[RE-wrenches] Solar Combi-systems: Heat dump or Stagnate?

[Karl Schwingel]

do you mean a drainback system? they're pretty common in space heating 
systems here in the midwest.  a 4-5 panel pressurized system will do ok 
in the summer with out a huge dump load if the tank's reasonably sized, 
and the panels are tipped steep enough.

drainbacks are common where there isn't room for a huge storage tank 
(just the 80-120 for the DHW part of the system) and any extra heat goes 
into a fan coil or coil in the furnace or whatever will get it into the 
house.  in the summer when there's no heat load, the tank high limits at 
140 F or so, and then shuts off.

hot water systems are so regionally specific, that without knowing more 
of the situation, that's all I can give you.
Karl

Troy Harvey wrote:
> I'm wondering how many of you out there have installed medium sized 
> solar hot water systems (6-8 panel) that were designed to stagnate 
> during summertime over production as opposed to diverting to a heat 
> dump or radiator? The International solar agency has a couple of 
> papers that show a properly designed system should be able to stagnate 
> in a way that the boiling glycol mix vapors in the panels, purge the 
> panels of fluid, turning off the system without degrading the glycol.
>
> That doesn't seem to be a typical way to design systems in the U.S. , 
> we've usually gone to a heat dump. Does anyone have experience with this?
>
>
> Troy Harvey
> ---------------------
> Heliocentric
> 801-453-9434
> taharvey at heliocentric.org
>
>
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-- 
Karl Schwingel
NABCEP Certified Solar Thermal Installer
NorthWind Renewable Energy LLC

PO Box 723 Stevens Point, WI 54481
Karl at Northwindre.com
Cell: 715 209 0446
Fax : 715 952 4501


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