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

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

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

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

Lowering and phase shifting of temperature profiles with phase change materials in Minergie (TM) houses

A PCM dephaser and storage module based on a melting/freezing model was built and implemented into the Dymola-Modelica software. This software offers thermal libraries with standard components as tubes, pumps, heat exchangers, etc. Main simulation results of interest include the phase shift (delay time) caused by cylinders filled with a PCM and positioned in the storage/dephasing device. Furthermore, an entire Minergie (TM) house was modelled by a rather simple (economic in terms of CPU time), but still very effective thermal model. This house is connected to a suitable ventilation system chosen from a list of six different types. Therefore, also by graphical means on an interface, it is possible to create a Minergie (TM) house with an integrated thermal temperature lowering/phase shifting and heat recovery device. Temperature differences between a Minergie (TM) house connected to a storage device and a house without such a device are studied. Such systems are planned to be mainly used for hybrid cooling of Swiss Minergie (TM) houses in summer time. In a multi-functional application, they could also be applied in winter for a heating support. Numerous simulation results are discussed and optimal solutions are presented. (C) 2010 Elsevier Ltd and IIR. All rights reserved

The fluid dynamics of ice slurry

A review of research work of fluid dynamics of fine-crystalline ice slurry is presented. Different rheological models which are applied are presented. Numerous models for the friction factor, obtained by empirical and semi-empirical approximation, are discussed. An overview of existing pressure drop experiments is given and problematic issues of respective measurements and experimental results are outlined. Because ice slurry is a two-phase fluid that is considered to be homogeneous, only in some cases work on stratified suspension flows is cited. Finally a variety of experimental results and some theoretical calculations of ice slurry flow patterns are shown