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HVAC BALANCE Heating, Venilation & Air Conditioning - Call (800) 217-8437
HVAC BALANCE Frequently Asked Questions (FAQ) - Call (800) 217-8437
We test and adjust blower RPM to design requirements.
We test and record motor full load amperage.
We adjust all main supply and return air ducts to proper design CFM.
In a rectangle duct traverse it is important to get an equal number of readings to cover the whole cross section of the duct. Drilling the correct number of holes and spacing the holes correctly is the most important part. The first step is finding the area of the duct in square feet.
Dust and airborne particulate media can cause health and safety problems, facility maintenance challenges and damage to engines and electronics. We will design the appropriate system for your applications, ensuring full capture in constant air volume control to extract and filter the air continuously during applications, whether they are conducted stand-alone, in glove box enclosures, spray booths or in entire rooms acting as enclosures.
Constant air volume systems are consistently used on medium to large projects to supply regulated fresh-air requirements to each zone/floor as well as extracting used air from the building. Constant volume units are used particularly on Fan Coil projects to deliver specific fan coils and zones with ‘guaranteed’ fresh air volumes. These can also be re-set via the BMS in order to accommodate change in fresh air requirements. All units are pressure independent and can be placed anywhere in the system and used with any BMS.
The supply air temperature set point for a single-duct constant air volume air handling unit (AHU) is often reset based on either return air temperature or outside air temperature in order to reduce simultaneous cooling and heating energy consumption. Both reset strategies make engineering sense as long as the reset schedules are reasonable. Quite often the decision to use one over the other is made with the assumption that they will both achieve some sorts of energy savings. However, the impact of these two strategies on AHU energy consumption could be very different. A comparison of these two commonly used supply air temperature reset strategies for a single-duct constant air volume system is presented in this paper. It is shown that from either the building energy consumption or building comfort point of view, the reset strategy based on outside air temperature is inherently better than that based on return air temperature. Significant amount of heating energy savings can be achieved by switching from return air temperature based reset to outside air temperature based reset.
In many buildings, the air distribution system also includes a return air system so that conditioned supply air is returned to the AHU (return air) where it is mixed with supply air, re-filtered, re-conditioned, and re-circulated throughout the building. This is usually accomplished by drawing air from the occupied space and returning it to the AHU by: (1) ducted returns, wherein air is collected from each room or zone using return air devices in the ceiling or walls that are directly connected by duct work to the air-handling unit; or (2) plenum returns, wherein air is collected from several rooms or zones through return air devices that empty into the negatively pressurized ceiling plenum (the space between the drop ceiling and the real ceiling); the air is then returned to the air-handling unit by duct work or structural conduits.
A key part of fire safety measures is to pressurise areas used as escape (namely stairwells) to prevent smoke entering the area. The design of these systems is complicated, because as people enter and leave the stairwell during an emergency there is an intermittent loss of effective pressurization. The system supply fan should have sufficient capacity to provide effective pressurization and prevent smoke entering the stairwell. Balancing this there should also be a method of preventing over-pressurization, which makes doors difficult to open.
The term HVAC refers to the three disciplines of Heating, Ventilating, and Air-Conditioning. A fourth discipline, Controls, pervades the entire HVAC field. Controls determine how HVAC systems operate to meet the design goals of comfort, safety, and cost-effective operation.
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