Estudo numérico da estratificação térmica em um reservatório de água do tipo multitanque

Abstract

The utilization of solar energy for water heating represents a significant strategy for harnessing renewable energy. In this context, the efficient use of a water thermal reservoir becomes necessary due to the intermittent availability of solar energy throughout the 24-hour cycle. Studies indicate that thermal reservoirs with a vertical configuration exhibit better efficiency compared to the typical horizontal ones. However, vertical reservoirs may require more vertical space (height), which can be problematic during the installation of these tanks in urban environments or areas with spatial restrictions. This work conducted a numerical study of thermal reservoirs in a multi-tank configuration, where the reservoir is lower, however maintaining the ideal proportion of a vertical tank. The obtained results indicate that the multi-tank reservoir behaves similarly to a vertical reservoir with the same water volume. In the conducted study, the multi-tank reservoir exhibited effective thermal stratification, raising the water temperature to an average of 57.5°C within a 4-hour period for a water volume of 780 liters. It was also observed that the manner in which hot water enters the reservoir influences the thermal stratification behavior and, consequently, the water heating time.