ORIGINAL PAPER
Enhancement of a spiral-tube PV/T collector using nanofluid under hot climatic conditions: experimental study
1
Northern Technical University, Iraq
Submission date: 2025-10-09
Final revision date: 2025-12-05
Acceptance date: 2025-12-08
Publication date: 2026-09-25
Polityka Energetyczna – Energy Policy Journal 2026;29(3):59-80
KEYWORDS
TOPICS
ABSTRACT
This study experimentally investigates the performance of a spiral-tube photovoltaic/thermal (PV/T) collector integrated with single-crystal silicon PV modules and cooled using Al2O3/water nanofluid. Field trials were carried out in Kirkuk (Iraq) in March 2025 under operating conditions. A 0.5 wt% Al2O3 nanofluid was used as the working fluid, and its performance was compared to that of flat-plate PV panels under air-cooling conditions and modern water-cooled photovoltaic thermal (PV/T) configurations. 13:00, the nanofluid-cooled collector managed to maintain the PV cell at a minimum temperature of ∼29°C, whereas the water-cooled and air-cooled panels were heated up to about 35°C and 60°C, respectively. Meanwhile, electrical efficiency at this time was 13.4% for the nanofluid-cooled PV/T, 12.6% for the water-block system, and 11.8% for the conventional PV module. The thermal efficiency of the nanofluid PV/T system was approximately 13%, while for water it was 12%. Note also that the net effectiveness was able to reach ~15.1% in the case of the nanofluid system and 14.5% for the water-cooled system. The results indicate that the nanofluid cooling effectively reduces PV cell temperature rise and thereby provides improved electrical, thermal, and overall performance in midday hot situations. In contrast to previous research under moderate weather and on flat plate PV/T systems, the current study experimentally illustrates the feasibility of reliable operation of a nanofluid-cooled spiral-tube PV/T collector in Iraq’s intense heat.
FUNDING
This research was not funded by any grant.
CONFLICT OF INTEREST
The Authors have no conflicts of interest to declare.
METADATA IN OTHER LANGUAGES:
Polish
Poprawa wydajności kolektora PV/T z rurami spiralnymi dzięki zastosowaniu nanofluidu w gorącym klimacie: badania eksperymentalne
PV/T, kolektor z rurami spiralnymi, nanofluid Al2O3, wydajność chłodnicza PV
W niniejszym badaniu eksperymentalnie zbadano wydajność kolektora fotowoltaiczno-termicznego (PV/T) z rurą spiralną, zintegrowanego z modułami fotowoltaicznymi z krzemu monokrystalicznego i chłodzonego za pomocą nanofluidu Al2O3/woda. Testy terenowe przeprowadzono w Kirkuku (Irak) w marcu 2025 r. w warunkach eksploatacyjnych. Jako płyn roboczy zastosowano nanofluid zawierający 0,5% mas. Al2O3, a jego wydajność porównano z wydajnością płaskich paneli fotowoltaicznych w warunkach chłodzenia powietrzem oraz nowoczesnych konfiguracji fotowoltaiczno-termicznych (PV/T) chłodzonych wodą. O godz. 13:00 kolektor chłodzony nanofluidem zdołał utrzymać ogniwo fotowoltaiczne w temperaturze minimalnej wynoszącej ∼29°C, podczas gdy panele chłodzone wodą i powietrzem nagrzały się odpowiednio do około 35°C i 60°C. Tymczasem sprawność elektryczna w tym momencie wynosiła 13,4% dla systemu PV/T chłodzonego nanofluidem, 12,6% dla systemu z blokiem wodnym oraz 11,8% dla konwencjonalnego modułu fotowoltaicznego. Sprawność cieplna systemu PV/T z nanofluidem wynosiła około 13%, podczas gdy dla systemu wodnego wynosiła 12%. Należy również zauważyć, że sprawność netto osiągnęła ~15,1% w przypadku systemu z nanofluidem oraz 14,5% dla systemu chłodzonego wodą. Wyniki wskazują, że chłodzenie nanofluidem skutecznie ogranicza wzrost temperatury ogniw fotowoltaicznych, zapewniając tym samym lepszą wydajność elektryczną, termiczną i ogólną w warunkach upałów w południe. W odróżnieniu od wcześniejszych badań przeprowadzonych w umiarkowanych warunkach pogodowych i dotyczących płaskich kolektorów PV/T niniejsze badanie eksperymentalnie wykazuje możliwość niezawodnej pracy kolektora PV/T z rurami spiralnymi, chłodzonego nanofluidem, w warunkach intensywnego upału panującego w Iraku.
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