Solar Water Heater

Round surface makes sense. 118 degrees on a cloudy day at the tank. Not bad (plenty hot if a good size tank). As long as snow drips off it, probably good in the winter too.

Reason I asked about the roof was leaks and hurricanes for me. We get those and a hurricane would catch it. They can break a stop sign post. It is amazing the power they have.

Great project Shane. I will let you work out the bugs and bother you for getting one going for me later hahahaha.. We get nothing but hot here (10 month or more of the year and sun all the time).

Actually I am rather impressed with the performance. Around 3 - 3:15 it cleared up and was mostly sunny this afternoon. I checked the temps at approx 5:30 and it showed 147 at the collectors and 134 at the tank. I just checked and the tank is at 137. It is 73 outside and the collector is at 94 still.

Mike, the only concern I would have with these for you would be flying debris. The "panels" themselves shouldn't create too much lift with all the gaps between tubes. The install was fairly simple, I did it all by myself (could have used 2 people to mount the panels on the pole...) My only advice would be to build your own work station.

Today was the first sunny day (at least 90% of the time) and the lower tank temp made it up to 155. Not too shabby!!!

Just a quick update for anyone interested... So far I have only had one time the hot water wasn't too hot, It was rainy all day and after my wife took her bath the hot water was only warm. I checked the tank and it was 92. Considering that we had probably used most of the hot water the night before and the 50 - 60 gallons my wife used for her bath... I still say not bad. As long as I don't have 2 days strait of all day clouds, most of the hot water should come from solar heat.

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Originally Posted by ShaneJackson

Just a quick update for anyone interested... So far I have only had one time the hot water wasn't too hot, It was rainy all day and after my wife took her bath the hot water was only warm. I checked the tank and it was 92. Considering that we had probably used most of the hot water the night before and the 50 - 60 gallons my wife used for her bath... I still say not bad. As long as I don't have 2 days strait of all day clouds, most of the hot water should come from solar heat.

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Hope it holds up when the snow comes. Still not bad figuring all the time the hot water heater is not one. Maybe flip it on for a backup at 96 or so?

Yea I am wondering how well it is going to do in a few months as well. One of the things that is affecting the performance is the fact that the house is blocking the sun on the tubes until 9:30 - 10am and then there are trees in the back that block the sun after 5:30-6:00pm. I am guessing I am loosing about 4 hours of sun (or getting 8 good hours). I am not sure how much of a difference the 4 hours would make because that is the times the sun would be at very sharp angles to the tubes anyways. I am guessing around 20% more BTU output if I had those 4 hours.

Depending on how things go this winter I may expand the system. One thing I have thought of doing was doubling the tubes and using it to heat the house as well.

Is breeding harmful bacteria that thrives in warm water (like Legionella) a concern for these types of water heating systems? Are you piping your potable water through that solar collector?

No. There is a double walled heat exchanger in the hot water storage tank. The water that circulates thru the solar collectors is isolated. This is also done so you can use antifreeze in the system.

Normally all potable water and spent within a day. Sounds like Shane's might be a sealed unit if he can add anti-freeze.

Mine WAS freon from the AC units on the house, through the hot water tank in hot pipes. I like the potable water thru the system, shower wash, maybe cook and done.

I have seen both sealed (like mine) and systems that have a tank built in above the heat tubes. They offer less heat loss due to the piping but do not have the capacity that the other systems offer. Also I dont think their tanks are insulated as good as a seperate tank (I may be wrong, but the ones i have seen dont seem to be).

I can use antifreeze but am not. I am just using plain water. I am not worried about freezing, and the system actualy has an antifreeze program in it. If it gets too cold it will turn the pump on and heat the outside pipes with the heat from the tank.

In Florida we can go either way. Not sure about up North there. So long as you save money, that is the deal. Any idea on savings and payback?

My total cost was $2842. Tax rebates were Federal 30% State 35% so total credit of 65% or 1847.30 for a net cost of $994.70. My tankless uses roughly $50 a month of gas so that is a ROI of 19.89 months.... Add back for the electrical used and I will probably be closer to the 2 year mark.

I remember reading something about antifreeze a couple pages back, and it makes sense now. So the tank is an indirect water heater? Sounds pretty slick.

I have a solar project that is on the back burner. Heard that the % difference between CU and CPVC was small, so I'm going to test both. Modified a HF tube roller to make fins, FAIL.. have to work on that one, or just bend them in the brake.

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Interesting! This thread got me reading more about solar heating. My gas tank heater is gone and I just bought a tankless a month ago but haven't installed it yet. The problem I'm having is dealing with the extremely hard water we have here. Which is why the tank heater died too. My thinking is that since heat precipitates the minerals maybe I can use a solar heater to condition the water and then filter out the minerals before it goes through the tankless. And in the summer, I may not even need to run the tankless if I configure the solar heating system right.

I see Shane has the evacuated tube design. Probably gona go with a well insulated flat plate design myself. There are no more rebates here so it's a DIY job. Jakes design looks promising and he'll be subjected to more of the same condition I'd be facing too.

In terms of the collectors here's what I'm thinking. 4x6 aluminum box, 4" deep with multiwall UV stabilized polycarbonate glazing. 1/2" EPS insulation all around and under the painted copper continuous piping. The piping will be soldered onto an aluminum sheet that'll be painted black as well. It'll be sealed and filled with a noble gas. Depending on the price I'd prefer to use xeon, krypton or Argon, in that order. What do you guys think? Anything you'd change or add?

This is a side project that'll be dictated by finances and time. Until then more google-fu and reading.

There's a bunch of interesting designs here: http://www.builditsolar.com/Projects...m#1KSolarWater

Some of the designs and implementations are intended for heating domestic hot water and/or heating the home. I bet the designs could be scaled down quite a bit and still be effective for what you're looking to do.

I'm considering something as a sort of pre-heater for my hot water heater. Not big enough to stand alone, but if the water going into the heater is already 100 degrees, then it'll almost never have to actually do anything except keep the water hot. And in my climate (Arizona), it's pretty easy to get enough sun to get SOME heating most of the year. My ROI should be really fast, especially if I don't sink more than $100 into it.

Just wanted to post a quick update:

Starting around mid Nov the sun started felling in the horizon to the point that I am getting shading by 2pm (at the worst). I have switched back to gas for now. I can cut some trees and gain 1 to 2 hours at best or start running electric backup.... Not what I was hopping... this effectively cuts 2-3 months of the year out.

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Originally Posted by ShaneJackson

Just wanted to post a quick update:

Starting around mid Nov the sun started felling in the horizon to the point that I am getting shading by 2pm (at the worst). I have switched back to gas for now. I can cut some trees and gain 1 to 2 hours at best or start running electric backup.... Not what I was hopping... this effectively cuts 2-3 months of the year out.

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We've only been getting a few hours of good sunlight around here too, even on a sunny day! In the summer, we get sun from 7am to around 5:30pm, but lately it's been from 11am to 1:30pm.

As for the solar hot water setup, I like yours a lot! My dad just removed the 2nd water (pre-heat) tank from the garage roof due to the roof leaking, so we have no more solar hot water helping to lower our bill. The first tank started to leak a while back, and I was thinking of welding the seam split so that tank could be used for solar on the hot tub. It's more of a back burner project for the future though.

Like you, we could use a trimming on our neighbor's trees (say about 12" from the base! Haha). Not only does it block out our sunlight, but we get all kinds of digital breakup while watching TV on the antenna. Especially if it's windy out!

Pics of one solar cart (losing daylight by the minute!) and the leaky stainless water (pre-heat) tank are attached. The neighbor's think we're idiots for trying to save on our household expenses...yet they complain about their $200-300 PG&E bills constantly and they're never even home!

My wife don't like the look of the solar panels and solar water heater either. But it is more of what others must think than the actual looks. I just tell her, if anyone actually knows what they are looking at, they know how expensive it is and will be envious. Personally I could care less what anyone thinks.

I think it's funny when the power goes out at night and all the neighbors are standing around in the street with their flashlights complaining about not being prepared for a power outage....Meanwhile we're watching TV or movies while PG&E is fixing the power lines. I totally with you on not caring what anyone thinks!