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15-06-2006, 12:06 AM #1
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rate of evaporation from swim pool surface
Hi guys,
Anyone out there got any links or info from which I can calculate the evaporative rate (mass flow) of water vapour from an indoor swimming pool surface. I can do the building fabric heat gain /Losses etc. but have no info to calculate the dehum duty for heat recovery.
Cheers
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15-06-2006, 02:35 PM #2
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Re: rate of evaporation from swim pool surface
There was a recent article in the ASHRAE Journal some months ago concerning this.
Perhaps you can do some research on their site.
Try this for a starting place...
http://resourcecenter.ashrae.org/sto...e/newstore.cgi
You can purchase these articles for a nominal fee and download it immediately.
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15-06-2006, 07:29 PM #3
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Re: rate of evaporation from swim pool surface
http://www.desert-aire.com/litlibrary.asp
You will find here all whta you need.It's better to keep your mouth shut and give the impression that you're stupid than to open it and remove all doubt.
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15-06-2006, 07:55 PM #4
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Re: rate of evaporation from swim pool surface
Now, there's a handy site Peter, thanks.
Brian - Newton Abbot, Devon, UK
Retired March 2015
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15-06-2006, 07:57 PM #5
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Re: rate of evaporation from swim pool surface
Good link Peter
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15-06-2006, 08:23 PM #6
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Re: rate of evaporation from swim pool surface
I just was preparing an article for the Belgium HVAC/R magazine about dehumidification of swimming pools and used this site as a basis.
It's better to keep your mouth shut and give the impression that you're stupid than to open it and remove all doubt.
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17-06-2006, 01:18 AM #7
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Re: rate of evaporation from swim pool surface
Peter: Many thanks for the info .... very useful
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02-04-2007, 07:35 PM #8
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Re: rate of evaporation from swim pool surface
The problem of evaporation rate from a pool surface is exactly like the problem of heat transfer.
Originally Posted by nevgee
In heat transfer, the unknown quantity is the convection heat transfer coefficient.
In mass transfer it comes down to the mass transfer coefficient, hd.
The relationship for evaporation loss is:
mw = hd A (Wsw - Wa)
mw is the mass flow of water by evaporation, kg/s
Wsw is the humidity ratio of saturated air at the water surface temperature, dimensionless.
Wa is the humidity ratio of the ambient air above the pool surface, dimensionless.
A is the pool surface area, mē
hd is the mass transfer coefficient, (kg/s)/mē
hd can be estimated by using the diffusion coefficient of water in air. My experience with this has not been that successful.
All the other values are well known since they are design values.
hd is another story since it depends on air movement, water turbulence.
I notice that an outdoor pool looses 1000 litres/week at certain ambient conditions. From this, I can easily calculate hd. The simple experiment is worth much more than the theory in this case since it takes account of your system configuration.
