Describes the results of an investigation carried out to determine the rate of fresh air infiltration that is experienced during the winter in a modern air conditioned office building. Six different methods were employed to estimate the rate of infiltration through the building, four by direct measurement and two by calculation. The methods of direct measurement were,tracer gas decay, measured air flow through one floor, measured air flow through one air conditioning unit and measured change on power demand.
Reports measurements made on windows in old blocks of flats in Sweden. Measurements were taken of air-leakage through 21 windows under different air pressures before and after the renewal of draught excluders between window frame and casement. Concludes that draught proofing of old windows is extremely effective. Heat flow through 18 double-glazed windows is also measured and two systems of converting double to triple glazing are studied. Conversion was found to improve u values by approximately 35%.
Reports of tests on wood windows and doors to determine their thermal performance with and without wind. Additional tests to determine air infiltration effects were made and concludes that air infiltration has very small effect at low pressure differentials. Notes discrepancies between test results and ASHRAE design values especially when a 15m.p.h. wind was present. Recommends development of uniform testing and evaluation methods.
Describes tests of air leakage performed on both prime windows and storm windows, separately and in tandem at wind velocities of up to 30.m.p.h. All types of windows were tested and upper and lower ranges for infiltration found.
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.
Details the retrofits at Twin Rivers, grouped into packages A,B, C and D. A,B and D reduced heat flow through attic and basement. B limits the amount of air infiltration from crack openings, especially round windows and doors, by the addition of Vinyl foam weatherstrips, caulking of window and door frames and adjustment of ill-fitting casements.
Notes heat flow through double windows due to temperature difference and air infiltration have usually been calculated separately. Tests combined effect of air pressure and temperature difference on three double hung prime windows in combination with various storm windows. Found that calculation of infiltration and transmission losses separately gives higher heating requirements than necessary and that air leakage increases with temperature differential. An overall heat transfer coefficient is determined
States that it is usual to assume a certain pressure difference across a window for a given wind velocity. Describes method of recording and instrumentation used to record wind speed and direction and pressure difference across two windows. Gives results of measurements showing dependence of pressure on winddirection. Shows that stack effect, even in buildings of moderate height, may be of sufficient importance to require a different allotment of heating capacity between lower and upper floors.
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