WO2016009449A2

WO2016009449A2 - Led as a heat source

Info

Publication number: WO2016009449A2
Application number: PCT/IN2015/000284
Authority: WO
Inventors: S. Safnil; Thulaseedharan ATHULYA
Original assignee: Individual
Current assignee: Individual
Priority date: 2014-07-16
Filing date: 2015-07-16
Publication date: 2016-01-21
Anticipated expiration: 2017-01-16
Also published as: WO2016009449A3

Abstract

The present invention relates to a system of obtaining heat from at least one illumination device for heating purposes. In one embodiment, the system comprising: a power supply to power the current driver, wherein the power supply includes AC or DC supply or both, a current driver coupled to at least one illumination device to supply DC power, wherein the current driver converts its input to suitable DC supply, at least one illumination device with at least one light emitting module which receives DC supply from the current driver to illuminate with heat energy, and a base plate (heat sink) positioned in the underneath region of the at least one illumination device, wherein the base plate is to receive the heat energy from at least one illumination device while illumining and spreads it uniformly, enhancing non radiative auger recombination heat output can be improved and light output can be reduced which make LED a better heat source

Description

Title

LED AS A HEAT SOURCE

Field of the invention

The present invention mainly relates to heat source and more particularly use of Light Emitting Diode (LED) as heat source.

Background of the invention Heat source is well known in the art for hearing purposes, for example which may be used for heatinghouse hold appliances. Current technology used for heating purposes is commonly coil based, etcwhich utilize joule loss. For a resistor placed across a power line supplied with electricity having AC current. Rl² [resistor * (current*current)] is equal to heat in watts. This is the major principle behind coil based heat devices. Different kind of heating elements are used in different appliances like iron, toaster, hair dryer, etc. Basically these heating element convert electricity into heat through the process of resistive or joule heating.

For an electric iron it contain a resistive wire (nichrome) when a current of I amp is passed through the wire, electrical energy equal to Rl²1 in joules is produced which is entirely convert to heat. This is the unique char of resistive element as compared to capacitors or inductor where there is no power dissipation. Here R = resistance of the wire in Ohm, t = amount of time that the current passes though the resistance wire. ,

The metal base at the bottom of the electric iron is thus heated up. In order to cut-off current passing through the coil when allowable temperature is reached thermostat is used in series with the coil. Heating is commonly done to temp of 180- 200 degree Celsius. Generally used heating elements are Nichrome, resistor wire like kanthal (FeCrAI) wire, Nichrome wire and strip, cupronickel (CuNi) etc.

Currently using heating mechanism, consumes more powerfor example the conventional iron box consumes 1000watt power which outputs only 120 degree to 200 degree Celsius.

Further, a light-emitting diode (LED) is well known in the art which is a two- leadsemiconductor light source. It is a basic pn-junction diode, which emits light when activated. The light emitting diode may be driven to emit light by the supply of forward voltage so that the electrons are able to recombine with electron holes within the device, releasing energy in the form of photons. This effect is calledelectroluminescence, and the colour of the light (corresponding to the energy of the photon) is determined by the energy band gap of the semiconductor.

The LED is often small in area (less than 1 mm²), and integrated optical components may be used to shape its radiation pattern. Early LEDs were often used as indicator lamps for electronic devices, replacing small incandescent bulbs. Recent developments in LEDs permit them to be used in environmental and task lighting. LEDs have many advantages over incandescent light sources including lower energy consumption, longer lifetime, improved physical robustness, smaller size, and faster switching.

Light-emitting diodes are now used in applications as diverse as aviation lighting, automotive headlamps, advertising, general lighting, traffic signals, camera flashes, etc. However, LEDs powerful enough for room lighting are still relatively expensive, and require more precise current and heat management than compact fluorescent lamp sources of comparable output. Due to use in various applications, theLED lights has heat problem which seriously affects the design and promotion of LED lights. To solve this, the heat from the LED lights are transferred to the open environment.And another technique is use of cooling device for cooling the LED, and there are different types of cooling technique to cool the LED. Here the heat resources from the LED are getting wasted to the open environment or to any cooling devices.

Therefore there is a need in the art with a solution to utilize LED heat source and also reduce the power consumption in heating purposes.

Objective of the invention

The main objective of the present invention is to utilize the LED heat source for heating purposes like iron box, bread toaster, water heater etc.

Another objective of the present invention is to reduce the power consumption for heating purposes like iron box, bread toaster, water heater etc by using LED as a heat source which is nearly 1/10 times less as compared with current coil based technology.

Summary of the Invention

An aspect of the present invention is to address at least the above-mentioned problems and/or disadvantages and to provide at least the advantages described below.

Accordingly, in one aspect of the present invention relates to a system of obtaining heat from at least one illumination device for heating purposes, the system comprising: a power supply to power the current driver, wherein the power supply includes AC or DC supply or both, a current driver coupled to at least one illumination device to supply DC power, wherein the current driver converts input supply to suitable DC supply, at least one illumination device with at least one light emitting module which receives DC supply from the current driver to illuminate with heat energy, and a base plate positioned in the underneath region of the at least one illumination device, wherein the base plate is to receive the heat energy from at least one illumination device while illumining and spreads it uniformly.

Other aspects, advantages, and salient features of the invention will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses exemplary embodiments of the invention.

Brief description of the drawings The above and other aspects, features, and advantages of certain exemplary embodiments of the present invention will be more apparent from the following description taken in conjunction with the accompanying drawings in which:

Figure 1 shows the system of LED as a heat source according to one embodiment of the present invention.

Figure 2 shows the working example of LED as a heat source coupled to small house hold appliances according to one embodiment of the present invention.

Persons skilled in the art will appreciate that elements in the figures are illustrated for simplicity and clarity and may have not been drawn to scale. For example, the dimensions of some of the elements in the figure may be exaggerated relative to other elements to help to improve understanding of various exemplary embodiments of the present disclosure.

Throughout the drawings, it should be noted that like reference numbers are used to depict the same or similar elements, features, and structures. Detailed description of the invention

The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of exemplary embodiments of the invention as defined by the claims and their equivalents. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope and spirit of the invention. In addition, descriptions of well-known functions and constructions are omitted for clarity and conciseness.

The terms and words used in the following description and claims are not limited to the bibliographical meanings, but, are merely used by the inventor to enable a clear and consistent understanding of the invention. Accordingly, it should be apparent to those skilled in the art that the following description of exemplary embodiments of the present invention are provided for illustration purpose only and not for the purpose of limiting the invention as defined by the appended claims and their equivalents.

It is to be understood that the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to "a component surface" includes reference to one or more of such surfaces.

By the term "substantially" it is meant that the recited characteristic, parameter, or value need not be achieved exactly, but that deviations or variations, including for example, tolerances, measurement error, measurement accuracy limitations and other factors known to those of skill in the art, may occur in amounts that do not preclude the effect the characteristic was intended to provide.

Figs. 1 through2discussed below, and the various embodiments used to describe the principles of the present disclosure in this patent document are by way of illustration only and should not be construed in any way that would limit the scope of the disclosure. Those skilled in the art will understand that the principles of the present disclosure may be implemented in any suitably arranged communications system. The terms used to describe various embodiments are exemplary. It should be understood that these are provided to merely aid the understanding of the description, and that their use and definitions in no way limit the scope of the invention. Terms first, second, and the like are used to differentiate between objects having the same terminology and are in no way intended to represent a chronological order, unless where explicitly stated otherwise. A set is defined as a non-empty set including at least one element. The present invention uses the Light Emitting Diode (LED) as a heat source so that the user can utilize the heat source with power consumption nearly 1/10 times less than as compared with that of coil giving same heat output.. Since Light Emitting Diode (LED) can be driven by a battery, LED based heating appliances provide more flexibility to user. Figure 1 shows the systemof LED as a heat source according to one embodiment of the present invention. The figure shows the system of LED as a heater source. The system consists of power supply, current driver, illumination device (LED array), base plate, etc.

LED AS A HEAT SOURCE: Light Emitting Diode (LED) consists of a P-type semiconductor in contact with an N-type semiconductor, this combination of two type of semiconductor is known as P-N junction or a diode. When a PN junction is connected to an external power source, electron from the power source flow to the diode and change the arrangement of electrons in the diode.

When a LED forward biased the electrons from the voltage source flow into N- type side of the PN junction and occupy the conduction band, since there is no space in the valance band of the N-type semiconductor. As the electron comes into conduction band, they will be pushed to the P-type side of the PN junction which has more space to hold electrons. The electrons go into the empty conduction band of the P-type side, since they already occupy the higher energy band in the N-type side. In order to occupy stability electrons from higher energy band of P-type side will jump to the valance band or low energy band. As the electrons cross the band gap energy related in magnitude to the size of the band gap is released in the form of light. This type of recombination is called radiative recombination.

In addition to radiative recombination in LED non radiative recombination will occur, when recombination of hole and electrons occur rather than emitting the energy as light or as photon the energy is given to a third carrier, an electron in the conduction band. This electron then thermalizes back down to the conduction band or conduction band edge such kind of recombination is called non radiative or auger combination and it is most important at high carrier concentration this results in around 75% heat as output.

AUGER EFFECT: This is physical phenomenon in which the filling of inner shell vacancies of an atom is accompanied by the emission of electron from a same atom. When a core electron is removed leaving a vacancy, an electron from a higher energy level will fall in to vacancies, resulting in a release of energy although most of the time this energy is released in the form of emitted photon, the energy can also be transferred to another electron, which is injected from the atom. This second injected electron is called auger electron.

Upon ejection the kinetic energy of the auger electron correspond to the difference between the energy of the initial electronic transition into vacancies and the ionisation energy for the electron shell from which the auger electron are injected. The energy level depends upon type of atom and chemical environment where the atom is located.Auger recombination is a similar auger effect which occurs in semiconductor. An electron and electron hole can recombine and gives up their energy to an electron in the conduction band increasing its energy. For LED photon emitted as larger energy than the band gap, therefore we lose the extra energy by thermilization. The carrier loose energy due to collision with lattices give away their kinetic energy and results in phonon generation. In addition, as the operating temperature of the LED rises it promotes electron to higher energy state in the conduction band, which as the effect of giving nominally direct band gap semiconductor some indirect band gap character. This can occur since electron can be thermally promoted to occupy second valley in the conduction band of direct band gap semiconductors. These electrons are then forced to recombine indirectly and hence heat output will continue. Smaller the energy barrier between primary and secondary valley then easier it becomes in thermally excite electron between them. Auger recombination can also occur by the effect of polarisation field, quantum confinement, lattice scattering etc. which causes shifting of wave function of electrons in conduction band which reduces spontaneous or radiative recombination and causes momentum conserving direct transition to higher energy states which then results high heat output. This auger recombination is a mechanism of non- recombination this result in around 70-80% of heat output in LED.

Utilization of heat can bring a temperature done and effective transferring of heat from junction to a plane heat sink can give hot plate from which heat can be utilized.

In the present invention the system of LED as a heat source consists of power supply, current driver, illumination device (LED array), base plate (heat sink), etc. The power supply is to power the current driver, where the power supply includes AC and DC supply. Input power converts it to suitable range of dc supply. The DC supply from the current driver connected to at least one illumination device. The system includes one or more illumination device with one or more light emitting module which receives DC supply from the current driver to illuminate with heat energy. The base plate (heat sink) positioned in the underneath region of the at least one illumination device, wherein the base plate is to receive the heat energy from at least one illumination device while illumining and spreads it uniformly through base plate. The heat energy from the one or more illumination devices are utilized for heating purposes but not limited to iron box, bread toaster, water heater, etc. The illumining level and hence the junction temperature of at least one illumination device is controllable and it is achieved by adjusting DC current from the current driver. The light emitting module may be an LED array, other type of lights, etc. where the LED array has at least one substrate, and at least one LED bulb. In the present invention the LED arrays of different internal resistance is to achieve wide variation of temperature and gives cut-off to the LED once required temperature is reached.

In the present invention system the LED array is supplied with suitable DC supply using current driver and LED array attached with base metal (heat sink) of the iron box using a thermal conducting dielectric. These sense 120° C - 150° C on the base metal using a thermister.

Figure 2 shows the working example of LED as a heat source coupled to heating appliances according to one embodiment of the present invention. The figure shows the working example of LED as a heat source coupled to various heating appliances. As an example

Developing Led Iron Box:

The figure shows an example of developing a led iron Box. The led iron box consists of power supply, current driver, illumination device (led array), and heat conducting plate or base plate (heat conducting plate acts as heat sink). The high power LED array linked to a heat conducting plate using thermal conductive dielectric. The suitable supply to LED array forms an LED iron box. The thermal conductive dielectric ensures thermal conduction without electric conduction to the plate. For a particular LED array it should be provided with a particular range of current. Hence present invention uses a suitable current driver. Input supply to DC of suitable current or DC from battery can be directly used, which is then supplied to LED array. When LED turns ON the heat is produced. The LED array is mould on to base plate using thermal dielectric and the led array transfers the heat to the base plate. When desired temperature is reached on the metal plate (heat conducting plate or base plate) it can be sensed and cut off can be provided to the supply of the current driver. For ironing different clothes, different temperature is needed. Such temperature control may be obtained by varying the current applied to LED within a safe limit. Advanced heat control is possible by using different LED arrays having different internal impedance (which mean varying internal resistance). In the present invention the DC may be given directly from battery Developing Led Water Heater:

Another example is, LED water Heater. The led water heater consists of power supply, current driver, illumination device (LED array), base plate, the LED array with base plate is mounted on a cold plate with a water cooling circuit is developed to LED heater, so that water which circulate through cold plate can be heated or boiled. Base plate of LED is connecting with a cold plate causes convective heat transfer between base plate and liquid circulated through cold plate. This hot water formed can be utilised and cold water can be again pumped to cold plate using a mini pump. Cold plate is the one which is used to circulate water for heating and named so because it cools LED array.

CONTROLLING OF HEAT:

Controlling of junction temperature can be done by adjusting factors like current, ambient temperature, etc. The heat output can be increased during manufacturing by increasing internal resistance, increase in internal resistance increases heat output. Increasing effect of polarisation field, quantum confinement etc. helps to reduce radiative recombination and enhance non radiative auger recombination i.e. giving high heat output with low light output. Controlling is possible by adjusting current from the current driver. LED arrays of different internal resistance can be used to achieve wide variation of temperature and can give cut-off to the LED when needed temperature is reached.

Applications of the invention:

The present invention technology is utilized for heating purposes. Iron box, bread toaster, water heater etc. can be developed using this technology.

The present invention "LED as a heat source" is utilized for heating purposes like iron box, bread toaster, water heater etc. which is driven by the same power consumed by LED which is nearly 1/10 times less than as compared with that of current coil based technology giving same heat output. The present invention LED array can be driven by battery, etc. may provide more flexibility to user. Advantages of the invention:

The present invention "LED as a heat source" reduces and easily manages the future demand of electricity.

The present invention "LED as a heat source" reduces power consumption for heating purposes.

The present invention "LED as a heat source" works with different watt based on LED power capacity.

The present invention reveals a great research scope for Led technology to use LED as multipurpose efficient source of both heat and light, which makes LED more flexible to use.

Such heat utilization as advantages than conventional heating method both in power consumption and life. LED appliances so designed can work with same power consumed by LED that is 50 or 100 watts instead of 1000 or 1200 watts consumed by coil. FIGS. 1-2are merely representational and are not drawn to scale. Certain portions thereof may be exaggerated, while others may be minimized. FIGS. 1- 2illustrate various embodiments of the invention that can be understood and appropriately carried out by those of ordinary skill in the art.

In the foregoing detailed description of embodiments of the invention, various features are grouped together in a single embodiment for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed embodiments of the invention require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter lies in less than all features of a single disclosed embodiment. Thus, the following claims are hereby incorporated into the detailed description of embodiments of the invention, with each claim standing on its own as a separate embodiment.

It is understood that the above description is intended to be illustrative, and not restrictive. It is intended to cover all alternatives, modifications and equivalents as may be included within the spirit and scope of the invention as defined in the appended claims. Many other embodiments will be apparent to those of skill in the art upon reviewing the above description. The scope of the invention should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. In the appended claims, the terms "including" and "in which" are used as the plain-English equivalents of the respective terms "comprising" and "wherein," respectively.

Claims

CLAIMS:

1. A system of obtaining heat from at least one illumination device for heating purposes, the system comprising: a power supply to power the current driver, wherein the power supply includes AC or DC supply or both; a current driver coupled to at least one illumination device to supply DC power, wherein the current driver converts its input to suitable DC supply; at least one illumination device with at least one light emitting module which receives DC supply from the current driver to illuminate with heat energy; and a base plate positioned in the underneath region of the at least one illumination device, wherein the base plate is to receive the heat energy from at least one illumination device while illumining and spreads it uniformly.

2. The system as claimed in claim 1 , wherein the power supply to current driver is supplied by battery, generator, etc.

3. The system as claimed in claim 1 , wherein the light emitting module is a LED array, the LED array has at least one substrate, and at least one LED bulb.

4. The system as claimed in claim 3, wherein the LED arrays of different internal resistance is used to achieve wide variation of temperature.

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5. The system as claimed in claim 1 , wherein the power supply to at least one illumination device is cut-off when the base plate reaches the required/predefined temperature.

6. The system as claimed in claim 1 , wherein heat removal from LED by utilization can make it a heat source.

7. The system as claimed in claim 1 , wherein the heat energy from at least one illumination device is utilized for heating purposes like iron box, bread toaster, water heater, etc.