VRF Heat Pump - Cooling in Low Ambient Temperatures 2

[nuuvox000]

Hello, I have some areas in a building that will be in cooling mode 24/7/365. I was looking at the operating range on the Fujitsu outdoor VRF units and they are only rated for cooling between 23°F to 115°F. Why are they only rated down to 23°F for cooling mode? Wouldn't it cool even better the colder it gets outside? Thanks for your help!

 

[IRstuff]

probably tied to its SEER performance.

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[EnergyProfessional]

The refrigerant gets too cold... you need a differential pressure.

Mitsubishi has units that come with a low-temp kit (baffles to keep the wind away) that are rated to around -20°F. Look at the PKA/PUY models. They also modualte and shut off the condenser fan to keep the refrigerant at a minimum temperature.

 

[IRstuff]

Refrigerant needs enough delta temperature to evaporate in the expander; otherwise, the compressor will be trying to compress something that's mostly liquid, which is REALLY bad for the compressor, and pretty much chews up the SEER.

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[nuuvox000]

Thank you, that helps a lot!