Water temperature change due to sun light 1

[Robski]

G'day,

I am after a formulae set or model that will calculate the temperature change of a body of water of given dimensions due to the radiant heat transfer from the sun.

I have just installed some cooling towers that output the cooled water into a large storage pond. This pond may be subject to additional warming due to sunlight, particularly in the summer. If this is the case I need to know if I am losing cooling efficiency by the fact that the storage pond water is warmer than the water outflow of the cooling tower. The pond is about 1.5x30x45m in dimension.

Any information would be helpful, anecdotal or otherwise.

 

[ceesjan]

Robski,

calculating the water temperature is not so simple as it seems. Various factors play a role (indeed sunlight, depth of the pond, location etc etc).
If u use the water in your condenser and want to know the temperature of your water you have to measure or use a correction (water temparature will be relatively cooler in the summer and warmer in the winter than the outside temperature) based on measurement data and a local temperature profile.

Cees-Jan

 

[butelja]

Do not forget to include evaporative cooling from the pond as well as the solar heating. Relative humidity, wind speed, and cloudiness will all come into play. At night, radiant cooling will also be a factor. There are so many variables involved, you can likely get just about any temperature you desire just by playing with the input variables to your calculations.

 

[Robski]

Folks,

Thanks for your input.
I thought that this may be the case, I wrote a list of all the possible variables and as you have described, there are so many that can vary from minute to mintute that the average benefit/detriment is very difficult to calculate. The intention is to try and insulate the pond from temperature increase but it would appear this will also insulate it from temperature decrease at night.

If anyone has any further experiences of attempting to achieve this can they let me know. I am more interested in the practical solution than the theory now.

Thanks again.

Rob

 

[butelja]

From a practical standpoint, a deeper pond with less surface area will be less affected than a shallower pond with larger surface area.