Influence of Nanoparticle Sizes Added to Refrigerant on the Evaporative Heat Transfer Coefficient of the Cooling Systems

Abdellahy, Eed Abdelhafez; Taher, Sherif Hady; Hussein, Ahmed Mohamed; Sayed, Ahmed Wafdy

doi:10.21608/erjsh.2022.160762.1086

Influence of Nanoparticle Sizes Added to Refrigerant on the Evaporative Heat Transfer Coefficient of the Cooling Systems

Document Type : Research articles

Authors

¹ Mechanical Engineering, Shoubra, Benha University, Cairo, Egypt

² Mechanical Engineering, Higher Technological Institute 10th of Ramadan city, 6th of October branch, Cairo, Egypt

10.21608/erjsh.2022.160762.1086

Abstract

In this paper, nano particle based refrigerant R134a has been used to increase the heat transfer performance of base refrigerant in the vapor compression refrigeration system. Various types of solid and oxide materials could be used as nano particles suspended in conventional and non-conventional refrigerants. The purpose of this research is to investigate the performance of vapor compression refrigeration system with and without using nano refrigerant. In air conditioners and refrigerators used in urban, R134a is the most popular alternative refrigerant. Due to these limitations, this refrigerant's heat transfer capacity is insufficient, which increases power consumption. Nano particles improve the refrigerant by enhancing it, which increases its heat transfer capacity and lowers power consumption. Here, an experimental test rig is designed and built with this objective in mind. The test section is an evaporator made of copper representatives and a horizontal tube in tube heat exchanger. The refrigerant is evaporated inside the inner tube furthermore, hot water passing through the inner tubes annulus supplies the heat load. Measurements were performed for heat flux ranged from 40 to 80 kW/m2, mass flux ranged from 255 to 350 kg/m2s using nano Al2O3 concentrations ranged from 0.25 to 1.2% and sizes 15, 25, 40 nm. The measurements showed that nano particles have a high thermal conductivity when suspended in the base fluid, they enhance the thermophysical properties and heat transfer characteristics of the base fluid when added to refrigerants.

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