A numerical analysis of heat and mass transfer inside a reversibly used water cooling tower

In subtropical regions, a desuperheater heat recovery system for service hot-water heating can be applied. However, in colder seasons when building cooling load is reduced, a standard water-cooling tower may be reversibly used to extract free heat from ambient air to make up the reduction of heat source for water heating. Previous related work included developing an analytical method for evaluating the heat and mass transfer characteristics in a reversibly used water-cooling tower (RUWCT), which cannot be used to determine the air and water states at any intermediate horizontal sections along the tower height within an RUWCT. This paper presents a detailed numerical analysis by which the air and water states at any horizontal plane along the tower height within an RUWCT can be determined. The numerical analysis has been partially validated using the experimental data from an installed RUWCT in a hotel building in southern China. The numerical analysis reported in this paper, together with the Analytical Method previously developed, provides a complete method for the analysis of heat and mass transfer characteristics within and at the boundaries of an RUWCT.