# Windshield Wind Chill?

**URL:** <https://boards.straightdope.com/t/windshield-wind-chill/149865>\
**Category:** Factual Questions\
**Created:** [January 20, 2003, 9:16pm UTC](https://boards.straightdope.com/t/windshield-wind-chill/149865 "2003-01-20T21:16:44Z")\
**Posts on this page:** 3\
**Page:** 2

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**Author:** ![Una\_Persson](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/una_persson/32/346_2.png) [@Una\_Persson](https://boards.straightdope.com/u/Una_Persson)\
**Post date:** [January 22, 2003, 3:56am UTC](https://boards.straightdope.com/t/windshield-wind-chill/149865/21 "2003-01-22T03:56:33Z")

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> [@](#):
>
> \*Originally posted by yojimboguy \*  
> \*\*What? Cooling is NOT heat transfer? I’m no physicist, but I think you’re wrong. Perhaps you can clarify this. \*\*

I think you need to re-examine exactly what I said, because I most certainly did not say that. True, I am splitting hairs, but it’s something I care about. I did not say that _cooling_ was not heat transfer. In fact, I said:

> [@](#):
>
> Evaporation is a form of cooling, not a form of heat transfer. One of the key differences is that there is a mass transfer in evaporation.

Evaporation is a _form_ of convective cooling that _employs convective heat transfer_, but is not the pure form of the heat transfer itself.

From “Fundamentals of Heat and Mass Transfer”, 3rd Edition, Incorpera and DeWitt, pg 8:

> [@](#):
>
> However, there are convection processes for which there is, in addition, a latent heat exchange. This latent heat exchange is generally associated with a phase change between the liquid and the vapor states.

What I am saying is that evaporation is a form of “Cooling” which employs convection as its method. It is not _the form_ of heat transfer itself, which is convection.

The modes of heat transfer - conduction, convection, and radiation - are pure forms of heat transfer, because they do not involve mass transfer out of and away from the system. However, just like you can do so to play games with reversing entropy production, if you draw your control volume the right way you can consider it to be similar to a form of heat transfer. But it’s not the same.

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**Author:** ![micco](https://avatars.discourse-cdn.com/v4/letter/m/5f8ce5/32.png) [@micco](https://boards.straightdope.com/u/micco)\
**Post date:** [January 22, 2003, 3:23pm UTC](https://boards.straightdope.com/t/windshield-wind-chill/149865/22 "2003-01-22T15:23:12Z")

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> [@](#):
>
> \*Originally posted by Anthracite \*  
> **Incorpera and DeWitt**

Arrghhh… freshman flashback… must… not… think…

> [@](#):
>
> \*\*The modes of heat transfer - conduction, convection, and radiation - are pure forms of heat transfer, because they do not involve mass transfer out of and away from the system. However, just like you can do so to play games with reversing entropy production, if you draw your control volume the right way you can consider it to be similar to a form of heat transfer. But it’s not the same. \*\*

This is the point I was trying to make, but you make it much better. Maybe it’s been too long since I was cozy with I&DW.

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**Author:** ![Una\_Persson](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/una_persson/32/346_2.png) [@Una\_Persson](https://boards.straightdope.com/u/Una_Persson)\
**Post date:** [January 25, 2003, 12:14pm UTC](https://boards.straightdope.com/t/windshield-wind-chill/149865/23 "2003-01-25T12:14:37Z")

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So, Jinx, yojimboguy - is that it then? If you still think I’m incorrect, at least show the common courtesy of explaining to me why I am, so I can understand better what you’re asserting. Or am I correct in what I said?

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