How to measure subcooling

Measuring subcooling and superheat are essential to making sure a system is operating efficiently and safely.
Our video gives a quick explanation of how to measure subcooling (a video on superheat is also available on this channel)
See the IOR RACHP Section Bulletins for “subcooling explained” at ior.org.uk/rachp-publications....
Subscribe to the Section to access these and 100’s other practical bulletins at www.ior.org.uk/membership
#refrigeration #hvac #heatpump #technician #engineering #engineer #subcooling

[@raquelsapalaran2907]

thank you very much for sharing your knowledge.

[@tonyp6088]

Hi there, great demonstration.
If you were to take the liquid line temperature just before the metering device would there be much difference? Would it continue to subcool?

[@instituteofrefrigerationUK]

The reason for taking the temperature of the liquid on the ambient side of the cooled space (e.g. as the pipe enters the cold room) is to calculate the subcooling that has occurred because of the outside ambient conditions. You can measure the liquid line before the expansion device, this would then include the subcooling that has happened due to the liquid line entering the cooled space, care should be taken to ensure the expansion device temperature drop (happening due to the refrigerant expansion) does not influence the temperature of the liquid, line so suggest measuring no closer than 150mm to the inlet to the expansion (metering) device.
The other reason for measuring the pipe on the ambient side is that evaporators can sometimes be difficult to access (loaded room, mounted high on room ceilings etc), whereas you can normally access the liquid line service on the roof or outside of the cooled space.