I have discussed this project with author Dag Atle Lysne, and he had several suggestions to alternative materials and programming tools. By using Lego bricks, there are some problems with the door solution. The door tend to become either to heavy for the motor or not solid enough to tolerate the frequent opening and closing to regulate the heat. Lysne suggested using other materials like wood, metal, plexiglas or plastics to lower the weight, and combine it with some Lego components.
He also told me he had tried using other programming tools, to increase the difficulty level and gain experience with other tools than Robolab. I do not know which tools he referred to, but I will try to figure it out if anyone are interested.
[Update: A friend of mine, Rob, has written a post about our science center, and suggests some other tools for programming. Thanks!]