21GRD03 PaRaMetriC

Metrological framework for passive radiative cooling technologies

A Joint Research Project within the European Partnership on Metrology Programme

The project 21GRD03 PaRaMetriC received funding from the European Partnership on Metrology, co-financed by the European Union's Horizon Europe Research and Innovation Programme and from the Participating States.

Project overview

Cooling systems account for nearly 20% of electricity consumption and 10% of greenhouse gas emissions, globally. With demand for cooling expected to grow tenfold by 2050, and the increasing frequency of extreme heat waves, improving the efficiency of cooling systems plays a critical role in addressing the global climate challenge. Passive Radiative Cooling (PRC) materials that can dissipate heat as infrared radiation have recently emerged. This project aims to develop a comprehensive metrological framework, including standardised performance indicators (i.e. figures of merit) and testing protocols, to enable the comparable evaluation of their cooling performance on-site and determination of the potential energy savings that could derive from the deployment of such technologies.

PaRaMetriC essentials

identify figures of merit and define protocols for their reproducible measurement
develop and validate models for the performance of passive radiative cooling materials
perform accurate characterization of the thermophysical and spectral properties of PRC materials
develop setups and protocols for on-site testing of PRC materials

The European Partnership on Metrology

In 2020, following on from EMRP and EMPIR, EURAMET proposed the European Partnership on Metrology to the European Commission (EC). In November 2021, the European Partnership on Metrology was approved and the regulation was published in the Official Journal.

The Partnership is co-funded by the Member States and the EU (under Horizon Europe) with an expected budget of over 700 million euro. Impacts expected for the Partnership include supporting a wide range of policies, commercial interests and advancement of key European challenges. It aims to break new ground by contributing to the development of self-sustaining, coordinated metrology infrastructures, able to continue joint research and innovation after 2030. The Metrology Partnership will create a sustainable and effective system for metrology at a European level that ensures Europe has a world-class metrology system that:

Provides metrology solutions, fundamental metrological reference data and methods, offering fit-for-purpose solutions supporting and stimulating European innovation and responding to societal challenges
Supports and enables effective design and implementation of regulation and standards that underpin public policies that address societal challenges

What's the goal of PaRaMetriC project?

The overall goal of this project is to establish a metrological framework for comparable performance assessments of passive radiative cooling technologies.

The specific objectives are:

To develop the conceptual framework for comparable performance assessments of passive radiative cooling technologies.
To develop and validate numerical models to correlate the cooling performance of PRC materials with the thermal and optical properties of their components, and thus to establish their specifications and associated tolerances.
To develop accurate and traceable approaches for determining the thermophysical properties and thermal conductivity of PRC materials, and for converting measured radiometric quantities into a usable form for heat balance calculations.
To develop setups and protocols for on-site testing of PRC materials, with a target uncertainty below 10 % for the figures of merit.
To facilitate the take up of the technology and measurement infrastructure developed in the project.

What will be the project impact?

The overall goal of this project is to establish a metrological framework for comparable performance assessments of passive radiative cooling technologies.

The specific objectives are:

To develop the conceptual framework for comparable performance assessments of passive radiative cooling technologies.
To develop and validate numerical models to correlate the cooling performance of PRC materials with the thermal and optical properties of their components, and thus to establish their specifications and associated tolerances.
To develop accurate and traceable approaches for determining the thermophysical properties and thermal conductivity of PRC materials, and for converting measured radiometric quantities into a usable form for heat balance calculations.
To develop setups and protocols for on-site testing of PRC materials, with a target uncertainty below 10 % for the figures of merit.
To facilitate the take up of the technology and measurement infrastructure developed in the project.

Expected ouctomes from the project
1. New awareness of the cooling potential associated with PRC materials in the different EU climatic regions.
2. More accurate and reproducible prediction of the expected performance of PRC materials developed by the end user companies.
3. More accurate and reproducible measurement of the actual cooling performance exerted on-site by different PRC materials.
4. More reliable testing of newly proposed PRC materials by the research community and industry based on a harmonized set of figures of merit, testing equipment, and benchmark materials.
5. Development of laboratory capabilities for the performance assessments of PRC materials.
Expected broader impacts
1. Scientific impact: New insights on the relative impact of parameters influencing the performance of PRC coatings. Better knowledge of how particular PRC materials dissipate energy, thus more focused development of new materials.
2. Economic impact: Development of a new market for PRC coatings; Energy savings for households and industrial processes with intense/continuous cooling needs. New job opportunities for renovating roofs and installing passive cooling appliances. Development of the industrial capability to develop and produce passive cooling materials in EU.
3. Societal impact: Lower energy needs for cooling, lower use of water for cooling, increased albedo for urban areas to curb global warming, better thermal comfort in urban areas and households, lower health impacts during heat waves.