differential controllers [RE-wrenches]

Tom Simko tom at skylinesolar.com
Wed Jan 8 07:53:17 PST 2003


Fellow wrenchers:
 I have installed several closed loop glycol/PV driven circ pump thermal
systems, kept it simple and let the PV control the circ pump: suns out and
the fluid moves. These systems were configured this way due to the thermal
panels being lower or equeal in height to the storage tanks and the lack of
grid power. They have worked well and are pretty much maintance free. One
draw back is in the morning there is a 1, maybe 1 1/2 degree temp drop as
measured in the storage tank due to the sun telling the circ pump to run
what can be 100 plus degree stored fluid through the ice cold panels, its
momentary, and just at start up. The storage tank temps quickly rise and the
system works great the rest of the day (40 to 45 degree rise in a 500 gallon
tank using 6 GOBI 4x8 thermal panels, and thats during the winter, about 6
hours full sun at my site, clear sky of course).

  This minor drop in temp at startup I have always considered worth the
simplicity of the closed loop/PV driven systems. I recently reconfigured my
own thermal space heating system and without really cogitating over it set
it up as a closed looper, and its working well. But, since the 6 Heliodyne
panels are, in my case, higher then the storage tank, in retrospect I should
have set it up as a drainback system and eliminated that minor temp drop at
startup. The other advantage I see over the closed loop system will be in
the summer,  in the past with the closed loopers, being too lazy to drain
them down for the summer and recharge them in the fall, I simply cover the
thermal and PV panels with  OSB/plywood and come heating season uncover them
and everything comes to life. I ran one system like this for over 15 years
and NEVER had to mess with it (didn't know about checking the PH) those
panels were bought used, sold for what I paid for them, and are still
cranking out the BTU's on a friends house. Am I correct that with the
drainback systems it is OK to simply let them idle throughout the summer
months, empty of fluid? That would be a huge advantage, not having to deal
with the end of the heating season/cover them up ritual. Plus, very rarely
snow will not melt off the PV panel soon enough to stop the thermal panels
from overheating, a drainback system will solve that also.

 As to the differential controller, all I can find are 120VAC models,
meaning my 4024SW will have to be ON all the time, I still cling to the old
habit of keeping it OFF as much as possible, even though my home system
(1200 watts PV + a 1000w Whisper H-80) keeps my batteries topped off by noon
most days, even in the winter. Nonetheless in order to keep the inverter OFF
as much as possible, especially during the long winter nights, as of now I
am planning to install a timer to turn on a small load, just sufficent to
wake the inverter, before the sun comes out, and off after it sets,
(approximated as the seasons change) ensuring the diff controller will have
AC when it needs it.

 Anyone have any other ideas as to how to keep the diff controller happy
other then just leave the inverter on all the time?

Tom Simko   
Skyline Solar   
Inkom, Idaho

      

- - - -
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.bWljaGFl
Or send an email to: RE-wrenches-unsubscribe at topica.com

TOPICA - Start your own email discussion group. FREE!
http://www.topica.com/partner/tag02/create/index2.html
==^================================================================





More information about the RE-wrenches mailing list