This paper presents the feasibility and optimization analysis of submersible water pumping system application in East Coast of Peninsular Malaysia. The main objective of this study is to design the optimum sizing of system components through HOMER software ( Hybrid Optimization of Multiple Energy Resources ) to fullfill the requirement of 2.2 kWh/d DC primary load with 1.9 kWp load. The simulation result show the optimal sizing of 1.5 kW photovoltaic system , 12 batteries of 220 Ah with 36 V system voltage and 300 W of converter. This configuration is the most technically feasible to lift a water of 30 liters/min at 70 meters depth.

Natural substances extracted from plants have been gaining attraction as protective agents due to their safety and responsible for multiple biological effects on skins. The present study was to determine the total phenolic and flavonoid contents, Sun Protection Factor (SPF), and antioxidant potential of different solvent extracts of Graptophyllum pictum leaves. The dried powdered leaves were extracted by the cold maceration method, using three different solvents, i.e., methanol, ethanol, and water. The extracted leaves was tested for antioxidant activity using of DPPH (1,1-diphenyl-2-picryl-hydrazyl). Total phenolic content was determined using the Follin-Ciocalteu and for total flavonoid content with used the aluminium chloride. The SPF of all extracts were analyzed by ultraviolet (UV) spectrophotometry. The total phenolic content is the highest in methanol extract (377.61±0.31 µg/ml), and total flavonoid content is the highest in ethanol extract (158.06 ± 0.18 µg/ml). For DPPH free radical scavenging activity, ethanolic extract showed the maximum percentage of inhibition, and for SPF, methanol extract had displayed the highest. The study recommends that methanol is a good solvent for the extraction of sun-protective constituents from G. pictum.

The main challenge for photovoltaic systems is to withstand the high surface and ambient temperatures caused by direct solar radiation, which decreases system efficiency. This research aims to develop a photovoltaic thermal system cooling method using nanofluid SiO2/water with a volume concentration of 0.5-1.5 vol.% and a radiation rate of 450-850W/m2. The working fluid flow rate is between 1.8 and 6 L/min at each radiation rate. SiO2/water 1.5 vol.% under 850W/m2 radiation with a flow rate of 6 L/min produced the best results, with an average overall efficiency of 71.99%, the thermal efficiency of 63.43%, and electrical efficiency of 8.56%. However, the highest electrical energy efficiency was achieved at 650W/m2 with a 9.27% efficiency.