Re: [DML] Re: What temperature should AC be on normal setting?

[Paul Gress <pgress@xxxxxxxxxxxxx>]

On 07/27/12 02:51 AM, Martin Gutkowski wrote:
> Paul is correct. If his explanation is unclear, take it to the extreme. Turn the air flow down to zero. Is it still transferring all that energy? No. HOWEVER, is there a point when increasing speed beyond which it makes a negligible difference? Yes. Turn it down a bit from there and it will make a negligible difference too.
>
>

Yes I agree with this explanation.

To take it to another extreme, almost using Bills terminology, If I hold a red hot poke and place it in a thermos bottle and close the cap, the red hot poke will heat up the air temperature very fast, then stop when it hits almost equilibrium (extremely small delta t), basically the red hot poke wont loose much temperature.  Now if you were to open the thermos bottle, allowing cooler air to migrate over the red hot poke, it will cool down even more.  If you were to open both ends and blow air through the thermos bottle the red hot poke will cool very rapidly.  This is the measure of heat transfer.  If you were to blow the air faster, it should cool down more rapidly, and as Martin explained, with diminishing returns.  The fact that the air temperature in the thermos bottle got hot doesn't prove anything.  The fact that the red hot poke cools down rapidly shows the transfer of BTU's.

Paul


[Non-text portions of this message have been removed]



------------------------------------

To address comments privately to the moderating team, please address:
moderators@xxxxxxxxxxx

For more info on the list, tech articles, cars for sale see www.dmcnews.com

To search the archives or view files, log in at http://groups.yahoo.com/group/dmcnewsYahoo! Groups Links

<*> To visit your group on the web, go to:
    http://groups.yahoo.com/group/dmcnews/

<*> Your email settings:
    Individual Email | Traditional

<*> To change settings online go to:
    http://groups.yahoo.com/group/dmcnews/join
    (Yahoo! ID required)

<*> To change settings via email:
    dmcnews-digest@xxxxxxxxxxxxxxx 
    dmcnews-fullfeatured@xxxxxxxxxxxxxxx

<*> To unsubscribe from this group, send an email to:
    dmcnews-unsubscribe@xxxxxxxxxxxxxxx

<*> Your use of Yahoo! Groups is subject to:
    http://docs.yahoo.com/info/terms/