EXPERIMENTAL RESEARCH OF THERMAL PROCESSES IN THE THERMAL STORAGE TANK WITH A PHASE CHANGE MEDIUM

Abstract

Introduction of thermal storage tanks (TST) in facilities that use renewable energy resources represents a good way to increase their energy efficiency. This paper surveys a part of the activities (performed during the realization of the second year of project III 42011 financed by the Ministry of education and science of the Republic of Serbia) on the development of TST whose storage medium melts at the atmospheric pressure, enabling on that way the use of the energy of phase change for energy storage. TST of this type enable more thermal energy storage per volume unit, but also (depending of the working medium) enable higher temperatures of the working medium, which is necessary in the co-generated facilities. For the purpose of the experimental research of thermal and flow processes in TST in the Laboratory for thermal engineering and energy of the Vinča Institute a prototype of TST was designed and made. It has a cylindrical shape, with the working volume of 77 dm3. The working material is heated by 2.4 kW electric heater positioned along the TST axes, and is cooled by the air which circulates around the tank. The measurement of temperature inside the tank was performed by 16 thermocouples, 4 along the tanks height and 4 along the tanks radius. For the purpose of this work paraffin as a working medium was used. Measurements were performed for non-stationary as well as for stationary working regimes. As a result, an extensive set of experimental data was obtained, which, in the later work on the project, will serve in the numerical study, as a basis for the developing a numerical model, to verify its results and, if necessary, to correct the model.