I'm guessing you only want to heat the pool when the house doesn't need heat. Also is there really a need for a tempering valve on the pool loop?
Sizing would have to be determined by your local solar insolation, and btu's required to heat your house. I believe you'll find information on that at: http://builditsolar.com/ you may find some other ideas that will help there.
You may also consider a separate system for Domestic Hot Water since at times you'd have a usable heat in your tank for interior heating that would be lower than you could use for DHW. That would reduce the energy usage from your backup heating. Also you'll be using that system year round. Consider, interior heating can be used down to 75 (a stretch) which wouldn't be very useful for DHW. Even temperatures as low as 90F wouldn't be of much help (except for pre-heat) in DHW.
Some of your arrows seem to be indicating the wrong flow direction.(bottom for back-up tank, between Dc pump for solar panel and exchanger loop.
I'd also eliminate the float valve for filling your tank and use a manual one and have a way to know what your water height is.
Confused by a few other things,also i see a hot line just dumping into tank from DHW circuit? Or is that a pickup line for your PEX? DO NOT EVER mix an anti-freeze solution and DHW. you cannot even switch lines over..so that one is confusing.
In a nutshell,solar to storage, pex loop uses tank water,DHW would be better off with a separate system (you could use a heat exchanger to add heat to main storage if the DHW has an overabundance)PV for pump power, and determine sizes which without a LOT more info we cannot do for you.
Oh and looking again, why is there an exchanger loop from the solar panel? Aren't you planning to use an antifreeze mix for the storage, PEX loop, and Solar panel water? I'm also not seeing a reason for the dump load under the driveway.
If you used a drainback system for your collectors, you could eliminate the need for anti-freeze, also.
"I'm not really understanding your flow on the pool, but why have separate coils for your PEX heat loop and your pool? you should just use the tank water for the PEX loop.(i may be confused by what you're doing there) Used simultaneously I doubt it would keep up with both loads."
My plan that maybe was not clear on the diagram is to prevent pool water to go into the storage tank because of corrosion issues. That's why I put a separate heat exchanger coil for the pool. I thought it should be made of pex. The need for the tempering valve is because since the system would be sized for winter heating, I think I will have more than plenty heat in the summer. That is also why I planned for a dump load under the drive way. My roof is very high and I will not go on top to cover part of the collectors in the Summer.
A separate system for domestic hot water and heating may be a good idea. I understand here two separate storage tanks but one single set of collectors that would be directed towards domestic hot water in priority. One may be bigger wooden for heating directly used by the radiant heating loops and the other smaller and pressurized for domestic hot water.
I will check the flow directions and post an improved diagram soon.
The float valve for filling the tank was to make the system as maintenance free as possible. I understand if there is a leak somewhere, I need to be advised so things need not be totally automatic.
I plan to use a heat exchanger loop from the solar panels because I didn't want to have such a big amount of concentrated antifreeze. The amount I would put would be just enough to make it less prompt to grow stuff in the water but not as concentrated as in the solar loops. The other reason is that I was told the collectors prefer to have a pressurized system with no oxygen renewal and I would then need a big pump to be able to push 35 feet of fluid up to the collectors. I understand putting concentrated antifreeze would make the system more efficient though: better heat transfer from collectors to storage tank.
I didn't think drain back would be adequate to heat space during winter.
Thanks for your comments
MartinEau, soleil, le vent[ Parent ]
Eliminating exchangers can reduce losses. For instance if you had a heat exchanger on your solar loop, the tank water would not increase as easily as if you used the water directly.
Heat exchangers should be used to separate Domestic Water from any possible contaminated water. In other words, your pool loop, and your DHW loop. Which could be the same if used at differing times.
Oh and using PEX for an exchanger loop is not as efficient as copper. Also when I was speaking of your PEX loop I was speaking of your heating system loop(s). [ Parent ]
I didn't get your point about using the same loop for pool and dhw. I need dhw year round. But that gives me the idea of using
About the pool heat exchangers: wouldn't using copper end up having corrosion and pool water contaminating the tank.
Considering all these nice posts, I will have to reconsider my whole system...
To help describe some things, there are two thermal valves to switch from main storage to Domestic Hot Water exchanger storage. A pv panel to supply power for pumps. A tempering valve to insure no scalding water is present at DHW faucets. A heat exchanger for pool,and one for DHW to insure no contaminants enter the DW supply.
I still prefer drainback for freeze protection , and to make the filling costs cheaper.You'll also notice a pipe(not labeled) between the tanks, this should be slightly above the normal water level, to allow the two tanks to balance their levels..
I also forgot to add a fill and overflow..oops, and didn't label the house heating circuits pump. For simplicity I didn't show any wiring.
You are obviously mis-reading something my suggestion for using 1 heat exchanger was you COULD switch between the house heat circuit and the pool circuit IF you do not require both at the same time. You NEVER (ever) EVER!!!!! mix ANY water (or switch between pipes that use it)that could possibly contain contaminates with your DW system..PERIOD.
System usage: PV runs pump when solar insolation is high enough to use the collectors(it's possible to add a mini-maximizer in that circuit). the system drains back (I neglected to add valves for that) emptying the collectors when not in use. Eliminating the need for anti-freeze. Water is routed to the DHW exchange tank until tank temp is high enough, then switched over to main storage.(or you could have two totally separate systems). Heating is available for pool in summer, and heating the house in winter.
Sizing solar panels the size of the storage tanks,pumps and the heat exchangers depend on your needs,and I'm not going to engineer that part for you.[ Parent ]
Very good idea to separate the dhw from the main heating storage! I will search the board for drainback valves and sizing calculations.
