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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 work closely with the contracting officer or inspector and make sure that notifications are prompt and accurate.
We check to ensure that all deficiencies are repaired.
We adjust all main supply and return air ducts to proper design CFM.
The simplest type of air system is a single zoned constant volume air handling unit satisfying only one zone sensor. These units are designed to condition the space temperature and humidity closely and efficiently and can be shut down when desired temperature has been reached to conserve energy. This type of unit can be either refrigerant cooled or by chilled water. A unit like this would be installed on a rooftop, floor mounted, or above the ceiling. These units would most likely be serving areas were the heat loads are even throughout, and in open areas such as classrooms, department stores, and computer rooms. They can also be effective in larger office buildings were multiple smaller units are used.
Gravity dampers or an exhaust fan can be used to control building pressure. An engineer can subtract the amount of exhausts (such as toilet exhausts) from the minimum-outside-air quantity and estimate the extent to which the remaining outside air could pressurize the building. During commissioning, pressurization set points can be determined by taking building-pressure field measurements with known outside-air quantities. One drawback is that the method does not truly control minimum outside air. The method uses a surrogate, such as the supply-fan capacity signal, as an approximation of total supply airflow. The controls use the surrogate signal to open the outside-air damper further as the supply fan slows, maintaining a nearly constant minimum outside airflow rather than a constant percentage of supply airflow.
The two-fan double-duct variable-volume system shares many of the advantages of the variable-volume reheat system. Pressurization is actively controlled and hoods have adequate safety monitors. Temperature control is adequate, and average ventilation rates are higher than for other variable-volume alternatives. This system has the disadvantage of requiring more room for duct work above the ceiling, and controlling a double-duct system is more difficult.
The traditional VAV box contains several parts which are necessary for operation. The casing is the outer box or shell, usually made from 22 gauge galvanized steel. The inlet is the connection to the duct coming from the Air Handling Unit. The outlet is the connection to the duct leading to the zone. Inside is the damper, or the metal door which opens or closes to control the amount of air flow needed. The damper controlled automatically by a motor, which is controlled by the thermostat. A thermostat is placed in the zone of the VAV, detecting the current temperature and instructing the VAV to open or close. This controls the amount of conditioned air entering the zone.
Building ventilation is the process of bringing outdoor air into a building, circulating it, and later purging it to the environment. The main purpose of ventilation is to provide acceptable indoor air quality by diluting and removing contaminants from the indoor air. Building ventilation is achieved by natural or mechanical means, or by a combination of the two.
Research clearly shows that when a fire occurs in a multi-compartmented building, the smoke from the fire is a far greater hazard to the occupants than the fire itself. Smoke can kill by asphyxiation or poisoning well before the temperature of the fire or smoke causes injury. Smoke also obscures vision, preventing occupants from finding safe escape routes and hindering the fire brigade search and rescue operation.
Employing high-performance HVAC equipment in conjunction with whole building design can result in significant energy savings. Typically, a 30% reduction in annual energy costs can be achieved with a simple payback period of about three to five years. And, if the payback threshold is extended to seven years, the savings can be about 40%. These figures apply to buildings that offer conventional comfort (e.g., 70 degrees F in winter, 76 degrees F in summer).
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