Cool vivarium – an even cooler installation

Air conditioning installationPerhaps it was wishful thinking believing that I was going to be able to cool the new cool vivarium all summer only with the help of outside air. But not really… we normally do not have such nice weather. I am not complaining mind you, it really is taboo to complain about “nice” weather in Sweden. It has been very warm here lately and last night I actually installed a small portable air conditioner for cooling the cool vivarium. So there you have it, the orchids finally have it better than we do…

I might have managed without installing the AC unit. Many of the orchids are actually thriving in there right now, but others have started to show signs of stress. So I have been debating back and forth for over a week weather to go for it or not, but when my prized Telipogon campoverdei dropped two of the three buds that were forming the decision was made for me. The past few weeks temperatures have soared up to 30°C and the cool viv has been anything but cool… Luckily nighttime temps still drops noticeably, but I had hoped that the nighttime cool would linger a bit longer into the day than it does right now.

Temperatures in the cool viv have been around 25-27 durning the day and about 18 at night the past few weeks – nowhere near cool!! Cool growers really prefer an average of 15-21 during the day and 10-13 degrees at night. But even in the real cloud forest temperatures occasionally go well above this during the day, but nights generally remain cool – and this is the key!  The reason my orchids are actually still doing OK is in fact due to this diurnal temperature difference of about 10 degrees that I get.

With the new AC unit I will be able to control the temperature much better. It is not very powerful, only 6000 BTU, but it does not have to be since it is going to be cooling such a small area. The main thing was that it had to have was a mechanical switch so I can hook it up to an external thermostat and timer. Many of the more advanced AC units come with digital switches and built in thermostats and timers. This would not work for my setup since the unit will be in the warm room outside the vivarium where the temperature sensor would be useless. My Bozz ACR6000 portable air conditioner simply comes with one big button that you turn from off to low or high, that is it.  It is also fairly small and since space really is of a premium in my growing room that was an extra bonus.

Installation was really easy. First dear husband helped me install an adjustable closer for the window closest to the viv. Then we installed the included plastic cover plate in the window (ehm… we just used duct tape and tension from the window closer for this job). Next we ran the included exhaust tube out the window and hooked up another ventilation duct tube (the kind you use for kitchen fan installations) into the cool air intake already in place on the vivarium. Done. Well, we had to rig (duct tape again) a mounting plate to attach the cool air tube to the front exhaust, but that was really it.

I have ordered a Lucky Reptile Thermo Control PRO II to handle the regulating part. The good thing about this particular digital thermostat is that it has two temperature circuits allowing you to set different temperatures for day and night. It also has a built in minute timer for on/off functionality and you can switch between heating and cooling modes. The maximum load is 1000W which is more than most other hobby thermostats I have seen, an important feature since the AC pulls up to 850W. The idea is to use the thermostat both for both the AC in the summer and for the cool air intake fan the rest of the year, making sure it does not get too cold in there in the deep of winter either. I turned it on and it brought the temperature inside the viv down from 24-28 degrees to about 15-16 in about an hour. Stay tuned for more reports.

Here are some more specs for the rest of you technology freaks out there… air flow: 180 m3/h, applied area: 10-12m2, cooling: 1.76 kW/6000 BTU, refrigerant: R410a,  noise level: <55dB, power consumption: 850w/3.8 A, temperature range 0-50°C, dimensions: 28x63x38 cm, weight: 19kg.

Air conditioning installation - window latchAir conditioning installation - hot air exchaustAir conditioning installation - cool air intakeAir conditioning installationAir conditioning installation - the dialAir conditioning installation - cover plate attachment for the cool airAir conditioning installation - temperature check

About the Author:

Karma is an environmentalist, hiking zealot and orchid nerd from Sweden. She is also a designer/art director and a blogger. She has been the editor for the Swedish Orchid Society magazine, published internationally and held lectures on orchid culture. At the moment Karma is a digital nomad, intent on discovering the world one trail at a time.

2 Comments

  1. Wouter July 7, 2010 at 00:53 - Reply

    Heya, I am in the process of building a cool vivarium myself and have been following the construction journal with great interest =)
    Im curious as to how the AC unit influenses the humidity inside the tank, do you mist more frequently now?

  2. Karma July 7, 2010 at 08:26 - Reply

    Hi Wouter, nice to hear that my build can be of help/inspiration. 😀
    About the humidity… well, I have not noticed much of a difference at all really… RH is maybe 5-10% lower after running it, but it’s still well above 75% in there without having to mist more often. However, the AC draw the warm air from the room, not the viv, so the room on the other hand is getting a bit lower RH in the process, but the windowsill orchids will just have to manage in the summer…. it’s all a matter of prioritizing you know. 😉

    Good luck with your build!

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