What do you need 240,000 lumens for? You obviously need to overpower the ambient lights but your average 5,000 to 10,000
lumen can do that EASILY. We use a 4,500 Lumen LCD Projector at my college and it even overpowers the wash from the stage lights. I especially recommend a LCD Projector in a permanent install because it will be easier to change the images if you want to and easier to service. Not only that but They make LCD Projectors that connect to a network and run slide shows automatically or you could run video if you wanted to at a later date. Check out
Christie - Providing Digital and Film Projectors for Any Application they make some really powerful projectors (up to 30k lumens.)