Search results
Results from the WOW.Com Content Network
The relationship between pressure and leakage air flow rate is defined by the power law model between the airflow rate and the pressure difference across the ductwork envelope as follows: q L =C L ∆p n. where: q L is the volumetric leakage airflow rate expressed in L.s −1; C L is the air leakage coefficient expressed in L.s −1.Pa −n
Cross-breezes work when two windows are opposite of each other. Cross ventilation is a natural phenomenon where wind, fresh air or a breeze enters upon an opening, such as a window, and flows directly through the space and exits through an opening on the opposite side of the building (where the air pressure is lower).
Displacement ventilation systems supply air directly to the occupied zone.The air is supplied at low velocities to cause minimal induction and mixing. This system is used for ventilation and cooling of large high spaces, such as auditorium and atria, where energy may be saved if only the occupied zone is treated rather than trying to control the conditions in the entire space.
minimum outside air The lowest amount of fresh air flow that can be allowed into a recirculating system. This limit is set to ensure that the interior air remains safe and comfortable to breathe. outside air damper An automatic louver or damper that controls the fresh air flow into an air handler and modulates to the most energy efficient setting.
Rectangular ductwork is covered by the ASCE "The Structural Design of Air & Gas Ducts for Process Power Stations and Industrial Applications". In the practical design of primarily round structural process ductwork in the cement, lime and lead industries, the duct size involved ranges from 18 inches (45 cm) to 30 feet (10 m). The air temperature ...
There is a pressure difference between the outside air and the air inside the building caused by the difference in temperature between the outside air and the inside air. That pressure difference ( ΔP ) is the driving force for the stack effect and it can be calculated with the equations presented below.
Power flue – Fanned flues use the pressure created by a fan to power the movement of outside air into the appliance and combustion products to external air. Thus air and flue ducts can be much longer, of smaller diameter, and include changes of direction. Most ducting is concentric; the air duct contains the smaller flue duct within it.
Downstream of the air handler, the supply air trunk duct will commonly fork, providing air to many individual air outlets such as diffusers, grilles, and registers. When the system is designed with a main duct branching into many subsidiary branch ducts, fittings called take-offs allow a small portion of the flow in the main duct to be diverted ...