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HVAC BALANCE Water Balancing - Call us at (800) 217-8437We test and balance air per plans and specifications. We check to ensure all duct work is complete. We test and adjust systems for design CFM recirculated air. 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. Outside-air quantity can be measured directly by pitot or electronic device. The outside-air damper modulates as required to deliver the minimum outside-air quantity. The technique measures outside air directly, independent of and unaffected by other control loops. The method has been criticized because it can be difficult to measure the low velocities involved accurately, but some of the difficulties have been overcome by advancements in hot-wire anemometers and related technologies. The method also does not address other control considerations, such as controlling the return fan. A return fan that runs too fast can depressurize a building. A return fan that runs too slow can result in outside air being sucked in through the relief/spill damper. Part-load performance of equipment is a critical consideration for HVAC sizing. Most heating and cooling equipment only operate at their rated, peak efficiency when fully loaded (that is, working near their maximum output). However, HVAC systems are sized to meet design heating and cooling conditions that historically occur only 1% to 2.5% of the time. Thus, HVAC systems are intentionally oversized at least 97.5% to 99% of the time. In addition, most equipment is further oversized to handle pick-up loads and to provide a factor of safety. Therefore, systems almost never operate at full load. In fact, most systems operate at 50% or less of their capacity. A Variable Air Volume (VAV) box, is a part of an air conditioning system. It is located inside the duct work. It is designed to control the air flow to a specific area, called a zone. The VAV regulates the volume of the air to the zone by opening or closing the damper, thus controlling the amount of conditioned air directed to the zone. Each zone in a building has a thermostat which controls the VAV, telling it when to open or shut the damper based upon the needs of the zone. Natural ventilation is the use of differences in air pressure that exist between the inside of a building relative to the outside of it, across the building envelope, to ventilate a building. These air pressure differences are created by natural forces such as wind and temperature. Air moves into and out of naturally ventilated buildings through windows, doors, vents and other openings incorporated into the building design and via infiltration / ex filtration. HVAC BALANCE offers test and balance services for the testing, adjusting and balancing of residential, commercial and industrial Heating, Air Conditioning and Ventilation systems. This service is a through checkout of all your equipment, duct work, control systems and all integral components that ensure that your HVAC systems are operating at peak operating conditions to save you energy, money and the environment. If the comfort zone is extended through natural ventilation and air movement in summer, and through lower air temperatures in winter (made possible by highly-insulated and, therefore, warmer wall and window surfaces), even higher savings can be achieved. For example, a typical office building minimally complying with the ASHRAE Standard 90.1-1989 might use 75,000 Btu/sq.ft./yr. The goal for many federal buildings is 50,000 Btu/sq.ft./yr. A highly energy-efficient building using conventional comfort could have an energy use of 40,000 Btu/sq.ft./yr. or even less. A building designed and operated with extended comfort strategies might only use 20,000 to 30,000 Btu/sq.ft./yr. |
