[Greenbuilding] holding tank for solar hot water

[Tom Genovese]

to summarize so far:
- i like the suggestions for liners or using the concrete itself, but can anyone denounce water contacting EPS scientifically? i recall marc rosenbaum finding the stuff utterly hydrophobic. the seams concern me, but aquariums manage quite well...
- there is definitely a floor drain.
- bacteria? seems it should be a concern. have others used a fungacide?
- an immersed pipe will heat potable water. with no tank pressure, i see virtually no chance of backflow. is a need for leak detection warranted?
- the water is also planned to circulate in the water loop of a water-source heat pump. heard of very few of these systems, but seems brilliant to me...

 

Corwyn <corwyn at midcoast.com> wrote: 
On Feb 04, 2007, at 21:00, Tom Genovese wrote:

>  hi,
> i'm planning a holding tank for solar hot water - temps up to 180F, no 
> pressure. does anyone see a problem with lining a concrete box with 
> closed cell foam board exposed to the water?

I wouldn't expose the foam directly to water.  I have seen what happens 
when you do this for docks etc.  So, I recommend a liner of some sort.  
Given that, I would put the foam on the outside of the concrete, 
gaining that much more thermal mass.

Someone asked how you are going to do this with no pressure.  
Presumably, potable water goes through a heat exchanger of some sort.   
I certainly wouldn't want potable water coming from a tank with exposed 
closed cell foam.  Remember to include some method of detecting leaks.

> by the way, this is planned as a drainback system, which i think is a 
> more elegant solution to the freezing issue, if done right..

Depends on the application.   Location, climate, placement etc. all 
make a difference in these decisions.

Thank You Kindly,

Corwyn

-- 
Corwyn
Kermit didn't know the half of it...
http://www.greenfret.com/
corwyn at greenfret.com


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