US20120222429A1 - Vehicle air conditioner - Google Patents

Abstract

A vehicle air conditioner for a passenger compartment includes a power source, a radiator provided outside the passenger compartment, a heat medium passage through which heat medium is circulated between the power source and the radiator, a first peltier module having a first peltier device and a first heat exchanger, and a second peltier module having a second peltier device and a second heat exchanger. The first and second peltier devices each has a first surface and a second surface, one of the first surface and the second surface serves to release heat, the other of the first surface and the second surface serves to absorb heat. The first heat exchanger is thermally coupled to the first surface. The second heat exchanger is thermally coupled to the first surface. The heat medium passage is thermally coupled to the second surfaces of the first and second peltier devices.

Description

BACKGROUND OF THE INVENTION
• The present invention relates to a vehicle air conditioner.
• Japanese Unexamined Patent Application Publication No. 10-35268 discloses a vehicle air conditioner including a waste heat collector, a radiator, a peltier module, and a heat medium passage through which water as a heat medium is circulated.
• The waste heat collector functions to collect waste heat from a vehicle power source such as an electric motor. The peltier module has a peltier device with a first and a second surface one of which serves as heat releasing surface and the other of which serves as heat absorbing surface, a first heat exchanger thermally coupled to the first surface of the peltier device, and a second heat exchanger thermally coupled to the second surface of the peltier device. The heat medium passage connects the waste heat collector, the radiator, and the second heat exchanger of the peltier module.
• In the air conditioner, air conditioning of vehicle passenger compartment is done by switching the heat releasing and absorbing surfaces of the peltier device and also changing the water flow path in the heat medium passage.
• Specifically, when heating the passenger compartment, the peltier device is operated so that the first surface serves as the heat releasing surface and the second surface serves as the heat absorbing surface. The waste heat collector is connected to the second heat exchanger, while the second heat exchanger and the waste heat collector are disconnected from the radiator. Water flowing in the heat medium passage is heated by the heat in the waste heat collector. Heat of the water is absorbed through the second heat exchanger in the second surface of the peltier device. The heat thus absorbed is radiated from the first heat exchanger into the surrounding air. Then the heated air is supplied to the passenger compartment, so that heating of the passenger compartment is accomplished.
• When cooling the passenger compartment, the peltier device is operated so that the first surface serves as the heat absorbing surface and the second surface serves as the heat releasing surface. The radiator is connected to the second heat exchanger, while the second heat exchanger and the radiator are disconnected from the waste heat collector. Heat is absorbed through the first heat exchanger in the first surface of the peltier device and the air around the first exchanger is cooled. The cooled air is supplied to the passenger compartment, so that cooling of the passenger compartment is accomplished. The water in the heat medium passage is heated by the second heat exchanger to which heat is released from the peltier device, and then cooled in the radiator by heat exchange with the air outside the passenger compartment.
• Another known air conditioner is disclosed in Japanese Unexamined Patent Application Publication No. 2010-195287. The air conditioner includes a radiator, a first peltier module, a second peltier module, and a heat medium passage through which water is circulated. The heat medium passages connects the radiator, the first peltier module and the second peltier module.
• When heating the passenger compartment by the air conditioner, the first peltier module is operated so as to absorb heat from the water flowing in the heat medium passage and also release heat to the surrounding air. The heated air is supplied to the passenger compartment, so that heating of the passenger compartment is accomplished.
• When cooling, the second peltier module and the radiator are operated so that the second peltier module releases heat to the water flowing in the heat medium passage and also absorbs heat from the surrounding air. The cooled air is supplied to the passenger compartment, so that cooling of the passenger compartment is accomplished.
• When dehumidifying, the first and second peltier modules and the radiator are operated. Air is cooled and dehumidified by the second peltier module, and then the cooled air is heated by the first peltier module. The air at appropriately adjusted temperature is supplied to the passenger compartment, so that dehumidifying of the passenger compartment is accomplished.
• The air conditioner disclosed in the publication No. 10-35268 is complex in structure and large in size, which is disadvantageous in the installation in a vehicle. In addition, since the air cooled by the peltier module cannot be re-heated, the dehumidification causes a decrease in the efficiency of heating the compartment.
• In the air conditioner disclosed in the publication No. 2010-195287, on the other hand, although the dehumidification does not necessarily cause a decrease in the efficiency of cooling the compartment, the air conditioner requires an additional radiator for releasing heat from a vehicle power source. The provision of plural radiators results in an increased size of the air conditioner, which prevents easy installation of the air conditioner in a vehicle.
• The present invention is directed to providing a vehicle air conditioner that allows efficient air conditioning of a passenger compartment and easy installation in a vehicle.
SUMMARY OF THE INVENTION
• In accordance with an aspect of the present invention, a vehicle air conditioner for a passenger compartment of a vehicle includes a power source for driving the vehicle, a radiator provided outside the passenger compartment, a heat medium passage through which heat medium is circulated between the power source and the radiator, a first peltier module having a first peltier device and a first heat exchanger, and a second peltier module having a second peltier device and a second heat exchanger. The first peltier device has a first surface and a second surface, one of the first surface and the second surface serves to release heat, the other of the first surface and the second surface serves to absorb heat. The first heat exchanger is thermally coupled to the first surface. The second peltier device has a first surface and a second surface, one of the first surface and the second surface serves to release heat, the other of the first surface and the second surface serves to absorb heat. The second heat exchanger is thermally coupled to the first surface. The heat medium passage is thermally coupled to the second surface of the first peltier device and the second surface of the second peltier device.
• Other aspects and advantages of the invention will become apparent from the following description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 is a schematic view of a vehicle air conditioner according to an embodiment of the present invention;
• FIG. 2 is an enlarged fragmentary view of the air conditioner ofFIG. 1;
• FIG. 3 is a schematic view explaining the operation of the air conditioner ofFIG. 1 when heating a vehicle passenger compartment; and
• FIG. 4 is similar toFIG. 3, but explaining the operation of the air conditioner when dehumidifying the passenger compartment by re-heating the cooled air.
DETAILED DESCRIPTION OF THE EMBODIMENTS
• The following will describe the embodiment of the vehicle air conditioner according to the present invention with reference to the accompanying drawings. The air conditioner of the embodiment is intended for use in a vehicle for providing heating, cooling and dehumidifying of a passenger compartment of the vehicle.
• Referring toFIG. 1, the air conditioner includes anengine3, aradiator5,tubes7,9, a firstpeltier module11, and a secondpeltier module13. The first and secondpeltier modules11,13 are provided in aduct15 that is in communication with the passenger compartment.
• Theengine3 is the power source for driving the vehicle. Although not shown in the drawing, theengine3 has a water jacket where engine coolant flows for cooling theengine3. Theengine3 has an Inlet3A and anoutlet3B through which engine coolant flows into and out of the water jacket. Theengine3 may be replaced by an electric motor or a driver circuit such as power control unit (PCU). Alternatively, theengine3 combined with such electric motor or PCU may be used as the power source.
• Theradiator5 is a device where engine coolant flows and is cooled by heat exchange with the surrounding air. Theradiator5 has an Inlet5A and anoutlet5B through which engine coolant flows into and out of theradiator5. An electrically operatedfan5C is provided adjacent to theradiator5 and electrically connected to a controller (not shown). Engine coolant corresponds to the heat medium of the present invention.
• Theengine3 and theradiator5 are connected by thetubes7,9. Specifically, thetube7 connects between theoutlet3B of theengine3 and theinlet5A of theradiator5, and thetube9 connects between theoutlet5B of theradiator5 and theinlet3A of theengine3. Engine coolant is circulated between theengine3 and theradiator5A through thetubes7,9. An electrically operated pump P1 is provided in thetube7 and electrically connected to the aforementioned controller. The pump P1 may be provided in thetube9. Thetubes7,9 correspond to the heat medium passage of the present invention.
• Referring toFIG. 2, thefirst peltier module11 has afirst peltier device17 and afirst fin19. Thefirst peltier device17 has a firstinsulated substrate21, a secondinsulated substrate23, and pluralthermoelectric transducers25 held between the first and secondinsulated substrates21,23. In thefirst peltier device17, the firstinsulated substrate21 forms afirst surface17A from which heat is released, and the secondinsulated substrate23 forms asecond surface17B in which heat is absorbed. Thefirst peltier device17 is electrically connected to the controller. Thefirst peltier device17 is fixed at thefirst surface17A to thefirst fin19 in a thermally coupled manner, and disposed in contact at thesecond surface17B with thetube9 so that thefirst peltier module11 is thermally coupled to thetube9.
• Thefirst fin19 is formed by a plurality of heat radiation plates extending along the direction of air flow in theduct15 so as to provide a large surface area exposed to the air, specifically, to the outdoor air and the indoor air flowing through theduct15, while lowering the air flow resistance. In theduct15, heat exchange occurs between the heat radiation plates of thefirst fin19 and outdoor or indoor air. Thefirst fin19 is provided, for example, by a corrugated fin.
• Thesecond peltier module13 has asecond peltier device27 and asecond fin29. As with thefirst peltier device17, thesecond peltier device27 has a firstinsulated substrate21, a secondinsulated substrate23, and pluralthermoelectric transducers25 held between the first and secondinsulated substrates21,23. In thesecond peltier device27, the firstinsulated substrate21 forms afirst surface27A in which heat is absorbed, and the secondinsulated substrate23 forms asecond surface27B from which heat is released. Thesecond peltier device27 is electrically connected to the controller. The secondpettier device27 is fixed at thefirst surface27A to thesecond fin29 in a thermally coupled manner, and disposed in contact at thesecond surface27B with thetube9 so that thesecond peltier module13 is thermally coupled to thetube9.
• Thesecond fin29 has a structure similar to that of thefirst fin19 and also may be provided by a corrugated fin. The first andsecond fins19,29 correspond to the first and second heat exchangers, respectively, of the present invention.
• Theduct15 has a cylindricalmain portion31 and twocylindrical branch portions33,35 branched from themain portion31 at the upstream end thereof as seen in the air flow direction in theduct15. The end of thebranch portion33 remote from the branch forms anindoor air inlet33A that is opened to the passenger compartment of the vehicle, and the end of thebranch portion35 remote from the branch forms anoutdoor air inlet35A that is opened to the outdoor air outside the vehicle. An electrically operatedflapper37 is provided in the part of theduct15 where thebranch portions33,35 are joined. Themain portion31 is provided therein with an electrically operatedfan31A and in communication at the downstream side thereof with the passenger compartment. Thefan31A and theflapper37 are electrically connected to the controller. Theflapper37, which corresponds to the selector of the present invention, may be replaced by any suitable valves that are operable to open and close the respective indoor andoutdoor air inlets33A,35A with respect to themain portion31 of theduct15.
• The first andsecond peltier modules11,13 are provided in themain portion31 of theduct15 in a manner that the first andsecond peltier modules11,13 are thermally coupled to thetube9. Thesecond peltier module13 is provided downstream of thefirst peltier module11 as seen in the engine coolant flowing direction in thetube9. Themain portion31 of theduct15 hasholes15A,15B through which thetube9 is inserted.
• In the above-described vehicle air conditioner, while theengine3 is operating, the pump P1 and thefan5C are operated by the controller so that engine coolant is circulated through thetubes7,9 in the direction indicated by arrows inFIG. 3. Engine coolant heated by the waste heat of theengine3 flows from theoutlet3B of theengine3, flowing through thetube7 and then into theinlet5A of theradiator5. Heat exchange occurs between the engine coolant flowing in theradiator5 and the air around theradiator5, so that the heat of the engine coolant is radiated by the aid of thefan5C into the air outside the passenger compartment. The engine coolant thus cooled in theradiator5 then flows from theoutlet5B of theradiator5 through thetube9 and into theinlet3A of theengine3, cooling theengine3. While theengine3 is operating, the air conditioner of the present embodiment provide heating, cooling and dehumidifying of the passenger compartment of the vehicle as described below.
• When heating the passenger compartment, thefirst peltier device17 of thefirst peltier module11 is operated by the controller. Theflapper37 and thefan31A are also operated by the controller so that themain portion31 of theduct15 is connected to thebranch portion33 but disconnected from thebranch portion35, as shown inFIG. 3, and indoor air is introduced into themain portion31. In this case, thesecond surface17B or heat absorbing surface of thefirst peltier device17 absorbs heat from the engine coolant flowing in thetube9, while thefirst surface17A or heat releasing surface of thefirst peltier device17 releases heat to thefirst fin19. As a result, thefirst fin19 is heated, and the indoor air in contact with the heatedfirst fin19 in themain portion31 is heated, accordingly. The indoor air existing in the passenger compartment has a higher temperature than the outdoor air, and the indoor air is efficiently heated by thefirst fin19. Heated indoor air is supplied by thefan31A through theduct15 to the passenger compartment. In this way, heating of the passenger compartment is done.
• The engine coolant flowing in thetube9 and cooled by thefirst peltier device17 flows into theengine3 through itsinlet3A to be used to cool theengine3. In the air conditioner of the present embodiment wherein theengine3 is located downstream of thefirst peltier module11 as seen in the engine coolant flowing direction in thetubes7,9, theengine3 can be cooled by the engine coolant cooled by thefirst peltier device17 as well as by theradiator5. In other word, theengine3 can be efficiently cooled by utilizing the waste heat of thefirst peltier module11 during the heating operation of the air conditioner.
• When cooling the passenger compartment, thesecond peltier device27 of thesecond peltier module13 is operated, and theflapper37 and thefan31A are operated as in the case of the above heating operation so that indoor air is introduced into themain portion31 of theduct15. In this case, thesecond surface27B of thesecond peltier device27 releases heat to the engine coolant flowing in thetube9, while thefirst surface27A of thesecond peltier device27 absorbs heat from thesecond fin29. As a result, thesecond fin29 is cooled, and the indoor air in contact with thesecond fin29 in themain portion31 is cooled. The indoor air existing in the passenger compartment has a lower temperature than the outdoor air, and the indoor air is efficiently cooled by thesecond fin29. Cooled indoor air is supplied to the passenger compartment, so that cooling of the passenger compartment is done. The engine coolant flowing in thetube9 and receiving heat from thesecond peltier device27 is used to cool theengine3 and then cooled by theradiator5. That is, the waste heat of thesecond peltier module13 during the cooling operation is released along with the waste heat of theengine3 into the air outside the passenger compartment.
• When dehumidifying the passenger compartment, both of the first andsecond peltier modules11,13 are operated by the controller, as shown inFIG. 4. Theflapper37 and thefan31A are also operated so that themain portion31 is connected to thebranch portion35 but disconnected from thebranch portion33 and the outdoor air is introduced into themain portion31. In this case, the outdoor air cooled by thesecond fin29 and dehumidified is in turn heated by thefirst fin19 to an appropriate temperature. The outdoor air which has a lower humidity than the indoor air is efficiently cooled and dehumidified by thesecond fin29. The outdoor air adjusted at an appropriate temperature is supplied to the passenger compartment for dehumidifying of the passenger compartment, as well as for appropriate air-conditioning of the passenger compartment. The engine coolant releasing heat to thefirst peltier device17 and receiving heat from thesecond peltier device27 while flowing in thetube9 is introduced into theengine3 through itsinlet3A and used to cool theengine3. When there is no need to heat the dehumidified outdoor air, no operation of the firstpettier module11 is performed.
• In the vehicle air conditioner of the present embodiment, heating and cooling of the passenger compartment can also be accomplished by using heated outdoor air and cooled outdoor air, respectively, which makes it easy to keep the humidity of the passenger compartment during the heating and cooling operation when the outdoor air has a lower humidity than the indoor air. Dehumidifying of the passenger compartment can also be accomplished by using the dehumidified indoor air. In a weather condition that the outdoor air has a higher humidity than the indoor air, the use of such dehumidified indoor air allows efficient dehumidifying of the passenger compartment and makes it easy to keep the humidity of the passenger compartment by circulating the indoor air between themain portion31 of theduct15 and the passenger compartment. Theflapper37 may be positioned so that both of thebranch portions33,35 are connected to themain portion31 of theduct15, which allows air conditioning of the passenger compartment using the outdoor air and the indoor air mixed together in a desired mixing ratio.
• As described above, according to the vehicle air conditioner of the present embodiment, there is no need to change the flow path of the engine coolant flowing in thetubes7,9 depending on the operating modes, including heating, cooling or dehumidifying of the passenger compartment. In the air conditioner wherein theengine3 is connected to thetubes7,9 and cooled by the engine coolant flowing in thetubes7,9, not only the waste heat of the first andsecond peltier modules11,13 during the air conditioning, but also the waste heat of theengine3 are transferred by the engine coolant and radiated from theradiator5 into the air outside the passenger compartment. Thus, the air conditioner of the embodiment requires no additional radiator to cool theengine3, which results in a smaller size of the air conditioner.
• Thus, the vehicle air conditioner of the present embodiment allows efficient air conditioning of the passenger compartment and easy installation of the air conditioner in a vehicle.
• Particularly in the air conditioner of the present embodiment whereinsecond peltier module13 is provided downstream of thefirst peltier module11 as seen in the engine coolant flowing direction in thetube9, since thesecond peltier device27 releases heat to the engine coolant that has been cooled by thefirst peltier device17 when dehumidifying the vehicle passenger compartment, a larger amount of heat is absorbed in the heat absorbing surface of thesecond peltier device27 and hence thesecond fin29 is sufficiently cooled. The outdoor air is cooled efficiently and dehumidified sufficiently by such cooledsecond fin29, resulting in efficient dehumidification of the passenger compartment. The cooled outdoor air can be re-heated by thefirst fin19, which does not cause a decrease in the efficiency of air conditioning of the passenger compartment.
• In the air conditioner of the present embodiment, the first andsecond peltier modules11,13 are provided in theduct15 that is in communication with the passenger compartment. Theduct15 is provided with theflapper37 which allows selective supply of the outdoor air or the indoor air to the passenger compartment. Efficient air conditioning of the passenger compartment is accomplished by heating, cooling or dehumidifying the outdoor or the indoor air selected as required.
• It is to be understood that the present invention is not limited to the above-described embodiments, but it may be modified in various ways without departing from the scope of the invention.
• For example, the engine coolant flowing through thetubes7,9 may be used not only to cool theengine3 but also to cool any other component such as a battery provided in a vehicle and thermally coupled to thetubes7,9.
• The number of thefirst peltier modules11 and of thesecond peltier modules13 may be two or more. The number of thefirst peltier module11 and the number of thesecond peltier module13 need not necessarily be the same, but they may be different from each other.
• Thefirst fin19 and thesecond fin29 may be replaced by a first heat exchanger and a second heat exchanger, respectively, through which water circulates. In such a case, the water flowing in the first heat exchanger receives heat from thefirst peltier device17 and hence is heated. Outdoor air or indoor air in themain portion31 of theduct15 is heated by heat exchange with such heated water. Similarly, the water flowing in the second heat exchanger releases heat to thesecond peltier device27 and is cooled. Outdoor air or indoor air in themain portion31 of theduct15 is cooled by heat exchange with such cooled water.
• The present invention is applicable to an air conditioner for use in an engine powered vehicle, a hybrid vehicle driven by an engine and an electric motor, and an electric vehicle driven by an electric motor.

Claims (4)

1. A vehicle air conditioner for a passenger compartment of a vehicle, comprising:

a power source for driving the vehicle;

a radiator provided outside the passenger compartment;

a heat medium passage through which heat medium is circulated between the power source and the radiator;

a first pettier module having a first pettier device and a first heat exchanger, the first pettier device having a first surface and a second surface, one of the first surface and the second surface serving to release heat, the other of the first surface and the second surface serving to absorb heat, the first heat exchanger being thermally coupled to the first surface; and

a second pettier module having a second pettier device and a second heat exchanger, the second pettier device having a first surface and a second surface, one of the first surface and the second surface serving to release heat, the other of the first surface and the second surface serving to absorb heat, the second heat exchanger being thermally coupled to the first surface,

wherein the heat medium passage is thermally coupled to the second surface of the first pettier device and the second surface of the second pettier device.

2. The vehicle air conditioner according toclaim 1, wherein the first surface of the first pettier device serves to release heat and the second surface of the first pettier device serves to absorb heat so that the first pettier module provides heating of the passenger compartment, and the first surface of the second pettier device serves to absorb heat and the second surface of the second pettier device serves to release heat so that the second pettier module provides cooling of the passenger compartment.

3. The vehicle air conditioner according toclaim 2, wherein the second pettier module is provided downstream of the first pettier module as seen in heat medium flowing direction in the heat medium passage.

4. The vehicle air conditioner according toclaim 2, wherein the first peltier module and the second peltier module are provided in a duct communicating with the passenger compartment, the duct being provided with a selector that allows selective supply of outdoor air or indoor air to the passenger compartment.

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