Industrial High Capacity Air Curtains

In the retail environment, research has shown that anThe most effective air curtain design for insect control
open door increases trade by up to 40% as it is anhas a nozzle that can angle the air stream away from
invitation to come in and shop yet retail stores andthe area to be protected. An angle of about 20 from
supermarket air-conditioning systems arethe vertical is usually optimal. The unit should meet or
'energy-hungry' so it would therefore seem logical toexceed UK Department of Agriculture and US Federal
save as much of the cold air as possible, consideringDrug Administration standards, which call for an air
the cost to make it cold in the first place. Publicstream of 50 mm to 120 mm wide at the nozzle,
buildings, like airports and convention centres, whichcapable of producing a minimum velocity of 8 m/s of
have high demand air-conditioning systems need toair 1 m above the floor and across the entire door
have open doors to allow access and, while someopening to ensure there are no gaps for the insects to
facilities have motion detector-activated sliding doors,enter.
usually of glass, this solution is costly, thermally not veryApart from flying insects, air-curtain manufacturers say
efficient and generally just a way of reducing draughts.rodents are also discouraged from entering a building.
Air curtains are widely accepted across NorthThey claim that rats, mice and other furry intruders do
America and Europe as a standard fitment in publicnot like the sensations of an air curtain on their fur and
buildings, retail stores and industrial applications such aswill avoid it!
coolers, freezers and cold storage facilities. Air curtainsDesign and installation
are generally associated with retaining heat energy inThe construction an design of the equipment that
cold climates, and the energy savings are substantial.generates an air curtain is quite simple - a cross flow
The idea of having an invisible barrier across theor axial fan, driven by a constant or variable speed
doorway to enable unimpeded access yet effectivelyelectric motor contained in a simple enclosure with an
prevent temperature flow, dust, odours and insects toair inlet and outlet, sized to produce a rate of flow to
cross, is appealing in itself but add to this thesuit the opening and the velocity required to prevent
cost-saving in reducing energy use and the ideaheat transfer.
becomes more compelling, especially as air curtainsOff-the-shelf models are available from a number of
are relatively inexpensive items.suppliers and units are also custom made but, where
Appropriate for industrial applicationswide entrances are involved that exceed the capacity
Keeping warm air out of insulated cold stores orof one fan unit, tow or more are stacked side by side
refrigerated facilities is the Number 1 objective yet a(or on top of one another in the case of side mounting
mockery is made of this premise when freezer ofof very tall openings) and operated simultaneously,
chiller doors are left wide open and, in some cases,meaning that there is probably no limit to the size of
chocked open to facilitate the movement or storagethe opening that can be accommodated.
of perishables.By directing a jet of air either from top to bottom or
Properly installed air curtains cut cold air loss andhorizontally across a doorway, this invisible 'barrier'
reduce humidity, thus reducing the load on refrigerationreduces the rate of heat and moisture flow through
or air-conditioning plant and thereby saving energy bythe opening and, according to independent research
reducing compressor running time, maintenance, gasconducted by the US-based Refrigerated Research
and recharging intervals. These units are an alternativeFoundation and the University of Illinois, this can be as
to fast-acting roller doors and PVC slat curtains, andmuch as 60% to 80% in refrigerated facilities such as
can be situated above or to the side of industrialcold storage buildings, cold rooms and freezers.
doorways to create a powerful seal across theThese simple devices can be retrofitted or specified
opening, keeping cold air in while providing completeas part of the initial refrigeration or climate control
visibility and access. This means that forklift driversdesign, reducing compressor running time or using a
don't have to get out of their cabs to open and closesmaller capacity unit to achieve the same
doors so that moving from one area to another is a lotperformance.
easier and productive. Unlike plastic slat curtains, whichA variety of installation options are available to cater
quickly become opaque with use, an air curtainfor building and architectural features such as
provides 100% visibility at all times. Units have beensuspended ceilings but the most common is simply
installed in loading bays, factories, hangars andbolting the unit to the wall above the doorway and
production facilities, such as food processing andconnecting a single phase supply and switch to the unit.
pharmaceuticals, where differential temperatures arePower consumption is negligible for a normal sized
encountered overseas.doorway opening - about 300 W. Some units can
Insect an pest control a benefiteven be specified with a heating element to warm an
An air curtain supplying a high-velocity sheet of airenclosed area.
across a door opening will prevent flies and other flyingAir curtains block the flow
insects from entering a building. This is particularlyAn air curtain simply creates a block in the air flow
important in restaurants and bars, and any premisesthrough an opening. The air velocity of the curtain must
where food is manufactured or served - where strictthen be great enough to direct the resulting velocity
environmental health regulations apply. It is andownward and ensure that a small part of the air
extremely beneficial side effect as an air curtain isstream goes out while the main air flow comes back
primarily employed for climate control yet units are alsointo the room.
installed overseas for insect control alone.