This study investigates the performance enhancement of parabolic trough concentrators (PTCs) with transparent insulation material shell (TIMS) of different diameters and thicknesses integrated into evacuated and non-evacuated heat collection elements (HCEs). The results show that non-evacuated TIMS-HCEs have higher energy and exergy efficiencies by up to 62.4 and 63.2%, compared to conventional evacuated HCEs, and by up to 109.2 and 110.9%, compared to conventional non-evacuated HCEs. At high flow rates and low fluid temperatures, the energetic performance of a conventional evacuated HCE is only 6.3% higher than that of the modified non-evacuated one. The modified design also enhances the circumferential temperature uniformity and shows a marginal drop in efficiency when the vacuum is lost. By simulating the PTC performance during four typical days, and without vacuum, the proposed design increased the daily useful heat gain by up to 1.36 and 5.64 kWh, compared to conventional evacuated and non-evacuated HCEs, respectively. Hence, it is proposed as a low-tech alternative to HCE evacuation and as a method of boosting the performance of PTCs operating at low flow rates and high temperatures.

这项研究研究了将不同直径和厚度的透明绝缘材料壳（TIMS）集成到抽空式和非抽空式集热元件（HCE）中，以提高抛物线槽式集中器（PTC）的性能。结果表明，与常规的真空HCE相比，非真空的TIMS-HCE具有更高的能量和火用效率，分别高达62.4％和63.2％，与常规的非真空HCE相比，其能量和火用效率分别高达109.2和110.9％。在高流速和低流体温度下，常规抽空HCE的能量性能仅比改进型非抽空HCE的能量性能高6.3％。改进的设计还增强了圆周温度的均匀性，并且在失去真空时显示出效率的边际下降。通过模拟四个典型天（无真空）下的PTC性能，与常规抽空的和非抽空的HCE相比，拟议的设计将每日有用的热增益分别提高了1.36和5.64 kWh。因此，它被提议作为HCE疏散的一种低技术替代品，并且被认为是一种提高在低流量和高温下运行的PTC性能的方法。