This book describes a numerical model developed for the power block of a Parabolic Trough type concentrating solar power plant. The entire book can be broken down into four main categories: 1. Theory of Concentrating Solar Power plants and relevant research. 2. Development of the design model and performance model 3. Integration of Numerical Model into Simulation Tool 4. Results and Discussion The book intends to present the concepts used to develop the thermodynamic model and understand the intrinsic behind it. With the help of descriptive figures and tables the theory behind the model and its working is explained. The results are compared with data from other institutes and papers for validation of the model.