Efficiency boost for Bitzer screw compressor
13th July 2021
GERMANY: Bitzer is to launch a new high-efficiency version of its CSW compact screw compressor with a new motor and special oil charge.
The CSW85/95 for water-cooled liquid chillers is a combination of the well-known Bitzer CSW screw compressor with a special selected motor version 4. While the compressor has already been introduced into the Chinese market, increasing efficiency requirements and corresponding customer demand, especially from Europe and India, has prompted Bitzer to commence manufacture at its Rottenburg-Ergenzingen site.
Bitzer maintains that CSW enables OEM screw chiller manufacturers to design and produce water-cooled air conditioning chillers that fulfil the highest international energy efficiency standards like the European Ecodesign 2016/2281 tier 2 and the Indian BEE-ECBC – ISEER star rating.
The product range covers nine models with displacements between 410m³/h and 1,120m³/h at 50Hz as well as 495m³/h and 1,351m³/h at 60Hz. Their application envelope was designed for highly efficient water-cooled air conditioning and process chiller applications with maximum condensing temperatures up to 46°C. To achieve this, the motor features increased efficiency in the target application envelope and a reduced maximum operating current. This enables the use of smaller contactors and smaller mains cable diameters, resulting in an overall system cost reduction.
CSW was designed for low-pressure medium and low GWP refrigerants like R134a, R1234yf, R513A, R450A, R1234zeE and R515B. Also, the internal gas flow has been optimised and the internal pressure drop further reduced.
The combination CSW with motor version 4 and the optimised oil version allows for efficiency to meet the specifications, says Bitzer. The company cites the example of a water cooled air conditioning liquid chiller set under European standard EU 2016/2281 where the CSW motor version 4 enables the chiller’s SEER to be improved by up to 8% compared to a standard CSW compressor, at typical motor cooled chiller operating conditions.
The single-slider mechanical capacity control can be adjusted between 100 and 25%. This CSW version is also suitable for operation with an external frequency inverter at a frequency range between 20 and 60Hz.
