Variable Air Volume Boxes and VAV Terminal Units

Barcol-Air is the only European and world-wide manufacturer of all types of VAV systems.

There are 3 types of VAV system used in the market place today. All of these systems are designed around the VAV philosophy of load diversity, low turndown ratios, high efficiency/low running costs, use of free cooling, normal or low temperature air and zero maintenance. Set up correctly through the Building Management System, these all air systems will provide the most energy efficient method of providing fresh air and high cooling/heating load requirements for medium to large sized buildings giving close control to 0.5 - 1 C of set point. Each terminal unit can be fitted with any controls system (BMS) and electric or water reheat coils are fitted as standard. Control operation is of the pressure independent type complete with 24 point flo’cross sensor.


Standard VAV: Type NS, NB zero maintenance terminal units

Rectangular or circular VAV/CAV terminal with integral sound attenuator for low noise performance. 24 point flo’cross velocity sensor fitted for + 5% volume flow accuracy at 1 diameter from bends. Units can have multiple (4 outlets) or rectangular outlet configuration. General design criteria for 12 C primary air and t of up to 11 C to supply air diffusers at 50% primary turndown ratio with standard diffusers.




VAV Induction: Type NV, zero maintenance terminal units

Rectangular low height VAV terminal with integral sound attenuator. This unit can be used with normal or low temperature primary air temps(8 C upwards). The unit operates as a standard VAV unit but is capable of inducing void air to mix with primary air to give supply air temperatures of 12 C or more.

The induction effect allows a primary turndown ratio to 25% thus giving even more energy savings to the system all year round. Standard diffusers can be used due to the induction effect ‘creating’ higher secondary air volumes thus eliminating diffuser dumping. With no fan and no filters, this system is by far the best VAV system with the least maintenance.




Fan assisted VAV ; Type NX

Rectangular fan assisted VAV terminal complete with reheat coils and sound attenuator sections.

These units are used in conjunction with low temperature air 7 C upwards. They provide constant air volume to the space with VAV primary inlet turndown ratios to 15%.

These units have 24 hour fans and filters so maintenance/running costs are higher than the other VAV systems. Also the units are physically larger. Generally used in very high load areas but not for normal office density application.

redlaw vav system -redlaw clm linear diffuser variable volume

Barcol-air induction vav,standard vav,cav,dual duct terminal units

barcol-air catalogue variable air volume vav cav terminal units

VAV Induction Video Barcol-air, best low energy vav system in the market place

Redlaw vav system variable air volume clm klm diffuser

You will need Adobe Acrobat Reader to read these pdfs: you can download it free of charge from