Analysis on the cooling and soaking-up performance of wet porous wall for building

Abstract

The porous ceramic pipes with high water soaking-up ability have been combined for passive evaporative cooling wall. The cooling can be supplied due to the occurrence of heat and moisture transfer between the drying air and the outside surfaces of wet porous pipes when the airflow passes through the combining wall, and the lost water is provided by capillary force in the wet porous media, thus, the passive evaporative cooling continues. In the combining wall, the effects of the arrangement of wet porous ceramic pipes in staggered array or in parallel array, the number of pipe rows and the space between the adjacent pipes, as well as the weather conditions on the cooling were investigated. The Darcy law for unsaturated porous media, the momentum balance of a liquid and J(s) function were employed to analyze the water soaking-up performance in the wet porous pipe. The simulations agree with the test results. Besides, more cooling can be supplied from the wet porous ceramic pipes filled with wet sand than that without wet sand in the tests when the airflow passes through the wet porous ceramic. All results provide some guidance for the promotion and application of the passive evaporative porous wall.