Air Infiltration is caused by wind, stack effect, and mechanical equipment in the home (see Figure 1 below). The “stack effect” is when warm air moves upward in a building. This happens in summer and winter, but is most pronounced in the winter because indoor-outdoor temperature differences are the greatest.
What affects wind speed and direction?
The speed and direction of the wind is governed by three forces; the pressure gradient force (PGF), the Coriolis Force and friction. PGF is the force produced by differences in barometric pressure between two locations and is responsible for the flow of air from an area of high pressure to an area of low pressure.
What are two factors that affect wind speed?
Wind speed is affected by a number of factors and situations, operating on varying scales (from micro to macro scales). These include the pressure gradient, Rossby waves and jet streams, and local weather conditions.
What factor has the greatest effect on wind speed?
What is the greatest effect on wind speed? Air pressure has the greatest effect on wind speed. The greater the difference in air pressures between two air masses, the stronger the winds.
How can stack effect be reduced?
Reducing infiltration driven by stack effect is done by reducing airflow paths for stack effect airflow. The starting point is with vertical paths: holes around pipe penetrations up through buildings, holes into chases for piping and wiring and ductwork.
What is stack effect in HVAC?
The stack effect, also known as the chimney effect, describes the air movement in and out of buildings due to principles of physics. In the winter, warm air rises and escapes out of air leaks near the top while cold air is drawn in from the base… just like a chimney.
What are the factors that influence winds?
Factors Affecting Wind Motion:
