Comparative study of air and argon gases between cover and absorber coil in a cylindrical solar water heater: An experimental study

Gholamabbas Sadeghi, Habibollah Safarzadeh* (Corresponding Author), Mehdi Bahiraei, Mehran Ameri, Mohsen Raziani

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

9 Citations (Scopus)

Abstract

In this study, the effect of various gases filling the space between the cover and the absorber coil on the thermal performance of a cylindrical solar water heater (CSWH) is experimentally investigated. Since the Prandtl number for argon gas is less than that for the air, the thermal performance of the CSWH increases. The experiments are conducted for mass flow rates of 2.5, 3, 3.5 and 4 kg/h. The results show that an increase in the flow rate leads to a decrease in the temperature difference the of water between the inlet and outlet of the coil due to reduction of the residence time of the fluid. The energy efficiency of the collector reaches its maximum at the mass flow rate until 3.5 kg/h, and then reduces at higher values of mass flow rate because the water temperature difference decreases dramatically. Hence, the optimum mass flow rate for a cylindrical collector is reported as 3.5 kg/h. The maximum energy efficiencies for argon and air are 52.14% and 48.17%, respectively. Finally, the constructed cylindrical solar water heater is also economically compared to a flat plate collector (FPC) and an electric water heater with similar thermal efficiency.
Original languageEnglish
Pages (from-to)426-436
JournalRenewable energy
Volume135
DOIs
Publication statusPublished - 2019
Externally publishedYes

Keywords

  • Solar energy
  • Cylindrical solar water heater (CSWH)
  • Copper coil
  • Temperature difference
  • Energy efficiency

Fingerprint Dive into the research topics of 'Comparative study of air and argon gases between cover and absorber coil in a cylindrical solar water heater: An experimental study'. Together they form a unique fingerprint.

Cite this