[Equest-users] How do you think about the no electricity Eco-Coolers from Bangladesh

[Joe Huang via Equest-users]

I saw today the same technology also promoted on the CIBSE Bulletin Board even with a 
video "explaining" how it works (the plastic bottles supposedly "compresses and cools the 
air")

( 
https://www.linkedin.com/groups/75555/75555-6160367729091100672?midToken=AQF3zdCi1vKWLA&trk=eml-b2_anet_digest_of_digests-hero-8-view%7Ediscussion&trkEmail=eml-b2_anet_digest_of_digests-hero-8-view%7Ediscussion-null-bc6m0%7Eiqtrhngl%7Eh3 
)

To me, this seems more like wishful thinking.  My comment posted on the CIBSE Bulletin 
Board was:

I don't understand how this would work from a thermodynamic point of view. There has to be 
some air velocity to begin with, in which case I can see how the bottles might channel the 
air flow resulting in higher air velocities coming out of the bottle openings, but 
wouldn't the total amount of air flow be the same, or less than through the window opening 
with no obstruction? Also, someone explain to me how compressing the air will cool it?? 
I've always thought that compressing the air would heat it up, although in this case the 
effect would be extremely minimal either way.

Joe

Joe Huang
White Box Technologies, Inc.
346 Rheem Blvd., Suite 205A
Moraga CA 94556
yjhuang at whiteboxtechnologies.com
http://weather.whiteboxtechnologies.com for simulation-ready weather data
(o) (925)388-0265
(c) (510)928-2683
"building energy simulations at your fingertips"

On 7/14/2016 7:22 PM, 冷面寒枪 via Equest-users wrote:
> Recently,I read the news about the zero air cooler,which is made with re-purposed 
> plastic bottles.And the new claims that it helps reduce indoor temperature by 5 degrees 
> centigrade.
> The making process is shown as following:
> I dout that very much.
> the Joule-Thomson Coefficient for air (mostly nitrogen) at 300K (27°C/80°F) is about 
> 0.36K/bar. This means that at 300K a 1bar change in pressure equates to a 0.22K. The 
> change in pressure required to get the 5°C (5K) reduction would therefore be:
>
> 5 / 0.22 = 22.7bar
> So I think it is impossible the temperature drop will be up to 5  degrees centigrade 
> after the air through the bottle.
> What do you think?
> ------------------
> *Yongqing Zhao*
> *Changsha Green Building & Energy Saving Technology CO.,LTD
> *NO.438,Shaoshan Road,Changsha,Hunan,China
> Telephone:13574805636
> Email:zhaoyongqing1987 at 126.com
> 503271081 at qq.com
>
>
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