Re: 25 kW Solar power project in Iowa.

**sparc** · 09-12-2012, 07:17 PM

I have often thought thatit should be possible to build a tracking system which is passive. Something that makes use of solar power to drive the panels. I see two possibilities, the first would be dc powered actuators which operate from their own solar panels. The second would use a gas charged actuator and some linkage. As the sun heats it up gas pressure builds and this drives the linkage to rotate the panel.

**MotorSeven** · 09-12-2012, 07:36 PM

I got news for ya...covering the panel with a blanket will NOT block all the UV getting to it. I tried that with my pond pump 135 watt panel....the pump still ran and pumped water while the panel was covered. So be careful..

**Alien** · 09-12-2012, 07:54 PM

The micro inverters are definitely the way to go and more folks in Oz are starting to utilize them. I didn't even know they existed when I installed my system and they would have been great for me as I suffer partial shading in the afternoons. I think my efficiency could have improved as much as 25 - 30 % if I had used micro inverters. I also found out too late I could have used a switching inverter that maintains supply to your home if the grid goes down. You only need a small battery backup for that.
You can see in my photo where the micro inverters would have been an asset due to shading. My sys. is 4KWh.

**Alien** · 09-12-2012, 07:57 PM

Originally Posted by sparc

I have often thought thatit should be possible to build a tracking system which is passive. Something that makes use of solar power to drive the panels. I see two possibilities, the first would be dc powered actuators which operate from their own solar panels. The second would use a gas charged actuator and some linkage. As the sun heats it up gas pressure builds and this drives the linkage to rotate the panel.

Actuators driven by the panels are available in Oz.

**Redneck in training** · 09-13-2012, 02:57 AM

Originally Posted by sparc

I have often thought thatit should be possible to build a tracking system which is passive. Something that makes use of solar power to drive the panels. I see two possibilities, the first would be dc powered actuators which operate from their own solar panels. The second would use a gas charged actuator and some linkage. As the sun heats it up gas pressure builds and this drives the linkage to rotate the panel.

The problem is the size. 25 kW system is about 170 sqm or 1820 sqft. The cost of the tracking can be amortised only if it provides more gain than can be gained by increasing number of the panels. At current cost/W it is hard to justify. It would make sense much farther north where summer days are long while the sun is big part of the day behind (north of) the panels.

Tracking system is very costly in Iowa because it has to be designed to withstand at least 160 kph or 100 mph wind.

**Redneck in training** · 09-13-2012, 03:02 AM

Originally Posted by MotorSeven

I got news for ya...covering the panel with a blanket will NOT block all the UV getting to it. I tried that with my pond pump 135 watt panel....the pump still ran and pumped water while the panel was covered. So be careful..

That is exactly why I will spend more money for microinverters.

**Domush** · 09-13-2012, 06:20 AM

Originally Posted by Redneck in training

1.) I pay more taxes than most people make per year.
2.) You are reading it wrong. My electric bill will be about $300 lower. The system will pay for itself in about 11 years.
3.) You got tax write off for your mortgage and nobody accused you for taking from neighbors or did they?
4.) Oil and gas companies get subsidies from our pockets too and they still stick it to us. Complain about that.

ah, the wild world of government subsidies. Other people are stealing from me, so I must steal from other people. Looters mentality. As long as you are less of a crook than someone you know, you feel righteous.

It's a race to see who can get the most welfare while still complaining about those "deadbeats" (read: other people) who get welfare.

Funny, I never thought of theft as an investment.

Sorry, am I not being civil enough? Thank you for making my taxes higher to offset your welfare. There now you can feel all better.

I do think it is great to see solar getting popular, but not at taxpayer expense. People requiring the addition of welfare credits in order to make the cost feasible just goes to show solar simply isn't yet meant for people who have other power options.

Right now, at rates of $0.13 per kw/ h, solar isn't an investment, it's an alternative, only the welfare check makes it pay off. Besides the green-ness, it isn't yet value added. There is very little, if any, net gain with current technology, as redneck's power output and monetary math reveals.

In other words, unless your per kilowatt costs are far higher, just steal from your neighbors and forget the array. The result is the same, just with slightly more carbon emissions and far less red tape.

Sent from my SCH-I500 using TractorByNet

**Alien** · 09-13-2012, 06:45 AM

Domush. We pay 23c KWh here in Oz. Makes solar very attractive.

**Domush** · 09-13-2012, 06:52 AM

Originally Posted by Alien

Domush. We pay 23c KWh here in Oz. Makes solar very attractive.

good point, I was limiting my comment to the power costs of rednecks area, not globally. Editing my post to reflect that..

Sent from my SCH-I500 using TractorByNet

**dave1949** · 09-13-2012, 07:26 AM

Ladia,

Last night I played around with PVWatts(ver. 2) for your general location. I found that using optimal seasonal panel angles of: (55* Nov. Dec., Jan. Feb.), (41* Mar., Sep., Oct.) and (25* Apr-Aug.) results in roughly a 5% annual gain in panel output. That is lower than I expected. It amounted to an additional 57 kWh per 1kW of system capacity per year.

Just checking

Thread Tools

Display