Solar water heating? Where can i learn more?

[marcello7x]

So im interested in learning more about solar water heating. I eventually want to have radiant floor heating, and the way the garage and roof is designed i get direct sunlight from sunrise to set more or less.

Im curious what is involved, i have a basic understanding, but i like details. I may pickup a used set of solar panels off of cl, and make a hot water radiator system untill i can refinish my floor with pex tubing.

 

[Zick]

Great place to start;

http://www.builditsolar.com/

 

[Innov8tive1]

Great place to start;

http://www.builditsolar.com/

X2 some very good info there

 

[Fastback]

I would do some research on "Evacuated tube solar collectors", those things are a game changer. With the prices I am seeing these days you cant beat em. Nothing else compares.

Check Ebay for prices.

 

[lzenglish]

So im interested in learning more about solar water heating.

You can find a whole bunch of information on the Internet, and at the Library, as mentioned. I found that looking at other peoples working systems in your area, and talking with the owners of them, is some of the best information you can get, as the proof is in the pudding.

Wayne

 

[marcello7x]

Great place to start;

http://www.builditsolar.com/

I stumbled across that site before i came back and saw your post. Great info there. Even better is all the DIY plans.

Im strongly considering a closed loop system from a homemade panel directly into a cast iron radiator. Thats my plan unless through more research find a reason not too.

 

[marcello7x]

I may buy a panel if i come across a second hand one cheap tho. I rather have something that looks a little more professional on the outside of my garage.

 

[6768rogues]

Geographic location makes a big difference. Roof mounted collectors do not work worth a darn if covered with snow.

 

[ixlr8]

Geographic location makes a big difference. Roof mounted collectors do not work worth a darn if covered with snow.

This is true, but if you install them at the proper angle for max heat gain in the winter, snow is apt to slide off. My neighbor set his at the proper angle and he never has snow on his. Mine were not installed at the proper angle, even though I asked for them to be at the proper angle, and I often have snow on mine. If you need high temperature water, especially in a cold climate, then the evacuated tube collectors are better. Like if for hot water baseboard heat. But flat panel collectors give you better bang for your buck if you are just doing lower temp water like for radiant floor heating.
Here is a site I like to for solar info and parts, they are helpful folks to talk to.
http://www.radiantec.com/index.php

 

[marcello7x]

At first i wanted to stay away from evac tube because of pictures i saw of the big collector at the top. Like this one:

But after reading realized those are more of a diy cheaper solution vs the perminant residential ones like this:

I also learned that in colder climates the evac is much more efficient. Unless my new flooring quote is less than i expect[so i have have it done sooner] i'll be testing one out to heat water for a cast iron radiator or 2.

I figure next winter could be a good test of how well they work. Then i can consider if i should put a few on the house for heating our water supply and baseboards/radiators.

 

[BadgerBoilerMN]

Evac is good but for the snow thing.

You will not heat space with solar unless you are below the Mason/Dixon, have storage and super-insulate.

You may heat about half of your domestic hot water, but if it snows you will want a flat panel such as Solar Skies builds here in MN.

You should do the math - or have it done - before investing in Solar equipment.

 

[ixlr8]

Go talk to others who are using them to see what their +'s and -'s are with their systems. I have 2-20 tube evacuated collectors for my DHW, in Dec, with a full sunny day, they provide 100% of my hot water needs. If we can time the use of the hot water efficiently. Which means using the hot water during peak solar heating, 11:30-1:00. This gives it time for solar to heat the tank in the morning and reheat what we use in the afternoon to keep the electric heater from coming on. Presently we are seeing tank temps in the 180dF range daily. I am starting to think that I am going to have to cover one of the collectors in the summer to keep from over heating the tank on a regular basis. My neighbor has 4-30 tube collectors, he installed them to heat his shop. He never insulated his shop and has now run the lines to his house and they provide hot water to about 1/3 of the cast iron radiators in his house. According to him they provide about 1/2 his homes heating requirements. I think he is being a bit optimistic. Install the panels at least at a 65 degree angle and snow will be a minimum issue, flat plate or evacuated tube. But this is dependant on where you live for max collection. Do a cost/performance comparison between FP vs ET, and I will bet unless you are in the coldest area of the country. The FP collector will be your best bet from a $ point of view, especially if you are doing radiant floor heating. To heat my shop it was going to cost me $5200 to install a gas furnace, $7300 to install FP collectors and $11,500 to install ET collectors. The collectors would have provided about 80% of my heating needs, keeping the shop at 68dF. To add something more for you to think about, I may go solar electric instead for heating the shop. The solar electric system will cost about $9500 to install and then use that electricty to heat the water for the radiant floor. Then in the summer, sell the electricty back to the grid. What do you do with the excess heat from the solar water panels in the summer??