Introduction

Adjusting the capacity to the demand of the refrigeration system includes e.g. the differences between summer and winter operation, enables finely tuned capacity in compound systems and increases system COP through more stable and higher average suction pressure.

The following main methods are used for capacity control of compressors:

Variants of mechanical capacity control

This document explains the integrated mechanical capacity control. It is available for many BITZER reciprocating compressors and can be delivered pre-mounted or as retrofit. The following variants exist (CR = capacity regulator):

In any case, special cylinder heads with additional bores are required for capacity control.

Comparison of a standard cylinder head (left) with cylinder heads for capacity control with additional bores (centre and right).
Example for a capacity regulator on a semi-hermetic 6-cylinder compressor 6JE .. 6FE
Example for a capacity regulator on a semi-hermetic 6-cylinder compressor 6JE .. 6FE

Combination of capacity control and start unloading

Also observe the following technical documents

For information and safety instructions covering the entire service life of the compressor, please refer to the operating instructions, among other sources.

For controlling the capacity regulators with the IQ MODULE CM-RC-01 or CM-RC-02:

For schematic wiring diagrams with the different variants of capacity control: