Solar Heat Collector SHC1.0

Solar Heat CollectorI went to visit uncle Ted's camp site last week and he showed me his out door shower, which used a coil of black garden hose coiled up on the top of the shed as his solar hot water collector. He showed that just the hot water valve turned on would burn you so he adjusted the cold water valve to get a nice temperature and proceeded to take a 15 min shower with his dog and then it was my turn. I tried to take as much time as I could to see when the hot water would run out ! but to my surprise it never did.

Seeing this with my own eyes made think back to a few of my older projects that were never completed and I think really deserve another look.

Here are 2 links to previous experiments:
Solar Heating Panel SHP1
Solar Heating System SHS 1

The first thing is the solar heat collector, I have 2 nice thermo glass patio doors that I can use for the panel along with PEX and fittings all painted black and with a nice reflective backing should work just fine.

First I did some actual testing, I used a 30 foot black garden hose with a 10 gallon drum to hold water and a small 12 volt circulation pump. I laid out the hose it's entire length along the driveway with the two ends going to the drum which was located out of the sunlight, then the circulation pumps intake was put into the drum and output was connected to one end of the hose with with the other end going back into the drum.
The starting temperature of the water in the drum was 16 degrees centigrade and in just three hours the water temperature rose to 42 degrees, I found that to be quite impressive.

Now if you live in a country where the temperature never drops below 0c or 32f this panel would do just fine but unfortunately I live in canada and it gets cold up here in the winter time so having water in the solar collector at night is not a good idea.

Solution #1:
Dont use the solar heat collector in winter.

Solution #2:
Using the available heat in your house, a small vent hole could be passed into the back of the solar collector where the warm air could circulate with-in the collector and not allow the water to freeze. Of course this would mean a small amount of heat loss within your home and it wouldn't work if the panel was sitting on a non heated structure.

Solution #3:
Using a heat exchanger and adding salt or anti-freeze to the water so it won't freeze then closing the loop and use the heat exchanger to heat up drinkable water.

Building The Collector:
Originally I was going to use 3/4" to 1/2" brass PEX Tee's but I found plastic Tee's which were much easier to cut and allow for less distance between each 1/2" PEX tubes, instead of 90 feet of PEX tubing or 15 rows I can now fit 108 feet or 18 rows. I simply cut off a 1/2 inch of plastic off each sides of 3/4" Pex Tee's, you can see the difference in picture number 3 on the right hand side, the top one is uncut and the bottom one cut to size.

In this picture you can see the entire manifold put together with 3/4" PEX cut to 3/4" in length, the two end Tee's are only shortened on one side so as to leave the longer end when connecting the in and outputs, also collectors can be connected in parallel. (I have 2 of those patio door windows, and putting 2 solar heat collectors in parallel could surly double the heat output).