Kayes Imrul, Ratul Raditun E, Abid Abyaz, Majmader Fawaz Bukht, Khan Yasin, Ehsan M Monjurul
Department of Mechanical and Production Engineering (MPE), Islamic University of Technology (IUT), Board Bazar, Gazipur-1704, Bangladesh.
Heliyon. 2024 May 23;10(11):e31655. doi: 10.1016/j.heliyon.2024.e31655. eCollection 2024 Jun 15.
The post-pandemic energy crisis and ever-increasing environmental degradation necessitate researchers to scrutinize refrigeration systems, major contributors to these issues, for minimal environmental impact and maximum performance. Thus, this study aims to comprehensively examine a triple cascade refrigeration system (TCRS) equipped with hydrocarbon refrigerants (1-butene/Heptane/m-Xylene). This system is specifically designed for ultra-low temperature applications, including vaccine storage, quick-freezing, frozen food preservation, cryogenic processes, and gas liquefaction. The investigation integrates conventional thermodynamic analysis with economic and environmental impact assessments, and finally multi-objective optimization (MOO) to ascertain optimal operating conditions for the system. The effect of (1) evaporator temperature, T (2) condenser temperature, T (3) Lower Temperature Circuit (LTC) condenser temperature, T (4) Mid Temperature Circuit (MTC) condenser temperature, T and (5) Cascade Condenser temperature difference, on three objective functions (COP, exergy efficiency, and overall plant cost) have been investigated employing a parametric analysis. Subsequently, quadratic equations for these objective functions are generated using the Box-Behnken method, and MOO utilizing the Genetic algorithm has been performed to maximize COP and exergy efficiency while minimizing the overall cost rate. The decision-making techniques TOPSIS and LINMAP are used to retrieve a unique solution from the Pareto Front, and the system performance has been assessed at the optimal point. The optimization result demonstrates that for the 10-kW capacity TCRS, COP, exergy efficiency, and total plant cost are 0.71, 0.51, and 38262.05 $/year respectively, at optimum condition (T = -101.023 , T = 36.545 , T = - 69.047 and T = - 34.651 ). Exergy analysis identifies HTC compressor (19.3 %) and throttle valve (15.5 %) as key contributors to total exergy destruction, while economic analysis underscores capital and maintenance costs (72 %) as the primary contributors to the overall cost, with evaporator (43 %) and condenser (20 %) accounting for 63 % of this cost.
疫情后的能源危机以及日益严重的环境恶化，促使研究人员仔细审视制冷系统，这些系统是造成上述问题的主要因素，要使其对环境的影响降至最低并实现最高性能。因此，本研究旨在全面考察配备碳氢制冷剂（1-丁烯/庚烷/间二甲苯）的复叠式制冷系统（TCRS）。该系统专为超低温应用而设计，包括疫苗储存、速冻、冷冻食品保鲜、低温工艺以及气体液化。该研究将传统热力学分析与经济和环境影响评估相结合，最终通过多目标优化（MOO）来确定系统的最佳运行条件。通过参数分析研究了（1）蒸发器温度T、（2）冷凝器温度T、（3）低温回路（LTC）冷凝器温度T、（4）中温回路（MTC）冷凝器温度T和（5）复叠式冷凝器温差对三个目标函数（性能系数、火用效率和全厂总成本）的影响。随后，使用Box-Behnken方法生成这些目标函数的二次方程，并利用遗传算法进行多目标优化，以最大化性能系数和火用效率，同时最小化总成本率。使用TOPSIS和LINMAP决策技术从帕累托前沿检索唯一解，并在最优点评估系统性能。优化结果表明，对于10千瓦容量的TCRS，在最佳条件（T = -101.023 ，T = 36.545 ，T = -69.047 和T = -34.651 ）下，性能系数、火用效率和全厂总成本分别为0.71、0.51和38262.05美元/年。火用分析确定HTC压缩机（19.3%）和节流阀（15.5%）是总火用损失的主要贡献者，而经济分析强调资本和维护成本（72%）是总成本的主要贡献者，其中蒸发器（43%）和冷凝器（20%）占该成本的63%。
