What is the difference between VAV and DCV?

Perhaps you have heard of both VAV and DCV and thought about what really is the difference. We outline the different concepts and detail when you benefit from choosing one or the other.

VAV and DCV systems essentially fill the same purpose, to adapt ventilation and air conditioning to varying levels of activity in a premises. Generally speaking, it is possible to achieve higher energy savings and a better indoor climate with a more advanced system. But there are, of course, applications where simpler systems work well.

There are a number of concepts for different principles of ventilation control, but the three most common are:

CAV - Constant Air Volume or constant 
flow system VAV - Variable Air Volume or variable 
flow system DCV - Demand Controlled Ventilation or needs controlled system 

What are the differences and the advantages of the two alternatives?


VAV

  • Simple needs control - the air flow can vary over the operating time and is adapted to requirements eg. temperature or air quality
  • This often means lower investment costs for smaller projects compared to DCV
  • Often meets the requirements for simpler projects, such as pre-schools and smaller schools
  • Often gives a good energy saving compared to CAV

 

DCV

  • Advanced needs control - adjusts airflows and temperature depending on the needs and presence status of the premises, eg. with different operating requirements
  • Greater opportunity for custom comfort dependant on differentiated customer needs
  • Often it is possible to combine air and waterborne products for a complete indoor climate system
  • Strong contributing factor to a good classification in various certification programs such as BREEAM, WELL and LEED
  • Greater opportunities for energy saving, which is primarily an advantage in buildings with high energy consumption for ventilation and air conditioning

With both options you can both reduce your energy consumption and get a better indoor climate compared to CAV. A comparison of the air flow (m 3 / h) depending on the presence range in a specific room showed that a simpler on / off VAV system could lower the flow by 72% and a DCV system with a full 84% compared to a CAV system.

“A comparison of the air flow (m 3 / h) depending on the presence range in a specific room showed that a simpler on / off VAV system could lower the flow by 72% and a DCV system with a full 84% compared to a CAV system.”

A simpler VAV system can thus be fully sufficient in smaller projects where the requirement objective is not so advanced, and the investment cost is a crucial factor. For projects where the requirements for the indoor climate are higher and the building possible. To be certified according to any program more advanced DCV systems are required. With the DCV system there are also a number of functions that enable the type of smart buildings that are becoming more common, such as the world's most green and intelligent building, The Edge in Amsterdam. A better indoor climate increases according to the studies, the value of the building and at the same time the well-being and efficiency of those who use it.

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