Energy performance analysis of a novel solar PVT loop heat pipe employing a microchannel heat pipe evaporator and a PCM triple heat exchanger
Energy performance analysis of a novel solar PVT loop heat pipe employing a microchannel heat pipe evaporator and a PCM triple heat exchanger
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DOI：
10.1016/j.energy.2018.10.192
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发表时间：
2019-01
期刊：
影响因子：
9
通讯作者：
T. Diallo;M. Yu;Jinzhi Zhou;Xudong Zhao;Samson Shittu;Guiqiang Li;J. Ji;David Hardy
中科院分区：
文献类型：
--
作者：
T. Diallo;M. Yu;Jinzhi Zhou;Xudong Zhao;Samson Shittu;Guiqiang Li;J. Ji;David Hardy
本文对一种新型的太阳能PVT回路热管（PVT-LHP）的能量效率进行了数值分析，该热管采用了一种新型的微通道蒸发器和一种新型的相变储热器。介绍了PVT-LHP系统的各个子模型（PVT模型、微通道集热器模型和新型PCM三重换热器模型）以及系统的集成模型。通过保证冷凝器和蒸发器的热平衡，求解了系统的集成模型。进行了参数分析，以评估环境参数（即太阳辐射，空气温度，风速），结构参数（即玻璃罩，吸收微通道热管的数量，PV电池封装因子），循环流体变量（即冷水入口温度和水的质量流量）对系统的能量性能的影响。新型PVT-LHP与传统的太阳能PVT-LHP系统进行了比较。结果发现，较低的太阳辐射、较低的环境空气温度、较高的风速、较高的填充系数、较低的冷水入口温度和较小的盖数导致模块的电效率提高，但热效率降低;而较高的冷水质量流量和更多的微通道热管数量会提高模块的热效率和电效率。研究还发现，太阳辐射、环境温度、盖板数、微通道热管数和填充因子的增加对系统的总体性能系数（COP）是有利的，而风速和冷水质量流量的增加是不利的。研究表明，存在一个最佳的覆盖数，微通道热管的数量和质量流量。在给定的设计条件下，光伏/LHP组件的电效率、热效率和总效率分别为12.2%、55.6%和67.8%，与传统系统相比，新型系统的总能量效率可提高28%，COP可提高2.2倍。本研究所建立之整合式电脑模型，可应用于新型PVT-LHP加热系统之设计与最佳化。
This study presents a numerical analysis of the energy efficiency for a novel solar PVT Loop Heat Pipe (PVT-LHP) employing a novel Micro-channel evaporator and a novel PCM heat storage exchanger. It presents a description of the different sub-models in the PVT-LHP system (the PVT model, the microchannel heat collector model and the novel PCM triple heat exchanger model) and the integrated model of the system. The integrated model of the system was solved by ensuring a heat balance at the condenser and the evaporator. A parametric analysis has been performed in order to assess the influence of the environmental parameters (i.e. solar radiation, air temperature, wind velocity), structural parameters (i.e. glazing cover, the number of absorbing microchannel heat pipes, PV cell packing factor), the circulating fluid variables (i.e. cold-water inlet temperature and water mass flow rate) on the energy performance of the system. The novel PVT-LHP has been compared with a conventional Solar PVT-LHP system. It was found that lower solar radiation, lower ambient air temperature, higher wind speed, higher packing factor, lower cold-water inlet temperature and a smaller cover number led to an enhanced electrical efficiency, but a reduced thermal efficiency of the module; whereas a higher cold-water mass flow rate and a greater number of microchannel heat pipes gave rise to both thermal and electrical efficiencies of the module. It was also found that an increase of solar radiation, ambient temperature, cover number, microchannel heat pipe number and packing factor are favourable factors for the overall COP (Coefficient Of Performance) of the system, whereas an increase of wind velocity and cold water mass flow rate are unfavourable. The study indicated the existence of an optimal cover number, number of microchannel heat pipes and mass flowrate. Under the given design conditions, the electrical, thermal and overall efficiency of the PV/LHP module were 12.2%, 55.6% and 67.8% respectively and the novel system can achieve 28% higher overall energy efficiency and 2.2 times higher COP compared to a conventional system. The integrated computer model developed in this study can be used to design and optimize the novel PVT-LHP heating system.