US 9,115,913 B1, titled simply Fluid heater, is the United States patent granted to Andrea Rossi for a water or air heater built around a sealed, electrically triggered fuel wafer. It is the most concrete technical disclosure in the E-Cat dossier: unlike the promotional material collected elsewhere, it names a fuel recipe, layer thicknesses and an operating cycle. The patent text describes the heat as coming from a nickel-catalysed exothermic reaction. Its only reference to anything nuclear is background: it mentions fission in conventional power plants as one existing way of heating water. Even so, the claimed features include a radiation shield for the tank.
The patent record
According to the Google Patents record, application US13/420,109 was filed on 14 March 2012, which is also its priority date. The record gives 25 August 2015 as both the grant and publication date, although its legal-events table also carries a "patent grant" status entry dated 5 August 2015. The patent contains 10 claims. Rossi is the sole inventor and LEONARDO Corp the original assignee. The legal events show an assignment from Rossi to Leonardo Corporation of Florida, recorded on 26 June 2015 with an effective date of 13 January 2015, and a reassignment back to Rossi on 30 August 2017. A certificate of correction was issued on 8 March 2016. Small-entity maintenance fees were paid for the fourth year (14 February 2019) and the eighth year (8 February 2023). The record lists the patent as active with an adjusted expiration of 13 November 2033.
The record also flags the patent family as involved in litigation, linking to a case in the Southern District of Florida, number 1:16-cv-21199. The listing does not say who the parties were or how the case ended, and this page draws no conclusion from it.
The patent office classified the invention under F24V30/00, which covers devices that use heat from exothermic chemical reactions other than combustion. That is a filing category, not a finding about how the device works.
What the patent describes
The patent claims an apparatus with three main parts: a tank holding the fluid to be heated, a fuel wafer that holds reagents and a catalyst, and a heat source, such as an electrical resistor, to start the reaction. In the embodiment shown in the drawings, the tank has a lead composite shield, an inlet and outlet on a closed pipe loop, and a door opening onto a receptacle that projects into the water. Fins on the receptacle carry heat into the tank, and the patent suggests a corrosion-resistant metal such as stainless steel. A pump, or the fluid's own pressure, moves the heated fluid to a load such as room radiators. The patent says the fluid can be water or another liquid, or a gas such as air.
How is the fuel actually packaged? As a flat sandwich sealed by welding around every edge. At its core is an electric heating element on insulating mica; on either side sits a fuel section in which powder is held between steel plates, with more mica keeping the wiring electrically separate from the fuel. Typical thicknesses given are 1 mm for the steel and about 0.1 mm for the polymer-coated mica. Overall size, the patent says, does not matter to function, though a wafer roughly 1/3 inch thick and 12 inches square is convenient to handle.
The fuel chemistry
The fuel layer is a mix of nickel, lithium and lithium aluminium hydride (LiAlH4, which the patent abbreviates "LAH"), all as powders. The patent gives one suitable starting mix as 50% nickel, 20% lithium and 30% LAH. It adds that varying the ratio mainly changes the reaction rate and is not critical. It describes the particles as mostly spherical, between 1 nanometre and 100 micrometres across.
According to the patent, nickel acts "as a catalyst for the reaction, and is not itself a reagent". It says other group 10 elements, such as platinum or palladium, could do the same job. The nickel is first treated to make it more porous. The patent's method is to heat the powder so that water trapped in tiny cavities in each particle superheats. The resulting steam pressure blasts the cavities wider and breaks off additional smaller particles.
The document does not identify what the reaction is, and it offers no test data or measurements for it.
The stated operating cycle
Why would a heater whose reaction supposedly keeps itself going need a controller at all? The patent's answer is that the electrical input is only a trigger and an occasional boost. Once started, the reaction is described as self-sustaining, so the power can be cut, but its rate is not steady. A temperature sensor in the tank therefore feeds a controller that decides when to switch the voltage back on. As for how often, the patent states that "after the reaction has generated approximately 6 kilowatt hours of energy", about 1 kilowatt hour of electrical input should be applied to revive it. The wafer's efficiency eventually falls until reviving it is no longer worthwhile; the patent puts its typical life at about 180 days of continuous running before replacement.
The drawings also show other arrangements. The unit can sit downstream of a conventional furnace, which stays off unless the output temperature falls below a threshold. Units can be connected in series for a hotter output or in parallel for greater volume.
What the document does and does not establish
The patent says it "has been found" that about 1 kilowatt hour of electrical input should be applied after roughly 6 kilowatt hours of generated energy. This is a stated reviving schedule, not a measured ratio of total heat out to total electricity in, and the patent gives no overall efficiency or coefficient of performance. The reviving schedule and the 180-day wafer life are asserted without any test data, calorimetry, measurement method or independent check. As Patent as Evidence explains, a grant shows that an application met the patent office's requirements. It does not show that the claimed output is real.
For this dossier, the patent's chemical framing is the main point. Reports about the E-Cat (Energy Catalyzer) attribute its excess heat to a nickel–hydrogen nuclear process involving transmutation (see Nickel–Hydrogen Excess Heat Claim and Low-Energy Nuclear Reaction (LENR)). The patent, by contrast, presents an exothermic reaction catalysed by nickel and was classified as a chemical heat source. It also discloses lithium and LiAlH4 as fuel ingredients, where other dossier material describes the additives as proprietary. On the other hand, the embodiment gives the tank a lead composite shield and the claimed features include a radiation shield. A reader may reasonably wonder why a chemical heater would need either, and this page leaves that tension open.
Connections in the patent literature
Among the nine citations listed is Rossi's earlier application US20110005506A1, Method and apparatus for carrying out nickel and hydrogen exothermal reaction (priority 2008). Later documents that cite this patent include Lenr Cars Sarl's Low energy nuclear thermoelectric system (US9540960B2), two Plasma frequency trigger patents assigned to Ih Ip Holdings Limited, a Brillouin Energy Corp. Heating system and methods patent (US12590732B2), and a 2022 Korean publication by Rossi, KR20220166169A, on an electric energy generator. Being cited shows that later filers took notice of the patent. It does not show that anyone reproduced its results.
Further reading
- E-Cat Claims vs. Evidence: The Dossier's Documents and the Absence of Independent Replication
- Andrea Rossi
Source notes & attribution
- https://patents.google.com/patent/US9115913B1/en