Abstract: Through analyzing the energy flow of five consecutive loops extracting energy from the airconditioned rooms to the surroundings, this paper proposes an energy flow mathematical model of the whole air conditioning loop with water-cooled chiller, and draws an energy flow diagram based on the data derived from a typical allair system of an office building at Guangzhou. It also quantitatively discusses the variation principles and relations of energy flow, presents the magnitude and direction of energy flow, energy balance and loss of systems as well as recognizes the dominant energy flows. Finally, a theoretical analytic model is suggested for the energy-consuming and energy-saving of central air conditioning system.

Key words: central air conditioning system; water-cooled chiller; mathematical models; energy flow; all-air system