The capric–lauric acid and pentadecane combination as phase change material for cooling applications Maria Natalia R. Dimaano a , Takayuki Watanabe b, * a Research Center for the Natural Sciences, University of Santo Tomas, Espa~ na, Manila 1008, Philippines b Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro-ku, Tokyo 152-8550, Japan Received 13 June 2001; accepted 17 September 2001 Abstract The mixture of 65 mol% capric acid and 35 mol% lauric acid (C–L acid) is a potential latent heat storage material. However, its melting temperature of 18:0 °C is quite high for low-temperature thermal energy storage. Addition of pentadecane, with a melting point of 9:9 °C, is proposed. The thermal characteristics of the combination of the C–L acid with pentadecane (CL:P) in different volume ratio are investigated employing the DSC analysis. The actual thermal performance of each CL:P combination is further de- termined from their radial and axial temperature distribution employing a fabricated thermal storage capsule. The 90:10 CL:P combination manifests an improvement in the melting characteristic of the C–L acid. Ó 2002 Elsevier Science Ltd. All rights reserved. Keywords: Low temperature; Thermal energy storage; Capric–lauric (C–L) acid; Phase change material; Pentadecane 1. Introduction A phase change material (PCM) is able to absorb or release large quantities of latent heat at a fairly constant temperature during its phase transition. The search for PCMs has attracted great interest for both heating and cooling systems since they are considered more environmental friendly materials. This concern resulted from the depletion of the stratospheric ozone layer due to the use of refrigerants in air conditioning and refrigeration processes. As alternatives to the present materials for cooling, the PCMs have considerably higher heat storage capacities. Thus, Applied Thermal Engineering 22 (2002) 365–377 www.elsevier.com/locate/apthermeng * Corresponding author. Tel./fax: +81-3-5734-3058. E-mail address: watanabe@nr.titech.ac.jp (T. Watanabe). 1359-4311/02/$ - see front matter Ó 2002 Elsevier Science Ltd. All rights reserved. PII:S1359-4311(01)00095-3