Home

Person

Jürg Alexander Schiffmann

This person has left EPFL

About
Privacy
Disclaimer

Graph Chatbot

Related publications (111)

Page 4 of 6

Thermo-economic optimization of an ORC driven heat pump based on small scale turbomachinery and comparison with absorption heat pumps

Jürg Alexander Schiffmann, Luis Carlos Mendoza Toledo, Violette Mounier

The current paper presents the thermo-economic optimization and comparison, through a multi-objective algorithm, between HP-ORC and the competing single effect absorption heat pump (SEAHP), with the aim to find the best trade-off between investment cost an ...

Elsevier2017

Small-scale turbopumps for waste heat recovery applications based on an organic Rankine cycle, modeling, analytical and experimental investigations

Jürg Alexander Schiffmann, Sajjad Zakeralhoseini

The organic Rankine cycle (ORC) system is considered a promising technology to exploit thermodynamic potential of waste heat. The weight and size of standard pumps can penalize the benefits of installing an ORC system on vehicles. Small-scale ORC applicati ...

EUS Editorial Universidad de Sevilla2024

An Integrated Approach to Designing Robust Turbocompressors on Gas Bearings Through Surrogate Modeling and Constrained Multi-Objective Optimization

Jürg Alexander Schiffmann, Soheyl Massoudi, Cyril Picard

Designing turbocompressors is a complex and challenging task, as it involves balancing conflicting objectives such as efficiency, stability, and robustness against manufacturing deviations. This paper proposes an integrated design methodology for turbocomp ...

ASME Amer Soc Mechanical Engineers2023

Sofc system with anode off-gas recirculation

Jan Van Herle, Daniel Favrat, Jürg Alexander Schiffmann, Zacharie Wuillemin, Patrick Hubert Wagner

The present invention concerns an SOFC system comprising an anode off-gas recirculation arrangement in which anode off-gas is pumped by a fan or pump of a coaxial turbine-fan assembly, the system comprising a condenser for condensing water contained in sai ...

2020

Experimental investigation of a direct driven radial compressor for domestic heat pumps

Daniel Favrat, Jürg Alexander Schiffmann

The presence of oil in domestic heat pumps is an obstacle toward higher efﬁciency, particularly for enhanced surface evaporators and for advanced concepts based on two- stage cycles. Very compact direct driven radial compressors supported on oil-free beari ...

2009

Dated: Guidelines for Creating Synthetic Datasets for Engineering Design Applications

Jürg Alexander Schiffmann, Cyril Picard

Exploiting the recent advancements in artificial intelligence, showcased by ChatGPT and DALL-E, in real-world applications necessitates vast, domain-specific, and publicly accessible datasets. Unfortunately, the scarcity of such datasets poses a significan ...

Amer Soc Mechanical Engineers2023

Data-Driven Predesign Tool for Small-Scale Centrifugal Compressor in Refrigeration

Jürg Alexander Schiffmann, Cyril Picard, Violette Mounier

Domestic scale heat pumps and air conditioners are mainly driven by volumetric com-pressors. Yet the use of reduced scale centrifugal compressors is reconsidered due to their high efficiency and power density. The design procedure of centrifugal compressor ...

2018

Small-scale turbocompressors for wide-range operation with large tip-clearances for a two-stage heat pump concept

Jürg Alexander Schiffmann, Adeel Javed

Two mechanically driven small-scale turbocompressors running on gas lubricated bear-ings have been theoretically designed for a 6.5 kW two-stage heat pump functioning under variable operating conditions. The novelty in the heat pump system lies in the appl ...

Elsevier2016

Effects of humid air on aerodynamic journal bearings

Jürg Alexander Schiffmann, Eliott Philippe Guenat

The development of aerodynamic bearings applications where ambient conditions cannot be controlled (e.g., for automotive fuel cell compressor) raises the question of the effects of condensation in the humid air on perfor-mance. A modified Reynolds equation ...

2018

Haptics based multi-level collaborative steering control for automated driving

Hannes Bleuler, Jürg Alexander Schiffmann, Robert Fuchs, Tomohiro Nakade

Increasing the capability of automated driving vehicles is motivated by environmental, productivity, and traffic safety benefits. But over-reliance on the automation system is known to cause accidents. The role of the driver cannot be underestimated as it ...

2023

A Review of Grooved Dynamic Gas Bearings

Lili Gu, Jürg Alexander Schiffmann, Eliott Philippe Guenat

This paper offers an extensive review of publications dealing with the modeling, the design and the experimental investigation of grooved dynamic gas lubricated bearings. Recent years have witnessed a rise in small-scale and high-speed turbomachinery appli ...

2020

DARTS-NETGAB: DESIGN AUTOMATION AND REAL-TIME SIMULATION USING NEURAL NETWORKS ENSEMBLES FOR TURBOCOMPRESSORS ON GAS-BEARINGS

Jürg Alexander Schiffmann, Soheyl Massoudi, Timothy Horvath, Joseph Bejjani

In the domain of engineering design, where efficiency in simulation and precision in modeling are paramount, this study introduces DARTS-NETGAB, a pioneering platform uniquely designed for real-time simulation and automated design. Specifically tailored fo ...

American Society of Mechanical Engineers (ASME)2024

The Role of Reynolds Number Effect and Tip Leakage in Compressor Geometry Scaling at Low Turbulent Reynolds Numbers

Christoph Schreiber, Jürg Alexander Schiffmann, Markus Diehl

In compressor design, a convenient way to save time is to scale an existing geometry to required specifications, rather than developing a new design. The approach works well when scaling compressors of similar size at high Reynolds numbers but becomes more ...

2020

Comparative Evaluation of Foil Bearings with Different Compliant Structures for Improved Manufacturability

Jürg Alexander Schiffmann, Karim Magdi Zakaria Abdelrahman Shalash

Potential geometrical deviations in bump foil bearings due to manufacturing uncertainty can have significant effects on both the local stiffness and clearance, and hence, affecting the overall bearing performance. The manufacturing uncertainty of bump type ...

Amer Soc Mechanical Engineers2017

Performance potential of gas foil thrust bearings enhanced with spiral grooves

Jürg Alexander Schiffmann, Eliott Philippe Guenat

The upscaling of turbomachinery using gas foil thrust bearings is limited because of their limited load capacity and the thermal issues linked with very thin film thickness. The improvement potential of spiral grooves manufactured on the top-foil of such b ...

2019

Experimental Investigation of Water Injection in an Oil-Free Co-Rotating Scroll Machinery for Compressed Air Energy Storage

Jürg Alexander Schiffmann, Luis Carlos Mendoza Toledo

2014

Two-phase and oil-free co-rotating scroll compressor/expander

Jürg Alexander Schiffmann

This paper discusses experimental and theoretical investigations about a re-designed co-rotation scroll machine, operating in compressor and expander mode. The machine has been tested under various operational conditions, with the aim to determine the infl ...

2019

Parametric Reduced Order Model of a Gas Bearings Supported Rotor

Jürg Alexander Schiffmann, Fabio Nobile, Dimitri Maurice Goutaudier

Gas bearings use pressurized gas as a lubricant to support and guide rotating machinery. These bearings have a number of advantages over traditional lubricated bearings, including higher efficiency in a variety of applications and reduced maintenance requi ...

2023

Integrated design, optimization and experimental investigation of a direct driven turbocompressor for domestic heat pumps

Jürg Alexander Schiffmann

Heating and cooling will more and more rely on heat pumping in order to enable a more rational use of energy. The further development of domestic and small industrial multi-stage heat pumps with enhanced performance is impaired by the presence of oil mixed ...

EPFL2008

Unstable tilting motion of flexibly supported gas bearing bushings

Jürg Alexander Schiffmann, Philipp Kaspar Bättig

This paper presents measurements of the motion amplitudes from flexibly supported Herringbone Grooved Journal Bearing bushings. Measurements taken in four locations on the flexibly supported bearing bushing enable the distinction between the radial and the ...

2022