TY - JOUR
TI - The combined effect of nanofluid and reflective mirrors on the performance of photovoltaic/thermal solar collector
AU - Ahmed Omer Khalil
AU - Bawa Shaimaa Mohammed
JN - Thermal Science
PY - 2019
VL - 23
IS - 2
SP - 573
EP - 587
PT - Article
AB - A photovoltaic thermal (PV/T) solar collector is a system which is capable of  producing both electricity and thermal energy; however this technology still  needs more studies. In this paper, a mathematical model was presented to  study the performance of a PV/Thermal collector by using the upper and lower  reflectors with the presence of glass cover. Water and nanofluids (AL2O3-H2O)  were used as cooling medium. A computer program was proposed to calculate the  amount of solar radiation reflected on the reflected mirrors and then  absorbed by the hybrid collector and study the effect of Nano-fluid on the  performance of the system. Solar radiation absorbed by the collector can be  increased using the upper and lower reflectors to 1138 W/m2 while it can  reach 950 W/m2 with the upper reflector and 746 W/m2 with the lower  reflector. It was noticed that when using reflective mirrors, the outlet  water temperature increased by 21.7%. Meanwhile, the outlet water temperature  increased by 0.44% when nanofluid was used as a cooling medium. The average  of daily thermal efficiency as a result of using two reflectors without  nanofluid was 62.1%, while the thermal efficiency was 59.735 % without using  any reflector, meaning a positive effect of using reflectors on the thermal  efficiency. The electrical efficiency reduced with the existence of the  reflective mirrors, whereas the daily average of the total electrical  efficiency without the reflective mirror and using the nanofluid was (14.6  %), while with a reflective mirror and using nanofluid, the daily average was  (13.67 %).