Common Questions
Does tunnel fan placement affect wall to wall air velocity distribution?
Not really. You could install tunnel fans in just one side wall (near the end wall) and the air velocity would remain fairly uniform from wall to wall.
Does installing tunnel fans in the end wall as opposed to the side walls increase air speed in tunnel houses?
No. There is essentially no diffference in air moving capacity of tunnel fans whether they are installed in the end wall or side wall.
Can I use my evaporative cooling pads at night?
For the most part no. But during periods of extreme heat where nighttime temperatures are in the mid to high eighties it is possible to use evaporative cooling pads late into the night.
Should I operate all my tunnel fans before using my evaporative cooling pads?
To obtain maximum bird cooling all the tunnel fans should operate before the evaporative cooling system operates. This is because evaporative cooling by itself does not cool the birds as much as many think. Evaporative cooling increases humidity which increases the effective temperature. For instance, for a 5 broliler (at 77F) increasing the relative humidity from 50 to 70% feels roughly the same as increasing the air temperature 9F to 86F.
How do I select the best tunnel fan for my house?
There are basically three performance characteristics you need to evaluate when comparing tunnel fans: air flow ratio, energy efficiency rating, and air moving capacity at the proper design static pressure. The fan air flow ratio indicates how well it will hold up under a static pressure (0.76 or better), The fan should have an energy efficiency rating of 20.8 cfm/watt or better. How many tunnel fans a house rquires should be based on their air moving capacity of 0.10" for most houses. For houses with airspeeds of 600 ft/min, 0.15" and over 700 ft/min 0.20".
How much water does it take for each pound a broiler grows?
From the day they are placed until the day they are sold a broiler will drink approximately a quart of water every pound of feed consumed. If an average life time feed conversion of 1.75 is assumed, this means that it takes a little less than a half of a gallon of water for every pound of bird grown
Does water temperature affect the amount of cooling produced my an evaporative cooling pad system?
In short, “no”. The truth is that the cooling produced by an evaporative cooling system is due almost totally to the evaporation of water into the air and has very little to do with the actual temperature of the water being evaporated. Hot water, cold water, lukewarm water, simply doesn’t matter. The laws of physics say it takes 8,340 Btu’s to evaporate one gallon of water. So, when we evaporate a gallon of water into the air coming into a poultry house using either pads or fogging nozzles, 8,340 Btu’s of energy in the form of heat is removed from the air which results in a decrease in air temperature. How much cooling will the evaporation of one gallon of water produce? It depends on the volume of air the gallon of water is being evaporated into; more air less cooling, less air more cooling. But, for example, if we evaporated one gallon of water into 100,000 cubic feet of air each minute, we would reduce the temperature of the air by approximately five degrees. What role does water temperature play in cooling? Again, the laws of physics say 8.34 Btu’s of energy are required to raise the temperature of one gallon of water one degree. So, if in the example above instead of evaporating, lets say, 70oF water, we evaporated 60oF water, the cooler water would increase the amount of heat removed from the air by 83.4 Btu’s (10oF X 8.34 Btu’s). What does this all add up to? If it was 90oF outside and we evaporated one gallon of water into 100,000 cfm we would drop the incoming air temperature to 85oF. If the water was 10oF cooler, the incoming air temperature would drop an additional 0.05oF to 84.95oF.
Do they make plastic evaporative cooling pads for poultry houses?
Yes. Though not very common there are plastic evaporative cooling pads. In general, they tend to produce less cooling than traditional evaportative cooling pads because they can be fairly difficult to throughly wet. Paper pads tend to wick water so that if the distribution system is not working optimally the enter pad will still tend to get wet. The same doesn't hold true for plastic pad systems. We will be testing a house with plastic pads this summer and will let you know what we find.
Do dimmers reduce incandescent light bulb power usage?
Yes. Basically they will reduce power usage approximately half the amount the bulbs are dimmed (i.e. 50% dim, results in a 25% power savings)
How do I determine which tunnel fan I should install?
Each year we publish a list of the top performing tunnel fans on the market.
