Views: 0 Author: Site Editor Publish Time: 2026-08-17 Origin: Site
Summer heat can turn into a real problem in a poultry house faster than many people expect. Birds eat less, growth becomes less even, and mortality can rise when the house stays too hot for too long. A poultry house cooling pad can help, but only when it works with the rest of the ventilation system.
The pad, exhaust fans, water flow, and house layout all affect one another. If the pad area is too small, airflow can become restricted. If water distribution is uneven, hot air can slip through dry sections. If the local climate is already very humid, adding more moisture may not give the cooling effect the farm expected.
So this is not really about choosing the thickest pad or the largest wall. The better approach is to look at the fan capacity first, then the pad geometry, water system, and maintenance conditions. That gives you a much more useful starting point for a poultry cooling project.
7090 cooling pads are commonly used in poultry houses because they provide a useful balance between airflow and wet surface area.
The size of the cooling pad wall should match the working airflow of the tunnel fans, not a rough guess based only on house length.
A poultry ventilation system also depends on even water distribution. Dry sections and flooded sections can both reduce cooling performance.
Water quality and routine drying have a big effect on how quickly pads become blocked, soft, or covered with algae.
Before picking a pad size, it helps to be clear about what the cooling system is supposed to do. Farm evaporative cooling does more than add moisture to incoming air. It has to lower air temperature without creating another problem inside the house.
A poultry house cooling system is usually judged by more than one number. Temperature matters, of course. Humidity matters too. Air speed through the house also matters because birds rely on moving air to lose body heat.
On a hot, dry afternoon, evaporative cooling can produce a noticeable temperature drop. On a humid day, the same system may do much less. That is normal. The amount of cooling available depends heavily on the difference between dry-bulb and wet-bulb temperature.
This is one reason chasing a fixed temperature drop can cause trouble. If outside humidity is already high, running more water does not automatically mean more useful cooling. Sometimes it only raises the moisture level inside the house.
Cooling pads sit directly in the airflow path, so they create resistance. The fans have to pull air through wet corrugated media before that air can enter the house.
A thicker or more restrictive pad can increase static pressure. Once that happens, the fans may move less air than their free-air rating suggests. The important number is the fan's airflow at the pressure it will actually see during operation.
This becomes especially important in tunnel houses. A cooling system may appear large enough on paper, but if the pad wall creates too much resistance, air speed through the house can still fall below the expected level.
Evaporative cooling works best when the outside air is hot and relatively dry. The drier the air, the more moisture it can absorb from the pad surface. That evaporation removes heat.
High humidity changes the picture. When the air is already holding a lot of moisture, there is less room for additional evaporation. The cooling effect becomes smaller even if the pads are completely wet.
One common mistake: keeping the pumps running harder on a humid day because the temperature is not falling enough. More water is not always the answer. It can leave the house more humid without solving the heat problem.
Two cooling pads can look similar from a distance and still behave differently once air and water start moving through them. Flute pattern, thickness, paper strength, and resin treatment all affect how the pad performs over time.
The 7090 cooling pad is widely used in poultry ventilation. Its flute geometry is designed to give water a clear path downward while still leaving enough open space for air.
That balance is useful in a poultry house. The pad has to stay wet enough for evaporation, but it cannot choke the airflow coming from the tunnel fans.
A 5090 pad uses a different internal geometry and creates a denser airflow path. That can make sense in other evaporative cooling applications, but poultry houses often favor the more open 7090 structure where high ventilation volume is important.
The model number alone should not be the only thing checked. Pad thickness, actual fan pressure, water flow, and house design still affect the final result.
Thickness changes both cooling performance and airflow resistance. Four-inch and six-inch media are both used, but they do not operate in exactly the same way.
Four-inch media: This thinner profile is often used where lower face velocity is expected. It may suit smaller houses, older systems, or climates where peak cooling demand is not as severe.
Six-inch media: The extra depth gives incoming air more time in contact with the wet surface. It is common in commercial poultry houses where higher airflow and stronger summer cooling are needed.
Cooling Media Thickness Comparison
Specification Feature | Four-Inch Profile | Six-Inch Profile |
|---|---|---|
Target Face Velocity | Around 250 FPM | Around 350 - 400 FPM |
Cooling Efficiency | Moderate | Generally higher with suitable airflow |
Static Pressure | Usually lower | Usually higher |
Typical Use | Moderate climates and lower-airflow systems | Commercial poultry houses with higher cooling demand |
Cooling media spends a lot of its life wet, so weak paper does not stay weak for long. Poorly treated sheets may soften, sag, or lose their flute shape. Once that happens, airflow becomes uneven.
Resin treatment helps the paper keep its shape through repeated wet and dry cycles. Buyers should look at the pad surface, flute consistency, bonding, and edge condition rather than judging quality only by color.
Edge coatings can also be useful. They give exposed sections more protection during handling and cleaning. On a farm, the outer face takes plenty of abuse from dust, water, equipment, and everyday maintenance.
The cooling pad wall needs enough surface area for the amount of air the fans are trying to pull through it. This is where a simple calculation is much more useful than estimating by eye.
Total operating fan CFM ÷ target pad face velocity = required pad area
The idea is straightforward. If more air needs to pass through the pad, you need more pad area unless the design allows a higher face velocity.
Add the airflow of the tunnel fans that will operate together during peak ventilation.
Use the fan airflow at the expected static pressure, not only the maximum free-air number.
Choose a face velocity that matches the pad thickness and system design.
Divide the required pad area by the planned pad height to estimate how much wall length is needed.
This gives you a starting point. The final design still needs to fit the actual house dimensions, fan arrangement, inlets, and water distribution system.
If the pad area is too small: Air has to move through the media faster. That can raise resistance and increase the chance of water carryover. The fans may also move less total air than expected.
The house may then have two problems at once: less ventilation and more moisture. In poultry buildings, that can show up as wet litter, poor air quality, and uneven cooling along the house.
If the pad wall is much larger than needed: The problem is different. Air velocity across the media may become lower than intended, and water distribution becomes harder to keep even over a larger surface. There is also the obvious cost of buying and installing more media than the system really needs.
A little design margin is normal. The goal is simply to avoid solving every airflow concern by adding more pad area.
The pad cannot cool much if the water system leaves half of it dry. A working poultry ventilation system needs water to reach the media evenly from one end of the wall to the other.
The pump has to move enough water to wet the whole pad face. Too little flow can leave pale, dry streaks running down the media. Air will naturally take the easier path through those sections, so part of the incoming air enters without much cooling.
Using a larger pump does not automatically fix things either. The distribution pipe, return system, and sump still need to handle that water. Pump sizing should follow the length of the pad wall and the design of the distribution system.
The pipe above the pad usually has a row of openings that release water across the top. If a few holes become clogged, the problem often appears farther down as dry vertical sections.
Deflectors or distribution covers help spread the water instead of letting narrow jets hit only one spot. This sounds like a small detail, but the top of the pad is where even water distribution begins.
Some systems use open return gutters because they are easy to inspect. Others use more enclosed designs that keep sunlight away from the circulating water. Less sunlight can make algae easier to manage.
The sump also needs enough room for the water returning from the pad. If it is too small, the level can change quickly when pumps start and stop. That can mean spills, pump issues, or a lot of unnecessary topping up.
A cooling system usually works better when fans and pumps are staged instead of being switched on all at once. Ventilation can increase first. Water can come on later as temperature conditions call for it.
That kind of sequence gives the house a smoother transition into evaporative cooling. It also keeps the pads from running just because someone forgot to turn a manual switch back off.
A new cooling wall usually looks great. The real test comes after months of dust, hard water, hot weather, and daily operation. Most pad problems build slowly before they become obvious.
If the farm uses mineral-rich well water, white deposits may start appearing on the pad surface and inside the flutes. Over time, those deposits make the passages narrower and harder for air to move through.
Recirculated water can make the problem worse because evaporation removes water but leaves many dissolved minerals behind. As the same water keeps cycling, the mineral concentration can rise.
A bleed-off system can remove part of that concentrated water and replace it with fresh water. How much bleed-off is needed depends on the local water quality. Farms with hard water usually need to pay much closer attention to this than farms with softer water.
Warm water, sunlight, and a constantly wet surface are pretty good conditions for algae. Once it spreads through the pad, airflow and water distribution can both suffer.
Keeping the water system clean and limiting sunlight around the sump can help. Any chemical treatment should also be suitable for the pad material. Strong cleaners may damage the resin or paper if they are used at the wrong concentration.
Worth remembering: more chemical is not always better. Cleaning products should be chosen around the cooling media and water system instead of treated like ordinary household cleaning.
Cooling pads do not need to stay wet around the clock. Letting them dry regularly helps slow algae growth and keeps the paper from sitting in warm water for unnecessary hours.
Many farms shut the water off while ventilation continues for a while. The moving air pulls moisture out of the media and helps the pad dry more evenly.
The timing will depend on weather and flock conditions. The useful idea is the drying cycle itself. A pad that stays wet day and night usually needs more attention than one that gets a chance to dry between cooling periods.
A poultry cooling pad should not be chosen on thickness alone. Start with the tunnel fans and the airflow they actually produce. Then work backward to the pad area and face velocity.
For many commercial poultry houses, 7090 media and a six-inch profile are familiar choices. That does not mean every farm needs the same setup. Climate, house size, existing fans, water quality, and available wall space can change the answer.
Water deserves just as much attention as the pad. A good media wall with poor distribution will still develop dry streaks. Hard water can slowly close the flutes. A dirty sump can turn into an algae problem before anyone notices much change in house temperature.
When comparing suppliers, look at the whole system. Check the paper, resin treatment, edge condition, dimensions, water distribution parts, and how the pad will connect to the existing ventilation setup. That usually tells you more than a single cooling-efficiency number.
A: There is no fixed number that works for every farm. Water quality can change the answer a lot. So can cleaning, drying, dust levels, and how many hours the system runs each summer. Resin-treated pads that stay clean and keep their flute shape will usually last much longer than pads covered in mineral scale or algae.
A: Look at the pad before looking at the calendar. Sagging sections, crushed flutes, soft lower edges, heavy scale, and large areas that no longer wet evenly are all signs to pay attention to. Airflow can tell you something too. If the house is harder to ventilate even after the pads have been cleaned, the media may be reaching the end of its useful life.
A: Sometimes there is little reason to. Outside temperature often falls at night while humidity rises, so the benefit from evaporative cooling can shrink. There are exceptions, though. A very hot night or a specific flock condition may change how the controller is set. It makes more sense to respond to temperature and humidity than to use the clock alone.
A: The two designs use different internal flute geometry. A 7090 pad leaves a more open airflow path and is widely used in poultry and agricultural ventilation. A 5090 pad has a denser structure. That changes both air resistance and how air contacts the wet surface. Which one fits better depends on the fan system and the application rather than the model number by itself.
