Understanding Cooling Performance

Thermal effusivity — the instant 'cool to the touch' feel

Thermal effusivity (often abbreviated TE, measured in W·s^½/m²·K) describes how quickly a material draws heat away from another surface it contacts — like skin. A high-effusivity material feels noticeably cool the moment you touch it because heat flows rapidly from the warmer body into the cooler material. This is the metric behind the immediate, perceivable cooling sensation consumers associate with premium cooling fabrics and surfaces.

Enthalpy — the sustained cooling reservoir

Enthalpy (measured in J/g) describes how much thermal energy a phase change material can absorb as it transitions from solid to liquid at its activation temperature. A high-enthalpy material acts as a thermal buffer: it continues pulling heat out of the system across a sustained window, smoothing temperature spikes and prolonging the cooling effect well beyond the initial contact.

Why both metrics matter

• Effusivity drives first-touch perception — critical for retail demos, point-of-sale impressions, and short-duration contact applications.
• Enthalpy drives sustained performance — critical for overnight sleep, full-shift wear, packaging, and any scenario requiring continuous thermal regulation.
• The right material strategy often combines both: a high-effusivity surface paired with a high-enthalpy core delivers cooling that is both immediately perceivable and durable.

How Alexium engineers around each metric

• AlexiCool® — engineered for elevated thermal effusivity through patented thermal-conductive additives, delivering an enhanced cool-to-the-touch sensation alongside PCM-based heat absorption.
• BioCool® — engineered for industry-leading enthalpy (>200 J/g), maximizing the size of the sustained cooling reservoir for long-duration applications.
• Both platforms can be specified independently or layered, depending on whether your priority is first-touch perception, sustained regulation, or both.

Specifying the right platform

Our applications team works with brands and manufacturers to translate end-user experience goals — 'cools instantly,' 'stays cool all night,' 'prevents thermal spikes' — into the right combination of effusivity and enthalpy for your construction, substrate, and process. Download the one-pager below for a side-by-side comparison, or contact our team for a tailored recommendation.