Numerical and Experimental Investigation of Thermo-Hydraulic Performance Enhancement of Water-Cooled Photovoltaic Modules Using a Helical Pipe Network with Twisted Tape Inserts

High and spatially non-uniform temperatures reduce the electrical output of photovoltaic (PV) modules and accelerate hotspot-related degradation. While previous research has looked into water-cooled PV/T systems and the use of twisted-tape inserts as separate solutions, there's a noticeable absence of studies that combine these approaches. Specifically, there is a lack of investigation into optimizing the arrangement of cooling pipes before incorporating internal flow enhancements. Moreover, experimental evidence is essential to confirm if such a dual strategy can genuinely improve the performance without imposing significant hydraulic disadvantages. This research directly tackles these issues by introducing and validating a two-step optimization strategy for water-cooled PV/T modules. Our work commenced with a computational assessment of four different helical pipe arrangements (۱۰۰ × ۱۵۰, ۱۰۰ × ۱۰۰, ۱۰۰ × ۵۰, and ۸۰ × ۸۰ mm). After this initial evaluation, the most promising configuration was further refined by adding either four or ten twisted-tape inserts. The best-performing layout was then enhanced using four and ten twisted-tape inserts. Simulations in three dimensions, investigating conjugate heat transfer, were performed using ANSYS Fluent. These simulations were carried out under a heat flux load of ۸۰۰ W/m², with incoming water at a temperature of ۲۵ °C, and across a range of Reynolds numbers from ۵,۰۰۰ to ۱۱,۰۰۰. The configuration featuring an ۸۰ × ۸۰ mm layout emerged as the optimal baseline. This setup successfully lowered the average temperature of the PV surface to ۴۵.۶۲ °C when the Reynolds number was ۱۱,۰۰۰. Concurrently, it achieved an electrical efficiency of ۱۶.۰۵% and an electrical power output of ۲۰۵.۴۹ W. The subsequent introduction of ten twisted-tape inserts led to a further reduction in temperature, bringing it down to ۴۲.۳۰ °C. This enhancement also boosted the electrical efficiency to ۱۶.۴۴% and the power output to ۲۱۰.۴۸ W. To confirm these findings, experimental validation was conducted. The results from these experiments showed mean absolute percentage errors of ۱.۴۶% for the baseline setup and a slightly lower ۱.۲۳% for the configuration enhanced with inserts. An important consideration, the pumping power required for these systems remained below ۳ W across all tested conditions. The distinct contribution of this research lies in its comprehensive approach, which unifies several key aspects within a single design framework. This includes optimizing the helical pipe layout, harnessing the flow enhancement provided by twisted tapes, evaluating the uniformity of temperature, and undertaking experimental validation of the thermo-hydraulic performance. This integrated methodology effectively demonstrates that improvements in hotspot management and overall electrical performance can be realized without incurring substantial demands on hydraulic energy.

کلیدواژه ها:

Photovoltaic cooling ، Twisted tape inserts ، Conjugate heat transfer ، Temperature Uniformity ، Hotspot mitigation ، Thermo-hydraulic Performance ، Photovoltaic/thermal