Research On An Optimal Design Of The Solar Cogeneration System Based On ORC

Watchhouse is an important military facility,which is built to safeguard national territorial security and to strike border crime.There are lots of watchhouses in our country,they are small and mostly locate in remote areas.Soldiers stationed in the watchhouse usually generate electricity by diesel generator.The demand of heating of Soldiers in cold regions is met by small-sized coal fired boiler.This kind of energy supply mode depends on external fuel transportation,which can lead high cost,unreliability,inefficiency and pollution to environment.It should be improved pressingly.This paper propose a solar cogeneration system based on Organic Rankine Cycle to meet the energy demand of watchhouse in frigid plateau region.The operating mode of the system is firstly collecting solar energy by tubular solar collector.Secondly generating electricity through the ORC by using the heat and transferring the surplus heat to heat network.Then the optimal design of the system is conducted.Moreover,the operating characteristic of the system is analyzed.First of all,the best fit working fluid R134 a is chosen by the examination of working fluids' security,environmental protection,dry-wet property and saturability.The working parameters' effect on the thermal performance of basic ORC is investigated on the basis of the First Law efficiency and Second Law efficiency.Three kinds of system scheme and related operation strategies are proposed.The final scheme is determined after comparison.Secondly,the mathematical model of the system is established,which is calculated by MATLAB programme.It can be employed to simulate the generating capacity of the system.A series of experiment is conducted to validate the accuracy of the model.Thirdly,the least annual cost is regarded as the objective function,design variables consist of solar collector area,heat storage water tank volume,heat exchange area of evaporator,heat exchange area of condenser,accumulator capacity and the activated pressure difference of generator,the optimal model of the solar cogeneration system is built with orthogonal optimization method.A case of a watchhouse in River TuoTuo,Qinghai Province is set to be an example to optimize the system.The result shows the converted electricity price is 2.3 Yuan per kilowatt hour,and it is free to supply heat.Finally,the hourly operation simulation during the whole year of the system of the case is conducted.The operation characteristic of the system is analyzed.The result shows that 94.56% electrical load is taken on by the system,5.44% electrical load is taken on by the diesel generator,100% heat load is taken on by the system.The solar cogeneration system based on ORC is reliable.The superiority of the system is evaluated from the aspect of economy,environmental protection property and reliability.