US20160123627A1

US20160123627A1 - Heating appliance comprising a phase-change material

Info

Publication number: US20160123627A1
Application number: US14/896,526
Authority: US
Inventors: Alexandre Leblanc; Jean-Louis Morard
Original assignee: Muller et Cie SA
Current assignee: Muller et Cie SA
Priority date: 2013-06-07
Filing date: 2014-06-09
Publication date: 2016-05-05
Also published as: RU2684040C2; WO2014195512A1; RU2015155248A; EP3008397A1; CA2914827C; CA2914827A1; EP3008397B1; JP6634010B2; FR3006750A1; FR3006750B1; CN105393062A; JP2016520791A; RU2015155248A3

Abstract

A heating appliance includes a frame and a heating element. The frame has a casing and a rear face demarcating an internal volume of the frame. The rear face is configured to be secured to a wall that is substantially vertical. The heating element is placed in the internal volume of the frame. The casing of the heating appliance includes a phase-change material.

Description

This invention relates to a heating appliance comprising a phase-change material. The field of the invention is home heating.
Electric heating appliances comprising a frame with a rear face secured to the vertical wall of a room and a casing comprising a radiating element with a radiating front, heated from a rear face by a heating element such as for example a heating cable or a resistor that has been screen printed on film are known in the prior art.
When they are operating, the casings of these appliances can reach high surface temperatures, particularly temperatures that can expose the user to the risk of scorch. These heating appliances are more specifically dangerous when the lower part of the casing is easily accessible by very young children.
Solutions are known from the prior art to ensure that the temperature at the surface of the casing of such appliances does not exceed a maximum limit value. For example, known heating appliances are designed with lower maximum power ratings or fitted with electromechanical devices that degrade their maximum power rating to a lower rating, so as to obtain a lower temperature at the surface of the casing.
However, these solutions are not satisfactory, the first one requiring to design the heating appliances specifically for such a use, and the other presenting a risk for the user in case of the electronic devices malfunction.
Conventionally, the electricity supply of such heating appliances is based on the use of thyristors controlled by regulation devices. These thyristors operate like rapid-action switches, the opening and closing cycles of which control the electricity supply of the heating element.
But thyristor opening and closing cycles can occur several times a minute, leading to significant overheating of the thyristors, which can damage them. As a result, the thyristors need to be subsequently cooled. Such a problem particularly occurs when the heating appliance is stabilized at a temperature.
The cooling of thyristors by heat conduction using a heat sink is known, followed by convection cooling with air flowing around the thyristors inside the heating appliance. Immersing the thyristors in a liquid that evaporates upon contact with them and then condenses upon contact with a cold surface placed at a distance from the thyristors is also known. The energy accumulated by the thyristors can thus be carried away.
However, these solutions have several drawbacks. For example, the use of a heat sink does not make it possible to cool the thyristors sufficiently, and the heat sink tends to be fouled up by dust, which makes it less efficient. The use of fluid to cool the thyristors has the drawback of being particularly expensive and polluting, and requires the use of a complex sealed system.
Today, the development of electrical heating appliances aims to improve the comfort of users. In particular, designers are seeking to obtain heating appliances that heat rapidly but cool down very slowly.
Several solutions are available in the prior art. For example, the use of an element with high thermal inertia at the rear of the appliance is known, in addition to a radiating element with low thermal inertia. Thus, the element with high thermal inertia heats and cools very slowly, while the radiating element heats and cools very rapidly. However, that solution has the drawback of having a radiating front that cools as soon as the radiating element ceases to be heated. Another solution consists in using an inert inertial material for the radiating element, such as lave stone or glass, rated to provide medium thermal inertia.
However, this solution is only a compromise between high and low thermal inertia, and does not make it possible to obtain a heating appliance that heats rapidly but cools very slowly.
This invention is aimed at solving one or more of these technical problems, by remedying the drawbacks of the prior art.
More precisely, this invention relates to an electrical heating appliance comprising:

- a frame with a casing comprising a phase-change material and a rear face suitable for being secured to a wall that is substantially vertical, wherein the casing and the rear face demarcate an internal volume of the frame;
- a heating element placed in the internal volume of the frame.

A phase-change material is a material that is capable of accumulating energy at a substantially constant temperature, by changing its physical status.
Preferably, the casing comprises a radiating element with a radiating front, heated by the heating element, wherein the phase-change material is placed in the radiating element.
In a first embodiment of the invention, a phase-change temperature Tφ of the phase-change material is slightly higher than a maximum temperature Tmax permitted for the casing.
Such a heating appliance offers the advantage, if the appliance malfunctions, of slowing down the rise in temperature of the casing, so as to limit the risk of burns to the user.
In a second embodiment of the invention, a phase-change temperature TφA of the phase-change material is substantially equal to a required temperature TvA of the radiating front.
Such a heating appliance is particularly advantageous when the heating of the radiating element is regulated by thyristors. Indeed, such an appliance makes it possible to activate the thyristors less frequently, thus limiting their heating.
In this embodiment, the radiating element can advantageously comprise a second phase-change material with a phase-change temperature Tφ that is slightly higher than a maximum temperature Tmax permitted for the casing.
In a third embodiment of the invention, a phase-change temperature TφB of the phase-change material is slightly lower than a required temperature TvB of the radiating front.
Such a heating appliance offers the benefit of heating rapidly but cooling slowly, thus improving the user's comfort.
In this embodiment, the radiating element can advantageously comprise a second phase-change material with a phase-change temperature Tφ that is slightly higher than a maximum temperature Tmax permitted for the casing, and/or a third phase-change material with a phase-change temperature TφA that is substantially equal to a required temperature TvA of the radiating front.
In one embodiment of the invention, the radiating element forms a sealed container comprising several compartments, within which the phase-change material or materials are placed, wherein the compartments are arranged so as to form at least one channel connecting a rear face of the radiating element with the radiating front. In an alternative, the compartments are further arranged so as to form at least one channel placed substantially parallel to the radiating front.
Such a heating appliance offers the benefit of ensuring good thermal conductivity by the radiating element, from its rear face to the radiating front.

This invention will be better understood by reading the description below and examining the accompanying figures. The latter are provided for guidance and do not in any way limit the invention. The figures show:

FIG. 1: a schematic sectional side view of a heating appliance according to one embodiment of the invention;

FIG. 2: a change in the temperature of a phase-change material depending on the energy received;

FIG. 3: a schematic sectional side view of a heating appliance according to an embodiment of the invention other than that presented in FIG. 1;

FIG. 4: a change in the front temperature of a heating appliance over time, according to the prior art;

FIG. 5: a schematic sectional side view of a heating appliance according to an alternative of the embodiment presented in FIG. 3;

FIG. 6: a change in the front temperature of a heating appliance over time, according to the embodiment of the invention presented in FIG. 3.

FIG. 7: a schematic sectional side view of a heating appliance according to an embodiment of the invention other than those shown in FIGS. 1 and 3;

FIG. 8: a change in the front temperature of a heating appliance over time, according to the embodiment of the invention presented in FIG. 6;

FIG. 9: a schematic sectional side view of a heating appliance according to an alternative of the embodiment presented in FIG. 6.

FIG. 1 shows a heating appliance 100 according to a first embodiment of the invention.
The heating appliance 100 comprises a frame 101. The frame 101 has a rear face 102 that is suitable for being secured to a substantially vertical wall. The frame 101 also comprises a casing 103. The rear face 102 and the casing 103 together demarcate an internal volume 104 of the frame 101 that accommodates a heating element 105.
The casing 103 has a maximum permitted temperature Tmax. The maximum temperature Tmax is a temperature beyond which the appliance 100 presents a risk for a user, particularly a risk of scorch. The maximum temperature Tmax is for example standardized. The maximum temperature Tmax is for example entered in a data memory of a regulating device (not shown) of the device 100.
In one embodiment of the invention, the heating element 105 heats the air flowing through the appliance 100 by convection. The heating element 105 is placed near the rear face 102 of the frame 101. The heating element 105 is for example a heating resistor.
In the example presented in FIG. 1, the casing 103 comprises a radiating element 106 with a radiating front 107. The radiating element 106 is heated by the heating element 105. The heating element 105 is placed so as to heat the radiating element 106 substantially evenly.
In an embodiment of the invention (not shown), the casing 103 comprises several radiating elements 106, each with a radiating front 107 and a heating element 105. The radiating elements 106 are arranged so that the radiating fronts 107 of the radiating elements 106 together form a front of the appliance 100. The casing 103 comprises a phase-change material 109. The material 109 is for example paraffin, alcohol, silica gel, molten salt or salt hydrate. In the example presented in FIG. 1, the phase-change material 109 is particularly placed in the radiating element 106.
The phase-change material 109 has a phase-change temperature Tφ. In a preferred embodiment of the invention, the phase-change temperature Tφ is that of a solid/liquid-liquid/solid phase change. In one alternative, the phase-change temperature Tφ is that of a liquid/gas-gas/liquid phase change.
The change in the temperature Tm of the phase-change material 109 during a solid/liquid-liquid/solid phase change depending on the energy E received by it is described in FIG. 2. When the material 109 is in the solid phase, its temperature Tm is below the phase-change temperature Tφ. When the material 109 is in the solid phase, the energy E received by the material 109 leads to an increase in its temperature Tm. When the temperature Tm of the material 109 reaches the phase-change temperature Tφ, the material 109 simultaneously has a solid phase and a liquid phase. Consequently, the additional energy E that the material 109 receives is accumulated in the material 109, with no rise in its temperature Tm. The temperature Tm of the material 109 is stabilized at the phase-change temperature Tφ.
Then, after a certain quantity of energy E is received, the material 109 only has a liquid phase and its temperature Tm starts rising again. The change in the temperature Tm of the phase-change material 109 during a liquid/gas-gas/liquid phase change depending on the energy E received by it is similar.
In the example presented in FIG. 1, the material 109 is placed inside a sealed container 111 forming the radiating element 106.
The container 111 is for example in metal or plastic. In another exemplary embodiment, the container comprises material with a cellular structure. In one alternative, the material 109 is used to soak another porous solid material. The porous solid material is preferably a composite material. The material 109 that soaks the composite material is for example paraffin used to soak ceramic or molten salt encapsulated in polymer balls.
In the example presented in FIG. 1, the heating element 105 is placed against a rear face 108 of the radiating element 106. The heating element 105 is for example a resistor that has been screen printed on plastic film or a heating cable. In one alternative, the heating element 105 is embedded in the phase-change material 109 inside the container 111.
In the example presented in FIG. 1, the phase-change material 109 is selected so that its phase-change temperature Tφ is slightly higher than the maximum temperature Tmax of the casing 103. ‘Slightly higher’ means that the difference between the phase-change temperature Tφ and the maximum temperature Tmax does not exceed 30° C.
In that way, if the temperature of the casing 103 exceeds the permitted maximum temperature Tmax till it reaches the phase-change temperature Tφ of the material 109, the material 109 changes phases, thus stabilizing for a certain period the temperature of the casing 103 at the phase-change temperature Tφ. If the appliance 100 overheats, the rise in the temperature of the casing 103 is thus retarded, and the risks for the user are limited.
FIG. 3 shows a heating appliance 100A according to a second embodiment of the invention.
The heating appliance 100A comprises a frame 101A. The frame 101A has a rear face 102A that is suitable for being secured to a substantially vertical wall. The frame 101A also comprises a casing 103A. The rear face 102A and the casing 103A together demarcate an internal volume 104A of the frame 101A that accommodates a heating element 105A.
The casing 103A comprises a radiating element 106A with a radiating front 107A. According to one embodiment of the invention, the radiating element 106A is covered with a honeycomb plate placed at a distance from the radiating front 107A. The radiating element 106A is heated by the heating element 105A. The heating element 105A is placed so as to heat the radiating element 106A substantially evenly. 9
According to an embodiment of the invention (not shown), the casing 103A comprises several radiating elements 106A, each with a radiating front 107A and a heating element 105A. The radiating elements 106A are arranged so that the radiating fronts 107A of the radiating elements 106A together form a front of the appliance 100A.
The heating element 105A is connected to a switch 110A. Preferably, the switch 110A is a TRIAC, that is to say a triode for alternating current. The TRIAC 100A comprises a combination of two thyristors.
When it is operating, the TRIAC 110A opens and closes cyclically. When the TRIAC 110A is closed, the heating element 105A is supplied with electricity. When the TRIAC 110A is open, the heating element 105A is not supplied with electricity. According to an embodiment of the invention, the opening and closing times of the TRIAC 110A are equal. In one alternative, the opening and closing times of the TRIAC 110A are not equal.
The TRIAC 110A is regulated by a regulating device (not shown) of the device 100A. The regulating device comprises a microprocessor, a data memory, a program memory and at least one communication bus. The regulating device is connected by an input interface to one or more probes that measure a temperature Tp of the room in which the appliance 100A is installed. The regulating device is also connected by the input interface to an electronic clock. The regulation device is connected by an output interface to the TRIAC 110A.
After the device 100A has been started up and the room temperature Tp has reached a set temperature Tc, the regulating device starts up the TRIAC 110A, so as to maintain the room temperature Tp at the set temperature Tc. The set temperature Tc is for example pre-recorded in the data memory of the regulating device. The TRIAC 110A then opens and closes at a regular time interval Δt. The time interval Δt is for example pre-recorded in the data memory of the regulating device. The time interval Δt is determined so that the temperature Tf of the radiating front 107A is substantially constant in spite of the opening and closing cycles of the TRIAC 100A.
FIG. 4 shows the change over time t of the temperature Tf of the radiating front of a heating appliance of the prior art comprising a TRIAC as described above, during a phase when the temperature of the heated room Tp is held at the set temperature Tc. The greyed zones below the curve represent the time during which the TRIAC is closed. The time interval of an opening and closing cycle is short, so that the temperature Tf of the radiating front is substantially constant. That time interval may for example range from 30 to 60 s.
The casing 103A comprises a phase-change material 109A. The material 109A is for example paraffin, alcohol, silica gel, molten salt or salt hydrate. In the example presented in FIG. 3, the phase-change material 109A is more precisely placed in the radiating element 106A.
The phase-change material 109A has a phase-change temperature TφA. In a preferred embodiment of the invention, the phase-change temperature TφA is that of a solid/liquid-liquid/solid phase change. In an alternative, the phase-change temperature TφA is that of a liquid/gas-gas/liquid phase change. The behavior of the phase-change material 109A is equivalent to that represented in FIG. 2 described above.
In the example presented in FIG. 3, the material 109A is particularly placed inside a sealed container 111A forming the radiating element 106.
The container 111A is for example in metal or plastic. In another exemplary embodiment, the container comprises material with a cellular structure. In an alternative, the material 109A is used to soak another porous solid material. The porous solid material is preferably a composite material. The material 109A that soaks the composite material is for example paraffin used to soak ceramic or molten salt encapsulated in polymer balls.
In the example presented in FIG. 3, the heating element 105A is placed against a rear face 108A of the radiating element 106A. The heating element 105A is for example a resistor that has been screen printed on plastic film or a heating cable. In an alternative, the heating element 105A is embedded in the phase-change material 109A inside the container 111A. In another alternative presented in FIG. 5, the heating element 105A is a resistive wire, and the container 111A comprises a compartment 115A in which is placed the resistive wire 105A embedded in electrically insulating and thermally conductive material 116A, for example magnesia, and one or more other compartments 117A in which the phase-change material 109A is placed. The use of a honeycomb plate 118A covering the radiating element 106A is particularly adapted to this last alternative.
In the example presented in FIG. 3, the phase-change material 109A is selected so that its phase-change temperature TφA is substantially equal to a required temperature TvA of the radiating front 107A. The required temperature TvA is for example substantially equal to the temperature Tf of the radiating front 107A, when the room temperature Tp has reached the set temperature Tc.
In that way, near the required temperature TVA, the phase-change material changes phases and the rise or drop in the temperature of the radiating front 107A is slowed down. The radiating front 107A can thus be held at a temperature that is substantially constant, with a time interval Δt that is increased in relation to the time interval in the prior art represented in FIG. 4, therefore allowing the less frequent activating of the TRIAC 110A and thus the limited heating of the thyristors. FIG. 6 shows the change over time t of the temperature Tf of the radiating front 107A of the appliance 100A during a phase when the temperature Tp of the heated room is held at the set temperature Tc. The greyed zones below the curve represent the time during which the TRIAC 110A is closed. FIG. 6 illustrates the decrease in the frequency of the opening and closing cycles of the thyristor 110A allowed by the use of the phase-change material 109A in the casing 103A of the appliance 100A with a variation of the temperature Tf of the radiating front 107A around the required temperature TvA identical to that of FIG. 4.
The second embodiment of the invention can advantageously be combined with the first embodiment of the invention. The radiating element 106A then comprises a second phase-change material 109 with a phase-change temperature TφA that is slightly higher than a maximum temperature Tmax permitted for the casing 103A.
Thus, the appliance 110A offers both the benefits relating to the use of the phase-change material 109A and the benefits relating to the use of the phase-change material 109.
FIG. 7 shows a heating appliance 100B according to a third embodiment of the invention.
The heating appliance 100B comprises a frame 101B. The frame 101B has a rear face 102B that is suitable for being secured to a substantially vertical wall. The frame 101B also comprises a casing 103B. The rear face 102B and the casing 103B together demarcate an internal volume 104B of the frame 101B that accommodates a heating element 105B.
The casing 103B comprises a radiating element 106B with a radiating front 107B. According to an embodiment of the invention, the radiating element 106B is covered with a honeycomb plate placed at a distance from the radiating front 107B. The radiating element 106B is heated by the heating element 105B. The heating element 105B is placed so as to heat the radiating element 106B substantially evenly.
According to an embodiment of the invention (not shown), the casing 103B comprises several radiating elements 106B, each with a radiating front 107 and a heating element 105. The radiating elements 106B are arranged so that the radiating fronts 107B of the radiating elements 106 together form a front of the appliance 100B.
The casing 103B comprises a phase-change material 109B.
The material 109B is for example paraffin, alcohol, silica gel, molten salt or salt hydrate. In the example presented in FIG. 7, the phase-change material 109B is more precisely placed in the radiating element 106B.
The phase-change material 109B has a phase-change temperature TφB.
According to a preferred embodiment of the invention, the phase-change temperature TφB is that of a solid/liquid-liquid/solid phase change. In one alternative, the phase-change temperature TφB is that of a liquid/gas-gas/liquid phase change. The behavior of the phase-change material 109B is equivalent to that represented in FIG. 2 described above.
Phase-change materials generally have low thermal conductivity. In other words, phase-change materials do not transfer heat easily. Phase-change materials generally have low thermal capacity in pure phase (solid, liquid or gaseous) but high thermal capacity during phase changes (solid/liquid or liquid/gas). In other words, more energy is necessary to increase the temperature of a phase-change material during a phase change than to increase the temperature of a phase-change material in a pure phase.
In the example presented in FIG. 7, the material 109B is placed inside a sealed container 111B forming the radiating element 106B. The container 111B is for example in metal or plastic.
According to another exemplary embodiment, the container comprises material with a cellular structure. In one alternative, the material 109B is used to soak another porous solid material. The porous solid material is preferably a composite material. The material 109B that soaks the composite material is for example paraffin used to soak ceramic or molten salt encapsulated in polymer balls.
In the example presented in FIG. 7, the heating element 105B is placed against a rear face 108B of the radiating element 106B. The heating element 105B is for example a resistor that has been printed on plastic film or a heating cable. In one alternative, the heating element 105B is embedded in the phase-change material 109B inside the container 111B. In another alternative, the heating element 105B is a resistive wire, and the container 111B comprises a compartment in which is placed the resistive wire embedded in electrically insulating and thermally conductive material 116A, for example magnesia, and one or more other compartments in which the phase-change material 109B is placed. The use of a honeycomb plate covering the radiating element 106B is particularly adapted to that last alternative. This alternative is identical to that presented in FIG. 5 for the second embodiment.
In the example presented in FIG. 7, the phase-change material 109B is selected so that its phase-change temperature TφB is slightly lower than a required temperature TvB of the radiating front 107B. The required temperature TvB is for example substantially equal to the temperature Tf of the radiating front 107A, when the temperature of the room Tp in which the appliance 100B is installed has reached the set temperature Tc. ‘Slightly lower’ means that the difference between the phase-change temperature TφB and the required temperature TvB does not exceed 70° C. The required temperature TvB is for example entered in a data memory of a regulating device (not shown) of the appliance 100B.
In that way, the temperature of the heating appliance 100B increases rapidly and decreases slowly, thus improving the comfort of the user.
FIG. 9 shows the change in the temperature Tf of the radiating front 107B of the appliance 100B over time t, when the temperature of the appliance 100B rises and then falls. FIG. 9 also shows the change in the temperature Tf of the radiating front of an appliance according to the prior art over time t, during the same stages.
At time t11, the appliance 100B and the appliance of the prior art are for example on.
The temperature Tf of the radiating front of the appliance of the prior art increases rapidly till it reaches the required temperature TvB, at which it stabilizes.
When the appliance 100B is on, the phase-change material 109B contained in the radiating element 106B is in the solid state. The temperature Tf of the radiating front 107B of the appliance 100B increases rapidly up to a temperature that is slightly below the phase-change temperature TφB of the material 109B, at time t12. At time t12, the material 109B is changing phases: it comprises both a solid phase and a liquid phase. During the change in phases of the material 109B, the temperature Tf of the radiating front 107B progresses at a slower speed till it reaches a temperature slightly higher than the phase-change temperature TφB of the material 109B at time t13.
The temperature Tf of the radiating front 107B increases at a slower speed when the material 109B is changing phases, because the material 109B has lower thermal capacity in the pure phase and higher thermal capacity during a phase change. At time t13, the material 109B is in the liquid state and the temperature Tf of the radiating front 107B starts rising rapidly once again until it reaches the required temperature TvB, around which it stabilizes.
Thus, by selecting a phase-change temperature TφB of the material 109B that is slightly below the required temperature TvB, the high speed at which the temperature of the radiating front 107B rises is only slightly affected. The comfort of the user is thus provided when the temperature of the appliance 100B rises. At time t21, the appliance 100B and the appliance of the prior art are for example off.
The temperature Tf of the radiating front of the appliance of the prior art decreases rapidly until it reaches the room temperature, at which it stabilizes.
When the appliance 100B is off, the phase-change material 109B contained in the radiating element 106B is still in the liquid state. The temperature Tf of the radiating front 107B of the appliance 100B decreases rapidly to a temperature that is slightly higher than the phase-change temperature TφB of the material 109B, at time t22. At time t22, the material 109B is changing phases. During the change in phases of the material 109B, the temperature Tf of the radiating front 107B decreases more slowly to a temperature that is slightly lower than the phase-change temperature TφB of the material 109B, at time t23. At time t23, the material 109B is in the solid state and the temperature Tf of the radiating front 107B starts dropping rapidly once again until it reaches the room temperature, around which it stabilizes.
Thus, by selecting a phase-change temperature TφB of the material 109B that is slightly lower than the required temperature TvB, the drop in the temperature of the radiating front 107B is slowed down by the phase change of the material 109B, which remains at the phase-change temperature TφB for a certain time. The comfort of the user is thus provided when the temperature of the appliance 100B drops.
FIG. 9 shows the appliance 100B according to an alternative of the embodiment presented in FIG. 7. The alternative illustrated in FIG. 9 is also applicable to the first and second embodiment of the invention.
In the example presented in FIG. 9, the container 111B comprises several compartments 112B filled with phase-change material 109B. The container 111B is preferably in aluminum. The compartments 112B are arranged so as to form at least one channel 113B joining the rear face 108B of the radiating element 106B to the radiating front 107B. In the example, the compartments 112B form several channels 113B. The channels 113B are preferably substantially flat and vertical. The channels 113B make it easier to carry heat from the rear face 108B of the radiating element 106B to the radiating front 107B. In the example presented in FIG. 9, the compartments 112B are also arranged so as to form a channel 114B placed substantially parallel to the radiating front 107B.
In the example presented in FIG. 9, the radiating front 107B is convex. The radiating front 107B is convex from bottom to top. The terms ‘top’ and ‘bottom’ are to be understood when the appliance 100B is secured to a vertical wall. The channels 113B are arranged like spokes from the rear face 108 of the radiating element 106B to the convex radiating front 107B. In an alternative, the radiating front 107B is concave from bottom to top. In another alternative, the radiating front 107B forms one or more waves.
The third embodiment of the invention can advantageously be combined with the first embodiment of the invention. The radiating element 106B then comprises a second phase-change material 109 with a phase-change temperature TφA that is slightly higher than a maximum temperature Tmax permitted for the casing 103B.
Thus, the appliance 110B offers both the benefits relating to the use of the phase-change material 109B and the benefits relating to the use of the second phase-change material 109.
The third embodiment of the invention can advantageously be combined with the second embodiment of the invention. The radiating element 106B then comprises a second phase-change material 109A with a phase-change temperature TφA that is substantially equal to a required temperature TvA of the radiating front 107B. The required temperature TvB of the radiating front 107B may be equal to or different from the required temperature TvA of the radiating front 107B. Thus, the appliance 110B offers both the benefits relating to the use of the phase-change material 109B and the benefits relating to the use of the second phase-change material 109A.
The third embodiment of the invention can advantageously be combined with the first and second embodiment of the invention.
The radiating element 106B then comprises a second phase-change material 109 with a phase-change temperature Tφ that is slightly higher than the maximum temperature Tmax permitted for the casing 103B, and a third phase-change material 109A with phase-change temperature TφA that is substantially equal to a required temperature TvA of the radiating front 107B. The required temperature TvB of the radiating front 107B may be equal to or different from the required temperature TvA of the radiating front 107B. Thus, the appliance 110B offers both the benefits relating to the use of the phase-change material 109B, the benefits relating to the use of the second phase-change material 109, and the benefits relating to the use of the third phase-change material 109A.

Claims

1-10. (canceled)

11. Electrical heating appliance, comprising:

a frame comprising a casing and a rear face demarcating an internal volume of the frame, wherein the rear face is securable to a wall that is substantially vertical;

a heating element placed in the internal volume of the frame; and

wherein the casing comprises a phase-change material.

12. Electrical heating appliance according to claim 11, wherein the casing comprises a radiating element with a radiating front, heated by the heating element; and wherein the phase-change material is placed in the radiating element.

13. Electrical heating appliance according to claim 11, wherein a phase-change temperature of the phase-change material is higher than a maximum temperature permitted for the casing.

14. Electrical heating appliance according to claim 12, wherein a phase-change temperature of the phase-change material is substantially equal to a required temperature of the radiating front.

15. Electrical heating appliance according to claim 13, wherein the radiating element comprises a second phase-change material with a phase-change temperature that is higher than a maximum temperature permitted for the casing.

16. Electrical heating appliance according to claim 12, wherein a phase-change temperature of the phase-change material is lower than a required temperature of the radiating front.

17. Electrical heating appliance according to claim 16, wherein the radiating element comprises a second phase-change material with a phase-change temperature that is higher than a maximum temperature permitted for the casing.

18. Electrical heating appliance according to claim 17, wherein the radiating element comprises a third phase-change material with a phase-change temperature that is substantially equal to a required temperature of the radiating front.

19. Electrical heating appliance according to claim 12, wherein the radiating element forms a sealed container comprising a plurality of compartments, within which the phase-change material is placed; and wherein the compartments are arranged to form at least one channel connecting a rear face of the radiating element with the radiating front.

20. Electrical heating appliance according to claim 19, wherein the compartments are arranged to form at least one channel placed substantially parallel to the radiating front.