Abstract

This study focuses on the analysis of the efficiency and the energy performance of a solar water heating (SWH) plant located in the North of Chile, characterized by an instantaneous global solar radiation reaching around 1000 W/m2. The methodology combined experimental measurements in an indirect active solar system with systematic variations in operating parameters, including the evaluation of different flow rates in both the primary and secondary circuits, a comparative analysis of storage system volumes (100 L vs. 200 L) and an assessment of domestic hot water (DHW) consumption management. Precise temperature and flow rate measurements were used to determine performance indicators such as collector efficiency, charging efficiency, and overall plant efficiency. The experimental results reveal that the higher flow rates translate into greater efficiency, reaching a 72% with a flow rate of the 0.63 m3/h compared to the 46% obtained with a flow rate of the 0.35 m3/h. Also, under similar operating conditions, the larger capacity tank (200 L) reaches a lower maximum temperature during the charging (60 degrees C vs. 75 degrees C for the tank of 100 L). However, despite the lower temperature reached, the largest capacity tank (200 L) manages to recover 55% more of DHW. This analysis highlights the importance of considering the efficiency, the storage capacity, and the consumption management to optimize SWH systems in environments with high solar radiation, such as Northern Chile. Furthermore, the exploration of innovative technologies, such as the use of phase change materials (PCM), is suggested to further improve the efficiency of the thermal storage system.