Electrohydrodynamic heater

Abstract

There is disclosed a full or partial electrohydrodynamic heater (100) arranged to heat a fluid in a first circuit, the fluid comprising a heating fluid or tap water. The heater (100) comprises: a first electroheating element (108) arranged to heat the fluid in the first circuit; and a DC power source (120) arranged to supply power to the first heating element at least in part. The DC power source has a capacity of at least 1 kWh, and optionally at least 5 kWh.

Description

Technical Field

[0001] The present invention relates to an electric heater for a fluid heating system. Specifically but not exclusively, the present invention relates to an electric boiler for a wet heating system or an electric furnace for an air heating system, both of which are applicable to heating a fluid (e.g., via a radiator) or heated tap water or both for heating a space. Background Art

[0002] Gas boilers can provide a wet heating solution to meet hot water and heating needs. For example, a domestic gas boiler typically supplies hot water to heating radiators within a heating system and also provides hot water on demand to faucets (e.g., for drinking, cleaning, washing). The two supplies (heating and faucet) are kept separate because the heating water may get dirty as it passes through the radiator circuit, while the tap water must be clean. Combi boilers are popular because they provide all these functions in a sealed high-pressure environment within a single boiler housing and have a relatively small physical footprint. Other types of boilers with separate tanks or cylinders are also used.

[0003] Gas boilers burn fossil fuels. Therefore, electric boilers are now emerging as an environmentally friendly alternative. Electric boilers will convey water through electric heating elements.

[0004] Electric combi boilers use a technology similar to that of an electric kettle. The electric boiler is connected to the main power supply and supplies cold water from the main pipe. When a hot water request is received (e.g., when a hot water faucet is opened or heating is turned on), the heating element within the electric boiler heats up and transfers this heat to the cold water. Then, the heated water is pumped to the required faucet or radiator.

[0005] Storage electric boilers include a hot water tank (either an internal tank or an external tank within the unit). This enables heating and storing water when energy costs are low (e.g., overnight) for subsequent use when energy costs are high (e.g., the next day). Such systems take up more space.

[0006] Along the same theme but providing some of the advantages of a combi boiler, the combined primary storage unit (CPSU) has combined a central heating boiler and a hot water cylinder in one large housing - which can provide a large amount of hot water when needed. However, a large amount of space is required to accommodate the system.

[0007] All these electric boiler systems use heating elements powered by AC (alternating current power).

[0008] The inventors have realized that a better electric boiler can be produced and have created the claimed solution. Summary of the Invention

[0009] According to a first aspect of the present invention, there is provided a fluid heater as claimed in claim 1.

[0010] Advantageously, there is provided an all-electric or hybrid current fluid heater that can rely solely on a DC power supply (i.e., does not rely on an AC input). This type of heater is environmentally friendly compared to a pure gas (or other combustible fossil fuel combustion) boiler.

[0011] Optional features of the present invention are claimed in the dependent claims - thereby providing various advantages as discussed in the detailed description. These optional features increase the efficiency and intelligence of the heater arrangement of the present invention. As will be understood by those skilled in the art, any one of these optional features can be combined with any other optional feature. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Embodiments will now be described by way of example only with reference to the drawings, in which:

[0013] Figure 1 A schematic view of a boiler according to a first aspect of the present invention is shown;

[0014] Figure 2 A schematic view of a boiler according to another aspect of the present invention is shown;

[0015] Figure 3 A schematic view of a boiler according to yet another aspect of the present invention is shown; and

[0016] Figures 4a to 4d A rear view, a side view, a cross-sectional view (taken along D-D shown in the side view), and a perspective cross-sectional view of a furnace according to yet another aspect of the present invention are shown, respectively. DETAILED DESCRIPTION

[0017] The exemplary embodiments described in the detailed description and the claims are not meant to be limiting. Other embodiments may be used and other changes may be made without departing from the scope of the present invention. Various embodiments are described. Specific embodiments are not intended as an exhaustive description or as a limitation on the broader aspects discussed and claimed. Features described in connection with a particular embodiment are not necessarily limited to that embodiment and may be incorporated into any other embodiment. The protection provided by any applicable doctrine of equivalents is preserved to the maximum extent.

[0018] Terms such as up, down, top, bottom, left, right, inner, outer, vertical, upright, etc. have been used to describe the present invention simply and clearly. These terms should not be construed in a limiting manner. Those skilled in the art will envision other suitable embodiments within the scope of the present invention.

[0019] Referring to Figure 1, shows a water heater 100 (also referred to herein as a boiler) that is used to heat water for use in a standard fluid circuit, such as a radiator heating water circuit. Various aspects of the boiler and boiler system will be described in detail with reference to non-limiting examples. Other details will be apparent to those skilled in the art. Specifically, those skilled in the art can incorporate aspects of known boiler systems, including aspects not described, into the present invention and use them in conjunction with the present invention.

[0020] Generally, the boiler can be a box boiler (also known as a system boiler), or a combination boiler, or any other known type of boiler, or a furnace heater, such as a furnace air heater. Those skilled in the art will be able to adapt the described embodiments to boiler types other than those described. As is well known, these boiler types can be used to supply heating water (e.g., to a radiator circuit) or potable water (e.g., to a faucet circuit) or both. In other examples, instead of heating radiator water, there can be another type of heating fluid flowing through the heating system, such as another fluid, another gas (e.g., air) or oil or any combination thereof.

[0021] Such fluid circuits are well known in the art. Any or each fluid circuit can be a substantially sealed fluid circuit when in use and can optionally be pressurized. In a potable water circuit, the pressure from the main pipe or gravity water supply drives the water so that when the faucet / tap is opened, water flows out of the faucet during normal use. Generally, the radiator circuit is substantially sealed during normal use. Drain points or pressure relief points can be provided at convenient locations to allow inspection or pressure relief or fluid release for maintenance and repair. It is known to use an expansion tank or expansion vessel, which is a small tank used to protect a closed (not open to atmospheric pressure) fluid heating system and domestic hot water system from overpressure. Generally, the expansion tank is partially filled with air, and its compressibility can buffer the shock caused by water hammer and absorb the excess water pressure caused by thermal expansion. In an air heater, the fluid circuit generally includes at least one vent through which the heated air is discharged into the space to be heated. In such a circuit, the air within the circuit is not isolated from the environment - usually at atmospheric pressure or ambient pressure. In some such systems, air is drawn into the furnace during normal operation, heated, and then blown around the heating network.

[0022] In this example, the water heater 100 is a system boiler and includes a boiler housing 102 to house its components. It is often necessary to install the boilers of the present invention in confined spaces. In many examples, the present invention includes features that make the boiler compact to allow the boiler to be installed within the same housing or space footprint as a typical known boiler, even though the boilers of the present invention include new components (as will be described in more detail below).

[0023] The boiler 100 is arranged to heat water in a first circuit, where the first circuit is a hot water heating circuit. The hot water heating circuit includes a plurality of components, and in addition to the boiler 100, it also includes standard household radiators (not shown). In this example, water is used as the heating fluid within the first circuit; in other examples, other known heating fluids may be used.

[0024] Relatively cold water from the first circuit enters the boiler 100 via the cold water input pipe 104, is heated, and then relatively hot water leaves the boiler 100 via the hot water output pipe 106 and returns to the first circuit.

[0025] The boiler 100 includes an electric boiler vessel 110, which is located within a housing 102 between the input pipe 104 and the output pipe 106. The electric boiler vessel 110 is a hermetically sealed container that contains a first electric heating element 108 arranged to heat the water flowing through the vessel 110.

[0026] According to the present invention, the first electric heating element 108 is powered by a DC power source, and in this example, a DC power source in the form of a battery pack 120 is also located within the housing 102. In this example, the boiler is a fully electric boiler, i.e., the heat source is entirely electric. In other examples, the boiler may be partially electric, for example, partially electric and partially gas, or partially electric and partially other combustible fuels - suitable combustible fuels may be combustible fluids such as natural gas, hydrogen, or propane gas, or methane gas, or ethane gas, or butane gas, or suitable combustible oils or combustible solids or coverings such as wood chips or wood pellets, or any combination thereof. In this way, some heating power is provided by the DC electric components, while some heating power is provided by more traditional combustion fuels. This helps to increase redundancy within the system or can be used to operate efficiently in an environment where one or the other power source is scarce. In the present invention, if necessary, the DC power source is large enough to supply or nearly all of the power output of a typical boiler.

[0027] In this example, the capacity of the DC power source is 1 kWh.

[0028] In another example, for a small gas-electric hybrid boiler system setup, the battery capacity may be approximately 1 kWh - this may be useful in a small residence (such as a small apartment), or in a larger residence, it may be useful for increasing the normal hot water supply.

[0029] In another example, for a larger gas-electric hybrid boiler system setup, the battery capacity may be approximately 3 to 5 kWh - this may be useful in a larger residence.

[0030] In another example, for a fully electric boiler system setup, the battery capacity may be around 5 kWh or more. In most cases, if the capacity is 15 kWh to 20 kWh, the hot water demand can be met almost solely by a boiler using direct current. For example, for a fully electric boiler in a small apartment, the battery capacity may be around 10 kWh, for a medium-sized house it may be around 15 to 20 kWh, and for a large house it may be around 25 to 30 kWh.

[0031] In some examples, the battery capacity may be approximately 90 kWh, such as for supplying heating fluid and heated potable water to a larger building.

[0032] In this example, the peak power output of the DC power supply is between 10 kW and 20 kW in some examples and up to 200 kW in some examples. In a low peak demand circuit, the peak power output may be 1 kW or 2 kW. Appropriate peak power output specifications can be made according to specific circuit requirements and will be obvious to those skilled in the art. For example, in one example scenario, a 90 kWh battery can supply 350 kW of power for 10 minutes.

[0033] In this embodiment, the battery pack 120 includes a battery stack in a compact, ordered battery arrangement.

[0034] In this example, a 1 kWh DC battery pack 120 includes one hundred replaceable or rechargeable cylindrical batteries, such as standard-sized 18650 batteries (18 mm diameter and 65 mm length), each having a capacity of approximately 10 Wh. In this example, for compactness, the rechargeable batteries are arranged in a 10x10 stack, and the entire stack can be removed from the battery pack 120 and recharged from outside the housing 102. In another example, the stack can be a 5x20 stack. Depending on the available space in the battery pack, other suitable stack configurations will be obvious. The battery stack is configured to provide substantially consistent usage over time for each battery within the battery stack in a known manner, such that the battery stack operates effectively as a single battery. In some examples, the DC power supply can also be charged from a renewable heat source, such as solar or wind energy or a heat pump or any other suitable source.

[0035] In other embodiments, the DC battery pack can be charged in place through a charging connection (not shown), i.e., without removing any batteries from the housing 102.

[0036] In this example, charging is performed by a battery charging mechanism, which in this example includes an AC-DC converter, and in the example of in-place charging, the boiler also includes an AC-DC converter located within its housing.

[0037] The typical voltage of a 18650 battery is 3.6V. In this example, the batteries in the battery pack 120 are arranged in series, i.e., the effective voltage is approximately 3600V. The battery pack is well insulated. In other examples, the batteries can be arranged differently, for example, all in series (so that the maximum voltage in any single path is 3.6V) or with parallel paths of several series-connected batteries, such as 10 parallel paths, each with 10 series-connected batteries (36V).

[0038] In some embodiments, the batteries can be arranged to provide a voltage that is substantially the same as the AC input power supply voltage - this makes the combination of AC and DC easier and also makes charging easier. For example, in the UK, a 240V battery pack may be provided. In some examples, a slightly lower DC voltage battery pack can be provided, but still having a value approximately the same as the AC input power supply voltage - those skilled in the art will be able to determine suitable values.

[0039] In some embodiments, multiple battery packs or stacks of batteries within a battery pack are provided instead of a single battery pack.

[0040] The boiler 100 housing also has an AC connection 130 to power small electronic components (which have relatively low power requirements compared to the power needed to heat water during normal boiler operation), such as switch circuits, boiler displays, boiler user interfaces, sensors, Wi-Fi, Bluetooth, communication below 1GHz, etc., LED lighting, and other standard boiler components. Other such components include: an igniter or spark generator; an ignition electrode / ionization electrode; a pressure sensor / transmitter (for water), as well as a water pressure switch, a flow sensor / switch (to ensure correct flow of the gas / air mixture before allowing ignition); a combustion sensor (a thermal switch - sometimes described separately by the manufacturer from the temperature sensor); a thermostat; a thermocouple / PRT; control RGB; a multimedia interface; power electronics for the power pack; pumps for water and gas (simple electric pumps or possibly more complex drive electronics). In some examples, this power can also be provided by a renewable heat source, such as solar energy or wind energy or a heat pump or any other suitable source. In some examples, these small electronic components are directly powered by a DC power supply - the boiler has no AC connection.

[0041] In this example, the boiler 100 also includes an electrical control unit (not shown) that is arranged to control any one or more of the following: heating, battery charging, battery discharging, system requirements, switching of the DC power supply. In some examples, the controller is computer-controlled and is arranged to control the amount of heating supplied to the fluid based on or in response to any one or more control factors, including: the required amount of heating; the fluid input temperature at the input point in one or more fluid circuits; the fluid output temperature at the output point in one or more fluid circuits; the fluid temperature at any predetermined point in one or more fluid circuits; the amount of heating capacity available from the first heating element; the amount of heating capacity available from the combustible fuel burner; the instantaneous demand for heated fluid or potable water; the predicted demand for heated fluid or potable water; and the flow rate of the fluid to be heated.

[0042] In addition, in some examples, the fluid heater includes one or more sensors (not shown) that are arranged to sense information related to any one or more control factors and provide the control factor information to the controller. Some sensors are located inside the boiler housing (e.g., for measuring the water temperature or flow rate inside the boiler). Some sensors are located outside the boiler housing (e.g., for measuring the water temperature or flow rate at a desired location in the first circuit outside the boiler, such as in a room of a building). The controller responds to information from such sensors to direct the fuel burner and the electric heating element to heat the fluid.

[0043] In some examples, the controller may have a memory (not shown) associated with it (either integrally or separately) that is arranged to store information about any one or more aspects of the system, such as historical or sensed information related to any control factor, control factor information, sensed information from any sensor, desired output information (e.g., desired room temperature). The controller is able to access information from the memory in a known manner. The controller and the memory may be implemented in standard computerized networks and systems.

[0044] The relatively large battery of the present invention generates heat. Other electrical components of the boiler also generate heat. The inventors have recognized the need for a compact and efficient non-standard cooling system.

[0045] The boiler 100 of this embodiment further includes a cooling system (not shown). Due to the involvement of large DC battery power, and due to the need for additional switching when intelligently using large-capacity DC batteries, and the desire to intelligently use DC-AC (in some embodiments - see below), the electronic devices may be hotter than ordinary boilers. In some examples, the heater includes a high-power switching module arranged to effectively switch high currents, such that the power can be changed in the same resistive electric heating element and the fluid temperature can be smoothly changed. This is particularly important in the drinking water circuit. This feature allows for pulse width modulation within the control circuit. The high-power switching module can be arranged to switch 30 amp or greater.

[0046] In examples that include a battery charging mechanism, the inventors have further found that heat generation within the battery charging system can be a problem - particularly in an AC-DC converter battery charging system that allows voltage to charge a DC battery pack / battery. This type of battery charging mechanism does not yet exist in any boiler system or boiler housing and generates heat. Thus, another advantage of some examples of the present invention is the use of a cooling system (or provision of another separate cooling system) as a heat sink to cool the battery charging mechanism. The battery charging mechanism cooling system is particularly useful because charging can (and should) occur when the system is not heating the building or providing hot drinking water (e.g., in the middle of the night). The cooling system of the present invention allows the heating system to be operated to filter out heat during charging. Even when heated fluid is not required, the controller can be arranged to cause fluid to flow through the fluid heater system to cool the battery charging mechanism. For example, the controller can respond to a prediction or being notified or sensing that the battery charging system should be cooled (e.g., through feedback from a temperature sensor located near the battery charger or after a minimum period of continuous battery charging threshold). This battery charging mechanism cooling feature can be implemented using any of the described embodiments that include a battery charger to create a new embodiment of the present invention.

[0047] In some examples (e.g., where the flow of heated fluid / drinking water is involved in cooling), when the heating system is operating (e.g., demanding drinking water or heated radiator fluid), cooling occurs through the flow of heated fluid / drinking water past the controller / battery / battery charger. However, when the heating system is not operating, the present invention allows the charger cooling system to operate (either through the flow of heated fluid / drinking water or through its own dedicated coolant within its own dedicated coolant loop), specifically for the purpose of cooling the battery charger.

[0048] In some examples, the cooling system uses some of the water output from the radiator, which reaches the cold input pipe 104 (usually at about 35 - 40 °C) for cooling hotter electronic components (ideally, the intention is to keep the electronic components well below 100 °C). In some examples, the elements of the cooling system include positioning the first loop plumbing from the input 104 within the boiler 100 adjacent to or near the components that need to be cooled.

[0049] The cooling system of this example includes a coolant loop having a closed coolant piping system (not shown), through which the coolant is pumped. The closed coolant piping system is configured to facilitate heat transfer between the coolant and the cold water input of the boiler to transfer heat away, and to facilitate heat transfer between the coolant and the battery cells or other components to transfer heat away. This is achieved by routing the piping system to appropriate locations close to any one or more of the boiler components, battery cells, and cold water input.

[0050] In Figure 1 the example, the boiler is configured to be pocket-sized. The housing has dimensions of 400 cm wide x 300 cm deep x 700 cm high and houses a first heater vessel 110 containing a first heating element 108, a DC power supply 102, and a cooling system (in this example). In other embodiments, the housing may have the following dimensions: 390 mm wide, 270 mm deep, 600 mm high; or 400 mm wide, 300 mm deep, 724 mm high; or 400 mm wide, 310 mm deep, 724 mm high; or 440 mm wide, 365 mm deep, 780 mm high; or 440 mm wide, 364 mm deep, 825 mm high; or 440 mm wide, 365 mm deep, 780 mm high; or any other suitable dimensions that would be obvious to a person skilled in the art.

[0051] To provide further compactness, the DC power supply is located at the front of the housing when in use, substantially filling the space between the front and back ends of the housing, and also substantially filling the space between the left and right sides of the housing. The left and right sides of the boiler both have walls that are relatively difficult to access when in use. The front is relatively easy to access and is typically used to access the internal components during maintenance.

[0052] In some examples, the housing 100 includes an access door arranged to allow access to the internal components of the heater (e.g., for maintenance or repair), and the DC power supply is arranged within or integrally with the access door. This also increases the overall compactness and ensures that no further removal or manipulation of the DC battery is required to access the internal boiler components (e.g., for repair / maintenance).

[0053] In this example, the boiler 100 further includes a thermal break or thermal shield (not shown) located between the DC power supply and the first heater vessel. The thermal break or thermal shield can include any one or any combination of the following: an air gap; a gap (partially or completely) filled with a thermal insulation material; a gap (partially or completely) filled with an infrared reflective material; a gap (partially or completely) filled with an insulator or a low thermal conductivity material.

[0054] In some examples, the thermal shield can include an associated thermal shield cooling mechanism that is arranged to transfer heat from the thermal shield area to another area that is safer for dissipating heat, and includes any one or more of the following:

[0055] · A fluid material that takes heat away from the area (e.g., from the thermal shield area to a dissipation area (i.e., another area that is safer for dissipating heat than the thermal shield area));

[0056] · An active cooling mechanism, such as a Peltier device (actively transfers heat from one side to the other, e.g., to another area that is safer for dissipating heat than the thermal shield area);

[0057] · A freezer cabinet (similar to a typical refrigerator) located within the boiler housing and arranged to substantially enclose the DC power supply; and

[0058] · An air flow mechanism, such as a blower, arranged to draw air from outside the housing or from inside the housing to provide the desired cooling effect.

[0059] The electric heating element can be wound around the tubes or components of the first circuit - benefits include easy manufacturing, easy reconfiguration, replacement / upgrade / repair (if needed) (since the heating element is located outside the tube / component (and the wet surface does not need to be contacted). The heating element is easily visible and thus easily inspected (e.g., during regular maintenance) for degradation. Such heating elements are also easier to clean. Such heating elements are not affected by sludge in the water circuit (this problem is common in radiator water circuits).

[0060] In other embodiments, the electric heating element can be placed inside the first circuit conduit / tube - benefits include compactness and less heat loss to the environment (during normal heating operation, heat is almost completely retained in the desired water circuit).

[0061] In other embodiments, the electric heating element can be built into the wall of the water circuit conduit of the first circuit - the benefit is that these elements are robust, not easily damaged by dirty water, and experience less heat loss (compared to equivalent wrapped heating elements).

[0062] In other embodiments, heating can occur in the chamber (instead of in the tube). In such embodiments, the tube of the first circuit can lead to and out of the chamber, and one or more electrical heating elements can be disposed anywhere within the chamber or embedded in the wall of the chamber or wound around the chamber wall or any combination thereof. The advantage of using such a chamber rather than just heating the water / heated fluid as it passes through the fluid tube of the circuit is that a longer or more circuitous path can be provided and the heated fluid can be allowed to remain near the heating element for a longer time during which more heat can be transferred (relative to the direct path through the straight tube section).

[0063] In still other examples, depending on the particular application, there can be a combination of the type and arrangement of the electrical heating elements used.

[0064] In another embodiment (not shown), the boiler includes a hybrid electric-gas boiler vessel rather than a vessel having only electrical heating elements. In such an embodiment, multiple heating mechanisms are provided within the same sealed boiler vessel chamber. One is an electrical heating mechanism; the other is a gas burner mechanism. The gas burner mechanism is of a known type. In addition to natural gas, another mechanism could be a different fuel burner (e.g., hydrogen, propane gas, oil). The electrical heating mechanism can be in any suitable form. In this example, it is in the form of electrical heating elements. In such examples, the DC power supply will still be large enough to supply the electrical power to the electrical heating elements sufficient to provide all or most of the required heating of the fluid / water. In one example, the boiler can be arranged to heat the water in the first circuit (e.g., for heating water to supply to a radiator circuit). The electrical heating element or elements can be located anywhere within or around the burner vessel such that the water can be heated by either or both of the gas and electrical heating mechanisms. The heating element can be a wire which can be heated by passing an electric current through it and is suitably arranged to transfer heat where needed (e.g., wound around a water pipe or a baffle (or any other component within the burner vessel)).

[0065] There may be a heat exchanger within the gas burner vessel. The heat exchanger is arranged to concentrate the heat from the combustion gas, the heated electrical element or both onto the water pipe or each water pipe. The heat exchanger can be metal or ceramic. In one example, the heat exchanger can be in the form of one or more plates (e.g., metal plates) partially or completely surrounding the water pipe. The electrical heating elements can be arranged between the plates. In another example, there can be a large piece of suitable material (e.g., a large piece of ceramic) arranged around the water pipe.

[0066] Refer to Figure 2, in another example, the water heater 200 includes a combi-boiler that is arranged to heat water in a second circuit (for heating and supplying potable water) and a first circuit (for heating and supplying heating fluid to a radiator network). The second circuit has a different duct arrangement, i.e., different plumbing from the first circuit, such that the fluids in the two circuits do not meet (such that the potable water is not contaminated by the radiator water).

[0067] Some components of boiler 200 are similar to those of boiler 100 and have similar reference numerals in the format 2xx instead of 1xx.

[0068] Boiler 200 includes a housing 202 that contains a first heater vessel 210, which contains a first heating element 208, a DC power supply 202, and a cooling system (not shown).

[0069] Relatively cold water from the first radiator circuit enters boiler 200 via the cold radiator fluid input pipe 204, is heated, and then relatively hot water leaves boiler 200 via the hot water output pipe 206 to the first radiator network circuit.

[0070] Boiler 200 includes an electric boiler vessel 210 that is located within housing 202 between the input 204 pipe and the output 206 pipe. The electric boiler vessel 210 is a hermetically sealed container that contains a first electric heating element 208 arranged to heat the water flowing through the vessel 210.

[0071] According to the present invention, the first electric heating element 208 is powered by a DC power supply, which in this example is in the form of a battery pack 220 that is also located within housing 202. In this example, the boiler is an all-electric boiler, i.e., the heat source is entirely electric. In other examples, the boiler can be partially electric, e.g., partially electric and partially gas, or partially electric and partially other combustible fuels - suitable combustible fuels can be hydrogen or propane gas or suitable combustible oils or wood chips or wood pellets or any combination thereof. Thus, part of the heating power is provided by the DC components, while part of the heating power is provided by more traditional combustion fuels. This helps to increase redundancy within the system or can be used to operate efficiently in an environment where one or the other power source is scarce. In the present invention, the DC power supply is large enough, if needed, to supply or nearly all of the power output of a typical boiler.

[0072] In some such examples, e.g., in examples where the intake is used to assist the combustion process (e.g., when burning a gas or combustible fuel), the cooling system can include using the intake to cool the battery pack and / or electronic components since the inhaled air is relatively cold; at the same time, the air will be heated and make the combustion process more efficient. This can be achieved by routing the intake path near the battery pack or the components that need to be cooled.

[0073] In this example, the capacity of the DC power supply is 5 kWh.

[0074] Other modification examples (such as hybrid electric-gas power, AC-DC control, cooling configuration, etc.) are similar to those described with reference to the previously described embodiments (such as reference Figure 1 ).

[0075] In Figure 2 's example, the hot water in the first boiler vessel 210 is also arranged to heat the water in the second circuit (without directly heating the water in the second circuit). The second circuit includes a drinking water circuit (such as supplying tap water for washing, bathing, drinking, etc.). The relatively cold water from the second circuit enters the boiler 200 via the main pipe cold water input pipe 205 (which is supplied via the main pipe water pipe), is heated, and then the relatively hot drinking water leaves the boiler 200 via the hot water output pipe 207 and reaches the second faucet circuit.

[0076] Between its input 205 and output 207, the second circuit includes a pipe section configured to transfer heat from the first container 210 thereto. In this described example, this is achieved by positioning the pipe section adjacent to the container 210 such that heat can be effectively transferred to the pipe section during use. The pipe section includes a spiral pipe wound around the container 210 to further assist in heat transfer therebetween. In another example, instead of or in addition to the spiral pipe wound around the container, the water is heated by a wet heat transfer box. This avoids the need to heat the radiator water every time the drinking water is heated. In such an example, the water in either circuit can be heated independently - the pipes from both circuits enter a heat exchange container where heating can occur for either one or both circuits.

[0077] The battery pack 220 is located on top of the housing 202, away from the heating container 210, and is isolated from the heating container 210 by a thermal shield (not shown), as described for other examples.

[0078] Referring to Figure 3 , in another example, the water heater 300 includes a combined boiler arranged to heat the water in a second circuit (for heating and supplying drinking water) and a first circuit (for heating and supplying heated fluid to a radiator network). Figure 3 's system is the same as Figure 2The system is similar (with similar reference numerals having a format of 3xx instead of 2xx), except that the potable water in the second circuit is mainly heated by different means. The combined boiler 300 includes an electric boiler vessel 310, which is located within a housing 302 between an input 304 pipe and an output 306 pipe. The electric boiler vessel 310 is a hermetically sealed container that contains a first electric heating element 308 arranged to heat the water flowing through the vessel 310.

[0079] According to the present invention, the first electric heating element 308 is powered by a DC power source, which in this example is in the form of a battery pack 320 that is also located within the housing 302. In this example, the boiler is a fully electric boiler, i.e., the heat source is entirely electric. In other examples, the boiler can be partially electric, for example, partially electric and partially gas, or partially electric and partially other combustible fuels - suitable combustible fuels can be hydrogen or propane gas or suitable combustible oils or combustible solids or coverings or any combination thereof. Thus, part of the heating power is provided by the DC power components, while part of the heating power is provided by more traditional combustion fuels. This helps to increase the redundancy within the system or can be used to operate efficiently in an environment where one or the other power source is scarce. In the present invention, if needed, the DC power source is large enough to supply or nearly all of the power output of a typical boiler.

[0080] In this example, the capacity of the DC power source is 20 kWh.

[0081] Contrary to Figure 2 the example of Figure 3 the example of the electric heating mechanism includes a second electric heating element arranged to effectively transfer heat to the water in the second circuit. In this example, the boiler 300 includes a second electric boiler vessel 311 that contains a second electric heating element 309 within the path of the second circuit between an input pipe 305 and an output pipe 307. In this example, the DC battery pack also powers the second electric heating element 309.

[0082] Various modifications can be made to the present invention without departing from its scope.

[0083] For example, although the examples of the present invention have been described with respect to water boilers, the same inventive concept can be applied to other (partially or fully) electric fluid heaters, for example, air heaters (also known as furnaces) that are common in North America. Such systems typically include a fan for blowing the heated air - this is not shown in any of the drawings for clarity. Systems for heating other fluids will be apparent to those skilled in the art.

[0084] Figures 4a to 4dAn example is shown - according to this embodiment, the furnace heater 400 is arranged to provide heated (or cooled) air. The furnace 400 includes a housing 402, an air inlet 404, and a fan 406 located near the air inlet to draw air from the environment into the furnace housing 402. The housing also has an air outlet 408 through which the heated air leaves the furnace housing. Between the inlet 404 and the outlet 408 is an air duct 410. Those skilled in the art will recognize variations of such furnace air heaters.

[0085] The furnace includes a heat exchanger 412 which is arranged to provide heat to the air passing through the duct 410. In this example, the heat exchanger is located within the duct (but in other examples it can be located outside the duct). In this example, a plurality of electric heating elements 414 are located inside the body of the heat exchanger 412. The electric heating elements 414 are arranged to supply heat when powered by an electric current. The furnace includes a large DC power source, in this example in the form of six DC battery packs (other configurations will be apparent). The DC power source in this example includes a power source of the type previously described with respect to the boiler and is the only power source (i.e., no AC power source powers the heating elements). In other examples, the heating elements can also be powered by an AC power source. In this example, the battery capacity is approximately 5 kWh - this value may be relevant in other examples discussed in relation to the previous examples.

[0086] In this example, the power pack provides surge and steady-state power to the heating elements within the hot air delivery system. In some examples, a second fluid circuit for hot water is also provided - in such examples, on-demand hot water can be managed within the furnace through power electronics (for powering the electronic components of the furnace). The number / power of the DC power packs can be adjusted to meet specific installation requirements. In some examples, the power electronics are cooled by circulating air or other fluids and can be used to preheat the air flow through the ducts. The modular DC power packs are designed to be easily replaceable and are located on a side of the housing that is easily accessible.

[0087] In some such embodiments of the present invention, the battery pack can include a plurality of modular battery sub-groups that are stacked together (or separated in different parts or in whole by boiler components) to form the battery pack. These sub-groups are configured to be manually handled; that is, they have a suitable weight for handling. They can also have a suitable shape for easy handling. The battery pack as a whole can be thermally managed or thermally shielded (i.e., allowing the heat of the battery pack cells to dissipate to a suitable location in the environment, but also not receiving unwanted heat from other boiler components such as the heat exchanger). The sub-groups can be thermally managed or thermally shielded individually (i.e., allowing the heat of the battery pack cells to dissipate to a suitable location in the environment, but also not receiving unwanted heat from other boiler components such as the heat exchanger).

[0088] The size of the subgroups can be designed to fit within the boiler housing, i.e., their width is approximately the same as, only less than, or significantly less than the width of the boiler housing. When stacked, the height of the subgroups can be such that the combined height of the required number of subgroups is approximately the same as, only less than, or significantly less than the height of the boiler housing.

[0089] In some examples, the subgroup (or stack or other arrangement of subgroups) is no larger than the boiler housing, e.g., width 390 or 440 cm; depth no greater than 270 or 365 cm, and height no greater than 600 or 825 cm.

[0090] There is little wasted space within the boiler housing 402. The large, powerful battery pack is both useful and fills the space that would otherwise be empty.

[0091] In some embodiments, the heating element or the heating elements can be powered by both a DC power source and an AC power source. In such embodiments, the DC power source is arranged to at least partially power the heating element. In some such embodiments, the DC power source can fully power the heating element at some times and partially power it at other times (depending on factors such as the time of day or the availability of power from renewable energy sources).

[0092] In an example with multiple fluid circuits, such as in a combi-boiler example, in addition to a large DC power source there are other power sources, a first heating element can be arranged to heat the fluid in one of the first and second circuits, and a combustion heater can be arranged to heat the fluid in the other of the first and second circuits, e.g., tap water is heated only by the power source, and hot water is heated by a combustible fuel source.

[0093] Each heater vessel can be provided with more than one heating element.

[0094] For any embodiment described as being purely electric, one skilled in the art will understand that it can be provided in a partially electric and partially combustible fuel form.

[0095] Any example can include a DC power interface arranged to receive a DC power source, where the DC power interface is configured to receive more than one type of DC power source, such as a nickel-metal hydride battery pack, a nickel-cadmium battery pack, and a lithium battery pack or any hybrid pack containing a mixture of any of these cell types.

[0096] Any example including a DC power unit can include a safety cut-off mechanism arranged to disconnect the unit from powering the electric heating element. The safety cut-off mechanism can include a main switch or an automatic main switch; in some examples, the safety cut-off mechanism includes a contactor. Advantageously, a safe and simple DC switching mechanism is thereby provided.

[0097] An electric heating element or battery or both of the foregoing type can be retrofitted to an existing electric, gas (or other combustible fuel), or gas - electric hybrid (unknown, but described in the applicant's co - patent application) fluid heater to provide a fluid heater within the scope of the present invention. Compared with the original fluid heater, the fluid heater of the present invention can be more powerful, more efficient and less dependent on burning combustible fuels. Such examples may be particularly suitable for retrofitting existing gas boilers with electric heating capabilities. For example, the electric heating element can be coated on the conduit part or the pipe part near it, coated in it, sprayed, contained in it, wrapped around it, partially or completely embedded in it, or otherwise associated with: the outlet of its gas burner container; its inlet to the burner container; or both. The heating element can be powered by direct current, alternating current, or a combination thereof. In some examples, a battery, such as a large - sized battery of the foregoing type, can be attached to the burner container together with a control mechanism (such as control electronics and / or software) to control the amount of heating provided by the electric heating element compared to the combustible fuel source. The control mechanism can also control the amount of heating provided by direct current, alternating current, or a combination thereof.

[0098] In examples where the circuit includes a heated water circuit such as a radiator circuit, the boiler / heater also includes a pump as known in the art, such as a water pump (not shown in any of the figures for clarity).

[0099] In examples where the circuit includes a drinking water circuit, the input typically comes from the main pipeline tap water input, which is pressurized and thus does not require a pump. In some examples, when the input is from an unpressurized clean water source, a pump can be provided.

[0100] In some examples, the DC power supply is located at the top inside the housing. In such examples, the wet components (such as tubes or chambers containing fluid) are only located below the DC power supply. In some examples, the DC power supply can occupy approximately 80% of the space at the top inside the housing.

[0101] In some embodiments, the first heating element is arranged to provide heating specifically in the first fluid circuit, and the second heating element is arranged to provide heating specifically in the second fluid circuit, or vice versa. For example, one heating element can be dedicated to providing heating for the radiator circuit, while the other heating element can be dedicated to providing heating for the drinking water circuit. Thus, suitable customized dedicated elements can be used for different circuits with different requirements.

[0102] In any of the examples described, the said, any, or each heating element can be any element that emits heat when current passes through it, such as any arrangement of resistance wires or wires that emit heat when current passes through them, such as (but not limited to):

[0103] A thin film (polyimide on a conductive metal);

[0104] Ceramic (with nickel-chromium-aluminum, etc. embedded in the ceramic sheath) wire;

[0105] Bare wire (tungsten such as nickel, nickel-chromium alloy, Kanthal, Stellite, etc.);

[0106] Encapsulated wire - such as nickel-chromium alloy with a silicone sheath;

[0107] Mineral insulated electric wire - copper sheath / nickel-chromium alloy, cupronickel / chromium-nickel-iron alloy, steel sheath / nickel, chromium-nickel-iron alloy sheath / nickel alloy wire, and various mixtures thereof. Components can be drawn to scale or manufactured to the final size, etc. The insulating material is usually Al2O3 or MgO;

[0108] Ordinary wire, helical wire, bus bar with a winding element in the middle.

[0109] In any example describing a single heating element, it can be replaced by one or more different heating elements, which will be obvious to those skilled in the art.

[0110] For example, one or more electric heating elements can include a conductive heating element coating on any one or more of the following: the inner surface of at least one pipe wall; and the outer surface of at least one pipe wall; and the surface of a combustion fuel heat exchanger, baffle, or any other component. One or more of the electric heating elements can include induction heating elements, for example, so that it / they can be powered by induction (without direct contact).

[0111] In some cases, multiple different electric heating elements are arranged to heat fluids in different parts of a pipe. In some examples, multiple different parts of the heating element are disposed within the fluid pipe, and each part can be controlled together or separately, for example, providing different degrees of heating at different part locations. This is effective in cases where the combustion heating degree is different at different locations of a burner vessel - the electric heating element can provide less heating in the part where the burner can provide more heating, and the electric heating element can provide more heating in the part where the burner can provide less heating. In another use case, it may be necessary to provide different degrees of heating in different parts of a fluid path, for example, at the initial heating start-up, when the fluid is first heated from cold, such as when first turning on a faucet, stronger heating may be provided at the start of the fluid path than at the end because the initially input fluid is particularly cold.

[0112] In some of these examples, the elements can be fully embedded in the fluid pipe so that no part of them protrudes or projects from the pipe (e.g., no external electrical connection points).

[0113] In some examples where the heating elements are disposed in different regions (not continuously along the entire length of the pipe), the gaps between the different regions can be formed by masking the gap portions of the pipe during the coating / spraying process (e.g., using a spray mask).

[0114] In some examples, the present invention provides a single-shell fluid heater having an electric heating element arranged to be powered by both a large DC power supply and an AC power supply, and having an on-board controller and a controller cooling system. The inventors recognized that the components of this type of system have significantly different cooling requirements.

[0115] In some examples (where the heating element can also be powered by an AC power supply), the controller can be arranged to provide a shower saver algorithm as follows: if the DC power supply is not available (e.g., if the battery charge is low or zero), then switch to powering the electric heating element only by the AC power supply. Instant (i.e., on-demand when the faucet is opened) hot water is provided only by the AC power supply; the power provided is then less than the power that the large DC power supply can provide. Thus, the controller is programmed to ensure that there is always some minimum threshold of remaining DC capacity, e.g., to allow for high-power showers, etc. The user can selectively activate or deactivate this function via a user interface that sends commands to the controller. In some examples, the minimum threshold of DC capacity can be 5% of the total battery capacity to be retained.

[0116] In some examples, the present invention provides a fluid heater that enables the safe provision of a large modular power pack that can be easily replaced within the confines of the heater housing. The large power pack (which can consist of multiple subgroups) has sufficient capacity such that the entire heating load of a typical domestic residence can be provided by the power supply. As previously mentioned, a heat shield is used to safely place a power pack of this size within the housing. Since the battery charger cooling mechanism can typically operate at different times from the controller and battery cooling mechanisms, it can incorporate or include a cooling mechanism separate from or different from the controller and battery cooling mechanisms.

[0117] In some cases, there may be multiple cooling mechanisms, such as at least one cooling mechanism associated with the controller, at least one cooling mechanism associated with the battery, and at least one cooling mechanism associated with the battery charger.

[0118] In some examples, the cooling system can be a passive cooling system (instead of or in addition to the aforementioned cooling system), arranged to transfer heat from components to be cooled (such as boiler electronics or a DC power supply or a battery charger or any combination thereof). The passive cooling system may not include a flowing fluid. The passive cooling system can include a heat sink (such as an aluminum block, for example, an aluminum block of 20mm x 40mm x 80mm, which has natural convection fins for dissipating heat to the environment). The passive cooling system can include a large thermal mass, such as a heater housing.

Claims

1. A partial or complete electrohydrodynamic heater, the heater being arranged to heat a fluid in a first circuit, Among them, the heater comprising a heater housing arranged to accommodate: a first electrical heating element contained in a first heater vessel, the first electrical heating element being arranged to heat the fluid in the first circuit; and a DC power supply arranged to at least partially power the first electrical heating element, the DC power supply having a capacity of at least 1 kWh, the heater further comprising a thermal shield located between the DC power supply and the first heater vessel.

2. The heater according to claim 1 is further arranged to heat a fluid in a second circuit, wherein, The fluid in the first circuit comprises a heating fluid and the fluid in the second circuit comprises tap water, or vice versa; and wherein the first electrical heating element is arranged to heat the fluid in the first circuit, or both the first and second circuits.

3. The heater according to claim 2, comprising an electrical control unit arranged to control any one or more of: heating, DC power supply charging, DC power supply discharging, system requirements, switching of the DC power supply.

4. The heater according to claim 3, comprising a cooling system arranged to provide cooling to the electrical control unit, the DC power supply, or both.

5. The heater according to claim 4, wherein, The cooling system comprises a coolant circuit having a coolant input pipe arranged to carry an input coolant to the DC power supply or the electrical control unit or both, a coolant output pipe arranged to carry an output coolant away from the DC power supply or the electrical control unit or both, and a coolant radiator arranged to receive the coolant output pipe and dissipate heat from the coolant output pipe before the coolant is recirculated to the coolant input pipe, wherein the coolant output pipe, the radiator, or both are configured to transfer heat to any one or more of: the fluid in the first circuit; the fluid in the second circuit; the heater cold water input pipe; the heater cold fluid inlet; and the heater heated fluid return pipe.

6. The heater according to any one of the preceding claims, wherein, The DC power supply comprises a battery pack.

7. The heater according to any one of the preceding claims, wherein, The heater housing has dimensions of 390 to 440 cm wide, 270 to 365 cm deep, and 600 to 825 cm high.

8. The heater according to claim 4 or 5 above, wherein, The heater housing is arranged to accommodate the cooling system.

9. The heater according to claim 7 or claim 8, wherein, The DC power supply is located at the front of the housing in use or at the top of the housing in use.

10. The heater according to any one of claims 7 to 9, wherein, The DC power supply: substantially fills the space between the front and rear ends of the housing; and substantially fills the space between the left and right sides of the housing.

11. The heater according to any one of claims 7 to 10, wherein, The housing includes an access door arranged to allow access to the internal components of the heater, and the DC power supply is arranged within the access door or integrally with the access door.

12. The heater according to claim 2 or claim 5, further comprising a combustion heater including a gas or oil burner, the combustion heater being arranged to heat the fluid in the first circuit, the second circuit, or both.

13. The heater according to claim 12, wherein, The first electric heating element is arranged to heat the fluid in the first circuit, and the combustion heater is arranged to heat the fluid in the second circuit.

14. The heater according to claim 2, 5, 12 or 13, further comprising a second electric heating element arranged to heat the fluid in the first circuit, the second circuit or both.

15. The heater according to claim 14 further includes an alternating current power supply arranged to at least partially power the second electrical heating element, and wherein, The first electric heating element is arranged to be powered only by the DC power supply and the second electric heating element is arranged to be powered only by the AC power supply.

16. The heater according to claim 15, wherein, The first heater container contains the second electric heating element.

17. The heater according to claim 15, wherein, The housing is arranged to accommodate a second heater container which is arranged to contain the second electric heating element.

18. The heater according to any one of the preceding claims, further comprising a controller arranged to control power distribution, taking into account one or more of the following: The capacity of each electric heating element; and / or The capacity of each power supply.

19. The heater according to any one of the preceding claims, comprising a DC power supply interface arranged to receive the DC power supply, and wherein, The DC power supply interface is configured to receive more than one type of DC power supply, including any combination of nickel-metal hydride unit battery packs, nickel-cadmium unit battery packs, lithium unit battery packs or hybrid unit type battery packs.

20. The heater according to any one of the preceding claims, comprising an AC-DC converter charger arranged to charge the DC power supply and located within the housing.

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