OK, I always come up with crazy ideas, and I usually post them first on www.poosnack.com
under the technical forum. This is a place where all of my friends and I go over my stupid ideas, and discuss stuff. But I wrote out a neat idea, and I'm gonna copy it here and let me know what you guys think!
First you need this: http://scitoys.com/scitoys/scitoys/aero/vacuum/
You have a bunch of half inch thick iron plates, make sure you shine one side of each of them to an EXTREMELY reflective level, this will help reflect infrared radiation. Weld all these together to form a box, drill appropriate holes for the accessories which will come later. Fill box partially with water.
Next, hook up vacuum pump backwards, or actually use a professional vacuum pump, and pressurize the s#*$ out of the interior. Make sure for your drilled holes that use a lot of strong one-way air valves (commercially available for cheap) to keep all the air and goodies inside. Do not invert because you don't want water coming through the accessory holes you drilled in the top, cause water will probably go through the one-way AIR valves.
Surround iron box with a glass enclosure, filling the air gap with somewhat pressurized CO2, CO2 absordbs infrared radiation (heat) very well. Good ol greenhouse gas. This is a backup IR grabber for what your reflective interior of the iron box does not catch. Make sure in this outer glass sleeve, you cut a small circular area where there will be no CO2, because this is where you will input your own IR radiation to heat up the box. The outside of the iron box is black, therefore will absord IR very well, and not reflect it.
Surround this outer glass shell (use thick glass for durability sake), with ANOTHER glass shell, this time the air gap is a vacuum. Congratulations you have a big thermos, with a small feed hole for more heat. The circular hole where your CO2 shell doesn't cover, make sure it matches the hole on your thermos glass layer. Make 2 caps that fit each layer, fit snugly, that match the layer they're on. One cap for CO2, (think hollow glass hockey puck filled with CO2), and one cap for the vacuum layer. Of course each glass housing will be entirely enclosed, and the "cap" only fits in the area where the housing has missed.
One of your accessory holes is for pressurizing the chamber, make sure you use high-temp fittings for this. The second accessory hole is for your high-temp output valve, once opened it will do one of two things depending on design. Depressurize the iron box, the water will suddenly explode into steam, and you'll have a big hot steamy mess. heh. Or #2, The valve allows external access that (still maintaining pressure), drops a long sealed copper pipe into the chamber, which is filled with salt water. It will act as a heat pipe and conduct (not convection) heat through to wherever you want. Adjust heat pipe depending on output desired.
How to add heat? With caps off, you have either 1) a dish like mirror that focuses intense sunlight onto the box, or 2) mount a very large magnifying glass to focus heat on the box, so it aims at the uncapped area cause CO2 will also absorb input heat. When sun goes away, replace caps on the enclosure. Being a thermos, you will neglible thermal loss overnight. Repeat process during day. If no magnification or focusing equipment is used, standard arizona sunlight will suffice, but it will take longer.
Water under high pressure will not boil at the usual temp, it will boil a lot higher. You DON'T want it to boil, there is an explosion hazard in a sealed container with steadily increasing pressure. The box is made of half inch thick iron plate for a reason, to contain extremely high pressure. Optional fitting is for a pressure gauge so you know how pressurized it is. Water is contained in the box as opposed to air, because it is a lot better heat storage device as opposed to just air. Some air if left inside to promote convection as soon as you insert the heat pipe. Whatever you do, never ever suddenly depressurize the chamber unless you want to die.