Abstract : The rapid growth of world economy and population caused a remarkable rise in consumption and demand of energy around the world. As a result of that, all societies, and governments have paid considerable attention to promote energy efficiency through different technologies to reduce energy consumption while fulfilling that demand, by storing the excess energy, and restoring the wasted heat generated during different processes. One of the main energy storage methods is thermal energy storage techniques, which can be classified into three main categories: Sensible heat storage, Thermochemical heat storage, and Latent heat storage. Latent heat storage which depends basically on phase change materials (PCMs), where the thermal energy is stored in the material by changing its phase at almost constant temperature, including Solid-Solid, Solid-Liquid, and Liquid-Gas phase change mediums. Solid-Liquid PCMs are extensively used according to many advantages, and they can be classified into three groups: Organic PCMs, Inorganic PCMs, and Eutectic mixtures. Applications of Solid-Liquid phase change materials include Food preservation equipment, Thermal management of Li-ion batteries, Solar thermal application, Desalination process of seawater by PCM integrated solar stills, PCM micro capsulation technologies in textiles, Cooling of photovoltaic panels, and Cooling of electronic components included in space craft electronics, communication devices, avionics, and power electronics.