Introduction

BITZER screw compressors are in most cases equipped with an additional suction gas connection for operation with an economiser (ECO). This connection allows additional subcooling of the refrigerant through:

• a liquid subcooling circuit (ECO operation with liquid subcooler) or
• a 2-stage refrigerant expansion by means of an intermediate pressure vessel (ECO operation with intermediate pressure vessel for two-stage refrigerant expansion).

This increases not only the refrigerating capacity but also the coefficient of performance. This is advantageous compared with traditional applications in particular at high pressure ratios such as in low temperature systems.