TY  - JOUR
A1  - Schwager, Christian
A1  - Flesch, Robert
A1  - Schwarzbözl, Peter
A1  - Herrmann, Ulf
A1  - Teixeira Boura, Cristiano José
T1  - Advanced two phase flow model for transient molten salt receiver system simulation
JF  - Solar Energy
N2  - In order to realistically predict and optimize the actual performance of a concentrating solar power (CSP) plant sophisticated simulation models and methods are required. This paper presents a detailed dynamic simulation model for a Molten Salt Solar Tower (MST) system, which is capable of simulating transient operation including detailed startup and shutdown procedures including drainage and refill. For appropriate representation of the transient behavior of the receiver as well as replication of local bulk and surface temperatures a discretized receiver model based on a novel homogeneous two-phase (2P) flow modelling approach is implemented in Modelica Dymola®. This allows for reasonable representation of the very different hydraulic and thermal properties of molten salt versus air as well as the transition between both. This dynamic 2P receiver model is embedded in a comprehensive one-dimensional model of a commercial scale MST system and coupled with a transient receiver flux density distribution from raytracing based heliostat field simulation. This enables for detailed process prediction with reasonable computational effort, while providing data such as local salt film and wall temperatures, realistic control behavior as well as net performance of the overall system. Besides a model description, this paper presents some results of a validation as well as the simulation of a complete startup procedure. Finally, a study on numerical simulation performance and grid dependencies is presented and discussed.
KW  - Molten salt solar tower
KW  - Molten salt receiver system
KW  - Dynamic simulation
KW  - Two-phase modelling
KW  - Transient flux distribution
Y1  - 2022
U6  - https://doi.org/10.1016/j.solener.2021.12.065
SN  - 0038-092X (print)
SN  - 1471-1257 (online)
VL  - 232
SP  - 362
EP  - 375
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Mikucki, Jill Ann
A1  - Schuler, C. G.
A1  - Digel, Ilya
A1  - Kowalski, Julia
A1  - Tuttle, M. J.
A1  - Chua, Michelle
A1  - Davis, R.
A1  - Purcell, Alicia
A1  - Ghosh, D.
A1  - Francke, G.
A1  - Feldmann, M.
A1  - Espe, C.
A1  - Heinen, Dirk
A1  - Dachwald, Bernd
A1  - Clemens, Joachim
A1  - Lyons, W. B.
A1  - Tulaczyk, S.
T1  - Field-Based planetary protection operations for melt probes: validation of clean access into the blood falls, antarctica, englacial ecosystem
JF  - Astrobiology
N2  - Subglacial environments on Earth offer important analogs to Ocean World targets in our solar system. These unique microbial ecosystems remain understudied due to the challenges of access through thick glacial ice (tens to hundreds of meters). Additionally, sub-ice collections must be conducted in a clean manner to ensure sample integrity for downstream microbiological and geochemical analyses. We describe the field-based cleaning of a melt probe that was used to collect brine samples from within a glacier conduit at Blood Falls, Antarctica, for geomicrobiological studies. We used a thermoelectric melting probe called the IceMole that was designed to be minimally invasive in that the logistical requirements in support of drilling operations were small and the probe could be cleaned, even in a remote field setting, so as to minimize potential contamination. In our study, the exterior bioburden on the IceMole was reduced to levels measured in most clean rooms, and below that of the ice surrounding our sampling target. Potential microbial contaminants were identified during the cleaning process; however, very few were detected in the final englacial sample collected with the IceMole and were present in extremely low abundances (∼0.063% of 16S rRNA gene amplicon sequences). This cleaning protocol can help minimize contamination when working in remote field locations, support microbiological sampling of terrestrial subglacial environments using melting probes, and help inform planetary protection challenges for Ocean World analog mission concepts.
Y1  - 2023
U6  - https://doi.org/10.1089/ast.2021.0102
SN  - 1557-8070 (online)
SN  - 153-1074 (print)
VL  - 23
IS  - 11
SP  - 1165
EP  - 1178
PB  - Liebert
CY  - New York, NY
ER  -