I was wondering if anyone had the solar hot water heater setup partnered up with your boiler. Acme boiler company makes an owb and also sells solar celled panels that power a pump and circulate water thats heated by the tubes. I have burned around 8 cords thiis winter and have had my owb running nonstop here in sw Missouri. The solar setup is arond 1400 but qualifies for a tax credit of 30 percent. I wasnt sure if it would help much in the winer but on the shoulder seasons it could be a neat thing to have. Let me know if anyone has purchased this product of something similar. thanks
Solar hot water tube setup
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maple1
Minister of Fire
I live in SW Mo and have 5 collectors on my shop. It wasn't a great year for solar, as you know. Twenty some days without sunshine.
What is the heat load of the building, and the heat output of the tubes?
I would only buy solar that has a SRCC listing and label. Which I believe the tax credit requires.
The www.solar-rating.com website will have a listing of the expected output.
You will need some insulated storage of course.
Unless you get a really good deal on the collectors, it may not have a payback. I can't imagine 1400 buys much solar power? Remember solar thermal collectors are rated in output per day, not hour. My 4X8 will produce around 15,000 BTU per day each.
tom in maine
Minister of Fire
It sounds like this is a single vacuum tube collector. Although they look cool, a single unit will not do much. Solar heating is always a function of the amount of surface area that intercepts sunlight. Is nice to have a PV powered pump.
Boil&Toil
Burning Hunk
Vacuum tube/evacuated tube collectors are not magical. Some are excellent, and many are a sham. With ANY solar system (or collector), first check the SRCC ratings - if it doesn't have one, it's a bad joke or a scam. If they seem to have one, but you can't find it at SRCC's site, something is fishy. Saw one of those on CL recently. Lousy numbers for a tubular, but they had it right in their manual - neither the rating number nor the company name showed up at SRCC...and neither "Acme" nor "Lucky" (their "partner" for this offering, according to their site) show up at SRCC. No SRCC rating, no tax credit...
At this point my default rule of thumb for bogus evacuated tube collectors is to compare output at the high differentials (D&E) per square foot of net aperture (in the rating) to a Heliodyne Gobi HT Flat plate. If the evac tube can't do better at extreme differential (and I'm granting them "per square foot", and few if any equal a Gobi HT 410 in sheer output, due to lack of area) then "evacuated tube technology" is being wasted or used as a sales gimmick only.
If you'd prefer a tubular benchmark, Apricus APC-30 or ETC-30 are a decent evacuated tube. Unfortunately the ratings don't really make sorting out which one is "best" at the moment all that easy (have to go look at them all), but they have been "decent" for a good long while, at least. Some of the Johnny-come-lately evac tubes are actually worse than flat pates over the full range. They are built to look at, to separate fools from their money, and not to perform.
And yep, those are thousands of btus per day (not hour) that the sun shines on the collector (and in heating season the "low radiation" column often applies, if the sun shines at all, for large parts of the country.) Which differential actually applies depends how low your emitters will go.
At this point my default rule of thumb for bogus evacuated tube collectors is to compare output at the high differentials (D&E) per square foot of net aperture (in the rating) to a Heliodyne Gobi HT Flat plate. If the evac tube can't do better at extreme differential (and I'm granting them "per square foot", and few if any equal a Gobi HT 410 in sheer output, due to lack of area) then "evacuated tube technology" is being wasted or used as a sales gimmick only.
If you'd prefer a tubular benchmark, Apricus APC-30 or ETC-30 are a decent evacuated tube. Unfortunately the ratings don't really make sorting out which one is "best" at the moment all that easy (have to go look at them all), but they have been "decent" for a good long while, at least. Some of the Johnny-come-lately evac tubes are actually worse than flat pates over the full range. They are built to look at, to separate fools from their money, and not to perform.
And yep, those are thousands of btus per day (not hour) that the sun shines on the collector (and in heating season the "low radiation" column often applies, if the sun shines at all, for large parts of the country.) Which differential actually applies depends how low your emitters will go.
Also interesting that flat plate collector production actually bypassed vac tubes in China last year.
There must be a high breakage rate getting the tubes across the ocean.
I've seen PRC (Peoples Republic of China) companies setting up their booths at solar shows and every single tube was broken during shipping. And they always abandon the vac tubes after the shows, not worth the shipping risk.
Troll the solar shows on the last day for all sorts of freebies. One friend ended up with 6 free PV modules one year, although the were all different sizes and look
tom in maine
Minister of Fire
Some time in the murky past (1985-88) we were the largest importer of Thermomax vacuum tube heat pipe solar collectors.
Warranty and cost made them unattractive.
We did a test with the vacuum tube and a flat plate for several months. The flat plate kept up with the vaccum tubes for DHW applications, easily.
Flat plates are repairable. Tubes are not. When you get tubes, you need to make sure they are available close by for service.
Individual tubes are usually more efficient. BUT, the net aperture--the area that actually intercepts sunlight-- is a lot less than the gross aperature--which is the
overall surface area.
Flat plates have a net aperture that is about the same as the gross one, that usually allows flat plates to perform as well or better than tubes.
Tubes look sexy, especially at trade shows. And they are fragile as Bob said.
Warranty and cost made them unattractive.
We did a test with the vacuum tube and a flat plate for several months. The flat plate kept up with the vaccum tubes for DHW applications, easily.
Flat plates are repairable. Tubes are not. When you get tubes, you need to make sure they are available close by for service.
Individual tubes are usually more efficient. BUT, the net aperture--the area that actually intercepts sunlight-- is a lot less than the gross aperature--which is the
overall surface area.
Flat plates have a net aperture that is about the same as the gross one, that usually allows flat plates to perform as well or better than tubes.
Tubes look sexy, especially at trade shows. And they are fragile as Bob said.
jebatty
Minister of Fire
Makes me wish again for a side-by-side installation of both for a test run in a real world application. The evacuated tubes at DP have very good production but nothing to compare that to.
Karl_northwind
Minister of Fire
you[re in an application up there that actually may be worth while for evac tube collectors (due to the winter climate). they're not doing preheat, and useable temps have to be in the 140 + range, if I remember right.
that said, year round, a top notch flat plate will out perform most evac tube collectors in most DHW scenarios, and the lower risk of summer overheat, drain back capability, durability and repairability win flat plate hands down for space heating in my world.
karl
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