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Duct Cooler Placement Guide

A duct is a layout decision, not an accessory

Walk into a hall where somebody bought a duct cooler and skipped the duct thinking, and you will see the mistake before anyone explains it: a unit parked by the door, blowing cooled air down a corridor nobody works in, while the people thirty metres away sweat. The cooler was never the problem. The layout was. A duct does one simple thing that changes everything — it lets the unit stand in one place and the cooled air arrive in another. So the unit goes where intake air, water, power and floor space are easy, and the air goes where people or animals actually are. Take the duct away and both jobs must happen in the same spot. Most halls refuse that bargain. The good intake is by the door. The people are far away. Without a duct, something loses, and it is usually the people.

Routing: the three questions

I route a duct the way I would walk the site, and I ask the questions in the order I meet them. First stop, the intake: is this the coolest, cleanest air the site can offer, or is the unit about to spend its life breathing hot wall air and yard dust? Second stop, the path: can a duct reach the occupied zone without sharp bends, without a marathon run, without crossing a forklift route? Bends eat airflow. Metres eat airflow. Traffic eats ducts. Third stop, the way out: evaporative cooling pushes air into the building, so doors, exhaust fans or roof openings have to be big enough for everything coming in. Plenty of layouts answer the first two questions beautifully and forget the third. The building then tells you about it, in humidity, and nobody enjoys that conversation.

One unit, one zone

Here is the mistake I see most: one unit for a whole hall. On paper a 30000 cubic metre per hour unit looks hall-sized. In the hall it is one discharge point, and one discharge point has exactly one favourite spot. Everywhere else gets the leftovers. Cut the hall the way people actually use it instead — bays where they work, a line where they pack — and give each zone its own unit or its own duct branch. The rest of the volume still gets air exchange as a side effect, which is usually all it needed. Two 18000 units on two real zones beat one 30000 unit on the middle of nowhere, and the reason is embarrassingly simple: light works the same way. Two lamps where you read beat one brighter lamp in the wrong corner.

Water, power and floor, in that order

Before a single line of duct gets drawn, go and stand where the unit will stand, and check three things with your own eyes. Water first — duct units drink 10 to 25 litres per hour depending on size, out of a 300-litre tank, so somebody has to walk a refill route, and that route deserves as much thought as the duct route. Power second, and it has to exist right there, not elsewhere in the building: 380 volts on standard versions, 220 volts on BP versions, 50 hertz. Floor third: the 30000 unit measures 1260 by 1260 by 2300 millimetres, and it wants that space plus room to work around it, not a corner it barely fits. Control, while you are standing there: manual versions run a single speed, BP versions give twelve through the LCD. A route drawn for a unit that cannot be watered, powered, controlled or reached is not a plan. It is a sketch someone will have to redraw on site.

The checklist to send with your inquiry

Want a quote that is not a guess? Send five things and watch the quality of the answer change: how big the zone is and how high the ceiling runs, what throws heat in the zone, where you picture the intake, how the air gets out again, and what voltage waits at the unit's position. A supplier with those five lays out zones and duct routes. A supplier without them counts units from airflow alone — and that count gets installed, right or wrong. Remember what you are actually buying. The duct is not the accessory. The layout is the purchase. The unit just fills it.

A worked layout, without invented numbers

Suppose a workshop with two working bays and a packing line, three zones under one roof. Forget the big unit in the middle — that cools the middle, and nobody works in the middle. Give each zone its own duct unit instead, routes short, clear of traffic, intakes on the coolest side, exhaust through doors or exhaust fans sized for the air coming in. Which size goes where? Follow the zones, not the hall. The hot bay earns the larger unit. The packing line earns the unit whose duct reaches the line without a forklift route in the way. The bay that only needs air exchange earns the smaller one. You will notice no coverage figure anywhere in that paragraph, and that is deliberate: coverage leans on height, heat and openings that only your building knows. The method is the claim — zones first, units second, duct routes third, exhaust always. A supplier who works your hall that way, zone by zone, is doing the job. A supplier who quotes from floor area alone is guessing, and guesses get installed.

Duct joints, supports and cleaning access

Ask an installer to show you three things on the drawing before anyone lifts a tool, and you will learn most of what you need to know about the job. Joints: are they sealed? A leaking joint does not merely waste air — it delivers that air to the wrong place, usually the roof void, where nobody benefits and nobody notices for months. Supports: does the run hold its shape? A sagging duct collects water, narrows the airflow, and fails at the joint sooner than a supported one. Cleaning access: can anyone actually open the run and clean it? A duct nobody can clean keeps everything the intake air carried, and air from the end of a dirty duct is worse than the air that went in. None of this needs a product specification. It needs a walk of the route, a support plan, and an access point marked before installation. A drawing with no joints, no supports and no access points is not a duct layout. It is a line on a page, and lines on pages do not cool halls.

When the duct run is long

Every long duct run starts with the same tempting idea: one large unit at one end, one long route to the zone, job done. It fails in two places, and both hurt at the zone. Airflow bleeds away at every bend and every metre, so the air that finally arrives is weaker than the table promised — the table never met your bends. And the whole zone hangs on one route: one damaged section, one leaking joint, one sagging span, and cooling stops everywhere that route served. Usually the honest answer for a distant zone is a second, smaller unit parked near the work, or the zone re-drawn so the unit sits closer to it. More metal, less disappointment. So when a supplier sketches a long run, press on two points: what airflow genuinely arrives at the discharge, and what happens to the zone when one section fails? If either answer goes vague, the run is too long — and the layout needs rethinking, not the unit.

Facts used here come from the manufacturer's own product pages for the DH-ASY duct series. No airflow loss, coverage area, or temperature figure appears here that those pages do not state — duct losses depend on your route, your bends, and your installation, and they belong in a project calculation, not a general article.