HIGH EFFICIENCY HEATING SYSTEM FOR ELECTRIC VEHICLE

Abstract

A highly efficient heating system for an electric motor vehicle embodies a heat exchanger for warming passenger compartment air and an electrically powered radiant heating source for heating fluid to be circulated through the heat exchanger. The radiant heating source can be infrared, microwave or other frequency selected to efficiently heat the fluid to be circulated through the heat exchanger.

Claims

1. A heating system comprising, a heater assembly including a central axially extending fluid flow passage into which infrared heat is radially directed by an axially coextending infrared heating means, an infrared absorptive fluid supply, and, a pumping means for directing said absorptive fluid through the central flow passage.

2. A heating system as described in claim 1, in which the central flow passage is formed by an outer tube provided on its outer surface with an electrically conductive layer which, when energized, directs infrared radiation radially inwardly to the flow passage.

3. A heating system as described in claim 2, in which the central flow passage is provided by an outer tube and the heating means is provided by a coaxial inner infrared tube heater forming a central passage of annular cross section within said outer tube through which heat is radially outwardly directed.

4. A heating system as described in claim 3, in which the inner surface of said outer tube is provided with a reflective layer.

5. A heating system as described in claim 1, further comprising a fluid to air heat exchanger through which heated fluid is pumped.

6. A heating system according to claim 5, further comprising a fan to force air through said heat exchanger.

7. A heating system for the interior of an electric vehicle comprising a carrier fluid, a fluid distribution structure comprising a heat absorption section and a heat radiation section, a radiant energy source located proximate said heat absorption section and an air distribution system in thermal communication with said heat radiation section.

8. A heating system as claimed in claim 7 wherein said source of radiant energy produces at least one of microwave or infrared energy.

9. A heating system as claimed in claim 7 wherein said source of radiant energy produces microwave energy,

10. A heating system comprising, a heater assembly including a central axially extending outer tube and a coaxial, inner infrared tube heater within said outer tube forming a central passage of annular cross section through which heat is radially outwardly directed from said heater. an infrared absorptive fluid supply, and, a pumping means for directing said absorptive fluid through the central flow passage.

11. A heater assembly according to claim 10 in which said outer tube includes an inner reflective layer facing said heater.

12. A heater assembly according to claim 10 in which said outer tube contains a close fitting inner reflective layer that is separately inserted therein.

13. A heating system according to claim 10, in which said heater assembly is a quartz tube heater producing infrared heat.

14. A heating assembly according to claim 10 in which said heater assembly is a source of microwave energy.

15. A heating system comprising, a heater assembly including a central axially extending fluid flow passage formed within an outer tube provided on its outer surface with an electrically conductive layer which, when energized, directs infrared radiation radially inwardly into which infrared heat is radially directed inwardly.

16. A heater assembly according to claim 15, further comprising, an infrared absorptive fluid supply, and, a pumping means for directing said absorptive fluid through the central flow passage.

17. A heater assembly according to claim 16, further comprising a suspension of heat absorptive granules in said fluid supply.

18. A heater assembly according to claim 17, further comprising, a fluid to air heat exchanger through which heated fluid is pumped, and, a fan to force air through said heat exchanger.

Description

DESCRIPTION OF THE DRAWING

[0022] FIG. 1 illustrates four components useful in the implementation of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION

[0023] The invention is described by reference to FIG. 1 that illustrates components A through D that are useful in the implementation of the invention.

[0024] The infrared heater assembly A includes, most basically, an outer infrared tub type heater that defines a central, axially extending fluid flow passage. This may be an outer quartz tube with a conductive outer surface coating and associated electrodes which, when energized, produces infrared radiation at the desired wave length. Because of the conductive coating's location and orientation, that radiation is directed radially inwardly toward the empty centrally axially extending flow passage. If the outer conductive coating on the outer tube is not sufficiently reflective, an over coating could be provided, as by very thin gold. Gold is useful because of its oxidation resistance and very high infrared reflectivity of approximately 95%. If desired, an insulative and protective outer tube or other layer could be put over the outer surface the central tube for thermal and mechanical protection, which would not affect its basic operation.

[0025] Alternatively, the assembly A could consist of an outer tube with no outer conductive coating, but with a reflective inner surface, and with a more or less conventional inner quartz heater tube running centrally and coaxially through it. This inner tube would contain heated coils and connectors to produce infrared radiative energy, but with no conductive or reflective coatings on either its inner or outer surface. It would be essentially like a commercially available quartz heater tube. The reflective inner surface on the inner surface of the outer tube could be provided by an additional inner tube layer of gold or the like, either directly or inserted separately as an additional tube or film, thereby avoiding a spraying or sputtering or dipping procedure. A close fitting extra inserted tube of other durable material coated on its inner surface could also serve to provide the radially inwardly facing reflector layer. An axially extending axial passage of annular cross section would thereby be defined between the conventional inner quartz heater tube and the reflective inner surface of the outer non-heated quartz tube. Suitable connectors could extend radially outwardly from the radially inner tube and out through, or otherwise outside of, the outer tube without significant blockage of the defined annular space. Quartz could be chosen for the outer tube, in this embodiment, for its durability and heat resistance, though other materials could serve. In this embodiment, radiant infrared energy would be radially outwardly directed from the heated coil inside the inner quartz heater tube, through its clear inner quartz tube and to the reflective inner surface of the outer tube, and then radially back, continuously through the annular space. This presents some obvious advantages, as the inner quartz tube could be conventional, and the outer surrounding quartz (or other suitable material) tube could. be easily and inexpensively produced. Both embodiments provide an axially extending central fluid flow passage that has an axially coextending (at least partially coextending) heating means to heat fluid pumped therethrough.

[0026] Either embodiment described above would have a suitable liquid heat transfer medium pumped through the central flow passage space by a pump D. This could be relatively small power, similar to an aquarium pump or the kinds of small pumps used for liquid computer cooling systems. Pump D would incorporate flow control valves in addition to its basic on-off controls. Ideally, the heat transfer fluid would be made infrared absorptive, either by dark coloration or by a contained suspension of radiant heat absorptive small granules or flakes. Flow into and out of the heater assembly A would be provided by tubing sealed to the ends of the central passage. In the alternative embodiment described, such tubing might have to be provided with a means for routing electrical wiring therethrough for the inner heater. This would not be necessary for the first embodiment, where the wiring is entirely outside the flow passage.

[0027] To extract useful cabin heating heat from the fluid so heated, a liquid to air heat exchanger B would be used. This could be relatively small, or as large as a typical vehicle heater core (another standard component) depending on need. In the absence of sufficient natural convective flow, a powered fan could be provided. This could also be a standard component, such as a computer air cooling fan or automotive heater fan.

[0028] In operation, temperature sensors and controls would be provided in a system to sense cabin temperature and heater assembly temperature, and send heated fluid through the assembly of heat exchanger B and fan C as needed. The heat exchanger B could also be fed by waste heat from any other available source in the vehicle, such as battery packs or traction motors, or a main heat pump system.

[0029] In an alternative embodiment of the invention, the radiant energy is microwave energy and the fluid within the system is water, with suitable antifreeze. This has a desirable characteristic in that water is readily available and is quite efficiently heated by radiated microwave energy. Microwave heaters are readily available and could easily be substituted for the infrared heater structure described with respect to the foregoing embodiment of the invention. A commercially important consideration in selection of the heating source is the energy efficiency of the transmission of energy into the carrier fluid. As has become well known, microwave energy is readily converted to heat in water. By directing microwave energy into water, the heating process is quite efficient. The heating chamber could enclose a microwave radiator outside of a segment of quartz tube that runs through the microwave chamber. Microwave chokes could be placed around the periphery of the quartz tube at its entry and exit locations into/from the microwave chamber to prevent microwave leakage. The system could be substantially the same as described above with respect to the infrared heating arrangement.

[0030] Variations of the disclosed embodiments within the spirit of the invention can be made. The heater assembly A can be scaled up or down, both in size, and in number of tube units, which could easily be ganged together and plumbed in parallel. Any new or improved pump, radiator or fan, or multiples thereof, could be incorporated with no change to the basic operation of heater assembly A. This would provide greater of lesser fluid and air flow rates as needed. The control system could be custom designed to allow variable control of all components, pump fan and heater, as desired.