Integration And Performance Simulation Study Of Combined Cooling Heating And Power System Based On Micro Turbine

As an important part of the project of"Demonstration and Key Technology Research of Natural Gas Transmission and High Efficiency Utilization"supported by Fund of Shanghai Science and Technology Development Committee(No. 023012003), performance simulation of combined cooling heating and power (CCHP) based on micro turbine and absorption chiller is researched. Using the simulation system, the design of control system of CCHP is researched, the control system on real CCHP system is realized, and the experiment is researched.CCHP based on micro turbine and absorption chiller is one late-model, cleanly, high efficiency integrated energy system with cascades utilization of energy, involves the simultaneous production of thermal and electric energy, is paid emphasis and researched. To reach high energy efficiency and control property, the dynamic performance of CCHP should be researched. At present, the main research contents are concentrated on the components'dynamic performance of CCHP or steady performance of CCHP. The performances and control study of CCHP based on micro turbine and absorption chiller is lacked.The integrated CCHP system of Shanghai jiaotong university software building is established provided a demonstration of CCHP with the prime mover of micro turbine and natural gas. The heating and cooling experiment result indicated: electric power, heating capacity, refrigeration capacity, electric efficiency and total energy utilization coefficient are about 57kW, 190.5kW, 233.4kW, 25.6%, over 0.8, the emission of NOX is under 9ppm, the noise is about 60dB at 10 meter. The CCHP system is high efficiency, environmental - protection, could reach the design requirements.Main research work done in the paper was listed as following:1. The project design of CCHPOrdering the request of project, CCHP system is composed by micro turbine, absorption chiller and low temperature absorption chiller. The performance of CCHP at design point is confirmed, the request of control system is analyzed. The necessarily of building dynamic performance model of CCHP, analyzing the dynamic performance and designing the PID controller is put forward.2. Modeling of heat exchanger used by volume inertia methodThe calculation process of the traditional differential models and calculation process of volume inertia models is compared, ordinary differential model of absorption chiller's components is suggested to avoid iterative calculation in traditional models, The thermal process of different heat exchanger in absorption chiller is analyzed; distributed-parameter model of single-phase heat exchanger, distributed-parameter model of two-phase heat exchanger and lumped-parameter model of two-phase heat exchanger is built by volume inertia modeling. The volume inertia model avoids derivation of partial differential equation, predigested the process of solution, and enhanced the stability of calculation. The steady and dynamic performance experiment of distributed-parameter model of single-phase heat exchanger is accomplished, the validity, veracity, distribution of parameters, infection of numbers of module in veracity, infection of simulation step-size in veracity, and infection of volume in the process of dynamic response is researched.3. Modeling of components used by volume inertia method and heat exchanger modelThe components of CCHP are divided based on modularized method. The dynamic performance simulation models of components, including: compressor, combustion chamber, gas-air heat exchanger, turbine, rotor, high pressure generation, low pressure generation, solution heat exchanger, condenser, evaporator, absorber, splitter, ejector, valve, pump, and pipe is built by modularize modeling and volume inertia method. Thermophysical properties of Li-Br solution, water, vapor, air, gas is programmed by fitting function, and subprogram library of thermophysical properties is compiled.4. Modeling and simulation research of dynamic performance of CCHP systemThe library of models of CCHP is built on the simulation software of Easy 5. The models of components are connected by parameters, the initial parameters and simulation step-size is configured, and the dynamic performance simulation system is established. The steady state simulation of CCHP in design point is accomplished, the simulation data is compared with the design parameters, the stability and veracity of simulation system is validated. The dynamic performance simulation of CCHP system is accomplished, the influence of disturbances including: request power of micro turbine, flow rate of cooling water and flow rate of cold water is analyzed. The result indicated: at the operating point for design, the relative error between the simulation and experiment is under 5 percents, electric power, refrigeration capacity, electric efficiency, total energy utilization coefficient are 57.2kW, 229.738kW, 25.6%, 0.809, matches the requirement of design. In the CCHP simulation system, the influence on total energy output and total energy utilization coefficient of CCHP is greater when the request power of micro turbine and the flow rate of cold water changed, is smaller when flow rate of cooling water changed.5. Design and realizing of control system of CCHP systemUsing the dynamic performance simulation system of CCHP system on the simulation software of Easy 5, the PID controller is designed to control the outlet temperature of cold water and the inlet temperature of cooling water. According the design parameters of PID controller, using PLC, IPC and configure software, the centralized automatic control system of two layers is established. The process of start or stop and load adjustment of CCHP system is automatic controlled by the control system. The result of control experiment indicated: the CCHP system with function of safe protection, real time monitoring and data record, could simple, convenient start and stop, could efficacious control the outlet temperature of cold water, the transition process is short, the CCHP system is stable operated.The integrated CCHP system of Shanghai jiaotong university software building is established provided a demonstration of CCHP with the prime mover of micro turbine and natural gas. The heating and cooling experiment result indicated: electric power, heating capacity, refrigeration capacity, electric efficiency and total energy utilization coefficient are 57kW, 229.738kW, 25.6%, 0.809, the emission of NOX is under 9ppm, the noise is about 60dB at 10 meter. The CCHP system is high efficiency, environmental - protection, could reach the design requirements.