Another Idea I’d propose here: Instead of making just coffee, why not allow, say, Tea or Hot Chocolate as well?
A standard coffee maker makes coffee by heating water to boiling and sending it through a filter with coffee grounds in such a way that it eventually comes out as coffee. It might be simpler, therefore, to boil and store hot water, carry tea bags and/or hot chocolate packets as well, and make the coffee by storing the hot water and only making the coffee by percolating it through grounds. It might make the design more compact and versatile, since other hot drinks generally boil down (no pun intended) to hot water.
Thus, the CoffeeBot could provide a cup of hot water and a tea bag/hot chocolate packet (maybe even sugar and milk?) for those that can’t have coffee, and could percolate the same hot water for those through the grounds for those that want coffee.
Just using a water tank separately would improve the heater’s efficiency, since the tap water won’t leave as much residue on the inside of the tank as the coffee itself (Which would cause fouling on the heating element, and reduce its effective heat transfer efficiency over time); and cleaning since the only real cleaning one would theoretically have to do on a daily-weekly basis is cleaning of the percolator itself.