City, University of London

City, University of London is an independent member institution of the University of London. Established by Royal Charter in 1836, the University of London consists of 18 independent member institutions with outstanding global reputations and several prestigious central academic bodies

City, University of London, Northampton Square London

Compressor and Expander Technology from the Centre for Compressor Technology

managed by City, University of London


Founded in 1995, The Centre for Compressor Technology has focused on advancing the development of positive displacement compressors and expanders, with a special emphasis on twin screw machines. The centre is now world renowned for its work in bringing innovation, design and improvements in the manufacture and performance of screw compressors and expanders that has been pivotal for the market competitiveness of its extensive client base of screw machine manufacturers.


The Centre is open to collaborative industry research projects and can offer license agreements from its extensive IP Portfolio of technologies. The Centre also offer extensive facilities for training engineers in the design of compressors and expanders, including short courses on Compressor Design and Compressor Technology and many more. The Centre for Compressor Technology offers world leading research and development of twin screw machines and compression and expansion technologies. Our vision is to extend the boundaries of understanding of machines for compression and expansion processes and to work with manufacturers in the sector to improve their product performance and reduce costs.
Capabilities of the Centre include:
- Rotor profiling
- Feasibility studies
- Analysis and Performance Prediction
- Basic and Detailed Design
- Grid Generation
- 3D CFD Performance Calculation
A patent portfolio based on the original high performance “N” Profile Rotors has been developed to substantially reduce the operational noise in screw machines whilst maintaining high performance. The patented City “N” rotor profile has been developed as a result of over 30 years of R&D in screw compressor technology. Its advantages over other profiles include:
- Greater flow area for given rotor diameter
- Smaller leakage area and higher efficiency
- Novel “Silent N” rotor with reduced noise
- Lower contact forces and reduced “rotor rattle”
The Centre has developed an extensive range of software to aid the design of compressors and expanders which is continually being upgraded as new knowledge develops.
Manufacturers of compressors and expanders can benefit from the extensive range of services and technology from the Centre for Compressor Technology and thereby improve the performance and competitiveness of their product range with industrially proven capabilities.


The Centre for Compressor Technology provides assistance for all maunfacturers of positive displacement compressors and expanders and is primarily focussed on twin screw machines


Below is a sample of manufacturers who have been clients of the Centre for Compressor Technology and have benefited from technical expertise and technology licence agreements:
- Holroyd (Rochdale, UK)
- Howden (Glasgow, UK)
- Heliex Power (East Kilbride, UK) (Expander manufacturer)
- Rotorcomp (Germering, Germany)
- Comoti (Bucharest, Romania)
- Kirloskar (Pune, India)
- Elgi Equipments (Coimbatore, India)
- Vmac (Vancover, Canada)
- DV Systems (Barrie, Canada)
- Ingersoll Rand-Trane (WI, USA)
- Gardner Denver (IL, USA)
- Carrier Corporation (NY, USA)
- Dalian Refrigeration (Dalian, China)
- Wuxi Compressors (Wuxi, China)
- JiuYi Machinery Co. Ltd (HangZhou, China)
- Jaecklin GmbH (Augsburg, Germany)
- Bitzer (Sindlefingen, Germany)
- Whipple Superchargers (Fresno, USA)
Applications include as compression, gas expansion, steam expansion and ORC systems for generating electrical energy from waste heat
The Centre for Compressor Technology is open to collaborations, consultancy on design and performance, training, licensing, research and development.

Readiness Level (TRL)

actual system proven in operational environment(The pie chart refers to the entire portfolio contained in the database of the helpdesk)

Technology Readiness Levels (TRL) are a method of estimating technology maturity of Critical Technology Elements (CTE) of a program during the acquisition process. The use of TRLs enables consistent, uniform, discussions of technical maturity across different types of technology.

Patent Grading Report

Patent Grading Report

The Grading Patents Report evaluates and grades US patents

Sample Buy from Wisdomain


Current status

PCT Application


Available for



Professor Ian Smith, Professor Nikola Stosic, Professor Ahmed Kovacevic


Case manager: Dr Carol David Daniel

EU-Japan Centre
European CommissionMeti