Numerical Analysis of a Closed Thermo-syphon Hot Water Solar System under Steady and Transient Loading Conditions

Solar energy is one of the most important sources of alternative energy. This energy source is inexhaustible and the cleanest of all known energy sources. One of the most important systems which can be used to exploit energy stored in the solar rays is a Thermo-syphon. A thermo-syphon works under the principle of natural convection, in which the working fluid rises, once it heats up, due to reduction in its density. The research regarding the effect of various types of thermal loadings on the performance output of a thermo-syphon is severely restricted, and most of the work available is based on experiments in which the detailed analysis of the complex flow field within the thermo-syphon is extremely difficult to perform. Hence, the present study focuses on the use of advanced Computational Fluid Dynamics (CFD) based techniques to simulate natural convection in a thermo-syphon operating under various loading conditions. The results depict that an increase in the thermal load, for both steady and transient loading conditions, decreases the temperature of the working fluid within thermo-syphon because of loss of thermal energy in the condenser.