On 6/21/2023 at 9:13 AM, Koi Guy said:

Question: I'm wondering what passive condenser units would look like on the PH chart. The case I'm thinking of would be something like an upright freezer with condenser built into the cabinet. I was initially thing that it would just have low efficiency in the valve chamber- but that can't be right. So then I thought maybe compressor design or btu, but just not sure. Or maybe there's nothing done and it's just inefficient. None of my answers seem right. 

You've pretty much got your finger on it. The P-H chart wouldn't really look different on a passive condenser unit, because the engineers would adjust factors to compensate for the slower heat dissipation. Specifically, they can adjust the capacity of the compressor or the amount of refrigerant in the system.

It all comes down to how many BTUs/hour the system can move. And that's directly affected by how much refrigerant is in the system. More refrigerant = more capacity to absorb heat, since heat is just molecular vibration. The more molecules you have that can vibrate, the more heat you can store.  BTUs/hour is also affected by how much of the refrigerant gets moved through the system with each stroke of the compressor.

There's a lot of math involved here that we don't need to get into. It's enough that we can understand in general terms that engineers can adjust one or both of these parameters to make the system meet their needs.