Entransy analysis and application of a novel indoor cooling system in a large space building

Abstract

Researchers are giving increased attention to large space buildings such as airports and railway stations because of the high energy consumption of their indoor cooling systems. The indoor cooling system of a large space building is essentially a heat transfer process among several heat sources and heat sinks. Entransy analysis and T–Q diagrams are clear and direct methods for describing the heat transfer process in large space buildings. Based on entransy dissipation, the equivalent thermal resistance can be defined in order to evaluate the indoor cooling systems in large space buildings. Minimizing thermal resistance is the best way to achieve high-temperature cooling. Methods for reducing the equivalent thermal resistance from the heat sources to the heat sinks in large space buildings include simplifying the heat transfer process, reducing mixture loss among heat sources, minimizing unnecessary mixing of hot and cold fluids, and handling solar radiation directly. Based on this analysis, a radiant floor and displacement ventilation system is proposed. Compared with a conventional jet ventilation system, the radiant floor system has lower equivalent thermal resistance, especially for direct solar radiation. The new system was applied in Xi’an Xianyang International Airport, and it demonstrated approximately 34% better energy performance compared to the conventional system.