Temperature Control in Orchid Boxes

What temperature range do you want? Lighting should raise the temperatures somewhat when on, and provide some difference, especially if the light sources are inside the box. Separating the power sources from the lamps will allow you to moderate temperature gains.

If you are on a quest for cool, you could use an aquarium chiller timed to run overnight, pumping chilled water through fin tubes in the box.

Can Peltier devices move enough heat to be worthwhile? They aren't that efficient...

 

If you are lucky enough that natural cooling is sufficient, placing a heat mat on the bottom (connected to a timer) is sufficient to heat it up.

For Peltier coolers to work well in a tank environment, they need to be tightly bonded to a pretty good sized heat sink, and have a fan actively blowing on them, so that there is a large volume of slightly cooled air, rather than a small volume of very cooled air.

 

So, CPU cooler with fan mounted on both sides. Probably would help to have it up high in the tank...

 

I haven't but a PC in a while, but aren't CPU coolers just heat sinks with fans to disperse the heat?

I think the thru-wall idea is a very good one.

 

Most CPU coolers are just heat sinks with fans, but you can also get systems that have heat sinks with water chambers, plumbing, a pump and radiator on the outside. I suppose you can hook 'em up backwards, with the radiator on the inside of the box.

But, the through-wall idea, with CPU heat sink and fan on both sides, is what I would do.

 

The idea is a buoyant, tumbling air flow, not a "breeze", per se.

Yes, you'll want some fresh air exchange.

 

The only issue with the pelt that I would have is they take alot of power. What size pelt would you use. That is a large box you are trying to cool/heat. Basically a fridge. I cant see not having to use a 300-500 watt pelt. You power bill for running 24 hours is going to take a hit. You can use a cpu fan controler to adjust temps just make sure it has temp sensors you can mount you can adjust fan speeds on the heat sink to adjust temps i would water cool it. it will be less noisy. I wouldn't recommend reversing polarity due to the size of the pelt you would need. Unless you plan on it having a melt down. You have to be able to move the heat fast. a pelt never reaches a stop point it just gets hotter and hotter and hotter. Until it melts and trust me my fingers can vouch for that. The heat sink on the cold side would not be good enough to be used as a hot side. It would just get to hot. If it was a small box like a 2.5 gal or 5 gal size a pelt would be awsome. But your box makes thing more complicated. Jmo but I would love for you to try and see what you come up with it is possible you just have some issues to work out. Good luck

 

You could fab up some type of evaporative cooler. All it needs is a fan and a pump so much cheaper to run than a Peltier.

 

Evaporative coolers are ideally arranged so that they take warmer, drier, outside air, and propel cooler, moistened air into the enclosure.

However, I've seen swamp coolers function well inside of a greenhouse in Houston, so at 60% RH, it would probably still have some effect.

 

If you keep the door open, it should dispersed well enough to no be a problem

 

If your room is totally sealed, then yes, you're right. Otherwise, I wouldn't worry about it.