TY  - JOUR
A1  - Alebouyeh Samami, Behzad
A1  - Pieper, Martin
A1  - Breitbach, Gerd
A1  - Hodapp, Josef
T1  - Heat production in the windings of the stators of electric machines under stationary condition
JF  - Heat and mass transfer
N2  - In electric machines due to high currents and resistive losses (joule heating) heat is produced. To avoid damages by overheating the design of effective cooling systems is required. Therefore the knowledge of heat sources and heat transfer processes is necessary. The purpose of this paper is to illustrate a good and effective calculation method for the temperature analysis based on homogenization techniques. These methods have been applied for the stator windings in a slot of an electric machine consisting of copper wires and resin. The key quantity here is an effective thermal conductivity, which characterizes the heterogeneous wire resin-arrangement inside the stator slot. To illustrate the applicability of the method, the analysis of a simplified, homogenized model is compared with the detailed analysis of temperature behavior inside a slot of an electric machine according to the heat generation. We considered here only the stationary situation. The achieved numerical results are accurate and show that the applied homogenization technique works in practice. Finally the results of simulations for the two cases, the original model of the slot and the homogenized model chosen for the slot (unit cell), are compared to experimental results.
Y1  - 2014
U6  - http://dx.doi.org/10.1007/s00231-014-1371-8
SN  - 0947-7411 (Print) ; 1432-1181 (E-Journal)
VL  - 50
SP  - 1707
EP  - 1716
PB  - Springer
CY  - Heidelberg
ER  - 
TY  - JOUR
A1  - Rau, Christoph
A1  - Alexopoulos, Spiros
A1  - Breitbach, Gerd
A1  - Hoffschmidt, Bernhard
A1  - Latzke, Markus
A1  - Sattler, Johannes, Christoph
T1  - Transient simulation of a solar-hybrid tower power plant with open volumetric receiver at the location Barstow
JF  - Energy procedia : proceedings of the SolarPACES 2013 International Conference
N2  - In this work the transient simulations of four hybrid solar tower power plant concepts with open-volumetric receiver technology for a location in Barstow-Daggett, USA, are presented. The open-volumetric receiver uses ambient air as heat transfer fluid and the hybridization is realized with a gas turbine. The Rankine cycle is heated by solar-heated air and/or by the gas turbine's flue gases. The plant can be operated in solar-only, hybrid parallel or combined cycle-only mode as well as in any intermediate load levels where the solar portion can vary between 0 to 100%.

The simulated plant is based on the configuration of a solar-hybrid power tower project, which is in planning for a site in Northern Algeria. The meteorological data for Barstow-Daggett was taken from the software meteonorm. The solar power tower simulation tool has been developed in the simulation environment MATLAB/Simulink and is validated.
Y1  - 2014
U6  - http://dx.doi.org/10.1016/j.egypro.2014.03.157
SN  - 1876-6102
VL  - 49
SP  - 1481
EP  - 1490
PB  - Elsevier
CY  - Amsterdam
ER  -