Search results
Results From The WOW.Com Content Network
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.
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]).
Note: the duct gas velocity is chosen to minimize duct dust dropout. Cement and lime plant duct velocity at normal operations is 3000 to 3200 foot per minute, lead plant velocities are 4000 to 4500 foot per minute, as the dust is heavier. Other industries, such as grain have lower gas velocities.
ANSI/AMCA Standard 510 - Methods of Testing Heavy Duty Dampers for Rating establishes testing methods to be used in measuring the performance of dampers generally described as “custom design,” “heavy duty” or “severe service” normally used in applications where elevated temperature, erosion and/or corrosion conditions exist ...
State based control can be thought of as an extension of the unit operation concept in the process industry. [7] Processes are designed with unit operations. With state-based control the control design is divided into units and those units further divided into states, with the proper operating discipline for each state designed in.
The UFAD system was originally introduced in the 1950s for rooms with high heat loads and raised floors systems for cable and equipment management (e.g. computer rooms, control centers, etc.). The system was introduced into office buildings in the 1970s in West Germany, with the addition of occupant-controlled localized supply diffusers.
In fluid dynamics, dynamic pressure (denoted by q or Q and sometimes called velocity pressure) is the quantity defined by: [1] = where (in SI units): q is the dynamic pressure in pascals (i.e., N/m 2, ρ (Greek letter rho) is the fluid mass density (e.g. in kg/m 3), and; u is the flow speed in m/s.
A duct leakage tester is a diagnostic tool designed to measure the airtightness of forced air heating, ventilating and air-conditioning (HVAC) ductwork. A duct leakage tester consists of a calibrated fan for measuring an air flow rate and a pressure sensing device to measure the pressure created by the fan flow.