Variable Air Volume Box with Hot Water Reheat | Commercial HVAC

Variable Air Volume Box with Hot Water Reheat
Variable Air Volume Box with Hot Water Reheat – The variable air volume box or VAV box is a commercial solution to adding multiple zones to large buildings. VAV boxes offer zoning solutions so that separate zoning demands or temperature selections can be maintained in different areas of the building.

If the president of the company wants the temperature in their office to be 70 degrees Fahrenheit but the vice president wants their office to be 74 degrees Fahrenheit then it is possible with the VAV zoning system as long as their VAV boxes are on different zones. (more…)

VAV Air Handler | HVAC Zoning

VAV Air Handler and HVAC ZoningVAV Air Handlers are ideal for providing zones in a commercial building. Office space typically has several offices and open areas that need to be conditioned for the comfort of the people working in those areas or offices. By installing VAV boxes and zoning the ductwork from those VAV boxes these areas and offices can be kept comfortable using a VAV air handler system. More on how VAV boxes work. (more…)

VAV Box Types Fan Powered and Shut Off

VAV Box Types Fan Powered and Shut Off VAV Boxes - When attempting to name the different types of VAV boxes we find there are different names given to VAV boxes by different people and we find that no one is on the same page when VAV boxes are definitively defined.

We have fan-powered VAV and non-fan-powered VAV’s and we have series and parallel VAV’s and we have VAV boxes with a hot deck and a cold deck that mixes and one of the last projects I worked on some of the VAV’s were referred to as shut-off vavs. Variable Air Volume Boxes (VAV Boxes) regulates airflow into zones using a primary air source from a VAV air handler.

VAV Box Types Fan Powered and Shut Off

  • Cool only single ducted series
  • Fan-powered single duct series with reheat
  • Fan-powered single ducted parallel with reheat - uses plenum air before using reheat for energy efficiency

Aside from the control aspect of VAV boxes, pneumatic, electric, electronic, or DDC, there are many different variations to VAV Boxes and we will attempt to define each type of VAV including offering a diagram of each type and matching it with a specific application. VAV boxes are simply an assembly of a damper, damper controls, and sometimes reheat such as electric heat strips or a hot water coil. VAV boxes get their primary air source from a central VAV air handler and then distribute air throughout a specific zone the VAV box controls.

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HVAC Control Transformer Bank | DDC Installation

HVAC Control Transformer BankHVAC Control Transformer Bank - This bank of transformers is being used to power several VAV box controllers. One of many VAV boxes is powered by one of these transformers. In most VAV box applications, the power for the control system is at the box and a properly sized transformer for VA load is used to power the controller. In this application, the VAV boxes were not fan-powered and line voltage was not available in the boxes. So a central transformer bank was used and a wire for control power was pulled to each VAV box. (more…)

Variable Air Volume Systems – Commercial HVAC

Variable Air Volume Systems - Variable Air Volume (VAV) systems are the best way to zone especially in large buildings. A VAV system with the proper controls and setup will help the building owner realize large savings in energy usage. There are many VAV systems out there set up in different ways. The most common set-up (for DDC) is, of course, usually the cheapest to install.

They have an air handler (DX or Chilled Water) which supplies the VAV Boxes with fixed pressure and temperature of the conditioned air. The VAV Boxes have electric reheat which will heat the air if that particular zone calls for heat (it is not uncommon to also find VAV boxes that have hot water reheat although this usually costs more to install but can save in energy costs). More on how VAV boxes work.

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