Cool growers in a warm climate?? - Orchid Board

Greenman · #1 03-05-2007, 07:06 PM

I was wondering if a terrarium could be temeperature controlled to grow cool growing mini (Pleurothallis, Masd. Draculas, etc.) in a warm climate like what we have here in Miami. Also could an automatic mist system be placed in such a unit? Thanks in advance for any info you can give.

blueovalgal · #2 03-05-2007, 10:26 PM

I think it's possible. That's what I'm trying to do... When I was looking at some posts a few days ago, I noticed that my set up is very similar to the set up, I think, Wendy had. That is, my boyfriend hooked up a duct from the window box fan into the top of my terrarium to blow in the cool air we've been experiencing here. I have the terrarium sitting on my desk, and my desk is located in the bay window. When the days and nights start to get warmer, I'm going to have my boyfriend move the AC unit to the other bay window... then take the duct from the window box fan and attach it to the AC unit.

I don't have any kind of misting system in there. I have most of the masdies in clay pots with spag moss. Some masdies I bought last week arrived in net pots, and I decided to leave them in that. I spray the moss every morning before I leave for school and then during the day as need be when I get home. My boyfriend made me a very ugly but interesting fountain in the terrarium. I can't tell whether it's making a dent in the terrarium, but I do like looking at it.

I'll be interested to hear how everyone else is doing this. I know I can always improve my set up... Hope this helps a little, Barbara

Ross · #3 03-06-2007, 09:22 AM

Quote:

Originally Posted by Greenman

I was wondering if a terrarium could be temeperature controlled to grow cool growing mini (Pleurothallis, Masd. Draculas, etc.) in a warm climate like what we have here in Miami. Also could an automatic mist system be placed in such a unit? Thanks in advance for any info you can give.

There's another thread regarding cooling from a person over in Denmark, I believe. As for misting, sure you can use misters, most of us either use an automatic system of hand misting.

Magnus A · #4 03-06-2007, 11:30 AM

Hi
If you mean me, I am from Sweden!

To the question, YES if it is possible in Sweden Why not in Florida?
Below in the picture you see a terrarium cooled with a slaughtered refridgerator (cooling plate seen on back wall) and a freeser seen below were cooled air is circulated through the grey pipe with a fan. Daytemperature is set to 21 degree Celsius and night temperature to 11.

In this post you can see a butiful cabinet cooled by circulating air from a freeser/refridgerator possitioned in the cubord under the cabinet. Here I also link to a company producing cooling devises driven by peltier elements that seem to be possible to use.

/Magnus

Ross · #5 03-06-2007, 01:30 PM

Pardon me Magnus. Yes I meant your post and didn't bother to look up your country of residence. I am sorry for that. At least I didn't say Norway

Next time I'll be more careful.

Greenman · #6 03-06-2007, 11:07 PM

Thanks for the advice, I'll try to see if I can start putting together such a set up.

Magnus A · #7 03-07-2007, 03:30 AM

One more advice

Cool surface and moisture will give you a nice condensate (water) on the cool surface. This water has to go somewere, (usually gravity pull it down), and think twice were it will end up! Othervice you can get som big problem with water dammaging you construction OR soak your plants!
And misting system can always be installed but you need good airmovement!
/Magnus

Pippin · #8 03-07-2007, 10:14 PM

Magnus,
May I ask you why did you chose to use a fridge-freezer versus a small AC unit? Do you think (or had a bad experience) a small AC unit will dry to much the air?
I'd like to set up something like that, but I have no experience with growing plants in very small enclosed spaces.

Magnus A · #9 03-08-2007, 04:43 AM

Pippin, I must first say that I only planing to build a cooled orchidarium. The pictures I show and the solutions that is used is others. In Sweden I would say that the market for small AC unit is non existent compared with the US market. Therefore I have not seen any AC unit small enough so I have not included them in my personal survey of options.
About drying out the moisture you will always have problem with cold surfaces and humidity. Colder surface more condensate due to the dew point shifts and the air close to the cold surface will hold much less water.

Magnus A · #10 03-08-2007, 05:34 AM

Some thought about humidity:
Air holds more water vapor at a higer temperature (T) than at lower at the same relative humidity (RH)! This mean that if we have 100 % RH at a certain T and we lower the T we will have water condensating out from the air.

How to cool an orchidarium?
We have many options but in the end we need a cold surface that absorbs the heat energy. We can simplify the problem by only looking at the cold surface.

Next question, how much heat do we need to take away? We need to simplify again. Lets say that the surface area of the cooling element is fixed! Lets assume that we have only two options one good constructed, well isolated cabinet and one badly conctructed cabinet were we need to take care of ALOT of heat (from light and the surrondings).
So in the last case we need to transport away alot of energy! Therefore we need to have a very cold cooling element (heat transfer rate is depending on the temperature difference). This mean that the air close to the element will be very cool and therefore can not hold alot of water, we get water condensating out and the air is dried.If we instead has less heat to transport we can have a warmer cooling element and the air close to the element will be warmer than the case above and we therefore do not dry out the air to the same extent.

An AC unit need to work fast! othervise people will complain. Therefore they operate with "very" cold elements and thereby dry the air alot.

I would prefere a well isolated (small losses) cabinet were I could use a not so cold cooling element. This would prevent the air for drying out to much and the temperature variations should be slower.

I hope that someone find this useful and that it have not been to complicated or to unstructured.

/Magnus