Solar energy will play an important role in our future energy supply, to the advantage of both the environment and the economy. This book focuses on water-based solar heating technology, presenting basic principles on solar radiation and the solar heating system, including details on orientation and output, sizing, the solar collector, the solar circuit, heat exchangers, heat stores and overall system technology. A range of practical applications are described, such as multi- and single-family dwellings, pools, camp sites, sports facilities, schools and industry. The potential and diversity of solar energy is made clear with additional sections on solar electricity, passive solar and solar air heating.