Experimental and numerical investigation of a solar thermocline system for domestic water heating applications

• Published in: Journal of thermal analysis and calorimetry Vol. 149; no. 16; pp. 8787 - 8798
• Main Authors: Cheema, T. A., Javaid, H., Yildizhan, H., Tariq, M. H., Basharat, M. T., Subhani, Z. M., Fakhraei, O., Gorjian, S., Ahmadi, M. H., Pandey, C.
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 2024; Springer Nature B.V
• Subjects: Alternative energy sources; Analytical Chemistry; Charging; Chemistry; Chemistry and Materials Science; Cylindrical tanks; Heat; Heat storage; Heat transfer; High temperature; Inorganic Chemistry; Latent heat; Measurement Science and Instrumentation; Numerical analysis; Physical Chemistry; Pipes; Plants (botany); Polymer Sciences; Solar energy; Thermal energy; Vegetable oils; Water heating; Thermocline; Discharging; Charging; Renewable energy; Heat transfer fluid; Solar energy
• DOI: 10.1007/s10973-024-13148-x
• EISSN: 1588-2926
• ISSN: 1388-6150

Solar energy is one of the major sources of renewable energy and is being extensively harnessed. However, the intermittent nature limits solar energy to act as a stand-alone energy source. Therefore, it becomes imperative that effective and economical methods of storing solar energy on a large scale are developed. Both sensible and latent heat storage methods are available. The use of a thermal energy storage (TES) system is an attractive choice for high-temperature applications such as power generation plants. The present study investigates the development of a small-scale TES system using a concentrated solar collector. For this purpose, a small cylindrical thermocline tank with suspended copper pipes in the storage medium was developed, with vegetable oil working as the heat transfer fluid (HTF) and being circulated through the pipes to transfer heat to used engine oil as the storage medium. A pump continuously circulates the HTF through the charging loop. TES was designed and developed based on the results of numerical simulations before the physical development of the experimental setup. Numerical calculations were performed for determining heat transfer and charging characteristics using different heat storage materials. The numerical results showed that a maximum temperature of 67 °C was achieved in the 100-min simulation while in the experimental results, a maximum temperature of 64 °C was achieved. The experimental results were found in close conformance with the simulation results. The experiments showed that the flow rate of 0.088 L s
−1
was optimal and provided the highest temperature in the thermocline tank. The discharging experiment showed that the apparatus is viable to be used for 5.5 h for heating purposes. The salient feature of the study is an inexpensive TES system development and can act as a benchmark for the future development of renewable technology.