The fundamentals

Abstract

This chapter, at first, provides a synthetic picture of the present spread of heat pumps over the world market, also quoting some of the main producers. The most common types are shortly described too. In addition the thermodynamic fundamentals of their working principle are dealt with and the effect of irreversibilities on the heat pumps performances is stressed. The contribution of the different components to these irreversibilities is shortly illustrated together with that introduced by the unavoidable temperature difference between the evolving fluid and the external sources.