تبيين عملكرد ماشين حرارتي و سيكل تبريد با استفاده از مفهوم ترموديناميك زمان محدود

Thermal Machine and Refrigeration Cycle Performances on Base of Finite Time Concept

In this paper, the concept of finite time was applied in thermal machine and refrigeration cycle and irreversibility effects in consideration of transport phenomena were shown. The influence of time in these thermodynamic process leads to maximum coefficient of performance presented by Cruzon and Ahlborn instead of COP of a Carnot cycle for thermal machine. Calculation data shows that predicted thermal machine coefficient of performance by finite time concept is two times closer to real performance in comparison with Carnot cycle estimation. For refrigeration cycles, finite time analysis was applied and the suitable equations for prediction of COP irreversible processes by use of cycle temperatures were investigated and results were compared to real Stirling and Ericsson cycles. The calculation results show that at high temperature of heat sink, real coefficient of performance decreases and consequently, estimated coefficient of performance by finite time differ significantly with real coefficient of performance.