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Novan solar hot water
By Wyomingbob, Section Remote Living Posted on Sat Apr 19, 2003 at 09:27:30 PM MST
From Reagan's first term...

...comes an orphaned solar hot water system that needs a home. I am in market for same. But having a devil of a time finding information on this system. Perhap's y'all can help.
The bulk of it is called the Novan Optimizer -- allegedly the Lexus of SHW in the early '80s. Manufactured in Boulder, CO. System consists of: four 4x8 fin-type collectors, with the pebbled glass (which I've NEVER understood). A counterflow-type heat exchanger (probably double-walled), pipe-inside-pipe variety. Grundfos circulating pumps (2) and zone valves. Fluid reservoir, approx 30" long x 12" diameter, which was said to contain an "oily substance." Now empty.
Questions:
Know anything about this system?
Have any of you heard of 'Bray oil,' apparently used in lieu of Glycol on some old systems -- especially Novans? Could I flush the system somehow & switch to Propylene Glycol?
Reckon the whole system, including two old Bradford White solar storage tanks (80 and 120 gallons) is worth $3000? Or should I go w/ a smaller, new system? (I have a hankering for the Thermomax Mazdon system w/ dual-heat-exchanger tank, but that's gonna hurt to the tune of $7000. Owwwch.)

Novan solar hot water | 2 comments (2 topical)

Re: Novan solar hot water (3.00 / 0) (#2)
by MrKyle on Tue Jul 27, 2004 at 01:14:57 PM MST

I too have a circa 1980's Novan Optimizer. Formerly, with the Bray Oil now with Propylene Glycol and was working okay. I discovered, that the fluid return from the collectors was higher than the send up on the roof, apparently so the panels would always be "topped off" for gaining heat. The problem is that when the fluid level falls the pump has to fight a vacuum in the line, and once the vacuum gets big enough, the pump won't circulate. If there is a way to bleed the air, usually at the top of the collector, let out air until fluid comes out. If all the air is out (no more hissing), and you still don't get fluid, you need more. I was told pressure should be between 15 and 25 psi.

My current problem is o-ring seals. The system has taco pumps and the seal blew about 3 weeks ago now. Taco gave me a part number for the model, but after ordering a couple and comparing them to the busted one, it was easy to see they were different sizes. I discussed this with a sales rep at my supplier, describing the pump housing. This is not a standard Taco pump it turns out and we came to the conclusion it was probably specially built as it has a pressure bell, guage, relief valve in addition to the fluid in and out. I'm waiting for a reply from Taco support to see if they have any further information about the Novan optimizer. And if anybody out there knows anything about o-ring seals, I'd appreciate hearing about it. Otherwise the whole thing will probably be pitched.

Hope you guys are having better luck than I. I suppose the new systems are better than these old ones but the payoff is still not there, at least not up here (Illinois). I wrote a computer program to capture the rough gain each day, then I found the different calculations to convert the degrees/gallons to BTU. Then I calculated the BTU to the natural gas cost and figured that I'm saving about $6 / month in the summertime. Keep in mind, mine is not the most efficient installation, but even at $10 /month, it would take about 66 years to break even on an $8000 installation. But then, there's always the possibility something is wrong with my calculation too.

If anybody wants further e-mail on this, I'm up for it at mr.kyle.t@netzero.com.

Oh, and the pebbled glass is supposed to work like tiny magnifying glasses to focus more heat on the fins or so I was told. If I were to do this now, I would go with a storage tank that has the heat exchange built in and eliminate a loop.

Re: Novan solar hot water (none / 0) (#1)
by Anonymous Hero on Mon Jun 30, 2003 at 05:29:26 PM MST

I also inherited a Novan solar hot water system about which I know nothing. Can anyone supply any info on this system or manufacturer. I don't think mine is installed (or maybe adjusted) correctly because even on hot (100 degree) clear sunny days, the bottom half of the storage tank (80 gal) does not even get up to 60 degree even with no hot water usage.

Novan solar hot water | 2 comments (2 topical)

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