Thermo-hydraulic performance of double pass solar air heater duct having semi-circular tubes and perforated blocks as artificial roughness. (March 2023)

• Record Type: Journal Article
• Authors: Hedau, Ankush; Saini, R.P.
• Is Part Of: Renewable energy. Volume 205(2023)
• Page Start: 543
• Page End: 562
• Publication Date: 2023-03
• Subjects: Double pass solar air heater -- Perforated block -- Artificial roughness -- Semi-circular tube -- Computational fluid dynamics -- Thermo-hydraulic performance; Renewable energy sources -- Periodicals; Power resources -- Periodicals; Énergies renouvelables -- Périodiques; Ressources énergétiques -- Périodiques; 333.794
• DOI: 10.1016/j.renene.2023.01.087
• Languages: English
• ISSNs: 0960-1481

Abstract

Abstract: Solar air heaters (SAH) are used to collect and convert the solar radiations into thermal energy for various thermal applications. Its thermo-hydraulic performance can be improved by using various geometries of artificial roughness that breaks the laminar sublayer on absorber plate. In view of the same, a 3-dimensional computational investigation is conducted to study the heat transfer and friction characteristics of a double pass SAH having transverse semi-circular tubes with rectangular perforated blocks as artificial roughness and its outcomes are reported under the present paper. The investigation is carried out for different parameters such as Reynolds number ( Re ), tube amplitude to duct-height ratio ( a/H ), relative blockage-height ratio ( e/H ) and open area ratio ( β ) within a range of 3000–19, 000, 0.2 to 0.5, 0.4 to 0.8 and 13%–30%, respectively. The results obtained through CFD simulations are also compared with the experimental results for a typical set of parameters and a maximum percentage deviation for Nusselt number and friction factor are found as 1.82% and 5.28% respectively. For a considered range of parameters, the maximum value of thermo-hydraulic performance parameter is achieved as 2.51 corresponds to Re of 3000, a/H of 0.3, e/H of 0.4, and β of 30%. Based on the obtained results, it is found that the perforated blocks having maximum value of β and minimum value of e/H results in improved thermo-hydraulic performance of a double pass SAH. The research output of the present study may be useful for designing and optimize the parameters of a double pass SAH for the low temperature applications such as space heating, solar drying and solar air conditioning.