[b said:
Quote[/b] (swords @ Feb. 08 2006,10:59)]Remember that cold air falls (even when fanned) and warm air rises so you should find a way to mount the ac to blow in the top of the chamber so the air will circulate downward (naturally) and keep the plants on top shelves cold enough and not too cold on the bottom.
Also, realise that the A/C creates very dry air so you will want the A/C cooled air to be presaturated with humidity before it reaches the plants to avoid a dessicating sort of draft. I had setup sort of the way you describe at first and all my hamata lids snapped shut overnight. Once I made it so the air was presaturated they opneed right back up over the next night.
I really don't think the small in dish thing will make a thick/effective enough fog, those are really more for looks.
There's no way to put the A/C in the top of the chamber. I've thought about the thermodynamics at play but the only way would be to make a new cover for the rack with holes at the top, and beyond that I'd have to have the A/C hanging outside the rack on a separate support in order to have a humidifier in front of it. I know that A/C air is dry and the transition is too sharp for most Neps. The A/C is going to go underneath the entire rack, blowing into an inclined surface to force the air up.
The rack is divided into three shelves, and for now I'm only lighting the top one, which should fit all of my CPs that need climate-controlled conditions - Cephalotus, Heliamphora, and Nepenthes. A few humidity-loving houseplants will occupy the second shelf for the time being. The lowest level will have the humidifier, heater, and fans, and the whole rack will sit in a drip tray. I want to run some PVC pipes from the top to the bottom with low-speed CPU fans to pull warm, humid air down from the airspace near the lights, forcing the cool air to the top gradually. RH goes up as temperature goes down, so the warm air can be used to pretreat the A/C air for humidity. In this way, instead of blasting plants near the A/C with cold air, the plants on the bottom will get relatively warm, humid air while the fans and A/C are on.
The in-dish humidifier I was referring to is not one of those decorative ones - it's the same idea, but a much larger unit used for special effects. There are units that displace up to three litres of water an hour. They come with buoys to float them at the proper level in a volume of water, so they can be placed in rather large resovoirs. It should suffice. As I understand it, ultrasonic humidifiers wear the fastest when they're run without water; if you were keeping yours in a shallow dish, perhaps that's why it wore out so quickly. I like the idea of simulating rain seasons - I'll have to try that.
Thanks for the tips.
~Joe