Search results
Results From The WOW.Com Content Network
An airflow window is composed of at least two panes of glass and a cavity between them that allows the flow of ventilation air. They operate on similar principles to a double-skin facade, but on a smaller scale. [1] [2] The general idea is to improve the energy efficiency of a cavity window by heating or cooling the cavity with ventilation air.
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.
It can be successfully applied to air flow in lung alveoli, or the flow through a drinking straw or through a hypodermic needle. It was experimentally derived independently by Jean Léonard Marie Poiseuille in 1838 [1] and Gotthilf Heinrich Ludwig Hagen, [2] and published by Hagen in 1839 [1] and then by Poiseuille in 1840–41 and 1846. [1]
Displacement ventilation is best suited for taller spaces (higher than 3 meters [10 feet]). [2] Standard mixing ventilation may be better suited for smaller spaces where air quality is not as great a concern, such as single-occupant offices, and where the room height is not tall (e.g., lower than 2.3 meters [7.5 feet]).
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).
For example, given a 150 m 2 building with an airflow of 180 m 3 /h this could result in about 47 liters of water accumulated per day. Ventilation efficiency is determined by design and layout, and is dependent upon the placement and proximity of diffusers and return air outlets.
The original designs were in the form of a fixed slot near the leading edge of the wing, a design that was used on a number of STOL aircraft. During World War II, German aircraft commonly fitted a more advanced version of the slat that reduced drag by being pushed back flush against the leading edge of the wing by air pressure , popping out ...
The relationship between pressure and leakage air flow rate is defined by the power law between the airflow rate and the pressure difference across the building envelope as follows: [16] q L =C L ∆p n. where: q L is the volumetric leakage airflow rate expressed in m 3 h −1; C L is the air leakage coefficient expressed in m 3 h −1 Pa −n