AusBonsai

I'm looking for advice on building and operating a refrigerated glasshouse for a couple of trees that need a cooler climate (approx 5 degrees cooler) than I have.

I figure the basics are double glazed windows, cooling system, fan, auto opening window for ventilation when cooling is not required, programmable thermostat.

Good luck! If you can do it well, I can copy your work and skip all the prototype foofaa I'd really like to have a little glass house indoors.

If we google "how to build a florist fridge", we find a Cool Bot device. This affects temperature and humidity in a way which ought to be very similar for keeping live plants. A florist's fridge seems to be the closest small business equipment which parallels our aim here. However, letting the sun shine in is a big difference.

I expect the ambient temperature will vary by season. If so the chamber won't need an auto window. Simply check the temperatures online, and use an ordinary window.

How committed are you to personally competing each step the full project?

If you have a split air conditioner, it would essentially be a small greenhouse which you can buy of kogan (that’s what I did for my orchids) and have a small refrigerated air control head (could be a bit pricy) with the air conditioner switch connected to a temperature controller for about $50. I use an ink bird temperature controller albeit that’s to heat things up so use a heater.

Just live in Canberra currently -5.3deg C

Project complete. Walls and roof are 10mm twin wall polycarbonate (from Bunnings), floor insulated with 50mm building styrofoam (Bunnings), sits on top of a chest fridge / freezer, hole in floor to connect poly house with freezer, fan to circulate air, Heatermate timer thermostat operates freezer to maintain desired temperature, auto opening greenhouse windo openers.
Air con unit not used as they can only go to 16 degrees; I'm aiming for 0 degrees overnight in mid-winter.

Have you got any pictures of the set up you have done?

Here's the completed unit.
Freezer sits underneath.
Front wall hinged at base to open front. End windows hinged at top and have temperature sensitive auto openers on them.

If I was doing it again I'd use a bigger freezer and smaller top to ensure its cold enough. Current version may just make the grade (300l freezer and 2 M3 space). Expect I will need to add overnight insulation blanket; still sorting out the setup.

Must say that is smart setup

That's impressive. I'm assuming the freezer isn't designed to run outdoors, have you thought about how it will cope with heat or severe rain / wind? Have you checked if there's a maximum operating temperature on the freezer unit?

I'm very curious what species you are wanting to grow that motivated the project.

Did you ever consider using a grow light inside a standing refrigerator /freezer unit? Just thinking if you can keep it inside a house it will require less electricity to keep cool.

Thanks for sharing. Always love a good project

And I thought I was crazy . I hope that beautiful cedar appreciates your efforts . Are you going to run it all year or just in the winter months ?