Steven G. Penoncello earned his BS and MS in mechanical engineering from the University of North Dakota in 1978 and 1980, respectively. He earned his PhD in mechanical engineering from the University of Idaho in 1986. He has been a registered professional engineer in mechanical engineering in the state of Idaho since 1993. Dr. Penoncello has held academic positions at the University of North Dakota (instructor from 1980-1983, assistant professor from 1986-1988, and associate professor from 1988- 1990), and the University of Idaho (visiting assistant professor from 1985-1986, associate professor from 1990-1995, professor from 1995-2015, and professor emeritus since 2015). He has also served in administrative positions at the University of Idaho (Mechanical Engineering Department Chair from 1995-1999, Associate Dean for Research and Graduate Studies in the College of Engineering from 1999-2005, and Director of the Center for Applied Thermodynamic Studies [CATS] from 2005-2015). Dr. Penoncello has taught undergraduate and graduate courses in thermodynamics, heat transfer, fluid mechanics, air conditioning, solar engineering, refrigeration engineering, internal combustion engines, energy technology, and thermal energy systems design. His research involves the development of standard reference quality formulations for the calculation of the thermophysical properties of fluids and fluid mixtures of scientific and engineering interest. Dr. Penoncello has been an active member of the American Society of Mechanical Engineers (ASME) since 1978. He became a Life Member of the ASME in 2015. He has served as a member of the K-7 Committee on Thermophysical Properties in the Heat Transfer Division of the ASME from 1988-2013. He has also served as a mechanical engineering program evaluator for the Accreditation Board on Engineering and Technology (ABET), representing the ASME from 1999-2012. Dr. Penoncello's background in thermal energy systems design and analysis started during his master's research at the University of North Dakota. His master's thesis topic was the analytical modeling and experimental verification of an innovative heat pump system designed for cold climates. This work took a full system approach and involved the simultaneous application of thermodynamics, fluid mechanics, and heat transfer. In 1991, the faculty of the University of Idaho Department of Mechanical Engineering undertook the task to critically evaluate and update their undergraduate curriculum. During this process, a conscious decision was made to revise the curriculum to allow the undergraduate students to have a significant design experience in several areas of the discipline including solid mechanics and thermal sciences. This process resulted in several new design-based courses including the senior capstone design experience (two courses), an updated machine design course, and a new course in thermal energy systems design. Dr. Penoncello took the lead in the development of the thermal energy systems design course. This book represents a collection of the topics that he has taught in his course since 1992. Dr. Penoncello has coauthored one book, two book chapters, and over 35 technical papers in the area of thermophysical properties.