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Solar Carport
- Thread starter shark2k
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- Energy Environment Policy
Also have a look at VFX's picture where you see the vent stack. Traditional panels can be installed by simply putting jacks in like that on *any* roof, and creating a support grid, and bolting the panels to that. While comp is the easiest to deal with, most of our installations are through hard tiles these days.
johnr
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^ That article seems pretty critical of solar, but it does highlight some of the financial hurdles that if overcome would catapult solar into a leading energy source. Some counties have decided to begin offering to invest in their residents' solar systems, making it easy for anyone to get solar on their home with no upfront cost - if this was more widespread, it would help greatly.
Beautiful! I assume those are 225 W panels then? How many inverters, and what size?
My, much more modestly sized, 5.16 kW Sunpower system is going up on Wednesday.
Yes, it is 60 of the 225 W panels with 2 - 6000 W inverters at this time although we will probably be going to 7000 W inverters.
Donauker, that looks really nice. I wish we were able to see our panels that easily. We have 21 of 225 W panels with 2 - 3000m inverters. Total size of the installation is 4.725 kW, enough for a little more than half our energy needs.
Donauker you also have a really nice house. Does your system cover all of your energy needs? Or does it cover more? Or less? I'm guessing with the size that you would at least cover your energy needs.
Another question, is that single solar panel (or at least what looks like a solar panel on the left smaller section) for hot water?
-Shark2k
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Thanks for the compliment. I wish I could reach 100% of my usage but I was limited by my available unshaded roof area. Since my heat is all electric (geothermal heat pump) and a very significant amount of my driving is using electric, this system will probably only provide about 75% of my total usage. Our somewhat low average hr. per day of sun and our rather significant heating requirements here in PA make it difficult to reach zero energy on a home not designed from new with that purpose in mind.
I will have to be satisfied with the fact that all of the electric I will need to buy will be at off peak rates of 6.5 cent kW hr. (currently) and with having no other energy costs to speak of.
Yes, that is a solar hot water panel I installed about 4 years ago to provide domestic hot water.
Does the pump use that much power? I was under the impression that they were pretty efficient. Or is it because, as you said, your house is older that it does not retain the heat as well so you need to use it more than you would probably like?
Another question, if you don't mind. What is the square footage of the roof with all the solar panels? Really just wondering out of curiousity. And something else I just thought of, since you mentioned your array will only cover about 75% of your usage, how much electricty do you use a year (if you don't mind me asking)?
I love talking about this stuff but don't have many people to talk to around me about it, so sorry if I'm not asking to many questions :biggrin:.
-Shark2k
The pump is very efficient but it still uses a fair amount of electricity. The best way to express the efficiency is through before and after numbers. My home is not all that old (5 yrs.) it was just not designed with efficiency as a primary goal. The most efficient design would be a box shape, the picture above is of the back which is by far the most box shaped part and it hardly qualifies.
As a background my home was natural gas heat which is considered the most efficient, lowest cost heat outside of heat pump. It has over 4000 sq. ft. of heated area. When I switched to geothermal my annual electric cost only went up around $280, this was offset by eliminating $1600 of natural gas for an annual savings of over $1300. I would estimate between $100 and $200 in savings to be because of other changes made in the same time frame (some CFL lighting and Solar water heating).
The area of the array is 816 sq. ft. so the roof area is just a bit more. Hard to believe but that roof area was not designed to match that array!
Prior to receiving my Tesla I used around 19,000 kWh per year. This included about 4000 electric miles on my Vectrix. I expect to add between 2,000 and 3,000 kWh a year with the Tesla.
No problem with the questions. I love talking about the efficiency of electricity whenever I get a chance
Don, terrific installation!
I have a Sunpower installation also, but I think it was slightly mis-engineered.
I have 24 of the 225W panels, but only a 4000W inverter. I think normally the peak power output is only seen during a rather brief time when the sun is just right, but I get a full 4000W over most of the day. I think I'm losing a lot of my power potential. I get about 32KWH a day in the summer, but I think I might be able to do 40 or more.
Need to work on upgrading the inverter, but I don't think Sunpower sells directly to homeowners. I still have a lot of free roof area too, so maybe I need an even larger redo.
I have a Sunpower installation also, but I think it was slightly mis-engineered.
I have 24 of the 225W panels, but only a 4000W inverter. I think normally the peak power output is only seen during a rather brief time when the sun is just right, but I get a full 4000W over most of the day. I think I'm losing a lot of my power potential. I get about 32KWH a day in the summer, but I think I might be able to do 40 or more.
Need to work on upgrading the inverter, but I don't think Sunpower sells directly to homeowners. I still have a lot of free roof area too, so maybe I need an even larger redo.
I did an analysis of a commercial SunPower installation here in the Twin Cities (SolrenView™ - Spruce Tree Centre - Summary - careful, it doesn't work with Internet Explorer). The panels are rated at 36.8 kW and the inverters at 30 kW, although the inverters handle up to 36 kW before tripping. I calculated that this system loses 19% of its possible energy capture on an August day due to the undersizing of the inverters.
Temperature is the important factor here. We had a very cool August, allowing these panels to run pretty close to, or cooler than STC. The predicted peak output of the panels for this system is 42.2 kW around May 1. This is considerably more than the STC rating.
Mounted flush with a roof, things might not be as dramatic as with this installation, but still, it was enough for me to choose a 6 kW inverter for my 5.16 kW (24 * 215 W) system.
SByer
'08 #383
The Governator just signed net-feed and net-gain energy bills:
http://www.mercurynews.com/news/ci_13546308
In CA, that means any new installs should be thinking about maximizing roof area. We'll be ramping up our efficiency plans next spring to take advantage.
We've got 41 SunPower 225s on two 4k inverters. Only on the best day do either of the inverters really top out.
http://www.mercurynews.com/news/ci_13546308
In CA, that means any new installs should be thinking about maximizing roof area. We'll be ramping up our efficiency plans next spring to take advantage.
We've got 41 SunPower 225s on two 4k inverters. Only on the best day do either of the inverters really top out.
Here is another data point.
I used to use about 79 GJ of energy in a 80% efficient gas furnace just for heating each year. Now, with my heat pump (installed in 2006) I use about 26.6 GJ (7390 kWh) for heating, cooling and hot water each year.
My non-HVAC usage is about 4600 kWh/a for a total of about 12 MWh/a. The 5.16 kW PV system is expected to produce about 6100 kWh/a (it's facing SW). My roof can fit 8.8 kW, but due to the state rebate maxing out at 5 kW, I couldn't afford more.
I was thinking it probably had to do with annually, but wasn't 100% sure. Since you also think that is possible, I will continue thinking that unless J in MN states otherwise.
-Shark2k
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I have seen indications of this with my system and we will be changing out the 6K inverters for 7K inverters. I have seen a full 12kW output as early as 10:30 AM a few weeks ago, so I am certain I would be maxed out a good bit of the time when the sun is stronger.
It has been standard practice to undersize the inverter a bit due to the ridiculously optimistic rating on some panels. But it would appear that these Sunpower panels are very conservatively rated and will easily produce rated power and above.
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