چكيده به لاتين
Abstract:
Using air as a refrigerant in cooling systems due to the low cooling effect of volume it may lead to a large compressor and high energy consumption in the production of cooling to be followed.Trains’air conditioning systems, typical, are considered as emitters of greenhouse gases. Air refrigerant air conditioners, even with a small amount of air leakage, are safe and can automatically recover the leaked air by a small compressor. The main objective of this research is modeling and optimization of the air conditioning system with air refrigerant for high speed trains, that in fact by showing how to influence performance from Brayton refrigeration cycle pressure ratio and efficiency of its mechanical and thermal components checked. Modeling was done in the train cabin, return air with fresh air coming in mixed cycle and after entering the compressor is compressed and then cooled by the cooling heat exchanger. Exhaust air from the previous stage enters the regenerator heat exchanger, with the aim of benefiting more from the return air, and after expansion by expander and Remove excess water droplets from the air by the removal of water entered the cabin space. changes in the specifications of each component of system is effective in the final performance and In this research after modeling the highest objective function, COP and Cooling energy produced per unit cost, are determined by optimizing the values of design variables.
By modeling and optimization bi-objective algorithm NSGA-II the best technical and economic values obtained in pressure ratio 2.11 and Equipment performance and efficiency coefficient obtained 85%-90% and coefficient of performance, COP, and Annual cost of cooling function 15.7 kWhours per dollar was calculated.
Analysis of the sensitivity of results to changes in ambient temperature and optimized cooling capacity have been explored that the results suggest COP decreased with increasing ambient temperature or increase the cooling capacity Also, the increase of COP is caused by reducing the ambient temperature or decrease the capacity of system.
Keywords: Reverse Brayton air cycle refrigeration, Train cooling system, Multi-objective optimization, and pressure ratio
