[RE-wrenches] Two Load Questions

William Dorsett wmdorsett at sbcglobal.net
Tue Dec 11 05:44:51 PST 2012


I've used FanWorks permanent magnet DC ceiling fans and they use very little
draw and are available in 12 or 24.tap off a 48V battery bank or use a buck
converter?

http://www.thesolar.biz/RCH%20Fan%20Works%20DC%20Fans.htm

 

Doesn't spin very fast at 12V but destratifying air doesn't take much
movement.


Bill Dorsett

Manhattan, KS

 

From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Allan
Sindelar
Sent: Monday, December 10, 2012 10:12 PM
To: RE-wrenches
Subject: [RE-wrenches] Two Load Questions

 

Wrenches,
We still try to encourage prospective off grid customers to do a full load
analysis as an initial step in the system design process. To the point:

1) What is a good watt-hours/day figure to use for a typical, modern, new,
carefully chosen, fairly large conventional AC chest freezer, if kept in a
heated indoor location? Assume 65 degrees and seldom opened.

I will encourage that the freezer be located in a shaded, protected outdoor
location, in order to greatly reduce winter energy consumption, but I need a
good base figure to work with. 

The proposed system will most likely be 48Vnom, so a Sundanzer or similar DC
freezer is out.

2) Same question for a ceiling fan, for general slow circulation of winter
heat. The energystar.gov list gives relative cfm efficiency but not
wattages. Is 55W still a good figure to use as a default?


I have attached a condensed energystar.gov list for the freezers, but wonder
what other off grid Wrenches typically use. Also, I'm not sure that Wrenches
posts allow attachments, so this may not appear with my message.

Thank you,
Allan

-- 
Allan Sindelar
 <mailto:Allan at positiveenergysolar.com> Allan at positiveenergysolar.com
NABCEP Certified Photovoltaic Installer
NABCEP Certified Technical Sales Professional
New Mexico EE98J Journeyman Electrician
Founder and Chief Technology Officer
Positive Energy, Inc.
3209 Richards Lane (note new address)
Santa Fe, New Mexico 87507
505 424-1112
www.positiveenergysolar.com <http://www.positiveenergysolar.com/>  

 

 

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