Magnesium-based thermochemical reactor with multiporous structures for medium-temperature solar applications: Transient modelling of discharge capability

Thermochemical energy storage (TCES) reactions have attractive advantages compared with heat storage methods, such as extremely high energy storage densities (1440 and 3960 MJ m(-3)), no heat loss, and good transportability. In this study, a thermochemical reactor with gradient porosity using magnesium-based materials is designed. To study the functions and characteristics of thermochemical storage reactors, the related key parameters, such as velocity, temperature, conversion degree, conversion rate, and power, are analysed for the reaction space and heat transfer fluid (HTF) channel. In the heat release process, the highest temperature was 322 degrees C, and the duration times of the reaction were approximately 360 min, 200 min, 180 min and 75 min for different positions. Compared with the same-porosity condition, the maximum pressure in the gradient-porosity reactor was much lower. The maximum pressure was approximately 1.15 atm, 1.98 atm, 4.1 atm and 6.9 atm with different mixed steam flow rates, and the total power in the reaction process was approximately 190 W. In the HTF channel, the highest temperature was 295 degrees C, and it remained consistent for 250-270 min. The present model provides a valuable reference for practical engineering applications.

Automated summary

Thermochemical energy storage reactions have advantages of high energy storage densities, no heat loss, and good transportability. This study designed a thermochemical reactor with gradient porosity and analyzed the key parameters for reaction space and heat transfer fluid channel. The experimental results provide valuable reference for practical engineering applications, including the highest temperature, reaction durations, maximum pressure, and total power in the process.