You absolutely could implement a turbine rather than an orifice to drop the pressure of the fluid in a phase change cycle, and in doing so you would recover some energy that is otherwise lost. However the added complexity and maintenance overhead is not worthwhile in many real world situations such as domestic refrigerators.

Thermodynamic efficiency is only one of several competing criteria. Another commenter already mentioned that the size of heat exchangers is massively lower in a system with liquid than a purely gas heat cycle. This is far more important than you might think, given the packaging constraints of say a domestic refrigerator.

Expanders are essentially compressors run in reverse (in fact can be made modified from such) and recover some energy. They aren’t used in many applications because the work recovered doesn’t make up for the cost and potential maintenance needs etc

Most of the time when you expand via a valve in a refrigerant cycle you expand into the two phase region from a subcooled state. Expanding a liquid does not give us a lot of energy back. With co2 as a refrigerant there are ideas to use an expander to raise the efficiency of the cycle. But that's a special case as co2 has a flat saturation curve where we have a high vapor content while expanding. Also, expanding while having liquid content in the fluid can damage most expanders.

In many domestic refrigerators we do recycle a bit of heat. The external areas around the door gaskets are colder, and prone to a buildup of condensation if you don't heat them up somehow to match the rest of the exterior. We can and on occasion do put electric heaters there, but the best solution when possible is to simply route the starting section of the condenser (where the gas temperature is pretty high) through those areas. Bad move from a heat pump efficiency perspective since some of that heat leaks back into the cold side, but good for the efficiency of the appliance as a whole.

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