[Greenbuilding] new solar heating system in this country

[Clarke Olsen]

   The reason to use a drain-back system is to not have the mass of fluid in the collector get so cold overnight.
The collector will, of course, be ice-cherry-cold, but it should warm-up faster when empty. I am setting up a
system where I intend to drain-back into a 1,000 gal tank, skipping the heat exchanger. 
The concrete tank is enclosed in 10"+ of foam, in the hope of year-round storage. 
   Question: What could I use to suppress possible organisms from growing in that hot, dark soup? Vinegar? Clorox? 
The water will remain in that unpressurized system: domestic heat & water will be through heat exchangers in the tank.

Clarke Olsen
373 route 203
Spencertown, NY 12165 
USA
518-392-4640
colsen at fairpoint.net




On Mar 14, 2012, at 8:43 PM, Nick Pyner wrote:

> Not to me.
>  
> I don't know anything about drain back systems but my understanding is that:
>  
> 1. If you use a closed loop glycol collector, you don't need drain back
>  
> 2, If you just use water, you drain the water and refill it the next morning - with water  , which I guess goes quite soem way to explain why people use  glycol.
>  
> In the article alluded to
>  
> 1. They don't seem to draw any distinction between open and closed loop systems.
>  
> 2. they glibly talk about an oversized heat exchanger. This may be detrimental to the heat exchanger performing its prime function - namely, exchanging heat.
>  
> 3. It seems that they must have air in the circlation system. This would be fatal to collector efficiency
>  
> 4. The actual collector must be the worst design ever. I have never actually seen a serpentine design like that in actual production. The only place where you would see anything like that is in an article showing how not to do it. 
>  
>  Even if there is no need to distinguish between open and close loop systems, and the heat exchanger is OK, and they have some secret air relief device, who on earth would take Wagner Solar seriously, when they have a collector like that? 
>  
> I don't know who the smiling guys are at the top of the page, but they could certainly do with asking some questions. Maybe they are just salesmen quoting a press handout. 
>  
> And another thing. Why would you use a second heat exchanger system for backup? Surely it is simpler to just install an electric element at the bottom of the tank like everybody else does? 
> Nick Pyner
> 
> Dee Why   NSW
> 
> -----Original Message-----
> From: greenbuilding-bounces at lists.bioenergylists.org [mailto:greenbuilding-bounces at lists.bioenergylists.org]On Behalf Of Sacie Lambertson
> Sent: Wednesday, 14 March 2012 7:06 AM
> To: Greenbuilding
> Subject: [Greenbuilding] new solar heating system in this country
> 
> This sounds very good to me:
> 
> http://www.buildinggreen.com/live/index.cfm/2012/3/13/German-Innovation-in-Solar-Water-Heating
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