Temperature with wind chill?

Jared

Member
I have a math problem I am hoping someone can help me with. As we battle the temperatures and still need to get to job sites as early as possible I need to know more accurately when our rigs can hit the road. If I am driving 60 miles per hour how many degrees does that influence the atmospheric temperature for my exposed rig? If it is 32* when we pull out of the garages and drive 60 mph down the road the rig is actually how cold? Some jobs are an hour away so assume all residual heat is lost from garaging the unit.For all the math guys, Thanks!
 
I am waiting to see the answer on this question.

I have a weather station that records wind chill and wind speeds, and it is interesting to watch.


Here is my thoughts on it. I could be wrong but here goes.

If the outside temp is 30* and you drive 60mph, the temp is still 30*.

Wind chill is only a term used to describe how it feels to us as humans.

Now with that being said, if your rig was sitting outside overnight and it was 30*, there is a chance that it may not have froze up, but I gaurantee if you drove for one hour at 60mph in 30* it would be froze up, because the wind force the cold air into the machine. Not only is the surface 30* now but the wind forced the cold into the core of the machine.

Does that make sense, or am I all wet and freezing up?? :)
 
Jay, you are correct. Wind chill is basically the level at which the ambient temperature is reached. With a wind chill of 32, it will reach 32 slower than a wind chill of 10, but it still only gets to 32.
 
Russ J did not realize this post took an hour to compose (along with some interruptions), you had not posted when I started this, lol

Not a thermodynamics major, here is my contribution:

The gradient of temperature change is form high to low, so if the rig is warmer than the outside air temp it would loose heat (its warmth) to the atmosphere, until the current atmospheric condition (temperature) is attained. The wind factor affects the rate at which the heat (warmth) is lost.(the wind factor could cause freeze if current atmospheric conditions are 32F or below, let me explain)

"water freezes at 32F", thats a generic statement that we all use, but at 32F you could have a container of all water, or a combination of water and ice, or ice only. What determines the state or combination of states is the loss of waters latent heat, this is a heat loss that occurs without a change in temperature, and could bring the "pure water" to all ice at 32F.

Notice I mentioned "pure water", impurities in water (minerals, additives) affect the freezing point. Example,.. table salt will lower the freezing point, meaning the solution will freeze at a temp below 32F, at what temp?..... that depends on solution concentration (amount of salt in solution) anywhere from around 32F to 0.0F

All that being said,So if the air temp is below 32F with or without 60mph wind the water will freeze, what we dont know is the rate at which it will.(and I guess that what you are asking)

if temp is at 32F at 60mph it would freeze too, a little slower

Above 32F it would not freeze even at 120mph.

The reality is a lot of factors affect the answer, inlet water temp, the coil temp at drive start, the type and quantity of impurities in the water, the quantity of water, the coil insulation, machine insulation, etc

In my opinion, one hour drive time at 60 mph, even at 32 deg, would not freeze the system to cause damage, some components however may be frozen.... (exposed connections with little water).

You could fire up the rigs (3 mins) and attain working temps throughout the system for more safeguard, of course antifreeze of removing the water would be best.
 
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If the temprature is 32 degrees out and you drive 448 mph down the road the temprature is still 32 degrees.
Wind chill is what the temprature will FEEL LIKE to a person based on moisture content and wind speed.
 
While wind chill may be a measurement for people - and I don't know how its calculated - moving air will expose 'more' cold air to the surfaces and increase the rate of heat loss for sure. I think it needs to be tested and not calculated. I have had stuff freeze up on short drives here when its below 30 deg, think the humidity affects it also.
 
Excellent replies. Thank you.

I wasn't aware that wind chill for the sake of temperature impact was really only for people and not inanimate objects. The Nat'l Weather service chart put the wind chill of 60 mph wind with 32 degree atmospheric temperature at 13* F. If I am understanding everything correctly, the wind doesn't affect the machine other than quicker heat loss through transfer, wind doesn't drop the water temperature in the system below the atmospheric temperature.?
 
I remember arguing with a kid in high school. He said that it could be 60 degrees and u could have freezing rain as long as the wind chill was below freezing. I said uh no stupid, let's go ask the science teacher. The teacher agreed with him!
 
I remember arguing with a kid in high school. He said that it could be 60 degrees and u could have freezing rain as long as the wind chill was below freezing. I said uh no stupid, let's go ask the science teacher. The teacher agreed with him!

I've seen sleet in the 40's. The air temp is colder higher in the atmosphere were it can freeze and not melt before it hits the ground.

Back to the question at hand- I can't tell you in math but run a gallon of washer fluid through the coil and everything else and you will be fine at 32. I have a washer exposed that frequently leaves the shop and works all day long down to about 15. good luck
 
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