How VAV Boxes Work? A Variable Air Volume box is typically installed in commercial buildings and provide heating and cooling for occupants. There are different types of Variable Air Volume boxes but how a Variable Air Volume box works is fundamentally the same from one Variable Air Volume box type to another. Essentially a Variable Air Volume system allows a design engineer a way to zone large areas in work spaces such as office buildings and other places where there are large spaces that need heating and cooling or simply just cooling in rare cases. The concept is simple but making it energy efficient and keeping everyone comfortable has taken some time from the inception of Variable Air Volume box. Related Link: VAV Air Handlers - HVAC Zoning How VAV Boxes WorkThermostat and ControlsIn many cases, a Variable Air Volume box is nothing but a sheet metal box with a damper and controls inside a control panel. A thermostat connects to the controller while the controller positions the damper based on programmed inputs and variables that include air flow and temperature.

Some Variable Air Volume boxes also have a heat source inside the box. The heat source in many Variable Air Volume box is typically electric but can also be a hot water coil. The thermostat and the controller will also turn on the heat whenever the temperature in the space falls below the set point as determined by the thermostat and pre-programmed temperature limitations in the programming. Usually, the building engineer or maintenance staff controls the temperature limitations in the program. This prevents occupants from running the thermostat above certain settings that are unreasonable and possibly overload the HVAC system. These limited set points are usually within reasonable ranges for most peoples’ comfort factor.How VAV Boxes Work - VAV Air HandlersThe air that is supplied to a Variable Air Volume box comes from a large air handler and central duct work. The air handler must have the ability to supply the Variable Air Volume boxes with a variable amount of air as the dampers in the Variable Air Volume system will modulate to different positions based on set point requirements.

When the box is in cooling mode the damper will modulate to a nearly fully open position as air conditioning or cooling requires more air flow. Heating requires less air flow so the damper will modulate to a minimum position. The air handler blower fan needs to modulate to vary the air flow depending on demand. Typical Variable Air Volume boxes have a flow sensor inside them to measure air flow. The air flow and temperature variables control damper position based on temperature demands and C.F.M. demands. Another air pressure sensor inside the main duct that supplies air to the system measures the pressure inside the duct. There is a pressure set point inside the program of the air handler control. The air handler will ramp up and ramp down the air handler blower to maintain the duct set point requirement in the program.Related Link: Variable Air Volume Systems and DDC Controls (opens in a new window) How VAV Boxes Work - ConclusionFinally, in conclusion, Variable air volume systems provide comfort for many people working in commercial buildings.

The system is different than the air conditioning and heating systems in our homes but these systems work well and provide good comfort. The systems provide zoning for large work areas such as office spaces and other large work areas and office buildings.ac unit comes on but fan not turningMore on VAV Boxes can be found here.air conditioning outside unit not coming onHow VAV Boxes Worksmall floor ac unitEdit ArticleHow to Understand the Basic Operation of the Home Air Conditioning System Air Conditioning is a process where heat is removed from an area that it is not wanted. To an area where it makes little or no difference to the user or homeowner. This article will breakdown the four basic components and explain how they work in conjunction with each other.

Understand what the compressor does. Understand the role of the condenser. Note the metering device. Understand the role of the evaporator coil. Make sure that the thermostat is set to what is being called for. Hard to cool the home when the thermostat is set to heat! All systems have a required range to how much refrigerant is needed to operate the system properly. The number one mistake of a homeowner is that the system is not cooling properly and needs more refrigerant. Simply adding refrigerant to a system may not be the fix. In fact it could cause more costly repairs and maintenance to the homeowner than originally needed. All servicing and repairs need to be accomplished by a trained and/or certified company or individual. Never open refrigerant lines without the use of proper equipment and gear. (Gloves,Safety Glasses,Refrigerant Reclaim Tank, Manifold Gauges) It is a federal violation to purposely vent refrigerant gas into the atmosphere.

Jail time and fines are possible if caught. Refrigerant is very dangerous to handle without proper storage and knowledge of how it works. Design Engineer - Motors and DrivesWhat exactly is an ac drive and just how does it work?21st February 2013 Benefits of Green Building Benefits of Solar Energy ASHRAE Green Standard 189.1 A commercial solar energy system generates electricity from the sun’s rays to power a building’s HVAC system. Made up of photovoltaic (PV) cells, the system’s solar modules harvest the sun’s energy and convert it into electricity that can be used to power HVAC units, lights, computers and other electrical devices. The two main types of solar power systems are stand-alone and grid-connected (or utility-interactive) systems: The stand-alone systems are designed to operate independently of the electric utility grid and sized to supply certain DC or AC loads. In many stand-alone solar power systems, batteries are used for energy storage.

The grid-connected power systems are designed to operate parallel to, and interconnected with, the electric utility grid. This allows AC power produced by the solar system to either supply electricity to the building, or back-feed the grid when the solar system output is greater than the building’s electrical demand. In many states, this may allow business owners to take advantage of incentives to lower operating costs. The SunSource® Commercial Energy System is a grid-tied PV system that uses Lennox’ solar-ready, 18 SEER Energence® 3- to 12.5-ton commercial rooftop unit as its platform. By adding up to 6 solar modules to an Energence unit, an effective efficiency of 34 SEER or beyond6 may be achieved. Each Energence rooftop unit can be equipped with up to 24 solar modules. The solar modules use built-in microinverters to convert the captured energy from DC power to AC power. The solar modules feed electricity directly to the solar-ready rooftop unit at a single point of connection, using the converted power to run the building’s central heating and cooling system.