Solar Panels For Air Conditioner ??????

biznitch15biznitch15 Registered Users Posts: 7
Hello Gents, I need some info about buying a solar panel or two just for the sole purpose of powering the AC and or Heater. I am by no means an expert but i can get by with some technical terms since reading other Threads from this forum. Is it a good idea in the first place, is there many people that do this exact thing?

I'm definately not trying to buy a complete solar home system. I dont want to do grid tie and my budget is $2000. Will this Suffice? Help please!! Thanks.

Comments

  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Solar Panels For Air Conditioner ??????

    :roll: i don't mean to be mean or anything like that, but you couldn't have read very far into the forum or you'd realize this is the type of post most of us would roll our eyes on. i don't want to discourage you about going solar either, but you need to have a better understanding of how much power air conditioning or electric heating draws and what that would cost in pvs.
  • BB.BB. Super Moderators, Administrators Posts: 32,007 admin
    Re: Solar Panels For Air Conditioner ??????

    You need to look at how much power you wish to consume... Assuming you are in the SF Bay Area (Oakland?), you don't need near as much power for A/C here as you would in the central valley...

    For example, I live pretty close to you and have ~$30,000 worth of Grid Tied solar and that, during the summer, generates roughly 500 kWhrs per month ($60 worth of electricity)...

    Say, you want to run an A/C unit that can cool several rooms (in a well insulated home). Assume that it takes 20 amps @ 120 VAC... How long will 500 kWhrs run that unit?

    500,000 Watt*Hours / (20A*120V) = 208 hours per month or about 7 hours per day...

    Is that worth $30,000 (about $20k after state and fed rebates) to run a good sized room A/C unit a few months out of the year? Probably not.

    That $30k system has 20 solar panels (175 watts each) and a 3kWatt Grid Tie inverter mounted in my garage.

    Basically, $2,000 will just pay for the solar installation permit in many cities around here (some are better, some may be worse).

    And, to be honest, a Grid Tie system is the most cost effective way to drive an A/C unit. You could go off-grid, but your power will cost you, at least, 4x the cost of a grid tie system, which itself (without rebates) already costs 2x base tier pricing of PG&E ($0.12 per kWH for PGE, ~$0.25 per kWHr for Grid Tie in our area, and $1.00+ per kWhr for off grid+battery system). (note: numbers are very approximate for a "retail installed system" that has an estimated 25 year life and includes new batteries for the off-grid system).

    If you want to cool a cabin in a hot / dry climate--using a couple of solar panels plus a swamp cooler (batteries, or not--depending if you need cooling after the sun sets)--solar works nicely...

    But, to actually be cost effective, you want to use the solar power for 9-12 months out of the year... If you only use it 3 months out of the year and it sits unused for the other 9 months--many times, it would be cheaper just to use a small generator by the time you add all of the costs up.

    In the end, conservation is where you should first do your investment.

    In California, we have tiered rates, and if you use more than, roughly 1,000 kWhrs per month (for a natural gas fed home), solar grid tie can save you some money. But, as you can see, to offset 1,000 kWhrs per month is not an inexpensive system.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • biznitch15biznitch15 Registered Users Posts: 7
    Re: Solar Panels For Air Conditioner ??????

    Thanks guys, it's a lot more than i thought. Altough I wanted to Cool my entire home with the Central AC, I had figured that i can just do the Cabin example that (BB.) gave me and save money. I live in the Inland Empire North of San Diego and East of Los Angeles about 1 hour each direction. My wife and I do a great job conserving energy, last months bill was only $18 dollars and i think we only used like 154 Kwh, I think that's low? I did use the AC once last month for about an hour.

    I guess i just thought that maybe we can purchase some small solar PV off-grid System to power the AC and that way we wouldnt have to pay the electric company for using some of their power for the AC. Anyway, any other suggestions? Thanks guys!!
  • BB.BB. Super Moderators, Administrators Posts: 32,007 admin
    Re: Solar Panels For Air Conditioner ??????

    That is wonderful conservation... In our home of four, I got down to around 175 kWhrs or so a few times (we use natural gas for heating, no A/C or heavy loads, usual appliances for a 3 bedroom home). Normally it is around 200-300 kWhrs per month.

    A normal home around here is around 600 kWhrs per month (according to our power company for a similar sized home and no A/C).

    For an off-grid system, people aim at less than 100kWhrs per month energy usage... When the power usage is that small, the off-grid system costs are much smaller too.

    You could probably get away with a 1kWatt grid tie system and just about zero out your energy usage (if you are around 150kWhrs per month).

    The reason I keep talking about grid tie solar is that--it is the cheapest and more practical way to generate and consume solar power.

    There are only two major parts. The solar panels (plus mounts) and the Grid Tied inverter. Some conduit from the panels to the inverter, and some more conduit from the inverter to your AC breaker panel. And you are done.

    Trying to do this "off grid" and generating AC power--adds a whole bunch of equipment (and costs). Still the same solar panels and wiring (although, about 1/3 larger because of the losses of an off-grid inverter and storage batteries), wired to a solar charge controller--which feeds a bank of storage batteries (which need to be replaced every ~5-10 years). From the storage batteries you connect to an Off-Grid Inverter which feeds a new sub circuit panel for your off-grid loads. You may also need to wire from your utility power to charge the batteries when there is no sun. And, you may even want a generator for emergency power (always nice to have)...

    The advantage with the Grid Tie system is the electrical utility supplies regulated power for your home, and acts like a "perfect" almost infinite sized battery (can "store energy" from summer for use in the winter through "net metering"). Any reasonably sized off-grid system can only store about 3 days of power.

    There are also some very nice "hybrid" systems that have the advantages of both Grid Tied and Off Grid emergency power (plus the drawbacks of a battery bank, generator, extra costs)...

    It really depends on what you want for your home. A Grid Tied system for your home that would offset 150 kWhrs per month would be about 1.166 kW worth of solar panels and cost you somewhere around $10,000 installed (yes, you can save some money doing some work yourself, and there would be a ~$1,000 state check at this time).

    And you would sign up for net metering rate plan (1 year period). You might need to run Time of Use billing--which means your electricty will cost you $0.30 per kWhr during the day and $0.10 per kWhr at night... If you are generating power during the day--you get paid $0.30 per kWhr and at night, you buy $0.10 per kWhr...

    Unfortunately, it is a bit more complex than I said above--but it will give you some ideas of the options out there for you.

    Feel free to ask more questions, and let us know what it is you really need.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • System2System2 Posts: 6,290 admin
    Re: Solar Panels For Air Conditioner ??????

    Are you guys sure you know what you're talking about? My buddy told me he's getting a used system for $500., that will spin his meter backwards and unwind his power bill. Says it will even charge under the full moon because the ultra violet reflected off the moon is stronger than what has to travel through our atmosphere directly from the sun. There's no atmosphere on the moon to suck it up. I chose to believe he's right.
  • mike95490mike95490 Solar Expert Posts: 9,361 ✭✭✭✭✭
    Re: Solar Panels For Air Conditioner ??????
    Says it will even charge under the full moon because the ultra violet reflected off the moon is stronger than what has to travel through our atmosphere directly from the sun. There's no atmosphere on the moon to suck it up. I chose to believe he's right.

    Would you like to buy a bridge ? Or a gadget to run your car on water (it splits it to oxygen and Hydrogen) and as the engine runs, it recharges your battery. I also have seen (my cousin sells it) some refined serpent lubricant.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • BB.BB. Super Moderators, Administrators Posts: 32,007 admin
    Re: Solar Panels For Air Conditioner ??????

    Biznitch15,

    Don't take anything personal about your questions here--last couple of weeks there has been a lot of discussion about how the media misrepresents Solar Power and many fly-by-night solar equipment sales people (and manufacturers and importers) are hyping solar and selling junk...

    One was a comment by our host here (Wind-Sun admin--this forum is operated by their RE Store in Arizona):
    We get calls every day from people thinking that they can buy a $500 wind generator and turn off their grid power.

    And there was a thread a quite awhile ago about "Brown's Gas". Won't get you any where--but was a fun read.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • System2System2 Posts: 6,290 admin
    Re: Solar Panels For Air Conditioner ??????
    mike90045 wrote: »
    Would you like to buy a bridge ? Or a gadget to run your car on water (it splits it to oxygen and Hydrogen) and as the engine runs, it recharges your battery. I also have seen (my cousin sells it) some refined serpent lubricant.
    Ah,hahaha Gotcha! LOL Sorry Mike, Sometimes I'm just plain evil . LOL
    Wayne
  • biznitch15biznitch15 Registered Users Posts: 7
    Re: Solar Panels For Air Conditioner ??????

    Hey Bill, thanks. That info really helps. I hope i made sense when i explained what i wanted to do. I will definately look into grid tie.

    I like the idea of offsetting my bill . I dont forsee my wife and I ( + 1yr old son and twins on the way) to be using much electricity. My wife is a stay at home mom and throughout the day she hardly uses any electricity other than to microwave stuff here and there. The inside of ther house gets a lot of sunlight , so my wife doesnt use any lights at all. Thats why i wanted a solar panel(s) system that would allow me to run the AC a couple of hours a day, intermittently during the scorching hot days that SO-CAL has throughout the years, and of course we get plenty of sun out here.

    Some of you guys have 30k systems, I just want to power the AC although i know it consumes a lot of power, would the 10k you mentioned be enough or too much?
    I know that the meter would spin backwards during the day because my wife wouldnt any electricity, I would assume that all that backward spinning would offset itself in the evening just like you said, correct?
  • BB.BB. Super Moderators, Administrators Posts: 32,007 admin
    Re: Solar Panels For Air Conditioner ??????

    B',

    You need to look at your last 1 year power bills (some utilities put your 1-2 year usage on the web--just uses your customer ID and phone number or some such thing).

    I used the information for San Diego and this website to calculate how many watts of solar panels you would need to off set your yearly kWhr usage (based on the one number you gave). You can also look through these PDF files to get an idea graphically how things work.

    I came up with an estimate of 1.166 kWatts of solar panels and very roughly $8-$10 per peak watt installed (all costs). If you use more power other months/total year--the system would go up porportionally (2x power, 2x size).

    My own system is over sized for our current usage--I lose, roughly, $265 every year in unused electrical billing credits (1 year net metering, I pay if I used more, any positive balance is wiped off the books for the next year)... I planned on using more power for a portable A/C (wife hates hot weather) and, hopefully, a decent around town electric (or hybrid electric) vehicle.

    And, into the details. California has a very complex set of requirements for solar PV...

    First is how to qualify for the rebates, and at what level they are right now... (currently around $1.19 per PTC kW rating--about 1kW for "your system). Is going down (from a high of ~$2.80 per watt last year).

    Next is the billing plan you have now vs what is required for solar... For northern California, there are three residential plans E1, E6, and E7...

    E1 is the flat rate plan ($0.12 per kWhr all year round). E7 is a Time Of Use plan where I pay/receive $0.29 per kWhr noon-6pm Mon-Fri ("summer" 6 month period), and ~$0.09-$0.12/kWhr the rest of the time.

    E6 is a much more complex TOU plan... So complex, I am not sure anyone could actually accurately estimate their power bill (only half kidding here).

    And, depending on the tea leaves--E6 may be the plan you are required to use...

    I like E7 (no new connections in PG&E land), and would probably fall back to E1 flat rate to avoid E6--but again, depending on a whole bunch of stuff, you may not be able to use E1 either...

    That leaves E6. Which punishes mid-day to 8-9pm energy usage with higher rates. But, I don't get much solar after about 4-5pm in the summer--so cooking for dinner (lights, fan, oven, etc.) usually cannot be pushed back to cheaper rate periods. (E7, cheap rates start at 6pm).

    You may work out OK, because the higher rate costs start earlier in the day--when you do have solar to offset your evening usage--but it does make it rather hard difficult to push power usage into the 9pm to 10am weekday periods.

    And, lastly, there are base line rates... For my area, ours is set to about 300kWhrs per month... If you go above those levels, the rates go up higher (and the cheap off peak rates go up very quickly to near the costs of the peak rates when we get to near 1,000kWhrs per month). But for me (and it sounds like you)--those upper rates are never an issue.

    In the end, you have to figure out how much power you use--and for plug in 120 VAC appliances, a Kill-A-Watt meter will be your best $30 investment ever.

    Once you know how much power you need--things become much clearer.

    The whole California Solar PV structure is for you to try an zero out your power bill (in dollars). Too small of system--you may get killed by TOU billing. To large of system, you will never get credit for the amount you over generated.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • BrockBrock Solar Expert Posts: 633 ✭✭✭✭
    Re: Solar Panels For Air Conditioner ??????

    Another thing you might want to look in to is geothermal for heating and cooling. It is about twice the cost of a regular system, but should use 1/2 the energy. If you can handle on peak / off peak times you can get by at 1/4 the energy cost. The catch is you either have to drill wells or have an area 8 feet by about 300 feet to bury the loop field.

    If there is any hope of heating or cooling with solar a heat pump would be your best bet.

    But anything you can do to be more efficient will help you in the long run, better fridge, furnace, A/C, water heater, well all appliances really. Switching to compact fluorescent’s where ever your can in place of incandescent’s, adding insulation to the home. Conserving energy in the first place is a win win no matter how you slice it.
    3kw solar PV, 8 L16's, xw 5548, Honda eu2000i, iota DLS-54-13, Leaf EV, 4 ton horizontal geothermal, grid tied - Green Bay, WI
  • Solar GuppySolar Guppy Solar Expert Posts: 1,973 ✭✭✭
    Re: Solar Panels For Air Conditioner ??????

    While I personally think GeoThermal is a good technical solution, its not really any better than just adding PV cost wise ... and like PV, there are many other things like solar-hot water, insulation ect that are much quicker paybacks on the money invested

    Drilling or tenching is not cheap unless you make a DoItYourself project and then to be fair, PV is cheap with the same mind set

    Here is a link from the first page of a google search on "seer geothermal" http://dallasgreenzine.com/?p=97
  • biznitch15biznitch15 Registered Users Posts: 7
    Re: Solar Panels For Air Conditioner ??????

    Thanks, guys. This was really helpful. I will definatley be back with some more questions in the months to come. Thanks.
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