Experimental And Numerical Study On Characteristics Of Combined Heating And Power Generation System Based On Solar Photovoltaic/Thermal And Proton Exchange Membrane Fuel Cells(PEMFC)

The distributed combined heating and power generation(DCHP)system is a total energy system,which is located in the enduser site and integrated the different equipment into a comprehensive system to provide simultaneously the user with the supply of hot water,heating and electricity based on the so-called principle of“temperature counterpart and cascade utilization”.As a new energy supply device,proton exchange membrane fuel cell(PEMFC)is currently the most promising low temperature fuel cell,it can be used as power plant and portable source with clean and efficient.As a green renewable energy resource,solar energy has been developed and applied to a wider areas,which has the advantages of abundant resources,cleanness,non-pollution and so on.But the meteorological conditiontions have great influence on the solar energy,leading to unreliable and discontinuous in the solar energy applications.The DCHP system for solar photovoltaic/thermal and PEMFC can utilize energy effectively and improve energy efficiency evidently.Therefore,the development and practical application of DCHP is of importance to relieve the energy crisis and reduce environment pollution in both theoretical study and engineering applications.The subsystem experiment devices for solar photovoltaic/thermal and PEMFC is designed in this paper.The DCHP system for experiment devices take full advantage of energy in solar photovoltaic/thermal with the principle of "temperature counterpart and cascade utilization”,which produce heat and power and improve the whole system energy efficiency evidently,the stability and continuity energy supply is provided by this DCHP system.The multi-softwares collaborative simulation platform of cogeneration system is constructed through Excel VBA technology based on the principle of computational fluid dynamics software Gambit/Fluent and Matlab/Simulink characteristics.The equipment structure and performance are optimized by Gambit/Fluent simulation with generating computational model grids and setting the single device physical parameters.Matlab/Simulink is used to analyze thermal equipment performance parameters,simulate dynamic and static characteristics for thermodynamic system,because Matlab/Simulink are integrated software packages to model,simulate and analyze dynamical system.As the data analysis software,Excel VBA can storage Gambit/Fluent numerical data and Matlab/Simulink simulation data,it also realize the data communication between Gambit/Fluent and Matlab/Simulink so as to achieve the purpose of multi-softwares collaborative simulation.The Meteorological workstation is set up to obtain local real-time solar energy meteorological parameters.The related polynomials are formed according to annual and daily variation of meteorological parameters which include radiation intensity,environmental temperature,humidity,dew point temperature and wind speed.The functional relationships between radiation intensity and ambient temperature,between the ambient humidity and dew point temperature,are studied by local meteorological data analysis.The total radiation intensity influence factor include latitude,longitude,altitude are studied according to the HOTTEL sunny radiation simulation model which reliability is verified by experimental data.The study of local solar meteorological parameters can provide accurate meteorological data for the simulation of solar photovoltaic/thermal and PEMFC cogeneration system.The numerical calculation models are structured according to the flow and heat transfer characteristics in natural convection solar collectors,the reliability of numerical calculation models are verified by natural convection solar collectors experiment platform.The influence factor of collector performance are numerical studied which include evacuated tube diameter,evacuated tube length,evacuated tube absorptivity and evacuated tube emissivity.Solar collectors equiped with guide plate are designed according to the experiment and simulation data to simulate guide plate reasonable length,position and thickness.Finally,the solar collector which equipped with guide plate,high absorptivity and low emissivity is suitable for solar photovoltaic/thermal and PEMFC cogeneration system.The numerical calculation models which include horizontal double collectors and U-type tube collectors are formed according to the flow and heat transfer characteristics in forced convection solar collectors.The influence factor of horizontal double collectors performance are numerical studied which include inlet velocity and installation angles with collector thermal efficiency and entransy increment.The influence factor of U-type tube collectors performance are numerical studied which include U-type tube diameters and U-type tube thickness.Finally,the horizontal double solar collector is suitable for the solar photovoltaic/thermal and PEMFC combined heat and power system.The temperature field and velocity field which include single heated collectors,double heated collectors,guide plate collectors,horizontal double collectors and U-type tube collectors are visual analyzed with Tecplot software.The optimum synergy zone of temperature field and velocity field in solar collectors is determined with field synergy principle.The performance parameters of experiment device which include solar photovoltaic panel,solar controller,battery and PEMFC simulator are studied according to subsystem experiment for solar photovoltaic/thermal and PEMFC.The improvement system for solar energy/wind energy and PEMFC is formed with experiment data.The performance parameters of experiment equipment which include horizontal double collector,water storage tank,air source heat pump and plate solar collectors are studied in this paper with plate solar collector experiment platform and hot water system for horizontal double collector coupling air source heat pump.The improvement system for solar heating/air source heat pump and PEMFC is formed with experiment data.The dynamic simulation model for PEMFC stack/plate heat exchanger and the static simulation model for PEMFC stack output voltage are set up with the simulation platform include Excel VBA and Matlab/Simulink softwares.The influence factor include stack current,stack temperature,fuel pressure are studied on stack output voltage.The dynamic variation rule with running time are studied on stack temperature,thermal power of cycle cooling water,cooling water flow rate.The PEMFC stack/thermal utilization feasibility is verified because the operational parameters of solar cooling water for PEMFC stack/plate heat exchanger are determined.