Method and apparatus to produce thermal energy storage (TES) components

Details

Patent WIPO link: WO2019012074

Developed by: The EU, represented by European Commission

Publication date: 17.01.2019

Countries covered: European Unitary Patent, China, India

Licensing terms: Negotiable royalties, upfront fees, and technical support 

Contact: JRC-TechTransferec [dot] europa [dot] eu (JRC-TechTransfer[at]ec[dot]europa[dot]eu) 

Why energy storage in building materials matters

Unlike conventional insulation, which merely slows heat transfer, TES absorbs, stores, and releases latent heat at specific temperatures. When embedded into structural materials, TES enables buildings to buffer thermal loads internally, shifting heating and cooling demands away from peak hours, improving energy performance and occupant comfort.

TESA (Thermal Energy Storage Aggregates) offer an elegant integration strategy:

• Embedded directly in concrete, they transform structural elements (e.g. floors, walls) into distributed energy storage systems
• They operate without controls, energy input, or maintenance, ensuring passive operation
• They are especially effective in climates with large diurnal temperature variations or buildings with intermittent occupancy

In regulatory and market terms, TESA directly supports:

• Net-zero energy building (NZEB) requirements, by reducing HVAC energy use
• Peak shaving and load shifting strategies in smart grids
• EPBD (Energy Performance of Building Directive) and EU Green Deal targets, through passive demand-side energy optimization

Compared to mechanical or electrical storage, passive TES requires no additional infrastructure, making it uniquely scalable across both new construction and retrofitting applications.

Short technical description of the invention

The patented process enables the production of porous mineral aggregates embedded with phase change materials (PCMs), suitable for direct use in cement-based products. Unlike conventional PCM integration techniques, which rely on surface coating or fragile microencapsulation, this method ensures deep infiltration and long-term retention of PCM within the aggregate structure.

The process is carried out in a sequence of thermal and pressure-regulated steps, as illustrated below

Key advantages/ unique selling points:

• High latent heat capacity

Achieves PCM loading levels of up to 278 kg/m³ of concrete, exceeding performance limits of conventional encapsulation or surface coating approaches.

• Multistage impregnation protocol

A precisely controlled sequence of vacuum soaking, overpressure injection, and isothermal entrapment ensures deep PCM penetration and stable retention within aggregate pore networks.

• Leakage prevention without encapsulation

Final flushing and surface sealing with cementitious or inorganic polymer coatings eliminate surface PCM and create a barrier to leakage across thermal cycles.

• Structural performance compatibility

Designed for direct integration into lightweight or structural concrete formulations, maintaining compressive strength suitable for load-bearing and precast applications. This makes it uniquely suited for cases where both high thermal storage capacity and structural integrity are required.

• Versatile PCM compatibility

Supports a broad range of bio-based or paraffinic PCMs (e.g., lauric acid, glycerol, paraffins), tunable to target climatic conditions and building use profiles.

• Passive operation with zero energy input

TESA enhances thermal mass and provides non-mechanical energy storage — no need for sensors, controls, or maintenance systems.

• Manufacturing scalability

Process is adaptable from bench-scale to industrial batching, with standard components (vacuum chamber, heating/cooling system, air compressor).

Technology readiness level: 5

The technology has been validated in a relevant laboratory environment using industrially available materials and equipment. The process has been applied to lightweight expanded clay aggregates impregnated with fatty acid-based PCMs (e.g., Lauric Acid), followed by integration into standard cementitious formulations.

Performance validation includes:

• Latent heat storage measurements confirming high PCM retention
• Thermal cycling tests showing stable entrapment with no leakage
• Mechanical testing of resulting concrete showing compressive strengths ≥15 MPa, compatible with structural and prefabricated elements
• Repeatability across multiple production batches using pilot-scale setup

The next steps toward TRL 6–7 involve:

• Process upscaling and adaptation to industrial batch environments
• Long-term monitoring under real-use thermal loading conditions
• Regulatory and material certification for commercial concrete applications

Competitive landscape

Thermal energy storage in construction materials is a growing field, but most existing PCM integration strategies are constrained by low storage capacity, leakage issues, or incompatibility with standard concrete processes.

This invention addresses all three limitations by using a vacuum + overpressure impregnation protocol that achieves high PCM loading, mechanical stability, and process scalability without requiring costly encapsulation.

Market potential

Market Size & Growth

The patented TESA technology responds directly to urgent and growing needs in the global building materials and energy efficiency markets. Its passive thermal storage function aligns with both performance-driven construction and policy-driven climate targets.

1. Building Materials Market

• The global green building materials market was valued at $450 billion in 2023, projected to exceed $1.3 trillion by 2030.
• The precast concrete sector, where TESA integration is straightforward, represents over $150 billion globally, with high penetration in infrastructure and modular construction
• Lightweight aggregate concrete, already used for thermal and acoustic performance, is an ideal carrier for PCM enhancement, enabling premium product differentiation

2. Regulatory and Policy Drivers

TESA directly supports energy efficiency policies at national and EU levels, including:

• The EU Renovation Wave and revised Energy Performance of Buildings Directive (EPBD)
  • Building stock decarbonization goals, targeting 35 million building renovations by 2030
  • Nearly zero-energy building (NZEB) requirements and passive building certifications (e.g., LEED, BREEAM)

Addressable Applications

• Precast panels, blocks, and façade systems with embedded thermal storage
• Floor slabs and ceiling elements for load shifting and peak shaving
• Modular retrofit panels for schools, offices, and public housing
• Shelters and off-grid dwellings in hot/arid climates

In all cases, TESA provides a material-integrated energy function, reducing operational energy demand without increasing system complexity.

Ideal licensee profile

The technical expertise in materials science, thermodynamics and process engineering, and the necessary manufacturing infrastructure (e.g., vacuum-capable impregnation chamber, PCM melting unit, vacuum system, compressed air supply, and slurry/spray coating station). 

What JRC offers

The European Commission’s Joint Research Centre (JRC) may provide technical support and collaboration to licensees, including, but not limited to: training and capacity building to support the development of the licensee’s technical expertise and infrastructure, troubleshooting analysis, collaboration on R&D, etc. 

For more information, contact the JRC Technology Transfer Team: JRC-TechTransferec [dot] europa [dot] eu (JRC-TechTransfer[at]ec[dot]europa[dot]eu).