Refrigeration 101

[Gary]

I apologize for the confusion. It seems further clarification is needed here:

Subcooling is the cooling of liquid below saturation. In order for this to occur the liquid must be subjected to a temperature that is below saturation.

In order for the subcooling to be 15F/8.5K the liquid must travel through an area where the temperature is at least 15F/8.5K below the SCT or the desired subcooling cannot be achieved.

If the receiver outlet is directly in the path of the air leaving the condenser, then the surrounding air is not cool enough to sufficiently subcool the liquid.

In this case, the liquid line temperature must be measured further downstream where the surrounding air is cooler.

Similarly, in order to achieve sufficient superheat at the TXV bulb the vapor must travel through an area where the temperature is sufficiently high to cause that superheating. If the suction line is directly in the path of the air leaving the coil, then the surrounding air temperature will not be warm enough to achieve the desired superheat.

Hope this helps end the confusion.