Construction of a cool-growing box - ideas?

[calvin_orchidL]

I'm thinking of constructing a cool-humid grow box for my neofinetia and my coelogyne nitida. I would like the temperatures to drop to about 4 degrees C (40F) at night, but be a good 10 degrees C (50F) in the day. I want humidity to be around 75% which is impossible unless inside a closed space. The setup I was thinking of was to use a swamp cooler which has been alluded to several times, enclosed inside some sort of box with the plants inside, as well as a fan and some lights.

I was thinking that if I run the cooler for a few hours in the evening, then the night temperature will be sufficiently low, and the day temperature will be higher when the CFLs are on and there is sunlight. While the neo enjoys a bit of water during the winter, the coelogyne really seems to rely on the moisture from dew/fog during the winter months. You may be thinking why I'm going through all this trouble to do this (since I could theoretically just spray the plant every day)- well, the situation is that this plant grows at home because I can't bring it to my downtown residence where I have dry heaters blasting away. At least I have a cold window at home where I can put the plant in front of. However, since I spend the week at my residence, I can't be home to spray the plant every day. So I decided to bring the whole shabang downtown with me - build a nice cool box for these two so I can monitor them.

I have some questions though, before I embark on this project. If anyone has experience building something like this, I would really appreciate any input.

1) I don't think people use swamp coolers ever this far north. I'm looking for mini ones - I recall someone saying that these exist. Are you talking about something like this?

2) Assuming I can get a mini one, I need some sort of box to hold in the low temperature and moisture. This is where it gets a little tricky - At first I was thinking of getting a glass aquarium and just inverting it to make my box. However, I am having trouble finding one that is large enough (for a budget). I need something that is at least 2ftx2ftx2ft in dimensions to accomodate my plants and the cooler. Plus, I wouldn't know how to mount my lights inside the thing. I was therefore thinking of building a frame cheaply out of some PVC piping from home depot, and wrapping some sort of insulator plastic around it to make the box. That way, I could hang my light from the PVC frame inside the box. Does this sound feasible or completely ridiculous? Any materials come to mind? What about that plastic stuff people use to make green houses with?

3)What will happen to my CFLs if they are mounted inside with 75% humidity? Will water get into the ballast and short the light? I don't want to have any electrical accidents.

4) I feel like I need some sort of exhaust fan. Will this provide sufficient air movement or should I also install internal fans?

I'm looking at all of you who grow dracs and have fantastic setups to give me a hand here. Any ideas would be appreciated. I know this may seem like a lot of work for a couple of plants...I mean, I suppose I could nag my mom into spraying the coelogyne for me every day...but I'm thinking it could be a fun project to try out! (Plus, I really do like these two plants and I want them under my watchful eye).