Project Overview

Howden and City, University of London’s Centre for Compressor Technology are currently working on a 5-year collaborative project - Smart Efficient Compression, Reliability and Energy Targets (SECRET) - which is supported by an award from The Royal Academy of Engineering (RAEng) and led by Howden Chair in Engineering Design and Compressor Technology, Professor Ahmed Kovacevic.

This partnership specifically looks at the effect of clearances and heat transfer dynamics within the compressor and the resultant reduction in losses and gains in efficiency. 

This project also contributes to advances in the development of Industry 4.0, in which the team seeks to transform traditional manufacturing and industrial practices with the latest smart technology. To realise this, the project will focus on the short-, medium- and long-term development of Howden's oil free screw compressors range.


Year One Achievements

  • Phase One of the project has been dedicated to understanding the physics of the flow within clearance gaps of rotating positive displacement machines which will improve the efficiency, performance and reliability of oil free screw compressors

  • Over the past year, our team have worked tirelessly to setup the foundations for future success. To do this, we have opened state of the art laboratories to understand the physics and provide the data for validation of our high fidelity computational fluid dynamics

  • We demonstrated world leading measurement, modelling and experimental techniques.

  • The work we have accomplished in the past twelve months now determines the direction of research we will undertake throughout the next four years

Having both teams involved in phase one, ensures the project delivers outcomes that are valuable to industry, fit for purpose and directly makes a real world impact by reducing energy consumption.


Howden introduced oil injected screw compressors in the 1950’s, and developed new technologies to extend the range of such machines. Today, the company offers over 700 variants of screw machines for numerous applications, including oil and gas, refrigeration, air conditioning, and processed gas. I am proud to have been closely allied with Howden for more than 12 years jointly introducing new rotor profiles and compressor sizes, which continues to serve their customers with better and more efficient machines.

The Centre for Compressor Technologies which I direct at City, University of London is a world-leading research institute for these types of machines. With the support of Howden and the Royal Academy of Engineering, this project is destined to result in novel, more efficient, and reliable oil free machines. I am very excited about this opportunity.

Professor Ahmed Kovacevic

Meet the Team

The SECRET team is comprised of experts in their field. Come meet them.



Major Expected Outcomes

This project is a continuation of the solid partnership between Howden and City, combining 30 years of research on screw compressors with Howden's market-leading technology, which is targeted at reducing leakages in rotating machinery by 20%, and improving the efficiency of oil free screw compressors by 2%, thus contributing to the European Union’s Global Net Zero CO2 emissions targets. All industrial and academic sectors which deal with oil-free rotating machines, such as power recovery systems, food and pharmaceutical industries, vacuum pump applications and others will benefit from the knowledge, developed methods and devices built by this project. The UK public at large will benefit from the lower carbon footprint of these smart energy efficient systems, leading toward the net zero emission initiative and the wealth-creation with new jobs stimulated by this innovation.

1. Test facility and validated numerical methods of heat-flow-solid interactions in clearances

2. Scaled-down compressor prototype with novel rotor profiles and smart clearance management system

3. Industrial prototype with integrated remote monitoring and self-regulating systems for minimization of energy consumption and increased reliability


Project Schedule

The project will be undertaken over 5 years, consisting of 3 stages divided into 16 separate work packages. The schedule includes key milestones such as:

  • Understanding physics
  • Building a prototype for concept validation
  • Building the commercial prototype

You can learn more about the project on the University of London page dedicated to the SECRET project


Research excellence and intensity at heart

Download your copy of the SECRET Project brochure


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Learn More about our Oil Free Screw Compressors

Oil Free Screw Compressor

Enter our global headquarters for Screw Compressor technology : the Renfrew Manufacturing Campus, and learn more about our Oil Free Screw Compressor range.


Grant received from RAEng

Howden and City, University of London secure grant from the Royal Academy of Engineering to develop novel energy efficient compression technologies


Nuclear fusion research project

Howden to supply world leading oil free screw compressor technology to the international nuclear fusion research project ITER in France

Project SECRET White Papers

Project SECRET - A Novel Experimental Setup

Screw Compressor

A Novel Experimental Setup to Measure Velocity and Temperature Field in Leakage Flows of Oil Free Rotary Positive Displacement Machines

Project SECRET - Application of Path Homotopy

Screw Compressor

This work explores application of an idea called ‘Path Homotopy’ from Topology in twin screw compressor rotor profile design.

Project SECRET - Bi Directional System Coupling

Screw Compressor

Oil-free twin-screw compressors are essential in various industrial applications where clean compressed gas is required.

Project SECRET - CFD Analysis

Screw Compressor

Due to the sharp discontinuities in the profile of hook and claw pumps which make it difficult to produce a good quality body fitted mesh, their CFD simulations are challenging

If you would like to submit an enquiry please get in touch.