Waste-Heat Recovery Patents: Top Companies & Filing Trends 2026
- No single filer dominates. the ranked leader holds 761 records and the top 5 combined account for just 4.6% of all 70,264 records in scope.
- Filing pulled back after its 2023 peak. activity ran 1,031 in 2023 before easing, with 2021-to-2024 filings down 27% on a like-for-like complete-year basis.
- Steam and thermal power plant claims lead the technology mix. F01K carries 5.6% of records, well ahead of separation processes and gas-turbine plant classes.
Filing growth compares 2021 (953 records) with 2024 (700) — 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 70,264 records in scope (CR5), not by the ranked leaders only.
What the waste-heat recovery patent record actually shows
Waste-heat recovery spans steam and thermal power plant design, gas-turbine integration, refrigeration-cycle heat pumps and hydrocarbon-processing retrofits, so the 70,264 records in scope over this window cut across several distinct engineering disciplines rather than one. The search string pairs waste-heat and heat-exchanger terms with working-fluid, thermal-cycle and efficiency-improvement language, which pulls in both dedicated heat-recovery hardware and the broader process plants that host it. Patent families, not raw document counts, are the fairer unit for judging real filing activity, since continuation practice and multi-jurisdiction filing can inflate a single invention into several published documents.
Filing offices split heavily toward the United States, with Europe, the WIPO PCT route and Canada forming the next tier — a pattern consistent with a technology that is filed nationally first and internationalised selectively rather than globally as a default.
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Filing trend and technology composition
Two views of the same 70,264-record dataset: the filing trend by publication year, and the IPC subclasses that carry the most claim density. Because a single record can carry several IPC classes, the composition shares add up to more than 100% of records.
Filing trend: a 2023 peak, then a cooling-off
Filings rose from 976 in 2017 toward a peak of 1,031 in 2023. Comparing complete years, 2021's 953 filings fell to 700 by 2024, a 27% decline over that span. Publication lags filing by roughly 18 months, so 2025 and 2026 figures are still filling in and should not be read as a continuation of that decline.
Technology composition by IPC subclass
F01K (steam and thermal power plants) is the largest single subclass at 5.6% of all records, followed by B01D separation processes at 2.9% and C01B inorganic compounds at 2.6%. F02C gas-turbine plants, F28D heat-exchange apparatus, F02G hot-gas engines, F25B refrigeration and heat pumps, and C10G hydrocarbon refining each sit between 1.7% and 2.5%, showing that claim activity is distributed across plant-level, component-level and process-integration approaches rather than concentrated in one hardware category.
Shares are the percentage of the 70,264 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Waste-Heat Recovery Patent Landscape with Eureka
This page is one run against one query. Ask Eureka your own question about waste-heat recovery patent landscape and every answer comes back with the patent numbers behind it.
Try EurekaA representative filing and the most-cited prior art
Structure for controlling temperature of hot-water supply from a waste heat recovery system
Filed by Kyungdong Navien in 2015, this record covers a control structure for regulating hot-water supply temperature from a waste-heat recovery system, using either a three-way/mixing valve or a heat exchanger inside the hot-water tank, aimed at stable temperature delivery and improved system efficiency during recycling of waste heat.Its claims sit specifically on hot-water-supply temperature control within residential and light-commercial waste-heat recovery, not on the broader heat-exchanger or thermal-cycle categories that dominate the rest of the dataset.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US20160045841A1 | New and improved system for processing various chemicals and materials | 860 |
| 2 | US6232352B1 | Methanol plant retrofit for acetic acid manufacture | 724 |
| 3 | US20110220874A1 | Inorganic Bulk Multijunction Materials and Processes for Preparing the Same | 520 |
| 4 | US20120235579A1 | Methods, apparatus and systems for providing occupancy-based variable lighting | 500 |
| 5 | US20060152085A1 | Power system method and apparatus | 441 |
| 6 | US20030066638A1 | Devices using a medium having a high heat transfer rate | 428 |
| 7 | US5229102A | Catalytic ceramic membrane steam-hydrocarbon reformer | 391 |
| 8 | US6155212A | Method and apparatus for operation of combustion engines | 388 |
| 9 | US5626021A | Variable temperature seat climate control system | 385 |
| 10 | WO2000057935A1 | Method, apparatus and components of dialysis system | 361 |
Citation counts favour older records in any searched corpus; treat them as a signal of influence within the field, not as a ranking of current technical importance.
Each row carries its publication number; clicking a row searches Eureka by that number.
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Browse MCP servers →What the concentration and citation data mean for filing strategy
The ranking, the citation table and the co-assignee pairs each point to a different kind of risk: crowded claim space, influential but ageing prior art, and joint-venture filing patterns worth watching before entering a jurisdiction.
Leadership is thin, not entrenched
The ranked leader holds 761 records and even the tenth-placed assignee holds 292 — a gap wide enough to matter, but a top-5 share of only 4.6% of all records means no single company has locked up the field. That leaves room for a well-drafted claim to stand on its own rather than needing to route around one dominant portfolio.
Post-peak cooling, not a collapse
Filings peaked at 1,031 in 2023 after several years of growth from 976 in 2017. The complete-year comparison from 2021 to 2024 shows a 27% decline, but recent-year assignee-level momentum data shows several leaders still filing, just at a slower pace than their historical peak.
Old chemical-process patents still anchor examiner searches
The most-cited records in this dataset are broader chemical-processing and materials patents rather than dedicated heat-recovery hardware, which suggests examiners in this space frequently reach back to foundational process patents when assessing novelty of new heat-recovery claims.
A handful of tight collaboration pairs
Only 10 co-assignee pairs appear in the dataset, and the strongest pair files together far more often than the others, pointing to a specific joint-venture or subsidiary relationship rather than a broad industry norm of co-filing.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to waste-heat recovery patent landscape, with the prior art for and against each one.
Who is filing, and where the claim space is still open
The ranked leaders come from heavy industry, power generation and automotive OEMs, but momentum has cooled across nearly all of them in the most recent year. The gaps sit in more specific sub-branches than the broad subclass totals reveal.
Heavy industrial OEMs anchor the ranking
The leading assignees are concentrated among power-plant, turbine and heavy-equipment manufacturers rather than component specialists, consistent with waste-heat recovery being filed as part of larger plant and engine programmes rather than as standalone devices.
Even large filers are pulling back
Recent-year momentum shows sharp year-on-year declines at several of the largest historical filers, with one major industrial group down 92% and others down between 50% and 88%. Only one tracked assignee held flat at 0% YoY, none show recent-year growth in the data provided.
Collaboration is narrow and specific
Co-filing is rare and concentrated in a small number of corporate-family or joint-venture pairs rather than being a general industry pattern, which means most competitive intelligence on this field should track individual assignees rather than alliance structures.
| Assignee | Recent year | YoY |
|---|---|---|
| Nuovo Pignone Tecnologie S.r.l. | 5 | 0% |
| General Electric Company | 2 | -92% |
| Saudi Arabian Oil Co. (Saudi Aramco) | 1 | -83% |
| Raytheon Technologies Corporation | 1 | -88% |
| Honda Motor Co., Ltd. | 1 | -50% |
| Mitsubishi Heavy Industries, Ltd. | 0 | — |
| Lummus Technology Inc. | 0 | -100% |
| Scania CV AB | 0 | — |
Where to take this analysis
The figures above establish where filing has concentrated and where it has thinned out. Turning that into a filing or freedom-to-operate decision means drilling into specific claim language.
Check freedom-to-operate in a specific IPC subclass
Composition shares tell you where claim density sits at the subclass level, but a real FTO check needs claim-by-claim comparison within that subclass before drafting.
Explore claims in Eureka →Track a specific assignee's recent filing behaviour
Year-on-year momentum figures here are aggregate; a working file on a single competitor needs its full recent filing list and claim scope.
Run an assignee search in Eureka →Common questions about waste-heat recovery patents
Across the ranked assignee list of 100 companies, the leading filer holds 761 records, with the fifth-ranked assignee at 585 and the tenth at 292. The leaders are concentrated among heavy-industrial equipment makers, power-generation OEMs and automotive manufacturers rather than dedicated heat-recovery component specialists. Even so, the top 5 combined account for only 4.6% of all 70,264 records in scope, so the field is led rather than owned by any single company.
Filing activity rose from 976 records in 2017 to a peak of 1,031 in 2023, then eased to 700 by 2024, a 27% decline over the 2021-to-2024 window using complete-year data. Because publication typically lags filing by around 18 months, the 2025 and 2026 figures in any dataset like this are still incomplete and should not be read as evidence the field is currently falling. The honest read is a post-peak cooling among historically large filers, not a collapse in interest.
F01K, covering steam and thermal power plants, is the largest single IPC subclass at 5.6% of all 70,264 records. B01D separation processes and C01B inorganic compounds follow at 2.9% and 2.6% respectively, with gas-turbine plants, heat-exchange apparatus, hot-gas engines, refrigeration/heat pumps and hydrocarbon refining classes each in the 1.7%-2.5% range. Because a record can carry multiple IPC classes, these shares are not mutually exclusive and add up to more than the total record count.
That record, assigned to Kyungdong Navien and filed in 2015, covers a control structure for regulating hot-water supply temperature from a waste-heat recovery system using either a three-way/mixing valve or an in-tank heat exchanger. Its claim scope is specific to hot-water temperature control in recovery systems rather than to heat exchangers or thermal cycles generally, so it constrains close variants of that valve-based control approach without blocking the wider waste-heat recovery field. Anyone filing in adjacent hot-water control mechanisms should review its claims directly rather than assume broad coverage.
The technology composition data shows several IPC subclasses carrying meaningfully lower filing density than the leading F01K steam-plant category, including refrigeration-cycle heat pump integration, hot-gas external-combustion engine retrofits, compact plate heat-exchanger apparatus and hydrocarbon-refining heat-recovery retrofits. Lower filing density in these branches means claim space is less occupied, not that the underlying technology is unproven. A freedom-to-operate check within the specific subclass is still the right next step before drafting.
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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.