Roger,
The cost is from his own notes, for the type of insulation he wanted he "foamed " his own at a cost of 450.00. The galvanized metal liner he had fabricated to his specs at a metal shop. The plastic liner, type, construction, and the way it was seamed he had fabricated, again to his own specs. Custom work does not come cheap. He must have done it right as it has worked this long, could he have done it cheaper, maybe, would it have lasted?
His name is Bob English you can email him through that web site for further info, and detail. That web page simplified its construction, as with many things the devil is in the details. As someone who loves things cheap, I have come to learn that it can be a false economy, I have come to believe that if it is good enough to do, then it is often good enough to over due.
That weight is very significant, the water, then the other materials are going to be nearing one ton, you better place that over a load bearing wall. He did, the center of mass is over a outside wall.
Just to give you a idea on what custom metal fabrication costs consider this, you are walking into a metal shop with your specs for a one off. I would estimate that just to build that inner galvanized box would require at least two full 4x8 sheets of galvanized steel, considering the weight surounding it, I would not go less than 14 gauge(12 would be better) so 2 sheets at 70 a sheet, so 140.00 in material for just the metal box. Now this is not that complicated of a box, but due to what it must keep out, I would have to suggest folding the edges and soldering the seams for a proper job. To estimate labour it would be reasonable for a shop to assume one day at a shop rate thats appropriate for your area (say 85.oo per hour). So 8X85= 650.00+140 gives you a cost of 790.00 for your custom fabricated box (I think A good sheet metal man could knock that box of in 4hrs). You get the idea, costs climb fast, nothing is as cheap or as easy as it first looks to be.
The type of controler I suggested can be found for sale at amazon.com for 47.00, plug, and play no wiring skills needed. Search under the heading "refridgerator or freezer thermostat"
PS: I just seen where you mentioned saving power in winter from your PV. If you set up a fridge like mine (roughly a 600.00 fridge), then add a 50.00 dollar controler, and can live with a 5.5 or so cuft fridge (bet you can with a little thought), you should be around what i am at .266kwh/day, now if you wish to go even better, keep a couple 8 liter jugs of water frozen outside in the winter. From my tests a couple years back by placing one frozen 8.5 liter jug in my modified fridge, my use dropped to .500 kwh in 72 hrs, in other words by rotating out a 8.5 liter jug of frozen water every 3 days my fridge used just 166 watts a day or if we go by a hour average thats just 6.94 watts per hour. Sure my fridge became maybe 4.5 foot fridge then due to the volume taken by the frozen water, but I still had lots of room. Anyway, you can see why I didnt consider building that monster fridge- to much work, to heavy, took up too much room, and to expensive, for me anyway.
Now the fridge he would have been replacing would have been from the 70s, it may have used 2, maybe 2.5 kwhs a day, and building that fridge was one smart move, made sense in every way, but now?
I cant see how it could be when I am only using a couple hundred watthrs a day. I may only have 5.5 cuft, but his was only a little more at 9cuft.
