Amberwolf's DIY solar water heater

I started this earlier this summer, and will have some of the earlier stuff about it in hte next post once I collect it from my housefire thread where I'd posted it originally,, but for now here's it's current status:



I finally got the thermosiphon part setup, with the outside solar heated tank hooked into the main system / electric tank (which has had it's breaker shut off since earlier this year, as it's been unneeded). No leaks yet, though I ended up using pipe joint compound that I had to go buy yesterday, where I'd intended to use thread tape I'd already had from long before the fire, but I coudln't find that tape now that I needed it (though I'd had it not all that long before). Naturally, as soon as I installed it all, and was putting stuff away, I foudn the roll of pipe thread tape, in a totally different place than anywhere it should've been.

After the sun sets, I've been covering the tank in blankets to keep wahtever heat is in there overnight, till I get hte box built around it. Then I take them off once the sun is hitting it.



I'm still using hte wall mirror (which I found in the alley behind my house earlier this year, I think it was), leaning against a chair to get any reflected sunlight I can onto the shadowed side of the tank. I move it aorund thru the day fi I'm there, and if not I position it so it'll reflect for the longest time at hte peak of the afternoon sun (so it'll be warmer for when I get home some 3+ hours after sunset, and some 5 hours after it doesn't get any sun on it).





Presently, the Thermosiphon function itself doesn't seem to be working quite like it should; it's probably insufficient height difference between storage tank (whcih needs to be above the solar tank AFAICR), or maybe I have something plumbed wrong, or the tank isn't getting hot enough yet, or something. Also I haven't built the reflector/greenhouse box for it yet; tha'ts next.

I expect that I'm gonna have to connect the cold water inlet not up at the normal inlet on the solar tank, but instead at the drain plug on the "bottom" of the tank. And the cold water outlet of the storage tank inside not T'd at the same as it's inlet/source (as it is now), but instead at the drain plug on it's bottom end.

I probably should've done that to start with, but the diagrams and descriptions I'd found and looked at before generaly showed it just T'd into the regular lines, parallel to the storage tank's inlet/outlet, so that's what I did then. But that's not the only way people do it, and I didn't read enough stuff before I started (one of the disadvantages of not having internet at home, is not bieng able to jus tlook up stuff whenever I am thinking aobut it and have time...I have to make lists of stuff to get done while I'm out, like today, then do whatever I can while I"m at wifi, whcih often doesnt' have neough time for researching stuff like this, and lots of pages don't save properly for offline viewing, nowadays).


At least that' part's easy to fix. The height difference is not--the storage tank inside is pretty much gonna have to stay where it is, and how it is. Well, I *could* drain it completely, disconnect it from the plumbing, including the safety-overheat/overpressure drain, build a stand that would lift it up about two feet, and still have room above it and below the cieling to reach up there adn reattach plumbing to it, and not have tsuff pushing against the cieling when done. But to do that, I would have to go buy longer new hoses to connect it to the cold and hot water lines (at the least, a new one for the hot water outlet line, cuz I might configure the cold inlet to be from the solar tank only).

And I would need a completely new line to go from the safety vent on top to it's plumbing at the wall, whcih is not a normal line--that one is all soldered together as a bent and jointed line, right up to the threaded fitting that is already installed into the top of teh heater. I would probably have to cut or desolder that line in order to even take it off, and resolder it afterward. And the tank couldn't quite go right where it is now, it'd have to move over at least a foot or more, cuz the wall piece for this plumbing sticks out over the top of the tank a lot mroe than the other two do.


Also it sstill isn't on the roof where it can get the best sun: it's still at ground level, with the pipes just running thru a window then the backroom into the utility room. When I get the box done and it mounted on the roof, those will be moved so they go out the dryer vent (which I don't use for a dryer anyway, as I use a clothesline 99.99% of the time), then up to the roof along hte outside wall.



I considered shortening it considerably, by running thru the roof vent of the utility room, but that has a fan inside it that I'd have to take out first, and I'd also have to ensure the top was still "capped" in a way that wouldn't allow water in, and I'd rather not deal with all that.


When it *is* on the roof, it's probable that the thermosyphon process would run backwards, so I will probably end up having to isntall a pump in line with one of hte pipes to it, controlled by a thermostat. Or rather, by BOTH thermostats, in combination, somehow. (probably need actual temperature sensors).

What it needs to do, if I do have to do this, is start circulation only when the water in the solar tank is hotter than the water in the storage tank by some amount (to account for losses of heat in the piping and such, during the transfer).

Presently, with the original thermostat from this heater pinned between the strap holding it to the dolly and the tank itself, out of direct sunlight so it gets a better reading on the tank surface instead of how hot the sun makes it , I can hook a multimeter on continuity setting across the thermostat, and find out approximately what temperature the water is at by turning the thermostat till it clicks, and guestimating what temperature the pointer of the dial is at (it only has three markings, at 3 of the 4 cardinal points on it).




I'd like to put an actual temperature sensor *inside* the tank, but tha'ts not practical due to the pressures. I'd probably screw up and make it leak or something.

If I could accurately measure the resistance of the heater elements in it, and knew or determined their thermal change curve, I'd be able to use those as sensors. But I havent' attempted that yet. Not totally sure yet how I'd go about it.

Another solution is to epoxy a little sensor like the LM358 to the "dark" side of the tank, wire it up, and cover it in sprayfoam insulation so it will be reading the tank and not the air around it. Theres a number of easy circuits out there to use one:
http://www.google.com/images?q=lm358+temperature+sensor
Those and/or other sensors found on motherboards as chips I could prbably desolder and MAYBE wire to by hand (using my magnifier-camera workstation and some "helping hands") are a cheap solution that I probably already have all the parts for.

I also have some things like the BBQ sensor that I could do the same kind of thing with, but I'd have to determine where it's alarm output comes from, or make a setpoint in it for a temperature and build a circuit that detects when the piezo speaker is sounding and generates a latched signal from that. It may well be easier ot build the whole thing from scratch, and just calibrate it's output so a multimeter reads it's votlage output as degrees.



One last thing left to do on it is to get more puffy blankets from Goodwill or wherever I can get them for next to nothing, and wrap the in-house storage tank in them to give lots more insulation, so more heat is stored for longer. (since there's no fire risk, without any electric heat source to the tank, shoudl be no problems in wrapping it like that).

History posts, working backwards from now:

http://www.endless-sphere.com/forums/viewtopic.php?f=1&t=49550&p=958510
http://www.endless-sphere.com/forums/viewtopic.php?f=1&t=49550&p=954720
http://www.endless-sphere.com/forums/viewtopic.php?f=2&t=12500&p=953814
http://www.endless-sphere.com/forums/viewtopic.php?f=1&t=49550&p=947267
http://www.endless-sphere.com/forums/viewtopic.php?f=41&t=62888&p=940357
http://www.endless-sphere.com/forums/viewtopic.php?f=1&t=49550&p=939229
http://www.endless-sphere.com/forums/viewtopic.php?f=1&t=49550&p=938618
http://www.endless-sphere.com/forums/viewtopic.php?f=2&t=12500&p=932066
http://www.endless-sphere.com/forums/viewtopic.php?f=1&t=49550&p=926042
http://www.endless-sphere.com/forums/viewtopic.php?f=1&t=49550&p=917833

It's first tests:
http://www.endless-sphere.com/forums/viewtopic.php?f=1&t=49550&p=913261

This is how homemade solar water heaters are made in Brazil:



It consists in a refective film (usually the inner part of milk, juice and other liquids box) inside a pet refeclting the light to a black tinted pipe. The water reservatory stays above the heater and physics will do its job: cold water goes down and the hot water goes up. A tube floating in the reservatory will only pick up the hot water, since it will stay at the surface, which is the place hot water stays.

Its pretty efficient, simple and cheap. Made to stay on the roof.

In our house we have same type solar heater as the picture shows, but not homemade. Its made out of some hollowed panels. And dude, shit gets hot, more hot than the eletric shower can warm. Really hot, boiling hot.


I like your build, warms the watter right in the reservatory, it has a good avantage. The systems i showed have to be air-proof, else the thermodynamics won't let the hot water go up to the reservatory.

Thanks--that's one way I could sure do it if i had enough pipe (I might have enough steel pipe, but I'd have to weld it all together first).

The best I'm getting out of this so far is lukewarm water, which is better than without it (that'd be pretty cold, nearly chilly). But it's nowhere near as good as when i used it directly, as the shower-only system. So it's gotta get some severe improvements before I can use it as a whole-house system.

I dug out the 1/2" plex (lexan?) panel (one of 3 Mark gave me a few years back), which is so old that the sticker paper on it is dried out completely onto it, not peelable. So I wet an area of ground under a tree where sun won't hit it to dry it out, then laid the panel on that. Then I laid a towel across the topside of the panel, wet it down, then left the hose just barely dripping once every few minutes to keep it wet all day/night.

This morning I fairly easily scrubbed off the topside, and flipped it over, scrubbed off some of the other side (now the top), and scrubbed off what little I could of that, then left it with the towel on it to soak for today. (the wet ground wasn't enough to actually soak water into the paper).





I also checked out the plumbing points on both tanks, and the drains on each one are, of course, not NPT threading like the stuff I already have on the PEX piping. They are gardenhose type instead. One can be forced onto the other, but it'll damage the threads, and doesn't seal properly.



I have a bunch of adapters and stuff off the salvaged refrigerated feeder-fish tank, but none will do what I need. Most are gardenhose to gardenhose type, and all are male thread on both ends. One is NPT to GH, but is also M-M. If it was NPT-F to GH-F, then I could use it for the in-house tank end. If it was NPT-M to GH-F, I could use it for the solar tank end.

So in order to change the plumbing setup, I probably have to go buy something.


There is one possibility I have to check out first, and that is that the plastic GH-thread drain valve on the bottom of the solar tank *might* be removable without destroying anything. If so, *and* if it is NPT female threading on the tank where it goes in, I could flip hte cold-side PEX pipe around completely, so that the male end of that (presently on hte in-house tank) threads directly into the solar tank's drain hole.

Then the female end of the PEX (presently on teh solar tank) would thread onto that NPT-GH M-M adapter's NPT end, and the GH end of the adapter would go onto another adapter made with a F GH on each end of either the shortest possible piece of actual garden hose (cut from the best of the hoses I have), clamped on with hose clamps instead of the usual plastic GH stuff, *or* using a VERY short piece of metal or PVC pipe clamped and gorilla-glued (to ensure a seal) to the GH F ends. But this would be a potential failure point, AND it would be inside the house itself, so I would rather not do this if I don't have to.

I'd be better off buying an NPT-M to GH-F adapter, in that case.


Anyway, what that would do is change the system's water route so that
--Cold from main supply goes into the in-house tank's normal cold inlet via the original pipe.
--Cold water can then thermosiphon out the bottom (drain) of that tank, out to bottom (drain) of the solar tank, via one PEX pipe.
--Hot water can then thermosiphon out the normal top outlet of the solar tank, in to the T junction of main house piping and the normal top outlet of the in-house storage tank.

This should improve the thermosiphoning process a little. Probably would improve it a lot more if I coudl raise up the in-house tank more.





But since later on, I probably will have to put a pump in the system anyway, I might as well get started on plumbing that in, anyway. I've gotta dig the pump out (was an old fish tank pump from a very large stacked-wall-tank aquarium system), and make sure it can handle a pressurized system (normally it doesn't have to handle *that* much pressure, in it's seals and housing). Eventually, I'd probalby have the pump on the roof with the solar tank, so that it doesnt' have to deal with the gravity-created-pressure as well, but right now it's all ground-level so not worried about that.


So...then I also gotta work out a thermal control system. While I've been here at BK for wifi this morning, I've been poking around to see if anyone else has ever used the old heater elements as thermal sensors, but haven't found anythign yet.

However, it's been really hard to concentrate with this loudly complaining moaning whining grunting woman behind me, she just never shuts up.... She finally left a moment ago, after she spent what felt like forever harassing people about ice and bags for her cooler, and spreading everything out all ove rthe table and floor to repack it all again and again into her bags. I think she is like my oldest sister was: paranoid schizophrenic; she did the same things. But I don't know, and thankfully don't have to worry about it. :/


I also thought that I could take a heater element out completely, cut or break off the actual element, and then use the nubs as electrical connections from the outside world to the inside of the tank, and connect a thermal sensor that way. Moutning the sensor on the nub, and sealing it against corrosion, those I'd have to work out and/or experiment with.


The simplest though least accurate way is to glue the sensor to the tank's outer wall, halfway between the cold and hot ends, in a spot that's never in direct sunlight if possible. (or one at each end)



For now, the best I can do is turn the tank so the hot water outlet is at the top side, and the cold inlet at the bottom, since both are in the same end of the tank ATM.



Well, anyway, that's it for now.

This is the Iwaki pump I'll probably use:

surrounded by the adapters I've got and/or made so far for things.


I've already forgotten what was on the label, and it's hard to read at the angle in the pic, but I think it is 6.5 meters (21.3 feet) head height, (so I could EASILY pump all the way up to the roof with it), and I think it said 52 liters per minute max flow (presumably with zero head height).

It has male NPT threads on both inlet and outlet, which is good. It means that if I want to test the theory out right now, I can use it inline wiht one of the lines (probably the cold line to the outside tank to minimize heat thru the pump) with jsut the garden hose adapter on the one end, outside. I think...I have to draw it up again to be sure; I can't keep stuff straight in my head anymore like I used to.


The cooling fan on teh back end is cracked again, but since I wouldn't be continously running it that probably doesn't matter much. it only needs to run long enough to swap the water in the solar tank wiht the water in the in-house storage tank, when the temperature is higher outside than inside.


As for that part, I guess I don't really need to compare the two, I could just do like Harold in CR suggested, and have a thermostat run the pump whenever the tank temp gets to 140F. If that's all I need to do, then I can put a relay setup to turn on the pump whenever the thermostat that's originally from this tank "turns off", meaning it no longer shorts it's connections (which would normally be running the heater in it).

I'd probably just have a little wallwart that runs a transistor driver for the relay. The driver's input would be shorted to ground (turned off) whenever the thermostat says the tank is below the pumping temperature. Then when it is above that temperature, the short is removed as the thermostat turns off, and it lets a pullup resistor on the input of the transistor turn the transistor on, which then turns on the relay. The relay then turns on the pump. Once the solar tank cools below the switchpoint, it'll turn the pump off.


I don't know for sure what temperature the pump is good for, though. I have to find that out, cuz it needs to work pretty hot, maybe up to 180F according to HinCR. But according to Iwaki's site, the magnetic pumps MD-series (which this is)
http://www.iwakipumps.jp/en/products/magnetic/135/md
will go up to 80C, which is 176F. I guess that's good enough.




For the box, I got the plex sheet cleaned off, but I guess I scratched it up pretty good in the process (it was a lot harder to get all the gluey gunk off than I expected). I might be able to polish it up some, but it'd be a lot of work.









I also have these, still (I remember seeing them in a shed not long ago):
http://www.endless-sphere.com/forums/viewtopic.php?f=2&t=22720&p=718084#p716311

they're pretty thin clear plastic, maybe 1/8" or a little thicker, but they're not badly scratched up, at least. Also are smaller, maybe half the size of the big thick sheet I cleaned off.

I had another idea, and that's using some of the glass off one of hte aquariums....

I forgot the pic of it, but there are some here:
http://endless-sphere.com/forums/viewtopic.php?f=1&t=41207&p=717121

Basically it's a large aquarium something close to 4' long and 2' high, and it is internally divided lengthwise into three interconnected aquariums, plus a "junk" area. So there are two ~3.5' x 2' glass dividers in it that I want to remove anyway, plus the ~2' x 2' divider at the end of those blocking off the last few inches of the tank.

The actual solar heater tank is about the same length as the panels, so I'd need bigger ones for the final version, but for now I could use these three glass panels to cover a large portion of the "breadbox" the tank will be in to focus sunlight on the back of it, and contain the heat within it like a greenhouse.

One other possibility is to actually use the entire aquarium itself, minus the internal dividers and one of the end panels, upside down, over the solar tank, mounted to whatever stand I build to secure the actual solar tank to the roof, and have more reflectors outside the "breadbox" plus the ones under the tank.

Then it would also be more able to get sun from any direction, during all seasons of the year, cuz the lattitude I am at means the sun moves north of me in summer, and well south in winter. If I build a stationary breadbox that's angled so that it catches more light in one part of the year, as most are done from the pics I've seen, then it'll be "wasting" light the other part of the year. Of course, I could build something movable, so during the major sun-position changes of the year I could re-angle it, but that would be more complex and not necessarily as sturdy as a simple solid fixed box.

However, I have no way of getting the aquarium up onto the roof in teh first place, not without great risk of breaking it. (there are some complicated ways I could do it, but I probably wouldn't want to). Individual glass panes, yeah, I can deal with that--but I wouldn't wanna take the aquarium apart to get it up there, then have to reassemble it. Partly labor, partly cost of silicone/etc materials to do that with (cuz right now, it's already all together, and would only require sealing up the holes pipes go thru, and whichever end I remove for the tank's endbits to stick out of).


I considered doing something similar, though quite a bit larger, using hte three panels from Mark (I'd have to clean off the stuff from the other two), and I have a couple thin green panels I could put on the ends, and that'd make quite a large clear(ish) box, not as good as a glass one, but it'd certainly help keep air movements from removing heat from the solar tank while letting sunlight in, which is half the point of the box.


I also dug out the old bedframe pieces that will be the tank mounting frame for the roof, and the pine and plywood bits that will be the base and rest of teh box.

Yesterday, before heading off to pick up an old crystalyte kit,
http://www.endless-sphere.com/forums/viewtopic.php?f=4&t=64279&p=962919#p962919
I pondered and setup and tested the pump in the system. Because of the connectors I had avaialble, and the little time I had to try it out, I ended up putting it on top of the in-house storage tank.


It will go on the outside solar tank instead, once I get the right connectors to do this permanently, so that any leaks in the system will happen outside. (cuz presently there's three extra connections for this).


I moved the cold-water input to the system from the wall above the tank (shutting off the valve there) to the washing machine's valved outlet, Y-d to the WM itself with a brass gardenhose splitter, since that's the threading for the WM outlets/inlets/etc, and for the drain on the bottom fo teh storage tank.



Then I used osme of the steelmesh enclosed hoses off teh aquarium (whcih are quite narrow inside and restrict flow a lot, but doesn't matter for my purposes) to connect that WM outlet to the drain on the storage tank, as the inlet to the system. I leave the wall valve off unless I am actually using the system, just in case there is a leak I can't see.
View attachment 1


Then the T that had been on the old wall outlet, to the tank's cold inlet on both storage and solar, is moved to the cold inlet on storage tank. The male adapter comes out, and the M-GH to M-NPT goes in there, and gets capped off by a GH-F cap (cuz I don't have an NPT cap). The F-F hose that ran to that inlet on the tank before now moves to the pipe that runs to the solar tank's cold inlet, and the output of the pump. The pump's input is directly screwed into the T, so the pump actually rests on that, sitting vertical. (it works fine in this position).


Even with some air in the systme, the pump is powerful enough to vaccum up the water until it reaches it, apparently. I thought I'd have problems and would need to prime it, but not in this case.


At the rate of ~52Lpm, that's around 13Gpm, so with a 30G solar tank, and some 100 feet of 3/4" (5/8"? I forget) PEX piping, it takes a little over 3 minutes of running to completely exchange the water in the tanks, I think (if I figured it right). It certainly works quickly.

So after I got done messing around with the battery on the crystalyte kit, and the solar tank was beginning to be shaded for the final time of the day, no more sunlight on it, I covered it in blankets liek usual, and turned on the pump for about 3 minutes to move it's hto water into the storage tank, and the storage tanks cooler water into the solar tank.

If I'd thought about it, I probalby should've done that once right when i got home, or even when I left a couple hours before that, and then again just at shadow time, but I didn't. That would've prewarmed the storage tank a little.


Now I gotta dig out my unused blankets and stuff, and wrap the storage tank in them to further insulate it. Then I gotta insulate the pipes and hoses themselves, though that part will prbably wait till I get the whole plumbing stuff done and decided, and the solar tank in a breadbox and on the roof.

All you need is a cradle that sits right on the roof. Use 2 X 2 or something similar for the frame and cover that with the clear plastic. IF you need to cut it, put masking tape on both sides and use a jig saw with finer teeth than the typical wood blade, something like 14 teeth per inch. Wipe a candle on the blade every so often, so the plastic wont stick to the blade and break something.

Clear panels all around is a great idea. Then, figure out how to cover it at night. This way, you don't have to lug a pre-built box up on the roof. Just make it so a good wind won't blow it off the roof.

Right now, I have a flat panel 2 X 4 frame with glass top and 15' of 3/8" clear tubing coiled up in it, laying on a rusty painted piece of corrugated roofing. No insulation, and, before the sun gets too low, the water is nearly hot enough to burn some people. I have to temper it with cold water while showering. I have NO tank at this time. I want to get a pre bent SS box tank placed in a crate full of stuff my Son will send down. Then, I can just weld it up with SS wire in the Mig welder.

We both get enough warm to hot water for a shower, IF the wife doesn't just let it run while soaping up. Pipes outside the house sag pretty bad, but, they haven't exploded, YET. :lol:

Harold in CR said:

All you need is a cradle that sits right on the roof. Use 2 X 2 or something similar for the frame and cover that with the clear plastic. IF you need to cut it, put masking tape on both sides and use a jig saw with finer teeth than the typical wood blade, something like 14 teeth per inch. Wipe a candle on the blade every so often, so the plastic wont stick to the blade and break something.

Click to expand...

Hadn't thought of the candle wax--good idea. I'm hoping to get by without cutting the stuff, but I dunno if that's possible.

As for the frame, it'll probably be various sizes of wood cuz I don't know that I have enough of all teh same size. :lol:

Clear panels all around is a great idea. Then, figure out how to cover it at night. This way, you don't have to lug a pre-built box up on the roof. Just make it so a good wind won't blow it off the roof.

Click to expand...

Some of our winds are really high...so I am looking at making sure the frame under the tank is thorougly connected to the box around it, cuz I am pretty sure that a tank full of water plus the heavy clear panels ought to weigh enough to hold down even in some of the winds we have around here in our "habibs".

I'm also thinking about just a "tent" of clear panel over it, using just two of them with the peak above the tank running east-west. It makes a smaller box with a lot less wind-profile, and would probalby still have enough room for two tanks at the base of the triangle, but even if not, I've only got one right now anyway.



As for something covering it for nighttime...per our other discussion I was thinking I could put pulleys above the peak of the box to run cables up and over it, down to the ground so I can pull the cover either direction.

Then the cover (blanket, whatever) would be wound around a pipe that's on roller pivots at it's ends, and secured to the pipe at it's inner end.

The pulley cables would go to another pipe that rides along rails just beyond the "ends" of the box, around which the other end of the cover is fastened.

Basically it'd be a lot like a standard pulldown window blind, except that it rides horizontally. I guess it's more like a pool cover.

I could probably even motorize it, using a bike chain and sprockets along the length of the path fo the cover, kind of likea garage door opener. But that's a littel fancier than I will go for at first, most likely.

Right now, I have a flat panel 2 X 4 frame with glass top and 15' of 3/8" clear tubing coiled up in it, laying on a rusty painted piece of corrugated roofing. No insulation, and, before the sun gets too low, the water is nearly hot enough to burn some people. I have to temper it with cold water while showering. I have NO tank at this time. I want to get a pre bent SS box tank placed in a crate full of stuff my Son will send down. Then, I can just weld it up with SS wire in the Mig welder.

We both get enough warm to hot water for a shower, IF the wife doesn't just let it run while soaping up. Pipes outside the house sag pretty bad, but, they haven't exploded, YET. :lol:

Click to expand...

FWIW, my system actually worked better (sometimes scalding hot by midafternoon) as just a direct heater for the shower, than it does now. It's obvious that thermosiphon is working a little bit, because the water int eh storage is never getting anywhere near as hot as it did before, but the water in the storage isn't cold, either, so it is definitely moving around on it's own...just not well enough.


So I am probably gonna have to put a check valve in the system (or a solenoid valve off an old washing machine inlet) that only opens when the pump is running to exchange the water.

Right now it's just lukewarm at best in teh storage tank, and fairly warm, not really "hot" in the solar tank, regardless of tank orientation, though I am limited in placement because of lenght of the pipes vs the shadows of house, trees, etc, down on the ground in the backyard (whcih is why it's going on the roof as soon as I get the plumbing worked out and the frame built to keep it from rolling off :lol: ).




Now...a question: Since I'm not using hte thermosiphon effect once it's on the roof, does it matter if I put the tank on it's side in east-west orientation, where it is easiest to cover with the box vs winds/etc. , or is it better to put it more upright in a north-south orientation?


The former would get better sun on more of the tank thru most of the daytime (meaning the water probably gets hotter overall), but the latter would get better sun on more of the tank in morning and evening (meaning the water gets heated sooner and longer).


I suspect that it would be better to do it east-west, horizontally, and it would certainly be a lot easier to do that, structurally, for the frame and the box and reflector.




Regarding measuring in-tank temperature, you'd said:

Harold in CR said:

You should have at least 1 threaded port in the tank that is not being used.

You have a LOT more access to stuff than I do, BUT, if you can get a small enough sensor, make up a capped off tube that can slip inside the threaded port, and put the sensor in the tube and just seal it enough to keep the temp from fluctuating. The tube will be immersed in the water, inside the tank.

Click to expand...

I hadn't thought of that, so thank you--I'll try that out using the "drain valve" on the solar tank, since it has the GH type threads, and I have a number of GH caps I can drill, sensor, and seal.

Should tell me quick enough if it works and if it's gonna leak or not.


If that works I could do the same for the in-house tank, I guess. Though, I think I would run a really thin wire to the sensor, thru the water supply hose that goes into the drain there, and thru one of the inlets of a GH y-splitter/valve, capped off like that. That'd give me the option of shutting the valve in event of a leak, with the valve (probably) just shearing thru the thin wire. And the leak would not be at the bottom fo the tank, but up higher where it wouldn't be *quite* as disastrous a flood.

I started to make up one of the caps with temperature sensor in it, but coudln't find the old electronic thermometer I was gonna use for that. :/ I was sure I had run across it since moving back in, but I either misplaced it or I left in the shed where I'd found it then, instead of putting it away with my measuring equipment (whcih I'm trying to get all in one place).

Anyway, since I didn't find that, I dug out some of my old blankets and stuff, things mostly usable only for doggies in their present condition and wrapped the storage tank and the PEX pipe from one tank to the other in them. It's not really much insulation, but it should make a difference, especially since today is kinda breezy, mostly cloudy.

Dug out more of the stuff for a temporary breadbox down on the ground level until I get all the plumbing bits for interconnects to permanentize the roof version. At least it will tell me if the scratched up plex will work well enough for my purposes.

Over the last several days, I've experimented with little tents of plastic to keep the winds from blowing all the heat off the tank, and they may have made some small difference, but not enough to be sure.


The first was just to put some plywood on teh shaded end, and the scratchedup sheet of plex at a 45 degree ish angle leaning against the tank itself on the non-sun side with the mirror sending sun thru it, and the sun thru clear plastic bags on the other side. Made about zero difference I could tell--may have even been worse. Whatever heat wasnt' carried away because of it was made up for by not being put in in the first place by being diffused or reflected by the plastic.


Variations on that up to putting styrofoam under the tank made little or no difference.


The last variation was just to spread out a black plastic sheet and tuck it under the tank's dolly on the sunny side in a way that keeps much airflow from happening under it, while leaving the mirror side open to shine sun under it with the mirror, worked best, though so little difference it could've been insolation differences.



The biggest single differnce was to insulate the PEX tubing with old blankets/etc rolled around them, along the whole length from solar to storage tank. It's not enough, and neither is a puffy blanket wrapped around the storage tank itself.


I'm still working on getting the old paper off the next big sheet of plex/lexan/whatever, so I can try the pair of them as a tent over the tank, and seal it up as best I can, and use that black plastic sheet under the tank, with layers of styrofoam under that, to keep the heat from soaking into the ground.
It's taking a whiel, becasue i don't want to scratch it up like I did the first one. Instead I'm just keeping it damp and as I have time and energy I go rub it with a towel or rag, and each time I get a few square inches of it off, at most.



It still doesn't do any noticeable thermosiphoning. I've verifeid as best I can that all the cold and hot connections are in the right places, and AFAICT it *ought* to work a little, at least, but it doesn't seem to.



The pump works fine to shuffle water between them very quickly, but I have found thru experimentation that it takes more like 4.5-5 minutes to actually move all the hot water out of the solar tank into storage.


Now, ther'es a problem I hadn't thought of till last night, which explains most of why I only get lukewarm water even if the solar water is pretty hot: the storage tank is 50 gallon, and the solar one is only 30.


So even if I put 30 gallons of 120F water into a tank that was holding 50 gallons of room temperature water, it's not gonna heat up the tank and the other 20 gallons of water very much.


I guess I really will need to increase the solar-heated water amount, by either finding another tank (no luck so far) or putting as much of that piping I have together as I can, to stick in the breadbox with the tank, and absorb more heat to put into the storage tank.

Then, also, will need to see about circulating the water more often, so the cold water gets warmed up more, and warms up the storage tank itself more. Though, I don't know that will actually make a differnece, as unless I insulate the pipes and the tank even more, it jsut puts the water in a place wher eit can lose heat faster than it's put in.




In the meantime, I ran across a can of black primer in one of te sheds, while looking for stuff to mount the X5304 on CB2, so I cleaned off and wiped down the tank, and scrubbed off all the loose flaky orignal paint with the wire brush, then sprayed it down with the primer.



It makes some difference to how fast it gets hot, and how hot it gets, but I'm not sure how much, since yesterday it kept getting cloudy and today it was really sunny for te first half of the day (and it'd've gotten hotter anyway).
View attachment 1

Around midday as it began to get slighly cloudy, I also moved the tank northward a few feet, to the limit of the PEX pipes, as much out of the midday shade of the nearby mulberry as I could (with the change of seasons, it's pushed the shadow of that tree more and more onto the tank, which I knew would happen where it is, but can't be helped yet).


I'll get this thing worked out eventually, but I think that I may just nix the storage tank for a while, and plumb the solar tank directly into the house stuff until I work out the rest of the system. Or put it back on teh shower alone.


Closeup shot of Tiny being bored with me doing this and the X5304 wheel mounting/testing on CrazyBike2.

What you are doing, is, you are heating the air all around that tank. When you had it hooked directly to the shower, it could keep up with hot enough shower water. Now that you have a second tank, inside, it will not produce enough heat just sitting outside of a box.

Can you make a cardboard box to cover the tank, and lay a transparent sheet on the open top ?

As you found out, just insulating the pex tube made a slight difference.

I was hauled into court one time, because the customer didn't think I had made his water heater correctly. I did a 2 tank insulated breadbox with a double glass top. I put a sensor inside the box and it would turn on a pump to send hot water, (150°) into the house into the water tank in the basement. That was why it needed the pump.

Anyway, I put his inside tank on it's side up in the floor joists. He would not let me insulate the tank. Said HE would do that. Then, his family would do 5-6 loads of laundry all in 1 day. I TOLD him you can't do that, so, into court we went.

He got to speak first, then I got to speak. I asked the judge if he knew how long a cup of coffee would stay hot, with AND without insulation, like putting the coffee in a thermos bottle. He said the thermos bottle was definitely better. I held out both arms and said, there you go. Customer admitted the pump would come on, a couple times a day, as far as he knew, even doing the laundry.

Judge told the customer " you lose, insulate your tank and piping". :lol: :lol:

Yeah, I guess I know pretty much why it isn't able to do it....

In the middle of summer it might have.


I haven't made the box yet because I'm still cleaning off the non-scratched plex, to make a "tent" with the two big sheets over the tank and the black plastic sheet under the whole thing, and some plywood and styrofoam and whatnot under that and on the ends. It ought to help a lot. Since I am off the next week, I should be able to complete that stage.


The other issue it has is that the PEX isn't long enough to get the tank out of shadow in this season and still sit more vertically, with more of it directly facing the sun. That wasn't really going to be an issue since the PEX is only meant to be long enough to reach the roof. :/

If it was longer, I'd sit the tank up at around 45 degrees with the "top" pipe end pointing north away from the house, and the bottom drain end pointing south toward the house. Then it would get more direct sun on it at less of an angle, heating it faster, and also have more of a differential between it's hot top end and it's bottom cold end, which might improve the thermosiphon (might not, given that it'd then be almost the same height as the storage tank inside).

It's not even really long enough to be able to put it east-west orientation on it's side, which would also help the solar heating (it's worked best in that orientation in most of my previous experiments, and the mirror needs the least moving around to keep sun on it's shaded side like that, too). Turned east-west, it either has to be moved into areas shaded more during the day, or the bend in the PEX ends up pretty sharp and pulls pretty hard on the connections to the tank.

I *might* be able to rearrange things a little to fix that, without the storage tank hooked directly into the cold water system in the house at the top, because I can move that tank toward the utility room door by a couple of feet, if I disconnect the wiring harness to it (or if it turns out to be long enough; I don't think it is). That migth give me enough to move it fully into sun.


Anyway, once I get hte "tent" of plex over it it should help a lot, and once I get the rest of the materials out of the shed for hte roof box it can go up there and the rest of the problems other than the pump switching stuff will be taken care of.


(although I fully expect new problems to arise that I either didn't think of, or that I've read about from others).

I got the plex cleaned off enough to be worth trying in the "tent" formation:




Which has a west temporary end made of a partial triangle of plywood, with it's bottom left corner covered by another partial, an dbricks against the bottom edge to hold styrofoam against hte gaps. It'll be clear plex later, once I actually ahve a frame to hold everything together and enough plex cleaned off to make the ends.
View attachment 3


I taped the top edge with clear packing tape, where the two sheets touch, and they're basically held up by that triangle of plywood, and taped across the top part of the endcap to keep the sheets together even if the dogs bump into it playing tugowar again.

The east end is a clear plex piece (uncut for now) and some styrofoam to fill gaps, and some towels and whatnot wrapped around the pipes, with some packing tape to keep it from falling apart when dogs run into it.

Underneath teh whole thing is a black plastic sheet, and styrofoam under that (and on top of it on the south side, too, cuz I didn't extend it far enough originally, and had a huge gap of exposed cold ground (at night). I really need to completley redo teh whole thing but that won't happen until either I can see some improvement in it this way, making it worth little fixes, or I figure a new way that would catch better heat and hold it in, with what I have around here right now. (and not including painting anything other than the tank black yet, cuz it'll get that when it's actually "done".

The mirror is north of the systme as close as I can get it without it being shaded by the box/stuff, and I can either leave it flat-on to the thing for the average best sun during the day, like when i won't be home to turn it, or I can periodically go outside and turn the thing to better reflect the sun dirctly onto the tank's otherwise-shaded north face.
View attachment 2


it was very breezy and very cloudy most of the day, until only a couple of hours before the sun gets to much behind the big southwest mulberry (around 315-330pm) to get any real sun onto the unit, other than some reflection via the mirror if I move it far enough north).

So today's experiment only proved tha tit does indeed help hold in heat, because when it was cloudy and around 65F or lower, the enclosure was rising in temperature to around 75F. Later when it was sunny, the enclosure temp (in it's shaded area under the tank, same place as before) went up to around 85F, when it was still around 73F outside.

I don't know what hte water temperature was, as I haven't got that sensor worked up and installed yet. It wasn't warm enough to notice thru the pipes, unfortuantely, during the pump transfer, but on a sunny day I'm sure that would change greatly, and it would also help if I get the plex cleaner, and everything inside the enclosure painted flat black.

Well, a sunny day did indeed imrpove the water temperature--and it also started the thermosiphon process for the first time!

Itw as the day after the previous post. I hadn't even thought about it, but a little after middayish, I had pressurized the system to verify somethign else, and then went to wash my hands and some dishes and stuff, and by older habit I turned the tap to hot, instead of cold like I normally woudl (cuz I don't usually have pressure in the hot system, since I don't yet trust all my plumbing on there ), and the water warmed up more than I expected, even with sun on the roof heating attic pipes, adn then it got really warm, measured at 108F when I got over my surprise.


I went to the system, and checked under the sheets/blankets wrapped around the PEX picpes, and could feel one PEX was cool (lower than room temperature) and the other was warmer than body temperature.

However, even though I am *sure* I have them hooked up correctly, the warm pipe was the one marked COLD, which is hooked up to the COLD side of each tank!

So that's a little wierd, but as long as it's workign I don't care.


That afternoon, around 330-4pm, when teh shadows of the big mulberry covers the box/tank outside, I covered it up with teh blankets, and also with an ex-pavilion cover I finally found in a shed (shed sorting and cleanup is this week).



Tiny says she likes this setup, probalby cuz it's warmer than the now-cold ground (whcih she really likes in summer, but not so much now that it's getting down to the mid-high 40s F at night).





Further checks today and yesterday find that the air in the "tent" gets up to 130F at peak, around 130pm ish, dependin gon wind. (was windier today, so only got to 115F).

Water temperature directly out of the system I don't know, but out of the faucet it was about 105F during a cleanup shower I took well after dusk. \

Dunno what it is right now, but I'd bet it's more than warm enough for a shower.


Probably even warmer, since I made one plumbing change taht shouldn't affect the thermosiphon effect: I remvoed the now-unneeded pump, and moved the cold inlet of teh system from teh drain of teh storage tank inside, to teh drain of teh solar tank outside. Teh two tanks are still conected at tehir Hot and Cold inputs. The Hot is T'd to the wall inlet, and the Cold is a direct connection from one tank to the other.


What the change means is that the cold water inlet in the solar tank will push teh hot water out of it into the storage tank, so there will be more hot water for longer, shoudl I need it. Plus, most importantly, it adds the cold water to where the heat source is, and pushes teh hot water to where it will need to be stored anyway.


It is possible that this will change the thermosiphon effect, disturbing the cycle flow whenever I turn on the tap for hot, but I haven't tested that theory yet. If it does then maybe I need a check valve in the cold side?


But basically I just don't want to put new cold water into the storage tank where it just makes teh stored water cooler.


Solar tank is still on it's side, "top" end a little higehr than the drain end (but not a lot). Storage tank is still vertical just as it was isntalled druing the rebuild.


For today I did not move the mirror around except in very early morning to get the sun that hits north of the tank rreflected onto it's north side, while the rest of the tank was completely shaded by trees across the street and my own southeast mulberry, just by turning the mirror in place.

And in the afternoon, as shade from teh southwest big mulberry hit teh south face of teh tank, but leaving the area north where the mirror is still in sun, I turned the mirror to get that onto the tank for as long as possible.

Otehrwise the mirror lay facing south, and slightly upward, to get the average sun onto the tank as much as possible withotu moving it around.


Tomorrow I will leave the mriror ONLY in that position, and see what happens--cuz I wont' be here to move the mirro thru the day most fo the time.



Anyway, it is workign as well or better than I expected, now that it's finally thermosiphoning.

Yesterday by shade-time it was about 108F water temperature out of the faucet, and around 120F air temp in the plex "tent". Still no sensor to tell what tank water temp is, but it would just be for data purposes as right now it doesn't matter--it's working well enough as-is.

I'm now considering leaving it at ground level permanently instead of a roof installation, because I honestly didn't expect with all teh shading for it to work this well in winter with just a juryrigged setup.

Since it will get more insulation and whatnot once it's in a more permanent "breadbox", it'll get hotter then. That should easily make up for the colder winter temperatures, though the piping will definitely need much better insulation than it's got right now. :lol:

I've got a couple more people now keeping an eye out for glass I coudl use for the covers. (other than disasembling one of the fish tanks for it's glass, which I could do if I had to).

2 thumbs up, AW. When I was in Ag school, after the "Nam experience, The teacher told us, " the cheapest cattle feed in the world, is fertilizer". I will alter that slightly, with " the cheapest hot water is created with insulation. :lol:

Good job, so far. 8) 8)

Thanks--but it might be premature.

Earlier I thought that the thermosiphon might not be working, and decided to wait till afternoon when teh tank heated up a lot to find out. Kept checking and the PEX on both sides has been cold all day, even though the air temp in the "tent" has reached 130F easily (it's down to about 110F now, as the shade moved over it, so I covefed it up with the blankets/etc for the rest of the day/night to lose less heat).


I didn't have a direct way to check the tank water temperature, without taking parts of the tent apart, so I turned the valve on to let pressure into the solar tank from the cold inlet at the drain, and turned on the tap at the clothes washer, which is the closest one to the storage tank/solar tank junction. That stabilized after a minute to 116F water, and when I checked the PEX, it's only warming up the hot side pipe. The cold side stayed cold (which it should, since the inlet at the drain should fill into the cold part of teh tank, though eventually the disturbance of water entry will swirl cold and hot water together inside the solar tank).


When I felt the metal parts of the storage tank hoses, though, they're still cool. So if any water is flowing out of the storage tank at all, it's cool water, but probably little or no water was coming out fo that tank.

That's disappointing, but it's probably a consequence of my removing the cold-side pump (even though I wasn't using it) and moving the cold inlet to the solar tank. I'm not sure how it could stop the thermosiphon process, since I did not use the system for all of last night and all of today, so if a cold-input into the solar tank disturbed the process, it should've restarted by now.


I definitly wish I had more sensors in each tank and in the piping, not only for temperature but also for flow direction and speed. I might be able to get temperature sensors going with stuff I have here, but I can't think of a simple easy leakproof way to make a flow sensor, without going with electronics I would have to buy and/or build and program (neither of which I can really do), or buying commercially-available flow sensors (again, money I don't have for this project, especially since it's only for curiosity's sake, and maybe a little troubleshooting).



Now, even if it *doesn't* thermosiphon, the system wil *still* give me hot water--but it wont' be stored overnight very well, once it gets a lot colder outside, without a lot more insulation than i'd planned on. (vs storing teh heated water inside the inhouse tank that's already self-insulated, plus any additonal insulation I add to it, plus the house itself as insulator, etc).

Since the main (only?) things that changed between thermosiphon working and not were:

--pump being removed (but not being used anyway)
--cold water input being moved from storage drain to solar drain (but a whole day tested without flowing any water into the system from it, valve shut off)

Then I decided to put the pump back on and see what happens. It is possible the pump was acting as a kind of valve, if it happens to be easier for water flow in one direction to turn it, but otherwise it's vanes block enough flow to stop water in the other direction. (I have no idea; case is not clear so can't tell, not gonna open it up and risk damaging seals just to look).


I did put it back on in a different place, though. Originally it was in series with the cold PEX to the solar tank from the cold "inlet" on the storage tank's top.

This time, I put it on the hot outlet from the solar tank, output from pump to the hot PEX to the storage tank.

Since doing this took some water out of the tank and PEX, and left air in it's place, and thermosiphon won't work with air in the lines, I turned on the cold pressure into the solar tank from the wall, and turned on a hot tap in the house to bleed the air out of the system. I also then ran the pump just a moment to be sure it would circulate water, and it does.


So now I wait and see if thermosiphon restarts. If it doesn't, I can just use the pump to transfer the water...but I'd rather not have to, cuz to do it "rigth" means creating that thermostat system to compare tank temperatures with each other, and have the pump swap the water when the solar is hotter than the storage.

If thermosiphon works, then the system will be fine like it is, and it is MUCH simpler and less failure prone.


I *would* still like to put a check valve in the system, to keep water flowing only in one direction. Harold in CR says to be sure it's a flapper type, not a spring type, and that makes sense. I would prefer to put it at the cold side circulation PEX, so that when I allow cold pressure into the tank via the drain-input from the wall, it doesn't reverse the flow thru the cold PEX, but instead lets it just stop momentarily. That would be less inertia for the water to overcome to restart thermosiphon whenever I use hot water from the system.



It may come down to moving the cold pressure inlet back to the storage tank, but if I do that then anytime I use it I'm putting the cold water in with the heated water I'd rather be keeping warm.


However, if I only ever put the pressure into the solar tank, then even if the solar tank is cold (days of clouds, rain, etc) then it'll still be pushing *that* water into the hot water pipes of the house, rather than what's in storage.


So I guess the "optimal" solution is one that uses a thermal sensor to turn on or off a solenoid valve for the cold pressure inlets on *each* tank, and it turns on the one for the *hotter* tank. Then I always get the hottest water I can out of the system...though it's going to make that hotter water colder just by dint of pushing the cold into it.


I guess there's no perfect way to do it.



Well, if I had gravity feed, with both tanks on the roof, then I could avoid *any* cold inlet into the system until *after* I'd used up all the hot water...but that adds the complication of getting all the air back out of the system afterwards.

No perfect way....

Harold in CR said:

Got any hot water ??

Click to expand...

Hot enough if I use it any time from late morning up to around 9pmish (about 6ish hours after it's not gotten any sun on teh tank . Maybe 100-105F by then, but it's well up into the 110-115F at it's hottest part, between around 2-3pm when it gets full sun on teh tank face and the mirrored sun on the back. I'm sure it's a little hotter in the tank itself, but it probably loses a fair bit of heat in the 50 feet of PEX between it and the house input, and more in the house piping itself.

Air temp in the tent reaches around 125-130F at peak, from what I've seen. As soon as the sun starts to get shaded in late afternoon, though, it drops about 10 degrees in a very few minutes, and by the time it gets fully shaded, it's below 100F air temp in there.


And so unfortunately it cools off faster than I'd like after shade-time, and doesn't get as hot as I'd want, even with the insulation under the tank and the blankets/etc over the plex tent. It's still 80F air temp in there by morning, though, even when it's 50F air temp out there. So the tent and insulation does work, just not as well as it needs to yet.

And that's with me using it directly from the solar tank.


I'ts still not circulating unless i use the pump...but like before, using the pump means it mixes 30 gallons of hot water with 50 gallons of cold as it pushes it into the storage tank (most of the cold is probably pushed out into the solar tank, but that's still almost as much cold water as hot water so it ends up lukewarm at best).



OH, and I realized that feeding the cold only into the solar tank would be stupid if I want to use the stored water, so I now have cold input at the drain of both tanks (from the wall), and whichever tank I want to use the water from is the one I turn on the cold pressure to. Otherwise neither is pressurized from the wall.

Basically there's no way to feed the cold into the non-storage part and still have it force anythign out of the storage part *and* still have it hooked up so that there could be circulation between the tanks, as far as I can figure out, unless I had some valve setup that acted like a relay, switching the plumbing around to put the tanks in parallel for solar heating, and series for actual use of the water.

That's more complicated than I'd like to deal with, at least right now, so I will simply have to use cold input to whichever tank I want to use water from.



Also, I mvoed the PEX tubing (presently wrapped in old unwearable clothes and blankets and sheets (mostly stuff that survived the fire but not the intervening time in the sheds) up off the ground by putting stacks of 4-5 bricks every few feet. So far neither the dogs nor I have tripped over it, yet.

it didn't change anythign about the lack of thermal circulation, though.

I keep wondering if it is just that the solar tank water is simply not getting hot enough to move?


It might also not be enough height difference between one end of the tank and the other, or between solar and storage tanks. The former I can do somethign about, but the latter, not really.


I've been thinking about a timer for the pump that runs it for a few seconds every few minutes, just long enough to get a flow started and keep it going. Or even if it doesn't keep flowing, it'll eventually force circulation of all teh water in the system. With the sun/shade problem I presently have, that might just make the whole system lukewarm, rather than really improving anything. It's still a lot less power used than it would take to heat the water electrically.



As the days are getting colder and shorter and the sun angle continues to change, there is more and more shadow and less and less sun on the tank, and it is rapidly approaching the point at which it isn't going to get enough sun on it to heat the water enough.


Unless I get another 100 feet of PEX and some couplers, to extend teh whoel thing out another 50 feet from the house, to get it in the nearly-unshaded middle of the yard, then I *am* going to have to put this on the roof as orignally planned, to get the most sun on it.


Another option that I will try first is to make a bigger "collector" box, that wont' have the mirror behind the tank tent anymore, but instead be an upright box with an angled front that uses both sheets of plex presently cleaned off as it's face to the south. That will double the amount of area the sun enters the box directly from, which even though a fair bit of that is shaded, might still heat upt eh tank more.

If I can, I will mount the mirror in there above teh tank and behind it, so that the sun shines down onto the mirror inside the box and is reflected onto the tank. The rest of teh box will be black, though since i don't have black paint yet I'll use this black plastic sheet and some black plex I also have, on the inside of teh box.

Just outside of that stuff will be as many layers of styrofoam sheet as I can reasonably put in there, and then a plywood/masonite/2x4 box around that to hold that stuff in there.

It'll be mostly a big triangle from the side, straight uprigth back side (north face), splayed out sides that are triangles, angled outward as best I can to try to let the most sun in up to the point it'd be shaded anyway. Then the whole south face will be those two sheets fo plex.

Then we'll see how well that works. if it's enoguh of an improvement, I'll leave it at that. if it's not, I guess up on the roof it goes.



Of course, I dunno exactly when I will get this done; I'd wanted to do it today but just couldn't get other critical stuff (housework mostly) done in time to get to it.

Not much new on this, except that we had some sprinkles with light wind beforehand, and the wind blew the waterproof cover off the blankets, so the blankets got wet enough and dirty enough to require washing (so they don't get all mildewy) and hanging out to dry (in today's ~15mph wind with 20+ gusts, mostly from the north-northeast).

So the plex tent hasn't been covered since yesterday, and it went down to about 60F air temp inside it overnight (20F cooler than with the blankets and cover on it).

It's still only up to around 110F even now at 2pm, adn taht's with a windbreak around it of some masonite boards in a curved "wall" jsut taller than the "tent" is. Before I put that up this morning, it didn't seem to be changing temperature at all even during the direct-sun portion of morning before it gets partly-to-mostly shaded by the trees for midday.

Now it's back in full sun and rising in air temp, but I don't think its going to actually heat teh water very much (haven't checked yet).

Due to hours cutbacks at work, I have most of this week off, so I'm gonna try to build the box for it as described in the previous post.

I was wrong about the water not heating enough: it did heat up some of it enough to give me a little bit of 105F water, enough for a shower about 3pm (when the shade from the big tree blocks most of the direct sun, and begins to also block that on hte mirror), though it was getting down close to 90F by the end of the shower.

It didn't heat up *all* the water enough, but it did heat enough for that, so it's still working well enough right now--but it does show that it's going to need that differetn configuration to increase heat gain and decrease heat loss, in order to continue working well enough as it gets colder with less and less sun each day thru the winter.

I guess I forgot to post the pics of the new pump placement, and cold water supply on the solar tank. Am presently not using the pump, but am instead using the solar tank supply directly, until I can solve the thermosiphon issue, or setup a timer on the pump to get it to shuffle water around thru the day and keep it all warm (though I don't think that will work, either, because if there were enough heat going into the water in the first place, I'd expect it to be hot enough to heat teh storage tank and it's water after pumping the heated into the cold that's in there).

The hot line on the solar tank needs to be the top most outlet. The cold return from the storage tank needs to go to the bottom most inlet on the solar tank. The hot from the solar tank gets connected to the HOT connection on the storage tank. IF you are mixing the hot with the cold, you are losing all the heat. You want to add the hot naturally to the storage tank, and allow the cold to seep kinda, out of the storage down to the solar tank.

I believe you have that hooked up correctly, but, that last photo looks like the hot outlet is halfway between top and bottom. ??

Harold in CR said:

The hot line on the solar tank needs to be the top most outlet. The cold return from the storage tank needs to go to the bottom most inlet on the solar tank. The hot from the solar tank gets connected to the HOT connection on the storage tank.

Click to expand...

Yep, that's how it's setup, with the pump at the solar tank end of the HOT connection.

IF you are mixing the hot with the cold, you are losing all the heat. You want to add the hot naturally to the storage tank, and allow the cold to seep kinda, out of the storage down to the solar tank.

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The only mixing of hot and cold is if I have to use the pump to move the hot water from solar tank to storage tank, because the storage tank is 50 gallons and the solar is only 30, so there's always going to be 2/5 of the water in that storage tank that's not nearly as hot as the incoming solar tank's water, until I can get thermosiphon working, or get the pump running on a timer for maybe 1:10 or 1:20 duty cycle or something that's just enough to keep water circulating and being warmed. .

Presently I'm not even accessing th ewater in the storage tank, because so much heat is lost (and so little captured by the solar tank) in it because fo that capacity difference.

I believe you have that hooked up correctly, but, that last photo looks like the hot outlet is halfway between top and bottom. ??

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No, that's the fresh cold inlet from the wall (pressure supply).

The hot outlet from solar to storage is on the pump, coming out radially from the whtie plastic part of it (the pumps inlet is directly connected to the hot outlet ofthe solar tank itself.