Pv for s/h/w..... [RE-wrenches]

Smitty smitty at aaasolar.com
Thu May 9 09:39:41 PDT 2002


Kurt, I think in some cases a diversion load is ok, but I basically agree with Tom. Solar thermal is way more cost effective. It has been a long time, 26 years, since I lived in Wisconsin, but I have had the good fortune of working with our partner, Richard Lane, running the worlds largest glycol water heating system in Green Bay for about 10 years. 5200 4x8 collectors, originally 10,000. The railroad men, I mean
engineers, goofed big time, but that's another story. My point and question to you is this, on very cold clear WI winter days, the glycol in the arrays was warm and fluid, but the glycol in the the supply and return plumbing, 3" to 14" diameter and LOTS of it, was very thick and slushy and several 10 hp pumps had a very hard time and/or could not move it. I wonder what your experience is with this situation using a pv
direct system? It would seem to me that if the incident angle to the pv is not dead on, the pump is going to run slower and may not be able to overcome the thickened glycol, although, this may not happen often enough to worry about. Thoughts? Now I have to check my frozen banana. Smitty.

sunwise at cheqnet.net wrote:

> Original Message:Tom Lane
>
> Don't use PV power to heat hot water or Einstein will roll over in his
> grave.
>
> Hey Tom,
>
> I have always agreed with you on this.  But... something got me thinking.  If a tempering tank was used, plumbed in as a pre-heat to the existing H2O heater, and a low voltage, low wattage DC heating element installed (use a cheap glass-lined electric heater for this T-tank), and something on the order of a couple hundred watts of PV wired in??
>
> If, like most folks, they were gone for the daylight hours or otherwise not using much hot water then, that little bit of PV could heat up 50 gallons of water during a sunny day.  It doesn't have to get it real hot, but if it did, a thermostat already exists on the electric H2O heater.  Any heat going in is saving BTU's on the fossil fuel end (just installing an un-insulated tempering tank will "pre-heat" some water).
>
> SDHW systems using flat-plate collectors and a closed-loop antifreeze system are expensive and labor intensive to install  They are much more efficient at heating water, but if the water gets used at night or early morning, they aren't offering any more hot water than that existing in the T-tank anyway AND they are a lot more expensive to install with more maint. and shorter operating life.
>
> Plus!, a small PV system like this could offer a little back-up electrical power in the event of a power outage if creatively wired.
>
> Smitty, Wha-da-ya think??
>
> Kurt Nelson
>
> --------------------------------------------------------------------
> mail2web - Check your email from the web at
> http://mail2web.com/ .
>
> - - - -
> To send a message: RE-wrenches at topica.com
>
> Archive of previous messages: http://www.topica.com/lists/RE-wrenches/
>
> List rules & etiquette: http://www.mrsharkey.com/wrenches/etiquete.htm
>
> Check out participant bios: www.mrsharkey.com/wrenches/index.html
>
> Hosted by Home Power magazine
>
> Moderator: michael.welch at homepower.com
>

- - - -
To send a message: RE-wrenches at topica.com

Archive of previous messages: http://www.topica.com/lists/RE-wrenches/

List rules & etiquette: http://www.mrsharkey.com/wrenches/etiquete.htm

Check out participant bios: www.mrsharkey.com/wrenches/index.html

Hosted by Home Power magazine

Moderator: michael.welch at homepower.com

==^================================================================
This email was sent to: michael.welch at homepower.com

EASY UNSUBSCRIBE click here: http://topica.com/u/?bz8Qcs.bz9JC9
Or send an email to: RE-wrenches-unsubscribe at topica.com

T O P I C A -- Register now to manage your mail!
http://www.topica.com/partner/tag02/register
==^================================================================





More information about the RE-wrenches mailing list