Small-scale Refrigeration System Simulation And Irreversibility Analysis

Conserving-energy of buildings is an important policy during the tenth five-plan years, and conserving-energy of air-conditioners is an important part of the former. Household air-conditioning systems are air-conditioning devices in the widest use. Conserving-energy of household air-conditioning systems is important to nations, enterprises producing equipments and consumers. Employing the method of computer simulation to study household air-conditioning systems has advantages of saving experiment expense, shortening time of product development, decreasing cost, so it has been a means of system working performance research, component or device improvement and optimum, and device control system development.The paper reviewed the state of study on air-conditioning and refrigeration system simulation at home and abroad, presented simulation models of air-conditioning and refrigeration systems, made relevant simulation programs, used experimental results to verify the simulation models, and presented a method of air-conditioning system irreversibility analysis based on the simulation, Finally, presented pending further studied problems.Chapters and sections are arranged as followsThe first chapter reviewed the state of component and system simulation models of refrigeration systems in China and presented major contents studied in this paper.The second chapter developed the general model of CFCs and substitute refrigerant thermodynamic and transport properties based on the MH (Martin-Hou) state equation and made computational programs. To take refrigerant CFC12, HCFC2 and HFC134a for example, verifies the validation of the model. By comparing the operation performance of the different working substance heat pump, it indicates that operation performances of these heat pumps are rather similar. In the heat pump system, HCFC22 and HFC134a are excellent alternatives for CFC12.The third chapter employed a new method of taking pressure as step to simulate refrigerant flow characteristics in adiabatic capillary tubes, based on adiabatic capillary tube mathematic models. Refrigerant critical flux in capillary tubes is predicted by means of back-propagated method. It indicates that this method can savecomputational time, so it can be used in engineering.The fourth chapter to the seventh chapter selected and improved fully hermetic rotary compressor mathematic models, condenser and evaporator distributive parameter models, and refrigerant charge inventory models, consulted domestic excellent enterprise' s product and components, and made relevant simulation programs.The eighth chapter used above component models and simulation programs to simulate KFR-HI/LW air-conditioners made in some enterprise, and compared predictions and experimental results. It indicated that simulation methods and programs presented in this paper are feasible.The ninth chapter analysed irreversibility of each component based on air-conditioning simulation. It indicated that the reason why Exergy destroyed is caused is compressed ratio, superheated temperature and subcooled temperature.The tenth chapter presented valuable research topics in the field.