Abstract The main characteristics of the equipment in the air conditioning and solar energy installations are presented with energy and exergy analyses, showing how to calculate the irreversibilities and the exergy efficiency. The chapter starts with absorption refrigerators, describing the simple cycle and showing the energy and exergy analysis of each one of its components. A similar treatment is followed for adsorption refrigerators. The adsorption/desorption process and the operation of a single-effect machine are described. Next, the energy and exergy analysis of an air treatment unit with a rotary desiccant dryer is considered. After, an analysis of the basic air conditioning processes is done, showing the differences between conventional energy and exergy analysis. Later, ventilation systems are explained, using exergy to evaluate the advantages and limitations of heat recovery. Finally, solar energy systems are studied, by applying exergy analysis to photovoltaic cells, thermal collectors and to hybrid panels.