Publications related to Chiller

Vapor compression and energy dissipation in a collapsing laser-induced bubble

Mohamed Farhat, Danail Obreschkow, Davide Bernardo Preso, Armand Baptiste Sieber

The composition of the gaseous phase of cavitation bubbles and its role on the collapse remains to date poorly understood. In this work, experiments of single cavitation bubbles in aqueous ammonia serve as a novel approach to investigate the effect of the ...

Aip Publishing2024

Violation-aware contextual Bayesian optimization for controller performance optimization with unmodeled constraints

Colin Neil Jones, Wenjie Xu, Bratislav Svetozarevic

We study the problem of performance optimization of closed -loop control systems with unmodeled dynamics. Bayesian optimization (BO) has been demonstrated to be effective for improving closed -loop performance by automatically tuning controller gains or re ...

Elsevier Sci Ltd2024

Selection and Optimal Use of Nanoporous Materials for Adsorption Energy Technologies

Emanuele Piccoli

Due to the large waste of heat in the power and industrial sectors, our use of energy is inefficient. Moreover, it relies on rapidly depleting and greenhouse-gas-emitting sources such as fossil fuels. While the scarcity of energy resources is a relevant so ...

EPFL2023

Pressure-freezing of dodecane: exploring the crystal structures, formation kinetics and phase diagrams for colossal barocaloric effects in n-alkanes

Tomasz Poreba

Barocaloric (BC) materials provide cheaper and more energy efficient alternatives to traditional refrigerants. Some liquid alkanes were recently shown to exhibit a colossal BC effect, matching the entropy changes in commercial vapour-liquid refrigerants. D ...

Royal Soc Chemistry2023

Design and management of three-dimensional multi-processor systems-on-chip with integrated flow cell arrays

Halima Najibi

Three-Dimensional Multi-Processor Systems-on-Chip (3D MPSoCs) are promising solutions for highly intensive Artificial Intelligence (AI) and Big Data applications. They combine remarkably dense computation capabilities and massive communication bandwidths. ...

EPFL2022

Novel pulsating heat pipe for high density power data centres: performance and flow regime analysis

John Richard Thome, Jackson Braz Marcinichen, Filippo Cataldo, Raffaele Luca Amalfi

With the advancement of technologies such as Artificial Intelligence and 5G telecommunications, where computational rate is constantly pushing its limits, highly efficient and reliable cooling devices are starting to become an overly critical factor. Not o ...

IEEE2021

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

Small-scale organic Rankine cycle turbo-generator for waste heat recovery on truck engine

Kévin Rosset

Truck engine waste heat recovery (WHR) systems have been investigated for many years. Among them, organic Rankine cycle (ORC) systems show the highest potential, but still lack efficient small-scale expansion devices, in practice. Proposed expanders are of ...

EPFL2020

Water-energy nexus approach to compare performance of evaporative and vapor-compression cooling systems

Dolaana Khovalyg, Amirreza Heidari, Nasim Soori

Evaporative cooling systems consume high water, but low electricity for their operation. On the other hand, vapor compression systems consume no water, but high electricity. Water and energy systems are interconnected at different levels. Therefore, water ...

2019

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

Experimental Characterization of Different Condenser Technologies in a Passive Two-Phase Cooling System for Thermal Management of Electronics

John Richard Thome, Jackson Braz Marcinichen, Chiara Falsetti, Raffaele Luca Amalfi

Passive two-phase, micro-channel cooling for thermal management of electronics represents an efficient and viable solution to augment conventional air-cooling systems with the potential for higher power dissipation densities, increased reliability, reduced ...

IEEE2019

Enhancing Two-Phase Cooling Efficiency through Thermal- Aware Workload Mapping for Power-Hungry Servers

David Atienza Alonso, Marina Zapater Sancho, Arman Iranfar, Ali Pahlevan

The power density and, consequently, power hungriness of server processors is growing by the day. Traditional air cooling systems fail to cope with such high heat densities, whereas single-phase liquid-cooling still requires high mass flowrate, high pumpin ...

IEEE and ACM Press2019

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

Thermal Interface Material Enablement of Off-Board Two-Phase Cooling

John Richard Thome, Raffaele Luca Amalfi

Two-phase, refrigerant-based cooling offers significant promise for increasing heat densities and energy efficiencies of electronic components. One barrier to wide spread adoption of two-phase cooling solutions is preserving product features deemed essenti ...

IEEE2018

Data-Driven Pre-Design Tool for Small Scale Centrifugal Compressors in Refrigeration

Jürg Alexander Schiffmann, Cyril Picard, Violette Mounier

Domestic scale heat pumps and air conditioners are mainly driven by volumetric compressors. Yet the use of reduced scale centrifugal compressors is reconsidered due to their high efficiency and power density. Recent work has demonstrated the technical feas ...

2018

Methodology for efficient use of thermal energy in the chemical and petrochemical industry

Elfie Marie Méchaussie

The current European energy regulation, aligned with the European Union energy strategy and targets for the next decade, requires large industrial companies to regularly assess their energy performance and implement energy efficiency improvement measures. ...

EPFL2018

Design, modeling and experimental validation of a novel finned reciprocating compressor for Isothermal Compressed Air Energy Storage applications

Alfred Rufer, Mahbod Heidari

Considering the need for a reliable and environmentally friendly energy storage solution for addressing renewable energy intermittency issue and following the developments on Isothermal Compressed Air Energy Storage (I-CAES) systems, a new finned piston co ...

Pergamon-Elsevier Science Ltd2017

Two-Phase Mini-Thermosyphon For Cooling Of Datacenters: Experiments, Modeling And Simulations

John Richard Thome, Jackson Braz Marcinichen, Nicolas Lamaison, Raffaele Luca Amalfi, Chin Lee Ong

Nowadays, datacenters heat density dissipation follows an exponential increasing trend that is reaching the heat removal limits of the traditional air-cooling technology. Two-phase cooling implemented within a gravity-driven system represents a scalable an ...

Amer Soc Mechanical Engineers2017

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

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