It has long been recognized that realizing the potential for energy conservation and diversification by using heat pumps offers considerable benefits to the environment. Important work on more efficient and ozone-friendly working fluids will further enhance the case for greater support of heat pump research. This book contains the Proceedings of the Third International Energy Agency Conference held in Tokyo in March 1990. The main theme of the Conference, 'Heat Pumps - Solving Energy and Environmental Challenges', is explained in great depth, covering not only technical characteristics but economic factors and the role of government and other bodies in promoting research, and the uses of all types of heat pumps are also fully considered. As well as publishing the papers presented at the meeting, the book also contains the extensive complementary poster sessions from the Conference.