Re: [RE-wrenches] DC, or not DC, Dat is Da question (Two Load Questions)
I found that over the years, the bottom line correlates pretty well with total energy concerns. I got away from DC and other super energy efficiency modes, as reliability is even more important, and non standard pumps just don't last near as long. For off grid, I usually spec Grundfos SQ pumps, as they are fairly standard, but don't have a starting surge. People won't appreciate the efficiency much when they have to replace it in a couple of years. If they're off grid, they're main focus can't be embodied energy, as they're probably driving a SUV long distances every day. Also, batteries are pretty bad, when compared to a grid tie PV system. I studied my energy usage overall, and found that off grid wasn't saving the planet, when I was driving 20K miles/ year. I moved into the city, fixed up an old home, and ride a bicycle more. My overall foot print is less than building a new efficient home out in the vanishing wilderness. I've tried it all, and that's just where I landed for now. I'm currently working on an off grid PV charging system for a customer's Chevy Volt, though, so I'm always open to new things. Ray Walters On 12/11/2012 10:10 PM, toddc...@finestplanet.com 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... 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 modulesis 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 la...@starlightsolar.com 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 energystar.gov http://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 http://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 mailto: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 http://www.positiveenergysolar.com/ * * Freezers Product List.xlsx___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org mailto:RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive:
Re: [RE-wrenches] DC, or not DC, Dat is Da question (Two Load Questions)
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 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 Freezers Product List.xlsx___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] DC, or not DC, Dat is Da question (Two Load Questions)
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 ch...@oasismontana.com 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* 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* http://www.positiveenergysolar.com/ * * Freezers Product List.xlsx ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] DC, or not DC, Dat is Da question (Two Load Questions)
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 Freezers Product List.xlsx___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] DC, or not DC, Dat is Da question (Two Load Questions)
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 Freezers Product List.xlsx___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] DC, or not DC, Dat is Da question (Two Load Questions)
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 http://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 http://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_ mailto: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_ http://www.positiveenergysolar.com/ * * Freezers Product List.xlsx___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org mailto:RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm http://www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org mailto:RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
Re: [RE-wrenches] DC, or not DC, Dat is Da question (Two Load Questions)
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 ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] DC, or not DC, Dat is Da question (Two Load Questions)
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 la...@starlightsolar.com 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 Freezers Product List.xlsx___ List sponsored by Home Power magazine List Address: [mailto:RE-wrenches@lists.re-wrenches.org] RE-wrenches@lists.re-wrenches.org Options settings: [http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org] http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org Sent from Finest Planet WebMail. ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] DC, or not DC, Dat is Da question (Two Load Questions)
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, toddc...@finestplanet.com 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... -- ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
