Drain Back systems of yester years

[onokai]

I have a functioning older drain back direct water system. Two 4x8 panels on roof facing south. The loop feeds a Rheem 80 gallon solar aid tank and then feeds out Rheem natural gas water heater. The drain down valve is a sunspool (factory burned down long ago) I put in this sytem in 82 if I recall maybe 83?
I got abiut 25-30 years from the 1st tank and now am on a new tank 10 years old. I have a spare tank (two years new bought off craigs list as a spare)
I have a few sunspools as backups and the contoller is a independent enery drain down controller (I have a few spare off ebay as well. I live ia sometimes freeze area in winter so the sunspool is on a electronis timer so it drains every night. I have moved this two times over the years -remodleing for one and new 50 year roof the second time.The drain down water is pumped to plants nearby. I also have a grundfus smart pump recirculating pump feeding the hot water loop off drain down valve on bottom of 40 gallon water heater so that we have instant hot water at all taps. This also has been a great system -super effencent electric wise as well. With the wester drought saving water is key as we are on a 110 foot well. Been here for 49 years now-same property.
I love thios simple efficient drain down system and have kept it up over the decades -I have gone thru a bunch of Taco curiclating pumps as well. all stainless.
On aside note we have mineral free water so I add calcite to our water at the well in a large kinetico static tank.This keeps the copper from being striped in our house plumbing. No copper green water. Also done this for 40 years now.
Nowdays solar water is with glycol systems which lose some efficientcy as its double transfer system. The direct is a great system but does require working on now and then.Plus the parts are hard to find

 

[WYtreasure]

I have a functioning older drain back direct water system. Two 4x8 panels on roof facing south. The loop feeds a Rheem 80 gallon solar aid tank and then feeds out Rheem natural gas water heater. The drain down valve is a sunspool (factory burned down long ago) I put in this sytem in 82 if I recall maybe 83?
I got abiut 25-30 years from the 1st tank and now am on a new tank 10 years old. I have a spare tank (two years new bought off craigs list as a spare)
I have a few sunspools as backups and the contoller is a independent enery drain down controller (I have a few spare off ebay as well. I live ia sometimes freeze area in winter so the sunspool is on a electronis timer so it drains every night. I have moved this two times over the years -remodleing for one and new 50 year roof the second time.The drain down water is pumped to plants nearby. I also have a grundfus smart pump recirculating pump feeding the hot water loop off drain down valve on bottom of 40 gallon water heater so that we have instant hot water at all taps. This also has been a great system -super effencent electric wise as well. With the wester drought saving water is key as we are on a 110 foot well. Been here for 49 years now-same property.
I love thios simple efficient drain down system and have kept it up over the decades -I have gone thru a bunch of Taco curiclating pumps as well. all stainless.
On aside note we have mineral free water so I add calcite to our water at the well in a large kinetico static tank.This keeps the copper from being striped in our house plumbing. No copper green water. Also done this for 40 years now.
Nowdays solar water is with glycol systems which lose some efficientcy as its double transfer system. The direct is a great system but does require working on now and then.Plus the parts are hard to find

Very cool, mineral free water is probably good for your system.
Any chance of pictures of how you make the system work well for you? I have some panels I would like to put out with just water but it gets super cold here. Last night was 24. Drain down or back is a necessity.

Welcome to the party onokai, thanks for sharing.

 

[OzSolar]

Kinda neat to reminisce about the old days of SHW. I don't think there's any domestic manufactures of any sort of solar hot water systems is there?

I've had an idea for a few years now. Still haven't had time to try it yet but will someday. I think it quite possible to wire 5 to 7 PV modules in series directly up to an standard water heater that's acting as a preheater to your standard tank. Yep, solar water heating with PV but if you could skip all of those SHW components you're better off. Overall it's the same concept in that your making hot water when the sun shines and storing it for later use.

Even better if they were the $45 dollar ~250 watt modules you find on Craigslist now and then.

EDIT: SHW - Solar Hot Water - pumping water to heat it directly or heat transfer fluid (often antifreeze) through a collector to heat potable hot water via a heat exchanger.

 

[WYtreasure]

@OzSolar Dadburnit, what's "SHW"? Yeah, I'll probably feel silly later.?

 

[OzSolar]

@OzSolar Dadburnit, what's "SHW"? Yeah, I'll probably feel silly later.?

Solar Hot Water (so you can fell silly sooner.... LOL)

You bring up a good point in that there ought to be a quick reference for all these acronyms we use. I know a lot of them and it's still pretty darn easy to get confused.

 

[WYtreasure]

Well, I hope to incorporate SHW into my greenhouse heating system. In a perfect world I can warm numerous barrels of water and keep the plants happy throughout the sub-zero temps here.

The OP has some cool threads going already, I'm going to try not to crap this one up with too many silly questions.

 

[onokai]

Very cool, mineral free water is probably good for your system.
Any chance of pictures of how you make the system work well for you? I have some panels I would like to put out with just water but it gets super cold here. Last night was 24. Drain down or back is a necessity.

Welcome to the party onokai, thanks for sharing.

Mineral free is not good as its close to distilled water and that water will rob any minerals it can -say from copper pipe . Thats what pinholes copper pipe. You need minerals in your water so it does not ron them from the metal /copper /water heater / etc.
The most effective water haeting is thermo syphon -Put the panels low and hot water rises . If its frezing at night drain doen the stytem manually with valves. Hawaii has many domestic hot water systems pre made to buy-I'm assuming the southern US does to.

 

[onokai]

One other note on the system-two years ago when I built my solar electric system- last spring I wired the Sol Arc extra power (smart load), that power that I'm not using (remember I'm a solar pirate and not selling any back to Uitilty-no permits either for that matter) That extra power is going into that Rheem 80 gallon solaraide tank that preheats the water heater. My tank came with no stinger (hot water electrci elements ). Sol Arc suggest no maore than a 3500 draw on that smart load so I put in a 3500 watt elctrci element in the tank. Now that heats the water as well as my solar roof panels (SHW). That has been in nearly a yaer now with great results. Never overheated as the indepentent energy (SHW) controller has a 180 degree shut off on that solar loop (sunspool). There are only two of us using the water sytem as well so minimal use except for water usage in the pottery studio (full time potter -45+ years now)
If we get a small hot tub I may divert this extra power to that as well as use some solar water panels I have been hoarding to heat it.

 

[Horsefly]

Around 1973 my father got a pitch for solar hot water for our farm house in Colorado. My dad was pretty sharp at engineering, so went through all the analysis and decided it was worth it. I was only 15 at the time, so didn't really pay much attention. However, I did see lots of stuff going on at the house, and I believe 4-5 really big panels go up on our garage. My only understanding was that the sun would heat up stuff in the pipes of the panels, and that would heat up some stuff in a tank that was in the old coal storage bin on in the basement on the other side of the house (we had stopped using coal some years before, so this spot was unused). It all tied into our gas water heater. Being in High School, I didn't really care, as long as I had a hot shower.

I'm pretty sure that my dad's dive into solar hot water was not a huge success, but I think it was used for a good 10 years after it was installed. Although we've never tried again at SHW, I'm pretty sure that Dad would love what we've done with solar at the cabin we were building about the same time in the 1970's, now that we have full-time electricity thanks to solar.

 

[nofossil]

One other note on the system-two years ago when I built my solar electric system- last spring I wired the Sol Arc extra power (smart load), that power that I'm not using (remember I'm a solar pirate and not selling any back to Uitilty-no permits either for that matter) That extra power is going into that Rheem 80 gallon solaraide tank that preheats the water heater. My tank came with no stinger (hot water electrci elements ). Sol Arc suggest no maore than a 3500 draw on that smart load so I put in a 3500 watt elctrci element in the tank. Now that heats the water as well as my solar roof panels (SHW). That has been in nearly a yaer now with great results. Never overheated as the indepentent energy (SHW) controller has a 180 degree shut off on that solar loop (sunspool). There are only two of us using the water sytem as well so minimal use except for water usage in the pottery studio (full time potter -45+ years now)
If we get a small hot tub I may divert this extra power to that as well as use some solar water panels I have been hoarding to heat it.

In my opinion the best control is to use a PV panel to run the pump directly. Sun goes down, pump shuts off, gravity drains the pipes to a small holding tank, which can be below an exchanger coil, or not. I haven’t done it, but I’ve seen it done. I had a batch heater once but your setup is my dream system, simple and durable. The new absorber panels are way too high tech and unreliable for me, I may build my own. Do you still have your original heat collectors?