Water mass flow optimization for hydrosolar roof

Abstract

Cooling towers are classical solutions to remove heat from air-conditioning systems and other industrial facilities. This process is possible due to the energy and mass transfer between flowing air and water. The hydrosolar roof optimised in this paper is able to obtain the same effect substituting the fan of the mechanical draught cooling towers for air flow induced by solar radiation and wind. In a previous work, the drop size of the sprayed water and the pumping pressure necessary to obtain it was studied and the optimal operation point was found to a fixed water mass flow. This work describes the design point optimization procedure taking into account the water mass flow as an essential variable to evaporative systems. In particular, air and water mass flow ratio is one of the most important variable to study the cooling capacity in a cooling tower. Therefore, hydrosolar roof results will be showed as cooling tower results are usually showed. The necessary correlations to performance the optimization procedure were obtained by a hydrosolar roof numerical modelization. The numerical simulation takes into account both evaporative and convective effects and two-dimensional version of the CFD code Fluent was used. In this way, weather variables as solar radiation, wind velocity, dry bulb temperature and wet bulb temperature have been taking into account. Numerical results have been validated with the experimental results obtained previously in a hydrosolar roof prototype.