Shuichi Hokoi

Survey of Thermal Environment of Residences Using Air Conditioners in Surabaya, Indonesia

This chapter reports the results of a survey on the attitudes of residents towards the use of air conditioners in Indonesia. A questionnaire survey and measurements of the thermal environment were carried out. With increasing income, the percentage of residents who felt that air conditioning was necessary also increased. Once residents start to use air conditioners, they continue their use. When an air conditioner is used, the lowest room temperature ranges from 23 to 29 °C, which is lower than that observed in Japan. Air conditioners are typically used around 14:00 and during sleeping time; this is similar to the situation in Naha, a subtropical area of Japan. Also, the duration of air conditioner use is longer than that in Japan. As a result of these findings, the consumption of energy used for cooling is expected to increase in this area.

Passive Cooling Strategies to Reduce the Energy Consumption of Cooling in Hot and Humid Climates in Indonesia

This chapter proposes strategies for reducing the energy consumption of cooling in residences in hot and humid climates. Based on the results of field measurements and questionnaire surveys in Surabaya, Indonesia, a simulation of indoor thermal environments – with consideration of air conditioner operation – was conducted to evaluate energy consumption by air conditioners. This simulation program considers both heat and moisture transfers in building materials. The combined effects of building airtightness and the opening times of doors and windows for ventilation were examined. The simulation is conducted for the rainy season. Making the whole building airtight results in a small reduction in energy consumption, because the size of the air-conditioned area increases. Meanwhile, making only the air-conditioned room airtight is more effective for reducing cooling energy consumption. Regardless, nighttime ventilation of non-air-conditioned spaces is quite effective in reducing the sensible cooling load. In conjunction with economic growth and requirements for improving indoor environmental quality, energy consumption for cooling is expected to increase rapidly in hot and humid areas. Therefore, the introduction not only of high levels of insulation but also of airtightness, in addition to well-controlled ventilation, is required to achieve energy savings.

Thermal Sensation and Comfort in Hot and Humid Climate of Indonesia

In conventional air-conditioning design, the comfortable range is considered to be between temperatures of 25 and 27 °C and relative humidity of 40 and 60%; these numbers vary only slightly based on a person’s race and country. However, several studies conducted in regions with hot and humid climates show that the observed thermal comfort requirements often do not agree with those obtained from European-based studies. In this chapter, the results from the questionnaire surveys and measurements in residences in the hot and humid regions of Indonesia and Malaysia are shown. It was found that the residents use air conditioning at low temperatures for sleeping and that many people consider cold condition as “comfortable” and desire “cooler” conditions even if they feel “cold” in thermal sensation.

The effects of windblown sand on the deterioration of mural paintings in cave 285, in Mogao caves, Dunhuang:

The Mogao caves in, Dunhuang are a United Nations Educational, Scientific and Cultural Organisation (UNESCO) World Heritage Site located in the inland desert region of China. Within this site, cave 285 is one of the most important caves. Because a great deal of deterioration has taken place within this cave, and a large amount of research has been carried out on the environmental effects of these changes. Results show that the east wall has been least affected by moisture, solar radiation, and daylight compared to the other walls and ceiling. However, the effects of deterioration, including scratches, detachment, and discoloration, are nevertheless seen on the east wall. In this study, we investigated the effects of adhesion and the collision of windblown sand as factors contributing to the deterioration of the east wall. We conclude that sand blown by high-velocity wind has led to detachment, flaking, and losses to the east wall including fading of the paintings. Research and Development Center, Daiken Corporation, Tokyo, Japan Kyoto University, Kyoto, Japan Department of Architecture and Architectural Engineering, Kyoto University, Kyoto, Japan Tokyo National Research Institute for Cultural Properties, Tokyo, Japan Dunhuang Academy, Gansu, China Corresponding author: Daisuke Ogura, Department of Architecture and Architectural Engineering, Kyoto University, KyotodaigakuKatsura, Nishikyo-ku, Kyoto 615-8540, Japan. Email: ogurad@archi.kyoto-u.ac.jp