Experimental investigation of a solar evacuated tube collector embedded with a heat pipe using different nanofluids and controlled mechanical exciting pulsations

• Published in: International Journal of Thermofluids Vol. 20; p. 100415
• Main Authors: Eidan, Adel A., Alsahlani, Assaad, Alshukri, Mohammed J., Alsabery, Ammar I.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.11.2023; Elsevier
• Subjects: Al2O3/based acetone; CuO/based acetone; Gravity assisted heat pipe (GA-HP); Nanofluid; Solar evacuated tube collector embedded with heat pipe (SETC-HP); Vibration pulses; CuO/based acetone; Gravity assisted heat pipe (GA-HP); Al2O3/based acetone; Solar evacuated tube collector embedded with heat pipe (SETC-HP); Nanofluid; Vibration pulses
• ISSN: 2666-2027; 2666-2027
• DOI: 10.1016/j.ijft.2023.100415

•Experimental investigation for six identical solar water heaters was conducted.•Evacuated tube collector's performance with two types of nano-working fluids was investigated.•The collector with two types of Nano fluid as well as vibrational pulses showed an enhanced performance.•The highest improvement percentage in the solar collector for nanofluids compared to acetone was 91%. Numerous studies have been conducted to enhance the thermal performance of evacuated tube solar thermal collectors using various techniques, such as different working fluids, concentrators, and modifications to the absorber design. This work presents a parametric study to improve the thermal performance of a solar-evacuated tube collector embedded with a heat pipe (SETCHP) by utilizing different types of nanofluids and controlled mechanical excitation. The experiment involved six identical SETCHPs operating under the same conditions, with one setup filled with pure acetone as a reference. The second and third setups were filled with (0.5% vol Al2O3)/based acetone and (0.5% vol CuO)/based acetone, respectively. The remaining three setups were modified by imposing controlled mechanical excitation with different frequencies (27–82 Hz) to investigate the effect of vibration on thermal performance. The results demonstrated that the optimal enhancement was achieved with mechanical vibration pulses at 82 Hz, improving efficiency by 91% and 86% with Al2O3/based acetone and CuO/based acetone, respectively. The enhancement percentage of effective heat transfer coefficient (EHTC) and convective heat transfer coefficient (CHTC) varied with solar intensity and vibration, with improvements ranging from 5 to 82% and 3–53%, 26–160% and 5–60%, and 6.5–140% and 6.5–54% for pure acetone, Al2O3, and CuO (0.5% vol) acetone-based nanofluids, respectively.