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Hot Water Solar Panels |
open loop drainback solar system with thermosyphon panels
I am by no means a tree hugger, but I do feel a responsibility to the environment and of course my wallet. There's just something good about saving money and the environment at the same time that brings a smile to my face. It amazes me that more people don't use solar. I think that is because people feel that it is expensive and complicated, as I did when I first started making plans. I will explain my low tech system in the hopes that someone can benifit from this information. The system described below heats this house exclusivley in the spring and the fall months and suppliments the heat in the winter.
Below is an example of an open loop hot water solar panel heating system. When I started looking into the possibilty of using solar a few years back things were either complicated and expensive or back woodsy and homemade. The panels that are used in this system copper pipe under black tin inside of an insulated case. The best and most cost effective way to heat your water up is the thermosyphon. All you need to do is have your storage above your solar panels. Depending on the amont of sun will depend on the amount of water movement. For roof mounted panels thermosyphon is not an option in a colder climate and requires a circulator pump. The storage tank / electric water heater is an expensive item and is not used in this system. This house was built in 1910 and has an oil fired furnace with cast iron radiators. I figured that the existing radiator system in the house held 100+ gallons of water. By tapping into that system I was able to use the water and all of the radiators as my storage tank. The principal behind it is when the sun is out and there is a higher temperature in the panels then there is in the house the circulator pump is turned on. That in turn circulates the hot water from the panels into the existing radiator system. In the spring and fall the house (which along with the radiators is acting like a storage tank) can become warmer then wanted and one of two things at that point can happen (1) turn off the differential controller / circulator pump or (2) open some windows. The oil furnace can still be used if needed, but I haven't used it for two years now. These solar panels along with pellet stove is all that this old house needs. |
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thermosyphon panels |
pipe up to the tank |
thermosyphon panels |
Pictured
above are the panels below the drain back tank in the attic. These panels
work on the thermosypon principal and have water in them all the time.
3/4 inch cpvc pipe from the low side of the drainback tank is hooked
to the low side of the panels. And the high side drainback tank is hooked
to the high side of the panels. When the panels heat up the cold water
sinks out of the tank and the hot water rises out of the panels. These
panels are on a protected side of the house and tend to heat up more
that the less protected panels on the roof. |
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drainback panels |
roof view |
3rd view |
Pictured
above are the roof mounted panels. This is where the differential controler
sensor is installed. When the temp is higher in these panels by 7 degrees
then what it is in the house it turns on a circulator pump. The pump
feeds these panels from the radiator system in the house. The panels
are empty when the circulator is not running. Directly underneath them
is drainback tank in the attic. By keeping the system as an open loop
system I did not have to worry about things like pressure and extra
costs involved with things like that. |
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top right temp sensor |
thermosyphon temp |
outside temperature |
The
day these pictures were taken was on 11-19-08 in Lancaster PA. The day
was sunny and the pump ran from approximately 8am to 3pm for 7 hours.
The thermosyphon temperature sensor at 12:20 showed just over 100 degrees
while the oustide temperature was a hair over 30 degrees. |
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solar panel temperature sensor |
roof panel temperature |
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Inside
the panels on the roof the temp sensor read 83.4 degrees as shown on
the differential controller. |
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| Ok here is the storage tank. You can see that not a lot of money was spent on this item. I think it was actually a $5 purchase. If you went with hot water storage tank with the heat exchanger this would be more like a $1000 purchase. And for me that wouldn't have worked here anyhow due to the space constraints. This is where the thermosyphons below heat into and where the roof panels drain back into when the circulator is not running. Stupidly I have not insulated this tank yet and that is surely loosing some of the heat. The tank sits in a hot water heater pan so that if there are any leaks that it will drain into the pan and then outside the house. That same style pan is what I use for a lid on the tank. |
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The system is lightly anti-freezed because of the panels on the deck that have water in constantly. If it wasn't for those panels this system could run on pure water. Also added to the water in the system is rust raider which helps keep things from rusting. This is because the system is open loop and allows for oxygen in the water. The radiators in the house do not heat up like when the oil furnace used to fire them, but they do have a warm feel to them depending on the day. And between all of the water that is in the radiators and the water that is in the piping in the basement of the house feeding them, it fills the house with a solid radiant heat. This is my low tech solution to what in research seemed like a very high tech way to heat. The priciples are simple, the sun heats things up and you have find a way to utilize it. Hope you enjoyed my solar project. Scot Sherbine Next on the docket is solar hot air panels for the garage... even lower tech and with no moving parts. |
webmaster Scot Sherbine
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Tel: 717.478.8283 Lancaster, PA