Thermal Energy Storage Patents: Top Companies & Filing Trends 2026
- 13.5% of the field sits with five companies. 4,044 of 29,879 records in scope belong to the top five assignees, with a long tail of single- and low-filing entrants behind them.
- Filing growth cooled after 2021. Annual filings ran from 1,300 in 2021 to 902 in 2024, a 31% decline over that three-year span, after peaking at 1,310 in 2022.
- Heat-exchange apparatus is the densest single class. F28D covers 11.4% of all records, well ahead of refrigeration, HVAC and solar-collector classes that each sit near 6-7%.
Filing growth compares 2021 (1,300 records) with 2024 (902) — a three-year span. 2024 is the most recent year we treat as complete: publication lags filing by roughly 18 months, so 2025 onwards are still filling in and any growth rate that ends there would understate the field. Top-5 share is the combined record count of the five largest assignees divided by all 29,879 records in scope (CR5), not by the ranked leaders only.
What the thermal energy storage patent record shows
Thermal energy storage spans heat accumulators, working-fluid circuits, phase-change and sensible-heat media, and the control systems that manage charge and discharge cycles. This landscape draws on 29,879 published records filed or published between 2015 and the 2026 data cut-off, indexed against IPC subclasses spanning heat exchange, refrigeration, HVAC, solar collection and combustion control. Filing activity is not evenly spread: a small group of assignees holds a disproportionate share of records, while the majority of the ranked field files only occasionally.
Because publication trails filing by roughly 18 months, the most recent one to two years in any trend chart will always look thinner than they will eventually turn out to be. The reliable read on direction comes from comparing complete years — 2021 against 2024 here — rather than reading the tail as a decline.
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Filing trends and technology composition
Two views of the same 29,879 records: how filing volume has moved year over year, and how the field splits across the IPC subclasses that recur most often in thermal storage disclosures.
Filing trend, 2017-2026
Annual filings rose to a peak of 1,310 in 2022, then eased to 902 by 2024 — a 31% pull-back from the 2021 level of 1,300. Treat 2025 and 2026 figures as provisional; they will revise upward as publication catches up with filing dates.
Technology composition by IPC subclass
F28D (heat-exchange apparatus) leads at 11.4% of all records, ahead of F25B refrigeration and heat pumps at 6.9%, F24F air conditioning and ventilation at 6.6%, F01K steam and thermal power plants at 6.6%, F24S solar heat collectors at 6.0%, G05B control systems at 5.2%, F24D domestic heating at 5.1% and F24J at 4.4%. Because records carry multiple classes, these shares sum to more than 100% of the record total.
Shares are the percentage of the 29,879 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Thermal Energy Storage Patent Landscape with Eureka
This page is one run against one query. Ask Eureka your own question about thermal energy storage patent landscape and every answer comes back with the patent numbers behind it.
Try EurekaA representative filing and the most-cited records
Thermal energy storage plant (US20180106165A1)
Filed by Siemens Gamesa Renewable Energy, this filing describes a thermal energy storage plant with a charging circuit that moves a first working fluid through an electrically powered heating device into a heat accumulator. The accumulator has a hot end and a cold end, storing thermal energy at a first temperature and releasing the working fluid at a lower second temperature through a plurality of internal elements.Published 2018-04-19 — illustrative of the working-fluid-plus-accumulator architecture common across the corpus.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US7187960B2 | Apparatus and method for measuring biologic parameters | 1,332 |
| 2 | US5540681A | Method and system for radiofrequency ablation of tissue | 1,285 |
| 3 | US6131570A | Temperature controlling device for aerosol drug delivery | 1,257 |
| 4 | US20090216910A1 | Computing infrastructure | 1,027 |
| 5 | US9641122B2 | HVAC actuator with automatic end stop recalibration | 957 |
| 6 | US20100324962A1 | Smart building manager | 954 |
| 7 | US20160045841A1 | New and improved system for processing various chemicals and materials | 860 |
| 8 | US20110126848A1 | Electrically heated smoking system with internal or external heater | 779 |
| 9 | US8706914B2 | Computing infrastructure | 692 |
| 10 | US20130306084A1 | Aerosol generating system with means for disabling consumable | 665 |
Citation counts favour older filings simply because they have had longer to accumulate citations within this searched corpus — read them as a signal of influence on the field, not as a ranking of current technical importance.
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Browse MCP servers →What the numbers mean for filing strategy
Three patterns stand out once the records are grouped by assignee, class and geography: concentration at the very top, a technology mix weighted toward heat-exchange hardware, and a receiving-office pattern that tracks the US and Europe first.
The top of the field is narrow, the rest is long
Five companies hold 4,044 of 29,879 records in scope, and the leading assignee alone accounts for 1,422. Beyond the top ten — who together hold 18.6% of records — filing drops off quickly into single-digit counts, which means most of the ranked field is defending a narrow claim set rather than a broad portfolio.
Growth has cooled from its 2022 peak
Filings peaked at 1,310 in 2022 before easing to 902 by 2024, a 31% decline across that window. The comparison excludes 2025-2026 because publication lag means those years are still filling in and would understate current activity if read as a trend.
Heat-exchange hardware is the densest claim space
F28D heat-exchange apparatus covers a larger share of records than any other subclass, ahead of refrigeration, HVAC, steam power and solar-collector classes that each sit in the 5-7% range. Dense claim coverage in F28D signals occupied space, not a settled or mature technology.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to thermal energy storage patent landscape, with the prior art for and against each one.
Who is filing, and where the gaps sit
The ranked leaders span industrial HVAC, automotive, consumer electronics and grid-storage specialists, but recent-year momentum shows most of the largest historical filers pulling back rather than accelerating.
A single assignee holds the largest share
The leading assignee's 1,422 records outpace the fifth-place holder's 603 by more than double, showing a steep drop-off even within the top five rather than a gradual taper.
Recent-year filing is pulling back across most leaders
Several of the historically largest assignees show flat or negative year-on-year momentum in the latest year, including one leader down 82% and another down to zero filings. This is consistent with the broader 2021-2024 decline rather than isolated to one company.
Cross-entity filing is concentrated in a few pairs
Only 10 co-assignee pairs appear in the dataset, and the strongest pair — a corporation and its own European R&D centre — accounts for 35 shared records. The next strongest pairs link an automaker with its component and boiler-industry affiliates.
| Assignee | Recent year | YoY |
|---|---|---|
| Tyco Fire & Security | 8 | -82% |
| Johnson Controls Technology Company | 1 | -50% |
| Philip Morris Products S.A. | 1 | 0% |
| Johnson Controls Tyco IP Holdings LLP | 0 | — |
| Mitsubishi Electric Corporation | 0 | — |
| Malta Inc. | 0 | -100% |
| Toyota Motor Corporation | 0 | -100% |
| Octopus Energy Heating Ltd | 0 | -100% |
Where to take this next
The dataset points to specific questions worth running deeper on rather than closing here.
Trace the F28D claim boundary
Heat-exchange apparatus is the densest single class in the corpus; pulling the actual claim language behind that 11.4% share shows exactly where the occupied ground sits and where it thins out.
Explore F28D filingsWatch the post-2024 filings as they publish
2025 and 2026 records are still arriving under the 18-month publication lag; re-running the trend once those years complete will show whether the 2021-2024 pull-back continues or reverses.
Track filing trendsMap the under-claimed branches
Phase-change encapsulation and molten-salt corrosion control show thinner density than the dominant classes; a freedom-to-operate check there is cheaper before filing volume catches up.
Check white spaceCommon questions on thermal energy storage patents
Within this dataset of 29,879 records, filing is concentrated at the top: the leading assignee holds 1,422 records, and the top five combined hold 4,044, or 13.5% of all records in scope. Beyond the top ten, who together hold 18.6%, the ranking spreads across a long tail of assignees filing far smaller numbers. This pattern is typical of a field with a few large industrial players — HVAC, automotive and consumer-electronics firms among them — surrounded by many occasional filers rather than one dominant monopoly holder.
Filings rose to a peak of 1,310 in 2022, then declined to 902 by 2024, a 31% drop over that three-year span from the 2021 level of 1,300. That said, 2025 and 2026 figures in any dataset should be read cautiously because patent publication typically lags the actual filing date by around 18 months, so the most recent years always look thinner than they eventually will. The safest read on direction compares complete years, which shows a genuine pull-back from the 2022 peak rather than continued acceleration.
The densest single class in this corpus is F28D, heat-exchange apparatus, covering 11.4% of all 29,879 records. Refrigeration and heat pumps (F25B), air conditioning and ventilation (F24F), and steam and thermal power plants (F01K) each cover roughly 6.6-6.9% of records, with solar heat collectors (F24S), control systems (G05B) and domestic heating (F24D) close behind. Because a single record can carry several IPC classes, these shares add up to more than 100% of the record total, which is expected and not a data error.
US20180106165A1, assigned to Siemens Gamesa Renewable Energy and published 2018-04-19, describes a thermal energy storage plant built around a charging circuit that moves a first working fluid through an electrically powered heating device into a heat accumulator. The accumulator has a hot end receiving fluid at a higher temperature and a cold end releasing it at a lower temperature, with internal elements structuring the heat exchange. It is a representative example of the working-fluid-plus-accumulator architecture that recurs across many filings in this corpus, rather than a singular outlier design.
Relative to the dominant heat-exchange and HVAC classes, sub-areas such as phase-change material encapsulation, molten-salt working-fluid corrosion control, and sensor integration at the accumulator's hot and cold ends show thinner filing density in this corpus. Solar-collector-to-storage charging circuits and F24J-linked combustion control logic also sit below the density seen in F28D and F25B. Thinner density signals room to file distinct claims, but it is worth confirming with a fuller freedom-to-operate search before committing R&D spend to any one branch.
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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.