Solar Water Heating on a shoestring
Wednesday, March 30, 2011 2:50:51 AM
This assumes you are not a total Muppet ;-)
The design of this system based on a simple pumped closed circuit system, you could, if your layout allows you could forgo the pump and use a thermo-syphon system but more of that later.
The system I have built consists of cheap and in the case of the pump (an old washing machine pump), second hand.
List of parts;
Low pressure Hot Water cylinder, triple inlet type. (not costing this as new they are about $950 but you can get one for as little as $100 or you may even have one in your existing heating system.)
2x20 Mtr rolls of 13mm garden irrigation hose, availiable from the Warehouse or Mitre 10, about $17 each.
20x90 degree elbows (bends to the uninitiated) @ $4 for a pack of 4
40 odd clips (you could use tie wire if you want to be real cheap ;-)
1 3.6 mtr sheet of clear polycarbonate roofing @25 there are different makes and types but don't be too fussy, cheap is good for this project.
Thermostat Switch Jaycar JaycarPart No. st-3831
Cut tube into 3.2 meter lengths and cut 9 bits at 60-65mm
Assemble as shown.
You now have the basic collector.
All you have to do now is mount it on your roof. If you have a corrugated Iron roof you will find that this sit neatly in the runnels of the iron.
Now is the best time to fit the thermostat.
I have found that the best way to fit this thermostat is to prewire it and, using a light or even silver tape and fit it halfway down the last tube before the outlet tube.
The next step is to cover the collector with the Poly carbonate and fix it to the roof. I found that by removing your existing roof fixings and replacing them with screw type roof fixings all will go smoothly.
Next, Connecting it all up.
Well, it's all connected and installed. An old washing machine pump drives the system. Water is pumped around the system through a 185 ltr triple inlet water cylinder and through the collector. The pump is controlled by the thermostat that has a fixed switch over @ 55c. In bright sunlight this cycles at around 12 minutes and runs for about 1.5 mins. As yet we haven't achieved hot water from the cylinder but that is down to the time of year, we have got warm water though but not hot enough for a shower yet. In the meantime we will rely on a califont cos a cold shower sucks eh?.
Meanwhile, here's Jason...