Hiroshi Yonekura

Initial Operation and Performance Evaluation of the Developed Solar Thermal and Electric Desiccant Cooling System

The system in this article was operated for electric heating and thermal storage, thermal storage and desiccant cooling, three days of controlled system operation, and a one-day actual outdoor air conditions operation. Results show that almost 9 h of electric heating is needed to store sufficient thermal energy and that same thermal stored energy is barely enough to support the desiccant cooling operation for only 7 h. It is also shown that excess thermal energy in the tank from the previous days operation cannot support the early-hour desiccant cooling the following day.

A Study on Ventilation Systems for Removing Indoor House Dust

Abstract This study evaluated various ventilation strategies for efficiently removing house dust in the indoor environment. Experiments and simulations were performed to study the flow and diffusion fields that are affected by different locations and shapes of outlets. In this study, two kinds of ventilation strategies were considered i.e. ceiling exhaust and slit exhaust. In each case, experimental measurements showed that the characteristics of airflow within the whole room are generally similar except for airflow close to the outlet. CFD flow field and diffusion field simulations were also made. The CFD characteristics of airflow were similar to the experimental results. In the simulations, the volume–average concentration of house dust within the whole room decreased gradually. From the results, a conclusion can be drawn that the volume–average concentration of house dust within the whole room is lower in the case of slit exhaust than ceiling exhaust. After a ventilation period of 30 minutes the CFD results showed removal efficiencies for the ceiling exhaust and slit exhaust of 15% and 26% respectively at a low air change rate of 0.5 h–1, while the removal efficiencies of ceiling exhaust and slit exhaust are 51% and 57% respectively at a high air change rate of 2.5 h–1.

Application of Desiccant Heating, Ventilating, and Air-Conditioning System in Different Climatic Conditions of East Asia Using Silica Gel (SiO 2 ) and Titanium Dioxide (TiO 2 ) Materials

This chapter shows the numerical investigation of the developed solar–DHVAC 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 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–DHVAC system varies depending on the climatic conditions. In the comparison of the two materials, it was found that the TiO2 can support lower indoor temperature and humidity ratio than the SiO2 with the same specification of the solar thermal system and DHVAC system. In general, the solar–DHVAC 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.