Experimental validation of a numerical model for ventilated wall cavity with spray evaporative cooling systems for hot and dry climates

Abstract

This paper describes an experimental set-up used to validate predictions from a numerical model for ventilated wall cavity with spray evaporative cooling systems. The validation analysis results have indicated that the numerical model, developed and described in a companion paper, can accurately predict the outlet air temperatures and relative humidity levels achieved by a ventilated wall cavity with a spray evaporative cooling system utilized to air condition buildings in hot and dry climates. Air velocity predictions of the ventilated cavity have been also verified against results obtained from a detailed CFD analysis. Moreover, the experimental testing results indicate that the ventilated wall cavity with an evaporative cooling with 5μm spray droplets can significantly reduce outdoor air temperatures. Specifically, the system was able to reduce air temperature from 45°C to 25.5°C. Moreover, the results of a parametric analysis obtained using the validated numerical solution suggest that there is a significant reduction potential in heat transfer through cavity walls while providing acceptable supply air temperature capable of maintaining indoor thermal comfort. In addition, the parametric analysis has evaluated the effect of climatic conditions (temperature and humidity) on the required distances for spray droplets to fully evaporate. The presented results could help in designing effective and energy efficient ventilated wall cavity with spray evaporative cooling systems to condition buildings in hot and dry climates.