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Beijing, China

Zhang Q.,CAS Institute of Electrical Engineering | Li X.,CAS Institute of Electrical Engineering | Wang Z.,CAS Institute of Electrical Engineering | Zhang J.,China R and nter | And 2 more authors.

Molten salt receivers play an important role in converting solar energy to thermal energy in concentrating solar power plants. This paper describes a dynamic mathematical model of the molten salt cavity receiver that couples the conduction, convection and radiation heat transfer processes in the receiver. The temperature dependence of the material properties is also considered. The radiosity method is used to calculate the radiation heat transfer inside the cavity. The outlet temperature of the receiver is calculated for 11 sets of transient working conditions. The simulation results compare well with experimental data, thus the model can be further used in system simulations of entire power plants. © 2015 Elsevier Ltd. All rights reserved. Source

Tong C.,Tsinghua University | Perez C.C.,Tsinghua University | Chen J.,Tsinghua University | Marcos J.-C.V.,China R and nter | And 2 more authors.
Energy Procedia

Absorbing CO2 with amine solutions is one of the most promising methods of CCS and has been widely applied. In order to improve efficiency and reduce costs, new solvents need to be selected. In this work, two amine solvents, N,N-dimethylethanolamine(DMEA) and Triethylene diamine (TEDA), have been characterized, with the use of gasliquid reactor for CO2 solubility and kinetic rate measurements. Solubility of CO2 has been measured for amine concentrations of 1.0, 2.5 and 4.0 mol/L at temperatures of 313.2K, 343.2K, 373.2K, and 393.2K while partial pressure of CO2 varies from 1 to 300kPa. The e-NRTL model has been used for these amine-water-CO2 systems in order to calculate CO2 solubility. Meanwhile the thermo-regulated constant interfacial area Lewis-type cell was also operated to obtain absorption kinetic data for CO2 absorption in 0.5M and 1.0M amine solutions. Source

Faille D.,Electricite de France | Liu S.,China R and nter | Wang Z.,Chinese Academy of Sciences | Yang Z.,Chinese Academy of Sciences
Energy Procedia

This paper deals with the development of a control design model for a 1MW Solar Tower equipped with a heat storage facility. This model is precise enough to achieve a good prediction of the responses but is also simple enough to avoid computational burden. The paper presents the assumptions and equations used for the different components of the plant. The behavior of the model developed in Matlab/Simulink™ is qualitatively validated by closed loop simulations. The control used for these simulations is also given. It consists of two levels, the upper level being an automaton whose outputs are the set points of the lower level controllers. © 2013 D. Faille. Source

Shi Y.-L.,Tongji University | Yang L.,China R and nter | Zhang C.-L.,Shanghai JiaoTong University
Energy and Buildings

The small air cooled chillers that serve an apartment building or residential villa often have the outdoor condensing units installed within a confined space. The installation distance between chiller and wall or between two chillers has significant impact on the chiller performance. In this study, three CFD (Computational Fluid Dynamics) approaches to condensing unit air management modeling are proposed and compared with each other first. The predicted air flow rates are compared to the test data as well. The comparison shows that the CFD approach with fan boundary definition is the most cost-effective, easy to be implemented, and accurate. Together with the chiller system modeling, a parametric study is further conducted to investigate the effect of the wall-chiller distance and the chiller-chiller distance on the chiller performance. © 2011 Elsevier B.V. All rights reserved. Source

Li H.,Tsinghua University | Le Moullec Y.,Electricite de France | Lu J.,China R and nter | Chen J.,Tsinghua University | And 3 more authors.
Fluid Phase Equilibria

An accurate thermodynamic model is the primary element needed for the process simulation and optimization for CO2 absorption in aqueous amine solutions. In this work, the thermodynamic model was built in Aspen Plus, using the electrolyte nonrandom two-liquid (ENRTL) activity coefficient model to represent vapor pressure and heat capacity data, simultaneously, for amine, vapor-liquid equilibrium (VLE), excess enthalpy (HE), and pKa data for amine/H2O, and CO2 solubility data for amine/CO2/H2O. The cyclic diamine 1-methylpiperazine (1MPZ) is a promising amine for CO2 capture. CO2 solubility was measured for 1MPZ aqueous solutions at three concentrations - 10wt%, 30wt%, and 40wt% and four temperatures - 313.15K, 343.15K, 373.15K, and 393.15K. The excess enthalpy for 1MPZ+H2O was obtained by the Setaram C80 calorimeter at 303.15K and 323.15K, within a whole mole-fraction range. The interaction parameters of nonrandom two-liquid model (NRTL) and ENRTL, along with the standard state properties of amine ions - protonated 1MPZ (1MPZH+, 1MPZH2+), 1MPZ carbamate (1MPZCOO-), and protonated 1MPZ carbamate (H1MPZCOO) - were regressed from data obtained from this work as well as literature, which agreed with the model calculation. © 2015. Source

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