Solar Heating System SHS-1

ImageAfter extensive testing of the SHP1 (solar heating panel 1) I found the results extremely encourging, in zero degree weather I was able to reach an output of 73 degrees C, details for SHP-1 can be found here.

The new (No aluminium can) design was not construced for the following reasons:

The only problem I found was that the heat was only produced in full sunlight so there is no heating at night or whenever there was no sunlight this also applied to the new design that eliminated the use of aluminium cans.

The evenings in the lab became rather chilly when the sun went down or it was cloudy and I won't even mention the mornings lol. An idea came to me last summer when I noticed that a large pot of water that was used to cook corn on the cob in was still very warm even after the stove had been turned off for over 4 hours.

Now if I were to heat up a large storage tank of water I could simply extract the stored heat for a longer period of time, even when there was no sun !

After I googled a few keywords like "heat storage" I found out that using water is 1 of the best ways to store heat and a few very interesting videos found on about modular heat storage.

The Solar Collector

The Flat Design:
Using copper tubes is no longer economical and must be replaced with PEX, which is made of some kind of plastic and most probably does not conduct heat as well as copper. In order to transfer as much heat as possible to the PEX, for testing purposes aluminium fins were a fixed to both copper and PEX tubes then painted black.

Tests were conducted during the afternoon with many cloudy periods but results were rather surprising, the PEX tube heated the water faster but also lost heat quickly.
Starting temperature of the water was 22.6 deg. C. and quickly rose to a maximum of 50.9 deg. C.
Both tubes had an almost identical max temp readings, PEX = 50.9, COPPER = 50.6
So this PEX collector tube design seems to equal or better conventional copper tubes with the same amount of surface area.

Solar heating collector The top and bottom headers are made with 3/4 inch PEX tubing to allow maximum water flow and the rest is 1/2 inch.

I found using 6 inch strips of aluminum sheet was much eaiser to form and work with also instead of using epoxy I switched to fiberglass resin and hardner to affix the PEX to the aluminum.

The black paint I used is high temperature flat black metal paint.

Evacuated Tube Design
DIY Solar Evacuated Tube Collector Another collector design uses evacuated tubes to collect heat, I've seen water boil in one of these tubes. The design is very simple, a black glass tube is incased in another transparent glass tube and the air between the two is removed.

My prototype design will use 4ft. neon tubes as my outer glass tube and a copper pipe painted black for my inner tube, the ends will be sealed with fiberglass resin.
Test showed improved temperature gain of almost 9 degrees, although the surface area was much larger then the orignal test tubes the results after sitting in the sun for a few hours are still proof that this design is more efficent.
DIY Solar Evacuated Tube Collector

Heat Storage Designs

Modular Heat Storage:
This video was by far the best information on heat storage and stratification I found.

Here are 2 CAD's of the setup, the first using a pump to circulate the water and second using convection: