A phase-change material (PCM) —also known as a latent heat storage (LHS) material—changes its state of matter at a specific phase-change temperature, typically from solid to liquid and vice versa.
During melting or solidification, the material can store or release large amounts of energy, allowing it to be used for cooling or heating. The most common applications are ice packs and heating pads. Other examples of use include the catering industry, the construction industry, the automotive industry, and the apparel industry. Well-known PCMs include water and sodium acetate. The latter is used, for example, in the heat pads mentioned above.
In the example shown below, the analysis of the thermal conductivity of two salt hydrates is shown. At room temperature, both PCMs were liquid.
The liquids were poured into a beaker, which was placed in a temperature-controlled water bath. For the measurement, the THB/B/Metal sensor was suspended in the sample.
The measurement points were -20 °C, -10 °C, 0 °C, +10 °C, 20 °C (room temperature), and +30 °C. The measurement was therefore started while the material was in its solid state. At each temperature level, three measurement points were recorded and averaged.
The thermal conductivity of Sample A increases slightly as it is heated to 0 °C, while Sample B shows a slight decrease. Both samples transition from a solid to a liquid state in the temperature range from 0 °C to 10 °C, which is also clearly evident from the decrease in thermal conductivity.
As the temperature increases, the thermal conductivity of both samples rises slightly. In general, Sample B exhibits higher thermal conductivity than Sample A.
