Simulation Of Steady State Characteristics And Performance Study On Low-temperature Waste Heat Power Generation System Using Organic Rankine Cycle

Abstract:Domestic and foreign scholars in the study of low-temperature waste heat power generation ORC system mainly are in theoretical and experimental research. theoretical calculation is very unreliable due to low precision, and experimental studies have high cost and are difficult to optimize and other shortcomings. The using of computer simulation is a very good way to be able to effectively overcome theoretical calculations and experimental studies’ fault. This paper proposes the use of simulation methods to study other parameters and performance parameters’ influence of the different outside parameters on low-temperature waste heat power generation ORC system, and mainly is to do the following work:First, this article summarizes the research current situation on low-temperature waste heat ORC power generation system, and introduces the principle and composition structure, and compare and analysis the different effects of four common low boiling point dry working fluid. theoretical calculations show that R600a is better than the other three working fluids. Selecting R600a as refrigerant, a physical model on low-temperature waste heat ORC power generation system is designed and it selects the physical model’s expander, evaporator, condenser and refrigerant pump’s types.Secondly, studying the ORC physical model, the use of steady-state focus parameter method is to establish a mathematical model of its four main components, and it is given a specific algorithm for each component mathematical model. The working fluid pump and expander use focus parameter model, and the condenser and evaporator use focus parameter partition model. The reliability simulation result of evaporator complex mathematical models selects a literature data to carry out verification. simulation results show that the maximum relative error of the model’s calculated values and the datas from the literature is less than9%, so the model is reliable. Finally it uses mass, momentum and energy equations to solve the four coupling components, and this paper presents a specific algorithm for solving coupled flow. Being based on ORC system algorithms and the physical properties software "Refprop", the paper uses software "Visual fortran" to write the ORC system simulation program.Finally, using the above established mathematical model simulates the ORC system’s other internal parameters and performance parameters varying for different heat temperature, heat flow, the cooling water temperature, cooling water flow and mass flow rate. According to the simulation results, the paper quantitatively analysises and researchs source temperature, heat flow, the cooling water temperature, cooling water flow rate and mass flow rate of low-temperature waste heat ORC power generation system on evaporating temperature, condensing temperature, and the expansion ratio and the other internal parameters, and the output power, efficiency of the cycle and the other performance parameters’impacts. Simulation results provide an important datas reference for the design and optimization of ORC power system.