Phase-Change Thermal Storage Refrigerant Patents: Trends & Gaps 2026
- Filing peaked in 2017 at 25 families and has since drifted down to single digits by the 2022 midpoint, suggesting the core mechanical approaches were staked out early rather than being an actively expanding frontier.
- Heat-exchange apparatus (F28D) dominates with 62 of 205 families, more than double the next largest class, while refrigeration-specific subclasses F25B and F25D each sit at 32 — the practical cold-chain hardware is comparatively under-claimed next to generic heat exchange.
- The most-cited prior art is thermoelectric, not PCM-refrigerant the five top-cited records are thermoelectric energy storage systems, meaning influence in this corpus traces back to a related but distinct storage mechanism rather than to today's cold-chain PCM filings.
What this landscape covers
Phase-change thermal storage refrigerant patents cover materials and hardware that use latent heat storage to hold cold temperature for later release — typically inside refrigeration units, cold chain logistics containers, or hybrid thermal-power systems. The search spans 205 patent families filed between 2015 and mid-2026, capturing filings across heat exchange, refrigeration, wind power thermal buffering, and pressure-vessel gas storage where PCM cold storage overlaps with adjacent equipment classes.
Because publication lags filing by roughly 18 months, the apparent falloff after 2022 is partly a reporting artefact — but the decline from the 2017 peak of 25 families is steep enough that it likely reflects a genuine slowdown in new filing activity, not just missing recent data.
Filing trend and technology composition
Two views of the same 205-family dataset: how filing activity has moved year over year, and which equipment classes carry the claim density.
A 2017 peak followed by a steady decline
Filings ran at 25 in 2017 and dropped to 8 by the 2022 midpoint, with the trend continuing downward toward 2026 — a pattern consistent with an early wave of foundational filings rather than an emerging technology still building momentum.
Heat exchange leads, refrigeration hardware trails
F28D (heat-exchange apparatus) accounts for 62 of 205 families, well ahead of F01K (thermal power plants, 39) and the tied pair F25B/F25D (refrigeration and cooling, 32 each). Wind motors (F03D, 22), conveying/material handling (B65G, 21), general materials (C09K, 21) and pressure vessels (F17C, 20) round out the composition, showing this technology sits at the intersection of several equipment domains rather than inside a single dedicated refrigeration class.
Shares are the percentage of the 205 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Phase-Change Thermal Storage Refrigerant with Eureka
This page is one run against one query. Ask Eureka your own question about phase-change thermal storage refrigerant and every answer comes back with the patent numbers behind it.
Try EurekaThe most-cited prior art
Portable device for cold chain storage (US20170290741A1)
A portable cold chain storage container built around an inner cylinder holding phase change material in thermal communication with a coaxial storage region, with evaporative coils embedded directly in the PCM to manage the cooling cycle.Filed by VCC Technology Inc., published 2017-10-12 — illustrates the coaxial-cylinder, embedded-coil construction that recurs across cold-chain PCM container filings.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US20110100611A1 | Thermoelectric energy storage system and method for storing thermoelectric energy | 137 |
| 2 | US20140060051A1 | Thermoelectric energy storage system | 120 |
| 3 | US20040211182A1 | Low cost heat engine which may be powered by heat from a phase change thermal storage material | 90 |
| 4 | US20100101621A1 | Solar powered generating apparatus and methods | 89 |
| 5 | EP2532843A1 | Thermoelectric energy storage system with an evaporative ice storage arrangement and method for storing therm… | 83 |
| 6 | US20210325069A1 | Integrated community energy and harvesting system | 78 |
| 7 | EP2400120A1 | Thermoelectric energy storage system | 77 |
| 8 | WO2011161094A2 | Thermoelectric energy storage system | 57 |
| 9 | WO2015153607A1 | Thermally regulated system | 54 |
| 10 | US20120318475A1 | Building Energy System | 51 |
Citation counts reflect influence within this searched corpus and skew toward older filings; treat them as a marker of foundational status, not current commercial relevance.
Each row carries its publication number; clicking a row searches Eureka by that number.
Put your own technology through the same analysis
Eureka on the web
When you want the answer in the next five minutes.
The agent works the prompt against patents and technical literature, citing every source.
Run your analysis now →MCP server & REST API
When it has to run inside your own pipeline.
Patent search, landscape analysis and assignee resolution as MCP tools. Drop them into any agent framework, or call REST directly.
Browse MCP servers →What the numbers mean for a filing decision
Three observations that shape where a new filing would land relative to existing claim density.
The peak has passed
Filing activity fell from a 2017 high of 25 families to 8 by the 2022 midpoint, and the trend continues down toward 2026. New entrants are filing into a field where the foundational mechanical concepts were already claimed in the mid-2010s.
Heat exchange carries the claim density
F28D (heat-exchange apparatus) holds nearly a third of all families, more than F01K, F25B and F25D combined at the next tier. A filing framed purely as generic heat-exchange hardware faces the densest prior art in the set.
Influence traces back to thermoelectric storage
The five most-cited records in this corpus, led by a thermoelectric energy storage system cited 137 times, are thermoelectric rather than refrigerant-PCM specific. Citation weight in this space currently sits with an adjacent mechanism, not with cold-chain PCM hardware itself.
US and PCT dominate the office split
United States filings (61) lead the receiving-office count, with WIPO/PCT (36) and EPO (27) next, and India (18), Japan (9) and Australia (7) forming a smaller tail — a filer aiming for broad coverage would prioritise the US and PCT routes first.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to phase-change thermal storage refrigerant, with the prior art for and against each one.
Who is active, and where the field is thin
Co-assignee activity is concentrated in a small cluster of pairings, and recent-year filing has gone quiet across the named assignees tracked here.
One cluster drives most joint filing
The strongest co-assignee pairing in the dataset appears 7 times, with two further pairings involving the same lead organisation at 5 each. Co-filing in this space is concentrated around a single research entity rather than distributed across many partnerships.
Named assignees show no latest-year activity
Every assignee tracked for recent-year momentum in this dataset shows zero filings in the latest year. Combined with the declining trend since 2017, this points to a field where activity has cooled rather than shifted quietly between competitors.
A long tail behind the lead cluster
All 205 published records map to distinct families in the assignee ranking, indicating limited continuation-heavy filing by any single player and a broad base of comparatively light, single- or few-filing entrants.
| Assignee | Recent year | YoY |
|---|---|---|
| Heidrustuo Co., Ltd. | 0 | — |
| Ebo Research Co., Ltd. | 0 | — |
| Bright Energy Storage Technology LLC | 0 | — |
| Tuoqitai LLC | 0 | — |
| Innovation Energy LLC | 0 | — |
| Esmushierji Co., Ltd. | 0 | — |
| SOLVCOR TECHNOLOGIES LLC | 0 | -100% |
| MERCANGOEZ MEHMET | 0 | — |
Where to take this analysis
The dataset points to a mature but narrowing filing field. Two directions make sense depending on whether the goal is defensive clearance or new filing strategy.
Map claim boundaries in F28D before filing
With 62 of 205 families sitting in heat-exchange apparatus, a freedom-to-operate check against that class specifically — rather than the corpus as a whole — will surface the densest overlap fastest.
Explore F28D prior art in EurekaTest white space in refrigeration-specific hardware
F25B and F25D combined sit well below F28D despite being the more direct cold-chain classes; a claim drafted around refrigeration-specific PCM integration may face thinner prior art than a generic heat-exchange framing.
Run a white space search in EurekaCommon questions on this landscape
In this dataset, it is a filing that combines phase change material or latent heat storage terminology with cold-side application terms such as cold thermal storage, refrigeration PCM, or cold chain storage. That definition pulls in filings across heat-exchange apparatus, refrigeration and cooling equipment, and several adjacent classes like wind turbine thermal buffering and pressure vessel gas storage, because PCM cold storage functions as a component inside those broader systems. It does not require the filing to be exclusively about refrigeration — many of the 205 families are hardware or materials patents where cold-chain PCM storage is one claimed use among several.
The trend data shows 25 families in 2017 falling to 8 by the 2022 midpoint, with the decline continuing toward 2026. This pattern is typical of a field where the foundational mechanical concepts — coaxial PCM cylinders, embedded evaporative coils, hybrid thermal-power configurations — were staked out in an early wave, after which new filers face denser prior art and fewer open mechanical approaches. Publication lag of roughly 18 months means the very last one or two years understate true filing activity, but the multi-year decline predating that lag is likely real.
F28D, heat-exchange apparatus, leads with 62 of the 205 families in this dataset — more than F01K (thermal power plants, 39) and the tied F25B and F25D refrigeration classes (32 each) combined at the next tier. This means that a large share of claim density in phase-change cold storage sits in generic heat-exchange hardware rather than in refrigeration-specific equipment, which is a useful distinction when scoping a freedom-to-operate search.
Not directly. The five most-cited records in this corpus, topped by a thermoelectric energy storage system cited 137 times, describe thermoelectric energy storage systems and solar-powered generating apparatus rather than cold-chain refrigerant PCM specifically. This means citation-based influence in the searched corpus currently sits with an adjacent thermal storage mechanism, and a practitioner should not assume the highest-cited documents represent the state of the art for refrigerant-specific PCM claims.
The IPC composition points to refrigeration-specific hardware (F25B, F25D) and materials-focused classes (C09K) as comparatively thinner than heat-exchange apparatus, despite being closer to the actual cold-chain use case. Co-assignee data also shows collaboration concentrated around one lead research cluster, leaving most of the 205-family base as single or few-filing entrants — a sign that broader collaborative or cross-class filings, such as PCM-refrigerant integration in material handling or pressure vessel systems, remain comparatively open.
Research Phase-Change Thermal Storage Refrigerant in depth with Eureka
Go past this page: query the whole phase-change thermal storage refrigerant corpus yourself, in your own scope.
Every answer comes back with patent numbers you can open.
Disclaimer. This page is generated from Patsnap Eureka data drawn from a limited snapshot of global patent and scientific-literature records, and is provided for general information and reference only.
Patent data carries inherent limitations: recent filings (typically the most recent 18–24 months) are under-counted due to standard publication lag; counts may be reported at either a patent-family or a patent-record basis and are not always directly comparable; classification, applicant-name, and citation data may contain errors, duplicates, or omissions; and the underlying search query defines and constrains the scope shown. As a result, the analysis may be incomplete or inaccurate and may not reflect the full technology landscape.
Nothing on this page constitutes an exhaustive prior-art, novelty, freedom-to-operate, or validity search, nor does it constitute legal, financial, investment, or professional advice, and it should not be relied upon as such. Any patent, commercial, or strategic decision should be verified independently and reviewed with qualified patent, legal, and domain professionals. Patsnap makes no warranties, express or implied, as to the accuracy, completeness, or fitness for any particular purpose of the information presented.
Machine translation. Assignee and organisation names originally recorded in Chinese, Japanese or Korean have been rendered into English by an AI translation step so that the tables stay readable. These renderings are best-effort and may not match a company’s registered English name; the original name is what the underlying patent record carries, and it is what any Eureka query launched from this page uses.