Performance Analysis of a Novel Photovoltaic Thermal PVT Double Pass Solar Air Heater with Cylindrical PCM Capsules using CFD

Photovoltaic Thermal Double Pass Solar Air Heater (PVT-DPSAH) with Phase Change Material (PCM) capsules in the bottom channel is a promising design for enhancing the system performance. The PVT-DPSAH comprises a glass cover, absorber plate photovoltaic (PV), PCM capsules, and back plate. The current study uses COMSOL Multiphysics software to perform a Computational Fluid Dynamics (CFD) analysis of a novel PVT-DPSAH with vertical cylindrical PCM capsules in the second channel. To solve the differential equations in the 3D computational domain, the Finite Element Method (FEM) is employed. This study uses the high Reynolds (Re) number and κ-ε turbulent flow model with enhanced wall functions. The impact of varying solar irradiance levels (500-800 W/m2 ) on the performance of PVT-DPSAH, with mass flow rate (ṁ) ranging from 0.011 kg/s to 0.065 kg/s, is investigated. The optimum mass flow rate was found to be 0.037 kg/s at solar irradiances ranging from 500 W/m2 to 800 W/m2 , with average thermal efficiencies, electrical efficiencies, and fluid output temperatures of 60.7% to 63.4%, 11.25% to 11.02% and 42.96 ºC to 49.54 ºC, respectively. PVT collector's maximum combined efficiency was 84.12% at solar irradiance of 800 W/m2 with the mass flow rate, ṁ of 0.065 kg/s. This study identified RT-47 paraffin-waxPCM as the best option for the PVT-DPSAH based on the PCM's thermal distribution and melting temperature

Solar–Biogas Microgrid: A Strategy for the Sustainable Development of Rural Communities in Pakistan

Access to uninterrupted power is not a luxury but a basic need. Rural communities living far from the national grid, particularly those in the southern region of Pakistan’s Khyber Pakhtunkhwa province, have limited access to a reliable power supply. In order to provide sustainable electricity, small-scale off-grid renewable energy systems are increasingly used for rural electrification. These systems are commonly known as stand-alone home systems or community micro-grids. This paper proposes an off-grid solar–biogas micro-grid for rural communities in the Lakki Marwat district of Khyber Pakhtunkhwa, Pakistan. The area is mainly dependent upon income from the agricultural and livestock sectors. HOMER was used to simulate the electric power system, while RET-Screen was used to analyze the economics of the system. The optimized system’s results demonstrate that the most economically and technically possible system, which produces 515 kWh and 338.50 m3 biogas daily, is made up of a 30-kW photovoltaic system coupled with a 37-kW biomass hybrid system, a 64-kWh battery storage capacity, and a 20-kW invertor. The system will meet the cooking and power needs of 900 individuals who reside in 100 homes. In addition to household users, the system will provide fixed-priced electricity to productive buildings, and free electricity to community buildings. The system will generate 1300 kg of organic fertilizer each day, which will be sold to local farmers for 50% less than what it would cost on the open market. The proposed approach is techno-economically viable based on the payback period and internal rate of return