Ice storage is currently the dominant cooling energy storage method. To more effectively utilize natural, renewable cooling sources, such as evaporative cooling and sky-radiative cooling, diurnal storage media operated on a daily basis at the temperate range between 10 and 20 degrees C are the most desirable. This paper will present the experimental investigation of microencapsulated paraffin slurry as cooling storage media for building cooling applications. The water slurry of microencapsulated n-hexadecane with a melting temperature of 18 degrees C was cooled to 5 degrees C and heated to 25 degrees C cyclically in a storage tank of 2301, and it was observed that full latent heat storage can only be realized at around 7 degrees C due to supercooling, and the effective cooling storage capacity at the cooling temperature range between 5 and 18 degrees C are obtained, which can be used to realistically estimate cooling storage capacity with various natural cooling schemes. (C) 2010 Elsevier By. All rights reserved.