[1] Zhang TaoHan JitianChen Changnian, Kong LingjianLiu Yang,. Experiment and numerical simulation on flow and heat transferin all-glass evacuated tube solar collectors [J]. Journal of Southeast University (English Edition), 2016, 32 (4): 489-495. [doi:10.3969/j.issn.1003-7985.2016.04.016]

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Experiment and numerical simulation on flow and heat transferin all-glass evacuated tube solar collectors()

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Journal of Southeast University (English Edition)[ISSN:1003-7985/CN:32-1325/N]

Volumn:

32

Issue:

2016 4

Page:

489-495

Research Field:

Energy and Power Engineering

Publishing date:

2016-12-20

Info

Title:

Experiment and numerical simulation on flow and heat transferin all-glass evacuated tube solar collectors

Author(s):

Zhang TaoHan JitianChen Changnian;  Kong LingjianLiu Yang

School of Energy and Power Engineering, Shandong University, Jinan 250061, China

Keywords:

all-glass evacuated tube solar collectors;  the solar-assisted fuel cells;  field synergy principle;  entransy dissipation

PACS:

TK515

DOI:

10.3969/j.issn.1003-7985.2016.04.016

Abstract:

The experimental study of natural convection in all-glass evacuated tube solar collectors is performed through the experimental platform of the solar-assisted fuel cell system. The experimental facility includes solar collectors with different length and diameter tubes, different coating materials, and with/without guide plates, respectively. Three-dimensional mathematical models on natural and forced convections in the solar collectors are established and the experimental data is validated by field synergy and entransy principles. The results of natural convection show that the water temperature increases and thermal efficiency decreases gradually with the evacuated tube length. The thermal efficiency increases when absorption rates increase from 0.95 to 1.0 and emission rates decrease from 0.16 to 0.06. The thermal efficiency of solar collectors is increased after being equipped with the guide plate, which is attributed to the disappearance of the mixed flow and the enhancement of the heat transfer at the bottom of the evacuated tube. The results of forced convertion indicate that the Reynolds, Nusselt and entransy increments of the horizontal double collectors are higher than those of the vertical single collector while the entransy dissipation is lower than that of the vertical single collector. It is concluded that the solar collectors with guide plates are suitable for natural convection while the double horizontal collectors are suitable for forced convection in the thermal field of solar-assisted fuel cell systems with low and medium temperatures.

References:

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Memo

Memo:

Biographies: Zhang Tao(1974—), male, doctor; Han Jitian(corresponding author), male, doctor, professor, jthan@sdu.edu.cn.
Foundation items: The National Natural Science Foundation of China(No.51376110, 51541604), the Major International(Regional)Joint Research Project of the National Natural Science Foundation of China(No. 61320106011).
Citation: Zhang Tao, Han Jitian, Chen Changnian, et al.Experiment and numerical simulation on flow and heat transfer in all-glass evacuated tube solar collectors[J].Journal of Southeast University(English Edition), 2016, 32(4):489-495.DOI:10.3969/j.issn.1003-7985.2016.04.016.

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