Simple water heater?

[Helirich]

Hi all,
This maybe a stupid question, but here goes. I saw this diagram in another thread. I was thinking of building something similar.





I was thinking of making a few changes to make it very simple. First, I don't see a need for a pressure relief, air vent or freeze prevention valve. When the system is open to the water heater, the pressure relief on it should handle any over pressure. When the system is closed off, I will drain it. So the PR will not be nesessary. I will drain it whenever there is a chance of freezing. (Very rare in FL) I don't know what a vacuum breaker is.

Now for the stupid question. What happens if I don't have a pump and controller? I was thinking that if the collected is slanted, it would create a natural cerculation because of heat rising. I have to assume someone else thought of this. So why won't this work?

[Helirich]

I did some more research and found most of my answers. I still don't know what a "vacuum breaker" is.

[Mike90250]

to go "pumpless" you need the storage above the collectors so the hot water rises. The vacuum breaker helps with the daily draining for frost protection (in winter)

[ncs55]

Mike, Yes for thermosyphon and no for pumpless, I believe you are referring to thermosyphon systems. Helirich, You might look into a passive batch heater design. It seems more like what you want. Just make sure you use one way valves to prevent reverse circulation at night if you go this way.

[SunEagle]

I did some more research and found most of my answers. I still don't know what a "vacuum breaker" is.

That diagram is very close to the system I installed.

First off unless you water tank is "open top" then it is a "closed" system. When it comes to close hot water systems there is always the chance of over pressuring the piping so a pressure relief valve is a must.

The second thing about a close water system is that you can sometime create a "vacuum" when the water flows from the top to the bottom too quickly. To prevent this and to keep the tank or pipes from collapsing a device called a "vacuum breaker" is installed which allows the pressure inside the close system to equalize so the outside pressure does not collapse anything.

Trust me when I say that both the vacuum breaker and pressure relief valve are two very low cost items to protect your expensive solar thermal system.

[ncs55]

Trust me when I say that both the vacuum breaker and pressure relief valve are two very low cost items to protect your expensive solar thermal system.

So very true, and if you go with that system, buy a spare or two so that you have one handy for future replacement.

[SunEagle]

So very true, and if you go with that system, buy a spare or two so that you have one handy for future replacement.

I can agree with that statement. Especially if you have hard water. That tends to muck up the moving parts like a relief valve or circulating pump.

[J.P.M.]

I can agree with that statement. Especially if you have hard water. That tends to muck up the moving parts like a relief valve or circulating pump.

FWW, I change out the PRV's and vac. breakers about every 18 months or so.

[Helirich]

Thanks all,
You guys that have that system, do you have the pump powered with a solar panel? Did you guys buy a kit or did you piece it together? Did you guys buy or build the roof panel? I have built a water tower, so I have water pressure without power. It would be cool if I could have hot water without power. (Of course the water is warm because the tower is in the sun)

[SunEagle]

Thanks all,
You guys that have that system, do you have the pump powered with a solar panel? Did you guys buy a kit or did you piece it together? Did you guys buy or build the roof panel? I have built a water tower, so I have water pressure without power. It would be cool if I could have hot water without power. (Of course the water is warm because the tower is in the sun)

I had my system in stalled by a professional group. The pump is powered from a 115v home source but I can easily run it from a UPS system if needed.

That is a nice tower. Unfortunately my HOA would have a big problem if I tried to build something like that in my yard.

[J.P.M.]

I had my system in stalled by a professional group. The pump is powered from a 115v home source but I can easily run it from a UPS system if needed.

That is a nice tower. Unfortunately my HOA would have a big problem if I tried to build something like that in my yard.

If the HOA says you can't put it in the yard, game the system and put it on the roof.

[Helirich]

I had my system in stalled by a professional group. The pump is powered from a 115v home source but I can easily run it from a UPS system if needed.

That is a nice tower. Unfortunately my HOA would have a big problem if I tried to build something like that in my yard.

That was a year and half project. I live out in the country, so it was more of an issue to talk my wife into it than anything else. I told her it was a Gazebo for cook outs.

[J.P.M.]

That was a year and half project. I live out in the country, so it was more of an issue to talk my wife into it than anything else. I told her it was a Gazebo for cook outs.

My wife like to cook. I'll use that line next time I'm trying to talk her into some stuff. Thanx for sharing. Always looking for new material.

[ncs55]

Thanks all,
You guys that have that system, do you have the pump powered with a solar panel? Did you guys buy a kit or did you piece it together? Did you guys buy or build the roof panel? I have built a water tower, so I have water pressure without power. It would be cool if I could have hot water without power. (Of course the water is warm because the tower is in the sun)

We use the Laing for DHW pumping as well as a few other types, and there are others that run directly from a solar panel. Just make sure that the one you buy has its own built in mppt like the Laing. You can buy a kit, or just parts from a company called solarroofs.com They make a good product and I have many of their collectors installed and working great. http://laing-thermotech.com/industri...t-tab-overview

[SunEagle]

If the HOA says you can't put it in the yard, game the system and put it on the roof.

That is where my 40 sqft thermal panel is located. It can be seen from the street but no one has complained. Now a tower would get a lot more attention about as much as some tree house people have built and have gotten nasty grams stating they must take them down or else.