Photovoltaic/thermal (PV/T) systems generate both electricity and useful heat from a single module, yet extracting heat efficiently from solar cells remains a critical bottleneck. Researchers have investigated wire-coil inserts within fluid circulation tubes as a passive enhancement method to improve heat transfer without active pumping or mechanical complexity.
Using computational fluid dynamics modeling with ANSYS Fluent, a team compared three system architectures: standard photovoltaic modules, conventional flat-plate PV/T collectors, and wire-coil-enhanced PV/T units. Simulations employed ten-year average meteorological conditions from Karaj, Iran. The wire coils work by disrupting laminar fluid flow, thinning the thermal boundary layer, and promoting mixing—all passive mechanisms that require no additional energy input.
Results showed that adding a thermal collector raised electrical efficiency 2.9% relative to plain PV, while wire-coil integration pushed that gain to 4.9%. Annual average thermal efficiency improved from baseline figures to 35.7% with coils present. From an economic perspective, converting a PV system to PV/T increased electrical levelized cost of energy (LCOE) from $0.028 to $0.042 per kilowatt-hour. However, when accounting for both heat and electricity output, the combined LCOE dropped to $0.0165/kWh for conventional PV/T and $0.0155/kWh for wire-coil systems—substantially lower than standalone photovoltaics.
Environmental analysis quantified lifecycle CO₂ mitigation. Adding a thermal collector enhanced emission reduction by 118.4% compared to PV alone, while wire coils contributed an additional 7% improvement. This dual benefit—lower operating cost and reduced carbon footprint—positions PV/T systems as practical alternatives for applications requiring both power and heat, such as commercial buildings, industrial facilities, and district heating networks.
The study demonstrates that wire-coil inserts represent a low-cost, passive design modification that delivers measurable gains across technical, economic, and environmental dimensions without introducing operational complexity.
