Performance of the rhombus storage solar collector: Experimental assessment

This study introduces and evaluates a novel design of an integrated solar collector, termed the Rhombus storage solar collector. This novel design consists of a cube whose upper side is split in two directions at 45° as an inclined angle to form the absorber surface of 0.52 m2 absorbent area and a total storage volume of 210 L. The major reasons for using this type of collector are their high efficiency and their ability to replace the traditional tanks used in Iraqi houses and developing countries. This innovative design has low costs and high efficiency because it reduces losses by removing connecting pipes. In addition, it is easy to manufacture and is made up of materials that are widely available on the market. This study is based on the maximum useful efficiency curve (MUE), and due to its large thermal mass, it cannot achieve steady-state conditions. This system is evaluated experimentally under various load conditions. The first case is the no-load condition, the second case is the intermittent condition where 50 L of hot water is withdrawn at 2 p.m., and the third case is the continuous load condition of 0.5 L/min. The system demonstrated excellent performance, particularly in low ambient temperatures. The system also showed promising efficiency levels across different load conditions. •A new design for integrated water heaters has been presented.•The system's maximum efficiency was 55 % for the continuous load in December.•The maximum water temperature difference was 13.1 °C in December.•Climatic and operating conditions clearly affect the performance of the new design.