Energy, exergy, and sensitivity analyses of underwater compressed air energy storage in an island energy system

Abstract

Summary An underwater compressed air energy storage (UWCAES) system is integrated into an island energy system. Both energy and exergy analyses are conducted to scrutinize the performance of the UWCAES system. The analyses reveal that a round‐trip efficiency of 58.9% can be achieved. However, these two analyses identify different directions for further improvement. The heat exchangers, expanders, compressors, electric motors, and generators account for the most exergy destruction. A sensitivity analysis is also conducted to investigate the importance of different input parameters on the round‐trip exergy efficiency of the UWCAES system. The results of both local and global analyses show that the round‐trip exergy efficiency is most sensitive to the isentropic efficiency of the expanders and compressors, and the efficiencies of the electric motors and generators. The impacts of the heat exchangers, the self‐discharge rate of the air accumulator, the inner diameter of the pneumatic pipelines, and the insulation thickness of the hot‐oil tank on the round‐trip exergy efficiency are shown to be highly nonlinear.

Thermal performance of a fixed‐plate air‐to‐air energy recovery system for building application in hot and humid environment

“…These systems work based on principle and process to recover or exchange heat and/or moisture between two different airstreams at different temperatures and humidities. 7,8 This process is essential in maintaining acceptable IAQ whilst keeping energy costs low and reducing overall energy consumption and carbon dioxide emissions. 9,10 By categorising these systems into process-based, they can be divided into sensible and total energy recovery systems.…”

“…The air‐to‐air energy recovery systems have been used quite extensively in building HVAC systems to reduce heating and cooling loads caused by ventilation. These systems work based on principle and process to recover or exchange heat and/or moisture between two different airstreams at different temperatures and humidities 7,8 . This process is essential in maintaining acceptable IAQ whilst keeping energy costs low and reducing overall energy consumption and carbon dioxide emissions 9,10 …”

An innovative s olar‐powered natural g as‐based compressed air energy storage system integrated with a liquefied air power cycle

“…To improve the thermal efficiency and reliability of a CAES system various thermodynamic cycle can be used and integrated with renewable energy-based systems. Wang et al [24] proposed and analyzed an underwater CAES system driven by marine renewable energies for an island using energy and exergy thermodynamic analyses. Cold and hot thermal oil loops were utilized in their studies to improve the system performance.…”

Application of the concept of a renewable energy based‐polygeneration system for sustainable thermal desalination process—A thermodynamics' perspective

“…Some of the scientists also analyzed the systems in terms of entropy and exergy balances. 6,18,[32][33][34][35][36] In addition, some articles included an economic assessment of their developed multigeneration systems. 27,[37][38][39][40][41] These studies summarized in Table 1 prove that by integrating waste streams into other systems, a significant increase in the overall energetic and exergetic efficiencies can be achieved.…”

“…The methodologies adopted by most of the scientists in the published literature are based on thermodynamic analysis evolving around mass and energy balances applied on various components of the proposed system. Some of the scientists also analyzed the systems in terms of entropy and exergy balances 6,18,32-36 . In addition, some articles included an economic assessment of their developed multigeneration systems 27,37-41 .…”