High-Temperature Phase Change Material (PCM) Selection for Concentrating Solar Power Tower Applications

With current concerns about the environmental impact of greenhouse gas emissions, reducing our reliance on fossil fuels has become an ever-growing necessity. A thermal energy storage system that utilizes phase change materials (PCMs) in the form of molten salts, coupled with a concentrating solar power tower plant, is proposed as an effective means of achieving highly efficient and cost competitive power generation on par with traditional fossil fuel-based power. In this study, a set of five selection criteria are applied to a wide range of salt mixtures to determine the best candidates for use as PCMs. The selection criteria include the salt mixture's melting temperature, latent heat, thermal conductivity, material safety, and cost. A shortlist of 20 salt candidates is made, and differential scanning calorimetry experiments are performed on them to verify the thermal properties of these candidates. A final list of eight salts is then selected as the best PCMs for use in a working temperature range between 500 and 800 degrees C.