Why is it necessary to put reheat coils in VAV boxes?
Why is it necessary to put reheat coils in VAV boxes?
Reheat is used sometimes for humidity control, and sometimes for occupant comfort. The latter use happens when zone cooling loads are low and too much cold air is supplied to a space. In a VAV system, a damper modulates the amount of cool air supplied to the zone.
What is a cooling only VAV box?
Cool Only Single Duct Series (non-fan powered) This was referred to as a cooling-only box and was connected to the primary duct and led to a zone within the floor of a multi-story building. It had no reheat nor did it have a way to mix plenum air with the conditioned air coming from the VAV air handler.
What is bypass VAV?
Bypass VAV system responds to changing cooling or heating requirements by varying the quantity or volume of air delivered to each zone. An HVAC unit delivers a constant volume of air to the system. A Bypass VAV box provides constant or variable airflow depending on the temperature demands of the space.
Do VAV boxes have reheat coils?
Since there is no reheat coil, shut-off VAV systems do not provide heating capability during periods when the building is occupied. The VAV box is usually allowed to reduce the airflow to zero during periods of no cooling load.
What is VAV reheat?
Variable air volume (VAV) with reheat systems provide conditioned air to each zone at a constant temperature, typically 55°F. The amount of air varies to match the heat gain from equipment, lights- exterior and people. A damper (such as a pre-manufactured VAV box) adjusts airflow at each zone.
Do Vavs Have filters?
Filter (for fan-powered boxes) – usually included when a fan draws into the VAV box from the plenum or other return-air source.
What is a VAV system?
VAV systems supply air at a variable temperature and airflow rate from an air handling unit (AHU). Because VAV systems can meet varying heating and cooling needs of different building zones, these systems are found in many commercial buildings.
What is a reheat VAV?
