Integration into the refrigerant circuit

Dimensioning of pipes

Suction gas lines must be carefully dimensioned. Minimum gas velocities must be maintained even during part load operation to ensure oil return. The guideline values are 4 m/s in horizontal pipes and 8 m/s in vertical pipes. However, this must be checked individually for each system.

Pipe layout

To ensure constant oil return, rising lines on both the suction and the discharge gas side must often be divided into two separate sections. The pipes must then be routed in such a way that, at part load, one of the two pipes is closed off by a column of oil and the gas flows only through the other pipe. This pipe must be adequately dimensioned so that the minimum velocity required for oil return is reached.

In systems with several evaporators or evaporator sections that can be shut off by solenoid valves, the individual suction gas lines may only be combined in a common line after any existing rising pipe sections. In the case of widely branched pipe networks, an additional oil separator is recommended for medium and low temperature systems.

Evaporator and expansion valve

Sufficient superheat and stable operation must be ensured in both full and part load. Depending on evaporator design and capacity range, it may therefore be necessary to divide the system into several refrigerant circuits. Each circuit has its own expansion valve and solenoid valve and can be adapted to load conditions with the appropriate control.

Parallel compounding