Cooling 8 Sunny Boys [RE-wrenches]

Wed Apr 7 11:17:22 PDT 2004

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Hi John,

Thanks for the tips.  I like the PV approach for sure.  But both that
and the grid power supply on timer and ambient temp thermostat
approach will give a lot of unnecessary run time on the fans.   Since
this is a tracking system, I get alot of cool spring/fall days with
full power - so the ambient thermostat is not very sensitive to the
need (and I get alot of hot hazy days at half power where it comes on
unnecessarily)

I'd still like to do it with a heat sink mountable thermostat that
could handle the 1 amp 120VAC power supply input or the 12 V PV input
to all fans (6 amps DC).  Any ideas on that?  What's the one used in
the Sunny Breeze rated at amperage wise?

Thanks,

Jeff

>
>Jeff C./Wrenches:
>
>For multiple units the centralized PS and multiple fans is probably a
>great idea to reduce costs.
>We suggest a 12 Vdc fans running at 9 Vdc to make them last longer,
>reduce power requirements, and keep things quiet.  Below 9 Vdc they may
>have trouble starting - depends on the fan.
>A 6V (18 Cell) PV module seems to work pretty well since the voltage is
>close to 9 when direct driving the fans and the Voc is high enought to
>get them started.
>If you are goign to use a larger PS running from the grid you might
>want to use a small plug in timer instead of / in addition to the temp
>switch.  On at 10:00 off at 17:00 should be more than adequate for most
>sites.
>Play with the start time and stop time since your results may vary due
>to local conditions.
>
>Best Regards,
>
>John Berdner.
>
>
>>>>  clrwater at earthlink.net 4/6/2004 11:35:41 PM >>>
>
>Hi All,
>
>Anyone out there have
>
>Before the sunny breeze was introduced, I installed 4 sunny boys with
>a cooling fan set up consisting of a tranformer-based 4 A, 12V power
>supply powering four 12 V, .6 amp ball bearing fans controlled by
>running the AC input to the power supply through a standard line
>voltage make-on-rise thermostat mounted above one of the sunny boy
>heatsinks. It also powers a fifth fan for the power shed. It's
>worked perfectly for almost 2 years.
>
>Now I'm adding 4 more sunny boys to the shed and coincidently while I
>was pondering how best to expand the system the power supply failed.
>It may have failed because the on-time is high since it senses
>ambient temp - not heat sink temp.
>
>So my options as I see it:
>
>1) Tear that all out and buy 8 sunny breezes - $700 and live with 3
>wall warts with questionable life
>2) Buy four more fans, a 50 watt solar panel and run them direct.
>$400. Concern: Fans will have short life if run during all
>sunlight hours without heat sink thermostat control.
>3) Buy a high quality solid state 8 amp power supply (like a
>MeanWell) and four more fans and either move the thermostat closer to
>the heat sink or get a heat sink thermostat rated to the AC input
>amperage and control the power supply.
>
>SO QUESTIONS:
>
>1) Does anyone know of a reliable off-the-shelf heat sink mountable
>thermostat that can handle the amperage of the input of the power
>supply (perhaps .1 amp at 240VAC or 2 amps at 120) (I've used
>standard electric water heater thermostats in the past for custom
>solar hot water systems - their double pole double throw so you can
>use one side for make on rise - Thier temp range is about right and
>surely can handle the amperage - but are really bulky and
>unprofessional looking! (and no way to cover exposed wires)
>
>2) Does anyone have experience with high reliability fans and/or
>power supplies and/or heat sink thermostats?
>
>3) Generally what do we think the life of a sunny breeze is? Is it
>the fan or the wall wart that'll fail first? How long?
>
>Any help before I go out and spend money would be most appreciated
>from such esteemed colleagues as you.
>
>Best,
>
>Jeff C.
>--
>~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>Jeff Clearwater
>Village Power Design Associates
>http://www.villagepower.com
>jeffc at villagepower.com
>Sustainable Energy & Water Solutions for Home & Village
>
>NABCEP Certified PV Installer
>
>Office: (413) 256-6777, Cell: (720)480-8455
>Fax: (413) 825-0372
>61 Baker Road
>Shutesbury, MA 01072;
>PO Box 115
>Boonville, CA 95415
>(877) 765-2784
>
>Council Member - Ecovillage Network of the Americas -
>http://www.ecovillage.org
>Advisory Board - Living Routes - Ecovillage Education -
>http://www.livingroutes.org
>Founder: Ecovillage Research, Development, and Demonstration Program:
>http://www.home.earthlink.net/~clrwater/RDD/rdd.html
>~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
>
>
>
>
>
>--
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--
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Jeff Clearwater
Village Power Design Associates
http://www.villagepower.com
jeffc at villagepower.com
Sustainable Energy & Water Solutions for Home & Village

NABCEP Certified PV Installer

Office:  (413) 256-6777,  Cell: (720)480-8455
Fax:  (413) 825-0372
61 Baker Road
Shutesbury, MA 01072;
PO Box 115
Boonville, CA  95415
(877) 765-2784

Council Member - Ecovillage Network of the Americas - http://www.ecovillage.org
Advisory Board - Living Routes - Ecovillage Education -
http://www.livingroutes.org
Founder:  Ecovillage Research, Development, and Demonstration Program:
http://www.home.earthlink.net/~clrwater/RDD/rdd.html
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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