Simulated Performance of Packed Bed Solar Energy Storage System having Storage Material Elements of Large Size - Part I

Packed bed or rock bed is very commonly known thermal energy storage component for solar air heaters. The major concern for design of packed bed energy storage system is to maximize the heat transfer with minimum pressure drop or pumping power. Under the given operating conditions, system parameters could affect heat transfer and pressure drop in the bed considerably. An attempt has been made to report the simulated performance of a packed bed solar energy storage system. Large size storage material elements of five different shapes have been used to carry out the present simulation study. Nusselt number and friction factor correlations reported by the authors under previous experimental study have been utilized to analyze the packed bed energy storage system for a range of system and operating parameters. Performance of the system has been evaluated based on temperature distribution, thermal energy stored and available energy stored in the bed, energy consumption by fan to propel air through the bed and thermal efficiency of the collector as a function of system and operating parameters. In present part of the paper, various component models of packed bed solar energy storage system and development of computer program have been reported. Results of simulated system performance have been reported and discussed in Part-II and III of this paper.