electric space heater

Abstract

An electric space heater (1) is disclosed that includes a first electric heating device (8) configured to be powered by both an AC power source (22) and a DC power source (20), and a controller (24) configured to control the distribution of power from the DC power source and the AC power source to the first heating device.

Description

[Technical Field]

[0001] ELECTRIC SPACE HEATER FIELD OF THE INVENTION The present invention relates to electric space heaters, particularly but not exclusively to freestanding electric space heaters for heating spaces on demand. [Background technology]

[0002] A space heater is a freestanding heating device designed to heat a small area, or "space," rather than an entire building or large room. Space heaters can be used to supplement central heating or to provide heat to small areas where heat is needed.

[0003] Space heaters that use electricity as a fuel source are known and can be powered by plugging them into an outlet to access a mains AC power supply. Some space heaters have a built-in thermostat that allows the user to set the desired temperature, and they may also have safety features such as automatic shut-off and tip-over protection.

[0004] Space heaters are often used in small rooms or spaces that are difficult or expensive to heat with a central heating system or where additional heat is needed temporarily. While space heaters can be an energy-efficient and cost-effective way to heat small areas, they should be used with care to avoid the risk of fire or other hazards. Electric space heaters work by using electricity (e.g., mains AC power) to power a heating element, such as a coil or metal block. When energized, the heating element heats up and begins to transfer heat to the surrounding air or fluid (e.g., oil), or other objects.

[0005] There are many types of electric heaters, including: (1) Convection heaters: These heaters work by using electricity to power a heating element, such as a coil or metal block, which energizes the heating element, heats up, and begins transferring heat to the surrounding air or fluid (e.g., oil) or other object, creating a current of warm air that circulates throughout the room. Heat is generated by the heating element's resistance to the electrical current. As power passes through the element, it encounters resistance, causing the element to heat up. In convection heaters, the heating element is typically placed within a housing or enclosure designed to allow air to circulate around it. As the air is heated by the element, it rises and displaces cooler air coming from the room, creating a current of warm air that circulates throughout the space. This process helps distribute heat evenly and increase the overall temperature of the room. (2) Radiant Heater: Radiant heaters operate by using electricity to power a heating element, such as a coil or metal block. When energized, the heating element heats up and begins to transfer heat to surrounding objects and surfaces by emitting infrared radiation. Infrared radiation is a type of electromagnetic radiation with a wavelength longer than visible light and invisible to the human eye. Infrared radiation can pass through air and is absorbed by objects and surfaces it comes into contact with, raising their temperature. Heat is generated by the heating element's resistance to electrical current. When electricity passes through the element, it encounters resistance, causing the element to heat up. In a radiant heater, the heating element is typically placed in a housing or enclosure designed to emit infrared radiation into the surrounding space. The radiation is absorbed by objects and surfaces within the room, helping to raise the overall temperature of the space. (3) Fan Heater: A fan heater works by using electricity to power a heating element, such as a coil or metal block and a fan. When the heating element is energized, it heats up and begins to transfer heat to the surrounding air or objects. At the same time, a fan is used to blow the heated air into the room, creating a current of warm air that helps raise the temperature of the space. Heat is generated by the heating element's resistance to the electric current. When electricity passes through the heating element, it encounters resistance, causing the heating element to heat up. Generally, fan heaters are very efficient and can be used to heat a small area or an entire room. (4) Baseboard heaters: These heaters are installed along the baseboard of the wall and use a heating element to warm air that is drawn through the heater by natural convection. (5) Oil-filled Radiators: Oil-filled radiators are a type of electric heater that uses oil as a heat transfer fluid. They work by using electricity to heat the oil inside the radiator. Once the oil is heated, it begins to circulate through the radiator, transferring its heat to the radiator's metal fins. These fins then radiate the heat to the outside, warming the surrounding air. The oil inside the radiator never actually boils or evaporates, so it never needs to be replaced. This makes oil-filled radiators very efficient and long-lasting. They are also safe to use, as the oil does not ignite or produce harmful fumes. Oil-filled radiators heat slowly but retain heat for a long time, making them a good option for providing stable, consistent heat in a room. Oil-filled radiators are also relatively quiet and do not produce the dry, hot air that other types of heaters produce. Inside the radiator is a heating element made from conductive materials such as copper or aluminum. When electricity flows through the heating element, it generates heat due to its resistance to the current. This heat is then transferred to the oil in the radiator, raising the oil's temperature. The heating element is typically located near the bottom of the radiator, where the oil is coldest. As the oil heats up, it becomes less dense and begins to rise through the radiator. As it rises, it passes over the radiator's metal fins, which transfer the heat to the surrounding air. The hot oil then flows back to the bottom of the radiator, where it is reheated by the heating element, and the process begins again. The oil temperature and the radiator's heat output can be controlled by a thermostat, which turns the heating element on and off as needed to maintain the desired temperature and / or provides a safety shut-off mechanism.

[0006] Electric heaters are generally efficient and can be used to heat small areas or entire rooms. They are also easy to install and operate and do not produce harmful emissions. Summary of the Invention [Problem to be solved by the invention]

[0007] The inventors realized that a better electric space heater could be made and came up with the solution set forth in the claims. [Means for solving the problem]

[0008] According to a first aspect of the present invention, there is provided a fluid heater as set forth in claim 1.

[0009] Advantageously, an electric space heater is provided that can use a combination of DC and AC power (i.e., does not need to rely on AC input). This type of heater allows for intelligent use of available power options, thereby operating more efficiently while providing high performance and in an environmentally friendly manner. Intelligent mixing of AC and DC power reduces the risk of overwhelming a home or local grid (e.g., during peak demand periods when many devices (not just heating devices) may be plugged into the AC mains). Furthermore, fluid heaters may be provided that typically have higher peak power; for example, if a space needs to be initially heated from a cold state, the heater of the present invention may operate at significantly higher peak power than if only the AC mains were used. Furthermore, intelligent use of DC power is useful in AC mains cut scenarios. The ability to control and balance the use of DC-supplied electricity to power an electric heating device in conjunction with normal AC power also solves responsiveness issues. That is, a combination of AC and DC can be used to heat more quickly compared to AC mains alone. This means that a space can be heated more quickly from the moment a demand for heating is made (e.g., via a direct request from a user, or via an indirect or automated device that predicts the user's anticipated needs). In some aspects, the space can begin to heat before a person arrives in the space. This is more efficient and better from a user experience perspective.

[0010] The heater of the present invention can help avoid circuit overloads, for example, by avoiding reaching main AC power limits. For example, running several spot heaters can overwhelm a local grid, such as a typical home's mains circuit; assuming 3 kW space heaters, only eight can be run in a home (before the mains power is overloaded at 100 A). Typically, a home or office AC circuit has other loads to consider (especially during busy, high-demand times of day). The power limits available from domestic power sockets vary depending on the country and type of outlet used. For example, in the United States, a standard 120-volt outlet can provide a maximum current of 15 amps for a maximum power draw of 1,800 watts. However, some outlets in the United States are rated at 20 amps and can supply up to 2,400 watts. These are maximum ratings, and continuous operation of devices at or near these limits is not recommended, as they may be dangerous and could damage the electrical system. In the UK, standard domestic power outlets are rated at 230 volts and 13 amps, for a maximum power consumption of 2,990 watts. However, as in the US, these are maximum ratings and it is not recommended to operate devices continuously at or near these limits, as the outlet rating also depends on the building's overall electrical system and the wiring within the walls.

[0011] By using the DC power supply of the present invention instead of or in addition to the main AC power supply, power demand loads in domestic circuits can be managed by smoothing or reducing peaks in power demand loads (e.g., throughout the home). Thus, for example, the DC power supply can be recharged during low demand times in the home (e.g., at night when people are sleeping, or when people leave the room and the heater is switched off when the room is no longer occupied). During high demand times in the home, such as the morning rush (when many different devices are connected and using grid AC), the DC can be configured to support or boost the AC, for example, depending on the particular needs.

[0012] In some embodiments of the present invention, a DC power supply can be used to provide extra power and heating in short bursts when it is needed most, for example, when initially heating a space from a cold state.

[0013] In some embodiments, the maximum power from heating from a combination of AC and DC power sources is greater than the maximum power achievable using AC power alone. Typically, in some embodiments, at least a 25% heating boost (in kW heating power supplied) can be provided when needed. This allows for a short period of progressive heating when needed, which can then be gradually phased out / abruptly removed once the thermal conditions in the space reach a measured threshold or when the user directly indicates that progressive heating is no longer needed. In this case, the electric heating element can operate solely on AC power.

[0014] During times of potentially high AC grid load, it may be desirable to reduce the amount of mains AC used to power an electric heating device (e.g., while maintaining the same heat output (although not necessarily, which may result in a slight decrease or even an increase in heat output)). In such cases, the controller of a heater of the present invention may be configured to switch between using AC and DC power sources to power the device to reduce the load on the grid. In some cases, switching between AC and DC may occur at approximately 50 Hz to reduce the average power drawn from the AC mains. If the AC mains operates at 50 Hz and the DC power output matches the RMS average output of the mains, the DC power source can meet approximately half of the heating demand while maintaining the same heating output as using AC alone in a conventional electric space heater. The space heater of the present invention, in that scenario, reduces the load on the AC grid by approximately half without reducing the amount of heat delivered. Other AC+DC balanced configurations will be apparent to those skilled in the art, depending on the detailed requirements or desires of a particular system.

[0015] In some or all embodiments, the AC power source may be configured to heat the space (continuously) for a relatively long duration, and the DC power source may be configured to: By supplementing AC power, it heats a space more intensely for a relatively short period of time, or Reduce the strain on AC grid circuits, or Amplify the heating capacity of your space heater beyond the capacity of AC alone, or Run in a lower power mode than the AC mains to reduce the overall AC energy used, or Run in low power mode to reduce overall costs compared to using AC mains, or This allows you to safely leave the unit unplugged (i.e., you want to use AC) for short periods of time, or for long periods of time at very low output.

[0016] Optional features of the present invention are as set forth in the dependent claims, which provide various advantages as described in the detailed description. These optional features add efficiency and intelligence to the heater setup of the present invention. As will be appreciated by those skilled in the art, any of these optional features can be combined with any other optional functionality.

[0017] Embodiments will now be described, by way of example only, with reference to the accompanying drawings, in which: [Brief explanation of the drawings]

[0018] [Figure 1] 1 shows a schematic diagram of an electric space heater according to a first embodiment of the present invention; [Figure 2] 1 shows a schematic diagram of an electric space heater according to a second embodiment of the present invention. [Figure 3] FIG. 1 shows a schematic diagram of an electric space heater according to a third embodiment of the present invention. [Figure 4] Figure 4a shows a different angle view of a fan blower space heater according to another embodiment of the present invention, Figure 4b shows a different angle view of a fan blower space heater according to another embodiment of the present invention, Figure 4c shows a different angle view of a fan blower space heater according to another embodiment of the present invention, and Figure 4d shows a cross-sectional view of a fan blower space heater according to another embodiment of the present invention. [Figure 5] Figure 5a shows a different angle view of a fan blower space heater according to another embodiment of the present invention, Figure 5b shows a different angle view of a fan blower space heater according to another embodiment of the present invention, Figure 5c shows a different angle view of a fan blower space heater according to another embodiment of the present invention, Figure 5d shows a different angle cross-sectional view of a fan blower space heater according to another embodiment of the present invention, and Figure 5e shows a different angle cross-sectional view of a fan blower space heater according to another embodiment of the present invention. [Figure 6]Figure 6a shows a different angle view of the fan blower space heater of Figures 5a-5e in a first operating configuration. Figure 6b shows a different angle view of the fan blower space heater of Figures 5a-5e in a first operating configuration. Figure 6c shows a different angle view of the fan blower space heater of Figures 5a-5e in a first operating configuration. Figure 6d shows a different angle cross-sectional view of the fan blower space heater of Figures 5a-5e in a first operating configuration. Figure 6e shows a different angle cross-sectional view of the fan blower space heater of Figures 5a-5e in a first operating configuration. [Figure 7] Figure 7a shows a view from a different angle of a convective space heater according to another embodiment of the present invention. Figure 7b shows a view from a different angle of a convective space heater according to another embodiment of the present invention. Figure 7c shows a cross-sectional view from a different angle of a convective space heater according to another embodiment of the present invention. Figure 7d shows a view from a different angle of a convective space heater according to another embodiment of the present invention. Figure 7e shows a cross-sectional view from a different angle of a convective space heater according to another embodiment of the present invention. [Figure 8] Figure 8a shows views from different angles of an oil-filled radiator space heater according to another embodiment of the present invention, Figure 8b shows views from different angles of an oil-filled radiator space heater according to another embodiment of the present invention, Figure 8c shows views from different angles of an oil-filled radiator space heater according to another embodiment of the present invention, and Figure 8d shows cross-sectional views from different angles of an oil-filled radiator space heater according to another embodiment of the present invention. [Figure 9] Figure 9a shows views from different angles of an oil-filled radiator space heater according to another embodiment of the present invention, Figure 9b shows views from different angles of an oil-filled radiator space heater according to another embodiment of the present invention, Figure 9c shows cross-sectional views from different angles of an oil-filled radiator space heater according to another embodiment of the present invention, and Figure 9d shows views from different angles of an oil-filled radiator space heater according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0019] The exemplary embodiments described in the detailed description and claims are not intended to be limiting. Other embodiments may be used, and other changes may be made, without departing from the scope of the invention. Various embodiments are described. The specific embodiments are not intended as exhaustive or as limitations on the broader aspects discussed and claimed. Features described in connection with a particular embodiment are not necessarily limited to that embodiment and can be incorporated into any other embodiment. The protection afforded by the applicable doctrine of equivalents is maintained to its fullest extent.

[0020] Terms such as "up," "down," "top," "bottom," "left," "right," "inner," "outer," "vertical," "upstanding," etc. are used to describe the invention concisely 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 invention.

[0021] Referring to FIG. 1 , an electric space heater 1 is shown schematically. Various aspects of the heater are described in detail with reference to non-limiting examples. Other details will be apparent to those skilled in the art. In particular, those skilled in the art can incorporate aspects of known electric space heaters (including aspects not described) into the present invention. The electric space heater is an independent space heater in that it is independent of any central heating system; in some embodiments, the electric space heater is a portable heating device designed to heat a small area, or "space," rather than an entire room or building. In this embodiment, the space heater is also independent in that it does not rely on any other energy source (e.g., in the same way as a central heating radiator, which relies on heating from a central heater in a connected heated water circuit). While such a central heating system may have access to a powerful heater located in the circuit, an independent space heater does not have access to such a heater. Those skilled in the art can adapt the described embodiments to electric space heater types other than those described. As is known, these heater types can be used to directly heat the air surrounding the heater, to heat the ambient air via a heating fluid (such as oil in an oil-filled radiator), or to heat the ambient air via another medium such as a heating block, e.g., a ceramic heating block.

[0022] Conventional electric space heaters that heat ambient air are well known in the art. Air typically flows past or through such heaters. In some cases, the air to be heated flows past an electric element (e.g., in a fan-blower space heater), and in other cases, the electric heating element is contained within a housing along with a heating fluid, such as heating oil in an air-filled radiator, which heats the ambient air outside the housing case.

[0023] In this embodiment, the freestanding electric space heater 1 is a convection heater. In other embodiments, the heater may be a fan blower heater, or an oil-filled radiator, or any other type of electric space heater. The heater 1 includes a heater housing 2 arranged to house its components. In many cases, heaters of the present invention are required to be portable. In many embodiments, the present invention includes features (described in more detail below) that make the heater compact so that the heater can be easily transported and moved, even when the heater of the present invention includes novel components.

[0024] Heater 1 is configured to heat ambient air. Relatively cool air arrives at heater 1 (schematically represented by virtual input pipe 4), is heated, and then relatively hot air exits heater 1 into the ambient environment (represented by virtual pipe 6). These virtual pipes are included in the drawings solely to aid in the understanding of the invention; typically, a convection space heater generates airflow within a space due to the temperature difference between the heated and unheated air (as described above). In this embodiment, no physical pipelines are present.

[0025] Heater 1 comprises a first electric heating device including a first electric heating element 8 and a case 10, which is located within housing 2 and between inlet 4 and outlet 6 and is arranged to house electric heating element 8. Case 10 is configured to heat air passing through the heater and past case 10. The case is a protective case to protect exposed element 8 from wear and tear. In other embodiments, the case may be absent and the heating device is exposed.

[0026] In some embodiments, the electric heating device may comprise multiple electric heating elements.

[0027] In accordance with the present invention, the first electric heating element 8 is in communication with both a DC power source and an AC power source such that the first electric heating element 8 can be powered by either or both of the DC and AC power sources.

[0028] In embodiments in which the electric heating device includes multiple electric heating elements, some electric heating elements may be configured to be powered only by AC, some electric heating elements may be configured to be powered only by DC, or some electric heating elements may be configured to be powered by both AC and DC. As will be apparent to those skilled in the art, any combination of these options is possible. Average AC power demand on the grid tends to be lower than full-pelt or continuous AC use. Residential environments (where such heaters are frequently used) also tend to have lower peak AC usage. Therefore, the system of the present invention is less likely to cause electrical system failure or excessive heating of things like plug sockets (which could cause a fire). In some embodiments, the controller is configured to heat the electric heating device via a mix of AC and DC, or via only AC and only DC at different times or for different use cases, or any combination thereof. In this embodiment, the DC power source is in the form of a battery pack 20. The battery pack 20 is a component of the heater 1 and is also located within the housing 2. In other embodiments, the DC power supply may be located external to the heater.

[0029] In this example, the AC power source includes a mains power source 22 (also known as "utility power," "domestic power," "household electricity," "residential current," "power line," "household power," "wall power," "line power," "AC power," "city power," "street power," or "hydro power").

[0030] The heater also includes a controller 24 configured to control the distribution of power from the DC power supply 20 and the AC power supply 22 to the first heating element 8. The controller may be implemented in hardware or software, or a combination thereof, as will be apparent to those skilled in the art.

[0031] In some embodiments, the controller is computerized and configured to control the amount of heating provided to the ambient air based on or in response to any one or more control factors, including the capacity of the heating device, the capacity of the or each heating element, the amount of heating required, the air input temperature at an inlet point within the heater housing, the air output temperature at an output point within the heater housing, the air temperature at any predetermined point within the heater housing, the air temperature at any predetermined point outside the heater housing (e.g., within the space to be heated), the amount of heat capacity available from the first heating element, the instantaneous demand for heating, the forecasted demand for heating, and the flow rate of the air to be heated.

[0032] Additionally, in some embodiments, the fluid heater includes one or more sensors (not shown) configured to sense information related to one or more control factors and provide the control factor information to the controller. Some of the sensors are located inside the heater housing (e.g., to measure the air temperature or the flow rate of air or heated fluid within the heater). Some of the sensors are located outside the heater housing (e.g., to measure the air temperature or the air flow rate at a desired location outside the heater, such as in a room of a building). The controller operates in response to information from such sensors to direct the heating of the fluid by the electric heating device.

[0033] In some embodiments, the controller may have a memory (not shown) associated with it (integrally or separately), configured to store information about any one or more aspects of the system, such as historical or sensory information about any of the control factors, control factor information, sensory information from any of the sensors, desired output information (e.g., desired room temperature), etc. The controller can access information from the memory in known manner. The controller and memory may be implemented within standard computerized networks and systems.

[0034] In this embodiment, the controller 24 comprises a hardware thermostat controller and optionally a further GUI thermostat controller (not shown) to allow a user to easily input desired heating requirements and receive feedback regarding heating operation parameters in a known manner.

[0035] In this example, the controller 24 also includes an AC power adapter (not shown) configured to interact with the external AC power source 22 to provide AC power to the heating elements 8 in a desired power configuration. Although not present in this embodiment, in some embodiments a DC power adapter disposed between the DC power source and the heating elements is similarly configured to interact with the DC power source 22 to deliver DC power to the heating elements in a desired power configuration.

[0036] The controller is configured to consider many factors when controlling the allocation of power to the heating elements. In some cases (at any given time), it may be desirable to use only DC power, in other cases (at any given time), it may be desirable to use only AC power, and in other cases (at any given time), it may be desirable to use a combination of DC and AC power. Example scenarios are listed in the Overview section above, but other scenarios will be apparent to those skilled in the art.

[0037] The controller may be configured to control the relative allocation of power from the DC and AC sources taking into account any one or more of: the capacity of the heating device; the capacity of the or each heating element (e.g., the maximum safe load of a particular heating element (e.g., peak power or duration of continuous power supply)); the capacity of the or each power source; the instantaneous demand for heating (e.g., whether the heater has just been turned on or the or each heating has just been started from a cold state); the predicted demand for heating; and the instantaneous or predicted available supply type (e.g., is there DC battery capacity remaining or is there currently a high load on the AC grid). The controller may also be configured to provide a seamless switch from using primarily DC power to using primarily AC power, e.g., so that as the DC battery becomes depleted, the AC power supply gradually or suddenly switches off. The DC power source may take over while the power output remains approximately constant or at a desired level, or the DC power source may be gradually or suddenly utilized as a predicted or measured peak AC load time occurs or approaches. The controller may also control smart charging of the DC power source such that heating and charging levels (e.g., whether to charge aggressively / quickly or more slowly) are taken into account when controlling charging. In some embodiments, the DC power source is configured to simultaneously charge and power the electric heating device at the same time. If the DC power source comprises a battery pack with multiple cells, the controller may be configured to simultaneously use some cells of the DC power source to heat the electric heating device and charge some (or all) other cells of the DC power source.

[0038] In some embodiments, the first heating device may have a preferred power demand range, and the controller is configured to supply power within the preferred power demand range while varying the ratio of AC to DC power to the first heating element between 0:100 and 100:0 AC:DC. When the demand is fully or largely met by the AC power source, a relatively low or zero DC power source may be required. In some embodiments, the DC power source is sized such that 100% of the heating demand cannot be met by the DC power source alone. In other embodiments, a large DC power source is provided, allowing such a requirement to be met by the DC power source alone. Some embodiments are described later in this specification.

[0039] In this embodiment, the heater is a fully electric heater, i.e., the heat source is entirely electric. In other embodiments, the heater may be partially electric, e.g., partially electric and partially gas-powered, or partially electric and partially other combustible fuel-powered. Suitable combustible fuels may be combustible fluids such as natural gas, hydrogen gas, propane gas, methane gas, ethane gas, or butane gas, or suitable combustible oil, or suitable combustible solids or mulch such as wood chips or wood pellets, or any combination thereof. Thus, heating power may be provided by electrical (DC and AC) components or by more traditional combustion fuels. This can be useful for adding redundancy within a system or for efficient operation in environments where one or the other power source is insufficient. In some embodiments of the present invention, the combination of DC and AC power sources is large enough to provide all or nearly all of the power output of a typical heater as needed. In other embodiments, the combustible fluid may provide the majority of the power output, while the power source provides a supplemental heat effect. For example, a power source may be used because burning fuel alone can take a long time to heat a space, especially when the heater is first started. In some cases, this is because it is possible to heat a flammable fluid via a heating block (or the like), but it takes time (e.g., several minutes) to warm up from a cold state.

[0040] Referring to Figure 2, an electric space heater 31 according to another embodiment is shown schematically. Various aspects of the heater 31 will now be described in detail with reference to non-limiting examples. Other details will be apparent to those skilled in the art. In particular, aspects of known electric space heater systems (including aspects not described) can be incorporated into and used with the present invention by those skilled in the art.

[0041] In this embodiment, the freestanding electric space heater 31 is a convection heater. In other embodiments, the heater may be a fan blower heater, or an oil-filled radiator, or any other type of electric space heater. The heater 31 includes a heater housing 32 configured to house its components. In many cases, heaters of the present invention are desired to be portable. In many embodiments, the present invention includes features (described in more detail below) that make the heater compact so that the heater can be easily transported and moved, even when the heater of the present invention includes novel components.

[0042] Heater 31 is configured to heat ambient air. Relatively cool air reaches heater 31 (schematically represented by phantom inlet pipe 34), is heated, and then relatively hot air exits heater 31 into the ambient environment (represented by phantom pipe 36). These phantom pipes are included in the drawings solely to aid in the understanding of the invention; typically, a convection space heater generates airflow within a space due to the temperature difference between the heated and unheated air (as described above). In this embodiment, no physical pipelines are present.

[0043] Heater 31 comprises a first electric heating device including a first electric heating element 38 and a case 40, with case 40 located within housing 32 and between inlet 34 and outlet 36 and arranged to house electric heating element 38. The electric heating device in case 40 is configured to heat air passing through the heater and past case 40. The case is a protective case to protect exposed element 38 from wear and tear. In other embodiments, the case may be absent and the heating device is exposed.

[0044] In some embodiments, the electric heating device may comprise multiple electric heating elements.

[0045] In accordance with the present invention, the first electric heating element 38 is in communication with both a DC power source and an AC power source such that the first electric heating element 38 can be powered by either or both of the DC and AC power sources.

[0046] In embodiments where the electric heating device includes multiple electric heating elements, some of the electric heating elements may be configured to be powered only by AC, some of the electric heating elements may be configured to be powered only by DC, and some of the electric heating elements may be configured to be powered by both AC and DC, with any combination of these options possible, as would be apparent to one skilled in the art.

[0047] In this embodiment, the DC power source is in the form of a battery pack 50 that is part of the heater 31 and is also located within the housing 32. In other embodiments, the DC power source may be located external to the heater.

[0048] In this embodiment, the AC power source includes a mains power supply 52 .

[0049] The heater also includes a controller 54 configured to control the distribution of power from the DC power supply 50 and the AC power supply 52 to the first heating element 38. The controller may be implemented in hardware or software, or a combination thereof, as will be apparent to those skilled in the art.

[0050] In this embodiment, the controller 54 includes a hardware thermostat controller and, optionally, a further GUI thermostat controller (not shown) to allow a user to easily input desired fluid heating requirements and receive feedback regarding fluid heating operating parameters in a known manner.

[0051] In this embodiment, the controller 54 also includes an AC power adapter (not shown) configured to interface with the external AC power source 52 to deliver AC power to the heating element 38 in a desired power configuration.

[0052] The controller 54 also includes a DC-AC converter (not shown separately from the controller in the drawings) disposed between the DC power source and the heating elements and configured to interact with the DC power source 22 to convert DC to AC in a known manner before transmitting power to the heating elements in the desired power configuration.

[0053] In this embodiment, the controller is configured to control the combination of outputs from the AC and DC power sources to deliver only AC power to the heating element. The advantage of this feature is that the input circuitry to the heating element is simpler than if both AC and DC were supplied directly to the heating element (resulting in fewer circuit connections to the electric heating element, which in turn improves reliability, maintenance, and space savings).

[0054] In other embodiments, the controller may be configured to control a combination of outputs from the AC and DC power sources to achieve different goals.

[0055] In other examples, the heater may include an AC-DC converter (instead of a DC-AC converter). The AC-DC converter is disposed between the AC power source and the heating element and is configured to interact with the AC power source to convert AC to DC in a known manner before transmitting only DC power to the heating element in the desired power configuration. Again, an advantage of this feature is that the input circuitry to the heating element is simpler than if both AC and DC were supplied directly to the heating element. In this scenario, in some embodiments, the AC-DC converter may be disposed inside the heater housing 32, while in other embodiments, it may be disposed outside the heater housing.

[0056] The controller is configured to take into account a number of factors when controlling the allocation of power to the heating elements, which were discussed above in relation to the embodiment of Figure 1 and also apply to this embodiment.

[0057] The controller is configured to control the relative allocation of power from the DC and AC power sources, taking into account the factors discussed above in connection with the embodiment of FIG. 1, and also applies to this embodiment.

[0058] In some embodiments, the first heating element may have a preferred power demand range, and the controller is configured to supply power within the preferred power demand range while varying the ratio of AC to DC power to the first heating element within a range of AC:DC 0:100 to 100:0, as described above in connection with the embodiment of FIG. 1 .

[0059] In this embodiment, the heater is fully electric, i.e., the heat source is entirely electric. In other embodiments, the heater may be partially electric, e.g., partially electric and partially gas-powered, or partially electric and partially other combustible fuel-powered, where suitable combustible fuels may be natural gas, hydrogen gas, propane gas, methane gas, ethane gas, butane gas, suitable combustible oil, wood chips, or wood pellets, or any combination thereof. In this manner, some of the heating power may be provided by the electric (DC and AC) components, and some of the heating power may be provided by more traditional combustion fuels. This can be useful for adding redundancy within the system or can be used to operate efficiently in environments where one or the other power source is insufficient. In some embodiments of the present invention, the combined DC and AC power sources may be large enough to provide all or nearly all of the power output of a typical heater as needed.

[0060] Features of the controller and the manner in which power from AC and DC power sources is intelligently allocated when powering heating elements as described with reference to Figures 1 and 2 may be used in combination with the embodiments described below, and protection is particularly sought for any such combination(s).

[0061] Referring to FIG. 3, an electric space heater 100 similar to that described with reference to FIG. 1 is shown. Unless otherwise specified, the technical features are similar to those described with reference to the previous embodiments (e.g., with reference to FIG. 1 or FIG. 2). The heater 100 is used to heat air within a typical domestic room space. Various aspects of the heater and heater system are described in detail with reference to non-limiting examples. Other details will be apparent to those skilled in the art. In particular, aspects of known space heater systems (including aspects not described) can be incorporated and used in the present invention by those skilled in the art.

[0062] In this embodiment, heater 100 is a convection heater and includes a heater housing 102 for housing its components.

[0063] In this embodiment, the freestanding electric space heater 100 is a convection heater. In other embodiments, the heater may be a fan blower heater, or an oil-filled radiator, or any other type of electric space heater. The heater 100 includes a heater housing 102 configured to house its components. In many cases, heaters of the present invention are desired to be portable. In many embodiments, the present invention includes features (described in more detail below) that make the heater compact so that the heater can be easily transported and moved, even when the heater of the present invention includes novel components.

[0064] Heater 31 is configured to heat ambient air. Relatively cool air reaches heater 100 (schematically represented by phantom inlet pipe 104), is heated, and then relatively hot air exits heater 100 into the ambient environment (represented by phantom pipe 106). These phantom pipes are included in the drawings solely to aid in the understanding of the invention; typically, a convection space heater generates airflow within a space due to the temperature difference between the heated and unheated air (as described above). No physical pipelines are present in this embodiment.

[0065] The heater 101 comprises a first electric heating device. The first electric heating device includes a first electric heating element 108 and a case 110, which is located within the housing 102 and between the inlet 104 and the outlet 106 and is configured to house the electric heating element 108. The case 110 is configured to heat air passing through the heater and past the case 110. The case is a protective case to protect the exposed element 108 from wear and tear. In other embodiments, the case may not be present and the heating device is exposed.

[0066] In accordance with the present invention, the first electric heating element 108 is powered by a combination of DC and AC power sources of the type described with reference to Figure 1, although in alternative embodiments the combination of DC and AC power sources may be of the type described with reference to Figure 2 or related embodiments. For clarity, most of the common components shown in Figure 1 (e.g., the controller and its associated circuitry) are not reproduced in Figure 3.

[0067] In some embodiments, the electric heating device may comprise multiple electric heating elements.

[0068] In embodiments where the electric heating device includes multiple electric heating elements, some of the electric heating elements may be configured to be powered only by AC, some of the electric heating elements may be configured to be powered only by DC, and some of the electric heating elements may be configured to be powered by both AC and DC, with any combination of these options possible, as would be apparent to one skilled in the art.

[0069] In this embodiment, the DC power source is in the form of a battery pack 120, which is also located within the housing 102. In this embodiment, the heater is fully electric, i.e., the heat source is entirely electric. In other embodiments, the heater may be partially electric, e.g., partially electric and partially gas-powered, or partially electric and partially other combustible fuel-powered, where suitable combustible fuels may be natural gas, hydrogen gas, propane gas, methane gas, ethane gas, butane gas, or suitable combustible oil, solid, or mulch, or any combination thereof. Thus, heating power may be provided by the electric DC component or by more traditional combustion fuels. This can be useful for adding redundancy within the system or for efficient operation in environments where one or other power source is insufficient. In some embodiments of the present invention, the DC power source is large enough to provide all or nearly all of the power output of a typical heater as needed.

[0070] In this example, the DC power supply has a capacity of 0.25 kWh.

[0071] In general, the DC power supply capacity may be configured to significantly increase the maximum performance of the space heater and / or to allow the space heater to operate on the DC power supply with at least a reasonably useful power output for a reasonably useful period of time. Some exemplary configurations include: 2kW to 3kW convection heater with up to 1500W AC and up to 1500W DC (models range in capacity may include a 500Wh battery, a 750Wh battery, or a 1kWh battery. By way of example, a 500Wh battery may be used to provide 1kW AC and 1kW DC for 30 minutes, etc.) 2kW to 4kW oil-filled radiator - similar configuration and 750Wh to 2kWh or larger battery

[0072] Fan heaters (including a DC battery with 250Wh at 1.5kW, capable of running for up to 10 minutes) can be added to the 1.5kW AC heating for a total of 3kW. Powerful space heaters of the present invention may provide at least 400Wh and have a combined (AC+DC) peak output of 5kW to 6kW. In this embodiment, the battery pack 120 comprises a stack of batteries in a compact configuration.

[0073] In this example, the 0.25 kWh DC battery pack 120 includes 25 replaceable or rechargeable cylindrical cells, such as standard-sized 18650 type cells (18 mm diameter and 65 mm length), each with a capacity of approximately 10 Wh. In this example, the rechargeable cells are arranged in a 5 x 5 stack for compactness, and the entire stack can be removed from the battery pack 120 and recharged externally from the housing 102. In alternative examples, the stack may be configured differently, and other suitable stack configurations will be apparent depending on the available space in the battery pack. The stack is configured in a known manner to provide approximately consistent usage of each cell in the stack over time, such that the stack effectively operates as a single unit. In some examples, the DC power source can also be charged from a renewable heat source, such as solar or wind power, or a heat pump, or any other suitable source.

[0074] In other embodiments, the DC battery pack can be charged in situ, ie, without removing the cells from the housing 102, via a charging connection (not shown).

[0075] In some such embodiments, the DC power source is configured to simultaneously charge and power the electric heating device, the DC power source comprises a battery pack having multiple cells, and the controller is configured to simultaneously use some cells of the DC power source to heat the electric heating device and charge some (or all) other cells of the DC power source.

[0076] Charging of the battery pack is performed in this embodiment by an AC-DC converter (not shown), and in embodiments where charging is performed in situ, the heater further comprises an AC-DC converter disposed within its housing.

[0077] A typical 18650 type cell has a voltage of 3.6V. In this embodiment, the cells in pack 120 are arranged in series, i.e., the effective voltage is about 90V. The pack is well insulated. In other embodiments, the cells may be arranged in various ways, such as all in series (so that the maximum voltage in any single path is 3.6V) or multiple parallel paths with several cells in series, e.g., five parallel paths, each path having five cells (18V) in series.

[0078] In some embodiments, the cells may be configured to provide a voltage approximately the same as the AC input supply voltage, making it easier to combine AC and DC and easier to charge, for example in the UK a 240V battery pack may be provided.

[0079] In some embodiments, instead of a single battery pack, multiple battery packs or multiple stacks within a single battery pack are provided.

[0080] In some embodiments, the capacity of the DC power pack is at least 50 Wh, or optionally 100 Wh. Thus, a 400 W heater can support AC at 100 Wh for 15 minutes, or double that power for 15 minutes. There is no substantial limit to maximum capacity (industrially independent heaters of the present invention may have larger batteries). In some cases, the DC power source is configured to have an output power capacity of at least 200 W, and in other cases at least 400 W. The present invention provides significant power improvements compared to using AC-only electric heaters; for example, a 50 Wh DC power pack used with the present invention allows an additional 6 minutes of 500 W operation (e.g., from a standard power socket, a total output of 3490 W in the UK or 2900 W in the US (which, as mentioned above, is typically limited)). The larger the power pack capacity, the greater the power level improvement and even longer run time.

[0081] The heater 100 housing also uses its AC connection 130 to power small electronic components (which have relatively low power demands compared to the power required to heat the air during normal heater operation), such as a controller, adapter(s), switching circuitry, heater display screen, heater user interface, sensors, Wi-Fi, Bluetooth, sub-1 GHz communications, etc., LED lighting, and other standard space heater components. Other such components may include a thermal switch (sometimes referred to separately from a temperature sensor by some manufacturers), a thermostat, a thermocouple / PRT, a control PCB, a multimedia interface, power electronics for a power pack, and a fan (either a simple electric fan or, in some cases, a more complex fan combined with drive electronics). In some embodiments, this power may be provided by a renewable heat source, such as solar or wind power, or a heat pump, or any other suitable heat source. In some other embodiments, any one or combination of these small electronic components may be powered directly from a DC power source.

[0082] In this embodiment, heater 100 also includes a controller (not shown) configured to control any one or more of heating, battery charging, battery discharging, system requirements, and switching of the DC power supply as described with reference to the embodiment of FIG. 1.

[0083] The battery of the present invention generates some heat. Other electrical components of the heater also generate some heat. The inventors recognized the need for a compact, efficient, non-standard cooling system.

[0084] The heater 100 in this embodiment also includes a cooling system (not shown). The electronics (controller, switches, adapters, etc.) may become hotter than a typical heater due to the involvement of DC battery power, the extra switching required for intelligent use of the DC battery, and the operation of the controller and its associated circuitry due to the requirement for intelligent use of DC-v-AC.

[0085] In some embodiments, the heater includes a high-power switching module configured to efficiently switch high currents so that power can be varied across the same resistive electric heating element. This is particularly important in modes that provide a rapidly switching output that combines AC and DC to use less average AC power but maintain a stable overall combined power output of the heater. This feature allows for pulse width modulation within the control circuitry. The high-power switching module may be configured to switch 3, 5, 13, 15, 20 amps or more (e.g., 30 amps or more).

[0086] In embodiments that include a battery charging mechanism, the inventors have further discovered that heat generation within the battery charging system (specifically, the AC-DC converter battery charging system, which allows the voltage to charge the DC battery pack / cells) can be problematic. This type of battery charging system generates heat that is not present within the electric space heater system or heater housing. Therefore, a further advantage of some examples of the present invention is to use a cooling system (or provide an additional, separate cooling system) as a heat sink to also cool the battery charging mechanism. The battery charging mechanism cooling system can be particularly useful because it can (and should) charge even when the heating system is not on (i.e., when the heating system is not heating the space, e.g., overnight, or when it detects that a user has left the space (e.g., when a sensor senses that a person has left the room being heated)). The cooling system of the present invention allows the heating system to operate to remove heat during periods of charging only. The controller may be configured to cool the battery charging mechanism even when heating is not needed by forcing cool air through the heater (e.g., by operating a fan); for example, the controller may operate in response to predicting, being notified, or sensing that the battery charging system should be cooled (e.g., via feedback from a temperature sensor located near the battery charger or after the battery has been continuously charged for a threshold minimum period of time). This battery charging mechanism cooling functionality may be implemented using any of the described embodiments, including the battery charger, to create new embodiments of the present invention.

[0087] In some embodiments (e.g., where ambient air flow is responsible for cooling), when the heating system is operational (e.g., when heated air is demanded), then cooling occurs via the flow of heated cool air through any one, some, or optionally all of the controller, battery, battery charger, adapter(s), and any other control electronics. However, when the heating system is not operational, the present invention allows for operation of the charger cooling system (whether via ambient air flow or via its own dedicated refrigerant in its own dedicated refrigerant circuit) specifically for the purpose of cooling the battery charger. This feature may be particularly useful in embodiments of the present invention having a high-power charging system (which may be a larger battery or a smaller battery that can be rapidly charged, or any combination thereof).

[0088] In some embodiments, the cooling system uses a portion of the cold air that reaches the cold inlet 104 to cool the electronics, which may be quite hot (ideally intended to keep the electronic components well below 100°C). In some embodiments, elements of the cooling system include placing the cold air from the inlet 104 within the heater 100 adjacent to or near the components requiring cooling. This increases the overall efficiency of the heater and also allows the heater electronics to be more compact / simpler, as the need for full electronic efficiency with switching power is reduced.

[0089] The cooling system of some embodiments includes a refrigerant circuit having a closed refrigerant piping system (not shown) through which a refrigerant is pumped. The closed refrigerant piping system is configured to facilitate heat transfer between the refrigerant and a cold air inlet of a heater and to facilitate heat transfer between the refrigerant and battery cells or other components. This is achieved by routing the piping system in suitable locations to be in close proximity to any one or more of the heater component, the battery cells, and the cold air inlet.

[0090] In many embodiments, the DC power cells and electronic components are protected from the heat of the electric heating device. In some examples, the electric heating device is positioned above the DC power cells and / or electronic components to protect them (from rising hot air). In other examples, the DC power cells and / or electronic components may be positioned to the side of the heating element(s). In some examples, the DC power source and / or sensitive components may be positioned above the heating element(s), and in such examples, heat from the heating element may be deflected around the cell / PCB, etc., via, for example, one or more physical deflector panels, possibly heat-reflective deflector panels. Also, the housing only provides a barrier to direct line of sight, protecting against direct infrared heat from the heating element; therefore, in some examples, the DC power source and / or other sensitive components are positioned in a compartmentalized portion of the housing that is appropriately separated from the heating element(s).

[0091] In some embodiments, the housing 100 includes an access door positioned to allow access to the internal components of the heater (e.g., for maintenance or repair), and the DC power supply is positioned within or integral with the access door, which also confers overall compactness and ensures that the DC battery does not need to be further removed or manipulated to access the internal heater components (e.g., for repair / service).

[0092] In this embodiment, heater 100 also includes a thermal insulation layer or heat shield (not shown) located between the DC power supply and the first heating device and between the controller and the first heating device. The thermal insulation layer or heat shield may include any one or any combination of a gap, a gap filled (partially or completely) with a thermal insulating material, a gap filled (partially or completely) with an infrared reflective material, or a gap filled (partially or completely) with an insulator or low thermal conductivity material.

[0093] In some embodiments, the heat shield may include an associated heat shield cooling mechanism positioned to transfer heat from the heat shield region towards another area where it is safer to dissipate the heat, the cooling mechanism comprising any one or more of the following: A fluid material, such as air or water, that carries heat away from an area (e.g., a heat shield area) to a heat dissipation area (i.e., another area that is safer to dissipate heat than the heat shield area); Active cooling mechanisms such as Peltier elements (which actively move heat from one side to another, e.g., to an area that is safer to dissipate heat than the heat-shielded area); A cooling cabinet or block (similar to a typical refrigerator) located inside the heater and generally surrounding the DC power supply; An airflow mechanism, such as a blower, arranged to draw air from outside the housing or from inside the housing to provide the required cooling effect.

[0094] In a further embodiment (not shown), the heater comprises a hybrid electric-gas heater case instead of a case having only an electric heating element. In such an embodiment, multiple heating mechanisms are provided within the same sealed heater case chamber. One is an electric heating mechanism (similar to that described in connection with the other embodiments) and the other is a gas burner mechanism. The gas burner mechanism is of a known type. Instead of natural gas, the other mechanism may be a variety of fuel-fired burners (e.g., hydrogen gas, propane gas, oil). The electric heating mechanism may be in any suitable form. In this example, it is in the form of an electric heating element. The heater may be arranged to heat air within a space, in one example. An electric heating element or multiple such elements may be located anywhere within or around the burner case so that the air can be heated by either or both the gas and electric heating mechanisms. The heating element may be an electric wire capable of being heated by passing an electric current through it and may be appropriately positioned to transmit heat as needed (e.g., wrapped around a pipe or any other component within the burner case). In some embodiments, the power supply is configured to provide preheat when the hybrid heater is first turned on and when the combustible fuel alone needs assistance to bring the space up to a desired temperature. In some cases, this is because the combustible fluid may be heated via a heating block (or the like), which takes time (e.g., several minutes) to warm up from a cold state.

[0095] There may be a heat exchanger within the gas burner case. The heat exchanger is configured to concentrate heat from the combustion gases, the heated electric element(s), or both, into the air to be heated. The heat exchanger may be metallic or ceramic. In one embodiment, the heat exchanger may be in the form of one or more plates (e.g., metal plates) positioned in close proximity to the air to be heated. The electric heating element may be positioned between the plates. In another embodiment, there may be a block of suitable material (e.g., a ceramic block) positioned in close proximity to the air to be heated.

[0096] More specific embodiments of the present invention will now be described with reference to schematic diagrams illustrating some key elements of these embodiments. Other elements of the embodiments may not be shown or described, but will be apparent to those skilled in the art. In particular, all embodiments can function with any of the features described above (e.g., in connection with FIGS. 1, 2, or 3), and all such combinations are hereby disclosed. For example, tip or tip detection with auto-shutdown, various control factor options for the controller, various battery device capacity options, and various power supply balancing AC-v-DC options.

[0097] In some of these examples, the combined DC+AC power source is configured to increase the peak power of the electric heating device by at least 25%, in other examples by at least 50%, in other examples by at least 100% (i.e., approximately 100%, doubling the output), and in still other examples by significantly more than 100% compared to using AC alone.

[0098] Example 1: Fan Blower (Figs. 4a to 4d) The electric space heater comprises a fan blower space heater 400 configured to heat a space, such as a room. The heater has a housing 402 including legs 440 configured to provide a wide, stable support for placing the heater on a flat surface. The housing has an air intake opening 404 that allows air from the space to enter the housing, and an air output opening 406 that allows heated air to leave the housing and enter the space.

[0099] The heater comprises a first electric heating device, which includes a coiled electric heating element 408 configured to heat air flowing through or past its coils. The heater comprises a fan 480 configured to blow air heated by the heating element 408 into the space to be heated. In this embodiment (which may differ in other embodiments), the coiled heating element and the fan are both mounted coaxially relative to the housing so as to be linearly aligned with the openings of the inlet 404 and outlet 406. The fan is therefore also configured to draw air to be heated from the space toward the electric heating element.

[0100] The heating element 408 may be of any of the types previously described and is configured to be powered by a mains AC or DC power source, as previously described in connection with other embodiments.

[0101] The heater also includes power electronics 424, which includes a controller configured to control the distribution of power from the DC and AC power sources to the heating element in a manner similar to that described above in connection with the previous embodiment. The power electronics 424 also includes an AC power interface configured to interface with a mains AC power source. The power electronics are positioned below the first electric heating device so that undesired heating effects from the heating device on the power electronics are mitigated.

[0102] In this embodiment, the heater comprises a DC power source in the form of a battery pack 420 comprising an array of easily accessible rechargeable cells. The battery pack is positioned below the first electric heating device so that undesirable heating effects from the heating device to the battery pack are mitigated.

[0103] In this embodiment, the peak power is 400 W. In other embodiments, the peak power may be less, for example, for smaller cabin heater versions. In other embodiments, the peak power may be, for example, up to 3 kW for a domestic embodiment, or 10 kW or more for an industrial fan blower heater. Typical peak powers for space heaters according to the present invention are between 1500 W and 2000 W. Often, such space heaters have multiple heating settings; for example, in one embodiment, low and high settings provide peak powers of 1 kW and 3 kW, respectively.

[0104] The heater components and housing are configured to ensure that the airflow is isolated from the cell and electronics, as will be explained in more detail. Physically, the heat is always above the cell and electronics (hot air rises, etc.) to protect them.

[0105] The housing 402 is a compartmentalized housing 402 having two chambers: a first, upper chamber contains the heating element 408 and fan 480, and a second, lower chamber contains the battery pack 420 and power electronics 424 (including the controller and AC power interface). In this embodiment, the upper chamber is directly above the lower chamber. Each chamber is relatively closed. In this embodiment, the housing includes a separation wall 403 between the upper and lower chambers, which is configured to protect the battery pack and control electronics from direct infrared heat from the heating element by providing a barrier to direct line of sight. The location of the first chamber above the second chamber also ensures that convection heat from the heating element 408 does not undesirably affect the battery pack and control electronics 424 during use. Furthermore, the fan, electric heating element, and air inlet and outlet to and from the heater housing are aligned within their own chambers so that air is directed in a desired path that does not naturally pass through a second chamber (i.e., does not affect the battery or control electronics).

[0106] Example 2: Fan Blower (Figs. 5a to 5e, 6a to 6e) The electric space heater comprises a modular fan blower space heater 500 configured to heat a space, such as a room. For clarity, Figures 5a-5e show the space heater with its modules separated, while Figures 6a-6e show the space heater with its modules assembled into one operating configuration. Note that the modular space heater can also be assembled into different operating configurations, as described in more detail below.

[0107] The housing has an air intake opening 504 through which air from the space can enter the housing, and an air output opening 506 through which heated air can leave the housing and enter the space.

[0108] The heater comprises a first electric heating device, which includes a coiled electric heating element 508 configured to heat air flowing through or past its coils. The heater comprises a fan 580 configured to blow air heated by the heating element 508 into a space to be heated. In this embodiment (which may be different in other embodiments), the coiled heating element and the fan are both mounted coaxially relative to the housing so as to be linearly aligned with the openings of the inlet 504 and output 506. The fan is therefore also configured to draw air to be heated from the space toward the electric heating element.

[0109] The heating element 508 may be of any of the types previously described and is configured to be powered by a mains AC or DC power source, as previously described in connection with other embodiments.

[0110] The heater also includes power electronics 524 including a controller configured to control the distribution of power from the DC power source and the AC power source to the heating element in a manner similar to that described above in connection with the previous embodiment. The power electronics 524 also includes an AC power interface configured to interface with a mains AC power source. The power electronics are positioned below the first electric heating device so that undesired heating effects from the heating device on the power electronics are mitigated.

[0111] In this embodiment, the heater comprises a DC power source in the form of a battery pack 520 comprising an array of easily accessible rechargeable cells. The battery pack is positioned below the first electric heating device so that undesirable heating effects from the heating device to the battery pack are mitigated.

[0112] In this example, the present invention provides a 500Wh fan heater, which is a heating system with a peak output of 2.5kW from DC and a maximum of 2.5kW AC. This allows for a total output of 5kW. However, the heater can be controlled by the controller to operate in a low power mode providing 250W AC and 250W DC, in which case the battery pack will last a longer period of approximately 2 hours.

[0113] The heater 500 has a modular housing with three modules: a bottom module 502a that houses power electronics 524 and is configured to interface with an AC power source and has an air inlet opening 504 formed therethrough; a middle module 502b that is arranged to house a DC power source 520; and a top module 502c that is configured to house an electric heating element 508 and a fan 580 and has an outlet opening 506 formed therethrough. The bottom, middle, and top modules are configured to interdigitate with one another to form multiple operating configurations of the heater housing, as described below. In other embodiments, the modules may be coupled to one another by any suitable mechanism, including one or more of a slot fit, a clip fit, a friction fit, a threaded fit, or a bolt fit.

[0114] In this embodiment, the bottom module 502a includes a pedestal 540 configured to elevate the bottom of the heater so that the air intake openings can be on the bottom surface of the bottom module 502a that faces downward when in use and are formed in the bottom module 502a. The air intake openings are thereby formed through the bottom surface of the heater while being elevated above the surface on which the space heater rests. The air intake, DC power supply, heating element, fan, and air outlet are thereby aligned to provide an efficient and desired air flow path.

[0115] The pedestal also provides a wide, stable support for resting the bottom module on a flat surface.

[0116] In this embodiment, a mesh 550 is provided at the air output opening to enhance safe operation (by preventing large objects / fingers from reaching the heating element and fan) while allowing heated air to move freely away from the heater.

[0117] In this embodiment, the housing is a generally cylindrical housing, and each module of the housing has a corresponding contour to provide a smooth profile and a pleasing aesthetic appearance while allowing for efficient operation. The housing is elongated (to allow for desired alignment of the components, as described above).

[0118] Advantageously, multiple operating configurations of the modular heater are possible: the bottom module can be directly connected to the top module and also directly connected to the middle module; the top module can be directly connected to the top module and also directly connected to the middle module; and the middle module can be connected to the bottom module and the top module.

[0119] In a first operating configuration (as seen in Figures 6a-6e), all three modules can be used together to provide heating via AC and DC power sources.

[0120] In a second operating configuration (not shown), the bottom and top modules can be used together without the middle module to provide heating via AC power only.

[0121] The controller 524 is configured to recognize (e.g., via appropriate sensing mechanisms) which modules are connected in which operating configurations, and based on this recognition, the controller can appropriately control the power supply (AC only, or an intelligent combination of AC+DC) to the electric heating elements.

[0122] The battery cells can be charged without removing the pack from the mid-module, and the heater can operate in a second configuration, e.g., without the mid-module, while the battery pack is being recharged.

[0123] Advantageously, in the first operating configuration, the battery pack and control electronics are positioned upstream of the heating element within the airflow path defined by the fan. Thus, in use, relatively cool air flows past and is used to cool both the battery pack and the control electronics (which may generate unwanted heat during operation). Through this configuration, the air to be heated also receives some preheating before reaching the heating element, making the overall heating process more efficient.

[0124] Similarly, in a second operating configuration, the control electronics are located upstream of the heating element within the airflow path defined by the fan, with similar advantages.

[0125] Therefore, in this embodiment, no other cooling system is required. In other embodiments, the present invention provides separate cooling systems, for example, separate cooling systems for the electronics (controller, adapter, and / or battery charger) and the battery pack.

[0126] As with the other embodiments, the heat is physically above the cells and electronics (hot air rises, etc.) to protect the cells and electronics.

[0127] The combined housing 502a, 502b, 502c in this modular portable fan heater embodiment is approximately 20 cm in diameter and 35 cm in height. Other size and shape options will be apparent to those skilled in the art.

[0128] Example 3: Convection heater (Figures 7a-7e) The electric space heater comprises a convective space heater 700 configured to heat a space, such as a room. The heater has a housing 702, which includes a bracket 740 configured to facilitate secure mounting of the convective heater to a wall in a known manner. The housing has a series of openings along its bottom surface and a series of openings along its top surface, with the openings along the bottom surface acting as air intake openings 704 through which air from the space can enter the housing and the openings along the top surface acting as air output openings 706 through which heated air can exit the housing and enter the space. As previously described, air is heated by the convective heater, and the air rises, displacing cooler air from the space, creating a current of warm air that circulates throughout the space. This occurs through openings 704, 706.

[0129] The heater comprises a first electric heater comprising two nichrome electric heating elements 708 configured to heat air flowing through or past them. The heater does not comprise a fan in this embodiment, and natural convection drives the airflow of air heated by the heating elements 708 into the space to be heated.

[0130] The heating element 708 can be of any of the types described above and is configured to be powered by a mains AC or DC power source as described above in connection with other embodiments.

[0131] The heater also includes power electronics 724 including a controller configured to control the distribution of power from the DC and AC power sources to the heating element in a manner similar to that described above in connection with the previous embodiment. The power electronics 724 also includes an AC power interface configured to interface with a mains AC power source. The power electronics are located below the electric heating device so that undesired heating effects from the heating device on the power electronics are mitigated.

[0132] In this example, the heater includes a DC power source in the form of a battery pack 720 including five blocks of rechargeable cells. The battery pack is positioned below the first electric heating device so that undesirable heating effects from the heating device on the battery pack are mitigated. In this example, the controller includes a battery charging mechanism, and the battery pack is configured to be charged in situ via the power electronics.

[0133] In this embodiment, the convection heater is suitable for home use and has a peak power of 1 kW. In other home convection heater embodiments, the peak power may be between 500 W and 3 kW.

[0134] The heater components and housing are configured to ensure that the airflow is isolated from the cells and electronics, as will be explained in more detail below: the heat is always physically above the cells and electronics (hot air rises, etc.) to protect them.

[0135] The housing 702 is a compartmentalized housing 702 having two chambers: a first, upper chamber contains the heating element 708, and a second, lower chamber contains the battery pack 720 and power electronics (including the controller and AC power interface) 724. In this example, the upper chamber is directly above the lower chamber. Each chamber is relatively closed. In this example, the housing includes a separation wall 703 between the upper and lower chambers, which is configured to protect the battery pack and control electronics from direct infrared heat from the heating element by providing a barrier to direct line of sight. The first chamber also ensures that, during use, convection heat from the heating element 708 does not undesirably affect the battery pack and control electronics 724. Furthermore, because the electric heating element and the air inlet and outlet to and from the heater housing are aligned within their own chambers, air is directed in a desired path that does not naturally pass through the second chamber (i.e., does not naturally affect the battery or controller electronics). In this embodiment, in particular, wall 703 does not seal the upper and lower chambers from each other, leaving an air flow path to allow air to move freely from the inlet to the outlet.

[0136] Additionally, the convection heater includes a separate heat shield 705 to shield the DC power supply and control electronics from heat from the electric heating element. The heat shield allows air to flow through it, allowing free movement from the air inlet to the outlet. In this embodiment (see FIG. 7e), the heat shield includes a cross plate below the electric heating element and above the battery and control electronics. The cross plate does not abut against the inner wall of the heater housing, allowing some air to flow through it. In other embodiments, the cross plate may alternatively or additionally have openings formed therethrough to allow air to pass through. In this embodiment, the two heat shield plates 703, 705 function well together, with the upper heat shield plate 703 being warm enough to radiate heat, and the lower secondary heat shield plate 705 positioned to shield the battery and other components in the lower chamber from heat radiated from the upper heat shield plate. Alternative configurations of the heat shield (eg, non-plate) will be apparent to those skilled in the art.

[0137] In other embodiments (not shown), the convection heater may alternatively or additionally have an insulating layer or heat shield, or both, between the battery (and / or power electronics components) and the housing 702 (which may conduct unwanted heat from the heated area (near the heating element) toward the battery and / or power electronics). The same types of insulating layers (e.g., air gaps) or heat shields as described above with respect to other embodiments can be used. The insulating layer may include the housing itself, with built-in layers (e.g., strips of insulating material such as ABS plastic or nylon) between sections of the housing (e.g., metal portions); in such cases, the metal housing surrounding the heating element(s) may become and remain hotter than the metal housing surrounding the battery; for example, the housing around an upper chamber may become much hotter than the housing around a lower chamber.

[0138] Example 4: Oil-filled radiator (Figures 8a-8d) The electric space heater comprises an oil-filled radiator space heater 800 arranged to heat a space, such as a room. As previously mentioned, air is heated by the radiator heater, which radiates heat outward, warming the surrounding air. In Figure 8a, arrows 804, 806 are shown to illustrate this process.

[0139] The heater has a two-part housing, the first part of the housing is a radiator housing 802a that contains a first electric heating device 808 and a heating fluid, in this case oil. The second part of the housing is an electrical component housing 802b that contains a battery pack 820 and power electronics 824. These features are described further below. The radiator housing has metal fins as shown in the drawings. The housing also includes feet 840 arranged to provide a stable support for placing the heater on a flat surface in a known manner.

[0140] The heater comprises a first electric heater, which comprises an electric heating bar 808 configured to heat oil flowing through the radiator housing 802a. In this embodiment, the heater does not comprise a fan; metal fins on the radiator housing heat up due to the hot oil inside and radiate heat into the space to be heated. During use, the oil at the top of the radiator is warmer than the oil at the bottom (hot fluid rises). The oil sinks to the bottom after losing heat to the surroundings through the fins. The electric heating bar 808 is positioned near the bottom of the housing 802a. The cold oil heats up, rises, and the process repeats.

[0141] The heating element 808 may be of any of the types previously described and is configured to be powered by a mains AC or DC power source, as previously described in connection with other embodiments.

[0142] The heater also includes power electronics 824, which includes a controller configured to control the distribution of power from the DC and AC power sources to the heating element in a manner similar to that described above in connection with the previous embodiment. The power electronics 824 also includes an AC power interface configured to interface with the mains AC power source. The power electronics are located in a separate portion of the housing, i.e., electrical component housing 802b, to the side of the electric heating device so that undesired heating effects from the heating device on the power electronics are mitigated.

[0143] In this example, the DC power source is in the form of a battery pack comprising six easily accessible modules, each comprising a block of cells conducting in series with one another. The battery modules are arranged in a 3x2 configuration in this example for compactness. Each module can be easily removed for recharging.

[0144] The battery pack is located in another portion of the housing, electrical component housing 802b, to the side of the electric heating device so that unwanted heating effects from the heating device on the battery pack are mitigated.

[0145] In particular, the two housing portions 802a, 802b are configured to securely connect to one another in use such that the contents of the electrical component housing 802b are thermally shielded from the contents of the radiator housing 802a.

[0146] Furthermore, the two parts 802a, 802b of the housing are arranged to be securely connected to each other so that, in use, the power electronics 824 is located close to the electric heating device, thereby minimizing the amount of wiring required between the two (which has advantages such as reduced assembly and wire routing).

[0147] The two parts of the housing 802a, 802b can be easily separated if necessary, for example the electrical component housing 802b can be easily removed to allow access to the battery and power electronics for charging or replacement / repair.

[0148] In some embodiments, the controller includes a battery charging mechanism, and the battery pack is configured to be charged in situ via the power electronics.

[0149] In this embodiment, the heater 800 is suitable for domestic use and has a peak power of 1 kW. In other domestic embodiments, the peak power may be between 800W and 2.5kW.

[0150] Example 5: Oil-filled radiator (Figures 9a-9d) In this embodiment, the space heater includes an oil-filled radiator 900 similar to that of Example 4. For clarity, similar features will not be repeated. Radiator 900 differs from radiator 800 in that its battery 920 and power electronics 924 are located within an electrical component housing 902b beneath its radiator housing 902a. Instead of feet, the radiator is supported by four wheels 940 arranged for stable support on flat ground, making it easily portable.

[0151] Example 6: Infrared Radiant Space Heater (not shown) Infrared radiant space heaters are within the scope of the present invention. Those skilled in the art will appreciate that such heaters operate on similar principles to those described above and may, in one embodiment, have a peak power of 300 W. Other embodiments may have a peak power of at least 1 kW, and perhaps 3 kW.

[0152] Example 7: All-Electric Patio Space Heater (not shown) All-electric patio space heaters are within the scope of the present invention. Those skilled in the art will appreciate that such heaters operate on similar principles to those described above and may, in one embodiment, have a peak power of 1500 W. Other embodiments may have a peak power of at least 5 kW, and perhaps 10 kW.

[0153] Example 8: Hybrid Gas-Electric Patio Heater Space Heater (not shown) Hybrid gas-electric patio space heaters are within the scope of the present invention. Those skilled in the art will appreciate that such heaters operate on similar principles to those described above and may, in one embodiment, have a peak power of 1000 W. Other embodiments may have a peak power of at least 3 kW, and perhaps 7 kW.

[0154] Example 9: Hybrid Combustible Fuel-Electric Spot Space Heater (not shown) Hybrid combustible fuel-electric spot space heaters are within the scope of the present invention. Those skilled in the art will appreciate that such heaters operate on similar principles to those described above and may, in one embodiment, have a peak power of 500 W. Other embodiments may have a peak power of at least 2 kW, and perhaps 5 kW.

[0155] Various modifications can be made to the present invention without departing from the scope of the invention.

[0156] Optionally, in some embodiments in which the heater comprises two (or more) heating elements, the controller may be configured to power a first heating element only via a DC power source and a second heating element only via an AC power source. This feature reduces the need for more complex circuitry and therefore reduces the risk of circuit failure. Furthermore, if one power source fails, the other power source will still operate.

[0157] In another embodiment, the heater comprises an industrial-sized furnace air heater (similar to the portable space heater described above, but larger).

[0158] In either embodiment, the AC may be disconnected (or unavailable, for example during a power outage) and the heater may operate solely from the DC power source.

[0159] In some examples, the DC battery capacity may be at least 0.1 kWh of power, such as about 0.2 kWh, or about 0.5 kWh, or about 1 kWh. The peak power output may be about 3 kW DC combined with 3 kW AC in some embodiments.

[0160] Two or more heating elements may be provided per heater case.

[0161] For any embodiment described as being solely electric, those skilled in the art will understand that it may alternatively be provided in the form of partly electric and partly combustible fuel.

[0162] Any embodiment may include a DC power interface configured to receive a DC power source, the DC power interface configured to receive two or more types of DC power sources, such as any combination of Ni-MH battery cell packs, Ni-Cd battery cell packs, and Lithium battery cell packs, or a composite pack including any combination of these types of cells. A supercapacitor can be used instead of or in addition to a conventional DC battery pack to provide the DC power source.

[0163] Any of the embodiments including a DC power cell may include a safety shut-off mechanism configured to shut off the cell from powering the electric heating element. The safety shut-off mechanism may comprise a master switch or an automatic master switch, and in some embodiments, the safety shut-off mechanism comprises a contactor. Advantageously, this provides a safe and simple DC switching mechanism. Particularly in the case of floor-standing or portable space heaters, the safety mechanism is activated when the heater is detected to be tilted or lifted off a flat or stable surface. The space heater may include one or more feet positioned to rest stably on a flat surface.

[0164] Such a safety mechanism (fall detection mechanism) is particularly important to the present invention because if the heater is turned upside down, heat can seep into the battery cells, posing a more significant hazard than traditional space heaters.

[0165] Heaters within the scope of the present invention can be provided by incorporating electric heating element(s), or batteries, or both, into existing electric space, gas (or other combustible fuel), or gas-electric hybrid heaters, along with a control mechanism (e.g., control electronics and / or software) for controlling the amount of heating provided by DC, AC, or a combination thereof.

[0166] Space heaters of the present invention can be more powerful and efficient, as described above. Such embodiments are particularly suited for incorporating electric heating capabilities into existing AC electric or gas heaters. For example, an electric heating element may be coated on, coated within, sprayed into, housed within, wrapped around, partially or wholly embedded in, or otherwise associated with a duct section at or near the duct section, i.e., at its exit from the combustible fuel burner case, its entrance to the burner case, or both. The heating element may be powered by DC, AC, or a combination thereof. In some embodiments, a battery, such as a large battery of the type described above, along with a control mechanism (e.g., control electronics and / or software) can be attached to the burner case to control the amount of heating provided by the electric heating element(s) to the combustible fuel source. When attached to an AC electric heater, a DC power pack may be added along with appropriate control electronics to enable balanced use of DC and AC depending on demand and / or supply requirements.

[0167] In any, all, or some embodiments, a battery charging mechanism is provided that is configured to charge the DC power source, and the battery charging mechanism is configured to charge the DC power source taking into account and responsive to any one or more of: current DC power cell charge levels, or the capacity of each power source, instantaneous demand for heating, forecasted demand for heating, instantaneous or forecasted available power source type, and household demand, regional demand, national demand, international demand, or any combination thereof. Typically, the battery pack is charged during low demand times, for example, overnight or during the day (when the controller is informed that AC demand (not necessarily from heating alone) is typically low, or when the controller learns that grid power demand is low).

[0168] In any of the described embodiments, the or each heating element may be any element that emits heat when an electric current is passed through it, such as any resistive wire or wire array that emits heat when an electric current is passed through it. These elements include, for example, but are not limited to: Thin films (polyimide on conductive metal), Ceramic wire (ceramic sheath with nickel-chromium-aluminum embedded in it) Bare wire (nickel, nichrome, Kanthal, Stellite, etc.), Insulated wire (e.g. nichrome with silicone jacket), aluminium-coated resistance elements (e.g. die-cast) with the resistance element arranged so as to be electrically insulated from the aluminium casing; Mineral insulated wire - copper sheath / nichrome, cupronickel / inconel, steel sheath / nickel, inconel sheath / nickel wire and all kinds of mixtures thereof (elements may be drawn to size or manufactured to finished size, etc.); an insulator, typically Al2O3 or MgO, · Winding elements sandwiched between plain wires, spiral (helical) wires, and busbar wires.

[0169] Suitable alternative materials using similar construction will be apparent to those skilled in the art.

[0170] In any example where a single heating element is described, the single heating element may be replaced by one or more different heating elements, as would be apparent to one skilled in the art. For example, one or more of the electric heating elements may comprise an electrically conductive heating element coating on any one or more of the heater's inner surface, heater exterior, or any other component. One or more of the electric heating elements may comprise an induction heating element, for example, so that the electric heating element can be powered by induction (without direct contact).

[0171] In some cases, multiple separate electric heating elements are arranged to heat the air in separate sections of the heater. In some embodiments, multiple separate sections of heating elements are provided within the heater, and each section may be controlled together or separately, for example, to provide different levels of heating at different section locations. This is effective in situations where different heating levels may be appropriate at different heater locations. For example, it may be desirable to provide different heating levels at different sections of the air path, such as at the initial start of heating when air is first heated from a cold state, e.g., when heating is first requested, the initial input air may be particularly cold so that more heating may be provided at the beginning of the air path than at the end of the air path.

[0172] In some of these embodiments, the element may be completely embedded within the heater housing such that no part of the element emerges or protrudes from the duct (eg, there are no external electrical connection points).

[0173] In some embodiments where the heating elements are provided in discrete zones (rather than continuously along the entire length of the heater housing), the gaps between the discrete zones can be formed by masking the gaps on the housing surface (e.g., with a spray mask) during the coating / spraying process.

[0174] In some embodiments, the present invention provides a single housing space heater having an electric heating element configured to be powered by both a large DC power source and an AC power source with an on-board controller and controller cooling system. The inventors have recognized that the components of this type of system have significantly different cooling needs.

[0175] In some embodiments, the controller may be configured to provide power conservation algorithms, such as switching to powering the electric heating elements exclusively via AC power when DC power is unavailable (e.g., when the battery level is low or zero). The controller is programmed to ensure that some minimum threshold of DC capacity always remains, for example, to allow for high-power heating start-up from cold conditions when actually needed, or to conserve the AC grid during very busy times. This feature can be selectively activated or deactivated by the user via a user interface that sends commands to the controller. In some embodiments, the minimum threshold of DC capacity may be 5% of the total battery capacity to be maintained in the reservoir.

[0176] In some embodiments, the present invention provides a space heater that achieves the safe provision of an easily replaceable modular power pack within the heater housing. The power pack is of sufficient capacity to provide the heating load for a typical domestic dwelling space via DC power for a reasonable period of time, e.g., at least 5 minutes or at least 10 minutes. A power pack of this size is safely located within the housing using a heat shield as described above. The battery charger cooling mechanism may comprise or include separate or distinct cooling mechanisms for the controller and battery cooling mechanisms, as they may often be activated at different times than the controller and battery cooling mechanisms.

[0177] In some cases, there may be multiple cooling mechanisms, for example, at least one cooling mechanism associated with the controller and / or other heater power electronics, at least one cooling mechanism associated with the battery, and at least one cooling mechanism associated with the battery charger.

[0178] In some examples, the cooling system may be a passive cooling system configured to transfer heat away from the component to be cooled (such as heater electronics, a DC power supply, or a battery charger, or any combination thereof) (instead of or in addition to the cooling systems described above). A passive cooling system may not include a flowing fluid. A passive cooling system may include a thermal heat sink (e.g., an aluminum block) with natural convection fins for heat dissipation into the environment. A passive cooling system may include a relatively large thermal mass, such as a heater housing.

[0179] Space heaters are generally portable, but can also be mounted to a surface such as a room wall. This is usually done using an appropriate mounting bracket. Depending on the type of space heater, it may be desirable to leave an air gap between the wall of the space heater and the surface to which it is mounted to allow for a safe flow of air.

[0180] In some embodiments, the heater includes an AC port for powering other devices and / or a USB port for powering other devices or wireless charging.

[0181] In some embodiments, the heater may be configured to operate in a camping mode, and it may be useful to implement the fan version described above, or any other embodiment as a portable camping tent heater.

[0182] In many embodiments, the present invention can provide a significant power increase compared to using an AC-only electric heater, for example a 50Wh DC power pack used in the present invention allows for an additional 500W of operation for 6 minutes (e.g. total output from a standard power socket is 3490W in the UK or 2900W in the US (which as mentioned above is normally limited)). Combining a larger capacity power pack with a greater increased power level provides longer run times.

[0183] In some embodiments, any one or more of the controller, AC power adapter, DC-AC converter, and AC-DC converter are located close to the first electric heating device (e.g., within 50 cm, or within 15 cm, or within 10 cm, or within 2 cm). This reduces the amount of wiring required and simplifies assembly. It also reduces the possibility of electrical interference, thus providing more efficient operation.

[0184] In any embodiment, the space heater controller may comprise a hardware thermostat controller and, optionally, a further graphical user interface thermostat controller.

Claims

1. An electric space heater, a first electric heating device configured to be powered by both an AC power source and a DC power source; a controller configured to control the distribution of power from the DC power source and the AC power source to the first electric heating device; A space heater.

2. 10. The space heater of claim 1, wherein the DC power source has a capacity of at least 0.05 kWh, optionally at least 0.1 kWh, optionally at least 0.25 kWh.

3. 3. A space heater according to claim 1 or 2, wherein the AC power source comprises a mains AC power source, and wherein the combined peak power of the DC power source and the AC power source is at least 25%, optionally at least 50%, and further optionally at least 100% greater than the peak mains AC power source alone.

4. 4. A space heater according to any one of claims 1 to 3, further comprising the DC power supply, and optionally a DC power supply charging mechanism configured to recharge the DC power supply.

5. 5. The space heater of claim 1, further comprising a cooling system configured to cool any one or more of the controller, the DC power supply, and the DC power supply charging mechanism.

6. 6. A space heater according to any one of claims 1 to 5, wherein, in use, the first electric heating device is disposed above the DC power supply, the controller, and optionally, when dependent on claim 4, the DC power supply charging mechanism.

7. 7. A space heater according to any one of claims 1 to 6, comprising a thermal insulating layer or heat shield located between the DC power source and the first electric heating element, and optionally between any one or more of the controller, the DC power source charging mechanism, both the controller and the DC power source charging mechanism, and the first electric heating element.

8. 8. A space heater according to any preceding claim, wherein the AC power source comprises an AC power adapter configured to interface with an external AC power source, such as a mains AC power source.

9. A space heater according to any one of claims 1 to 8, a DC-AC converter disposed between the DC power source and the first electric heating device such that the first electric heating device is configured to receive only AC power from either the AC power source, the DC power source, or both; an AC-DC converter disposed between the first electric heating device and the AC power source such that the first electric heating device is configured to receive only DC power from either the AC power source, the DC power source, or both; A space heater.

10. 10. A space heater according to any preceding claim, wherein the controller is configured to control a combination of outputs from the AC power source and the DC power source.

11. 11. A space heater according to any one of claims 1 to 10, wherein the controller is configured to vary the ratio of AC to DC power to the first electric heating device, optionally by controlling switching between an AC only power mode and a DC only power mode.

12. 12. The space heater according to claim 1, wherein the controller: powering the first electric heating device using only the DC power source when a heating boost is required and only the AC power source when steady, continuous heating is required; or using the DC power source to power the first electric heating device when it is determined that the local AC grid may be overloaded; or Both A space heater configured to:

13. 13. A space heater according to any one of claims 1 to 12, wherein the first electric heating device includes a single electric heating element configured to be powered by both the AC power source and the DC power source.

14. 14. A space heater according to any one of claims 1 to 13, wherein the first electric heating device comprises a plurality of electric heating elements, such as a first electric heating element configured to be powered only by the AC power source and a second electric heating element configured to be powered only by the DC power source.

15. 15. A space heater as described in any one of claims 1 to 14, further comprising a heater housing configured to house the first electric heating device, optionally the heater housing having an inlet for atmospheric air to enter the heater housing and an outlet for heated air to exit the heater housing, optionally the inlet being on a bottom surface of the heater housing, the space heater further comprising a pedestal configured to elevate the inlet above a surface on which the space heater rests in use, optionally the pedestal being part of the heater housing.

16. 16. The space heater of claim 15, further comprising guide means arranged to guide air along a desired flow path between the inlet and the outlet, optionally the guide means comprising a fan system, and further optionally the fan system configured to guide air from outside the heater housing into the heater housing and direct the air towards the DC power source, the fan system further configured to guide the air after it has passed through the DC power source towards the first electric heating device and subsequently to the outlet.

17. 17. The space heater of claim 15 or 16, wherein the heater housing is configured to house any one or more of the DC power supply, the controller, the cooling system, the DC power supply charging mechanism, the AC power adapter, the DC-AC converter, the AC-DC converter, and the fan system.

18. 18. A space heater according to any one of claims 15 to 17, comprising an elongated electric heater, wherein the DC power source, the controller, the first electric heating device and the outlet are configured in a linear fashion, and optionally the fan system is also configured to be aligned with the DC power source, the first electric heating device and the outlet.

19. 19. The space heater of any one of claims 1 to 18, comprising a modular space heater comprising: a bottom module configured to interface with the AC power source; a middle module configured to house the DC power source; and a top module configured to house the first electric heating device, wherein the bottom module, the middle module, and the top module are configured to connect to one another via any one or more of a slot fit, a clip fit, a friction fit, a threaded fit, and a bolt fit to form the heater housing.

20. 20. The space heater of claim 19, the bottom module is configured to connect directly to the top module and also to connect directly to the middle module; the upper module is configured to connect directly to the upper module and also to connect directly to the middle module; the middle module is configured to connect to the bottom module and the top module; As a result, in a first in-use configuration, all three modules can be used together to provide heating via the AC power source and the DC power source, and in a second in-use configuration, the bottom module and the top module can be used together without the middle module to provide heating via only the AC power source, resulting in a space heater.

21. 21. A space heater according to any preceding claim, further comprising a radiator housing filled with a heating fluid such as oil, the first electric heating device being, in use, located inside and adjacent a bottom of the radiator housing and configured to heat the heating fluid.

22. 22. A space heater according to claim 21, wherein the DC power supply, in use, is located below the first electric heating device.

23. 23. A space heater as claimed in claim 21 or 22, wherein the DC power source is located outside, optionally below or to a side of, the radiator housing, and optionally the DC power source comprises an attached battery pack configured to attach to the radiator housing to form the space heater.

24. 24. A space heater according to any one of claims 21 to 23, wherein the radiator housing is configured to be attached to the heater housing, and optionally the radiator housing is positioned above the heater housing in use.

25. 25. A method of operating a space heater according to any one of claims 1 to 24, comprising controlling the distribution of power from said DC power source and said AC power source to said first electric heating device, optionally controlling said distribution of power only by either said DC power source or said AC power source at any given moment.

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