Therapeutic hypothermia is rapidly becoming an integral part of post-resuscitative care for post-cardiac arrest patients, with cooling increasingly being initiated in the prehospital setting in order to improve patient outcome. However, commercially available devices are not sufficiently portable or do not provide enough cooling power. Additionally, despite the significant impact of thermoregulation on core temperature change during rapid cooling, current mathematical models for thermoregulation have not been validated for hypothermic conditions. In the present study, a novel portable cooling device using adsorption cooling has been proposed, and a prototype was developed to prove that the concept is feasible. Additionally, a geometrically accurate 3D model of an upper leg was developed in order to further understand heat transfer in the human body and to validate thermoregulation models from literature. There was good agreement between simulation results and experimental data at 18°C water immersion, however, significant discrepancy was observed at lower temperature.