Hey folks -
Being that there are so many people here with a) way more experience than I have in building grow chambers and b) a much better understanding of thermodynamics than me, I thought I would reach out to see anyone had any bright ideas for me.
Basically, I recently re-did my grow rack (see my "Grow Rack Re-Pimping" thread in this forum for details). After messing around with the ductwork, the humidifier placement, and adding heatsinks and cooling fans to the lights, I've managed to get temperatures relatively stable between 72 and 84 degrees. In the winter, due to lower ambient temperatures in the room, the bottom end of the temperature range will likely be in the high 60s with the top end still staying around 84 max. With my humidifier I can maintain humidity of 60% minimum and 95-100% maximum. I just need to get myself a hygrotherm or other humidistat to make sure that minimum RH is maintained. With me not around to turn the humidifier on, minimum humidity drops down to about 49% at the lowest.
NOW - here's the deal. My conditions are great (or at least close enough for government work) for lowland Neps. I would love to be able to grow some highlanders but I would need to do some work to get an adequate temperature drop (and to keep the maximum temperature closer to the high 70s rather than low 80s).
I see people here with crazy rigs like air conditioners dismantled and put inside the grow chamber, or cool air piped in from an outboard AC unit. Unfortunately my lease on my apartment limits me to one 6,000BTU unit due to old, crappy wiring... and that quota is already filled with a unit in my bedroom (crucial during NYC's miserable summers).
I also see folks (swords, I'm thinking of you) pipe cool air in from a nearby window. That would be great if a window were accessible! Unfortunately, as I've explained in other threads, my grow rack is set up in my girlfriend's study. I'm operating on borrowed space; her desk is in the window and I can't in good conscience run a big fat duct across her workspace to get at that precious cool air!
I open the floor to you guys.... What do you think I could do to lower the bottom end of my temperature range? Some sort of evaporative cooling mechanism? A heat exchanger? Some magic black box that takes in pixie dust and puts out pure chilled air? I'd like to hear of some successes (or failures) that folks here may have had in their quest to create the perfect grow rack.
Thanks, and I look forward to hearing your insights!