Solar installer saying wind is reason for pool not warming

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ThatGrrl

Solar installer saying wind is reason for pool not warming

Postby ThatGrrl » Wed 21 Oct, 2009 23:21

Hey guys,
I am hoping someone that works in the pool industry or knows about solar pipes can help me out here. I recently got solar pipes installed on my roof to heat my pool. The pool company came out and gave me a quote based on measurements taken etc, all was well I went with it and install took place.

Since the install my pool feels ever so slightly warmer, but not warm. By comparison to another pool at another property I own (that is also solar heated with pipes) this pool is cold. Today the installer came out and hits me with "it's the wind and I can't control the wind". He's telling me the wind is blowing across the pipes because I live by a river. The magical wind is also blowing across the pool (which is way above river level) and cooling it also. He's now telling me essentially 'thems the breaks' and the pool won't ever be warm (something he neglected to tell me BEFORE the installation!!! Didn't he notice the gaping great river then!!!).

It's driving me nuts because this guy also talks to me like I am a moron. Surely this isn't true, not to the point he's suggesting? All the houses on my street would therefore have solar that also is not working!! We got the solar for Winter, it is now averaging 28C a day here, if it's not warm in those temperatures what use is it going to be when it's Winter???

Does wind affect it that much or is this dude yanking my chain?? I am assuming it may affect it 'slightly', but not to the extent he's suggesting. He saw the pool and surrounds BEFORE he did the quote obviously, surely he should have mentioned this magical icy wind then? (icy.. it's almost 30 Celsius for goodness sake!).

HELP me Obi Pool Kenobi. :(


chem geek
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Solar installer saying wind is reason for pool not warming

Postby chem geek » Thu 22 Oct, 2009 02:21

Solar panels become less efficient when the temperature difference between the air and the water in the panels is higher. This is especially true for the more common and less expensive "black mat" panels. I have a table showing the drop in efficiency in this link , but if your wind is as warm as you describe then I doubt that it is seriously affecting the ability of the panels to put in warmer water into the pool. You should feel the water at the returns to see if it is noticeably warmer going into the pool.

Now wind can have a serious impact on the rate of evaporation of pool water and that can cool a pool significantly, pretty much wiping out whatever a solar panel was going to do for you. Evaporation is much higher when there is wind and it is also higher when the air is dry (i.e. low relative humidity) and when the water temperature is warmer. A pool cover would significantly help prevent evaporation and therefore retain heat in this case.

Of course, if your panel and pool conditions are similar to neighbors and they aren't having a problem, then something sounds wrong about your particular setup.
ThatGrrl

Solar installer saying wind is reason for pool not warming

Postby ThatGrrl » Thu 22 Oct, 2009 18:41

Hi thanks for the reply...

just to clarify.. the 'panels' are NOT solar, there are no solar panels as such... it is called solar heating but it is actually an array of rubber / plastic black piping that covers a large area of the roof.

The sun heats the water within the pipes and this is pumped into the pool via an electronic box connected to the filter system.

This is where I am highly dubious of what he's telling me... black retains heat, these pipes are heated by direct sunlight. It's meant to pump into the pool until the temp in the pool water hits the desired temp. He told me the pool was 30 degree C on the data box that reads it, I put my hand in and the water was tepid at best (on the surface colder under) NOT 30 degrees which as you can imagine is very warm.

So to clarify, he's telling me the wind blowing across these pipes on the roof is cooling the water. Now most places in Australia use this system and a roof is high so you're going to get wind regardless... the whole thing sounds dodgy to me and that's putting it mildly.

Anyone?
chem geek
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Solar installer saying wind is reason for pool not warming

Postby chem geek » Thu 22 Oct, 2009 21:05

I didn't mean to imply that the panels were solar cells for electricity. By solar panels, I meant black plastic panels for solar heating such as this one (with a cutaway view) from Fafco.

As I wrote, wind will make such solar pool heating systems inefficient and unable to heat if the temperature difference is high between the water and the air. In the example you are giving, it sounds like the air temperature is warm so wind should not negatively affect the solar heating from the panel. However, wind over the pool water can increase evaporation and that can significantly cool the pool water even below the air temperature. This problem is readily solved by use of a pool cover which also helps retain heat at night.

By the way, a properly operating solar black plastic panel will NOT be hot to touch. With sufficient water flow through the panels, they should remain only a few degrees above the water temperature. It is inefficient for them to get hot -- you want the water flow to be fast enough to carry away the absorbed heat as quickly as it is coming in from the sun.

30C is 86F so if it says that on his box measuring your water temperature, then that doesn't sound correct if the water feels cool. You can, of course, take a thermometer to measure the pool temperature -- probably a good idea to have anyway.

See if your particular solar pool heating system is listed here check its efficiency rating.
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Solar installer saying wind is reason for pool not warming

Postby Pool Clown » Fri 23 Oct, 2009 22:51

To add: Keep in mind that the sun is not a the best angle now (fall/winter season) and getting worse every day. As well as less of it per day. Southern hemisphere excluded.

Just a clown talking...ignore him.
Factory warranty service for Pentair, Jandy, Raypak, Polaris, and Paramount pool cleaning systems.
chem geek
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Solar installer saying wind is reason for pool not warming

Postby chem geek » Fri 23 Oct, 2009 23:21

A very good point. Thanks, PoolClown.

ThatGrrl, you said you got the solar for winter, but are you in the southern hemisphere where winter is the hot season? If you are in the northern hemisphere, then a standard inexpensive black flat mat style solar pool heating system isn't going to give you very much heat during the winter in the U.S. unless you are in the southern part such as Florida, Arizona, etc. and assuming there is direct sunlight (i.e. not clouds).

I live in the San Francisco Bay Area and fortunately today was warm enough to have the solar on and heating the pool, but with the cool nights and the low angle of the sun the water can't get very warm, not able to get much above 80F without gas assist. During the regular part of the summer, I'm able to keep the pool at 88F with no problems. This all changed towards the end of September.

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