Performance analysis and optimization of a TEG-based compression hydrogen storage waste heat recovery system

Abstract

A considerable quantity of waste heat is produced while compressing hydrogen. The process can be optimized by converting heat energy into electricity by utilizing thermoelectric electricity generator (TEG). This paper presents a TEG-based compression hydrogen storage waste heat recovery system (TEG-CHWSR). The effects of compression ratio, mass flow rate and inlet temperature at the cold and hot side on the operation performance and energy recovery efficiency are studied by establishing a mathematical model. The results demonstrate that the hydrogen inlet temperature and mass flow rate significantly impact the maximum output power and corresponding conversion efficiency of TEG. The maximum hydrogen storage pressures corresponding to the four types of hydrogen storage tanks are different. The maximum output power range of TEG for four hydrogen storage tanks is 2.32–5.9 kW at the TEG length of 1 m. The maximum output power and optimal module length increase with the increased hydrogen mass flow rate, while the energy recovery efficiency firstly increases and then decreases, existing a maximum point. The inlet temperature and mass flow rate at cold side has little influent on the optimal length of the TEG module. However, it has impact on the output power and thermoelectric conversion efficiency of TEG.