[Greenbuilding] new solar heating system in this country

[Vadurro, Rob, EMNRD]

We use a drainback system in our parks because our parks are largely seasonal in use, meaning, there are vast amounts of time when the system would be collecting heat and little or no use, resulting in big problems. Also, in this part of the country, we have power outages, which can also lead to big trouble. The drainback system solves these issues passively and integrally. If you don't have these problems (I would think most applications would  to some extent) then the closed loop glycol system would probably be better.

Rob Vadurro AIA, LEED AP
Park Architect
New Mexico State Parks
P.O. Box 1147
Santa Fe, NM 87505
505-476-3383
505-476-3361 (fax)
From: greenbuilding-bounces at lists.bioenergylists.org [mailto:greenbuilding-bounces at lists.bioenergylists.org] On Behalf Of Nick Pyner
Sent: Wednesday, March 14, 2012 6:44 PM
To: Green Building
Subject: Re: [Greenbuilding] new solar heating system in this country

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> [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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