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Summary: Efficiency drop due to increase in photovoltaic (PV) module operating temperature creates a huge difference between the projected and actual electricity generated in large power plants. As a solution to this problem Photovoltaic‐Thermal (PV/T) collector, with PV at top and thermal collector at the bottom has been developed. PV/T can cool the PV as well as generate low‐temperature thermal energy. This article presents a comparative experimental study of two newly developed PV/T collector having transparent solar panel with copper tube absorber arranged in rectangular spiral (PV/T‐RS) and horizontal oscillating (PV/T‐HO) configurations. The PV/T collectors are experimentally evaluated under outdoor conditions at Indian Institute of Technology Guwahati. The developed PV/T's are compared in terms of electrical and thermal efficiencies. The PV/T‐RS is found to be better as compared to PV/T‐HO in terms of electrical output, whereas reverse result is reported in case of thermal output. The average electrical and thermal efficiency was found to be 11.2% ± 0.95% and 57.11% ± 2.94% for PV/T‐RS. The calculated average thermal efficiency of PV/T‐HO (63.6% ± 2.94%) is found to be 11.4% more as compared to PV/T‐RS. The overall exergetic efficiency for PV/T‐RS and PV/T‐HO was found to be in the range 11.8%‐16.2% ± 3.18% and 9.7%‐15.25% ± 3.18%, respectively. [ABSTRACT FROM AUTHOR]

Summary: This study has dealt with the synthesis and characterization of biochars produced from three biomasses, viz. water hyacinth (whole plant and its components), yellow oleander, and sugarcane bagasse, and their comparative assessment for potential application in agronomy and energy production. The pyrolysis was carried out in a fixed batch reactor at 350°C and 550°C with a heating rate of 20°Cmin−1. Biochars were characterized for proximate and ultimate (elemental) analysis, and also using standard techniques (SEM, EDX, TGA, BET, XRD, and FTIR). Biochars produced at 550°C from all the feedstock had good properties (carbon content: 39.09‐80.74%, pH: 7.36‐10.42, calorific value: 16.98‐30.18 MJ kg−1, and ash content: 0.89%‐21.78%). Moreover, relatively low atomic ratios (H/C 0.25‐0.47 and O/C 0.15‐1.11) of all biochars indicated their potential as solid fuel. XRD results showed the presence of amorphous and crystalline structures, and minerals like sylivite, quartz, kalsilite, and tridymite in the biochar. Biochar produced from sugarcane bagasse at 550°C possessed the best properties: fixed carbon (77.42%), bulk density (0.13 kg/m3), brunauer–emmett–teller (BET) surface area (17.78 m2/g), pore size (12.86 nm), total pore volume (0.025 cm3/g), calorific value (30.18 MJ kg−1), ash content (1.16%), and moisture content (2.03%). [ABSTRACT FROM AUTHOR]