Liquid air energy storage (LAES) is a large-scale energy storage technology with great prospects. Currently, dynamic performance research on the LAES mainly focuses on systems that use packed beds for cold energy storage and release, but less on systems that use liquid working mediums such as methanol and propane for cold energy storage and release, which have better heat transfer performance. Meanwhile, existing studies have failed to take into account the mutual influence between the charging and discharging processes, as well as the multi-cycle performance. In response to these issues, this article develops a dynamic model of an LAES system that uses liquid methanol and propane for cold energy storage and release and introduces solar energy to improve round-trip efficiency. Subsequently, in-depth dynamic research is conducted on the proposed solar-aided liquid air energy storage (SALAES) system. The novelty of this work lies in the detailed structural design and dynamic modeling of multi-stream heat exchangers, the whole process dynamic simulation and performance evaluation of the SALAES system, and multi-cycle performance analysis based on the quantified cold energy loss. The research results indicate that under design conditions, the liquid air is generated at 30.3 s after the start of the charging process, and it takes about 640 s to make the air liquefaction rate reach 95% of the final stable value. The exhaustion of stored hot molten salt can make salt-air heat exchangers trip, leading to a 23.1% decrease in round-trip efficiency and a 12.2% decrease in exergy efficiency. In consideration of cold energy loss, using the rated discharging duration mode, the system will fully recover to the design performance after several cycles. Under the rated discharging flow rate mode, although the temperature of the cold storage fluids recovers faster, for every 5% increase in cold storage fluid temperature rise, the operation duration decreases by about 0.6 h.
Whole process dynamic performance analysis of a solar-aided liquid air energy storage system: From single cycle to multi-cycle
Desideri U.
2024-01-01
Abstract
Liquid air energy storage (LAES) is a large-scale energy storage technology with great prospects. Currently, dynamic performance research on the LAES mainly focuses on systems that use packed beds for cold energy storage and release, but less on systems that use liquid working mediums such as methanol and propane for cold energy storage and release, which have better heat transfer performance. Meanwhile, existing studies have failed to take into account the mutual influence between the charging and discharging processes, as well as the multi-cycle performance. In response to these issues, this article develops a dynamic model of an LAES system that uses liquid methanol and propane for cold energy storage and release and introduces solar energy to improve round-trip efficiency. Subsequently, in-depth dynamic research is conducted on the proposed solar-aided liquid air energy storage (SALAES) system. The novelty of this work lies in the detailed structural design and dynamic modeling of multi-stream heat exchangers, the whole process dynamic simulation and performance evaluation of the SALAES system, and multi-cycle performance analysis based on the quantified cold energy loss. The research results indicate that under design conditions, the liquid air is generated at 30.3 s after the start of the charging process, and it takes about 640 s to make the air liquefaction rate reach 95% of the final stable value. The exhaustion of stored hot molten salt can make salt-air heat exchangers trip, leading to a 23.1% decrease in round-trip efficiency and a 12.2% decrease in exergy efficiency. In consideration of cold energy loss, using the rated discharging duration mode, the system will fully recover to the design performance after several cycles. Under the rated discharging flow rate mode, although the temperature of the cold storage fluids recovers faster, for every 5% increase in cold storage fluid temperature rise, the operation duration decreases by about 0.6 h.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
