How it works:
An antifreeze solution is pumped through two solar collector panels on the roof. This fluid is then pumped through a coil inside of a large water storage tank located next to our existing propane hot water tank. If the solar panel temperature is 10 degrees higher than the storage tank bottom's water temperature, a circulating pump turns on. Heat from the solar heated solution is then transferred by conduction and convection within the storage tank. When we turn a hot water faucet on for showers, dish washing or laundry; preheated water from the top of the storage tank enters our existing hot water tank, reducing the amount of propane needed to raise well water to 120 degrees Fahrenheit.
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| Two solar hot water panels. |
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| Air temperature - 38 Faherenheit in the shade. |
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| The inhouse temperature probe (left) and various pressure gages for easy system monitoring. |
The above video clip was taken at 2:30 PM local time.
- The 1st number is the temperature of the antifreeze solution in the panels on the roof. (121 F)
- The 2nd number is the temperature at the bottom of the water storage tank. (102 F)
- The 3rd number is the water temperature at the top of the water storage tank, which feeds our existing gas heated hot water tank. ( 89 F)
As you can see the water entering our hot water tank is preheated by the sun. Before the solar water heating system was installed, 56 - 57 degree Fahrenheit well water would enter our hot water tank and then have to be heated with propane to 120 degrees Fahrenheit.
The following video clip was taken later (5:35 PM) as the sun is now lower in the western sky. As you can see, the solar panel temperature is down (47 F), but the temperature at the top of the storage tank is 97.8 degrees Fahrenheit. Water entering the hot water tank will only have to be heated 23 degrees vs 57 degree water coming directly from the well under the old system.
We will be watching our propane bills, so check back in a few months.
Sounds like a brilliant system!
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