This book presents selected articles presented at the 2nd Energy Security and Chemical Engineering Congress (ESChE 2021). This collection of proceedings presents the key challenges and trends related to mechanical as well as materials engineering and technology in setting the stage for promoting the sustainable technological solution for the better world. The book discusses recent explorations and findings with regard to mechanical and materials, specifically the thermal engineering and renewable energy areas that are very relevant toward the establishment of sustainable technological solutions. This book benefits academic researchers and industrial practitioners in the field of renewable energy and material engineering for energy applications.