This book is the result of a long-term co-operative research and professional development programme between the Instituto de Investigaciones Electricas (IIE), Mexico, and the University of Salford, UK. It provides the design basis for the fabrication of small and large scale commercial absorption heat pump systems, and includes a comprehensive treatment of the economics of heat pump systems. It charts the development of heat pump technology from theoretical principles to the operation of practical systems for the purification of water, both for human consumption and a wide variety of industrial purposes. In addition to the increasing demand for potable water there is a rapidly increasing demand for clean water in industries ranging from foodstuffs and pharmaceuticals to electronics. This book will be essential reading for industrial engineers and others concerned with the cost-effective, environmentally friendly production of clean water.