Sharing a Heat Pump for Multiple Uses

April 10, 2021 3:22 PM

We are thinking about adding a chest freezer in the garage. We have also considered adding ductless minisplit AC to a room or three in the house. The thing that turned me off the AC previously was not having a great place for the compressor, but if we're going to get a freezer anyway, I'm wondering if there are any space/energy efficient combo options that could use the same heat pump for multiple applications.
posted by willnot to Home & Garden (3 answers total)

First thought: Check out Technology Connections on youtube for his recent videos on heat pumps. Maybe the less-recent ones, too.
posted by Mister Moofoo at 1:18 AM on April 11, 2021

Best answer: While in theory it would be possible the energy draw of your chest freezer is a small fraction of the draw of a central air conditioning unit. The efficiency of the condensing unit would be very low while only running the freezer.

Also refrigeration equipment generally is optimized for a particular evaporator coil temperature (EG: a freezer might be designed for -20F coil temperature, fridge for 33F and Air Conditioner for 60F). running equipment outside of those ranges is also generally inefficient. Even in large walk in equipment in say a restaurant the freezer and cooler will run separate systems.
posted by Mitheral at 5:02 AM on April 11, 2021 [3 favorites]

It can't do a freezer (well, maybe, but inadvisable), but air-to-water units (like Chiltrix) can have one compressor for multiple applications. Usually the flexibility of being able to move your freezer or refrigerator is more valuable than the small efficiency gain.
posted by flimflam at 11:13 AM on April 11, 2021 [1 favorite]