21 research outputs found
Ausbau des DLR-Standorts Jülich: Aktionsraum für CSP-Versuchsanlagen im Pilotmaßstab
Posterbeitrag zum aktuellen Stand des Ausbaus des DLR-Standorts Jülich. Es werden das Ausbaukonzept und einige konkrete Maßnahmen beschrieben
Dynamic Simulation of a solar tower system with open volumetic receiver - a review on the vICERP project
The paper presents an overview on the modeling and simulation activities of the virtual institute for central
receiver power plants (vICERP). Within a three years launch period models and tools for dynamic simulation
of central receiver power plants have been developed by the five research institutes involved. The models are
based on the Modelica modeling language. Today, models for the heliostat field, the receiver, the air cycle,
the thermal storage, and the water-steam cycle are available within the consortium. As a first application, the
Solar Tower Jülich technology was used as a reference. Models are validated with real operational data from
the Solar Tower Jülich
Dynamic simulation tool for a performance evaluation and sensitivity study of a parabolic trough collector system with concrete thermal energy storage
Plant developers of parabolic trough collector (PTC) systems for industrial steam generation face various challenges. Some of the main challenges are availability of land, buildings in the vicinity of the plant that cast shadows on the collectors as well as land restrictions. The typical north-south collector axis alignment in many cases may not be possible due to limits of available ground. These were challenges that were faced in the planning phase for installing a PTC plant on the premises of the KEAN Soft Drinks Ltd factory in Limassol, Cyprus. As these issues cannot be avoided they must be accounted for by the plant developer, especially when a performance guarantee is given. This work presents, amongst other things, factors that should be analysed in order to predict the energy yield in the planning phase as best as possible by using a simulation model. In the sensitivity study presented in this paper, several effects on the energy yield were investigated theoretically. These effects include: Tracking inaccuracy, non-parallel collector row axis orientations as well as north-south vs. east-west collector alignment. A dynamic simulation model developed by the Solar-Institut Jülich (SIJ) [1] was further developed and used for the analysis. The simulation model features a deviation between the measured and simulated oil temperature at the collector outlet of only 1.5 K (rms). The findings are presented in this paper and give an insight into the effectiveness of mid-sized PTC systems for the industry sector
Operational experience and behaviour of a parabolic trough collector system with concrete thermal energy storage for process steam generation in Cyprus
As part of the transnational research project EDITOR, a parabolic trough collector system (PTC) with concrete thermal energy storage (C-TES) was installed and commissioned in Limassol, Cyprus. The system is located on the premises of the beverage manufacturer KEAN Soft Drinks Ltd. and its function is to supply process steam for the factory’s pasteurisation process [1]. Depending on the factory’s seasonally varying capacity for beverage production, the solar system delivers between 5 and 25 % of the total steam demand. In combination with the C-TES, the solar plant can supply process steam on demand before sunrise or after sunset. Furthermore, the C-TES compensates the PTC during the day in fluctuating weather conditions. The parabolic trough collector as well as the control and oil handling unit is designed and manufactured by Protarget AG, Germany. The C-TES is designed and produced by CADE Soluciones de Ingeniería, S.L., Spain. In the focus of this paper is the description of the operational experience with the PTC, C-TES and boiler during the commissioning and operation phase. Additionally, innovative optimisation measures are presented
Advanced two phase flow model for transient molten salt receiver system simulation
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
Optimized control of hot-gas cycle for solar thermal power plants
In this paper, the overall modeling approach for an
optimized control of a hot-gas cycle with its different
components for solar thermal power plants is pointed
out.
For control purposes a linear model-based controller
(MPC) was implemented in Modelica based on an
external state-of-the-art QP solver linked to the
Modelica model
Model predictive assistance for operational decision making in molten salt receiver systems
Despite the challenges of pioneering molten salt towers (MST), it remains the leading technology in central receiver power plants today, thanks to cost effective storage integration and high cost reduction potential. The limited controllability in volatile solar conditions can cause significant losses, which are difficult to estimate without comprehensive modeling [1]. This paper presents a Methodology to generate predictions of the dynamic behavior of the receiver system as part of an operating assistance system (OAS). Based on this, it delivers proposals if and when to drain and refill the receiver during a cloudy period in order maximize the net yield and quantifies the amount of net electricity gained by this. After prior analysis with a detailed dynamic two-phase model of the entire receiver system, two different reduced modeling approaches where developed and implemented in the OAS. A tailored decision algorithm utilizes both models to deliver the desired predictions efficiently and with appropriate accuracy
AIR-SAND HEAT EXCHANGER: MATERIALS AND FLOW PROPERTIES
In this paper, detailed analyses of some bulk materials and their flow properties related with the operation
with porous heat exchanger wall types are presented.
A focus is on granular media and their properties. Investigations with respect to attrition and abrasion have
been performed to identify the most suitable granular product in combination with different wall materials.
Tested products are alumina grinding balls, sintered bauxite, fused silica and silicon carbide on the ceramic
side, quartz sand and flints, basalt and normal corundum on the natural products side