Low Grade Heat Recovery Patents: Top Companies & Trends 2026
Low Grade Heat Recovery and Absorption Chiller Patents
31.1% of all 845 records sit with just five assignees, but the tenth-ranked filer holds only 22 records — the concentration thins out fast past the leader. Filings peaked at 44 in 2017 and have declined since; the 2021-to-2024 span — the last three years with reasonably complete publication data — shows a 56% drop from 9 to 4. Years after 2024 will fill in as publications catch up, so treat the tail as incomplete rather than as continued decline.
- 1HITACHI LTD94
- 2CARRIER CORP66
- 3SANYO ELECTRIC CO LTD48
- 4YAZAKI CORP28
- 5EBARA CORP27
See the full low grade heat recovery and absorption chillers analysis in Eureka
- The complete ranking, not just the top five
- Every IPC branch with its share of the corpus
- The most-cited records, and where claim space is still thin
Common questions about this landscape
Who holds the most patents in absorption and adsorption chiller technology?
One assignee leads the ranked field with 94 of the 845 records in scope, noticeably ahead of the fifth-ranked assignee at 27. That said, the top 10 combined hold only 44.7% of all records, so no single company or small group controls the field outright. A freedom-to-operate search should still look closely at the leader’s portfolio, but it should not stop there — the remaining 55% is spread across roughly 90 other ranked assignees plus unranked filers.
Is absorption chiller patent filing activity growing or shrinking?
Filing volume peaked in 2017 at 44 records and declined over the following years; the last three-year span with reasonably complete publication data, 2021 to 2024, shows a 56% drop from 9 to 4. Because publication typically lags filing by about 18 months, the 2025 and 2026 figures in any chart will look artificially low and should not be read as continued decline. The honest read is that filing activity has cooled from its 2017 peak, not that the technology has stalled.
What patent classes cover low-grade heat recovery and absorption chiller technology?
The dominant class is F25B, covering refrigeration and heat pumps, which appears on 74.6% of the 845 records in scope. Secondary classes include B01D for separation processes (9.8%), F24F for air conditioning and ventilation integration (8.5%), and F25J for gas liquefaction and separation (6.3%). Because a single patent record can carry several IPC classes, these percentages add up to more than 100% and should not be treated as a strict breakdown of the field.
Disclaimer. This analysis is based on Patsnap Eureka data drawn from a limited snapshot of global patent records and is provided for general information and reference only. Patent data carries inherent limitations — recent filings are under-counted because of publication lag, counts may be on a record or family basis, classification and applicant-name data may contain errors or duplicates, and the underlying search query defines the scope shown — so the analysis may be incomplete or inaccurate and may not reflect the full technology landscape.
Nothing here is an exhaustive prior-art, novelty, freedom-to-operate or validity search, nor does it constitute legal, financial or professional advice, and it should not be relied upon as such. Verify independently and review with qualified patent and legal professionals before acting on it.
Method: Filing trend and technology composition. Derived from a Patsnap search on Low Grade Heat Recovery and Absorption Chillers covering 2015–2026, data cut-off 2026-07-31. Counts reflect published records only and shift as new filings publish. Every share divides by all records in scope. Data: Patsnap Eureka. See the full landscape report.