Hazarika, Richita and Majumdar, Rudrodip and Mahapatra, Sadhan and Saha, Sandip K
(2025)
Sensible heat storage performances of Hytherm 600 oil and energy-harnessing features of glycol-water mixture under simultaneous charging and discharging conditions.
Thermal Science and Engineering Progress, 68 (104311).
Full text not available from this repository.
| Abstract: |
A sensible thermal energy storage (TES) system is studied using Hytherm 600 oil as the storage medium and a 30:70 ethylene glycol–water (EG-W) mixture as the discharging fluid, owing to its extended operating temperature range (−14 °C to 105 °C) at atmospheric pressure. The EG-W mixture alleviates the working limitations of pure water by lowering the freezing point and elevating the boiling point, making it suitable for solar thermal systems in colder climates and for low-temperature industrial heat recovery without pressurized systems. An immersed helical coil-aided cylindrical TES tank is used in the experimental setup. The charging-alone and SCAD modes are investigated for different oil-side charging temperatures (60, 75, 90 °C) and discharging flow rates (0.5, 1.25, and 2 L/min). A three-dimensional numerical model is developed, incorporating temperature-dependent thermophysical properties for both fluids. This helped capture the stratification characteristics and thermocline behaviour accurately. Case C1 (charging temperature of 90 °C; charging and discharging flow rates of 0.5 L/min) exhibited the highest thermal energy accumulation of 38,500.1 kJ within the TES tank due to low energy extraction, while Case C3 (charging temperature of 90 °C; charging flow rate of 1.25 L/min, discharging flow rate of 2 L/min) demonstrated increased heat extraction (890 kJ). Case A2 (charging temperature of 60 °C; charging flow rate of 0.5 L/min; discharging flow rate of 2 L/min) exhibited the highest sustained efficiency of 0.26–0.27 in the later stages of SCAD operation. Entropy generation increased notably during SCAD operations due to enhanced thermal mixing. Case C2 (charging temperature of 90 °C; charging flow rate of 0.5 L/min; discharging flow rate of 1.25 L/min) exhibited the highest cumulative entropy generation of 52.49 kJ/kg·K, and Case A1 (charging temperature of 60 °C, charging and discharging flow rates of 0.5 L/min) showed the lowest entropy generation (37.49 kJ/kg·K). The analyses establish that higher charging temperatures strongly promote stratification, effectively countering the mixing induced by higher discharge rates. These insights establish a crucial foundation for configuring effective TES systems with non-conventional discharging fluids for various low-temperature applications. |
| Item Type: |
Journal Paper
|
| Subjects: |
School of Natural and Engineering Sciences > Energy and Environment |
| Divisions: |
Schools > Natural Sciences and Engineering |
| Date Deposited: |
19 Nov 2025 08:39 |
| Last Modified: |
19 Nov 2025 08:39 |
| Official URL: |
https://www.sciencedirect.com/science/article/abs/... |
| Related URLs: |
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| Funders: |
Funding (RI/0324-10001261-001) from the IITB-IRCC internship program 2025 |
| Projects: |
* |
| DOI: |
10.1016/j.tsep.2025.104311 |
| URI: |
http://eprints.nias.res.in/id/eprint/3007 |
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