GERMANY: Bitzer has followed up the launch of its six-cylinder Ecoline+ transcritical CO2 compressor at last year’s Chillventa with a four-cylinder version at this week’s Euroshop exhibition.

Like the rest of the series, the four-cylinder Ecoline+ offers high efficiency at both full- and part-load and also benefits from a number of improvements to the series. The Ecoline+ reciprocating compressors are now equipped with new line-start permanent magnet motors (LSPM), an enhanced motor technology offering greater efficiency and mechanical capacity control for transcritical CO2 applications.

This enables systems to be just as efficient for full- and part-load as is otherwise only possible using frequency inverters. Bitzer has also developed a new operating concept with intelligent (IQ) modules.

Describing CO2 as “one of the refrigerants of the future”, Bitzer’s chief technology officer Rainer Große-Kracht said: “With Ecoline+ we have succeeded in making efficient CO2 technology simpler and easier to understand. This is the only way that we can encourage the increased use of this pioneering refrigerant.”

One of the most important innovations in the Ecoline+ series is the enhanced line-start permanent magnet motor, which is said to increase annual performance figures by more than 10%. These robust motors can be directly connected to 50 or 60Hz electrical supplies and offer improved efficiency at both full- and part-load.

Bitzer has successfully tested this technology over the past five years in selected systems in the field. They can be operated both directly on the mains network and with frequency inverters.

Intelligent mechanical capacity control

The new CRII mechanical capacity control for transcritical CO2 applications rivals inverters and permits the operation of Ecoline+ reciprocating compressors with a cooling capacity of between 10 and 100% almost continuously. Four-cylinder compressors are controlled by one or two capacity control pistons, working in a similar way to the familiar capacity control for HFC refrigeration compressors.

The optional IQ module CM-RC-01 ensures optimum efficiency is achieved from the new CRII capacity control system as well as in the supply of oil and operation of the crankcase heater. Using this technology, the new Ecoline+ reciprocating compressors can be easily integrated into a variety of system configurations. Apart from that, the IQ module is said to improve the protective measures as well as the monitoring options for the compressors, allowing them to be used in a wider range of applications.