科研之友
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摘要
Sleeping is an important human activity and heating system is needed for a comfort sleeping thermal environment in winter. By combining the merits from both an air source heat pump (ASHP) and a Chinese-Kang heating system, a prototype bed-based ASHP (B-ASHP) system has been proposed, and several design/operating parameters were experimentally and numerically studied previously. A numerical study using a digital thermal manikin (DTM) on the impacts of four influencing factors, i.e., operating mode, bed surface temperature (t(bed)), thermal resistance of mattress (R-mat), and thermal resistance of quilt (R-q) on sleeping thermal comfort was carried out, and the study results are reported in this paper. The numerical study results suggested that firstly, to maintain a suitable sleeping thermal environment, the use of only the Horizontal section (H-Section) of the bed-based heating terminal of the B-ASHP system was adequate; however using the Horizontal and Vertical section (H+V-Section) could minimize the temperature difference between the micro-climate close to the bed and outside environment, although with a higher energy consumption. Secondly, t(bed) of the bed-based terminal should be carefully selected, and a t(bed) of 44 degrees C could both meet the requirement of thermal comfort and acceptable operating efficiency of the B-ASHP system. Thirdly, the use of a mattress would reduce the heat transfer from the bed-based terminal to a sleeping person and indoor space, however an excessively higher R-mat of mattress would reduce the heating capacity and operating efficiency, leading to a cold sleeping environment. Finally, the use of a quilt would help prevent the heat loss from a sleeping person, thereby maintaining a warmer sleeping thermal environment, however a higher-than-necessary R-q of quilt would decrease the sleeping thermal comfort.
