Supply Secondary
Air Unit

Unidirectional Ventilation

Unidirectional ventilation unit (UVU) means a ventilation unit producing an air flow in one direction only, either from indoors to outdoors (exhaust) or from outdoors to indoors (supply), where the mechanically produced air flow is balanced by natural air supply or exhaust.

The units are important elements in saving energy in Industrial, Health, Distribution Centres, Warehousing, Pharmaceutical, and Data Centres.


This investment passes off in several ways:

  • Lower energy consumption
  • Lower investment for heat generation and distribution
  • Less damage to the environment


Where only supply air is required for a ventilation system, openings in the buildings envelope are used for extraction. The area is positively pressurised and a percentage of secondary air is also recirculated through the supply air handling unit and back in to the area served.

The supply unit comes complete with 2 dampers including fresh air intake damper and secondary air damper. The mix of fresh air and secondary air can thus be adjusted to suit the needs of the building.

Ancillary Items

Air filtration is always present in order to provide clean dust-free air to the building.

Direct heating, placed directly in the air stream, are direct heat exchangers and include those for gas-fired fuel-burning heaters or electric air heater batteries (EAHB).

Indirect Heating uses hot water or steam for heating. (Prime energy for heating is provided by central plant).

Smart Control System

Either our Smart Control System or the clients BMS may automatically modulate the fresh air and secondary air for optimum energy efficiency whilst maintaining desired fresh air requirements. This system works very well in buildings where the conditions can vary throughout the day, or seasonably. Where fresh air is not required, the mixing damper can be automatically set to full recirculation, again for optimum energy efficiency.



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