聚光光伏-热化学耦合利用系统热力学分析

Thermodynamic Analysis for a Concentrating Photovoltaic-thermochemical Hybrid System

本文建立了一种聚光光伏-热化学耦合利用系统的模型。系统利用抛物槽式聚光分频装置将光谱分成不同的两部分分别进行光伏和热化学转换,其中热化学模块以太阳能作为反应热驱动甲醇重整反应产生氢气进入燃气轮机发电。对系统进行了能量分析和拥分析,得出系统拥损失主要集中在光学拥损失,光伏模块能量转换过程的拥损失和热化学模块能量转换过程的拥损失这三项,分别占总损失的32.7%,32.2%和27.0%。研究了不同分频波段下的光伏模块输出功率、集热器甲醇转化率和系统发电效率,同时将该系统与相同条件下的纯光伏系统和纯热化学系统进行了性能比较。结果表明,系统发电效率最高可达26.0%,相应的最佳光伏匹配波段为450～870 nm,相比于同等条件下的纯光伏系统和纯热化学系统,系统发电效率分别提高了11.1和6.1个百分点。

In this paper, a novel model of a concentrating photovoltaic-thermochemical（CPV/TC）hybrid system is proposed. Solar spectrum is seperated into several parts to enable photovoltaic（PV）and thermochemical（TC） conversion by utilizing the parabolic trough concentrator with a spectral beam splitter. The TC module absorbs the solar energy to supply the reaction heat of methanol-steam reforming（MSR） that produces hydrogen for power generation. The energy and exergy analyses on the CPV/TC hybrid system are carried out. The results reveal that the exergy losses of the CPV/TC hybrid system are mainly concentrated on the optical exergy loss, the exergy loss in the process of PV conversion and the exergy loss in the process of TC conversion which account for 32.7%, 32.2% and 27.0% of the total, respectively. The output power of the PV module, the methanol conversion rate of the solar receiver and the overall system efficiency with different splitting wavebands are investigated.Moreover, the CPV/TC hybrid system is compared with a single PV or TC system. The results indicate that the optimal splitting waveband for the PV module is 450-870 nm and the overall power generation efficiency can reach 26.0% which is 11.1 and 6.1 percentage points higher than that of a single PV and TC system under the same conditions.