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Metrological framework for passive radiative cooling technologies

Short Name: PaRaMetriC, Project Number: 21GRD03
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Rooftop air system on skyscraper in Hong Kong

Developing metrological frameworks to standardise new passive cooling materials and test them under real-world conditions.

It is estimated that 10 % of global greenhouse gas emissions are related to cooling buildings and environments. Passive Radiative Cooling (PRC) materials – an emerging technology that can cool to sub-ambient temperatures, even in direct sunlight – could be an efficient alternative to conventional systems, saving up to 80 % of cooling-related electricity. PRC materials radiate infrared at wavelengths the atmosphere is transparent to, allowing it to pass through into space, without absorbing light back from the sun. The previous EMPIR project EMIRIM worked on improving hemispherical emissivity measurement techniques to determine the energy efficiency of reflective insulation products. This generated a reference setup that can be used by the industry to classify products based on performance. However, the complex structures of PRC materials mean that current industry standards and references are not applicable. Additionally, a lack of standardisation and guidance for testing PRC properties, along with no standardised methods for testing real-world performance, have limited uptake.


This project will develop a metrological framework to classify and compare PRC materials, assessing and validating appropriate benchmark materials and laboratory testing methods. It will also focus on characterising the properties of PRC materials and develop modelling methods, setting standards for quality control and allowing long-term effectiveness to be evaluated. The project will also create protocols and best-practice guides for in-field testing and set up long-term tests across several sites to assess material performance under a variety of real-world conditions. This project will help drive innovation in PRC technology, producing more energy-efficient cooling to meet rising needs. The standardised methods developed by the project will allow informed decisions to be made by both citizens and industry, and will overall reduce reliance on fossil fuels, in turn reducing the human impact on climate change.


Project website
Other Participants
Agencia Estatal Consejo Superior de Investigaciones Cientificas - IETcc-CSIC (Spain)
Almeco S.p.A. (Italy)
Center for Applied Energy Research e.V. (Germany)
Comitato termotecnico italiano energia e ambiente CTI (Italy)
Consiglio Nazionale delle Ricerche (Italy)
Cooling Photonics Sociedad Limitada (Spain)
Ethnikó kai Kapodistriakó Panepistímio Athinón (Greece)
Forschungsinstitut für Wärmeschutz e. V. München (Germany)
Politecnico di Torino (Italy)


Metrology Partnership
Green Deal
in progress
Total EU contribution (in M €)