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Old 01-13-11, 04:15 PM   #1
strider3700
Master EcoRenovator
 
Join Date: Dec 2008
Location: Vancouver Island BC
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Default Solar water preheater project based on builditsolar $1000 system

I've been planning and collecting materials for quite awhile now for a solar hotwater preheat system based on the BuildItSolar: Solar energy projects for Do It Yourselfers to save money and reduce pollution $1k systems.

In the past couple of weeks I got my data collection going at the house and have been working out how much my hotwater costs. The thread on that is here. http://ecorenovator.org/forum/applia...g-project.html over the last 15 days I've averaged 9.2 kwh per day just to heat water. Given my location I have a reasonable chance at achieving 70% solar heating. So with my current cost per kwh I can save roughly $198 per year with this system. possibly more because this savings should always keep me in the lower pricing tier and if I achieve 10% savings I get $75 from the electric company as part of a savings challenge... Estimating that the system should run about 25 years with any luck that works out to $11730 in savings assuming 6% price increases in electric and no change in usage. My kids growing up should account for considerably more even if the electric company doesn't get the 10% yearly increases they've asked for.

So with the math working out like that I finally decided to get going on the build and did up drawings with a buddy. Here is what we drew. My address is behind the grey blob....


I took that as well as a yard survey for my house which had a very rough drawing of the placement of the system in the yard to the city and asked for a permit. The basics of the drawing was the tank goes in my backyard, a line runs from the tank to a rear corner where the collectors are. I gave distances from the house and property lines since this will be a permanent structure. for the drawing it was a thin rectangle for the collectors a singe line for the pipes and a small box for the tank. Labels read collectors, inground supply/return lines, tank.

The city said they've never done one of these before but took the application to give to the plumbing inspector who wasn't in. I had to fill out a cover sheet stating the address it was going at, who would build it (me), who owned the property(me) who was applying for it (me)

Yesterday I got a phone call where they had a question. The wanted to know how high the structure for the collectors would be and what it was. I said it's just a wooden rack on the ground and it would be under 8' tall exact hight depended on the final angle of the collectors. They said that's fine but the plumber has questions still and I should call him tomorrow(today now).

Today I've tried twice to get a hold of him but it still hasn't happened.... He does go into the field to do inspections so I'm not shocked that he's not at his desk. So that's where that aspect stands.

So far materials wise I've collected the following

a dual pane sliding glass door with 2 34"x76" doors for free - I intend to split the panes and make 4 single pane collectors.
3x 12' 1/2" copper - $43.58
3x 12' 1/2" copper, 7x 3/4-3/4-1/2" copper T's - $65.45
9x 6' 1/2" copper $70.46
4x 8'x4' 2" polyiso for collectors $89.60
8x 8'x4' 3" polyiso for tank $268.80
40ish feet of 3" pvc pipe for trench $31.36
1 4x3x2.5 fiberglass hatchery fish fry tank. Roughly 150 gallon capacity - free
misc aluminum flashing, maybe 1'x15' worth - left over from other projects

bringing me to a total of $569.25 so far.

Off the top of my head still needed are the pump, a 500' roll of =3/4" pex, about 130' of 3/4" pipe insulation, some lumber for the collector frames, lumber for the collector rack, 3 shut offs, the tempering valve, the backflow preventor, a couple of 3/4" copper pipes. 3 more 1/2" copper pipes More T's and some more aluminum flashing. I'll be using my data logger as the differential controller. I just need to add a relay in place to control the 12V pump.

I buy when things are on sale or free... My hope is to get a final installed cost of under $1200 giving me a 5 year payback.

Right now I'm holding off on buying anything else until I get official permission to do it. After that comes in I'll start making collectors in my "free" time and I'll order the obviously necessary stuff like the pump and roll of pex.

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