Make-up Ventilation Air System

By Author: Susann Terlitski
Total Articles: 30
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AB Blower Co. is an engineering company for air moving equipment. It developed a PT Power Tube Make-Up Air System - one of the most economical options for larger industrial plants ventilation air make up systems.

PT Air Make-Up fan system is a new ventilation concept. It utilizes some aerodynamic principles for supplying, tempering and distributing make-up air in a building in cold weather. It offers more efficiency, economy and comfort than most conventional make-up air units.

When exhaust fans are used to provide ventilation, both for industrial and process exhaust and personnel comfort, a negative air pressure is created within the building. This negative pressure causes several problems:

- Process exhaust systems are less efficient and may not work properly.
- Down flow can occur through gravity vents and result in the back venting of products of combustion from flues and stacks of heaters and process equipment.
- Drafts are created that are a dsicomfort to employees. Safe operating of outside doors may even be impaired.

Our Power Tube Fan Make-Up Air System solves all of these problems ...
... economically, even on the coldest winter day.

PT Fan System consists of a specially designed air supply fan, a wall housing and a motorized air inlet damper. A long polyethylene tubing is attached to the unit and extends horizontally inside building supported from wire. It has precision holes punched on both sides at specific intervals along its length and has an opposed end closed off.

Each fan housing assembly is mounted in the outside wall opening or connected to a roof air supply fan.

In the winter, conventional make-up air systems have to heat the cold outside air prior to introduction into the building. This is an expensive process in both equipment and continuing energy cost. The Power Tube Fam Make-Up Air System is a simplier system that utilizes waste3d building heat and basic earodynamic principles for supplying, tempering and distributing make-up air. And that makes it less expensive than conventional make-up air systems to purchase, to install and to operate.

When make-up air is needed, the motorized inlet shutter opens, the supply fan turns on and supplied fresh outside air inflating the tube for its full length. The air discharges from the punched holes in the tube located overhead as small high velocity jets which create turbulent mixing with the warmer inside air. As a result the outside air is effectively tempered before it reaches the worker level, creating a uniform draft free make up air system.

Normally several PT Fan systems are required for a building, depending on the size of the building, volume of make-up air required, size of PT Fan models selected. Additional heating, if required, may be furnished from conventional type space unit heaters positioned near the distributing PT tubes.

AB Blower PT Air Make-Up System has the following advantages over coventional make-up air units:

* Offers savings in initial investment and operating costs;
* Provides draft-free and uniform air distribution from along tube rather than blasting air from a single source outlet;
* Uses less energy due to lower horsepower for the same supplied air volume and because of friction loss of blowing air through a heat transfer system is completely eliminated;
* Easier and less costly to install, as PT Fan system is relatively light in weight ans the polyethylene tubing can be installed in a fraction of time normally required for conventional ventilation ducts;
* Eliminates coil freeze-up problems typical for AHU with heating hot water and steam heat exchangers;
* Reclaims overhead heat wasted in most buildings - through mixing of outside air with inside hot air;
* Very quiet, normally within 20 Fan Sones;
* Flexible in capacity, which is achieved by running only the required number of PT units based on the temperature inside the building;
* Provides a more comfortable eworking environment by maintaining gentle air flow and uniform temperature distribution.

Power Tube Make-Up Air Fans are available in Sizes 18 to 48 for for air flows up to 40,000 CFM.

PT Power Tube Make-Up Air System tube is constructed of thick woven high density polyethylene fiber(8 x 8) laminated with poly coating to a thickness of 6 Mils. It is 3.8 oz. per square yeard material. Burst strength is 118 Lbs per square inch. The material is flame retardant and complied with NFPA Standard 701. Tubes are available in two colors: blue and white. One end of the polyethylen tube is factory dealed.

Sufficient make-up air should be provided to balance exhaust from general ventilation and process ventilation. Usually several Power Tube Fans will be required, located to distribute air throughout the plant. If additional tempering of make-up air in specific plant areas becomes necessary, unit heaters can be added.

Additional information can be found at the AB Blower company web site http://www.abbblower.com/products/panel_fans.html

Susann Terlitski
Designer of Industrial Air Handling Units
AB Blower Co.
nis@primus.ca
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