shoot, i added a period on at the end of the link! this one should work - http://www.freepatentsonline.com/4613444.pdf
for some reason, it's hard to find high purity calcium chloride here in canada, which is making things difficult/expensive for me. it's funny since we usually have more snow up here than in the states... i've gotten my hands on a bag of Dowflake Xtra and am trying out example #10 right now, since the concentration of salts are fairly close to the mixture found in Dowflake Xtra. i ordered my strontium from United Nuclear http://unitednuclear.com/index.php?main_page=product_info&cPath=16_17_69&products_id=808
, though it looks like they are currently out of stock. comparatively, it's expensive to calcium chloride, but it goes a long way since it comprises roughly 1% or the total final weight of the pcm. as far as my method, i'm basically just following what is written in the examples. I haven't taken specific temperature measurements other than picking it up in my hand and saying, "yup, this one is warmer" but the pcm definitely holds the temp longer than plains water. I'm using corn starch right now to thicken the mixture and suspend the crystals, but I've read that is not a good way to go...at this point I'm just experimenting. I've also tried using Bentonite, since it is similar to Fuller's Clay, which was used by Telkes. Bentonite is basically the clay you would find in clumping cat litter, so kitty litter is what I used(non scented). Needless to say, it didn't work too well. On the bright side, I also found a video online explaining that Bentonite is also the type of clay they use in fancy salons for facials. My fiancee was not impressed when she came home to find me with dried cat litter smeared on my face...(if you're wondering, it works, feels great, and takes years off your appearance!
I believe most PCMs use Sodium Polyacrylate as a thickening agent. I really should take temperature readings and plot them to see how effective they are, and if they are degrading with cycling, but I don't have any thermometers around
As an aside, my extra arduino r3 isn't working - have you ever run into this as an error when uploading -
avrdude: stk500_getsync(): not in sync: resp=0x00
avrdude: stk500_disable(): protocol error, expect=0x14, resp=0x51
i've gone over the forums people have suggested fixes, but noting seems to work for me. don't look it up, just wondering if it's ever happened to you. i think i may have fried the ATMega328 somehow....
the heliostat, on the upside, is preforming fabulously!