Off-design operation analysis of air-based high-temperature heat and power storage

摘要

High-temperature heat and power storage is a new mechanical energy storage technology which is capable of cogenerating heat and electricity at high overall efficiency. The technology has received much attention from the leading European energy companies and research institutes. Although a pilot plant of this system has already been built up and is being tested, the technology is still in developing stage and there is much to be found out about the details of the system operation and most likely more advanced configurations of that to emerge. This study presents a detailed energy analysis of the air-based design of the high-temperature heat and power storage technology with a certain focus on the effects of the partial-load operation of the system on its energetic performance. For this, an air-based design of the technology is modeled and thermodynamically analyzed for operation loads from 10% to 100%. The results show that, at nominal load, the system offers a power-to-power efficiency of about 28% and power-to-heat efficiency of 63%. These efficiency values change slightly when the load drops to 80%, but significantly fall when the load decreases further so that the power-to-power efficiency of the system at 30% operational load is zero. (C) 2020 Elsevier Ltd. All rights reserved.