Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24D—DOMESTIC- OR SPACE-HEATING SYSTEMS, e.g. CENTRAL HEATING SYSTEMS; DOMESTIC HOT-WATER SUPPLY SYSTEMS; ELEMENTS OR COMPONENTS THEREFOR
  • F24D19/00—Details
  • F24D19/10—Arrangement or mounting of control or safety devices
  • F24D19/1096—Arrangement or mounting of control or safety devices for electric heating systems
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
  • F24H9/00—Details
  • F24H9/20—Arrangement or mounting of control or safety devices
  • F24H9/2064—Arrangement or mounting of control or safety devices for air heaters
  • F24H9/2071—Arrangement or mounting of control or safety devices for air heaters using electrical energy supply
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
  • H05B1/00—Details of electric heating devices
  • H05B1/02—Automatic switching arrangements specially adapted to apparatus ; Control of heating devices
  • H05B1/0227—Applications
  • H05B1/0252—Domestic applications
  • H05B1/0275—Heating of spaces, e.g. rooms, wardrobes
  • H05B1/0277—Electric radiators
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24D—DOMESTIC- OR SPACE-HEATING SYSTEMS, e.g. CENTRAL HEATING SYSTEMS; DOMESTIC HOT-WATER SUPPLY SYSTEMS; ELEMENTS OR COMPONENTS THEREFOR
  • F24D2200/00—Heat sources or energy sources
  • F24D2200/08—Electric heater
• • G—PHYSICS
  • G05—CONTROLLING; REGULATING
  • G05F—SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES
  • G05F1/00—Automatic systems in which deviations of an electric quantity from one or more predetermined values are detected at the output of the system and fed back to a device within the system to restore the detected quantity to its predetermined value or values, i.e. retroactive systems
  • G05F1/66—Regulating electric power

Definitions

• the present invention relates to a heating electric radiator (for heating building interiors) and to a method for controlling a heating electric radiator.
• electric radiators for space heating have a metal body with heat exchange surfaces facing the space to be heated and an electric heating element (i.e. with an electrical supply) which, when supplied with electric power, heats up and in turn heats the heat exchange surfaces and/or a heating fluid circulating in a circuit inside the radiator and transferring heat to the heat exchange surfaces.
• an electric heating element i.e. with an electrical supply
• the heating element is typically a resistive heating element, controlled by a control unit, e.g. an electronic control board, connected to a user interface.
• a control unit e.g. an electronic control board
• the heating elements are normally available with preset thermal values but in different sizes.
• the current market trend is having the same power with the smallest possible encumbrance.
• the regulations in several countries require that radiators have preset maximum surface temperatures and do not cause any excessive overheating with respect to ambient temperature.
• One way to avoid any unacceptable overheating is to provide the radiator with temperature regulation and control systems, e.g. a thermostat, which interrupts the electrical supply of the heating element when the surface temperature of the radiator reaches a preset threshold.
• temperature regulation and control systems e.g. a thermostat
• thermostatic/electronic controls that, by means of thermal sensors, alternatively measure the surface temperature or the air temperature determined by the convective or radiative heat flux of the heat exchange surfaces .
• control is carried out by a sensitive element that is arranged in a specific point of the radiator, thus being difficult to see it as a global maximum temperature;
• the proposed systems read the temperatures of parts of the radiator that have a noticeable thermal inertia: this prevents a precise control of the temperatures and can result in a reduction of the emitted thermal power or thermal energy;
• the temperature control if performed by thermostats, shows a hysteresis of some degrees centigrade; also the electronic regulation normally shows a hysteresis to avoid any "flickering" about the set-point;
• the surface temperature control is not the differential control if compared to the ambient temperature as required by the regulations: the result is thus an intermittent operation of the radiator, whereby in real conditions the radiator is not able to ensure a supply of thermal power or thermal energy corresponding or close to the nominal electric power under all different installation conditions .
• the present invention therefore relates to a heating electric radiator and to a method for controlling a heating electric radiator as defined in the enclosed claims 1 and 6, respectively, as well as, for their preferred additional features, in the dependent claims.
• the control of the radiator temperature differential with respect to the environment is obtained by controlling the power/energy supplied to the resistive heating element.
• the temperature difference i.e. the difference in temperature between the radiator and the surrounding space
• the applied power/energy is a function of the applied power/energy.
• the control unit of the electric radiator of the invention therefore integrates a power controller which limits, in particular by means of an on-off system, the time in which the heating element is on so as to never exceed a preset energy limit corresponding to an operating condition in which the temperature of the heat exchange surfaces is maintained within a preset threshold complying with the overheating regulations.
• the control unit detects the power supplied to the heating element (directly or by detecting power-related electrical quantities and calculating the power based on these electrical quantities) and compares it to a preset threshold value, suitably calculated and verified so as to meet the operating requirements and regulations and to guarantee the maximum thermal power in the long term (thermal energy) .
• the control unit operates to keep the energy supplied to the heating element below the preset energy limit and if a detected power exceeds the threshold value, operates accordingly to interrupt or reduce the electrical supply to the heating element. If the power detected over a certain time interval exceeds the threshold value, the control unit interrupts or reduces the power supply to the heating element.
• the invention permits overcoming the usual power limit related to the radiator size (allowing in particular a size reduction though maintaining the same thermal/electric power) ;
• the invention permits reducing temperature fluctuations during the radiator operation
• the invention ensures that the thermal power supplied by the radiator corresponds to a nominal electric power within the limits complying with the regulations;
• the invention also permits providing the user with indications on actual consumption.
• FIG. 1 is a schematic view of a heating electric radiator according to the invention.
• FIG. 2 is an energy/time graph, which schematically illustrates the operating modes of the radiator of the invention .
• Figure 1 indicates as a whole with 1 an electric radiator for space heating.
• the radiator 1 comprises a body 2, preferably made of a metal material and provided with an inner cavity 3 and outer heat exchange surfaces 4, facing in use the space to be heated; an electric power heating element 5 housed in the cavity 3; an electric power supply connection 6 connectable to an external power network; and a control unit 7 connected to the heating element 5 and to the power supply connection 6 for controlling the electrical supply of the heating element 5.
• the heating element 5 is a substantially known electric power heating element, in particular a resistive heating element, consisting for example of an electrical resistance incorporated or embedded in a block of suitable material (mineral, stone, composite, refractory, metal material, etc . ) .
• the control unit 7 comprises e.g. an electronic control card connected to a user interface 8.
• the control unit 7 includes a power controller 9, configured to detect the power supplied to the heating element 5.
• the control unit 7 is able to directly detect the power supplied to the heating element 5, or is configured to detect power-related electrical quantities and to calculate the power based on the detected electrical quantities.
• Power detection can take place continuously or at preset intervals .
• the control unit 7 has a memory containing a preset power threshold value Pum, which is the power at which no overheating occurs, namely at which the radiator 1 operates according to its design specifications and in compliance with the regulations.
• the threshold value can be given e.g. by the nominal electric power.
• control unit 7 When the control unit 7 detects an electric power supplied to the heating element 5 greater than the preset threshold value Pum, the control unit 7 operates through the controller 9 to limit the energy supplied to the heating element 5.
• control unit 7 operates by means of an on- off system to adjust the time in which the heating element 5 is on (i.e. the time in which the heating element 5 is supplied) so as to never exceed a preset energy limit En m (also stored in the memory of the control unit 7), corresponding to an operating condition in which the temperature of the heat exchange surfaces is maintained within a preset limit complying with the overheating regulations .
• a preset energy limit En m also stored in the memory of the control unit 7
• the control unit 7 detects the power supplied to the heating element 5 (directly or by detecting power-related electrical quantities and calculating the power based on these electrical quantities) and compares it with the preset threshold value Pum, suitably calculated and verified so as to meet the operating requirements and regulations .
• the control unit 7 then operates to keep the energy supplied to the heating element 5 below the corresponding energy limit En m and, if a detected power exceeds the threshold value, operates accordingly to interrupt or reduce the electrical supply to the heating element 5.
• control unit 7 interrupts or reduces the electrical supply to the heating element 5.
• the control unit 7 starts again supplying the heating element 5 after a preset interval, or when the energy reaches a minimum value or falls below the threshold value. In other words, the control unit 7 controls the supply of the heating element 5 so that the energy supplied to the heating element 5 never exceeds the energy limit En m and never falls below a minimum threshold.
• FIG. 1 shows schematically some possible operating conditions of the radiator 1.
• Figure 2 is a graph representing the energy E supplied to the radiator 1 (specifically to the heating element 5) as a function of the time T.
• ERef is the energy supplied in the reference time TRef
• the preset energy limit En m is the energy that, having been supplied to the radiator 1 in the reference time Ref, allows maintaining the preset operating conditions with respect to the overheating of the heat exchange surfaces.
• Line A represents the limit operating condition in which the detected power P (measured by the slope of line A in the energy/time graph) equals the threshold value Pum (in the non-limiting example of Figure 2, corresponding to an energy equal to 95% of the energy limit En m ) .
• Line B represents an operating condition in which the detected power (measured by the slope of line A in the energy/time graph) is lower than the threshold value Piim.
• the control unit 7 detects a power lower than the threshold value P um, the control unit 7 keeps supplying the heating element 5.
• Line C represents an operating condition in which the detected power P is greater than the threshold value P um .
• the control unit 7 detects a power greater than the threshold value P um, the control unit 7 stops supplying the heating element 5 for a preset time period, calculated so that the energy supplied during this period (i.e. power over time) is lower than the energy limit En m .
• the threshold power value Pum therefore serves to establish whether it is necessary to stop supplying the heating element 5.
• the energy limit En m is instead used to define the reduction of the energy supplied to the heating element 5. It is clear that it can also be used a threshold power value Pum corresponding to the same energy limit En m so that the two thresholds coincide, as well as threshold values and energy limits corresponding to different percentages if compared to those given here by way of example.

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• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Central Heating Systems (AREA)
• Air-Conditioning For Vehicles (AREA)

Applications Claiming Priority (2)

Publications (2)

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ID=59811905

Family Applications (1)

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• 2017
  • 2017-05-02 IT IT102017000047140A patent/IT201700047140A1/it unknown
• 2018
  • 2018-05-02 PT PT187282314T patent/PT3619476T/pt unknown
  • 2018-05-02 WO PCT/IB2018/053045 patent/WO2018203254A1/en not_active Ceased
  • 2018-05-02 EP EP18728231.4A patent/EP3619476B1/de active Active

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