Increasing the Device Performance of Recycling Double-Pass W-Ribs Solar Air Heaters

Chii-Dong Ho, Hsuan Chang, Zih-Syuan Hong, Chien-Chang Huang and Yu-Han Chen
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Chii-Dong Ho: Department of Chemical and Materials Engineering, Tamkang University, Tamsui, New Taipei 251, Taiwan
Hsuan Chang: Department of Chemical and Materials Engineering, Tamkang University, Tamsui, New Taipei 251, Taiwan
Zih-Syuan Hong: Department of Chemical and Materials Engineering, Tamkang University, Tamsui, New Taipei 251, Taiwan
Chien-Chang Huang: Department of Chemical and Materials Engineering, Tamkang University, Tamsui, New Taipei 251, Taiwan
Yu-Han Chen: Department of Chemical and Materials Engineering, Tamkang University, Tamsui, New Taipei 251, Taiwan

Energies, 2020, vol. 13, issue 9, 1-16

Abstract: The device performance of recycling double-pass solar air heaters with W-ribs by machining on both sides of the absorber plate is investigated experimentally and theoretically. It is emphasized that in comparing various design configurations, they should be compared for the increase of power consumption suffered by the air passing through the collector under the same air mass flow rate and working dimensions. Compared to those of the single-pass and flat-plate double-pass device, both effects of the external recycle and the artificial W-ribs by machining enhance the collector thermal efficiency in this study. This study proposes an optimal design of the recycling W-ribs double-pass device that is expected to consider the compensation between collector thermal efficiency improvement I W due to the external recycle and the increase of power consumption I P , W owing to pumping the air circulation in the two divided subchannels. The evaluation of a higher ratio of I W to I P , W leads to economic benefits. It has been observed that a relative higher ratio of collector thermal efficiency improvement to the increase of power consumption occurs at recycle ratio R = 0.5. The results indicated the turbulent intensity increment with the artificial W-ribs by machining on both sides of the absorber plate could compensate for the increase of power consumption with the consideration of economic feasibility. The operation of a recycling W-ribs solar air heater with two covers in a double-pass mode offers an inexpensive method of improving the collector thermal efficiency by about 76.65%. The advantage of the present device is evident and provides a feasible design to improve the solar air heater of which the promotion in turbulence effectively raises the convective heat-transfer coefficient. The collector thermal efficiency enhancement of the double-pass operation is much higher than that in the smooth plate under different recycle ratios and mass flow rates.

Keywords: artificial W-ribs; Heat-transfer efficiency; Nusselt number; power consumption; recycling solar air heater (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2020
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (2)

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