Novel Theoretical Approach on Exergy and Energy Performance Assessment of Cylindrical Solar Water Heater

Abstract

In this paper, a novel theoretical analysis is carried out for evaluating the thermal performance, exergy efficiency, and energy efficiency for a typical cylindrical solar water heater under given operating conditions. In this detailed mathematical modeling, a cylindrical coil tube in the shape of spiral rings, serves as a collector to the incident solar energy on the cylinder wall. The energy balance equations for both the fluid and tube have been established separately. The physical parameters that govern the system are identified. The governing differential equations have been solved for various values of the parameters. Because it is difficult to determine these parameters through experiments, the nondimensional theoretical approach has been applied in this research. Finally, the influences of these parameters on exergy and energy efficiency, which are the most significant factors in the design of a cylindrical solar water heater, are investigated. The results of this theoretical analysis are in good agreement with the experimental measurements noted in the previous literature. The energy efficiency and exergy efficiency of the heater will be above 50 and 2%, respectively, after optimizing the key parameters.