The PCM based heat source and heat sink devices can be effectively used for various heating and cooling applications and can store and release heat in the form of latent heat. This latent heat can be utilized for maintaining body temperature within comfort range of 33 ± 2°C. The present work focuses on developing a 2-D numerical model to evaluate the performance of PCM cool pack configuration in terms of the evolution of average skin temperature with respect to time. The numerical model is first validated with a 1-D semi-analytical for a simple PCM pack configuration. Once the model is validated, the next level of studies involves the comparison of performance analysis for different PCMs with more realistic cooling pack configuration. Optimal thermal conductivity (which can be engineered by introducing PCM-Graphite composites) is also predicted for different PCMs in order to obtain thermal comfort for a prolonged duration of 3 hrs. The studies do not include the perspiration model; however, incorporation of the skin layer within the model domain took the approach closer to the real condition. © 2018 by the authors of the abstracts.