Liquid receiver

[wambat]

Dossat/Horan say, When liquid refrigerant is subcooled before entering the metering device, the refrigeration effect per unit mass is increased. The example given is the heat removed (6.96btu/lbm). for the saturated cycle, in the example, the refrigeration effect per unit mass is 60.38btu/lbmas shown in a proof11.11 in section 11.6. the proof states for the sub cooled cycle, the refrigeration effect per unit mass, is 67.34btu/lb, a difference of 11.53% This is for actual refrigeration cycle
This in turn reduces mass flow rate by 10.27% and since the mass flow rate is less for the sub cooled cycle, it follows that the volume of vaporthat the compressor must handle per unit of capacity will also be less. Going on, the compressor displacement required for the sub cooled cycle is smaller then that required for the saturated cycle because the volume of vapor per unit of capacity is less. so the COP will increase by 11.5% in the example.

[NoNickName]

... so the COP will increase by 11.5% in the example.

This is the example of how books should not be read.
In real life we already have a compressor, a TEV and an evaporator, the three chosen for a given SC.
In case SC is increased, there will be no COP increase and no different mass flow, because the components are still the same.
The net enthalpy gain will become lower evap. pressure, which in turn becomes as a lower compressor suction pressure, and a lower COP.

If the manufacturer declares data with 3°K SC, please stay with that. Any increase in SC will result in poorer performance for a given chiller.

[Peter_1]

....Dossat/Horan say, ..... so the COP will increase by 11.5% in the example.

That's what I thouht and was trying to explain with no so many words.