View Full Version : Run HVAC on Solar power system?
11-22-2007, 11:41 AM
Has anyone run/setup HVAC to run on a solar power system? Would love to link to solar power somehow especially in storms when power can go out.
11-22-2007, 12:17 PM
Solar a/c is an idea I've been thinking about for a while. Something like a RV refrigerator , but on a larger scale. Would make sense in developing countries where power is expensive or for those who want to be less dependent on power companies.
I think back when I starting started out in hvac, I worked for 1 company that was real heavy into solar. It wasn't as Im guessing your asking about ( solar power to run a furnace in a power outtage).
It was heavily government subsidized and we were using utechtik phaze change salt in storage bins to store the heat , so you had it when you needed it.
It was real interesting seeing all the differant systems we were coming up with. We made some collectors and bought others. Controls were the same way, some we made some were bought.
Honestly I doubt any of those systems are still running that were put in around the late 70's. It was so experimental and we were always running into new problems from leaking utechtik salt containers , glare from collector glass, black paint turning white, and you name it. Everything was affected by the amount of heat it was receiving. For years afterwords you would see the colllectors removed from the buildings and houses being it was costing more to maintain them then it was worth.
Once the government subsidies went away .......... That was the end of the solar there. Your seeing that with bio fuels right now, without subsidies for farmers and producers ...... no way would they be doing it. Its a joke that will end when the subsidies go away. Just another government boonedoggle.
As far as the solar collectors that you see a lot of now, making electricity to run a house or sell back when its put back on the grid ....... I dont know, I have never really delt with it.
As far as payback , from my experiance ...... I will believe it when I see it. Im guessing its the same think, take away the subsidies and it will die. Now for us as hvac techs mantaining our own stuff , maybe it wouldn't be as losing a situation....... who knows ???????? :D
You're looking at hundreds of thousands of dollars to power a HVAC system with solar energy alone. (exception is gas furnace with ecm and no a/c or heatpump)
Solar/off grid or even grid connected solar systems are good for rural areas provided that energy demand is low.
Energy efficiency (electrical) combined with solar domestic water heating is your best option. For unconventional renewable heating, consider a wood or pellet stove. (wood stove must used sustainably harvested wood to be renewable)
11-22-2007, 01:39 PM
Our local power company will loan up to $40,000.00 interest free for 5 years to install solar photo voltaic with net metering. it costs 7 to 10 thousand dollars per peak kw. To run my 2 ton heat pump would cost a lot. Probably about 30K. If i want to run my whole house at peak load, about $100,000.00 installed.
I will wait a while. It is getting cheaper, maybe in 10 years it will make sense as power rates go up and solar comes down.
11-22-2007, 02:36 PM
Little off track but solar none the less, I was involved with an retired engineer whom had me install to his home drawn blue prints a solar roof mounted heat collection system using 4" metal weather proof ducting etc. H/Well modulating damper motors and controls to a separate plenum collector and mixing setup to maintain a constant 130' air supply etc. He had me do the relay control board on a fancy sheet of dimpled metal, I got a first hand master to student teaching about control & wiring & sequencing out of the ordeal that I still use to this day. The system also utilized a heated by solar water tube coil for heating at night with stored heat that I still can't quite remember how it actually worked and was control wired, (20 yrs ago)! I also installed a 100,000 BTU LP gas heater used for backup. Some 5 yrs later he called and his draft fan motor was seized up from "no use". He replaced it to still have a backup just in case. I asked him why he had not marketed the system? His reply was " son the Fed's in bed with manufactures and energy companies don't want free heat or cooling out of the bag". This guy had been getting free heat and hot water with no use of back up for years!
11-22-2007, 06:34 PM
[QUOTE=amd;1680954]You're looking at hundreds of thousands of dollars to power a HVAC system with solar energy alone. (exception is gas furnace with ecm and no a/c or heatpump)QUOTE]
Better check your math!
My brothers home is 100% solar powered, off the grid, I did the solar install. He now realizes that not putting in central AC was a mistake. There are many summer days when the batteries go to full charge and the panels just disconnect and do nothing. Sure would have been nice to use that excess power to cool the house! That system would have to be carefully selected, sized and set up but can be done.
11-23-2007, 11:45 AM
Thanks everyone! I thought we were more advanced these days in solar, but sounds like that's a no. We are rural/suburban fringe so see alot of rooftop solar and occasional earthberm houses so had hoped for opptys to be "efficient".
11-23-2007, 02:31 PM
I'll look for the link again. But someone has solar powered A/C out. I don't think its for power outages though.
11-23-2007, 02:37 PM
11-24-2007, 04:42 PM
i think the in rush current alone needs to be addressed with b4 any thing else...i think you,d need 1 hefty flux capacitor 4 it to work...no seriously.
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