Any other forms of daily puja without lighting a lamp?

I know how integral fire is in our puja, especially the daily upasana. My problem is that I'm moving abroad and the student hostel I'm living in has a very sensitive fire detector in each room. Lighting up a little diya, even a tea candlelamp or agarbattis wouldn't be possible. I can offer flowers and prasad but i dont know how to complete my puja without a lamp. Do you know of any alternatives mentioned in our books for fire/deepjyoti? Also, is there any way mentioned to cleanse the house before entering it? As it's not possible to do a griha pravesh ritual in the room because of it's strict rules.