Design and experimental investigation of an IoT-based integrated PV-thermal solar energy system for RAS applications

Abstract

Intensive aquaculture has grown quickly to meet global food demand, and maintaining water temperature stable is one of its main difficulties. In this project, we designed an integrated temperature control and monitoring (IoT) subsystem for an aquaculture setup intended for isolated, energy-limited environments. Its sensing and control nodes run on a hybrid solar energy collection setup built around a modified photovoltaic panel that also heats the water. This panel works as a photovoltaic/thermal (PV/T) collector, so we obtain a double gain by cooling the PV module to boost its electrical efficiency, and at the same time, we capture the waste heat for warming the aquaculture water in cold weather. The IoT side uses two types of temperature sensors, contact and noncontact, depending on what is being measured, along with microcontrollers and a microprocessor all interconnected through the MQTT protocol for realtime control and monitoring. This preliminary single-day evaluation shows that the solar collector loop heated around 73 l of the heat exchanger water from 30.5 °C to 40.4 °C in 6.37 h, while the insulated tank held a nearly constant temperature over the same 24-hour cycle, without heating or cooling being called for, under the hot ambient conditions of the reported test. Cooling the panel raised its estimated output by about 14%, of which only about 3% is attributable to the change in available sunlight and the remainder to the recovery in conversion efficiency, and the collector used an estimated 42% of the horizontal solar resource once the electrical and thermal gains are taken together. The complete tank-heating process still requires validation under cold and repeated operating conditions. Even so, these results indicate that the prototype offers a practical and low-energy approach to monitoring and controlling water temperature in remote or energy-poor regions.