Development of an enthalpy-based index to assess climatic potential for ventilative cooling of buildings: An Australian example

Ventilative Cooling is a promising technique to improve the energy efficiency of buildings through reduced need for mechanical cooling to maintain thermal comfort. To assess the feasibility of Ventilative Cooling in a specific location, it is useful for designers to be able to evaluate the climate potential for cooling. This paper describes a new and enhanced version of the Climatic Cooling Potential (CCP) method, which is a simplified method to evaluate the climate potential for passive cooling that does not require detailed knowledge of the building characteristics. The proposed Enthalpy Climatic Cooling Potential (CCPh) integrates humidity into the climate evaluation, using the enthalpy difference between indoors and outdoors, instead of the temperature difference. It accounts for latent heat, providing a better estimate of locations where the use of outside air will be beneficial from an energy perspective. The methods were compared by mapping the Ventilative Cooling potential for the Australian climate, using weather data from 391 weather stations across Australia. Results showed that most of the highly populated cities in the south of Australia have a climate suitable for Ventilative Cooling. This is true even in the summer period, although the area where the climate is beneficial is significantly larger during the shoulder seasons and winter. The analysis showed that using the CCP index, rather than the new CCPh index, can lead to an under-estimation of the cooling potential during dry winters and an over-estimation during humid summers, due to the contribution of the latent heat.