An innovative fan control strategy aimed at responding to human physiological characteristics for comfort sleeping

Abstract

• Comfortable air speed interval of the fan under 6 operating conditions. • The trend of the skin temperature during sleep can be divided into 5 stages. • The dynamic air supply control strategy of fans can improve people's sleep quality. A comfortable sleeping environment can improve sleep quality. Electric fans are widely accepted as an effective method in South China to improve the thermal environment in summer when people are sleeping. To determine the proper fan control strategy under the all-night blowing mode, pre-sleep and during-sleep experiments were performed in a climate room. Under 6 operating conditions (28/30/32 °C, 50 %/80 % RH), subjective sensations (thermal sensation votes and sleep quality indexes) were recorded and objective physiological parameters (brain waves and skin temperature) were monitored. The results showed that the comfortable air speed interval before sleep was 0.15–1.44 m/s. The skin temperature showed a clear trend of first rising, then falling, stabilising, rising again, and finally rising with fluctuations throughout the night. Based on the characteristics of physiological parameters in different sleep periods, the sleeping time was divided into 5 stages to perform linear regression, and a dynamic air supply control strategy for fans that imitated the circadian rhythm of sleep was proposed. Compared with steady-state blowing, the sleep efficiency and proportion of deep sleep under this optimisation control strategy increased by 3.24 % and 3.59 %, respectively. This study provides a reference for fan control in a sleep environment.