Wind shelter effects on air infiltration for a row of houses.

Once the flow-pressurization characteristics of a building are known, the largest uncertainty in predicting air infiltration is the effect of wind shelter from nearby buildings. To study the effects of wind sheltering a large data set of hourly air infiltration and meteorological measurements were made for a row of test houses located on an exposed rural site. This configuration produces strong variations in wind shelter as the wind direction shifts from along the row to perpendicular to it. A simple harmonic function is proposed for interpolating between highly sheltered and unsheltered wind directions for a building. Measurements show that the effect of strong wind shelter can change air infiltration rates by a factor of four, and strongly influence pressures that determine flow rates through passive ventilation intake and exhaust points. Measurements for buildings with varying leakage distributions are correlated to determine appropriate values for wind shelter coefficients.