Organic Molecules for Application of Engineering Thermodynamics: Refrigeration and Organic Rankine Cycle

Abstract

This chapter discusses the application of organic molecules in engineering thermodynamics: being used as working fluid in refrigeration and the organic Rankine cycle. There are, in general, two points of view that may be adopted in the engineering thermodynamics: the macroscopic point of view and the microscopic point of view. Two applications of organic molecules in engineering thermodynamics, refrigeration and the organic Rankine cycle, are not at a molecular scale, but at a human scale.The chapter focuses on the performance of refrigeration system and the organic Rankine cycle that contain many molecules. Main methods of refrigeration can be classified as non-cyclic, cyclic, thermoelectric, and magnetic. Cyclic refrigeration can be classified as: vapor cycle and gas cycle. Vapor cycle refrigeration can further be classified as: vapor-compression refrigeration and vapor-absorption refrigeration. Organic molecules are always used as the working fluids in vapor-compression refrigeration cycle. Besides, organic molecules are also used as the working fluids in ORC that is an important technique for low-grade heat utilization. The development history, numbering system, classification, and requirements of organic refrigerant used in refrigeration system and ORC are also introduced. Keywords: cyclic refrigeration; engineering thermodynamics; non-cyclic refrigeration; organic molecules; organic Rankine cycle; vapor-compression refrigeration cycle; refrigerant