Thermostatic expansion valve for liquid subcooler

For systems containing a compressor, a thermostatic expansion valve can be used (with standard superheating of 10 K).
The Bitzer Software lists relevant design parameters, for example mass flow and pressure difference (Performance data).

To limit the maximum pressure in the ECO suction gas line, the thermostatic expansion valve should contain an MOP charge (Maximum Operating Pressure).

To activate or deactivate ECO operation, a solenoid valve must be installed in the liquid line upstream of the expansion valve.
Install a sight glass that allows you to check whether bubble-free liquid refrigerant is available at the inlet of the expansion valve.

For the pipe layout and positioning of the valve sensor at the ECO suction gas line, maintain a distance of at least 1 m to the injection position of any additional cooling that may be present, since a mutual influence due to heat transfer is possible!

The valve design for liquid subcoolers is based on the subcooling capacity:

The evaporation temperature is equal to the saturation temperature of the ECO pressure.
To avoid unstable operation when switching on the subcooling circuit and during load variations, valves having a superheat setting of approx. 10 K should be used.
If the subcooling circuit is also operated during part load, this must be taken into account when designing the valve!

Valve design for evaporators:

Due to the strong liquid subcooling, the mass flow is much smaller than in systems of the same capacity without subcooler. This, as well as the lower vapour content after expansion, must be taken into account during the design.