Couple evacuated tubes to outdoor wood boiler

[JOSH m]

Hi folks, new guy here.
I'm looking for thoughts or suggestions on my current homestead project.
We heat our home and domestic hot water with a outdoor woodboiler.( Legend 6240 with 325 gallon capacity)
I'm adding 2 Gear solar 24 tube water heaters to the wood shed roof. I'd like to heat the wood stove jacket water through the summer months and possibly into the fall/spring transition months.
Im open to suggestions on a 12v pump/PV setup to circulate water. And should I run these in series or parallel? I'm looking at 12 foot total rise on 3/4" pipe. Will 48 tubes be enough to bump 325 gallons from 120 degrees up to 150 degrees on summy North Carolina afternoons?

I currently burn wood year round with aquastat set to 175 degrees. I have a recirculating pump on my electric water heater. When temp drops to 130 degrees, the pump circulates water from water heater through a coil in the wood stove water jacket and back to the water heater. It's pretty basic using inkbird controllers, but has been working for 2 years now. I'd just like to take a few months off from burning in the summer.
Thoughts? And thanks in advance.

 

[Daddy Tanuki]

I honestly have no clue but I seem to be a lightening rod as every time I post the whole gang comes in to poke and prod at me… so consider this a good faith bump to get the conversation started. . Also you can Goto chit chat forum to help vote me off the Island as the first human sacrifice

 

[OzSolar]

I honestly have no clue but I seem to be a lightening rod as every time I post the whole gang comes in to poke and prod at me… so consider this a good faith bump to get the conversation started. . Also you can Goto chit chat forum to help vote me off the Island as the first human sacrifice

Ever heard of Cunningham's law?

 

[OzSolar]

Im open to suggestions on a 12v pump/PV setup to circulate water. And should I run these in series or parallel? I'm looking at 12 foot total rise on 3/4" pipe. Will 48 tubes be enough to bump 325 gallons from 120 degrees up to 150 degrees on sunny North Carolina afternoons?

I bet it would fine.

My 2 cents:

Solar potable water heating in the summer and milder shoulder months is pretty easy. EG: Long sunny days and no need for freeze protection.

Solar space heating in the middle of winter is an order of magnitude harder. Short cloudy days and freeze protection is a must. Of course you're relying on the wood for that time so need to talk about that much.

I'd just like to take a few months off from burning in the summer.
Thoughts? And thanks in advance.

It's a great idea.

Without knowing the BTU needs of your house and the BTU production capabilities of the solar evacuated tubes it's going to be a challenge to comment about how much space heating you're going to get but I do think you'll get all of your domestic water needs in the summer with ease.

 

[Daddy Tanuki]

see? I posit on a thread and people with more knowledge jump in... Mission accomplished!

 

[JOSH m]

Thanks all. I have started on the mounts and hope to get the plumbing going this week also. I guess I'll start with series plumbing the tube collectors. If I start pushing 200 in the boiler tank I can always pull tubes to adjust temps down.

 

[OzSolar]

I'm curious to know more about your solar collectors. Solar water heating is all but dead in the US. I didn't realize there was anything still available to purchase new. "Gear solar" didn't return anything on google. Links?

 

[Woody]

I'm curious to know more about your solar collectors. Solar water heating is all but dead in the US. I didn't realize there was anything still available to purchase new. "Gear solar" didn't return anything on google. Links?

There used to be more vendors out there but more and more people use PV solar panels to generate electricity, run a wire in to a temperature controller that heats up a thermal element in a water tank get pre-heat/hot water.

The evacuated solar tubes are more efficient/effective in grabbing those BTUs over generating electricity and then converting it back to heat. BUT, and a big but, is the expense, complexity of design, ease of implementation, ease of operation, space to put all the equipment,… all factors that you need to consider. Today with PV solar panels so much more affordable, most go the PV route. They see adding a few more PV panels the simpler/cheaper way to go. Plus fewer issues for the diy’er especially in regards to plumbing.

Here’s one vendor that has been around for years if you want to use evacuated solar tubes.

DudaDiesel - Biodiesel, Chemical & Solar Supplies, Alternative Energy Store

Duda promotes alternative energy with WVO biodiesel supplies, heat exchangers for SVO systems, solar water heaters, high grade chemicals, free informational articles, and...

www.dudadiesel.com

 

[JOSH m]

I'm curious to know more about your solar collectors. Solar water heating is all but dead in the US. I didn't realize there was anything still available to purchase new. "Gear solar" didn't return anything on google. Links?

Hey Ozsolar, yes Gear solar went out of business I believe. They were based out of South Carolina I came across these 2 units a few years ago. New in box.
Sunmaxx solar is another seller here in the US. I haven't bought from them, but did call them to ask about replacement tubes.
I think there is a standard 58mm x1800mm glass tube dimension. With different manufacturers making different internal heat pipes and aluminum heat sinks ( that are removable). With a outdoor wood boiler, most of the infrastructure is already there. I have the storage tank and heat exchange system in place. I'm fabricating the stands for these on top of a low slope shed roof that I built above my wood boiler. I plan to draw water out of the lower half of the wood boiler and pump it through the collector. Then dump it back at top of wood boiler tank.
I ordered a us solar TS5 pump rated at 3 gallons a minute and 11 foot of rise. I'll couple it to a 25W 12-18V panel which I'll mount on the roof with the tube setup. I'm hoping this will work for the summer months. I may switch to a temp differential controller with AC pump if the solar setup doesn't work out.

 

[Daddy Tanuki]

lacking any real knowledge in this discussion, is your system pressurized or open to the atmosphere?

 

[JOSH m]

lacking any real knowledge in this discussion, is your system pressurized or open to the atmosphere?

It'll be open to atmosphere non pressurized.