New growing space - help needed!

[NKOrchid]

Hello everyone,

I'm building my own growing space which consist of one aluminum bookshelf (3 shelves). I've also bought two computer fans. My thought is to wrap the shelves in see through plastic bags (yes, this is quite low budget) and install the fans, (perhaps a humidifier or two) and some lights in the space.
I've looked at some lights and I've done my research, but I'm still so confused. As far as I've understood 1 lumen = 1 lux per m2. The lights I'm thinking of buying (setup per shelf) is one 150W 2700K and one 250W 6500K - one shelf is about 0,36 m2. The 150W and 200W combined has an output of approximately 25.000 lumens which is 25.000 lux per m2, but since the space isn't 1 m2, the lux is way higher. Even if I round up to 0,5 m2 space the lux will be doubled to 50.000, which is about 4600 foot candles. That's a lot of light and enough for post orchids (and too much for some), as far as I know.
Are my calculations correct? Or am I missing something?
Also, I'm a little afraid of the heat these bulbs will put out. My space isn't big and the shelves are grid, so all the plants on the different shelves share the same air and temperature so the space in total will maybe have 2 - 3 of each bulb.

Does anyone have any experience with having a lot of watts in a very small space? And does it sound like this would be enough lumens or is it too much? I'm thinking of using tin foil as reflector.
The plants I have are 1 phal, 2 cymbidiums, 3 oncidiums, 2 dendrobiums and one miltoniopsis.

Looking forward to your advice and sorry for the messy post!