Heat transfer enhancement of a PCM-porous metal based heat pipe evacuated tube solar collector: An experimental study

• Published in: Solar energy Vol. 251; pp. 106 - 118
• Main Authors: Pawar, Vivek R., Sobhansarbandi, Sarvenaz
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.02.2023
• Subjects: Experimental study; Phase change material; Porous medium; Solar thermal collector; Thermal performance enhancement; Solar thermal collector; Thermal performance enhancement; Phase change material; Experimental study; Porous medium
• ISSN: 0038-092X; 1471-1257
• DOI: 10.1016/j.solener.2022.10.054

Heat pipe evacuated tube solar collectors (HPETCs) are utilized in solar water heating systems, however, their thermal performance drops due to the intermittency of solar radiation. To overcome this issue, in this study phase change material (PCM) embedded with Copper (Cu) porous metal is directly integrated within the HPETC. For the purpose of comparison, the performance of the proposed system was evaluated in parallel with a conventional HPETC system under similar conditions. The thermal performance of each system is assessed based on the variation of fin temperature, outlet water temperature, exergy, energy efficiency and cost analysis. The results showed that when the value of solar radiation is at its peak, an increase of nearly 21 °C peak temperature was achieved for the evacuated tube filled with PCM + Cu porous metal. After sunset, the fin temperature difference of 36.1 °C was found between the conventional evacuated tube and evacuated tube filled with PCM + Cu porous metal. Moreover, the maximum water outlet temperature difference of 8 °C, 10 °C and 11 °C were found between two systems around at 10 PM on April 9–11, respectively. The proposed system reported maximum energy efficiency of 85.64% while the conventional system reported maximum of 36.91% daily energy efficiency. Lastly, combined system has showed 11.57% and 9.43% saving in hot water production cost for lifetime (Lt) of 5 and 10 years at 5% interest rate, respectively. •Experimental study of HPETC system integrated with PCM-porous metal was performed.•Comparison was made between proposed system and conventional unit under similar B.C.•Results show max fin temperature difference of 36.1 °C between the two systems.•Maximum heat transfer rate enhancement of 24.5% for the proposed system was achieved.•The proposed system achieved maximum daily energy efficiency of 85.64%.