TechNote 27 Phase Change Materials  

Phase change materials (PCMs) are materials that are capable of absorbing and releasing thermal energy when they undergo a phase change from solid to liquid and from liquid to solid. When a PCM solidifies, it releases energy in the form of latent heat at a relatively constant temperature. Conversely, when such a material melts, it absorbs heat from the environment. PCMs exhibit a thermal mass effect, repeating the phase changes as ambient temperatures fluctuate, making them ideal for a variety of everyday applications in certain environments that require temperature control.