HVAC SUPERHEAT AND SUBCOOLING EXPLAINED! SIMPLE AND EASY!

Latent heat is the change of state of state of a solid, liquid or vapor without a change of temperature.
For example at around the mid point of our evaporator, our refrigerant boils and changes state from a liquid into a vapor.
This change in state is called latent heat.
This is latent heat of vaporization.
In the condenser, we have latent heat of condensation where we change state from a vapor and into a liquid.
Our refrigerant has changed state but we did NOT have a change in temperature.
This change in state can be calculated in BTU's but that will be postponed for another lesson on "WHAT IS A BTU"
So now we know what latent heat is, we can move onto saturation temperature.
Saturation temperature is the temperature at which latent heat occurs.
For example, R-22 has a boiling point temperature of -40 degrees F. at 0 PSI.
At -40 degrees F. R-22 is a liquid and when latent heat of vaporization occurs and we change state from a liquid into vapor, we are still at -40 degrees F.
Most of us are aware of a P/T chart which is a Pressure/Temperature chart.
The temperature we match with the corresponding pressure is infact our saturation temperature.
A P/T chart can also be referred to as a saturation chart. (SHOW P.T CHART)
Pressure and temperature has a direct correlation, As temperature rises or drops, so does the pressure.
Since now we know what latent heat is as well as saturation temperature, we can now understand what exactly is superheat & subcooling.

Superheat is the temperature ABOVE its saturation temperature and subcooling is the temperature BELOW its saturation temperature.
Another meaning for saturation temperature is BOILING POINT.
Saturation temperaure IS the boiling point.
Superheat can be found on the suction line AND the discharge line as the temperature increases down each of those lines either leaving the evaporator or leaving the compressor.
When a manufacturer recomends a certain range of superheat, they are reffering to the suction line superheat.
Subcooling can be found on the liquid line once the refrigerant condenses and exits the condenser.
In my next video I will explain further on why superheat and subcooling are important as well as how to find and calculate them.
So bascially, superheat is just the temperature above the saturation or boiling point temperature and subcooling is the temperature BELOW its saturation or boiling point temperature.

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