[!] Introduce (PDRC) Passive Daytime Radiative Cooling membrane | SOLUTION by CTNMS®
- Randy W.
- Jul 17
- 5 min read
In the daily operations of industrial and commercial facilities, "heat" has always been a hidden source of pressure on equipment reliability and energy costs. From outdoor electrical enclosures to HVAC outdoor units, from telecommunication base stations to refrigerated logistics containers—any equipment exposed to direct sunlight over the long term will continue to accumulate heat, gradually eroding performance, shortening service life, and translating into substantial energy and maintenance expenses. For decades, the industry's primary response to heat has been active cooling—air conditioners, fans, and water-cooling systems—using electrical power to carry heat away. However, under the dual pressure of climate change and rising energy costs, the limitations of this approach have become increasingly visible. Passive Daytime Radiative Cooling (PDRC) represents a fundamentally different way of thinking: without relying on any electrical input, it uses pure optical principles to send heat directly away from the equipment, away from the ground, away from the atmosphere—ultimately radiating it to the -270°C vacuum of outer space. As a mature technology, PDRC serves as a complementary technology to active cooling, enabling a more complete overall thermal management strategy.
PDRC is a passive cooling technology that uses pure optical principles to radiate heat directly to the -270°C vacuum of outer space. The entire process requires no electricity, no refrigerant, no fans, no compressors, and no moving parts. Nighttime radiative cooling has long been familiar to us all—the frost that forms on a car roof under a clear night sky is the result of radiative cooling bringing the roof temperature below the surrounding air. Under direct sunlight, however, ordinary materials absorb solar radiation far faster than they can radiate heat back to space, which is why daytime cooling has long been considered physically difficult to achieve. PDRC materials, through precise optical engineering, make daytime sub-ambient cooling possible—this is precisely why PDRC stands as the value proposition of a new generation of passive thermal management technology.
WHY- The Three Thermal Risks That PDRC Addresses in Outdoor Equipment
Active cooling in outdoor equipment carries three underlying pain points: energy consumption, CO₂ emissions, and maintenance complexity. Traditional white paints and reflective coatings can block a portion of incoming solar radiation, but they can only "reflect"—they cannot "actively radiate heat away." Any heat that has already entered the equipment continues to accumulate internally, and cooling effectiveness plateaus at ambient temperature. This is precisely why the industry needs a new technical pathway: a passive cooling technology that can bring equipment temperatures below ambient, even under direct sunlight.
Equipment Failure：Heat is the enemy of every electronic component. Sustained high temperatures accelerate insulation degradation, electrolyte deterioration in capacitors, semiconductor interface fatigue, and thermal stress accumulation at solder joints—leading to unstable operation, intermittent failures, and premature end-of-life. These problems rarely manifest immediately; rather, they accumulate over thousands of service hours into reliability risks that can no longer be ignored.
Energy Expense：Faced with continuously accumulating heat loads, most facilities respond by intensifying active cooling operations—lowering AC setpoints, increasing fan speeds, extending refrigeration runtimes—to maintain target temperatures for equipment and interior spaces. Every one of these extra operations translates directly into electricity costs. Especially during summer peak hours, the active cooling energy curve tends to climb in sync with peak electricity pricing, making thermal management a substantial operational line item for many industries.
CO₂ Emissions：The other side of the energy expense coin is carbon output. To counter the two risks above, most industries choose to add active cooling systems. Yet active cooling itself is powered by electricity, directly pushing up energy consumption and carbon emissions. In today's environment of net-zero commitments, the contradiction between this path and sustainability targets has become increasingly difficult to reconcile.
HOW- The Fundamental Difference Between PDRC and Traditional Cool White Paint / Reflective Coatings
Traditional reflective coatings can only "block the sun." PDRC can simultaneously "block the sun" AND "send absorbed heat back out."
This is the fundamental breakthrough of PDRC over existing passive thermal management materials. Traditional white paints and reflective coatings have cooling capacity that plateaus at ambient—no matter how high the reflectance, the material temperature will ultimately reach thermal equilibrium with the surrounding air and cannot drop lower.
PDRC materials, by contrast, possess the capability of active radiative heat rejection, continuously radiating the material's own heat outward toward outer space, ultimately driving equipment surface temperatures below the ambient air temperature.
WHAT- PDRC 能為現有熱管理策略帶來什麼 價值
Warehousing facilities, shipping containers, tents, and temporary structures are all environments where structural constraints or cost considerations often prevent the use of high-performance insulation materials. In these spaces, surface temperatures during daytime can reach 100°C on metal-sheet exteriors, with internal temperatures often exceeding 40°C—directly affecting worker safety, product storage quality, and refrigerated logistics energy efficiency.
Because PDRC materials come in flexible film form, they can be adhered, sewn, or heat-welded onto virtually any non-flat or non-rigid structure. This makes PDRC a practically deployable passive cooling solution for exactly these types of environments, functioning as a front-end load-reduction tool for downstream active cooling systems.
The surface temperature of an air-conditioner outdoor unit under direct sunlight can reach 35–50°C, which directly increases the thermal load on the compressor and reduces the overall system's coefficient of performance.
When PDRC material is applied to high-temperature surfaces such as the top of the outdoor unit, it enables the active cooling system to operate under more favorable thermal conditions, allowing the compressor to deliver the same cooling effect at a lower working temperature—making the entire AC system run more efficiently.
For HVAC integrators and air-conditioning manufacturers, PDRC represents a complementary technology that delivers additional energy-saving value to end customers.
Any technology capable of reducing overall energy demand directly supports an enterprise's carbon-neutrality roadmap. As a zero-energy, maintenance-free passive technology, PDRC can lower the workload of downstream cooling systems—without adding any operating cost—leading to reductions in both total energy consumption and carbon emissions.
Beyond that, PDRC releases heat directly to outer space rather than exhausting it into the surrounding environment, meaning it does not aggravate ground-level heat accumulation. This also makes PDRC a positive contributor to mitigating the urban heat island effect.
By keeping equipment surfaces and interiors close to or even below ambient temperature, PDRC materials can meaningfully extend the service life of critical components—directly lowering the operational costs associated with maintenance frequency and replacement cycles.
PDRC gives the industry a new tool—one that reduces heat accumulation at the source—positioned alongside, not against, existing active cooling and traditional passive insulation solutions. This technology does not rely on electricity, produces no waste heat, requires virtually no maintenance, and can operate in concert with existing systems. It works by exploiting the transparency of Earth's atmosphere at specific wavelengths to send thermal energy directly to the -270°C vacuum of outer space.
Field-validated across a wide range of applications—electrical enclosures, HVAC outdoor units, containers, telecommunications equipment, building roofs, and more—PDRC offers a new pathway that complements existing active cooling and passive insulation systems. For industries that have long been under pressure from thermal management costs, PDRC deserves serious evaluation as a strategic component of the overall thermal management portfolio.
CTNMS® Teams based in Brisbane and HQ at Taipei is proud to officially add SPACECOOL™ into our product LINEUP, SPACECOOL is one of the most representative industrialized products in the PDRC field and has got some remarkable achievement
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