FLUID-FILLED RADIATOR WITH EXTERNAL HEATING ELEMENT

Abstract

----- FLUID-FILLED RADIATOR WITH EXTERNAL HEATING ELEMENT The invention relates to an electric radiator (100) comprising a housing (102), one face of the housing (102) constituting the front panel (103) of the electric radiator (100), a heating element (104) disposed inside the housing (102), and a control device (105) for controlling the heating of the heating element (104), characterized in that the front panel (103) is a closed hollow body made of thermally conductive material, the hollow body forming within the front panel (103) a self-contained container filled with heat transfer fluid, the heating element (104) being mounted opposite the internal face, known as the heat transfer face (103a), of the front panel (103) to transfer heat to the heat transfer fluid in the container. Figure to be published: Figure 2

Description

Title of the invention: FLUID RADIATOR WITH EXTERNAL HEATING ELEMENT

[0001] The invention relates to the field of heating, in particular electric heating, and concerns a fluid radiator with an external heating element.

[0002] Among existing radiators, a particular distinction is made between so-called fluid-filled radiators, which consist of a hollow structure filled with a heat transfer fluid heated by a heating element, called an immersion heater, immersed in the fluid within the hollow structure. The heating element, located at the bottom of the radiator, first heats the fluid, which then circulates by convection to distribute the heat throughout the structure. The structure then dissipates the heat into the air.

[0003] A distinction is also made between so-called "dry" radiators, which consist of a casing closed by a front panel and in which a heating element is placed. The heating element is positioned so as to heat the front panel. The front panel is often metallic, made from sheet steel or aluminum, or sometimes made of ceramic, glass, resin, stone, or any other temperature-resistant material. An air inlet is provided at the bottom of the casing to allow fresh air to enter, and an air outlet is provided at the top of the casing to allow the air heated by the heating element to escape by convection.

[0004] Fluid-filled radiators have the advantage, thanks to the circulation of the fluid, of having a very homogeneous temperature across all the radiator's external surfaces. This allows for the generation of gentle heat without hotter surfaces that can produce dry air with significant localized convection and a risk of scalding. The fluid's thermal inertia can also offer the advantage of producing stable heating because the heat stored in the fluid is released slowly.

[0005] However, fluid-filled radiators with immersed heating elements do not provide immediate heat because it takes time for the fluid to heat up.

[0006] "Dry" radiators, on the other hand, provide more responsiveness because the heating element heats up quickly and is in direct contact with the air.

[0007] However, it is difficult to heat the facade uniformly. It is common practice to create, on the heating element, zones with varying degrees of emissivity to partially radiate heat onto the facade and thus avoid hot spots, but this solution has the consequence of increasing the temperature of the heating element.

[0008] The objective is therefore to find a solution that allows both good heating responsiveness and gentle, even heat on the front, resulting in better thermal performance.

[0009] The invention proposes to overcome the drawbacks of existing radiators by providing an electric radiator with a front panel, which is in the form of a closed hollow body made of a thermally conductive material. The hollow body forms a self-contained container filled with a heat transfer fluid inside the front panel. The heating element is located inside a housing and is mounted opposite the inner face of the front panel to transfer heat to the heat transfer fluid in the container by radiation, while simultaneously heating the airflow passing through the radiator by convection. The fluid contained in the container is also heated by conduction at the fluid / solid interface. The fluid circulates by convection within the front panel, which has the effect of uniformizing the surface temperature. Since the heating element is outside the fluid container and in direct contact with the air, a portion of the power is rapidly used to heat the air.The power dissipated by radiation is used to heat the fluid.

[0010] The object of the invention is therefore an electric radiator comprising a casing having a lower air inlet and a upper air outlet, one face of the casing constituting the front of the electric radiator, a radiant heating element disposed inside the casing and a control device for controlling the heating of the heating element, characterized in that the front is a closed hollow body made of thermally conductive material, the hollow body forming inside the front a self-contained container filled with heat transfer fluid, the heating element being mounted opposite the internal face, known as the heat transfer face, of the front to transfer heat to the heat transfer fluid in the container by radiation and being disposed in the airflow between the lower air inlet of the casing and the upper air outlet of the casing to heat the airflow by convection.

[0011] The radiator according to the invention therefore exhibits good responsiveness, thanks to the electric heating element which heats the airflow passing through the radiator casing by convection, and also offers the advantages of so-called fluid-filled radiators, namely uniform surface temperature and thermal inertia, due to the presence of a front panel filled with fluid that can circulate within the panel by convection and is heated by radiation from the radiant heating element. The heating element thus has a dual role: to heat (indirectly) by radiation the fluid in the panel and to heat (directly) by convection the air passing through the radiator. It is therefore essential that air can circulate within the radiator around the heating element, and in particular between the heating element and the panel. The heating element is not immersed in the fluid container: the heating element is external to the fluid.

[0012] It is understood that at least one sealed opening can be provided on the facade to allow, if necessary, the change of fluid in the facade.

[0013] According to one embodiment, the container is one of a single-compartment container and a container with several isolated compartments.

[0014] According to one embodiment, the single-compartment container is formed of several chambers connected by a fluid communication manifold. A single chamber is thus formed, with a single fluid, facilitating the change of fluid in the front panel if necessary.

[0015] According to one embodiment, the surface area of ​​the heating element facing the thermal transfer face of the facade represents at least 30% of the surface area of ​​the facade.

[0016] Optimal heat transfer between the heating element and the facade is thus established. The invention is not limited in this respect, and a person skilled in the art will be able to size the heating element according to the expected performance of the radiator, the type and volume of the heat transfer fluid.

[0017] According to one embodiment, the heating element is mounted in the lower part of the housing to transfer heat to the lower part of the thermal transfer face of the front panel.

[0018] Heating the lower part of the facade makes it possible to facilitate the convection movements of fluid in the facade.

[0019] According to one embodiment, the thickness of the container's envelope is between 5 mm and 50 mm.

[0020] According to one embodiment, the facade is made of one of steel and aluminum.

[0021] According to one embodiment, the heat transfer fluid is one of water, optionally with added ethylene glycol or propylene glycol, an oil and a mixture of oils.

[0022] According to one embodiment, the heat transfer fluid comprises one or more types of fillers among the conductive fillers, such as graphene, metallic fillers and carbon-based fillers.

[0023] According to one embodiment, the heating element is spaced at least 5 mm from the front panel, in order to allow the air passing through the radiator to be heated by convection.

[0024] To better illustrate the object of the present invention, particular embodiments will now be described, by way of example and not limitation, in connection with the attached drawings.

[0025] On the drawings:

[0026] [Fig.l] is a schematic view of an electric radiator according to the prior art.

[0027] [Fig.2] is an exploded schematic view of a fluid-filled radiator with a heating element external according to a first embodiment of the invention.

[0028] [Fig.3] is a schematic cross-sectional view representing the fluid radiator with external heating element of the [Fig.2].

[0029] [Fig.4] is a schematic exploded view similar to [Fig.2] of a fluid radiator with an external heating element according to a second embodiment of the invention.

[0030] [Fig.5] is a diagram showing the temperature distribution obtained with a radiator according to the invention, on the inner face and on the outer face of the facade.

[0031] Figure 1 illustrates the prior art for an electric radiator 1, comprising a housing 2 partially closed at the front by a front panel 3, in which a heating element 4 is placed, visible behind the cutaway view of the front panel 3 in Figure 1. The heating element 4 is arranged to heat the front panel 3 by radiation. The heating element 4 is in the form of a metal sheet 4a (aluminum or cast iron) in which two longitudinal channels 4b are formed, through which an electric heating element (not shown) passes to form a central section between the two channels 4b and a lateral fin on each of the two channels 4b. The front panel 3 is often metallic, made from sheet steel or aluminum, or sometimes made of ceramic, glass, resin, stone, or any other temperature-resistant material.An air inlet 6, in the form of a grille formed at the base of the housing 2, is provided in the lower part of the housing 2 to allow fresh air to enter, and an air outlet 7 is provided in the upper part of the housing 2 to allow hot air heated by convection by the heating element 4 to escape. A control device 5 is located in the upper part of the housing 2 to control the heating of the heating element 4, via any conceivable human-machine interface, for example a control button 5a. The heating element 4 heats up rapidly and is in direct contact with the air, which allows heat to be supplied quickly by convection of the air coming from the grilles 6.

[0032] Figures 2 and 3 represent a radiator 100 according to a first embodiment of the invention.

[0033] The radiator 100 comprises a housing 102 with an open front face, the front 103 of the electric radiator 100 closing this front face of the housing 102, a heating element 104 disposed inside the housing 102 and a control device 105 for controlling the heating of the heating element 104, and openings and grilles 106 and 107 in the lower and upper parts of the housing 102, analogous to the openings and grille 6 and 7 described in connection with [Fig.1] and constituting respectively an air inlet and an air outlet for the air passing through the radiator. As with the heating element 4 described in connection with [Fig.1], the heating element 104, in this embodiment, is in the form of a metal plate 104a through which two longitudinal channels 104b pass, each channel 104b being traversed by a heating electrical resistance (not shown).The heating element 104 is fixed to the housing 102 by means of screws (not shown) inserted into holes 104c formed through the heating element 104, which screws then fix into the bottom of the housing 102. The front panel 103 is a closed hollow body made of thermally conductive material, in particular steel or aluminium, the hollow body forming inside the front panel 103 a . self-contained container filled with heat transfer fluid, the heating element 104 being mounted opposite the internal face 103a, known as the heat transfer face, of the facade 103 to transfer heat to the heat transfer fluid in the container formed by the facade 103.

[0034] The thickness of the container's envelope may in particular be between 5 mm and 50 mm, without the invention being limited in this respect.

[0035] The heating element 104 is of the radiant type and is spaced from the inner face 103a of the facade 103 by at least 5 mm, in order to allow an airflow between the inner face 103a of the facade 103 and the heating element 104 between the air inlet 106 and the air outlet 107, which airflow is heated by convection by the heating element 104.

[0036] The radiator 100 has good responsiveness thanks to the electric heating element 104 and also has the advantages of so-called fluid radiators, namely uniformity of surface temperature and thermal inertia, by the presence of a front 103 filled with fluid that can circulate in the front 103 by convection.

[0037] The container formed by the facade 103 is a single-compartment container or a container with several isolated compartments. If necessary, the single-compartment container is formed of several chambers connected by fluid communication via a manifold 109. In the embodiment of [Fig. 2], the front panel 103 consists of seven independent blades 108, connected by fluid communication via a manifold 109 to which the blades 108 are attached, for example by welding. The manifold 109 is fixed to the lower part of the blades 108 and communicates fluidly with the blades 108, generally by means of one or more openings formed between each blade 108 and the manifold 109. A rounded cutout 102a can be formed in the housing 102 to accommodate the manifold 109 when the front panel 103 is mounted on the housing 102. A single space is thus formed, with a single fluid, facilitating the change of fluid in the front panel 103 if necessary.It is understood that at least one sealed opening (not shown) can be provided on the facade 103 to, if necessary, introduce the heat transfer fluid into the facade 103 and allow the heat transfer fluid to be changed in the facade 103.

[0038] The surface of the heating element 104 facing the inner face 103a of the facade 103 represents at least 30% of the surface of the facade 103, thus allowing optimal heat transfer between the heating element 104 and the facade 103.

[0039] The heating element 104 is mounted in the lower part of the housing 102 to transfer heat to the lower part of the heat transfer face 103a of the front panel 103.

[0040] Heating the lower part of the facade 103 makes it possible to facilitate the convection movements of fluid in the facade 103.

[0041] The temperature of the inner face 103a of the thermal transfer of the facade 103 is not very uniform because the heating element 104 only radiates over a limited area of ​​the facade 103. Thanks to the thermal conductivity of the heat transfer fluid circulating in the facade 103, the temperature of the external face of the facade 103 is relatively homogeneous over its entire height, by convection inside the facade 103.

[0042] Various heat transfer fluids can be used within the framework of the present invention. Water is preferably used, as it has the advantage of being an inexpensive heat transfer fluid with good heat capacity and thermal conductivity.

[0043] The water may optionally be additively treated with ethylene glycol or propylene glycol to prevent freezing and to increase the boiling point of the heat transfer fluid.

[0044] Oils can also be used. They generally have a lower heat capacity than water, which allows the front panel 103 to heat up more quickly but reduces the inertia of the radiator 101. Their lower thermal conductivity does not allow for temperature uniformity as good as with water as the heat transfer fluid.

[0045] The facade 103 will not be completely filled with heat transfer fluid, an air space being provided to support the changes in volume of the heat transfer fluid in the facade 103 with temperature variations.

[0046] The thermal conductivity of the fluid can be improved by adding conductive fillers, such as graphene, or any other metallic or carbon-based filler, or even mixtures of fillers of different types.

[0047] As can be seen in [Fig.3], the heating element 104, once mounted in the housing 102, is not glued to the inner face 103a of the front panel 103, but is positioned opposite and at a distance from it to heat it by convection, the openings 106 and 107 in the lower and upper parts of the housing 102 facilitating the circulation of air by convection inside the housing 102.

[0048] The heating element 104 is mounted opposite the internal face, known as the heat transfer face 108, of the front panel 103 to transfer heat to the heat transfer fluid 107 in the container.

[0049] The facade 103 is a closed hollow body made of thermally conductive material, the hollow body forming inside the facade 103 an autonomous container filled with heat transfer fluid 107, the heating element being mounted opposite the internal face, known as the heat transfer face 108, of the facade to transfer heat to the heat transfer fluid in the container.

[0050] The surface of the heating element 104 in relation to the heat transfer face 108 of the facade 103 represents at least 30% of the surface of the facade 103, thus allowing optimal heat transfer between the heating element 104 and the facade 103.

[0051] The heating element 104 is mounted in the lower part of the housing 102 to transfer heat to the lower part of the heat transfer face 103a of the front panel 103.

[0052] Heating the lower part of the facade 103 makes it possible to facilitate the convection movements of fluid in the facade 103.

[0053] The temperature of the internal heat transfer face 103a of the facade 103 is not very uniform because the heating element 104 radiates only over a limited area of ​​the facade 103. Thanks to the thermal conductivity of the heat transfer fluid circulating inside the facade 103, the temperature of the external face of the facade 103 is relatively homogeneous over its entire height by convection inside the facade 103.

[0054] Figure 4 represents a fluid radiator with an external heating element according to a second embodiment of the invention.

[0055] Elements with the same structure as the first embodiment shall have the same reference number increased by 100, and shall not be described in further detail here if they have the same structure as in the first embodiment.

[0056] The difference between the second embodiment and the first embodiment lies in the fact that the facade 203 is formed from a single blade 208, forming a single chamber containing the heat transfer fluid, with a collector 209 in the lower part of the blade 208 to facilitate the circulation of the heat transfer fluid within the blade 208. The container formed inside the blade 208 is a single-compartment container consisting of a single chamber, with a single fluid, facilitating the change of the fluid in the facade 203 if necessary. As with the first embodiment, at least one fluid filling / change port (not shown) is provided for filling the facade 203 and changing the heat transfer fluid if necessary.

[0057] As with the first embodiment, the heating element 204 is of the radiant type and is spaced from the inner face 203a of the facade 203 by at least 5 mm, in order to allow an airflow between the inner face 203a of the facade 203 and the heating element 204, between the air inlet 206 and the air outlet 207, which airflow is heated by convection by the heating element 204.

[0058] Figure 5 illustrates the temperature uniformity obtained with a radiator according to the invention, on the inner face of the front panel on the left and on the outer face of the front panel on the right. It is thus possible to observe, in particular, that while the temperature is not uniform on the inner face—specifically, a warmer, darker area appears in the central part corresponding to the location of the heating element—the temperature on the outer face is uniform along the entire height of the fins.

Claims

Demands

1. Electric radiator (100; 200) comprising a casing (102; 202) having a lower air inlet (106; 206) and an upper air outlet (107; 207), one face of the casing (102; 202) constituting the front (103; 203) of the electric radiator (100; 200), a radiant heating element (104; 204) disposed inside the casing (102; 202) and a control device (105; 205) for controlling the heating of the heating element (104; 204), characterized in that the front (103; 203) is a closed hollow body made of thermally conductive material, the hollow body forming inside the front (103; 203) a self-contained container filled with heat transfer fluid, the heating element (104; 204) being mounted opposite the internal face known as the heat transfer face (103a; 203a) of the facade (103; 203) to transfer heat to the heat transfer fluid in the container by radiation and being disposed in the airflow between the lower air inlet (106;206) of the housing (102; 202) and the upper air outlet (107; 207) of the housing (102; 202) to heat the airflow by convection.;

2. Electric radiator (100; 200) according to claim 1, characterized in that the container is one of a single-compartment container and a container with several insulated compartments.

3. Electric radiator (100) according to claim 2, characterized in that the single-compartment container is formed of several chambers (108) connected in fluid communication by a manifold (109).

4. Electric radiator (100; 200) according to any one of claims 1 to 3, characterized in that the surface of the heating element (104; 204) opposite the heat transfer face (103a; 203a) of the front (103; 203) represents at least 30% of the surface of the front (103; 203).

5. Electric radiator (100; 200) according to any one of claims 1 or 4, characterized in that the heating element (104; 204) is mounted in the lower part of the housing (102; 202) to transfer heat to the lower part of the heat transfer face (103a; 203a) of the front (103; 203).

6. Electric radiator (100; 200) according to any one of claims 1 to 5, characterized in that the thickness of the container's casing is between 5 mm and 50 mm.

7. Electric radiator (100; 200) according to any one of claims 1 to 6, characterized in that the front panel (103; 203) is made of one of steel and aluminum.

8. Electric radiator (100; 200) according to any one of claims 1 to 7, characterized in that the heat transfer fluid is one of water, optionally with added ethylene glycol or propylene glycol, an oil and a mixture of oils.

9. Electric radiator (100; 200) according to any one of claims 1 to 8, characterized in that the heat transfer fluid comprises one or more types of fillers among conductive fillers, metallic fillers and carbon-based fillers.

10. Electric radiator (100; 200) according to any one of claims 1 to 9, characterized in that the heating element (104; 204) is spaced at least 5 mm from the front.

Images