Solid State Cooling in HVAC

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.

Leading players in HVAC and advanced materials are actively positioning themselves in the emerging solid-state space. With one collaboration reporting a 70% efficiency improvement using nano-engineered thermoelectric materials which could accelerate the adoption of compact, compressor-free cooling solutions across both electronics and HVAC sectors. Such developments reflect a growing consensus among technology and HVAC leaders: solid-state systems are likely to play a pivotal role in the next generation of refrigerant-free product design.

Whilst Solid-state cooling remains in its early stages, momentum is building, it won’t replace conventional air conditioning overnight, but offers a clear trajectory toward more sustainable and efficient cooling solutions. As advanced materials become more cost-effective and dependable and as regulations continue to phase out harmful refrigerants the commercial potential for solid-state cooling will steadily grow.

This article is based on the BSRIA article "Emerging Trend Spotlight: Solid-State Cooling in HVAC" dated October 2025 and written by Pietro Picca Senior Market Intelligence Analyst at BSRIA.

--BSRIA

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