Dynamic performance modeling and operation strategies for a v-corrugated flat-plate solar collector with movable cover plate

Highlights: • An automatic movable cover plate was applied to the flat-plate solar collector. • The movable cover plate could reduce heat loss and prevent overheating effectively. • The effects of physical parameters of movable cover plate were investigated. • The effects of operation strategies of movable cover plate were analyzed. Solar energy as one of the renewable and abundant energy resources, was often harvested by flat plate solar collectors (FPCs) for heating and hot water supply. However, the FPC suffered significant heat losses and overheating problems due to poor design or sometimes extremely adverse environmental conditions, which further limited its application and operation. In this study, an automatic movable cover plate (MCP) was applied to the v-corrugated flat-plate solar collector (VFPC), a dynamic heat transfer model was developed, and a comparative experiment was conducted to analyze the effects of MCP on heat loss and overheating performance. The influence of environmental and operating parameters was analyzed under three typical operation conditions: (I) heat collection in summer, (II) overheating in summer and (III) heat collection in winter. For Condition I, the MCP could decrease the temperature fluctuation of heat transfer fluid from 18.9 to 5.7 ℃ in cloudy weather. For Condition II, the MCP with high absorptivity and low emissivity value could reduce the collector "stagnation" temperature to a lower value. For Condition III, the MCP could reduce the total heat loss to 62.8% and decrease the heat demand of reverse circulation by 4.5 MJ in 48 h. The FPCs incorporated with novel MCP showed excellent performance on synergistically reducing heat loss and preventing overheating problems, demonstrating the advantages of applying flat plate collectors in more wide temperature ranges and variable environments.