Fan Cooling Power

No. Discounting radiation and conduction, you are left with convection. So, this means that any heat that is carried away must be transferred by the air molecules passing over the part.

Once the part and the air are at the same temperature there is no potential for energy transfer. The part can't get any cooler.

As to the apparent temperature difference front to back of the fan, without seeing the setup, that's anybodies guess.

Significant cooling cannot occur from just the movement of air by a fan. Now a fan can increase the cooling effect from evaporation or could improve part of a system that uses compression and expansion to transfer heat. I suspect that you're actually getting a false reading by using an infrared pyrometer that is actually showing you the heat generated by the motor on the air intake side of the fan and not the air entering the fan.

GA. The IR gun I've used says if you're not sure of the emissivity of the surface place a piece of ordinary masking tape on the surface. It will take on the temp of the surface and it's emissivity is close to the value used for calibrating the IR gun.

Thanks everyone for your reply. My question stems from someone who told me the coolers at my work where freezing due to wind blowing over them.Supercooling them and dropping there temp more them ambient air.

Or, The "coolers' were cold enough to freeze water out of the air.

You have completely changed the thrust of the whole issue.

Could you perhaps give us the entire picture at one time?

The coolers are outside the plant at ground level and they are pitched for draining. The water is inclosed in tubes that keep cracking. This happens when it gets in the teens outside southern Wisconsin. I do understand the the rate of chilling would be faster but, how fast?

This sounds like a cooling tower, as water is involved. The entering air is at dry-bulb temperature; the leaving air is at slightly above wet-bulb temperature.

Lack of info stumps me. Thought out the effects of icing on aircraft but have never heard of icing on a propeller. My employees work on refrigeration every day of the week and have never hade ice on fan blades. would love to see a GA on this one.

" icing on aircraft but have never heard of icing on a propeller."

Haven't been around too many aircraft? Props can, and do, ice if conditions are right.

Not to be too critical, but, "He who can no longer pause to wonder and stand ramt in awe, is as good as dead;his eyes are closed."

Don't you mean, "He who can no longer pause to wonder and stand rapt in awe, is as good as dead;his eyes are closed."

I give up on the, " can a fan cool a steel part cooler then ambient air in the room"

problem.

Bye.

Would like to help, but there is not enough information to go on, as it sounds like you have an ordinary chiller, ie refrigerating unit that is probably connected to a set of heat exchangers, as this does not make sense to have frozen part when the ambient is in the teens with an ordinary water tower. if you can describe what the system is for and what the overall system looks like. or throw us some names and model numbers or photo would be better.

The 'teens' are degrees F I believe.

It is not possible to cool a part below ambient temperature without using another fluid.

The principle that a water/air cooling tower uses is the evaporation of the water, which will cool it to the wet-bulb temperature of the surrounding air, which varies with altitude, pressure, weather conditions and time of day. Most of the time, the wet-bulb is lower than the dry bulb temperature; that would do it.

If a temperature is required that is lower than the current wet-bulb, a fridge system must be employed to create a chilled service fluid. The part is then immersed partly or fully in the chilled fluid; that would do it.

Fully agree with you.

This application is not suitable to be cooled by a FAN. We can suggest many alternates if that is what u are looking for. Please let us know.

I don't believe he's talking about an actual fan. He is talking about the outdoors wind blowing across it, cooling it more than the temperature outside... but was using the fan explanation to decribe the theory in a round about way.

Am I deciphering this question properly??

Yes,that's what I was trying to say maybe I should have been more clear about it. I am new to this kind of form but, thanks for all the replies.

Once again, if water is present, either a fan or the wind can result in cooling to (or at least near) the wet-bulb temperature, which will be less than the ambient temperature unless the air is saturated with water vapor.

Dear Watts up,

NO is the answer.

DHAYANANDHAN.S, INDIA