关键词: 逆布雷顿循环, 单螺杆膨胀机, 热力学过程, 数学模拟, 焓, 回热器, 绝热效率, 性能系数

Abstract: Expansion refrigeration can obtain relatively larger temperature drop, and it had the potential of utilization on industrial energy saving, such as cryogenics air separation, light hydrocarbon recovery, expansion valve replacement and mine cooling, etc. At present, lots of large-scale gas expansion refrigeration systems have been applied in many industrial fields. In many actual industrial processes, there were tremendous demands for small-scale gas expansion refrigeration units. However, those systems didn't realize commercial application due to technical and economic bottleneck. So research and development small-scale reverse Brayton cycle refrigeration system was very important to energy conservation and emission reduction for our country. In this paper, a typical process of reverse Brayton cycle refrigeration system was presented and the thermodynamic model was established, the influence factors of internal heat exchanger and the adiabatic efficiency of expanders were analyzed. From the simulation result, it was concluded that internal heat exchanger couldn't improve the coefficient of performance for entire system, but could decrease the outlet temperature of expander efficiently. With the increase of reheat temperature difference, the effect of reheat reduced. Those works can provide the theoretic basis to study on small-scale reverse Brayton cycle refrigeration system.

Key words: reverse Brayton cycle, single screw expander, thermodynamics process, mathematical modeling, enthalpy, internal heat exchanger, adiabatic efficiency, coefficient of performance