[RE-wrenches] Oversizing Solar Hot Water Storage?

[August Goers]

Carl -

Thanks for the input, this is very helpful and along the lines of what I was expecting. As you eluded to below, there are so many ways to skin the cat with solar hot water so I'm interested in hearing all sides of the story.

Does anyone out there have experience with oversized tanks lacking Carl's control scheme?

-August


 August Goers


Luminalt Energy Corporation
4000 Irving Street 
San Francisco, CA 94122


Office:  415.564.7652
Mobile:  415.559.1525
august at luminalt.com
www.luminalt.com





________________________________
From: Carl Adams <swingjunkie at gmail.com>
To: RE-wrenches <re-wrenches at lists.re-wrenches.org>
Sent: Saturday, January 31, 2009 5:19:24 AM
Subject: Re: [RE-wrenches] Oversizing Solar Hot Water Storage?

August,

Your assumption about oversizing the storage is correct, too much storage and the desired usage temperature will not be reached.  Along with upsizing the storage you must change the design and control mechanism to allow priority loading of multiple storage tanks.
Load tank 1 till your desired usage setpoint is reached then begin loading storage tank2 (assuming heat is available) , then tank 3 etc.  Plumbing the tanks in series on the DHW side will allow you to draw from the warmest tank in the string.  The Resol BS Plus controller supports such a loading scheme natively, you might download that controller manual and have a look.  I'm sure this is one of only many possibilities.

With Regards
Carl


On Fri, Jan 30, 2009 at 6:06 PM, August Goers <august at luminalt.com> wrote:

Hi Solar Hot Water Wrenches –
 
Does anyone have experience or references
to the results of over sizing solar hot water storage tanks? We've been
approached on several instances to add additional storage (beyond the normal 1
to 2 gallons/ft^2 of collector size) to help bump up the solar fraction. I can
imagine that a grossly oversized storage tank could just simply never get very
warm or that the standby losses would be excessively large but I'm
looking for some more specific data and information.
 
Any info or opinions would help.
 
Thanks, August
 
August
Goers
 
 
Luminalt Energy Corporation
O:  415.564.7652
M:  415.559.1525
F:   650.244.9167
www.luminalt.com
august at luminalt.com
 
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