Under the cooling secion, will the bottom few inches of water lie inside or outside the chamber? If inside and exposed to vacuum, the water will likely evaporate and contaminate the vessel. I wasn't sure if the water was contained and inside the vessel.
Also, I'm concerned about the heated bed being aluminum. It should be heated to be very close to melting. I planned on porcelain (which, I'm learning, is not very exotic or expensive) as the heated bed. A thin tile should be thermally responsive, and provide the tack necessary for aluminum to stick.
The page is looking good.