Performance of solar-desiccant cooling system with Silica-Gel (SiO2) and Titanium Dioxide (TiO2) desiccant wheel applied in East Asian climates

Abstract

This paper shows the numerical investigation of the developed solar-desiccant cooling system applied in the East Asian climatic conditions with two different desiccant wheel coating materials – the Silica-Gel (SiO2) and the Titanium Dioxide (TiO2). The developed and validated numerical model of the system is currently used in the present study incorporating the two new materials in the desiccant wheel. The system was applied in temperate climate (Beijing and Tokyo), subtropical climate (Taipei and Hong Kong) and tropical climate (Manila and Singapore). The study showed that the specification of the solar-desiccant cooling system varies depending on the climatic conditions. It showed that the required flat plate collector area was getting larger from the temperate climate to the tropical climate. The storage tank requirement was getting bigger in the tropical climate compared to the subtropical and temperate climate. The volumetric flow rate of air was getting higher from temperate climate to tropical climate. In the comparison of the two materials, it was found that the Titanium Dioxide (TiO2) can support lower indoor temperature and humidity ratio than the Silica-Gel (SiO2) with the same specification of the solar thermal system and desiccant cooling system. In general, the solar-desiccant cooling system can provide the required indoor temperature and humidity ratio. However, for the hot and humid climate such as in tropical, large size of the solar thermal system is needed. In addition, higher volumetric flow of air to support the high cooling load is required. With regard to the new material, Titanium Dioxide, it is proven to be a good alternative material since it can provide lower indoor temperature and humidity ratio with higher cooling performance than the Silica-Gel.