Refrigeration

Related publications (24)

Increasing the Energy Efficiency of Gas Boosters for Hydrogen Storage and for Refueling Stations

A new electrically driven gas booster is described as an alternative to the classical air-driven gas boosters known for their poor energetic efficiency. These boosters are used in small scale Hydrogen storage facilities and in refueling stations for Hydrog ...

MDPI2023

Numerical and experimental investigation of spiral-grooved gas journal bearings

Elia Iseli

Small-scale turbomachinery is increasingly used in carbon-free energy conversion systems, such as commercial or domestic scale heat pumps, fuels cells for transportation and waste heat recovery. The usage of aerodynamic bearings allows the design of compac ...

EPFL2022

Robust design using multiobjective optimisation and artificial neural networks with application to a heat pump radial compressor

Jürg Alexander Schiffmann, Cyril Picard, Soheyl Massoudi

Although robustness is an important consideration to guarantee the performance of designs under deviation, systems are often engineered by evaluating their performance exclusively at nominal conditions. Robustness is sometimes evaluated a posteriori throug ...

2022

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

Jürg Alexander Schiffmann, Markus Diehl, Christoph Schreiber

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

Real-time optimization of load sharing for gas compressors in the presence of uncertainty

Dominique Bonvin, Alejandro Gabriel Marchetti, Timm Faulwasser, Predrag Milosavljevic

This paper investigates the problem of load-sharing optimization of gas compressors in the presence of uncertainty. The objective is to operate a set of compressor units in an energy-efficient way, while at the same time meeting a varying load demand. The ...

ELSEVIER SCI LTD2020

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

Design of Compact Bearingless Disc Drive Systems

Yves Perriard, Douglas Martins Araujo, Juan Patricio Tomás Peralta Fierro

Inflating costs and emerging applications are spawning interests toward smaller and faster electric drives. The challenges of miniaturization make magnetic bearings more appealing, as they provide intrinsic high-speed capability and need virtually zero-mai ...

2020

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

Impact of large tip clearance ratios on the performance of a centrifugal compressor

Jürg Alexander Schiffmann, Markus Diehl

Ultra-compact and fast spinning turbomachinery is a key technology to increase performance of domestic heating applications and to address decentralization of power and heat as a consequence of the rise of renewable energy sources. Recently, a heat pump us ...

2019

Mitigation of tip leakage induced phenomena in a low Reynolds number centrifugal compressor via blade loading distribution

Markus Diehl

Reduced-scale refrigeration compressors supported on gas-lubricated bearings have been identified as a key technology for domestic heat pump applications, in order to improve both the system efficiency and the reliability. Unfortunately, reduced-scale mach ...

EPFL2019

Metal hydride compressor control device and method

Andreas Züttel, Noris André Gallandat

The present relates to a Metal hydride compressor control method for generating a variable output pressure P_desired_outPut, comprising a first step of inflowing gaseous hydrogen into a metal hydride compartment at a constant temperature and then stopping ...

2019

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

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

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, 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

Real-Time Optimization of Interconnected Systems via Modifier Adaptation, with Application to Gas-Compressor Stations

Predrag Milosavljevic

The process industries are characterized by a large number of continuously operating plants, for which optimal operation is of economic and ecological importance. Many industrial systems can be regarded as an arrangement of several subsystems, where outp ...

EPFL2018

Potential and Challenges of ORC driven Heat Pumps Based on Gas Bearing Supported Turbomachinery

Violette Mounier

Electrically Driven Heat Pumps (EDHPs) have been identified as a key technology to reduce the energy consumption in the domestic space heating sector. However, since EDHPs require electrical power, they face issues related to network overload at peak-time, ...

EPFL2018

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

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

Testing and modelling of a novel oil-free co-rotating scroll machine with water injection

Jürg Alexander Schiffmann, Luis Carlos Mendoza Toledo

Efficient compressed air energy storage requires reversible isothermal compression and expansion devices. The isothermal compression and expansion processes can either be approached by several stages with intercooling or by the more convenient injection of ...

Elsevier2017