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Small, High-Speed, Oil-Free Radial Turbo-compressors for Cooling Applications: Refrigerant Selection
Publications associées (54)
Scale limitations of gas bearing supported turbocompressors for vapor compression cycles
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 ...
2020Multi-objective optimization and exergoeconomic analysis of a continuous solar-driven system with PCM for power, cooling and freshwater production
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 ...
PERGAMON-ELSEVIER SCIENCE LTD2020Real-time optimization of load sharing for gas compressors in the presence of uncertainty
Dominique Bonvin, Timm Faulwasser, Alejandro Gabriel Marchetti, 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 LTD2020The 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 ...
2020Experimental Performance of Completely Passive Single and Recirculating Loop Thermosyphon Cooling Systems using Low GWP R1234ze and R1234yf
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 ...
IEEE2019Enhancing 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 Press2019Water-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 ...
2019Impact 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 ...
2019Mitigation of tip leakage induced phenomena in a low Reynolds number centrifugal compressor via blade loading distribution
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 ...
EPFL2019Thin Gas Film Isothermal Condensation in Aerodynamic Bearings
Jürg Alexander Schiffmann, Eliott Philippe Guenat
High-speed small-scale turbomachinery for waste heat recovery and vapor compression cycles is typically supported on gas-lubricated bearings operating close to the saturation conditions of the lubricant. Under particular conditions, the gas film might loca ...
2019