The solar heater I'm using can run potable water through the heat exchanger manifold so the tank is way cheaper. I am having to uprate the HW tank to a stainless one as the existing enamel (also called a glass lined) tank is only rated to 80 deg C.
BTW - the tank runs at mains pressure so no header tank (just a pressure release valve or two).
It all gets installed next week :-) Robin - Down Under (or are you Up Over)
SCOTTSAI- i wanted to use the tank because i have a 40gal elec hotwater tank handy. and i want to have a large amout of hot water on tap, thats why i was thinking tank vs coil. i will try and draw up my idea soon.
GARYGARY- the tanks will be plumbed just like my existing hot water tank so there shouldnt be any air in the system. hot water goes out and is replaced with cold well water in.
how many gallons r in 200' of 3/4" pex? im looking to use this system as my only form(could be in dream land)of hot water. so the more hot water i have on tap the better.
the big tank would only be used for hot water. i have a forced air furnace that suplies heat to my house, and i will have the wood furnace added on.
12AX7- thanks for the calculations. i doubt my 1925 basement concrete would be able to hold the weight. so i will have to do coils in a smaller tank or something else..
FRACKERS- my only concern with going all solar is the fact that im in michigan and there are weeks(right now) that are overcast and not much strong sun. if i had the wood furnace making hot water too that would heat my hot water for almost 5 months out of the year. solar should handle the rest.
also the system would have to be a drain back system seeing as we have freezing temps here. [ Parent ]
Volume = (200ft)(0.75^2*0.785 in^2)(12 in/ft)(1 gal/231 in^3) =4.6 gallons
If your concrete sits on dirt, I think that its like OK for the tank loading. The weight per sqft of the tank is about the same as you walking around on the concrete, and as long as there is dirt under it so that all the concrete has to do is pass the tank load through to the dirt, it should be fine. Both of my tanks sit on dirt with rigid foam board insulation between the tank and dirt -- even the rigid foam board holds up to 4 ft of water OK.
I think I would try to get some kind of line on whether that tank is going to last very long when immersed in hot water -- my gut (with no data) says it won't, and it would be a shame to put all the work into to building it that way, and them have it start leaking in 6 months -- not to mention the 6 inches of water in your basement :)
GaryGary gary@BuildItSolar.com www.BuildItSolar.com[ Parent ]
here is the drawing http://s2.photobucket.com/albums/y39/LanceA0/house/?action=view¤t=hotwater.jpg [ Parent ]
One important safety thing. You show two valves that can be used to shutoff the flow to the coil in the wood furnace. You must have a pressure/temperature relief value on the furnace side of those valves. Not having the relief valve on the furnace side of these shutoff valves is exactly how some homes have been blown up.
Otherwise, the only problem I see is that it will be difficult to provide freeze protection for the collector? This kind of system in which water to be heated is pumped directly through the collector is usually limited to climates that don't get freezing weather.
as for the collector that will be used only in the summer/warmer months. thats why there is a set of valves and a drain so when it gets cold it can be shut down for the season, and the wood burner will start heating the water.
now that i got the plumbing loop figured out, anyone have any ideas on how to control the pump so it doesnt have to run constantly?[ Parent ]
A bit of background: They run the small coal water heater in warm weather. The coal stove runs in cold weather. It is the only domestic heat. The silvery tin looking duct stuff around the stove increases air flow and makes the home more evenly heated. That silly thing really get the air moving!
Need that Magic Part thing. Bleeder? Proper name escapes me now. Long day. Without it, pretty much it ain't gonna work very reliably.
Need lots of safety valves.
Need lots of valves to switch between 'furnace' and the summer 'water heater'.
Need valves with removable handles so grandchildren don't shut off something that causes a serious issue. Again.
Need a plan to take care of the T&P valve, because it WILL Pop-Off a few times before you get the logistics worked out. Hence the CU pipe on the floor going to the floor drain.
Pay attention to how level everything is.
I don't show all of them, but Need lots of safety valves.
This area like to use NG water heaters as storage tanks because they have more water ports. I don't quite get it, but thats what they use.
This particular system puts a pipe on the chimney on the NG water heater and gravity feeds warm air to the bathroom. It is removed for summer and the water heater's chimney is stuffed with a few handfuls of fiberglass insulation. (all my idea, BTW. It may be the only one like that) :) I REALLY hate cold showers.
Need lots of safety valves. In case I didn't mention that before. At least 4 T&P valves in this thing. Maybe 6. It is that serious!
Not sure how organized the pics will show (it says there are 11 though I can only find 10), but they are here,
http://s701.photobucket.com/albums/ww20/ghurd1/Pumpless%20Water%20Heater/
G-[ Parent ]
