Solid State Cooling

Most cooling (and many heating) systems rely on the exchange of heat between liquids or on gases that change from liquid to vapour to move heat around. Solid-state cooling works differently. It uses solid materials that heat up or cool down when exposed to magnetic fields, electrical currents, pressure, or mechanical stress. This means that Solid State Cooling (SSC) systems can run silently with no moving parts, be smaller and more flexible in design, require less maintenance and eliminate the need for refrigerants and their related emissions.

Solid-state systems use thermoelectric devices (TEDs) or modules made of semiconductors benefiting from the Peltier effect. When an electric current is passed through these modules, they create a temperature difference, generating heat on one side and cold on the other. By reversing the current, the heating and cooling roles of the module can be reversed. Which means these systems can provide both heating, cooling, and with adaption to HVAC systems also ventilation.

Here are main approaches which are used to achieve solid-state cooling:

• Thermoelectric (Peltier effect), which is already used in small fridges and electronic cooling. Recent material improvements have boosted efficiency by about 70%.
• Elastocaloric, which uses flexible metal alloys that heat and cool when stretched. This is promising but still limited by material wear.
• Magnetocaloric, which uses magnets to drive temperature change and is effective but currently large and expensive.
• Barocaloric, which uses pressure changes, with promising lab results but high-pressure requirements.

Solid-state cooling is already being applied in niche, high-value markets where precision and reliability matter most:

• Medical and laboratory equipment, where quiet, accurate temperature control is vital.
• Electronics and data centres, for localised cooling of chips and components.
• Aerospace and defence, where space and vibration control are critical.

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