Solar Heater ?

[kevincad]

I have a south facing roof, in the Atlanta, GA area, that gets about half the sun during the day due to tree shade. With this half of the available sun for the day, will it be effective? My pool gets some shade, so it doesn't get quite warm enough, I'd like to raise and keep the temp. about 5 degrees or a little more, 13.5k gallon above ground pool. I thought about a natural gas heater, like 100k btu, but no one has ever given me even a ball park est. of what it would cost to raise and keep the temp. 5 degrees with it!! But, if I can keep the temp. that 5 degrees with solar, then that's the way to go. Now, if I do that, from where the pool is, is actually three stories high. How does the water get up there? Do I need a seperate pump? If so, how does that work? Would the pump be regulated by the water temp, or does it just run water through it constantly? Thanks.

[mas985]

If you are the least bit science minded, here is a bit of software you can use to determine heat gain for a solar pool. It will also perform the economics and compare solar only to solar and heater or heater only.

http://www.canren.gc.ca/tech_appl/in...aId=5&PgID=484

[Poconos]

Whether you go for some temperature control or not depends on how complex you want to get. Generally the flow is continuous. In my situation I manually close the solar valves on cool sunless days. Anyhow, I suspect the pump output when directed totally to the solar 3 stories (30') up would be enough to purge the system of air. Once you get a solid charge of water the effort needed for circulation is about the normal flow resistance. Water weight on the downside is equal to that on the upside. However...I'd be a little concerned when the pump is shut off. I forget a lot of the physics but I believe 32' is all you can raise a column of water with a vacuum. Beyond that the vacuum created will cause the water to boil. You have reduced the boiling point to ambient temperature by pulling the vacuum, or in this case just the weight of a 30' column of water. What happens then is with the pump off you may get a water vapor bubble at the top of the system. If full pump output is to the heater then no problem. However, if you divert only partial pump output to solar, after you've initially purged the solar heaters of air, then there may not be enough pump pressure in the solar loop to purge the water vapor bubble. Not really sure about all this and welcome anyone else to correct me or add to what I've said. In my years on the forum I can't remember anyone trying a heater 30' up.
Good Luck.
Al

[kevincad]

Whether you go for some temperature control or not depends on how complex you want to get. Generally the flow is continuous. In my situation I manually close the solar valves on cool sunless days. Anyhow, I suspect the pump output when directed totally to the solar 3 stories (30') up would be enough to purge the system of air. Once you get a solid charge of water the effort needed for circulation is about the normal flow resistance. Water weight on the downside is equal to that on the upside. However...I'd be a little concerned when the pump is shut off. I forget a lot of the physics but I believe 32' is all you can raise a column of water with a vacuum. Beyond that the vacuum created will cause the water to boil. You have reduced the boiling point to ambient temperature by pulling the vacuum, or in this case just the weight of a 30' column of water. What happens then is with the pump off you may get a water vapor bubble at the top of the system. If full pump output is to the heater then no problem. However, if you divert only partial pump output to solar, after you've initially purged the solar heaters of air, then there may not be enough pump pressure in the solar loop to purge the water vapor bubble. Not really sure about all this and welcome anyone else to correct me or add to what I've said. In my years on the forum I can't remember anyone trying a heater 30' up.
Good Luck.
Al

Another scenario that just may work, is if I can put the panel on the side of the house. It would be hidden from street view by my chimney, but I'd have to mount it vertically, meaning the long dimension vertical, the short dimension horizontal. Do you know if that can be done, and will it operate efficiently like that? Thanks

[Poconos]

Shouldn't be any problem mounting it vertically. Turn your pool into a science project and have fun. Whatever you do please keep us posted. Real life information is always welcome.
Al

[kevincad]

Shouldn't be any problem mounting it vertically. Turn your pool into a science project and have fun. Whatever you do please keep us posted. Real life information is always welcome.
Al

I'll do that. Albeit it may turn into an expensive experiment, as is my usual! I really only need to raise the temp 5 degrees, or at most 10 a few weeks. My pool is 13,500 gallons, and I think it wouldn't take to much solar power to do that, if those kits work half way decent.

[kevincad]

Thanks! I am scientific minded....engineering career!