http://ecomodder.com/forum/showthrea...age-26724.html
His plan was water based, but the idea is the same, the problem is you can store so little heat that it isn't worth all the work.
How many lbs of wax do you want to carry? From 80 dF to 200 dF including the latent heat it will hold about 126 btu's/lb. 200 lbs wax = 25,200 btus.
Wax is less dense than water, so 200 lbs of water would take less space, be easier to tie into the radiator, and give 120 btu's per lb. for a total of 24,000 btus for 200lbs of weight.