DIY Solar Hot Water Tinkering

by Ben N on July 24, 2013

Yep, you got it… I’m one of those guys who learns a lot better by simply doing something rather than reading about it. Once I can get hands-on with something, it starts making more sense to me.

Guess that’s why I tend to tinker – try something out, change it, learn from it.

So when I show you this video of what I was doing with a solar panel yesterday, please keep in mind that it is NOT a final setup! No sireee-bob! Instead, it’s me getting hands-on, figuring out how to make it all work.

In fact, I’ve had a couple of solar hot water components for a while now. I’ve been collecting them as I can, and I just about have all the parts needed, except for the actual skills and confidence to hook it all up and make it happen! The other day, I met a friend of my parents, Roger, who raises chickens, has solar photovoltaic and solar hot water. He even built his own wood-fired bread and pizza oven! I was really impressed that ALL of it was D.I.Y., yet it all looked GREAT!

So, time for me to use the inspiration of seeing his work to figure out what else I have to do to start collecting some solar radiation!

I already have my solar panel mounted. It’s a 4′x10′ flat plate solar hot water panel. (Made by Gull Thermal, of Sarasota, Florida.) It’s an older panel, which I bought used for $100. It’s in good condition, with a solid extruded aluminum frame and one-inch copper pipe on both ends. I dug four holes, as deep as I could, before hitting water (my hard has a spring in the front yard!) and then put down pressure-treated 4×4 posts. I built a simple wooden frame on top of that, and then bolted the hot water panel to it.

For my pump, I ordered an “El-SID” a while back. It’s a very compact pump, which is designed to be able to run directly from a small PV panel. I connected it to the inlet end of the solar panel.

As for the PV solar panel to power it, I have several Harbor Freight 15-watt panels around, the same ones I used for the Solar-PowerWheels. I set that panel above the solar water panel, and connected the red and the black wires to the matching wires on the El-SID pump with wire nuts. The idea is that when the sun shines on the water panel, the water heats up. At the same time, the sun shines on the PV, powering the pump, and circulating the water. When the sun goes behind some clouds, the pump slows down or stops, but neither is the water panel making heat. (Same thing at night.)

It’s a REALLY simple system. For summer, and testing, it works great. I may have to make it slightly more complicated for colder months. I can imagine times in the winter when the sun would be shining but the water in the panel would be COLDER than the water in the tank in the house. I’ll have to come up with some sort of override or automated solution for that.

So, for the moment, I have a drum of water that I dragged over to the panel, acting as though it were a solar hot water tank. One hose goes from there to the  pump. On the other end, a garden hose runs from the outlet end back to that same drum of water.

Already, I learned a couple of things. The El-SID pump is NOT designed to fill the panel with water! It’s a low-pressure pump designed for closed-loop systems, NOT something appropriate for drain-back! It simply does NOT have enough oooomf to fill the panel with water. To do that, I stuck my garden hose on the pump inlet, and used my house water pressure to fill the panel. Once water was coming out the other end, the siphon weight of the output water reduces the load on the pump, and it can easily circulate the water.

The other thing I noticed is that this setup needs a check-valve. I had my hands in the tank of water on the hoses to check the flow when the sun went behind the clouds. I could feel water coming OUT the in, and in the OUT hose! Because the pump is on the low end, gravity can pull the water BACKWARDS through the panel when the pump isn’t running. Sure enough, I looked at the info that came with the pump, and it did say to “always use an easy-open check valve.”

The weather was partly sunny when I was doing all this. I tested the temperature of the panel with my trusty non-contact thermometer, and it measured about 150 degrees F before I got started. That is, the temperature of the EMPTY panel (no water in it) with the sun shining on it. Once I got the panel filled with water, it measured around 90 degrees. Unfortunately, I was doing this in the late afternoon, when the neighbor’s tree-line-shadow was encroaching on my solar access. So I wasn’t able to get a good reading of an hour or more of solar heat. Fortunately, my morning solar access is very good.

I’ll take a look at the temperatures today when the sun comes out!

Of course the other part of all of this is how to exchange the heat into the house…
A while back, I was driving past a house in the neighborhood which had some old-school style solar hot water collectors on the roof. But that day, it didn’t. They were removed, and set down on the ground in the yard. Turns out, the retiree who owned the house hadn’t used the solar setup in years, so his son-in law was taking down the solar parts to help clean up the house to sell it. Long story short, (and it’s a GOOD story, I’ll have to tell you it sometime!) I dragged the 60 gallon heat exchanger tank out of his basement, in exchange for me keeping it.

So now, I have a big solar tank in my garage, and I need to figure out how to cram it in my tiny laundry/utility room and plumb it up!

But that’s another blog entry for another time!

Take care,
-Ben

{ 2 comments… read them below or add one }

1 Chris Wilson January 14, 2017 at 7:56 pm

 G’day mate… liked the simplicity of you system. I’m trying to do something similar for my camp out in the bush (off-grid) and would like to know how to get the el-sid pump.
Can you tell me who makes them please and many retailers dont want to ship internationally.

2 admin January 15, 2017 at 8:50 am

That pump is made by Ivan Labs. It’s carried by many different renewable energy providers, especially solar hot water equipment sellers. I’m sure you can find one that will ship internationally.

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