Dynamic coupled thermal-and-electrical modelling of sheet-and-tube hybrid photovoltaic/thermal (PVT) collectors
Dynamic coupled thermal-and-electrical modelling of sheet-and-tube hybrid photovoltaic/thermal (PVT) collectors
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DOI：
10.1016/j.applthermaleng.2016.02.056
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发表时间：
2016-05-25
影响因子：
6.4
通讯作者：
Markides, Christos N.
中科院分区：
文献类型：
--
作者：
Guarracino, Ilaria;Mellor, Alexander;Markides, Christos N.
本文提出了一种带有片管式吸热器的光伏/热混合集热器的动态模型。通过使用高时间分辨率的真实气候数据，该模型用于评估每年产生的电能以及从热能输出中提供的生活热水（DHW）。该模型考虑了太阳能电池表面非均匀温度分布对其输出功率的影响，建立了一个非定常三维数值模型来估计这种集热器的性能。该模型允许改变PVT集热器的关键设计参数，以便在稳态和不同的操作条件和大气条件下研究每个参数对系统性能的影响。本文考虑的一个关键参数是PVT集热器中使用的玻璃罩的数量。结果表明，虽然热效率随着玻璃的增加而提高，但由于流体温度的升高和光学损耗的增加，电效率如预期的那样下降。本文还表明，在评估系统的年度性能时，使用动态模型和高分辨率的实际气候数据是至关重要的。1分钟输入数据的动态仿真结果表明，系统的热输出高度依赖于响应不同天气条件的控制参数的选择（泵运行、差动恒温控制器、流量选择等）。只有采用动态建模方法，控制参数对系统年度性能的影响才能被捕获和理解。本文还讨论了在红外光谱中使用具有改进光学特性（特别是降低吸收率/发射率）的太阳能电池，这将减少PVT集热器的热损失，而当应用选择性涂层时，电输出损失很小。(C) 2016年作者。Elsevier Ltd.出版。
In this paper we present a dynamic model of a hybrid photovoltaic/thermal (PVT) collector with a sheet-and-tube thermal absorber. The model is used in order to evaluate the annual generation of electrical energy along with the provision of domestic hot-water (DHW) from the thermal energy output, by using real climate-data at high temporal resolution. The model considers the effect of a non-uniform temperature distribution on the surface of the solar cell on its electrical power output An unsteady 3-dimensional numerical model is developed to estimate the performance of such a collector. The model allows key design parameters of the PVT collector to vary so that the influence of each parameter on the system performance can be studied at steady state and at varying operating and atmospheric Conditions. A key parameter considered in this paper is the number of glass covers used in the PVT collector. The results show that while the thermal efficiency increases with the additional glazing, the electrical efficiency deteriorates due to the higher temperature of the fluid and increased optical losses, as expected. This paper also shows that the use of a dynamic model and of real climate-data at high resolution is of fundamental importance when evaluating the yearly performance of the system. The results of the dynamic simulation with 1-min input data show that the thermal output of the system is highly dependent on the choice of the control parameters (pump operation, differential thermostat controller, choice of flow rate etc.) in response to the varying weather conditions. The effect of the control parameters on the system's annual performance can be captured and understood only if a dynamic modelling approach is used. The paper also discusses the use of solar cells with modified optical properties (specifically, reduced absorptivity/emissivity) in the infrared spectrum, which would reduce the thermal losses of the PVT collector at the cost of only a small loss in electrical output when the selective coating is applied. (C) 2016 The Authors. Published by Elsevier Ltd.