Solar Powered Homes

[Art Deco]

Does anyone have experience with water catchment from a solar carport? If so, any pearls of wisdom you would like to pass on? ( nb I'm asking from Australia so US regulations / brands are irrelevant)
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I already have a functional solar to grid roof installation on my small shed (12 x 7.5 m shed) , but I'm thinking about extending the roofline of the bigger shed with a solar carport - probably 3 -4 m x 25 m of panels along the solar access edge of that shed so we can park horse floats / tractors / trailers under it , charge 1/2 ev's in the future and use those ev's to power the shed ( which currently runs on it's own small independent solar )

We use exclusively tank water , so any extra catchment means more water for the vege gardens. That water isn't valuable enough to justify a separate roof under the panels for catchment, but I could probably justify gutters along the edge of the panels. The trouble is our solar installers know all about catching sunshine but nothing about catching water. Shed installers don't seem to understand the logistics of supporting solar panels...and plumbers charge more than electricians.....

As long as your panels are not mounted on asphalt shingles or other poison, it should be fine. Even runoff from metal roofs is potable, and solar panels are glass. A gutter across the bottom of an array into a rain barrel or cistern would certainly be worthwhile. I keep a small pond (200 - 300 us gal. ?) full year around from runoff.

 

[Art Deco]

This 100% solar community endured Hurricane Ian with no loss of power and minimal damage | CNN

Climate resiliency was built into the fabric of Babcock Ranch with stronger storms in mind, and Hurricane Ian was a major test.

www.cnn.com

A better article than I expected from CNN, tbh.

 

[J.R.]

As long as your panels are not mounted on asphalt shingles or other poison, it should be fine. Even runoff from metal roofs is potable, and solar panels are glass. A gutter across the bottom of an array into a rain barrel or cistern would certainly be worthwhile. I keep a small pond (200 - 300 us gal. ?) full year around from runoff.

Apparently even asphalt shingles are okay for gathering rain water for plants and vegetables.

https://www.bluebarrelsystems.com/blog/roofing-materials-for-rainwater-harvesting/#:~:text=Not%20a%20problem!,generally%20safe%20for%20rainwater%20collection.

I live on agricultural zoned land and we are required to have a dry well. I've thought about recovering some of that runoff, as it would be very easy to line part of the well. We don't have a shortage of water here, my water well is 425 feet deep with 380 feet of standing water, so collecting rain water would be for energy conservation. The dry well obviously feeds the water well through the ground, but a well pump requires a lot of energy to run.

 

[Art Deco]

Apparently even asphalt shingles are okay for gathering rain water for plants and vegetables.

https://www.bluebarrelsystems.com/blog/roofing-materials-for-rainwater-harvesting/#:~:text=Not%20a%20problem!,generally%20safe%20for%20rainwater%20collection.

I live on agricultural zoned land and we are required to have a dry well. I've thought about recovering some of that runoff, as it would be very easy to line part of the well. We don't have a shortage of water here, my water well is 425 feet deep with 380 feet of standing water, so collecting rain water would be for energy conservation. The dry well obviously feeds the water well through the ground, but a well pump requires a lot of energy to run.

When we tried some runoff from shingles, the fish died and the plants turned yellow, but it is a very small pond so any salt is a problem. And a regular well pump uses a crazy amount of power. There are solar powered 'slow pumps', that run all day on lower voltages (as long as the sun is shining), and still provide more than enough water, but crazy expensive.

 

[J.R.]

When we tried some runoff from shingles, the fish died and the plants turned yellow, but it is a very small pond so any salt is a problem. And a regular well pump uses a crazy amount of power. There are solar powered 'slow pumps', that run all day on lower voltages (as long as the sun is shining), and still provide more than enough water, but crazy expensive.

Good to know. Your canary in a coal mine test.

Yes, the well pump is expensive to run. When I was a kid my uncle's neighbor still had a hand pump in the kitchen. It was a poor farming community. A project I wanted to do and never got around to was to make a well cap with a hand pump. I thought it would help during our frequent power outages. As it is I can get emergency water out of the well with a portable pump.

 

[tomjasz]

crazy expensive.

I used solar pumps for my compost tea machine and had decent flow, but not a lot of pressure. What's your goal? I used RV pumps and found they were pretty cheap.(oops 15 years ago...)

 

[Art Deco]

I used solar pumps for my compost tea machine and had decent flow, but not a lot of pressure. What's your goal? I used RV pumps and found they were pretty cheap.(oops 15 years ago...)

12 volt RV pumps are still relatively cheap ( maybe $50? ) and are capable of pressurizing enough water for at least a decent shower, but IDK about a 50 or 100 foot lift.

 

[tomjasz]

50 or 100 foot lift.

OK, I'll shut up now....

 

[PDoz]

By cistern, do you guys just mean a water tank?

ALL our roof water is collected / stored in a 90,000 litre water tank ( corrugated galvanised / painted iron tank with a food quality liner ensuring that 20 years of watered down bird s*it can ferment in peace ) . That's our home water supply - we filter as much bird s*it as possible out of it before drinking.... Our roofs are all colorbond ( painted corrugated steel) .

My concern is not the water / bird s*it quality - I know enough microbiology to chuckle when people start discussing gut microflora diversity....

I'm more worried about any physical issues eg are there particular gutter designs to reduce the risk of water damage to the panels / magic smoke tubing ( wires) , any concerns with dissimilar metal galvanic corrosion between your typical solar panel and the average gutter material?

 

[Art Deco]

A cistern is a tank. I am not aware of any issues regarding the different metals. All the electrical circuits are sealed and weathertight, and have fuses by code when installed, so I think you are OK.

 

[Cassy0110]

I've recently installed off grid solar system Renogy 400W I have LED lights combined draw 15amps. The battery monitor shows how many hours of battery are left at the current draw. Even after days of clouds, and the monitor gets down to 30% or so, it only takes a couple of hours to bounce back to 100%. On clear days and all lights on, it would show that I have 40 hours of battery left.

 

[PDoz]

You can make an excellent solar water heater using galvanized roofing( how about an attic water heat booster, the sun is good at heating things a large percentage of our electricity is used to heat water.)

I've already got an adequate solar hot water system - evacuated tube from about 20 years ago, still doing a good job.

I was more interested in the logistics of water catchment when I extend my solar electricity array ( preparing to move to electric vehicles and charge ourselves) . nb this is our household water supply - everything from drinking to flushing the toilet. So I was interested to explore the logistics of water catchment directly from solar electricity panels - eg preferred gutter types , can the gutters be mounted directly to the panels or do they need independent supports ( 25 metres of gutter holds a lot of water during heavy rain ) . Is there a way to water seal between panels so we catch water efficiently? Any pitfalls others have experienced that we can avoid?

I realize the simplest option is just build a large metal carport for water catchment then put the panels above it. But it just feels environmentally wasteful to build a metal roof if we don't need to ( if the solar panels can be the roof itself) .

 

[PDoz]

Seems to me you are overthinking this, a pretty good water filter is not that hard to construct and if you miss a few raindropds so what , if you are going to drink that water never mind the worms, small animals and bird output, pollen put a UV treatment on there.The best use for the PV array would be for shade rather than shedding water, you could always use Mr.Musks solar shingles if they are still in production, when I build a carport or shed I always overbuild rather than building to a minimum. My last carport would easily hold any solar system I would care to put on it. If you are building a huge array I would imagine the cost of the roof itself would be a fraction of the total array.

Sure, but over thinking saves issues compared with under thinking.

eg We've just lost 40,000 litres of water and faced a $4.5 k repair bill due to a copper pipe that leaked within our concrete slab. The builders ran the pipe directly through the slab rather than in conduit, so we couldn't simply slide new pipe through the conduit. Ie $50 of conduit would have saved us $4 k if we knew 20 years ago that builder was dodgy.

re your uv suggestion - it doesn't help reduce particles, so we still get premature wear on moving parts ( taps etc) . It also doesn't help with corrosion of the copper pipes - between the rotting bird sh1t and the times we've had ash from bush fires contaminate our water....lets just say a 90,000 liter battery isn't a good idea.

One filter from our drinking water tap

 

[indianajo]

We've just lost 40,000 litres of water and faced a $4.5 k repair bill due to a copper pipe that leaked within our concrete slab. The builders ran the pipe directly through the slab rather than in conduit, so we couldn't simply slide new pipe through the conduit. Ie $50 of conduit would have saved us $4 k if we knew 20 years ago that builder was dodgy.

Every builder does it that way. The copper to iron pipe junction is inside the wall. That connection corrodes. Wife filled up her basement with city water from such a leak, 900 cuft a month since she wasn't reading her bills on autopay. I use 100 cuft a month, but she didn't ask me, she asked her son about high bills. The city condemned her house calling the water in the basement sewage. Cost $22000 to make her house livable again.

 

[PDoz]

Every builder does it that way. The copper to iron pipe junction is inside the wall. That connection corrodes. Wife filled up her basement with city water from such a leak, 900 cuft a month since she wasn't reading her bills on autopay. I use 100 cuft a month, but she didn't ask me, she asked her son about high bills. The city condemned her house calling the water in the basement sewage. Cost $22000 to make her house livable again.

Around here, the copper pipe is continuous and runs inside plastic conduit . I suspect our copper pipe was laid at the very last minute, and laid directly to avoid an extra trip into town for supplies - we had experienced heavy rain leading up to when they poured the slab which restricted access to the site . They had been dumping large blue rock as a driveway right up until the concrete truck arrived ( and getting lines of 4x4 builders utes bogged in the gloop trying to pull each other out ) . Entertaining.....

 

[J.R.]

Around here, the copper pipe is continuous and runs inside plastic conduit . I suspect our copper pipe was laid at the very last minute, and laid directly to avoid an extra trip into town for supplies - we had experienced heavy rain leading up to when they poured the slab which restricted access to the site . They had been dumping large blue rock as a driveway right up until the concrete truck arrived ( and getting lines of 4x4 builders utes bogged in the gloop trying to pull each other out ) . Entertaining.....

If it's Type K copper pipe, distinguished by green print on the actual pipe, then you couldn't have had a better grade of pipe. Type K, 3/4" pipe has a wall thickness of .065 inches and is designed for underground use. Portland cement will not corrode copper unless they used a mix containing cinder or fly-ash. that would be very uncommon for modern floor slabs.

 

[indianajo]

Portland cement will not corrode copper unless they used a mix containing cinder or fly-ash. that would be very uncommon for modern floor slabs.

The problem is between a copper pipe indoors, and a steel pipe outdoors. That makes a galvanic battery, and in water it will corrode. Wife's house was built 1953, junction in concrete wall started leaking 2016. Nothing to worry about, 63 years, right?
New pipe was put in copper from the meter. The meter is steel. I hope the plumber put some galvanic barrier at the joint. He made a special trip to MasterSupply in Louisville to get it, since he had at the job the wrong size. If not a galvanic barrier it will make a pool in the yard 64 years from now, not fill the basement with water. Interior plumbing is now Pex (plastic).

 

[6zfshdb]

Lately, around here, I see contractors using PEX pipe in poured concrete. So far, it seems to work but It's too new a practice to know if there will be problems down the road. A cheap form of insurance would be to use oversized PEX in the concrete. That way, a smaller pipe could be inserted later if there is a problem.

 

[PDoz]

Sorry for the threadjack - it sounds like building techniques vary significantly between Aus and the US , so any Re catching water from solar isn't going to apply here.

Unfortunately most local companies building solar carports are more interested in catching electricity than water, but I'll keep asking the locals and hopefully find out more.

Meanwhile, back on topic - we had an energy audit done at work recently. I was surprised they felt the time for cost neutrality on replacing halogen lights with led made +/- upgrading an infrequently used water heater made more sense than sinking those $ into solar generation. ( 3 year payback vs 6) . I suspect that has more to do with our feed in tarrifs +/- energy prices, but EMOTIONALY I want to sink the $ into solar rather than just replacing lights / water heaters.