Performance Analysis Of Micro-combined Cooling,Heating And Power System Based On PEMFC

The global energy issues tend to be more crucial,therefore it is critically important for energy conservation and environmental protection.The Combined Cooling,Heating and Power(CCHP)system could achieve high efficiency energy cascade utilization.The fuel cells is suitable for applications in micro-CCHP system due to its advantages of clean,high efficient and low noise,thus has great application prospect in the future.Therefore,research on the micro-CCHP systems based on fuel cells will actively help solving energy problems and save non-renewable energy.This thesis mainly discusses the energy efficient micro-CCHP systems based on fuel cells.A proton exchange membrane fuel cell(PEMFC)based micro-CCHP system assisted by an energy storage equipment is proposed.A system model is established on the Simulink software platform.Then thermodynamic and economical evaluation models have been developed to estimate the system performance.It also studies the load forecasting of distributed energy system,and constructs high-accuracy load forecasting model based on BP artificial neural network method.Based on above,it simulates the system under operational conditions to study its dynamical performance,thermal performance and economic performance.And a PEMFC is fabricated and its performance is tested.In all,following conclusions are obtained: the average relative error between predicted value and real value for the load forecasting model based on BP artificial neural network is 3.96%,and the predicted progressing trend is completely consistent;the proposed micro-CCHP system assisted by the energy storage system can simultaneously meet the requirements of heating,cooling and electricity,the energy efficiency of the system in winter and summer is 81.24% and 69.95%,respectively,which is 10.33% and 9.62% higher than that of the single fuel cell system.It saves lots of fuel,and the refrigeration system COP is 0.7294.The proposed system has a great economical advantage;for the fuel cell performance test results,the output voltage decreases as the current density increases,and the intermediate cell voltage is slightly higher than the voltage across the two ends,and the thermal power will increase with the decrement of output electric power.The CCHP system proposed in this thesis is especially suitable for off-network operation because it does not need external power to ensure the energy requirements.This pilot research can be a reference for the construction and simulation of other similar systems.The constructed load forecasting model with high accuracy can be used for load forecasting of distributed energy systems,and is useful for guiding the CCHP system optimized operation.