Shiraz solar thermal power plant is designed for 250 kW power supply during available sun radiation. It is decided to promote the field of collectors by installing a large parabolic collector and combining the system with a 500 kW hybrid boiler. For the new integrated configuration, thermodynamic analysis is required for engineering design and evaluating thermal performance. For the new system, transient simulation is performed under different working conditions. In the plant, each component is simulated transiently, by considering initial condition and capacity rate of the component as well as all the connecting pipes and instruments. Results of the simulation for thermal performance are compared with field experimental measurements for several periods. Taking into account the thermodynamic concepts and the results of numerical and experimental analysis, the best operation strategies are selected for optimum performance and control philosophy based on the new integrated collector. (C) 2012 Elsevier Ltd. All rights reserved.