Re: [RE-wrenches] Two Load Questions

[Dan Fink]

Alan;

The ceiling fan problem is super tricky, and I'd be interested in what
others say. The DC ones I used to install (and have here at my place) draw
only 5 watts at low speed, and 10 watts at higher speed, with enough
circulation to be pretty effective. Might be worth a small DC power supply.
Mine have been on continuously, blowing down in the winter and up in the
summer, for over 10 years now! Wouldn't even know where to get them
anymore.
-- 
Dan Fink,
Executive Director;
Otherpower
Buckville Energy Consulting
Buckville Publications LLC
NABCEP / IREC accredited Continuing Education Providers
970.672.4342 (voicemail)

On Mon, Dec 10, 2012 at 10:42 PM, frenergy  wrote:

> **
> Alan,
>
> It seems like a full load analysis is a requirement for off-grid.
> If you're simply encouraging a customer to do a load analysis you may as
> well hand them a tail and hope they find the donkey.  Granted it's easy to
> slide on it as it represents a great deal of time and most customers don't
> really "get it". It's the most difficult part of off-grid.
>
> Fairly large?.Hmmm, 20-25 CF? I would figure 1.7 KWhr/day.
> With a freezer being a constant load and winter having less solar, of
> course your idea of having the freezer outside would help.  Though
> you're having to cool more in the summer, there is more solar to do so.
>
> Will a DC-to-DC converter run a DC freezer?
>
> Yes, I think 55 watts is a good number for the "typical" 48",
> slow-med speed AC ceiling fan.  They certainly have their place but there
> goes another 1.3 KWhrs/day as people tend to leave them on all the time.
>
>
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Re: [RE-wrenches] Two Load Questions

[William Dorsett]

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-boun...@lists.re-wrenches.org
[mailto:re-wrenches-boun...@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
  al...@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   

 

 

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Re: [RE-wrenches] Two Load Questions

[Dan Fink]

Probably very similar to what I have, Bill. They destratify air just fine
at slow 12V, and are pretty breezy at 24V.

I would NOT recommend center tapping a battery bank though, even at only 10
watts. A DC-DC converter would be far better.

Dan Fink,
Executive Director;
Otherpower
Buckville Energy Consulting
Buckville Publications LLC
NABCEP / IREC accredited Continuing Education Providers
970.672.4342 (voicemail)

On Tue, Dec 11, 2012 at 6:44 AM, William Dorsett wrote:

> 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
>
> ** **
>
>
>
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[RE-wrenches] LUX to STC conversion?

[William Dorsett]

Off the top, can anyone tell me how many lux of sunlight represent 100% of
STC? 1000 watts/sq meter?

 

Bill Dorsett

Sunwrights

1715 Leavenworth

Manhattan, KS

785/539-1956 Home/Office

 

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Re: [RE-wrenches] Two Load Questions

[penobscotsolar]

Alan,
   Ditto to Bills last post. I always require a load evaluation as it
imposes a certain amount of personal responsibility on the part of the
off grid customer. Two years from now when they call you and tell you
they think there's something wrong with their system you can take that
load form on your site visit and show them that the toaster oven,
window air conditioner, Mr. Coffee and dishwasher were noton the
original load form.
   We use Nextekpower's (formerly TCH Fanworks) DC ceiling fans in our
office and in my home. They are about 18 watts at high speed. A 48-24
volt DC to DC converter is the customers key to big energy savings here
for both the freezer and ceiling fans.
   An argument could be made that with the current price of solar panels
that it is less expensive to simply use more power than to buy a
Sunfrost freezer, but that means needing more room for panels,possibly
another charge controller, more wire, racking. etc as well.

Daryl



> Alan,
>
> It seems like a full load analysis is a requirement for off-grid.
> If you're simply encouraging a customer to do a load analysis you
> may as well hand them a tail and hope they find the donkey.
> Granted it's easy to slide on it as it represents a great deal of
> time and most customers don't really "get it". It's the most
> difficult part of off-grid.
>
> Fairly large?.Hmmm, 20-25 CF? I would figure 1.7 KWhr/day.
> With a freezer being a constant load and winter having less solar,
> of course your idea of having the freezer outside would help.
> Though you're having to cool more in the summer, there is more
> solar to do so.
>
> Will a DC-to-DC converter run a DC freezer?
>
> Yes, I think 55 watts is a good number for the "typical" 48",
> slow-med speed AC ceiling fan.  They certainly have their place
> but there goes another 1.3 KWhrs/day as people tend to leave them
> on all the time.
>
> Bill
>
>
>   - Original Message -
>   From: Allan Sindelar
>   To: RE-wrenches
>   Sent: Monday, December 10, 2012 8:12 PM
>   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
>   al...@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
>
>
>
>
>
>
>
> --
>
>
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List rules & 

Re: [RE-wrenches] LUX to STC conversion?

[Chris Mason]

Do yuo really want Lux?
The formula is 1Lux=0.001496 watts/sq. meter

Module performance is generally rated under standard test conditions (STC):
irradiance  of 1,000
W/m²,
solar spectrum  of
AM 1.5
and module temperature at 25°C.


On Tue, Dec 11, 2012 at 10:02 AM, William Dorsett
wrote:

> Off the top, can anyone tell me how many lux of sunlight represent 100% of
> STC? 1000 watts/sq meter?
>
> ** **
>
> Bill Dorsett
>
> Sunwrights
>
> 1715 Leavenworth
>
> Manhattan, KS
>
> 785/539-1956 Home/Office
>
> ** **
>
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>
>


-- 
Chris Mason
President, Comet Systems Ltd
www.cometenergysystems.com
Cell: 264.235.5670
Skype: netconcepts
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[RE-wrenches] DC, or not DC, Dat is Da question (Two Load Questions)

[Larry Crutcher, Starlight Solar Power Systems]

Why would one specify DC voltage appliances or lighting for off grid systems 
today when we have sub-buck-a-Watt PV solar power?  If you have space, you can 
make the added power that conventional AC appliances draw for very low cost. It 
could even be argued that the cost for DC items, wiring, distribution gear and 
labor will cost much more than simply adding more PV solar and staying all AC.

I don't like wasting resources and I understand old school thinking when PV 
modules were very expensive, but with high efficiency AC appliances and low 
cost inverters and PV modules, does it still make any sense? Shine some light 
on my thinking.

Larry Crutcher
Starlight Solar Power Systems





On Dec 10, 2012, at 9:12 PM, Allan Sindelar wrote:

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
al...@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



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Re: [RE-wrenches] DC, or not DC, Dat is Da question (Two Load Questions)

[Chris Daum]

The Sundanzers can be converted for AC use at the factory for a nominal
cost, and they claim it affects efficiency very little.
Chris Daum
Oasis Montana Inc.
406-777-4309
406-777-0830 fax
www.oasismontana.com 
   


  _  

From: re-wrenches-boun...@lists.re-wrenches.org
[mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Larry
Crutcher,Starlight Solar Power Systems
Sent: Tuesday, December 11, 2012 11:56 AM
To: RE-wrenches
Subject: [RE-wrenches] DC, or not DC, Dat is Da question (Two Load
Questions)


Why would one specify DC voltage appliances or lighting for off grid systems
today when we have sub-buck-a-Watt PV solar power?  If you have space, you
can make the added power that conventional AC appliances draw for very low
cost. It could even be argued that the cost for DC items, wiring,
distribution gear and labor will cost much more than simply adding more PV
solar and staying all AC. 

I don't like wasting resources and I understand old school thinking when PV
modules were very expensive, but with high efficiency AC appliances and low
cost inverters and PV modules, does it still make any sense? Shine some
light on my thinking. 

Larry Crutcher
Starlight Solar Power Systems





On Dec 10, 2012, at 9:12 PM, Allan Sindelar wrote:

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
  al...@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 






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Re: [RE-wrenches] DC, or not DC, Dat is Da question (Two Load Questions)

[Brian Mehalic]

I for one like a DC light in my inverter room.  Just sayin'...

Brian Mehalic
NABCEP Certified Solar PV Installer™ R031508-59
IREC ISPQ Certified Affiliated Instructor/PV US-0132

PV Curriculum Developer and Instructor
Solar Energy International
http://www.solarenergy.org



On Tue, Dec 11, 2012 at 2:05 PM, Chris Daum  wrote:

> **
> The Sundanzers can be converted for AC use at the factory for a nominal
> cost, and they claim it affects efficiency very little.
>
> Chris Daum
> Oasis Montana Inc.
> 406-777-4309
> 406-777-0830 fax
> www.oasismontana.com
>
>
>  --
> *From:* re-wrenches-boun...@lists.re-wrenches.org [mailto:
> re-wrenches-boun...@lists.re-wrenches.org] *On Behalf Of *Larry
> Crutcher,Starlight Solar Power Systems
> *Sent:* Tuesday, December 11, 2012 11:56 AM
> *To:* RE-wrenches
> *Subject:* [RE-wrenches] DC, or not DC, Dat is Da question (Two Load
> Questions)
>
> Why would one specify DC voltage appliances or lighting for off grid
> systems today when we have sub-buck-a-Watt PV solar power?  If you have
> space, you can make the added power that conventional AC appliances draw
> for very low cost. It could even be argued that the cost for DC items,
> wiring, distribution gear and labor will cost much more than simply adding
> more PV solar and staying all AC.
>
> I don't like wasting resources and I understand old school thinking when
> PV modules were very expensive, but with high efficiency AC appliances and
> low cost inverters and PV modules, does it still make any sense? Shine some
> light on my thinking.
>
> Larry Crutcher
> Starlight Solar Power Systems
>
>
>
>
>
>  On Dec 10, 2012, at 9:12 PM, Allan Sindelar wrote:
>
> 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*
> *al...@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* 
>
> *
> *
>
> 
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Re: [RE-wrenches] DC, or not DC, Dat is Da question (Two Load Questions)

[Kelly Larson]

The light by the inverter is the only DC appliance I routinely recommend 
nowadays in off grid homes and businesses, unless they have no backup 
generator.  If no backup, every electron counts, and there are some DC 
appliances, in that case, that can be worth the price and fuss.

Blessings,
Kelly



On Dec 11, 2012, at 10:55 AM, Larry Crutcher, Starlight Solar Power Systems 
wrote:

> Why would one specify DC voltage appliances or lighting for off grid systems 
> today when we have sub-buck-a-Watt PV solar power?  If you have space, you 
> can make the added power that conventional AC appliances draw for very low 
> cost. It could even be argued that the cost for DC items, wiring, 
> distribution gear and labor will cost much more than simply adding more PV 
> solar and staying all AC.
> 
> I don't like wasting resources and I understand old school thinking when PV 
> modules were very expensive, but with high efficiency AC appliances and low 
> cost inverters and PV modules, does it still make any sense? Shine some light 
> on my thinking.
> 
> Larry Crutcher
> Starlight Solar Power Systems
> 
> 
> 
> 
> 
> On Dec 10, 2012, at 9:12 PM, Allan Sindelar wrote:
> 
> 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
> al...@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
> 
> 
> 
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Re: [RE-wrenches] DC, or not DC, Dat is Da question (Two Load Questions)

[Jason Lerner]

Hello Larry,

I still install DC fridge/freezers in off grid systems for efficiency,  but 
also so that when the owners leave for the weekend/week/month they can turn off 
the inverter and all the associated phantom AC loads,  but the DC freezer is 
still on. When they come back, the meat in the freezer is still frozen.

Recently for a new off grid cabin we compared a Subzero 23 Cu. ft. 
fridge/freezer to a Sundanzer chest freezer and Sunfrost all fridge which is 51 
cu ft.combined.  Using nameplate yearly KWH's, retail price tags and putting 
the freezer in an outbuilding we found the sunfrost/sundanzer has 2.22 times 
more cu ft at 60% of the subzero's energy consumptionat 66% of the cost of 
the Subzero.  

Adding additional PV/wiring/CC/racking to run the Subzero was going to cost an 
additional $2500.  The contractor building the cabin brought up the point that 
the Sunfrost does stick out farther into the kitchen then an "average" fridge 
and there was going to be a cost associated with custom cabinets to match that 
depth,  possibly the same amount as adding extra PV's...

Best,

Jason Lerner
Waldron Power and Light Co.



On Dec 11, 2012, at 10:55 AM, Larry Crutcher, Starlight Solar Power Systems 
wrote:

> Why would one specify DC voltage appliances or lighting for off grid systems 
> today when we have sub-buck-a-Watt PV solar power?  If you have space, you 
> can make the added power that conventional AC appliances draw for very low 
> cost. It could even be argued that the cost for DC items, wiring, 
> distribution gear and labor will cost much more than simply adding more PV 
> solar and staying all AC.
> 
> I don't like wasting resources and I understand old school thinking when PV 
> modules were very expensive, but with high efficiency AC appliances and low 
> cost inverters and PV modules, does it still make any sense? Shine some light 
> on my thinking.
> 
> Larry Crutcher
> Starlight Solar Power Systems
> 
> 
> 
> 
> 
> On Dec 10, 2012, at 9:12 PM, Allan Sindelar wrote:
> 
> 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
> al...@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
> 
> 
> 
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Re: [RE-wrenches] DC, or not DC, Dat is Da question (Two Load Questions)

[Ray Walters]

I'd do the comparison against one of the much cheaper energy star rated 
AC models.  In my comparisons,On  the slight edge in efficiency isn't 
worth the extra cost of the DC units.  I've also had premature failures 
of DC fridges due to low voltage.  Finally using the inverter's built in 
low voltage disco keeps the batteries from getting ruined if the charge 
system is down, but loads stay on.

I lived for years with a DC fridge, and my family has no desire to go back.

Ray Walters

12/11/2012 12:54 PM, Jason Lerner wrote:

Hello Larry,

I still install DC fridge/freezers in off grid systems for efficiency, 
 but also so that when the owners leave for the weekend/week/month 
they can turn off the inverter and all the associated phantom AC 
loads,  but the DC freezer is still on. When they come back, the meat 
in the freezer is still frozen.


Recently for a new off grid cabin we compared a Subzero 23 Cu. ft. 
fridge/freezer to a Sundanzer chest freezer and Sunfrost all fridge 
which is 51 cu ft.combined.  Using nameplate yearly KWH's, retail 
price tags and putting the freezer in an outbuilding we found the 
sunfrost/sundanzer has 2.22 times more cu ft at 60% of the subzero's 
energy consumptionat 66% of the cost of the Subzero.


Adding additional PV/wiring/CC/racking to run the Subzero was going to 
cost an additional $2500.  The contractor building the cabin brought 
up the point that the Sunfrost does stick out farther into the kitchen 
then an "average" fridge and there was going to be a cost associated 
with custom cabinets to match that depth,  possibly the same amount as 
adding extra PV's...


Best,

Jason Lerner
Waldron Power and Light Co.



On Dec 11, 2012, at 10:55 AM, Larry Crutcher, Starlight Solar Power 
Systems wrote:


Why would one specify DC voltage appliances or lighting for off grid 
systems today when we have sub-buck-a-Watt PV solar power?  If you 
have space, you can make the added power that conventional AC 
appliances draw for very low cost. It could even be argued that the 
cost for DC items, wiring, distribution gear and labor will cost much 
more than simply adding more PV solar and staying all AC.


I don't like wasting resources and I understand old school thinking 
when PV modules were very expensive, but with high efficiency AC 
appliances and low cost inverters and PV modules, does it still make 
any sense? Shine some light on my thinking.


Larry Crutcher
Starlight Solar Power Systems





On Dec 10, 2012, at 9:12 PM, Allan Sindelar wrote:

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*
_Allan@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_ 

*
*


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Re: [RE-wrenches] DC, or not DC, Dat is Da question (Two Load Questions)

[Larry Crutcher, Starlight Solar Power Systems]

Hi Jason,

With respect to you, Sub Zero is an exceptional refrigerator but at 4-5 times 
the cost of conventional high efficiency refrigerator so the cost comparison is 
not really relative to most peoples choice. 

A typical efficient 25 cu ft refrigerator will draw about 400 kWh annually. 
Thats 1090 watt hours per day. That's about 250-400 watts of PV solar, 
considering location, far from $2500. The Sundanzer and Sunfrost are about 
$4600. Again, similar conventional efficient 120 volt units would cost about 
$3000. If you are only saving 34% from conventional and spending $1600 more, I 
still think conventional is the way to go considering the speciality nature and 
cost of repair of DC units. 

DC lights in the inverter/battery rooms, of course. 

This thread is probably outside the technical nature of the list so I shall 
secede. Thanks for the responses. 

Larry Crutcher
Starlight Solar Power Systems




On Dec 11, 2012, at 12:54 PM, Jason Lerner wrote:

Hello Larry,

I still install DC fridge/freezers in off grid systems for efficiency,  but 
also so that when the owners leave for the weekend/week/month they can turn off 
the inverter and all the associated phantom AC loads,  but the DC freezer is 
still on. When they come back, the meat in the freezer is still frozen.

Recently for a new off grid cabin we compared a Subzero 23 Cu. ft. 
fridge/freezer to a Sundanzer chest freezer and Sunfrost all fridge which is 51 
cu ft.combined.  Using nameplate yearly KWH's, retail price tags and putting 
the freezer in an outbuilding we found the sunfrost/sundanzer has 2.22 times 
more cu ft at 60% of the subzero's energy consumptionat 66% of the cost of 
the Subzero.  

Adding additional PV/wiring/CC/racking to run the Subzero was going to cost an 
additional $2500.  The contractor building the cabin brought up the point that 
the Sunfrost does stick out farther into the kitchen then an "average" fridge 
and there was going to be a cost associated with custom cabinets to match that 
depth,  possibly the same amount as adding extra PV's...

Best,

Jason Lerner
Waldron Power and Light Co.



On Dec 11, 2012, at 10:55 AM, Larry Crutcher, Starlight Solar Power Systems 
wrote:

> Why would one specify DC voltage appliances or lighting for off grid systems 
> today when we have sub-buck-a-Watt PV solar power?  If you have space, you 
> can make the added power that conventional AC appliances draw for very low 
> cost. It could even be argued that the cost for DC items, wiring, 
> distribution gear and labor will cost much more than simply adding more PV 
> solar and staying all AC.
> 
> I don't like wasting resources and I understand old school thinking when PV 
> modules were very expensive, but with high efficiency AC appliances and low 
> cost inverters and PV modules, does it still make any sense? Shine some light 
> on my thinking.
> 
> Larry Crutcher
> Starlight Solar Power Systems
> 
> 
> 
> 
> 
> On Dec 10, 2012, at 9:12 PM, Allan Sindelar wrote:
> 
> 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
> al...@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

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[RE-wrenches] micro v. string comparisons

[Marco Mangelsdorf]

Does anyone have any reports or data or studies that compare micro v. string
inverter performance when there's a single unshaded roof plane?  That is, a
side-by-side comparison.

 

We know that when any shading takes place that micro strings will perform
better than a series string feeding into a string inverter.

 

But how about when no shading is involved nor different orientation roof
faces?

 

Thanks,

marco

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Re: [RE-wrenches] LUX to STC conversion?

[William Dorsett]

I should’a knowd that phyxics just ain’t that simple, and now that you’ve
sent me the formula, I need to go find out what  AM1.5 means on a clear day
in Kansas with a humidity of xx%. My brain gets fuzzier an fuzzier. Thanks
Chris.

 

Bill Dorsett

Sunwrights

 

From: re-wrenches-boun...@lists.re-wrenches.org
[mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Chris Mason
Sent: Tuesday, December 11, 2012 10:32 AM
To: RE-wrenches
Subject: Re: [RE-wrenches] LUX to STC conversion?

 

Do yuo really want Lux?

The formula is 1Lux=0.001496 watts/sq. meter

 

Module performance is generally rated under standard test conditions (STC):
 irradiance of 1,000
 W/m², solar
 spectrum of
 AM 1.5 and module temperature at
25°C.

 

On Tue, Dec 11, 2012 at 10:02 AM, William Dorsett 
wrote:

Off the top, can anyone tell me how many lux of sunlight represent 100% of
STC? 1000 watts/sq meter?

 

Bill Dorsett

Sunwrights

1715 Leavenworth

Manhattan, KS

785/539-1956   Home/Office

 


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-- 
Chris Mason

President, Comet Systems Ltd

www.cometenergysystems.com

Cell: 264.235.5670

Skype: netconcepts

 

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[RE-wrenches] Pilot Hole Template

[Jesse Dahl]

Hello,

The roof I'm currently working on is not a typical roof.  The construction
is as follows:

2"x6" tongue and groove exposed inside, with 4 inches of foam (blue board)
and on top of that 3/4" plywood with asphalt shingles on top of that.

I'd like to make a template to ensure that my pilot bit doesn't wander when
I'm going through the blue board.  If I miss the beams inside, the hole or
the lag would be exposed.

Anybody run across this? Ideas?  I thought of maybe using a qucikmount
flashing, with a short section of EMT attached to help guide the bit

Thanks!

Jesse
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[RE-wrenches] Solar "PowerGrip" From OMG Roofing Products

[Gary Willett]

Esteemed Wrenches:

I was at the Midwest Roofing Contractors Association show last week in 
Grapevine TX. One of the vendors in the exhibit hall was OMG Roofing 
Products.


Have any of you used this product? 
http://olyfast.com/product-details/product/PowerGrip.html?language=en


*_Excerpt From Product Cut-Sheet_*:
/OMG PowerGrip is a roof mount system designed to secure rooftop solar 
racks and other equipment to roofs covered with thermoplastic (TPO and 
PVC) roof's membranes. PowerGrip provides a secure connection directly 
to the roof deck or structural members. Once heat welded in place, 
properly installed PowerGrips virtually eliminate rack movement and 
remain watertight. Factory fabricated PowerGrips are easy-to-install and 
can be made with any TPO or PVC membrane on the market for 100% 
compatibility with the roofing system. Since they eliminate the need to 
cut open the roof down to the deck, PowerGrips help save valuable time 
and labor. In addition, PowerGrips can be used with most solar rack 
systems currently available. /


--
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[RE-wrenches] Kee Safety "Solar Platform System"

[Gary Willett]

Esteemed Wrenches:

I was at the Midwest Roofing Contractors Association show last week in 
Grapevine TX. One of the vendors in the exhibit hall was Kee Safety 
Products.


Have any of you seen or used this 
product?http://keesafety.com/images/uploads/us/documents/(D3)ASSEMBLYSOLARplatform_NA.pdf


The platform has a covered slot through which PV modules can be hoisted 
up from the ground to the roof.

--

Regards,

Gary Willett, PE
Icarus Engineering LLC


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Re: [RE-wrenches] PV String Over-voltage

[Jeff Yago]

I purchased one of these devices from AEE Solar about 2 years ago.  It may not 
be in their current catalog but I am sure they still have info on supplier.  

It’s a temperature controlled switch in small outdoor enclosure that goes in 
line with one or more modules.  If temperature drops below low setpoint, 

An internal switch takes that module(s) out of string.  I do not remember if 
temperature is adjustable, but most likely it is set for around 5 degree F.

 

Jeff Yago

DTI Solar Inc. 

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Re: [RE-wrenches] off-grid permitting problem

[Jeff Yago]

We have a client that just had assembled on his rural property a pre-fab
modular home with  "normal" wiring and 200 amp main panel and meter base.
However, landowners around his property will not grant access for electric
utility to cross and he needs to move in ASAP.  He realizes that some day he
should be able to resolve this utility access but until then he wants us to
do an off-grid "basic" solar system with generator backup so he can at least
power lights, well pump, and basic appliances.   His budget will not allow a
fully off-grid solar system so we wanted to do reduced solar and battery
system with larger generator to fill in on bad solar days.  He does have
good solar exposure and lots of cleared land, but figures one day the solar
and generator will become a backup system to a future grid connection so
does not want to spend any more than absolutely necessary.

 

However ,this local inspector for this rural county has no experience with
solar and is expecting to see a 200 amp service connection from the utility
before allowing occupancy.  He did hint that a 100 amp service connection
may be allowed but nothing less.  I know NEC does mention that a panel does
not have to be supplied with the amount of service capacity it is rated for,
but what other code issues can I point out to get this accepted without
getting into a pis- contest?

 

Thanks,

 

Jeff Yago

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Re: [RE-wrenches] Pilot Hole Template

[Benn At DayStarSolar]

Jesse,
I can't picture how you will use the flashing and EMT as a guide?

2x6 tongue and groove? So is it laid flat (interconnecting the T&G) or is it on 
edge like a truss?

Either way, if you can establish a reference point from inside to the roof, 
then from the inside (if accessible) accurately measure the distances you want 
to hit the 'beams' (are these the 2x6s you mentioned?) and either record the 
measurements or mark them on a length of something (EMT, mounting rail, make 
marks on your tape) and transfer it to the roof. 
Make sure to note north/south on each end of your measurement 'template' while 
inside so it doesn't get switched around when you get on the roof. 
Also it might be good to confirm the measurements for each rail/row to account 
for any variances from row to row. 

Hope this helps?

benn
Sent from a 'smart' phone, with touch screen keys. Please excuse shortcuts and 
typos. 

On 2012-12-11, at 7:00 PM, Jesse Dahl  wrote:

> Hello,
> 
> The roof I'm currently working on is not a typical roof.  The construction is 
> as follows:
> 
> 2"x6" tongue and groove exposed inside, with 4 inches of foam (blue board) 
> and on top of that 3/4" plywood with asphalt shingles on top of that.
> 
> I'd like to make a template to ensure that my pilot bit doesn't wander when 
> I'm going through the blue board.  If I miss the beams inside, the hole or 
> the lag would be exposed.  
> 
> Anybody run across this? Ideas?  I thought of maybe using a qucikmount 
> flashing, with a short section of EMT attached to help guide the bit
> 
> Thanks!
> 
> Jesse
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Re: [RE-wrenches] DC, or not DC, Dat is Da question (Two Load Questions)

[toddcory]

this brings up a probably off topic subject regarding efficiency. i have always 
considered efficiency and conservation to be job one... especially on off grid 
systems... but with modules so inexpensive... does this still make sense? for 
example, i have an off grid customer who i suggested get a lorentz pump for his 
well. yes, the well produces around the same gpm as it used to, now only using 
about 15% of the power... but the cost to accomplish that was absurd, and that 
money could have been invested in more modules, which would also mean less 
winter generator run time... but manufacturing modules is not light in the 
resource consumption department either.
 
so my question is: do you other wrenches just look at the bottom line, short 
term costs for more efficient appliances compared to more modules to power the 
old inefficient gear... or do you take the added step to include embedded 
energy... and if so can you share the calculation process?
 
thanks,
 
todd
 
 
 
 
On Tuesday, December 11, 2012 10:55am, "Larry Crutcher, Starlight Solar Power 
Systems"  said:


Why would one specify DC voltage appliances or lighting for off grid systems 
today when we have sub-buck-a-Watt PV solar power?  If you have space, you can 
make the added power that conventional AC appliances draw for very low cost. It 
could even be argued that the cost for DC items, wiring, distribution gear and 
labor will cost much more than simply adding more PV solar and staying all AC.

I don't like wasting resources and I understand old school thinking when PV 
modules were very expensive, but with high efficiency AC appliances and low 
cost inverters and PV modules, does it still make any sense? Shine some light 
on my thinking.












Larry Crutcher
Starlight Solar Power Systems



On Dec 10, 2012, at 9:12 PM, Allan Sindelar wrote:

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 [http://energystar.gov] 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 [http://energystar.gov] 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:al...@positiveenergysolar.com] al...@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
[http://www.positiveenergysolar.com/] www.positiveenergysolar.com
 

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Re: [RE-wrenches] Remote relay options

[Dean T. Newberry]

  
  
Hello Howie,

I use Jackson Systems (dotCom) wireless relays.

Regards, Dean
  

  
On 12/10/2012 7:14 AM, Drake wrote:


  Reviewing the posts, I agree that wouldn't help.  
  
  At 06:16 PM 12/9/2012, you wrote:
  Then you have to find
a 600V DC
rated contactor. If you are going to use a contactor, which the
original
poster said he couldn't do, why not use the 240V AC rated, costs
about
$129 for a 30A contactor.  


On Sun, Dec 9, 2012 at 6:10 PM, Drake
<
  drake.chamber...@redwoodalliance.org> wrote:

  Why not disconnect the DC into the inverter with a Tyco
relay? 
No DC, no AC.




  
  At 10:32 AM 12/5/2012, you wrote:

  Hi All,

  
  I am looking for options for controlling a
disconnecting relay for
a
  
  grid-tied inverter.  It is a PVI5000 so 30 amp
240vAC.  I
need to
  
  disconnect it when the backup generator gets kicked on
by the
Automatic
  
  Transfer Switch when the grid goes down.  The array is
on a
garage that is
  
  several hundred feet from the house and service
entrance and ATS
and
  
  digging in a control wire for that distance won't
work.  So I
need a way
  
  to sense that the generator is putting out power and
then control
a
  
  contactor which would disconnect the inverter from the
subpanel.  I've
  
  looked for wireless and powerline control options but
I can't seem to
put
  
  together the pieces.

  
  Any ideas of the most cost effective and reliable
approach?

  
  Thanks,
  
  Howie
  
  --
  
  Howie Michaelson
  
  NABCEP Certified Solar PV Installer™

  
  Catamount Solar, LLC
  
  Renewable Energy Systems Sales and Service
  
  VT Solar Electric & Hot Water Incentive Partner
  
  
  http://www.CatamountSolar.com
  
  802-272-0004





  
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-- 
Chris Mason
President, Comet Systems Ltd
www.cometenergysystems.com

Cell: 264.235.5670
Skype: netconcepts

_

[RE-wrenches] Wind Turbine sources?

[Jeremy Rodriguez- All Solar Inc.]

With news that Southwest Windpower has layed off some of its staff and that 
they are discontinuing the Whisper line I wonder who will pick up the slack, if 
anyone!
Perhaps Bergey will make their XL.1 in 48V. 
What turbine brands can the wrenches recommend?  
Sorry if this does not pertain to this list, Michael
Jeremy
All Solar
CO, USA
Sent via BlackBerry. Sorry for typos and shorthand!
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Re: [RE-wrenches] DC, or not DC, Dat is Da question (Two Load Questions)

[Dan Fink]

Conservation = doing without it.
Efficiency = doing it but using less energy.

We really always try to avoid specing any system that's DC only, but we get
some pretty unusual requests from remote regions.

The Morningstar SureSine inverter has made most DC system designs moot. But
not all.

Dan Fink,
Executive Director;
Otherpower
Buckville Energy Consulting
Buckville Publications LLC
NABCEP / IREC accredited Continuing Education Providers
970.672.4342 (voicemail)

On Tue, Dec 11, 2012 at 10:10 PM,  wrote:

> this brings up a probably off topic subject regarding efficiency. i have
> always considered efficiency and conservation to be job one... especially
> on off grid systems...
>
--
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Re: [RE-wrenches] off-grid permitting problem

[William Miller]

Jeff:

There is a code passage that specifically states that one does not need to 
provide full rated ampacity to a service.  I am sure you can find it.


Find a way to prove, mathematically, that the system planned will provide 
adequate power.  Create or find a spreadsheet listing all appliances and 
wattages and system watt hours provided.  Dress it up, put your logo on it 
and sell it to the building department.


William Miller




At 07:52 PM 12/11/2012, you wrote:

Content-Type: multipart/alternative;
boundary="=_NextPart_000_0006_01CDD7F2.373D3CB0"
Content-Language: en-us

We have a client that just had assembled on his rural property a pre-fab 
modular home with  "normal" wiring and 200 amp main panel and meter 
base.  However, landowners around his property will not grant access for 
electric utility to cross and he needs to move in ASAP.  He realizes that 
some day he should be able to resolve this utility access but until then 
he wants us to do an off-grid "basic" solar system with generator backup 
so he can at least power lights, well pump, and basic appliances.   His 
budget will not allow a fully off-grid solar system so we wanted to do 
reduced solar and battery system with larger generator to fill in on bad 
solar days.  He does have good solar exposure and lots of cleared land, 
but figures one day the solar and generator will become a backup system to 
a future grid connection so does not want to spend any more than 
absolutely necessary.


However ,this local inspector for this rural county has no experience with 
solar and is expecting to see a 200 amp service connection from the 
utility before allowing occupancy.  He did hint that a 100 amp service 
connection may be allowed but nothing less.  I know NEC does mention that 
a panel does not have to be supplied with the amount of service capacity 
it is rated for, but what other code issues can I point out to get this 
accepted without getting into a pis- contest?


Thanks,

Jeff Yago


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Re: [RE-wrenches] Pilot Hole Template

[William Miller]

Jesse:

How are you going to avoid crushing the foam when you tighten your fasteners?

William Miller


At 06:00 PM 12/11/2012, you wrote:

Hello,

The roof I'm currently working on is not a typical roof.  The construction 
is as follows:


2"x6" tongue and groove exposed inside, with 4 inches of foam (blue board) 
and on top of that 3/4" plywood with asphalt shingles on top of that.


I'd like to make a template to ensure that my pilot bit doesn't wander 
when I'm going through the blue board.  If I miss the beams inside, the 
hole or the lag would be exposed.


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