This paper establishes a numerical simulation model of the solar ventilation preheating wall in purpose of obtaining a simplify calculations method for the thermal efficiency that can be easily applied. Five structural parameters, such as height ratio H*, characteristic thickness δ*, porosity σ, corrugation concavity Lw, and corrugation degree W*, are introduced. The coupling relationship between them and the near-wall Reynolds number Re on the solar wall Nusselt number Nu, heat transfer coefficient Hε and differential pressure value Pdrop is investigated by numerical simulation. The system performance indexes present a power function law with respect to Re, and a quadratic exponential function law in relation to the logarithm of σ and other parameters. The calculated empirical coefficients are obtained using the LM optimization algorithm. The results indicate that the simplified calculation results of Nu number and differential pressure have a maximum deviation of 6.85% from the simulation results. The simplified calculation results of heat collection efficiency have an average error of 4.89% and a maximum error of 6.69% with the experimental test results. The accuracy of the corrected data is improved by nearly 10% on average compared with the corrected values achieved by the traditional calculation method. The results are in good agreement and provide a reference for engineering design.
Key words
solar energy /
numerical simulation /
ventilation /
preheating wall /
simplify calculations method
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References
[1] 黄德中, 沈吉宝. 建筑节能技术综述[J]. 太阳能学报, 2007, 28(6): 682-688.
HUANG D Z, SHEN J B.The energy saving of buildings[J]. Acta energiae solaris sinica, 2007, 28(6): 682-688.
[2] KENNA J P.The thermal trap solar collector[J]. Solar energy, 1983, 31(3): 335-338.
[3] HOLLICK J P.Unglazed solar wall air heaters[J]. Renewable energy, 1994, 5(1-4): 415-421.
[4] ZHANG T T, TAN Y F, ZHANG X D, et al.A glazed transpired solar wall system for improving indoor environment of rural buildings in northeast China[J]. Building and environment, 2016, 98: 158-179.
[5] CHOUDHURY C, CHAUHAN P M, GARG H P.Design curves for conventional solar air heaters[J]. Renewable energy, 1995, 6(7): 739-749.
[6] 张欢, 高煜, 由世俊, 等. 一种新型渗透式太阳空气集热器热性能的模拟研究[J]. 太阳能学报, 2013, 34(8): 1391-1397.
ZHANG H, GAO Y, YOU S J, et al.Simulation on the heat performance of a novel glazed transpired solar air collector[J]. Acta energiae solaris sinica, 2013, 34(8): 1391-1397.
[7] BANSAL P K, KAUSGIK S C.Diurnal response of solar air heaters[J]. Applied energy, 1981, 9(2): 107-120.
[8] ZHENG W D, ZHANG H, YOU S J, et al.Thermal performance analysis of a metal corrugated packing solar air collector in cold regions[J]. Applied energy, 2017, 203: 938-947.
[9] GAO M, WANG D J, LIU Y F, et al.A study on thermal performance of a novel glazed transpired solar collector with perforating corrugated plate[J]. Journal of cleaner production, 2020, 257: 120443.
[10] LI S, KARAVA P, SAVORY E, et al.Airflow and thermal analysis of flat and corrugated unglazed transpired solar collectors[J]. Solar energy, 2013, 91: 297-315.
[11] CELIK I B, GHIA U, ROACHE P J, et al.Procedure for estimation and reporting of uncertainty due to discretization in CFD applications[J]. Journal of fluids engineering, 2008, 130(7): 078001.
[12] KUTSCHER C F, CHRISTENSEN C B, BARKER G M.Unglazed transpired solar collector: heat loss theory[J]. Journal of solar energy engineering, 1993, 115(3): 182-188.
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