Modeling and co-simulation of a parabolic trough solar plant for industrial process heat

• Published in: Applied energy Vol. 106; pp. 287 - 300
• Main Authors: Silva, R., Pérez, M., Fernández-Garcia, A.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.06.2013; Elsevier
• Subjects: Applied sciences; climate; Co-simulation; computer software; Energy; Exact sciences and technology; heat; mass flow; Modelica; Parabolic-trough collectors; Process heat; solar radiation; TISC; TRNSYS; Spain, Andalucia, Almeria; Parabolic-trough collectors; TISC; TRNSYS; Modelica; Co-simulation; Process heat; Simulation; Secondary sector; Modeling
• ISSN: 0306-2619; 1872-9118
• DOI: 10.1016/j.apenergy.2013.01.069

► A tri-dimensional dynamic complex model of a parabolic-trough collector is proposed. ► The collector model was validated with experimental data and agrees very well. ► An innovative co-simulation integration environment for PTC plants is developed. ► Co-simulations with complex dynamic and simplified stationary models were compared. ► Co-simulations for a reference solar industrial process heat scenario are presented. In the present paper a tri-dimensional non-linear dynamic thermohydraulic model of a parabolic trough collector was developed in the high-level acausal object-oriented language Modelica and coupled to a solar industrial process heat plant modeled in TRNSYS. The integration is performed in an innovative co-simulation environment based on the TLK interconnect software connector middleware. A discrete Monte Carlo ray-tracing model was developed in SolTrace to compute the solar radiation heterogeneous local concentration ratio in the parabolic trough collector absorber outer surface. The obtained results show that the efficiency predicted by the model agrees well with experimental data with a root mean square error of 1.2%. The dynamic performance was validated with experimental data from the Acurex solar field, located at the Plataforma Solar de Almeria, South-East Spain, and presents a good agreement. An optimization of the IST collector mass flow rate was performed based on the minimization of an energy loss cost function showing an optimal mass flow rate of 0.22kg/sm2. A parametric analysis showed the influence on collector efficiency of several design properties, such as the absorber emittance and absorptance. Different parabolic trough solar field model structures were compared showing that, from a thermal point of view, the one-dimensional model performs close to the bi-dimensional. Co-simulations conducted on a reference industrial process heat scenario on a South European climate show an annual solar fraction of 67% for a solar plant consisting on a solar field of 1000m2, with thermal energy storage, coupled to a continuous industrial thermal demand of 100kW.