AIVC - Air Infiltration and Ventilation Centre

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Air leakage in split-level residences

Reports investigation of air change rates in two residences using helium as a tracer gas. Gives results of measured air change rates, wind speed and direction and internal to external temperature difference. Uses statistical method to compare results from the two residences and concludes that temperature coefficients were statistically different but that wind coefficients were not. Finds high dependence of infiltration rates on indoor to outdoor temperature difference and that values for air leakage obtained from current methods of estimation were lower than those actually experienced.

Retrofitting an existing wood-frame residence to reduce its heating and cooling energy requirements

Describes retrofitting a wood-frame residence in three stages to reduce its energy requirements for heating and cooling. The three retrofit stages comprised reducing air leaks; adding storm windows; and installing insulation in the floor ceiling andwalls. The house was extensively insulated to evaluate energy savings and changes in air infiltration rates. Concludes that retrofits produced only marginal reduction in air infiltration rates and attributes this to the original tight construction of the house.

A study of wind pressures on a single family dwelling in model and in full scale.

Compares wind pressures measured on a single-family dwelling with results obtained from a 1:50 scale model in a turbulent boundary layer. Shows that fluctuating components of surface pressures far exceeded mean or steady pressures and are well correlated over sizeable roof areas. Suggests that certain current provisions are marginal for tributary areas and excessive for localised area such as ridges, eaves and corners. Describes procedure for expressing loads on both localised and extended roof areas in terms of mean pressure coefficients and a peak factor.

Retrofitting an existing wood-frame residence for energy conservation-an experimental study

Describes retrofitting a wood-frame residence, having only limited insulation in the attic, to reduce its energy requirements for heating and cooling. The three retrofit stages comprised : reducing air leaks ; adding storm windows : andinstalling insulation in the floor, ceiling and walls. The housewas extensively insulated to evaluate energy savings and other performance factors. an economic model was used to evaluate the cost effectiveness of the retrofit options.

Well insulated airtight buildings.

Discusses reasons for making buildings air-tight and the requirements of the swedish building code. Gives examples of design solutions for detached houses and construction details for applying an internal vapour barrier consisting of a polythene sheet. Describes application to seven bungalows, resulting in air change per hour of 0.67 to 0.86. Subsequent measurements of ventilation and air velocity showed that in mechanically ventilated airtight houses the flow of ventilation air can be accurately controlled by the exhaust fan.

The optimum use of coniferous trees in reducing home energy consumption.

Refers to earlier work by Mattingly, Peters, Harrje and Heisler which indicated the possibility of reducing air infiltration by using sheltering devices such as fences, neighbouring buildings and trees. Reports use of wind tunnel air infiltration model to explore the effect of trees in a windbreak on a model home. Presents results of tests determining the effect on wind-induced air infiltration of the variation of various windbreak layout parameters. Introduces concept of turbulence generation as the mechanism of tree wind sheltering.

Measurement of ventilation using tracer gas technique.

Outlines ventilation measurements being made on two storey semi-detached houses using helium as a tracer gas. Describes measurement of decay rates in single rooms, the recirculation between two rooms and by summation the ventilation rate of thewhole house. Describes installation used to measure ventilation rates when homes are occupied without interfering with the normallife of tenants.

Air infiltration in ten electrically heated houses

Gives measurements of air infiltration made in ten houses in Indiana using helium as a tracer gas. Assumes linear dependence of infiltration rate on temperature difference and wind velocity and calculates infiltration rate per unit crack length. Change rates ranged from about 0.6 to 1.5 changes per hour.

Infiltration measurements in two research houses

Reports measurements of infiltration rates in two research houses in Minnesota under different wind, temperature and inside operating conditions using helium as a tracer gas. Suggests linear dependence of infiltration rate on temperature difference and wind velocity. Found infiltration rates varied from 0.1 to 0. 4 changes per hour

Measurements of air movements in a house using a radioactive tracer gas

Describes measurements of air change rates using radioactive krypton as a tracer gas in a domestic house. Reports measurement of air change rates for a single room heated by either an open fire or a central heating radiator. Examines effect of opening doors and windows and rate of flow up chimney. Found with all the doors open very large airflows from heated downstairs roomsto unheated upper storey, causing large heat transfer to bedrooms: if bedroom doors were shut very little warming of bedrooms took place.