Design and Development of a Low-Cost Phototransistor-Based Pyranometer for Solar Resource Assessment

Pyranometer is a device used to measure solar irradiance that reaches the Earth. It is commonly utilized in solar energy systems, agricultural research, and weather monitoring. The high cost of conventional pyranometers, particularly in developing nations, can prevent their widespread usage. This thesis presents a low-cost phototransistor-based pyranometer that is simple to manufacture using readily available components. The low-cost pyranometer design presented in this thesis provides an affordable and accessible alternative to traditional pyranometers. When light hits the phototransistor, a small electrical voltage is generated. A NodeMCU development board is used to measure the solar irradiance from this voltage by using the conversion factor of calibration of the pyranometer. The performance of the pyranometer was assessed by evaluating real-time data, and the results were analyzed through graphical representation and mathematical calculations. Calibration of the pyranometer was done by using the CM 11 pyranometer, which can be considered a standard device in the process of calibrating pyranometers. The simple design and low price of this pyranometer make it an excellent tool for education and performing experiments, particularly in developing countries like Bangladesh, where the price of conventional pyranometers is expensive.