March 28, 2010

The wheels and track have just been welded. I found two iron cots (sleeping frames) that were being used for the last 25 years to keep wild dogs and coyotes from entering our chicken pen. These cots were constructed with rivets which I ground out with a hand grinder, and ended up with four rusty angle iron pieces to use for the "U" channels. The wheels came from a scope cart (Not a Tektronix cart!) constructed for the Gov’t under contract about 50 years ago. Very heavy duty. I cut the metal cart right down the middle with a metal cut-off blade in an old Skilsaw, and then welded it back together with a wider wheelbase to fit my tracks. Here’s a photo:

Quite a bit of progress has been made on the oven. Using a thin cut-off disk in a 4 1/2" angle grinder, I cut a ring from a stainless steel mixing bowl and attached it to the enlarged hole in the dishwasher carcass. Then I constructed a frame around the whole works and started mounting steel panels. When the box is complete, I can pack the space between the inner box and the outer box with fiberglass insulation. Here is a photo of the what I have so far:

April 3, 2010

During the last few days, we have been cleaning a space near the barn for the operation of the array. At first, I was going to drag it down a slight incline in the driveway to a level spot in the pasture, but this thing is gaining weight. So, a woodpile and a stack of old lumber was sorted and moved so the Helios can be operated right near the entrance to the barn. An unbelievable amount of work! I did make some progress on the oven. The cart will hold the oven on four posts that mate into four sockets on the bottom of the oven. (So I can remove the oven, and still use the wheeled cart for other applications.) The oven design is much more complicated than I thought. My wife is quite concerned that my oven simply would not work, so we came up with a different plan. The light will enter the oven and strike a heavy steel plate mounted at an angle. The plate will have skirts welded to it to provide thermal mass. Behind the skirted plate with be the oven racks. A large granite block will sit at the bottom of the oven for more thermal mass, and will act to keep the iron plate from moving. There will be a thermocouple and digital pyrometer showing oven temperature. (http://www.sundanceglass.com/pyrome...) We imagine pre-heating the oven, and then inserting the food..and monitoring the temperature with the $39 pyrometer. The oven is still under construction, but the space near the barn is clear, but not exactly level, so work continues...

Potential applications for my Helios:

Baking: (Our first project will be a roasted chicken!)

We typically make 32 Pita Breads at once, using a pair of black cast irons pans and a Anderson Champion TLUD-ND (Top Loaded Up draft-natural draft) gasifier out on the patio. This requires a 500 degree F. temperature for about 90 minutes. It took a while, but we have this "down to a science", and it works every time. However, cooking a chicken or turkey in a pressure cooker over the gasifier makes for good stew, but doesn’t compete with an oven-baked fowl.

Water heating: My existing solar water heater doesn’t get water warm enough in the Winter, but will produce all the hot water we can use during Spring, Summer, and Fall. (During the Winter months, we use a timer/switch on a second hot water heater to only heat the water when needed. Immediately before using the water, we turn the switch off, so the water isn’t heated as it is withdrawn from the tank. The lower heating element has been disconnected, so only the upper element is being used. There is an incredible stratification of water within the tank. Only the water in the top of the tank is hot. The rest is cold.) The water storage tanks are located in our basement, so a 115 Volt TACO 006 pump on a hand operated switch moves the hot water down into the top of the tank, and pumps cool water from the bottom of the tank outside to the solar collectors. Of course, even the Helios won’t work if it rains for a month! When the Helios is completed with 54 mirrors, I intend to hook the two tanks in series, and pump much hotter water into both of them. There should be no shortage of very hot water. (Hopefully)

Kiln drying Mesquite Chunks: Kill the little yellow worms! These worms can destroy a nice hunk of mesquite by boring round holes in every square inch of it. It ruins a nice hunk of hardwood! My spouse is a woodworker, and has a site at http://www.woodworks-by-donna.com/ She doesn’t want any wormy wood anywhere near her precious wood storage bin!

According to Wikipedia, most softwood lumber kilns operate below 240 °F (116 °C) temperature. Hardwood lumber kiln drying schedules typically keep the dry bulb temperature below 180 °F (82 °C). Difficult-to-dry species might not exceed 140 degrees F. This might be a good use for the oven when it is not used under full power for baking. I’m thinking a chimney might provide natural draft to keep the air moving. Most of the wood we use for wood working projects is small chunks, for pens, pins, or band saw boxes.