Application Research On Waste Heat Power Generation System

With the constraints of energy, the interest in low-quality heat recovery has grown dramatically in the past decades. Several new solutions have been proposed to generate electricity from low-quality heat sources, such as solar thermal power, biological waste heat and engine exhaust gases. The Organic Rankine Cycle (ORC) is preferred because of the simplicity and the availability of its components. Most previous work about dynamics of ORC has been focused on the analysis of thermodynamic, which is not benefit for controlling. Based on the moving boundary, the dynamics model of evaporator and condenser are proposed on the view of control-oriented modeling in this paper. Due to the dynamic characteristics of turbine and pump are faster than heat exchanger, the static models are chosen for the simplicity. Above all, the dynamics model of ORC system is proposed. In the most cases, the ORC operates only in the neighborhood of a predetermined operating point, so that it is reasonable to linearize the model around the predetermined operating point.Generalized predictive control(GPC) algorithm plays an important role in the industrial processes, which obtains the optimal control law through the prediction model, rolling optimization and feedback correction. During the heat exchanging, the outlet temperature of organic working fluids at evaporator is a critical variable. According to the dynamics of evaporator, a proper control law based on the generalized predictive control(GPC) is proposed for maintaining the outlet temperature of organic working fluids. The ORC systems a multivariable coupling system and the multivariable generalized predictive control algorithm is adopted. They are simulated in the environment of MATLAB/Simulink, the results show the effectiveness of the proposed schemes.