Chapter 3 - Fluid Dynamics

Many different experiments had shown, that ice-slurry behaves as a Newtonian fluid at low ice-concentrations, and non-Newtonian fluid at higher ice-concentrations. The most widley used rheological model is the Bingham fluid model

Chapter 3 - Fluid Dynamics

Many different experiments had shown, that ice-slurry behaves as a Newtonian fluid at low ice-concentrations, and non-Newtonian fluid at higher ice-concentrations. The most widley used rheological model is the Bingham fluid model

Data for: Dataset concerning the hourly conversion factors for the cumulative energy demand and its non-renewable part, and hourly GHG emission factors of the Swiss electricity mix during a one-year period (2016 and 2017)

The provided data are the hourly CO2-eq emission factors, and the hourly conversion factors for the cumulative energy demand and its non-renewable part for the Swiss electricity mix over one year (2016 and 2017). These data have been assessed on the base of an inventory of the technology used for electricity generation and an attributional life-cycle approach according to the methodology presented in [1]. Compared with [2], electricity imports from Italy to Switzerland are not neglected anymore, and lead to more accurate output data. The presented data are necessary for life cycle assessment of all processes and products using electricity in Switzerland. They serve also as a sustainable benchmark when implementing renewable energy systems and energy storage, as well as for the quantitative follow-up of the decarbonization process of the grid electricity at the national level

Analysis Of An Active Magnetic Regenerator Made Of Gadolinium Wires

During the last century, the MagnetoCaloric Effect (MCE) has been widely used for realizing extremely low temperatures. However, it is only in the last three decades that some of the efforts to develop a benign and cutting-edge technology for realizing the MCE at temperatures around room temperature have been realized. The main component of magnetocaloric systems is the Active Magnetic Regenerator (AMR), but it is difficult to realize an optimum design for the AMR because of the poor mechanical properties of the MagnetoCaloric Materials (MCMs). In this study, an AMR configuration comprising a stack of gadolinium wires is investigated. A 1D physical model and a computer simulation program that can be used for studying the system are discussed in detail. The pressure drop, refrigeration capacity, and Coefficient Of Performance (COP) are numerically evaluated. Numerous simulation results obtained by using water as the working fluid for different regenerator geometries are discussed and optimal solutions are presented. These results are compared with those obtained for a configuration containing a bed of particles through which the working fluid flows

Experimental validation of a coupled magneto-thermal model for a flat-parallel-plate active magnetic regenerator

In this study, a flat-parallel-plate active magnetic regenerator made of gadolinium is investigated. The coupling of a one-dimensional thermal model with a two-dimensional magnetic model is presented. The thermal model takes into consideration the magnetocaloric effect as a source term and the energy conservation between a solid and a fluid. The magnetic model considers the space distribution of the internal magnetic field strength, and thus it includes the demagnetization effect. Measurements on an experimental magnetic refrigeration test device are performed using distilled water as the working fluid. At cyclic steady states, the temperatures of the fluid on both sides of the regenerator are calculated numerically and compared with the measurement results. The inability to provide a constant internal magnetic field during the heat transfer process with a permanent magnet is demonstrated. A reasonable agreement between simulations and experiments confirms the validity of the proposed model. (C) 2013 Elsevier Ltd. All rights reserved

Numerical analysis of a reciprocating active magnetic regenerator made of gadolinium wires

During the last century, the MagnetoCaloric Effect (MCE) has been widely used for realizing extremely low temperatures. However, it is only in the last three decades that some of the efforts to develop a benign and cutting-edge technology for realizing the MCE at temperatures around room temperature have been realized. The main component of magnetocaloric systems is the Active Magnetic Regenerator (AMR), but it is difficult to realize an optimum design for the AMR because of the poor mechanical properties of the MagnetoCaloric Materials (MCMs). In this study, an AMR configuration comprising a stack of gadolinium wires is investigated. A 1D physical model and a computer simulation program that can be used for studying the system are discussed in detail. The pressure drop, refrigeration capacity, Coefficient Of Performance (COP) and the exergy efficiency are numerically evaluated. Numerous simulation results obtained by using water as the working fluid for different regenerator geometries are discussed and optimal solutions are presented. These results are compared with those obtained for a configuration containing a bed of particles through which the working fluid flows. (C) 2011 Elsevier Ltd. All rights reserved

Data for: Dataset concerning the hourly conversion factors for the cumulative energy demand and its non-renewable part, and hourly GHG emission factors of the Swiss electricity mix during a one-year period (2016 and 2017)

The provided data are the hourly CO2-eq emission factors, and the hourly conversion factors for the cumulative energy demand and its non-renewable part for the Swiss electricity mix over one year (2016 and 2017). These data have been assessed on the base of an inventory of the technology used for electricity generation and an attributional life-cycle approach according to the methodology presented in [1]. Compared with [2], electricity imports from Italy to Switzerland are not neglected anymore, and lead to more accurate output data. The presented data are necessary for life cycle assessment of all processes and products using electricity in Switzerland. They serve also as a sustainable benchmark when implementing renewable energy systems and energy storage, as well as for the quantitative follow-up of the decarbonization process of the grid electricity at the national level

On the Necessity to Integrate Power Flexibility in Cooling Systems

Abstract Today, cooling systems are widely used, notably with the unprecedented growth of data centres and building space cooling. These thermodynamic systems are powered mainly with electricity, and their peak loads are generally associated with very high carbon footprints. At the same time, congestion of the grid due to high load or renewable power injection is becoming an issue for all actors involved with electricity (producers, providers, consumers, and prosumers). Actually, both the price and associated carbon footprint of electricity usually fluctuates along with the charge of the network. This paper discusses the integration of power flexibility (PF) in new and existing cooling systems to avoid a possible cold crunch in the near future. After defining PF, several cooling systems archetypes are presented. Three possible ways to integrate PF are explained: flexibility by thermal inertia and energy storage (thermal and electrochemical). While PF principally targets the reduction of stress on the electric grid, other benefits can also be achieved, e.g. mitigation of direct carbon emissions and decrease of costs related to operating the refrigeration system. We explain how better management of energy transits and possible imbalance in electricity networks can be achieved by thermal inertia. The choice of integrating thermal storage or electric battery is discussed, and both solutions are considered in a specific case study. The study aims at better management of power loads on electricity network caused by the cooling system and could be useful for anyone involved with grid management and/or refrigeration systems.</jats:p