The Effect of Nanoadditives in Natural Ester Dielectric Liquids: A Comprehensive Review on Stability and Thermal Properties

Numerous experimental investigations were carried out by several researchers exploring vegetable oils as substitutes for transformer oil since these vegetable oils are biodegradable. Also, their usage may reduce the negative environmental impact of other traditional oils. Additionally, since today’s mineral oils are made from petroleum-based materials, they will ultimately run out in the near future. Vegetable oils might, therefore, be a contender to take the place of mineral oils in transformer applications. Vegetable oils are natural esters and are triglycerides of fatty acids that can be extracted from a wide variety of plants. Natural esters are more cost-effective than synthetic esters, and they are also abundant in many countries. This article provides a comprehensive review of natural ester-based nanofluids (NFs). First, the necessity, benefits, and drawbacks of natural esters are all discussed. Methods used to improve the effectiveness of natural esters and overcome their disadvantages are presented. Then, the concept of NFs is introduced, and recent experimental research on dielectric NFs is reviewed in detail, including preparation methodology, stability inspection, and thermal properties. Finally, all physical mechanisms behind the obtained results are discussed and clarified.