PORTABLE HEATING SYSTEM

Abstract

The invention relates to a portable heating system that in a first instance provides heat and in a second instance provides a source of electrical current from thermo electric modules where the produced electrical energy is intended to be forwarded to a rechargeable battery. The rechargeable battery serves as a current source for the portable heating system e.g. for driving the fuel pump and air fans. When the rechargeable battery is replenished with electrical energy a control is configured to switch the by the thermo electrical modules generated electrical energy to selected power consumers arranged with the portable heating system in order to facilitate the thermo electrical modules to keep the intended quality serving as a heat pump for transferring the produced heat from a burner to a transportation media for releasing the heat in the designated intended area.

Claims

1. A portable heating system (PHS), comprising: an air inlet; a combustion chamber for combustion of fuel; a burner connected to the air inlet, the burner comprising a fuel inlet for introducing fuel to the burner; a combustion blower for blowing air from the air inlet into the combustion chamber thereby allowing for production of heat by combustion of the fuel; an outlet for releasing exhaust from the combustion chamber; a heat exchanger, interfacing the combustion chamber and exchanging heat with a heat transporting media, the heat exchanger comprising: a first side, arranged in such a way as to absorb heat from the combustion chamber; a second side for releasing heat into the heat transporting media; at least one thermoelectric module arranged between the first side and second side of the heat exchanger for producing electrical power; a rechargeable battery for absorbing the electrical power generated by the at least one thermoelectrical module; a control that monitors the electrical power generated by the at least one thermoelectric module and regulates a current draw from the at least one thermoelectric module to a level within a preset range of current draw corresponding to a preset range of thermal conductivity of the at least one thermoelectrical module by distribution of the generated electrical power into selected electrical power consumers arranged with the PHS.

2. The PHS according to claim 1, wherein the control is adapted as to monitor the charging of a battery to be supplied with electrical power from the at least one thermoelectric module and to switch off the charging when a threshold voltage level on the battery defining a state of full charge has been reached and subsequently connect the thermoelectric module with one or more of the electrical power consumers that consume at least an amount of electrical power that provides increased thermal conductivity of the at least one thermoelectrical module.

3. The PHS according to claim 1, wherein the control is adapted as to monitor the charging of a battery connected to be supplied with electrical power from the at least one thermoelectric module and to provide a pulse width modulated (PWM) signal for distribution of electrical power generated by the at least one thermoelectric module and provide electrical power to the battery during a first period of the PWM signal and to provide electrical power to an electrical power consumer during a second period of the PWM signal and where a PWM ratio of the PWM signal is adjusted in response to the monitored charging level of the battery to absorb in total at least an amount of electrical power that provides an increased thermal conductivity of the at least one thermoelectrical module.

4. The PHS according to claim 3, wherein a pulse-pause length of the PWM signal is configured to be in a range of 1 microsecond to 10 minutes.

5. The PHS according to claim 4, wherein the control includes a switching device to be controlled by the PWM signal for at least one of recharging a battery or supplying a consumer where the switching device is a relay.

6. The PHS according to claim 4, wherein the control includes a switching device to be controlled by the PWM signal for at least one of recharging a battery or supplying a consumer where the switching device is one of a bipolar transistor, Field Effect Transistor or a Metal Oxide Semiconductor Field Effect Transistor (MOSFET).

7. The PHS according to claim 6, wherein the pulse-pause length is configured to be between 1 millisecond to 1000 milliseconds.

8. The PHS according to claim 1, wherein a thermo sensor is arranged with the rechargeable battery to determine a temperature of the battery and give input to the control.

9. The PHS according claim 1, wherein the control is configured to determine a value of the PWM signal to provide a charging current to the rechargeable battery based on a temperature of the battery and corresponding preconfigured safe charge values mapped to the temperature of the battery, the safe charge values being stored with the control.

10. The PHS according claim 1, wherein the electrical consumer is one or more resistive heating elements for dissipation of electrical power and converting the electrical power into heat.

11. The PHS according to claim 10, wherein the resistive heating element is arranged within the PHS for heating one of the following: air inlet; a fuel tank; a fuel pump; a fuel inlet to the fuel pump; a motor for a combustion blower; a circulation pump if a transportation media of heat is liquid based; a buffer water tank for heated water if the transportation media of heat is liquid base; a motor for an air-blower if the transportation media of heat is air based; rechargeable battery.

12. The PHS according claim 1, wherein the control is adapted to monitor the temperature of the rechargeable battery and in case the temperature of the rechargeable battery exceeds a predetermined value disconnect a heating element arranged with the battery to avoid excess heating of the rechargeable battery.

13. The PHS claim 1, wherein the electrical consumer is a clamp that short circuits the at least one thermoelectric module and dissipates the electrical power generated by the at least one thermoelectric module in an inner resistance of the thermoelectric module.

14. The PHS claim 1, wherein the control is configured to provide a motor for 1) an electric fuel pump, 2) a combustion air-blower, 3) an air-blower, 4) a circulation pump with a supply current that varies in amplitude and polarization so as to regulate the motor to inefficiency but keeping an intended velocity so as to burn electric power generated by the at least one thermoelectric module in the motor and provide heat.

15. The PHS according to claim 14 wherein the motor is one of a DC motor with brushes, a brushless DC motor or a Stepper motor.

16. The PHS according to claim 1, further comprising a temperature sensor on a hot side of the at least one thermoelectrical module where the control is adapted to monitor the temperature on the hot side of the at least one thermoelectrical module and in case the temperature level exceeds a temperature threshold value, the control increases a current draw from the at least one thermoelectrical module until the temperature level on the hot side is beyond the temperature threshold value and in case a maximum threshold value for the current draw is reached and the temperature level still exceeds the temperature threshold value, the control further controls a fuel pump in order to decrease an amount of fluid supplied to the burner until a state is reached where the temperature level on the hot side of the at least one thermoelectrical module is not exceeding the temperature threshold value.

17-18. (canceled)

19. The PHS according to claim 16, wherein the control is configured to, in case the temperature on the hot side of the at least one thermoelectrical module is below a second threshold temperature and there is still a demand for producing heat, the control reacts by increasing the supply of fuel to the burner and thus producing more heat.

20. The PHS according claim 16, wherein the control is configured to, in case the temperature on the hot side of the at least one thermoelectrical module is below a second threshold temperature and there is still a demand for producing heat, the control is configured to lower the current draw to match a threshold level for current draw that increases efficiency of the system.

21-24. (canceled)

25. The PHS according to claim 1, wherein the control is adapted to regulate a fuel pump, a combustion blower and a heat transporting media pump to provide an efficient link for transferring heat from the combustion of fuel to the heat transporting media by utilization of the thermoelectrical elements.

26. The PHS according to claim 1, wherein the thermoelectric modules may be any of thermoelectric p- and n-type semiconductor legs, slices, elements or discs of any shape, or modules with integrated p- and n-type semiconductor legs.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0036] The PHS according to the invention will now be described in more detail with regard to the accompanying figures.

[0037] The figures show one way of implementing the present invention and is not to be construed as being limiting to other possible embodiments falling within the scope of the attached claim set.

[0038] FIG. 1, is a schematic drawing of a PAHS according to some embodiments of the invention,

[0039] FIG. 2, is a top view of a PAHS according to some embodiments of the invention,

[0040] FIG. 3, is a schematic drawing showing a PAHS 1 according to some embodiments of the invention with focus on the electrical features and

[0041] FIG. 4, is a schematic drawing showing various scenarios for distribution of the by the TEG produced electrical energy controlled by the controller, for which the individual embodiments are shown in FIG. 4a-FIG. 4d.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

[0042] For the sake of easy explanation of the inventive concept, a portable heating system (PHS) of the type using air as the heat transportation media is hereby demonstrated. For mobile applications a portable air heating system (PAHS) is practical. However, for the use in caravans, cottages and for many other applications a liquid-based system is preferred. Thus, it is appreciated if all types of PHS is recognized to fall within the scope of the invention.

[0043] FIG. 1 is a schematic drawing of a PAHS according to some embodiments of the invention. The PAHS 1 comprises one or more cabin air inlet 2, one or more combustion air inlet 3, a burner 4 connected to the combustion air inlet 3 via an air inlet chamber 5; a first heat exchanger 6 for producing electricity; a second heat exchanger 7 for increasing the temperature of the air entering the PAHS 1; one of more air outlet 8 to diffuse warm air in the vicinity of the PAHS 1; an exhaust outlet 9 to allow the release of the exhaust from the burner to the outside environment or towards a third heat exchanger.

[0044] When in operation fuel is pumped towards the burner 4 though piping (not shown) and air is allowed to enter the PAHS via air inlet 2. Part of this air is directed towards the burner 4 via a burner air blower 11 (not shown in FIG. 1 but shown in FIG. 2). Most of the air entering the air inlet 2 is blown towards the first heat exchanger 6 by a main air fan 10. The main air fan 10 and the burner air blower 11 may be mechanically independent as well as independently powered. This configuration has the great advantage that the air flux can be optimized depending on the need of the PAHS. For example, at start the main air fan 10 does not need to blow air to be heated by the first and second heat exchanger as these exchangers are not hot as the burner has not started yet or have been just started. The burner air blower 11 on the contrary needs to blow air inside the burner so as to start the burner and produce heat. Thus, the speed and the need of the main air fan 10 and the burner air blower are quite different, and the detachment of their operability optimizes their function and reduces the electricity and fuel consumption. For example, when the heat exchangers 6,7 are hot, the burner 4 can be stopped, i.e. the burner air blower 11 can also stop, while the main air fan 10 needs to blow continuously so as to take advantage of the hot heat exchangers and thus producing hot air that is released via hot air outlet 8. The fuel used may be in the liquid, gas or solid form.

[0045] FIG. 2 is a top view of a PAHS 1 according to some embodiments of the invention. FIG. 2 shows PAHS 1 comprising a cabin air inlet 2 allowing air to enter an air intake chamber 12. When in operation, the air in the air intake chamber 12 is blown via the main air fan 10 inside the PAHS 1 from the air intake chamber 12 towards the first heat exchanger 6 and towards the second heat exchanger 7 so as to produce hot air to be released into the vicinity of the PAHS 1 via air outlet duct 8. From the combustion air inlet 3 air is forwarded via the air inlet chamber 5 to the burner 4 via the burner air blower 11

[0046] A flue pump (not shown) ensures that fuel from a fuel tank is pumped into the burner 4 via internal piping. Heated air and exhaust from the burner exchange heat with the first heat exchanger 6 and the second heat exchanger 7 and leaves the PAHS 1 via exhaust outlet 9.

[0047] Programmed control electronics may control the burner under operation.

[0048] The burner is controlled by a flame sensor (not shown), fuel pump/metering pump (not shown), a temperature sensor (not shown) and the combustion air blower 11.

[0049] In operation by liquid fuel the burner 4 is firstly started: the electric glow wire mesh receives electrical power and start to glow. The fuel is injected onto the glowing wire mesh and also dropped partly onto the glass wool. The burner air blower 11 begins to add the necessary volume of air for combustion. The fuel over the glow wire mesh and dropped on glass wool ignites. The flame sensor senses the glowing from the flame and switch off the electric power to the glowing wire mesh. The flame from dropped fuel on glass wool superheats and evaporates the fuel in the fuel evaporator. Evaporated hot gas injects in the start flame and burns in the present of air, so that the burner4 will run continuously.

[0050] In operation by LPG gas fuel the burner the burner 4 is firstly started: the spark plug receives high voltage electrical power from the electronic ignition system and start to ignite. The LPG fuel will be mixed with air in the primary gas-air mixer 135. The burner air blower 11 begins to add the necessary volume of air for combustion and the burner 4 will run continuously. The flame sensor works as mentioned before.

[0051] The burner is designed so that most of the hot gases will be burned at the flame outlet, which means that most of the hot gases will be burned in the first heat exchanger, i.e. the power generator. An electronic control system (not shown) adjusts the volume of the combustion air and the metering of the fuel in any condition.

[0052] Programmed control electronics may control the burner 4 under operation.

[0053] By operation with liquid fuel the burner 4 is controlled by the flame sensor, fuel pump/metering pump, temperature sensors and the combustion air blower 11.

[0054] By operation with LPG gas fuel the burner is controlled by the flame sensor, Fuel solenoid valve, self-acting thermostatic safety valve and overheat sensor.

[0055] FIG. 3 is a schematic drawing showing a PAHS 1 according to some embodiments of the invention with focus on the electrical features. More expediently, the first heat exchanger 6 for producing electricity features at least one thermoelectric module (TEG) 13 for producing an electric current. From the electric power outlet 14 the electric current produced is led to the controller 15 which monitors the electrical effect generated by the at least one TEG 13 and regulates the current draw from the at least one TEG 13 to a level within a preset range of current draw corresponding to a preset range of thermal conductivity of the at least one TEG 13 by distribution of the generated electrical effect into selected electrical power consumers arranged with the PAHS 1. The controller 15 monitors the battery 16 and do a recharge when needed to keep the battery 16 fully charged. When the electrical current supplied to the battery 16 decreases as the state of full charge is achieved the controller 15 distributes the surplus generated electrical energy to electrical power burners or consumers 17 arranged with the PAHS. Arranged with the PAHS does not necessarily mean fully integrated with the PAHS but also that the power consumer 17 can be arranged external to the PAHS housing. As an example, the battery 16 itself can be arranged inside or outside the PAHS housing free of choice and so as well will it be the case for other electrical power consumers 17. The reason for the controller 15 to distribute the generated electrical power and put a load on the TEG 13 is as earlier described to enable the TEG 13 to act as a thermo pump for transferring heat generated by the burner 4 through the heat exchanger 6 in order to heat the air stream from the cabin air inlet 2 forced through the PAHS with means of the main air fan 10 producing hot air that is released via hot air outlet 8. For the sake of completion, the battery can be any suitable type of battery that satisfies the specifications. The battery type should be chosen carefully with regard to the environment when it comes to performance under low temperature conditions where the battery should still be in a condition as to supply sufficient electrical energy as to start up the PAHS.

[0056] FIG. 4 is a schematic drawing showing four different scenarios a-d for distribution of the by the TEG produced electrical energy controlled by the controller.

[0057] In the first embodiment showed in FIG. 4a, the controller 15 has closed the switch 18 in order to forward the total produced amount of electrical energy from the TEG 13 for recharging the battery 16.

[0058] The second embodiment showed in FIG. 4b, shows the condition where the battery 16 is fully charged and where charging is stopped by the controller 15 by opening the switch 18. This open loop influences the PAHS heavily since the TEG 13 will not be able to work as a thermo pump using the Seebeck effect since the flow of electrons has been stopped. Thus, the thermal conductivity of the semiconductor of the TEG 13 will be lowered and provide a lower transfer ratio of heat from the burner to the heat exchanger fins. This situation should be avoided since overheating in the burner section will be subject to the TEG 13 being damaged.

[0059] In the third embodiment showed in FIG. 4c, the controller 15 upon completion of charging the battery 16 the switch 18 has a third position where in the closed position it connects a power consumer 17. The power consumer is designed to take up sufficient electrical power as to enable the TEG 13 to work as a thermo pump. Referring to FIG. 2 a power consumer 17 in form of a power resistor is arranged in the PAHS. Thus, the surplus electrical power generated is converted into heat which is within the spirit of the invention having the aim of producing heated air. The physical arrangement of the power consumer, here a power resistor, can as shown in FIG. 2 be for heating the combustion air or the cabin air. However, power resistors can be arranged various places as e.g. for heating or evaporating the fuel, for heating the motor or fan environment, for heating the battery and will still be within the scope of the invention.

[0060] In the fourth embodiment showed in FIG. 4d, the switch 18 has by the controller been put in a position to short circuit the TEG 13. Thus, the Seebeck effect is maintained and the heat produced by the TEG is dissipated in the inner resistance of the TEG itself and forwarded to the airstream.