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HVAC BALANCE Air Balancing - Call us at (800) 217-8437Variable Air Volume (VAV) systems are so varied and some are so complex that one set of balancing specifications cannot be written to cover all situations. We consider all situations and have experienced most of them at some point over our 20 year history. We check to ensure that registers and grilles are installed. We test and record system static pressures, suction and discharge. Balancing airflow throughout a building takes lots of time and practice. A design airflow is given for each individual air device and a balancing damper is used to decrease the airflow on outlets that are over there design flow. Closing down high volume grilles will increase or push airflow to other outlets that are low on airflow. The tricky part is getting that airflow to go were you want it to without increasing those grilles you have already turned down. Many things can influence airflow travel through a duct. Airflow will always take the easiest path, however the easiest path does not always leave a proportioned grille balance. That is why dampers are installed. When using dampers you should always use branch and zone dampers first. When all your duct branches have design airflow then you would use grille dampers. A dual duct system was popular in the early days of air conditioning. It had several advantages, but the disadvantages, like excessive energy consumption, led to its downfall after the energy crisis of 1973. The dual duct concept was fairly simple. A fan discharged air in a blow-thru arrangement that could either be directed through the cooling coil or the heating coil. What determined which path the air would take? Actually it was a device separate from either the fan or the coil, a device called the dual duct mixing box. 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. Most green builders already know their duct basics: (1) Duct leaks are very common; in many homes, duct leaks are responsible for significant energy losses, (2) For ducts located in an unconditioned attic, any leaks in the supply system tend to depressurize a house, while return-system leaks tend to pressurize a house. Either condition can cause problems, (3) Duct leaks outside of a home thermal envelope waste more energy than duct leaks inside a home thermal envelope, (3) Even if ducts are located inside of a home thermal envelope, duct leaks can still connect to the outdoors, and (4) It is much easier to seal duct seams during new construction than in an existing house. Kitchen Hood Grease Duct Leakage Testing is performed as a service to provide proof that the grease duct systems installed on a kitchen hood system has no leaks. We use only professional calibrated equipment to perform these tests to ensure the validity of these tests. Heating, ventilating, and air-conditioning (HVAC systems) account for 39% of the energy used in commercial buildings in the United States. Consequently, almost any business or government agency has the potential to realize significant savings by improving its control of HVAC operations and improving the efficiency of the system it uses. Safety factors for HVAC systems allow for uncertainties in the final design, construction and use of the building, but should be used reasonably. Greatly over-sized equipment operates less efficiently and costs more than properly sized equipment. For example, over-sized cooling systems may not dehumidify the air properly, resulting in cool but clammy spaces. It is unreasonable and expensive to assume a simultaneous worst-case scenario for all load components (occupancy, lighting, shading devices, weather) and then to apply the highest safety factors for sizing. |
