English

Discusses the use of a regenerative air-to-air rotary heat exchanger (thermal wheel) for heat recovery in residential ventilation systems. Describes a small rotary heat exchanger designed to handle low air flow rates typical of residential houses. The heat exchanger is constructed of a light-weight honeycomb structure made of aluminium foil sheets. Laboratory tests of the heat exchanger showed a high sensible heat recovery effectiveness of the order of 85% with acceptable levels of pressure drop and cross leakage. Cost saving analysis showed significant savings even at today's energy cost.

Discusses materials and systems for reducing or eliminating air infiltration through identified leakage sources. Methods include caulking, adhesive/glass mat, weatherstripping, vent dampers etc. Gives recommended procedure for treating new and existing construction by pressurizing the building to detect air leaks, then retrofitting to reduce leakage. Cost effectiveness of the methods has not been reliably measured but the evidence suggests that many air infiltration reduction materials are highly cost effective. Gives bibliography of 233 citations.

Compares some existing performance requirements for air permeability and water-tightness of windows. Gives tables showing main European standards. Finds that a large variety of methods of test and grading systems is used and concludes that steps should be taken to unify the systems.

The Alberta Home Heating Research Facility consists of six uninhabited wood frame single storey modules with full basements. Describes the modules which are designed to test domestic heating strategies in a northern climate. Reports a series of preliminary measurements of infiltration rate using SF6 as a tracer gas and measuring the rate of decay of the gas. Future studies are planned using SF6 in constant concentration.

Notes that some of the main contributors to excessive ventilation in industrial buildings are external doors and loading bays. Discusses the choice of industrial doors to minimise energy loss. Discusses flexible doors, strip doors, loading bays, air curtains and door sealing.

Describes use of an acoustic method developed by Keast to detect air leaks. A loud source of sound is placed inside the building and a microphone, stethoscope, rubber hose or sound meter is used to detect places where anincrease in sound indicates air leakage. Finds method is effective in detecting simple leaks but will not spot complex paths through walls.

Reports tests on 4 different windows of air leakage and sound transmission loss. Expresses each of these two quantities by a single parameter and finds reasonable correlation between the parameters. Concludes, within the limitations of the method, that the air leakage class of a window can be deduced from field measurements of sound transmission loss, when the acoustical performance in perfect sealing conditions is known.

Describes the operating characteristics of a small aspirated concentration sensor based on a hot-film anemometer. Constant aspiration velocity past the sensor produces a linear output over a wide range of tracer gas concentrations, and a useful bandwidth of 0-500 Hz. A simple experimental technique for dynamic calibration is presented, with frequency response inferred from a model of the effects of molecular diffusion and hot-film response.

The requirement for better methods of predicting infiltration and natural ventilation rates has been reinforced by the incentive to reduce energy consumption in buildings. Natural ventilation is basically dependent on the effects of wind and temperature difference and on the resistance to airflow through the building. Discusses in detail these factors and highlights areas requiring further study. Briefly illustrates energy savings available by controlling natural ventilation.

Outlines factors influencing natural ventilation rates. Discusses techniques for measuring natural ventilation. Gives results of pressure measurements, made by the Building Research Establishment, of the leakage of houses and of tracer gas measurement of room ventilation rates. Discusses variation in air leakage rates with time. Gives results of measurements of the distribution of air leakage between components of the building shell.