A Critical Review of Phase Change Materials for Cold Thermal Energy Storage Applications: Conventional Materials and Bio-Based AlternativesIf you are interested in products related to the research phase in this field, please contact for further inquiries.
Modern cold chains are critical to global food security but come with significant environmental costs. The refrigeration sector consumes immense amounts of electricity—up to 281 TWh annually—resulting in approximately 261 million tonnes of CO2 emissions. Of these, 60% are indirect emissions from electricity, while 22% come from refrigerant leakage, and another 18% from diesel use. Power production alone contributes to 42.2% of global GHG emissions, highlighting the urgent need to reduce cold storage's dependence on fossil-fuel-derived energy.
Despite widespread refrigeration deployment, food waste persists. Over 1.05 billion tonnes of food are wasted annually, with a major share attributed to spoilage during storage and transport. This juxtaposition—technological advancement and persistent inefficiency—demands a new approach to cold storage.
Fig 1. (a) Electricity production by source between 1985 and 2022. (b) Distribution of electricity production by sources for the year 2022. (c) Greenhouse emissions for different sectors between 2019 and 2022. (d) Greenhouse emissions for different sectors for the year 2022. (Ouaouja Z., et al., 2025)
Phase Change Materials operate by absorbing or releasing latent heat during their phase transitions. Unlike traditional thermal storage that relies on sensible heat, PCMs undergo a physical transformation—typically solid-to-liquid or vice versa—storing or releasing large amounts of thermal energy at near-constant temperatures.
The total energy storage capacity of PCMs is calculated as: QPCM = Qs(l) + QL + Qs(s)
This equation includes sensible energy in the liquid (Qs(l)) and solid states (Qs(s)), and latent energy (QL). The latent heat makes PCMs especially valuable for cold thermal energy storage (CTES) because it stabilizes temperature with minimal energy loss.
PCMs protect food quality by reducing ice crystal formation, minimizing drip loss, and maintaining relative humidity. For example:
Emissions Reduction
PCM integration in European refrigeration systems could reduce CO₂ emissions by 15.6–75.4 kt annually. In cold chain transport, emissions can drop by 78.5%, with operational cost savings of over 91%.
Energy Cost Management
By storing cooling during off-peak electricity pricing periods, PCM-equipped systems offer both financial and load-balancing advantages, especially when coupled with solar or off-grid power sources.
Fatty Acids and Esters
Derived from vegetable and animal oils, esters like ε-caprolactone and α-tricaprin melt between -54°C and -1.5°C and offer moderate latent heat capacities (36–121.7 J/g).
Edible and Non-Edible Oils
Soy, canola, and corn oils show promise, particularly in eutectic formulations with water. For instance, 10% soy oil in water lowers the melting point to -8°C and cuts supercooling by 6 K.
Agricultural and Food Waste
Secondary olive oil, coffee waste oil, and date seed oil provide sub-zero PCTs with latent heats ranging from 50–105 J/g. These materials offer circular economy benefits while valorizing agricultural residues.
Animal-Derived Fats
Fish oils such as salmon and Pollock exhibit extremely low melting points (-70°C to -35°C), suitable for ultra-low temperature logistics, though their latent heat values are modest.
Amino Acids and Polyols
Glycine-water mixtures demonstrate latent heat capacities of up to 291.15 J/g and good thermal cycling stability. Polyols like glycerol and sorbitol, when mixed with water, show tunable freezing points between 0°C and -23°C.
Image Analysis
The scatter plots in the literature visualize the melting temperature vs. the latent heat of various bio-based materials. Eutectic mixtures cluster in sub-zero regions with practical heat capacities, reinforcing their suitability for CTES.
| Research Area | Key Objective |
|---|---|
| Performance Testing | Broaden CTES application trials in commercial cold chains. |
| Thermal Optimization | Enhance latent heat, fine-tune PCT, improve conductivity. |
| Advanced Encapsulation | Develop nano/micro techniques for stability and efficiency. |
| Hybrid Materials | Combine bio-based and inorganic elements for synergy. |
| Lifecycle Analysis | Assess emissions, biodegradability, and resource impact. |
Phase Change Materials—particularly bio-based variants—represent a transformative opportunity for the cold chain industry. They enable energy savings, improve temperature regulation, reduce spoilage, and offer a clear pathway to sustainable refrigeration. As food security and climate mitigation converge into a shared priority, the integration of PCM technology stands poised to redefine how the world preserves, transports, and consumes perishable goods. The next frontier of cold storage is not more power—it's smarter materials.
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Reference
This article is for research use only and cannot be used for any clinical purposes.
