdoor air was drawn in via a connection to the return air ductwork.

The R-2000 Super Energy-Efficient Home Program is a cooperative industry/government initiative sponsored by Energy, Mines and Resources Canada (EMR) and delivered by the Canadian Home Builders Association. The program supports building industry development, training of builders and the construction of energy-efficient houses incorporating high levels of insulation, a well sealed air barrier and mechanical ventilati on systems with heat recovery. In 1983, with assistance from the Buildings Energy Conservation Sub-Committee (B.E.C.S.