Publications associées à Safety issues of a CO2-based System in NEST

Flow Boiling of Carbon Dioxide at Different Channel Orientations for the Thermal Management of Future Detector Technologies at the High-Luminosity Large Hadron Collider at CERN

The global warming potential (GWP) of working fluids in thermodynamic cycles and their environmental impact have been gaining considerable attention within the recent years. The global objectives on climate protection are becoming increasingly ambitious, w ...

EPFL2022

Thermal management of components for high energy physics experiments and space applications

Timothée Robert Sophus Frei

High-energy physics (HEP) experiments and space missions share a common challenge: thermal management in harsh environments. The severe constraints in both fields make cooling of electronic components a major design concern. This thesis aims to develop hig ...

EPFL2021

Multi-objective optimization and exergoeconomic analysis of a continuous solar-driven system with PCM for power, cooling and freshwater production

Hossein Pourrahmani

In this article, three different modes of a novel integrated system would be evaluated by the application of high temperature Thermal Energy Storage (TES) to produce electricity, cooling, and freshwater. Freshwater is produced using the reverse osmosis (RO ...

Elsevier2020

Scale limitations of gas bearing supported turbocompressors for vapor compression cycles

Jürg Alexander Schiffmann

An analysis of single-stage centrifugal compressors supported on dynamic, gas lubricated bearings for driving vapor compression cycles suggests that the maximum feasible compressor power is limited, primarily by the bearing load capacity, in the range from ...

2020

Fifth generation district energy systems for low carbon cities

Raluca-Ancuta Suciu

The focus and challenge for energy engineering in the context of rapid climate change is summarised by the Europe 20-20-20 targets, committing to a reduction in energy consumption of 20%. The most logical approach to achieve these goals is to target the mo ...

EPFL2019

Experimental Performance of Completely Passive Single and Recirculating Loop Thermosyphon Cooling Systems using Low GWP R1234ze and R1234yf

John Richard Thome

This paper proposes a novel concept for a loop thermosyphon cooling system, designed for the transistor module of a transformer. The thermosyphon uses a free convection cooled condenser, making the system completely passive, i.e. no energy consumption is n ...

IEEE2019

Optimal heat pump integration in industrial processes

François Maréchal, Maziar Kermani, Anna Sophia Wallerand, Ivan Daniel Kantor

Among the options for industrial waste heat recovery and reuse which are currently discussed, heat pumping receives far less attention than other technologies (e.g. organic rankine cycles). This, in particular, can be linked to a lack of comprehensive meth ...

2018

Small, High-Speed, Oil-Free Radial Turbo-compressors for Cooling Applications: Refrigerant Selection

Jürg Alexander Schiffmann

Emerging energy-efficient, oil-free radial centrifugal compressors seem promising for small to mid-capacity air conditioning and refrigeration applications. Compressor design must balance trade-offs among impeller diameter, bearing type, and refrigerant se ...

2018

Integration of CO2 networks and Power to Gas for emerging energy autonomous cities in Europe

Luc Girardin, François Maréchal, Raluca-Ancuta Suciu

CO2 is used more and more as a refrigerant in the commercial and food retail industries and a majority of experts believe that its share in the field of residential heating, commercial refrigeration and mobile air conditioning across Europe will be higher ...

2017

A general superstructure for the optimal synthesis and design of power and inverse Rankine cycles, 27th European Symposium on Computer Aided Process Engineering

François Maréchal, Alberto Mian, Emanuele Martelli

This work presents a very general superstructure capable of reproducing any configuration of Rankine cycles, both power cycles (steam cycles we well as Organic Rankine Cycles) and inverse cycles (refrigeration cycles or heat pumps), as well as heat/steam d ...

Elsevier Science2017

Theoretical analysis of steam generation methods - Energy, CO 2 emission, and cost analysis

Jürg Alexander Schiffmann

A theoretical case study on steam generation has been performed. Different methods of producing steam by vapour compression, direct electrical heating, gas heating, heat pumping, use of waste heat, and a mixture thereof, were theoretically analysed. The fi ...

Elsevier2017

Turbocompressors for Domestic Heat Pumps – A Critical Review

Jürg Alexander Schiffmann, Jean-Baptiste Carré

Small-scale, oil-free radial compressors on gas lubricated bearings represent a promising alternative to state-of-the-art compressor technology for driving domestic sized heat pumps. The inherent characteristics of turbocompressors manage to fit the heat p ...

2017

ORC Driven Heat Pump Running on Gas Bearings for Domestic Applications: Proof of Concept and Thermo-Economic Improvement Potential

Jürg Alexander Schiffmann, Violette Mounier

ORC driven Heat Pumps (HP-ORC) offer a promising technology of thermally driven heat pumps (TDHPs) for domestic applications. Recently, a 40 kW HP-ORC unit based on gas supported turbomachinery has been investigated in which the ORC radial turbine drives t ...

2017

Experimental investigation of a two-stage oil-free domestic Air/Water heat pump prototype powered by an oil-free high-speed twin-stage radial compressor rotating on gas bearings

Jürg Alexander Schiffmann, Daniel Favrat, Jean-Baptiste Carré

Domestic heat pumps have been identified as a key-technology to decrease the energy consumption of the domestic sector, which represents 29% of the world final energy consumption. Space & water heating represent more than two third of the domestic sector e ...

2016

Multi-temperature heat pumps: A literature review

Jürg Alexander Schiffmann

This review highlights the major advantages and challenges of mechanically driven heat pumps and refrigeration systems with focus on multi-temperature applications. Different design strategies are presented, including cycles with multi-stage compressors, e ...

Elsevier2016

Experimental investigation of electrical domestic heat pumps equipped with a twin-stage oil-free radial compressor

Jean-Baptiste Carré

The world energy consumption has dramatically increased since the end of the World War II. The main share of this energy comes from fossil fuel combustion. The worldwide domestic sector consumes about 30% of the global energy supply and the biggest share o ...

EPFL2015

Modeling and Experimental Investigation of an Oil-Free Microcompressor-Turbine Unit for an Organic Rankine Cycle Driven Heat Pump

Jürg Alexander Schiffmann, Jonathan Demierre, Antonio Rubino

Domestic heating and cooling will more and more have to rely on heat pumps (HPs) in order to support a more rational use of primary energy consumption. The HP market is mainly dominated by electrically driven vapor compression cycles and by thermally drive ...

American Society of Mechanical Engineers2015

Experimental investigation of a Thermally Driven Heat Pump based on a double Organic Rankine Cycle and an oil-free Compressor-Turbine Unit

Jürg Alexander Schiffmann, Daniel Favrat, Jonathan Demierre, Johannes Wegele

This paper presents the experimental investigation of a concept of Thermally Driven Heat Pump (TDHP), based on the coupling of a vapor compression heat pump cycle and an Organic Rankine Cycle (ORC). The studied concept uses a single stage centrifugal compr ...

Elsevier2014

Methodology for Identification of Suitable ORC-Cycle and Working-Fluid using Integration with Multiple Objectives

Daniel Favrat, François Maréchal, Matthias Bendig

In recent times the interest in electricity production with Organic Rankine Cycles (ORC) has increased. A look into recent publications shows that the identification of suitable working fluids is in general done by a look at a more or less small number of ...

Aidic Servizi Srl2014

Dynamic flow control and performance comparison of different concepts of two-phase on-chip cooling cycles

John Richard Thome, Jackson Braz Marcinichen, Duan Wu, Bruno Michel

A hybrid on-chip two-phase cooling cycle specifically designed to cool server boards with chips of high performance computers was experimentally evaluated considering steady-state and transient operation of two parallel pseudo-chips and auxiliary electroni ...

Elsevier2014