The Effect of Ambient Temperature and Pressure on the Performance of Cavern-Based Compressed Air Energy Storage Plants

The performance of cavern-based Compressed Air Energy Storage systems is highly dependent on the ambient condition. In this work, the effect of ambient temperature and pressure on the round trip efficiency of this technology is investigated via exergy analysis. Three different cavern sizes 8k, 140k, and 450k cubic meters are considered. The result showed that the highest exergy destruction occurs in the intercooler, while the heat exchangers are most sensitive to weather variations. Also, low-pressure compressors and heat exchangers are more sensitive to the weather than their high-pressure counterparts. Detailed exergy analysis showed that for the large cavern size case, intercooler alone is responsible for 56% of exergy destruction of the plant in hot weather condition, followed by compressors and turbines group, cavern, heat exchangers and motors and generators with 20%, 9%, 8% and 7% of the total exergy destruction. Efficiency analysis revealed that cavern-based CAES plants have greater efficiency in cooler weather conditions, and the effect of ambient temperature and pressure on larger plants is smaller. The results of this work can serve as a guideline for predicting the effect of ambient condition on the efficiency of both cavern-based and regular compressed air energy storage systems.