Super-Heat and the P&H Diagram
Adding more heat to a gas increases the temperature of the gas above its saturation temperature (the temperature in which it boiled into a gas). The temperature increase, or difference between the saturation temperature and the new temperature, is called super-heat.
On the 410a cycle below, the refrigerant has gone through the latent process (boiling) in the evaporator and had extra heat added to raise it 10 more degrees, most which, was added in the final stage of the evaporator.
The added super-heat was about 3.5 Btu/minute of added enthalpy, or about a 4% cost to the system over the cooling capacity.
The super-heat adds heat to the compressor and raises the over-all discharge temperature.
So, it would seem less superheat would be better.
Liquid refrigerant will destroy compressors. Super-heat protects compressors from liquid refrigerant at a very small cost to over-all performance.
Note: heat in the compression process is cumulative, too much super-heat will also be detrimental to the compressor causing over-heating. Manufacturers publicize the maximum allowable inlet temperature for their specific model compressors, if that isn’t available, keep it below 30 degrees.
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I worked for over thirty years in the HVACR industry. I have designed, installed, serviced, and trouble shot units of various types throughout the years. The posts here are information based on that experience, I hope you find them useful. If you have a different experience, please comment.