Thursday 13 March 2025
Scientists have been working on developing better phase change materials (PCMs) for thermal energy storage, and a new study has shed some light on how to improve these materials. PCMs are substances that can store heat or cold as they change from solid to liquid or vice versa. They’re used in everything from air conditioning systems to solar panels, and could potentially be used to stabilize the grid by storing excess energy generated during peak sun hours.
The problem with current PCMs is that they often have limited thermal stability, meaning they can’t withstand high temperatures without breaking down. This limits their usefulness for applications like concentrated solar power, where temperatures can reach as high as 200°C (392°F). To combat this, researchers have been experimenting with new materials and techniques.
One approach has been to use mixtures of salts, which can have higher thermal stability than individual salts. However, these mixtures can be tricky to work with, as they often require precise control over their composition to achieve the desired properties.
The study in question used a combination of differential scanning calorimetry (DSC) and temperature history method (THM) to analyze the thermophysical properties of several salt mixtures. DSC measures the heat flow into or out of a sample as it’s heated or cooled, while THM involves heating and cooling the sample repeatedly to measure its thermal response.
The researchers found that by using glycerin as a reference material in the THM analysis, they could achieve more accurate results than with traditional water-based methods. This is important because PCMs need to be able to withstand high temperatures without breaking down, and glycerin’s higher boiling point makes it a better choice for this type of testing.
The study also looked at the heat capacity of several salt mixtures, which is important because it determines how quickly they can absorb or release heat. The researchers found that some of these mixtures had surprisingly high heat capacities, making them well-suited for use in thermal energy storage applications.
One of the most promising materials tested was a mixture of 54% potassium nitrate and 46% sodium nitrate. This material has a melting point of around 221°C (430°F), which is much higher than many other PCMs on the market. It also has a relatively high heat capacity, making it well-suited for use in concentrated solar power systems.
Cite this article: “Improving Phase Change Materials for Thermal Energy Storage”, The Science Archive, 2025.
Thermal Energy Storage, Phase Change Materials, Pcms, Salt Mixtures, Glycerin, Differential Scanning Calorimetry, Temperature History Method, Heat Capacity, Concentrated Solar Power, High Temperature Stability.
