Pleasant sleep provision system during warm nights as a function of smart home

Abstract

The increase in the occurrence of warm nights in Japan is caused by the effects of global warming. A definition of warm nights is a temperature over 25 degrees Celsius during the night; warm nights are often observed in the middle of August in Japan and cause loss of sleep and deconditioning. Moreover, the effects of warm nights cause people to fall ill, especially those with heart disease tend to fall ill easily, which could lead to serious medical conditions. In order to provide a better environment for pleasant sleep during warm nights, this study presents a pleasant sleep provision system, which consists of four main functions. The system collects environmental and evaluation data to detect indoor comfort to determine which indoor comfort residents prefer using a networked sensor and web-based questionnaire. Then, functions of a heating, ventilation, and air conditioning and information provision are adapted for a bedroom and delivered to each person. To confirm the effectiveness of the proposed system, the system was installed in the bedrooms of two houses; two people lived in each house. An experiment was conducted for 20 days, 10 days of which were just for collecting basic data, and the other 10 days for using this system. In addition, to further evaluate the proposed system, the web page provided by the system collects the data of each participant's sleeping time and their preferences. In considering whether the predicted mean vote (PMV) preference was effective or not, 5 days of data of when the proposed system was not used were compared with 5 days of data of when the proposed system with the preference data was used. The results revealed that the proposed system (a) provided a better space for sleeping, (b) sleeping time was longer 5.7 min, (c) showed improved satisfaction of customized information for each person's PMV preference (7.72 percent), and (d) received a system satisfaction rating of 77.5 percent.