SCIENTIFIC PUBLICATIONS

1. Conference paper: Michael Bantle, Christian Schlemminger, Ignat Tolstorebrov, Marcel Ahrens, Kjetil Evenmo, 2018, Performance evaluation of two stage mechanical vapour recompression with turbo-compressors, Proceedings of the 13th IIR Gustav Lorentzen Conference, Valencia, 2018

Abstract:

Mechanical Vapour Recompression (MVR) is an open loop heat pump system using water (R718) as working fluid, one of the most abundant and safest refrigerant on the planet. The concept can significantly reduce the energy consumption for steam based processes like drying, pasteurization, evaporation or distillation but also for steam production itself. However, the compression technology is commonly not cost efficient especially for small scale productions in the capacity range from 500 kW to 4 MW.  A two stage turbo-compression system was developed and tested based on mass produced automotive turbocharger technology. The turbo-compressor of the first stage reached a pressure ratio of 1.68 and is designed for a mass flow of 400-600 kg/h superheated steam. The second stage turbo-compressor had an identical design and achieved a pressure ration of 1.72. Between compression stage one and two de-superheating is applied by water injection. With the developed system it is possible to compress superheated steam from atmospheric pressure to above 2.9 bar, where it can be condensed at a temperature of 132°C. The COP of the performed investigation was 7.8, when the achievable condensation energy is compared to the total amount of energy supplied to the system. Without the losses in the inverters, motor and gearbox the COP is 9.4, which is the COP when only the isentropic losses of compression are considered. This means that the isentropic efficiency is around 70% of the Carnot efficiency and the system efficiency is still 58% of the Carnot efficiency, even when all loss are considered.

The conference proceedings are available for purchase http://www.proceedings.com/40853.html 

2. Master thesis: Ahrens Ulrich Marcel, 2018, Experimental and numerical analysis of a two-stage turbo compressor system for industrial superheated steam drying, Technical University of Braunschweig 

The aim of this master's thesis was the experimental analysis of the turbo compresso rtechnology performance as well as the development of a numerical turbo compressor model and the evaluation of the two-stage turbo compressor performance. To analyse the performance of the turbo compressors technology, experiments were performed at the test facility developed by SINTEF Energy Research. A suitable numerical turbo compressor model was identified and validated for the development of a system model. The achieved results and experiences were used for the evaluation of the two-stage turbo compressor performance.

The experiments demonstrated a stable operation of the two-stage turbo compressor system. The compressor maps have been created which allow an analysis of the performance and operating range of the turbo compressor. The numerical models were able to reproduce the results in a good approximation and allowed the estimation of further operating points. During this elaboration, the system was able to compress superheated steam from atmospheric pressure to above 3.0 bar, where it can be condensed at a saturation temperature of 133.5 °C. The COP of the performed investigation was 5.9, when the achievable condensation energy is compared to the total amount of energy supplied to the system.

Find the publication on Zenodo - click here.

3. Conference paper: Veronika Wilk, Michael Lauermann, Franz Helminger, 2018, Design zweier Wärmepumpen-Demoanlagen für die industrielle Trocknung (Design of two heat pump demonstration systems for industrial drying), Proceedings of DKV Tagung 2018, 21-23.11.2018, Aachen, Germany 

The paper focuses on the design of two high temperature heat pump systems to be demonstrated first-time in industrial drying applications. The drying processes of the demo sites at Agrana Stärke GmbH and Wienerberger AG are explained with and without heat pump integration, the design questions to be considered are elaborated on, and the two compressors to be demonstrated first-time - a semi-hermetic scroll compressor from Bitzer and a piston compressor from Viking Heat Engines A/S - are presented. In addition, possible refrigerant circuit configurations including their pros and cons are elaborated. Finally, an outlook on the next steps to be taken within the project is provided.

This paper is available in German only. The conference proceedings are available for purchase http://www.proceedings.com/1430.html

4. Conference paper: Michael Bantle, Christian Schlemminger, Marcel Ahrens, Kjetil Evenmo, 2018, Kennfeld und Leistungsanalyse einer zweistufigen Turbokompressor- Brüdenverdichtung (Characteristic map and performance analysis of a two-stage turbo compressor vapour recompression), Proceedings of DKV Tagung 2018, 21-23.11.2018, Aachen, Germany

The paper focuses on the potential of a two-stage turbo compressor vapour recompression for industrial applications and elaborates on the performance data achieved with a novel turbo-compressor developed by Rotrex A/S within the DryFiciency project. The set-up of the lab environment of the mechanical vapour recompression (MVR) system is presented. The characteristic map and performance data of the turbo compressors tested in 2-stages is explained in detail.

This paper is available in German only. The conference proceedings are available for purchase http://www.proceedings.com/1430.html

 

NON-SCIENTIFIC PUBLICATIONS

1. Online brochure: LARGE SCALE HEAT PUMPS IN EUROPE, EHPA's Industrial and Commercial Heat Pump Working Group, 2018

This brochure gives insight about 16 large heat pump applications including one demo site from DryFiciency project, Agrana drying unit. 

Click here to view and download 

 

2. Online brochure: SPIRE projects - Power to your know-how, A.SPIRE, 2016 

Click here to view and download 

 

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