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Electricity production costs and overall net efficiency of the system are determining factors regarding the quality and cost effectiveness of a solar tower power plant. These factors are strongly dependent on the quality of heliostats, the receiver and the thermal storage concept. This work describes the optimization of load states of a storage system through applying internal process control strategies for the air circuit of the Solar Tower Jülich which works with open volumetric air receiver technology. A concept for optimal operation of the thermal storage system was formulated and developed. Storage concepts include both technical adjustments of the existing storage system as well as the control process of the thermal storage. For simulating the optimized operating strategy of the power plant systems all main power plant components were modeled in MATLAB ® /Simulink ® and interconnected to form a complete system. The focus of the simulation lies in optimizing the operating strategy of a discretized thermal energy storage model. [ABSTRACT FROM AUTHOR]

Abstract: 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. [Copyright &y& Elsevier]

We have previously shown that human-xenogeneic cross-circulation (HX-XC) can rehabilitate human lungs deemed unsuitable for transplant. We found that porcine antibodies and leukocytes infiltrate the human lung during HX-XC, raising concern that re-exposure to human blood may trigger hyperacute rejection. The purpose of our study is to evaluate the consequences of human blood re-exposure on a lung recovered with HX-XC. Donor lungs deemed unsuitable for transplant and autologous whole blood were procured. Lungs were perfused by an immunosuppressed swine host for 12 hrs. After removal from HX-XC, lungs were placed on EVLP with autologous human blood for 5 hrs. Physiologic data and biopsies were collected during HX-XC and EVLP. Tissue was stained with H&E; IHC was used to assess for apoptosis (TUNEL, caspase-3) and complement activation (C4d, membrane attack complex, MAC). During HX-XC, PaO 2 /FiO 2 and mean airway pressure (MAP) remained stable (mean 254±20 mmHg and 6.8± 0 cmH 2 O, respectively). Dynamic compliance improved from 23 to 52 mL/cmH 2 O. During blood re-exposure with EVLP, dynamic compliance and MAP remained stable. The structural integrity of the lung was maintained after re-exposure to human blood, without evidence of diffuse pulmonary edema. Though apoptosis was detected during HX-XC, these levels did not increase during blood re-exposure. Complement and MAC deposition were focally present after blood re-exposure. A human lung rescued with HX-XC and re-exposed to autologous blood maintained physiologic function, despite exposure to porcine antigen. These preliminary data suggest there may be minimal deleterious effect of re-exposure to human blood after xeno cross-circulation. Further studies are needed to confirm these findings. [ABSTRACT FROM AUTHOR]