ABSTRACT

In this paper, the effect of various zinc oxide aluminate spinel (ZnOAl₂O₃) and titanium oxide (TiO₂) nanoparticle concentrations on the thermal performance of the Diffusion Absorption Refrigeration (DAR) system is investigated. The main aim of the study is to increase the efficiency of DAR systems operating with low thermal performance. The first part of the study is experimentally tested on the system under the same ambient conditions in order to develop passive heat transfer using different nanofluids as working liquids, including ammonia/water solution containing different amounts (1 wt.% and 2 wt.%) of ZnOAl₂O₃ and TiO₂ particles. In the next part of the study, the tested system is designed in MATLAB/Simulink toolbox environment to compare experimental and numerical results. The use of nanofluids can increase the surface area expansion and the heat capacity of the fluid, resulting in a significant positive increase in heat transfer. The results clarify that the use of nanofluid as working fluid in the DAR system helps quicker evaporation, which reduces operating time and increases heat transfer in the generator. Compared to a base DAR system, the nanofluid solution with a 2 wt.% ZnOAl_2O3 nanoparticle concentration among other nanofluid and proportions causes a 57% increase in the coefficient of performance (COP) of DAR system.

摘要

本文研究了不同浓度的氧化锌铝酸尖晶石 (ZnOAl ₂ O ₃ ) 和氧化钛 (TiO ₂ ) 纳米粒子浓度对扩散吸收制冷 (DAR) 系统热性能的影响。该研究的主要目的是提高在低热性能下运行的 DAR 系统的效率。研究的第一部分是在相同环境条件下对系统进行实验测试，以开发使用不同纳米流体作为工作液体的被动传热，包括含有不同量（1 wt.% 和 2 wt.%）的氨/水溶液ZnOAl ₂ O ₃和 TiO _2的粒子。在研究的下一部分中，在MATLAB/Simulink工具箱环境中设计了被测系统，以比较实验和数值结果。使用纳米流体可以增加流体的表面积膨胀和热容量，从而显着增加传热。结果表明，在 DAR 系统中使用纳米流体作为工作流体有助于更快地蒸发，从而减少运行时间并增加发电机中的热传递。与基础 DAR 系统相比，具有 2 wt.% ZnOAl _2O3纳米粒子浓度以及其他纳米流体和比例的纳米流体溶液导致 DAR 系统的性能系数 (COP) 增加 57%。