Mini split a/c in cold climate?

[AkThunderFunk]

I built a new cabinet in my garage that I'm hoping to move my girls into. It's going to be a sealed environment with Co2, my only concern is the a/c unit. Want to go with a mini split, but where I live it is very cold in the winter. Usually around 0°F. But there always a few weeks a year that get between -10° and -30°. Has anyone ever used, or heard of someone using a mini split in cold climates? Do they still work well enough, or just shut down?

 

[Robert Celt]

Hello AkThunder

There are models (companies) that produce mini-splits that will work down to -13F (-25C) after which they start to lose efficiency.

 

[AkThunderFunk]

Thanks Celt. I'll play around tonight and try to fund out which companies make cold climate a/c. You said they just lose efficiency? But they still work at lower then what the are rated?

My other option is put the glass back on the air cooled hood during the colder months. On days I notice it's below zero, turn off the a/c and turn on a fan that pulls air from outside the grow room, through the lights and then just exhaust. The glass never seals 100% so I'd use a little bit more Co2 those days. The a/c shouldn't have a problem starting back up when it gets above zero again should it?

 

[Robert Celt]

Check Fujitsu and LG, I think they are the 2 top brands for low temperature operation. I haven't one yet myself but intend to get one in the next year.

 

[iwltfum]

I run my a/c's until it gets down to about 5-10f outside and then I don't need to run them anymore because they lights heat my garage to 70-80f, but they usually work fine in the single digits. I took all the glass out of my hoods too. For me, it works better that way in the winter than in the summer. I usually have to run a heater even while the lights are on if it get's below -10f or so.

 

[JerryAllen]

How much heat your air source heat pump can transfer into your home depends on the outdoor temperature. As the outdoor temperature drops, so does the heat output of your air source heat pump. Here is an example of the heat output in Btu/hr of our air to water heat pump at three different outdoor temperatures.

When outdoor temperatures drop too low, your heat pump will need to rely on back-up heat to keep your home warm. For mini-splits, the back-up heat is usually an external type of heat like electric baseboard heaters. For air to air heat pumps, the backup heat is in the form of electrical resistance heaters right in the ductwork, and for our air to water heat pump, the backup heat is electrical elements in the buffer tank. Here’s an example of how the backup heat process works

When the temperature in your home drops below the setpoint, stage one of your heat pump is activated to bring the home back up to the set point. In mild weather, stage one would be sufficient. If the weather is colder and stage one isn’t enough, and the temperature in your home drops a further 2°C, stage two will be activated. On most winter days, an air source heat pump running on stage two will be enough to satisfy your home’s heat load. If the weather outside is truly frigid and the temperature drops another 2°C, stage three will be activated. Stage 3 is the backup electrical heat.

It’s also important to note that when temperatures outside drop very low (for Nordic air source heat pumps -8°F or -22°C) the air source heat pump will automatically rely 100% on backup heat. This is to protect the compressor from the increasingly large temperature spread, which causes premature wear and tear. To find out how often you’ll be relying purely on backup heat in the winter, check your area’s historical averages for the previous year. For example, in Halifax NS, temperatures dropped below -22°C only three days in 2014.

Backup heat is more expensive than an air source heat pump or geothermal heat pump because it is less efficient. If you’re relying on backup heat too much (which can happen if the heat pump is too small), you heating bill will be more expensive than you’d planned, so it’s important to do your research and find out how large your system should be and when you’ll be relying on backup heat.

 

[TurboBucket]

Nice necropost