Control of the bed thermal environment by a ventilated mattress

Abstract

Thermal comfort affects the sleep quality and well-being of people. The effect of a ventilated mattress (VM with integrated localized heating on providing the necessary thermal conditions for comfort in the bed-microenvironment was studied. The VM has an exhaust opening located under the feet of a lying person. Air is sucked and transported inside the mattress by a small fan connected to the mattress. The benefit of using such a mattress is that it sucks and removes body-emitted bio-effluents, which prevents the pollutants to spread in the room. The air movement inside the mattress provides cooling to the body, which makes the bed micro-environment comfortable during the cooling season but may cause discomfort during the heating season. Therefore, the VM was further developed by implementing local heating. Full-scale experiments were performed in a climate chamber furnished with a single bed equipped with the VM. A full-size thermal manikin was used to simulate a person lying in the bed. The performance of the VM with regard to the provided body heating/cooling was studied at room air temperatures of 19, 23, and 28 ℃. The control of the thermal conditions in the bed-microenvironment was tested when the VM was operating at different airflow rates and local heating power. A reference condition at 23 ℃ without the VM in operation was assumed to provide thermal comfort in the bed. The performance of the VM was evaluated based on a comparison of the body dry heat flux from the segments and the whole body of the thermal manikin obtained with the VM in operation and during the reference condition. The results show that it was possible to achieve the same body heat flux at all studied room temperatures using the VM with localized heating as in the reference condition. The use of the VM combined with localized heating with control based on the individual needs of the user can be an efficient method for providing thermal comfort in a bed at a wide range of room air temperature. Energy can be saved by expanded lower and upper room temperature limits recommended in the standards.