No abstract

Photovoltaic systems when integrated into a building structure can satisfy the world’s energy requirements at a competitive cost by providing onsite electrical and thermal energies for domestic appliances. The energy yield of the photovoltaic system is affected by the intensity of the solar radiation, wind speed, tilt angle, orientation, geographical location, etc. This paper presents an optimisation model of the tilt angle and orientation of a photovoltaic thermal system. A methodology has been developed to optimize the tilted angle of the roof for higher exergy output taking into account the intensity of solar radiation, wind speed, geographical location, cost of cleaning dust, etc. For a system installed in the city of Douala, Cameroon, it is recommended that the PV should be inclined at an angle between 10° and 20° south-facing for economical output. The cost per unit of electricity between the tilt inclination angles from 0° to 20° with south orientation is USD 0.04 per kWh. The cost of electricity loss due to a 20° tilt inclination angle can be compensated with the labour cost and work required for cleaning the photovoltaic thermal (PVT) system of the horizontal roof. The system installed over an effective area of 8 m2 is capable of producing annual net exergy of 2195.81 kWh/year at an efficiency of 11.8%.

Food losses in the developing country are thought to be 50% of the fruits and vegetables grown and 25% of harvested food grain. Food preservation can reduce wastage of a harvest surplus, allow storage for food shortages, and in some cases facilitate export to high-value markets. Drying is one of the oldest methods of food preservation. Drying makes produce lighter, smaller, and less likely to spoil and helps to minimize the moisture content in coffee beans as high moisture content during storage is certain to ruin the taste and appearance of coffee. This work presents the results of an experimental study of forced convection drying of coffee cherries in a modified Icaro solar dryer. The study aims to validate the numerical models developed for further research. The experimental tests envisaged also aim to determine the mass loss curves of the product by fixing or calculating its initial mass (1 kg), its initial water content (70%), the ambient temperature, the drying airflow (0.02 m 3 •s −1 to 0.09 m 3 •s −1 ) and the exchange coefficients. The influence of these aerothermal parameters on the drying time of a most commercialized coffee variety (Robusta) was studied. Finally, the results revealed an increase in the efficiency of the heat transfer air and a reduction in the water content of the coffee cherry from 70% to 9.87%, after 30.2 hours.