This book contains five chapters describing nanofluids, their correlations for thermophysical properties, experimental setup, and testing of the performance of nanofluids of different nanoparticle concentrations and the base fluid in a real-world building heating air coil. The study is supplemented by computational fluid dynamics and heat transfer modeling in a microchannel heat exchanger to cool electronic equipment and computer chips. Chapters 2 and 4 present many recent correlations of viscosity, thermal conductivity, density, and specific heat that are necessary for design calculations. Chapter 4 shows through data the challenges encountered in practical applications when the dispersion stability of nanofluids cannot be maintained long-term, resulting in degraded performance. Future research in developing robust surfactants and dispersants is recommended. The book will benefit future nanofluids researchers contemplating experimental and computational work.