Analysis on thermodynamic performance of ancient pagodas considering flow heat transfer properties

Abstract

The optimization of cooling and ventilation systems is essential to the protection of ancient pagodas, which boast profound historical, cultural and tourism values. This calls for thorough investigation into the thermodynamic and flow heat transfer properties of the central airconditioning system (CACS) in the pagoda. In this paper, a thermodynamic model of the cooling tower is established in the principle of differential calculation, and verified through field test. On this basis, the author further discussed the impacts of drifting and reflux effect on the working performance of the cooling tower. The results show that: without considering the drifting effect, there is only a slight error between the measured inlet air enthalpy, inlet air temperature and inlet air relative humidity and the values simulated by the proposed model; in actual operation, the drifting of water vapour away from the cooling tower carries away some heat, leading to reduced temperature and increased relative humidity at the air inlet; the reflux ratio within the cooling tower is positively correlated with the water temperature, dry-bulb temperature and relative humidity at the outlet of the cooling tower, but negatively with the heat exchange amount of the tower, under different atmospheric dry-bulb temperatures, atmospheric relative humidities and gas-water ratios; the reflux of water vapour has a significant impact on the cooling performance of the cooling tower, and the impact is positively correlated to the reflux ratio. The research findings provide theoretical support for engineering applications like heating, cooling and ventilation in ancient pagodas.