- Title
- A phase change calcium looping thermochemical energy storage system based on CaCO3/CaO-CaCl2
- Creator
- Wu, Sike; Zhou, Cheng; Tremain, Priscilla; Doroodchi, Elham; Moghtaderi, Behdad
- Relation
- Energy Conversion and Management Vol. 227, Issue 1 January 2021, no. 113503
- Publisher Link
- http://dx.doi.org/10.1016/j.enconman.2020.113503
- Publisher
- Elsevier
- Resource Type
- journal article
- Date
- 2021
- Description
- Calcium looping thermal energy storage (CaL-TES) is promising because of its high operating temperature, excellent energy storage density, and low material cost. However, a significant problem with the CaL-TES system is the rapid degradation of CaO. To overcome this degradation problem and also improve the energy storage performance, a novel phase change calcium looping thermal energy storage (PCCaL-TES) process has been developed based on the solid solution system of CaCO3/CaO-CaCl2. In the charging process of the PCCaL-TES system, surplus energy is stored via sensible heat, latent heat, and chemical energy with the calcination and melting of the solid solution CaCO3/CaO-CaCl2. In the discharging process, the carbonation and solidification of CaCO3/CaO-CaCl2 takes place and thus the stored energy is retrieved. Compared to the conventional CaL-TES system, the innovative PCCaL-TES system can help maintain a high activity of CaO over long-term operation due to the enhanced heat and mass transfer in the liquid-state carbonation. In this study, the energy storage performance of PCCaL-TES was assessed using the simulation package Aspen Plus v10. According to the modeling results, the PCCaL-TES system can achieve a round-trip efficiency of up to 49% and an energy storage density of nearly 1.5 GJ/m3, presenting improvements of about 4% and 20%, respectively, compared with the conventional CaL-TES system. Meanwhile, a parametric analysis was carried out to examine the effect of key operating parameters on the system performance of PCCaL-TES. The calculations show that the round-trip efficiency of the PCCaL-TES system can be improved by raising the mole fraction of CaCl2, increasing the carbonator temperature, or employing an optimum carbonator pressure. It was also found that a low mole fraction of CaCl2, a high activity of CaO, or a low temperature of CO2 storage was beneficial to achieving a high energy storage density. Finally, the impact of other operating factors on the round-trip efficiency of PCCaL-TES was summarized in a sensitivity analysis. It revealed the round-trip efficiency of the PCCaL-TES system was dominantly determined by the performance of the CO2 turbine (W-TURB) and compressor (W-COMP), the gas–liquid heat exchanger (HX3) and the exhaust CO2 cooler (CL3).
- Subject
- thermal energy storage; phase change calcium looping; calcium chloride; thermochemical energy storage; SDG 13; Sustainable Development Goals
- Identifier
- http://hdl.handle.net/1959.13/1460673
- Identifier
- uon:46027
- Identifier
- ISSN:0196-8904
- Language
- eng
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