Ecological Optimization For A Hybrid System Integrating A Phosphoric Acid Fuel Cell With An Absorption Refrigerator

On the basis of considering all kinds of irreversible factors during the working period of the phosphoric acid fuel cell,the mathematical model of the phosphoric acid fuel cell is established,and then the model is analyzed and optimized viewed from the electrochemistry and thermodynamics,we also studied the effects of working parameters on the performance of the fuel cell,including temperature,pressure,mole fraction of phosphate electrolyte,etc.In order to make use of the waste heat generated by the phosphoric acid fuel cell effectively,the mathematical model of a hybrid system composed of a phosphoric acid fuel cell and an absorption refrigerator was established,the absorption refrigerator was driven by the waste heat generated by the phosphoric acid fuel cell.The results showed that the maximum output power and output efficiency of the hybrid system were increased by 3.41% and 4.04%,and we obtained the best operating range of the output power is < < 8)(6,and the optimal operation interval of the output efficiency is < < 8)(6.Based on the model of the hybrid system,we analyzed all kinds of irreversible factors,and deduced the formula of entropy production rate of the hybrid system.And the hybrid system was optimized by using the principle of ecological optimization.Based on the above research,some conclusions are obtained.The main contents of this paper are as follows:In Chapter 1,the research background and development history of fuel cell and absorption refrigerator are introduced briefly.The second chapter establishes an typical model of phosphoric acid fuel cell.By means of the method of thermodynamics and electrochemical analysis,research the effects caused by three kinds of overvoltage on the performance of the phosphoric acid fuel cell,determine the calculation formulas of the main parameters;through the method of theoretical analysis and numerical simulation study the effect coursed by the main parameters,such as temperature,pressure,mole fraction of phosphoric acid,and obtained the optimization range of working parameters of the fuel cell.The third chapter established a theoretical model of a hybrid system that composed of an absorption refrigerator,a PAFC,and a regenerator,which is working in a stable state,several irreversible losses,electrochemical reaction,mass transfer and heat dissipation between the fuel cell and the refrigerator,heat leak into the environment and so on,are take into account.In the research,by means of theoretical analysis and numerical calculation,the effects caused by temperature,pressure,irreversible influence coefficient,cooling temperature and environment temperature on the performance of the hybrid system are studied,and the optimal intervals of the working parameters are obtained.In the fourth chapter,based on the model of the hybrid system established in the third chapter,some irreversible factors in hybrid systems are analyzed,and the calculation formula of entropy production rate of hybrid system is obtained.Thermodynamic optimization of the hybrid system of a phosphoric acid fuel cell and an absorption refrigerator was carried out by using the principle of ecological optimization.The relationship between the performance of entropy and the performance of output power and efficiency is take into comprehensive consideration.Based on the method of numerical analysis,and the objective function is the ecological criterion function and the ecological performance coefficient,the optimal intervals of working parameters is obtained.The last chapter summarizes the main contents and conclusions of this paper,analyses the inadequacies and innovations of this paper,and puts forward the ideas and prospects for the future research.