A study to determine the optimum tilt angle for installing photovoltaic solar panels in Zomba district, Malawi, has been conducted. The study determined the optimum monthly tilt angles of PV solar panels and the seasonal adjustments needed for the panels in order to collect maximum solar radiation throughout the year. In this study, global solar radiation (GSR) on four tilted surfaces was measured. The north-facing surfaces were titled at angles of 0°, 15°, 20°, and 25°. The GSR data was used to determine the daily and monthly optimum tilt angles for the PV panels. The optimum tilt angles were found to be 0° or 25° depending on the time of the year. From October to February, the optimum tilt angle has been determined to be 0° and, from March to September, the optimum tilt angle is observed to be 25°. There are only two seasonal adjustments that are needed for PV solar panels in Zomba district and these should be carried out at the end of February and at the end of September. For fixed solar panels with no seasonal adjustments, the optimum tilt angle for the PV solar panels that are northfacing has been determined to be 25°. 1. Introduction Non-renewable energy sources, such as fossil fuel, have been the major source of energy in many countries, including Malawi. But because of the problems associated with the use of these non renewable energy sources, there is a need for alternative energy sources that are sustainable and nonpolluting. Kalogirou [1] observed that solar energy offers one of the best solutions to the problem of climate change. It also offers the possibility of reducing high demand for grid electricity and shortage of cooking and heating energy in rural and poor-urban households [2]. Madhlopa [3] further observed that Malawi has abundant solar radiation for most of the year. There are several ways in which solar energy is being used, either directly or indirectly [4]. For direct usage, solar energy can be used as thermal energy or indirectly by converting it into electrical energy using photovoltaic systems. For larger, utility-scale applications, solar energy can feed vast photovoltaic (PV) solar panel farms or can be concentrated to vaporize fluids or to run heat engines [5]. Photovoltaic (PV) solar panels are used to convert solar radiation directly into electricity. Among the many renewable energy alternatives, solar energy remains one of the most well-known and adaptable methods for producing heat and electricity [1]. The conversion of solar energy into electricity by the solar panels is affected by, amongst other factors, absorption
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