(406a) Enhanced Phase Change Materials for Ocean Thermal Gradient Energy Application

Thermal engine based on phase change materials (PCM) has attracted attention in unmanned underwater vehicles (UUVs) because it provides economic and efficient energy storage solutions. The goal here is to develop advanced PCM with enhanced thermal properties to accelerate the heat transfer rate and increase power generation per profile for UUV. Materials with high thermal conductivity were used as additives to enhance the thermal conductivity of paraffin mixtures which was selected as the PCM candidate due to their appropriate melting temperatures (below 18 ^oC) and availability. The dispersion of the additives in PCM was enhanced by modification of the surface with long carbon chain molecules. The thermal conductivity of the modified PCM was measured in liquid and solid states to quantify the enhancement and correlate the relationship with the concentration of the additives in the full operating temperature range. The impact of thermal conductivity and melting temperature of the PCM on the power generation per profile for UUV were evaluated using a COMSOL model.