Power generation device and refrigerator vehicle provided with same

Abstract

Provided are: a power generation device capable of generating power by using waste heat from an engine and simplifying the structure; and a refrigerator vehicle provided with the same. Since electric power generated by a generator 26 is stored in a second battery 17 of a refrigerating device 10, and a motor 16 for driving a compressor 11 in a refrigerating circuit 10a of the refrigerating device 10 is driven by the electric power from the second battery 17, the electric power for driving the compressor 11 can be generated by using waste heat (heat from cooling water) of an engine 4. In addition, in a second circulation mode, since an existing radiator 5 provided to the vehicle can be used as a cooler for cooling the working fluid of a condenser 23, and cooling water for cooling the engine 4 can be cooled by the condenser 23, it is not necessary to provide a dedicated cooler for the condenser 23 and it is possible to achieve simplification of the structure of the power generation device 20.

Description

Power generating equipment and refrigerated vehicle equipped with the same

[0001] The present invention relates to a power generating device that generates electric power for driving a compressor of a refrigeration unit for a refrigeration vehicle, for example, and a refrigeration vehicle equipped with the same.

[0002] Conventionally, a known refrigerated vehicle for transporting frozen foods and the like is a truck-type vehicle equipped with an insulated refrigerator compartment, and the interior of the refrigerator compartment is cooled by a refrigeration device (see, for example, Patent Document 1).

[0003] In this refrigerated vehicle, the compressor of the refrigeration unit is driven by engine power, but since the compressor cannot be driven when the engine is stopped, the temperature inside the refrigerator compartment rises when the vehicle is stopped for a long period of time, which may cause deterioration of the contents inside the refrigerator compartment. Therefore, as a way to cool the refrigerator compartment even when the engine is stopped, a device is known in which electricity is stored in a battery by an engine-driven generator, and the motor that rotates the compressor is driven by the battery power (see, for example, Patent Document 2).

[0004] JP 2019-20039 A JP 2006-290116 A

[0005] However, in the case of the above-mentioned conventional refrigerated vehicles, in which the power source of the compressor of the refrigeration unit is the engine power or the electricity generated by the engine power is used, the fuel of the vehicle is consumed to drive the compressor, which causes problems such as a deterioration in fuel consumption rate and an increase in the amount of heat released into the atmosphere.

[0006] In addition, truck-type vehicles such as refrigerated trucks have larger engines and generate more heat than passenger cars, but the waste heat is not effectively utilized and is instead released into the atmosphere. If this waste heat could be recovered as an energy resource and used to generate electricity, it would be possible to contribute to reducing fuel costs and curbing global warming. In this case, if existing equipment in the vehicle could be used as part of the equipment that makes up the power generation system, the structure of the power generation system could be simplified, which would be desirable when installing it in a vehicle.

[0007] The present invention has been made in consideration of the above-mentioned problems, and its object is to provide a generator that can generate electricity by utilizing waste heat from an engine and that can simplify the structure, and a refrigerated vehicle equipped with the generator.

[0008] In order to achieve the above object, the present invention provides a power generation device that utilizes an engine that drives a driven object and a radiator that can exchange heat with the outside for a heat medium for cooling the engine, the power generation device including an evaporator that evaporates a working fluid, an expander that rotates by the expansion of the working fluid evaporated by the evaporator, a generator that generates electricity by the rotation of the expander, a condenser that condenses the working fluid that flows out of the expander, and a pump that circulates the working fluid that flows out of the condenser to the evaporator, and a heat medium circulation circuit having a switching means that can switch between a first circulation mode in which the heat medium that flows out of the engine flows to the radiator and then into the engine, and a second circulation mode in which the heat medium that flows out of the engine flows to the evaporator without flowing to the radiator and then into the engine, and the heat medium that flows out of the radiator flows to the condenser and then into the radiator.

[0009] As a result, in the first flow mode, the heat medium that cools the engine is cooled by the radiator. Also, in the second flow mode, the heat of the heat medium heated by the engine evaporates the working fluid in the evaporator, which rotates the expander and causes the generator to generate electricity, thereby generating electricity using the waste heat of the engine. In this case, the radiator is used as a cooler to cool the working fluid in the condenser, and the heat medium that cools the engine is cooled by the evaporator.

[0010] In order to achieve the above object, the present invention provides a refrigerated vehicle having a vehicle engine, a radiator capable of exchanging heat with the outside for cooling the heat medium for cooling the engine, a refrigeration circuit for cooling the inside of an on-board refrigerator, a motor for driving a compressor of the refrigeration circuit, and a battery for driving the motor, and the vehicle is provided with a power generation device for generating electricity to be stored in the battery, and is configured so that when the amount of electricity stored in the battery is equal to or greater than a predetermined amount, the compressor is driven by the motor, and when the amount of electricity stored in the battery is less than the predetermined amount, the compressor is driven by the engine.

[0011] As a result, in addition to the action of the power generation device, if the battery's stored power is less than a specified amount, the compressor is driven by the engine, making it possible to operate the refrigeration circuit even if the battery's stored power is insufficient, for example, when the thermal load on the refrigeration circuit is high.

[0012] The power generation system of the present invention can generate electricity using engine waste heat. For example, when generating power to drive a compressor in a refrigeration circuit of a refrigerated truck, the power required to drive the compressor can be obtained without consuming fuel from the vehicle, thereby preventing a deterioration in fuel consumption and an increase in the amount of heat released into the atmosphere. In particular, truck-type vehicles such as refrigerated trucks have larger engines and generate more heat than passenger cars. However, the present invention can effectively utilize the waste heat in the refrigeration system of the refrigerated truck, thereby contributing to reduced fuel costs and the prevention of global warming. In this case, in the second flow mode, the vehicle's existing radiator can be used as a cooler for cooling the working fluid in the condenser, eliminating the need for a dedicated cooler for the condenser and simplifying the system's construction. When power generation is not being performed, such as when the battery is fully charged, when the coolant temperature is 100°C or higher, or when the power generation device malfunctions, the first flow mode can be used to cool the heat medium that cools the engine using the radiator, which has the advantage of allowing the radiator to function as its original engine cooling device.

[0013] Furthermore, according to the refrigerated vehicle of the present invention, in addition to the effect of the power generation device, the refrigeration circuit can be operated even when the battery's stored power is insufficient, for example, when the thermal load of the refrigeration circuit is large, so the inside of the refrigerator can be constantly cooled.

[0014] Schematic side view of a refrigerated vehicle equipped with an on-board power generating unit, showing one embodiment of the present invention; Schematic plan view of a refrigerated vehicle equipped with an on-board power generating unit; Circuit configuration diagram of the refrigeration unit; Circuit configuration diagram of the power generating unit in a first flow mode; Circuit configuration diagram of the power generating unit in a second flow mode; Block diagram of the power generating unit;

[0015] 1 to 6 show an embodiment of the present invention, which shows a power generating device for generating electric power for driving a compressor of a refrigeration unit for a refrigeration vehicle.

[0016] The refrigerated vehicle 1 shown in the figure is a well-known transport vehicle having a thermally insulated refrigerator box 3 mounted on a truck-type body 2, and is equipped with an engine 4 that drives the vehicle as a driving object, and a radiator 5 disposed at the front of the body 2 that cools the engine 4 as a heat medium. A fan 5a is provided on the rear side of the radiator 5, and the coolant in the radiator 5 is cooled by heat exchange with outside air drawn in from the front side of the radiator 5 by the fan 5a. A first battery 6 that supplies power to the vehicle's electrical system is provided under the floor of the refrigerated vehicle 1, and electricity is stored in the first battery 6 by a generator (not shown) driven by the engine 4.

[0017] The refrigerated vehicle 1 also includes a refrigeration unit 10 that cools the inside of the refrigerator 3 and a power generation unit 20 that generates electricity to be supplied to the refrigeration unit 10 .

[0018] The refrigeration system 10 includes a refrigeration circuit 10a in which refrigerant discharged from a compressor 11 flows sequentially through a condenser 12, an expansion valve 13, and an evaporator 14, and is then drawn into the compressor 11. The refrigerant flowing through the condenser 12 exchanges heat with outside air, and the refrigerant flowing through the evaporator 14 exchanges heat with the air inside the refrigerator 3, thereby cooling the interior of the refrigerator 3. The condenser 12 and the evaporator 14 are housed in a refrigeration unit 10b attached to the upper front of the refrigerator 3, and the refrigeration unit 10b circulates the air inside the refrigerator 3 cooled by the evaporator 14, as indicated by the solid arrows in Figure 1. Furthermore, an interior temperature sensor 15 is provided inside the refrigerator 3 to detect the temperature inside the refrigerator.

[0019] The refrigeration system 10 also includes a motor 16 that drives the compressor 11 and a second battery 17 that drives the motor 16. The motor 16 has a rotating shaft 16a connected to a rotating shaft 11a of the compressor 11 via a pair of pulleys 16b and a belt 16c, and a first electromagnetic clutch 18 enables or disables power transmission between the rotating shaft 11a of the compressor 11 and the pulley 16b. The rotating shaft 11a of the compressor 11 is also connected to the engine 4 via another pair of pulleys 11b and a belt 11c, and a second electromagnetic clutch 19 enables or disables power transmission between the rotating shaft 11a of the compressor 11 and the pulley 11b.

[0020] The power generation device 20 includes an evaporator 21 that evaporates a working fluid (e.g., chlorofluorocarbon) using cooling water flowing out of the engine 4, an expander 22 that rotates using the working fluid evaporated by the evaporator 21, a condenser 23 that condenses the working fluid flowing out of the expander 22 using cooling water flowing out of the radiator 5, a heat exchanger 24 that exchanges heat between the working fluid flowing out of the expander 22 and the working fluid flowing out of the condenser 23, a main pump 25 that circulates the working fluid flowing out of the condenser 23 through the heat exchanger 24 and then into the evaporator 21, a generator 26 that rotates using the expander 22, and a cooling water distribution circuit 27 that exchanges heat between the cooling water of the engine 4 and the evaporator 21 and the condenser 23, and stores electric power generated by the generator 26 in the second battery 17. That is, the power generation device 20 includes the evaporator 21, the expander 22, the condenser 23, the heat exchanger 24, and the main pump 25 to form a Rankine cycle.

[0021] The evaporator 21 is provided in a flow path of the working fluid, and heats and evaporates the working fluid flowing inside by exchanging heat with the cooling water flowing out from the engine 4 .

[0022] The expander 22 has an inlet side for the working fluid connected to the evaporator 21 side, and is coaxially connected to the rotating shaft of the generator 26. As the expander 22, for example, a well-known scroll type expander can be used.

[0023] The condenser 23 cools and condenses the working fluid flowing inside by exchanging heat with the cooling water flowing out from the radiator 5, and the inlet side of the working fluid side flow path of the condenser 23 is connected to the outlet side flow path of the expander 22 via a heat exchanger 24.

[0024] The heat exchanger 24 heats the working fluid flowing out from the condenser 23 by heat exchange with the high-temperature working fluid flowing out from the expander 22, and the outlet side flow path of the working fluid flowing out from the condenser 23 is connected to the inlet side of the evaporator 21.

[0025] The suction side of the main pump 25 is connected to the outflow side of the condenser 23, and the discharge side is connected to the heat exchanger 24. A one-way valve 25a is provided in the flow path between the main pump 25 and the condenser 23, and the one-way valve 25a regulates the reverse flow of the working fluid. A collector tank 25b serving as a reservoir for storing the working fluid is provided between the main pump 25 and the one-way valve 24a, so that the working fluid remains stored in the flow path between the main pump 25 and the one-way valve 25a and in the collector tank 25b even after the main pump 25 has stopped.

[0026] The generator 26 has its rotary shaft connected to the expander 22 and generates electricity when rotated by the expander 22. The generator 26 is also connected to the second battery 17 via a charging circuit 26a.

[0027] The cooling water circulation circuit 27 is configured to circulate the cooling water by a cooling water pump (not shown) driven by the engine 4, and the cooling water pump increases the flow rate of the cooling water when the rotation speed of the engine 4 increases and decreases the flow rate of the cooling water when the rotation speed of the engine 4 decreases.

[0028] In the coolant circulation circuit 27, the outlet flow path of the engine 4 branches off and is connected to the inlet side of the radiator 5 and the coolant inlet side of the evaporator 21, and the coolant outlet flow path of the evaporator 21 and the outlet flow path of the radiator 5 merge together and are connected to the inlet side of the engine 4. In the coolant circulation circuit 27, the outlet flow path of the radiator 5 branches off and is connected to the coolant inlet side of the condenser 23, and the coolant outlet side of the condenser 23 is connected to merge with the inlet flow path of the radiator 5, and a pump 27 a is provided in the coolant outlet flow path of the condenser 23.

[0029] Furthermore, the cooling water circulation circuit 27 is provided with a first solenoid valve 27b that opens and closes the inlet side flow path of the radiator 5, a second solenoid valve 27c that opens and closes the cooling water inlet side flow path of the evaporator 21, a third solenoid valve 27d that opens and closes the flow path between the branching portion of the outlet side flow path of the radiator 5 to the condenser 23 and the inlet side of the engine 4, and a fourth solenoid valve 27e that opens and closes the flow path between the branching portion of the outlet side flow path of the radiator 5 to the condenser 23 and the inlet side of the condenser 23.

[0030] The coolant distribution circuit 27 is configured to be switchable between a first distribution mode in which the coolant flowing out of the engine 4 passes through the radiator 5 and then flows into the engine 4, and a second distribution mode in which the coolant flowing out of the engine 4 passes through the evaporator 21 and then flows into the engine 4 without passing through the radiator 5, and the coolant flowing out of the radiator 5 passes through the condenser 23 and then flows into the radiator 5. In the coolant distribution circuit 27, when the first distribution mode is selected, the first solenoid valve 27c is opened and the second solenoid valve 27c is closed, and the third solenoid valve 27d is opened and the fourth solenoid valve 27e is closed. When the second distribution mode is selected, the first solenoid valve 27c is closed and the second solenoid valve 27c is opened, and the third solenoid valve 27d is closed and the fourth solenoid valve 27e is opened. That is, the first to fourth solenoid valves 27b, 27c, 27d, and 27e constitute a switching means for switching between the first flow mode and the second flow mode. Although the solenoid valves are used as the switching means in this embodiment, three-way valves may also be used.

[0031] The coolant flow circuit 27 is also provided with a flow rate sensor 27 f that detects the flow rate of the coolant flowing out from the engine 4 , and a coolant temperature sensor 27 g that detects the temperature of the coolant flowing out from the engine 4 .

[0032] A power generation unit 20a is provided on the underside of the vehicle body 2, and the power generation unit 20a houses an evaporator 21, an expander 22, a condenser 23, a heat exchanger 24, a main pump 25, a generator 26, and a pump 27a. Also, a first battery 6 and a second battery 17 are arranged on the underside of the vehicle body 2.

[0033] The power generation device 20 includes a motor drive circuit 28 that activates and stops the motor 16, a first clutch drive circuit 29 that connects and disconnects the first electromagnetic clutch 18, a second clutch drive circuit 30 that connects and disconnects the second electromagnetic clutch 19, and a pump drive circuit 31 that activates and stops the main pump 25 and the pump 27a of the coolant distribution circuit 27. Each of the drive circuits 28, 29, 30 is connected to the second battery 17 and determines whether the amount of electricity stored in the second battery 17 is a first amount of electricity W1 (e.g., 5% or more but less than 95%), a second amount of electricity W2 (e.g., 95% or more), or a third amount of electricity W3 (e.g., less than 5%).

[0034] The motor drive circuit 28 is configured to operate the motor 16 when the amount of electricity stored in the second battery 17 is the first amount of electricity W1 or the second amount of electricity W2 and the temperature detected by the internal temperature sensor 15 is higher than a predetermined internal temperature setting (e.g., minus 25°C), and to stop the motor 16 when the amount of electricity stored in the second battery 17 is the third amount of electricity W3.

[0035] When the amount of electricity stored in the second battery 17 is the first amount of electricity W1 or the second amount of electricity W2 and the temperature detected by the internal temperature sensor 15 is equal to or higher than the set internal temperature, the first clutch drive circuit 29 connects the first electromagnetic clutch 18 to transmit the driving force of the motor 16 to the compressor 11. When the amount of electricity stored in the second battery 17 is the third amount of electricity W3, the first clutch drive circuit 29 disconnects the first electromagnetic clutch 18.

[0036] The second clutch drive circuit 30 is configured to connect the second electromagnetic clutch 19 to transmit the driving force of the engine 4 to the compressor 11 when the amount of electricity stored in the second battery 17 is the third amount of electricity W3 and the temperature detected by the internal temperature sensor 15 is equal to or higher than T1. When the amount of electricity stored in the second battery 17 is the first amount of electricity W1 or the second amount of electricity W2, the second clutch drive circuit 30 disconnects the second electromagnetic clutch 19.

[0037] When the amount of electricity stored in the second battery 17 is the first amount of electricity W1 or the third amount of electricity W3, and when the temperature detected by the coolant temperature sensor 27f is equal to or higher than a predetermined temperature T1 (e.g., 80° C.) and the flow rate of the coolant detected by the flow rate sensor 27g is equal to or higher than a predetermined flow rate Q1 (e.g., 10 liters per minute), the pump drive circuit 31 operates the main pump 25 and the pump 27a of the coolant distribution circuit 27. When the amount of electricity stored in the second battery 17 is equal to the second amount of electricity W2, the pump drive circuit 31 stops the main pump 25 and the pump 27a of the coolant distribution circuit 27. Furthermore, first to fourth solenoid valves 27b, 27c, 27d, and 27e are connected to the pump drive circuit 31, and when the pumps 25 and 27a are stopped by the pump drive circuit 31, the solenoid valves 27b, 27c, 27d, and 27e open and close so that the cooling water circulation circuit 27 is in the first circulation mode, and when the pumps 25 and 27a are operated by the pump drive circuit 31, the solenoid valves 27b, 27c, 27d, and 27e open and close so that the cooling water circulation circuit 27 is in the second circulation mode.

[0038] Furthermore, when the amount of stored electricity in the second battery 17 reaches a third amount of stored electricity W3, the second battery 17 is charged with the power of the first battery 6.

[0039] In the power generation device 20 configured as described above, when power generation by the power generation device 20 is not being performed, the coolant flow circuit 27 is set to the first flow mode. As a result, in the coolant flow circuit 27, the coolant flowing out of the engine 4 by a coolant pump (not shown) of the engine 4 flows into the radiator 5, where it is cooled by heat exchange with external air and then flows into the engine 4, as shown by the solid arrows in Figure 4.

[0040] Next, when generating electricity using the power generation device 20, the coolant distribution circuit 27 is set to the second distribution mode. As a result, in the coolant distribution circuit 27, the coolant flowing out of the engine 4 by a coolant pump (not shown) of the engine 4 flows through the evaporator 21, and heat is exchanged between the working fluid in the evaporator 21 and the coolant, heating the working fluid, as shown by the solid arrows in Figure 5. The coolant flowing out of the evaporator 21 flows into the engine 4, where it is heated by waste heat from the engine 4 and then flows into the evaporator 21.

[0041] In the coolant flow circuit 27 in the second flow mode, the pump 27a is operated so that the coolant flowing out from the radiator 5 flows through the condenser 23, and the working fluid in the condenser 23 exchanges heat with the coolant, thereby cooling the working fluid. The coolant flowing out from the condenser 23 flows into the radiator 5, where it is cooled by heat exchange with the outside air, and then flows into the condenser 23.

[0042] Meanwhile, in the working fluid circuit of the power generation device 20, as shown by the dashed arrow in Fig. 5 , the working fluid that has been heated and evaporated in the evaporator 21 flows into the expander 22 and expands within the expander 22. This causes the expander 22 to rotate due to the expansion of the working fluid, which drives the generator 26. Next, the working fluid flowing out of the expander 22 flows through the heat exchanger 24 and into the condenser 23, where it is condensed by heat exchange with the cooling water in the cooling water distribution circuit 27. The working fluid in a liquid state flowing out of the condenser 23 is drawn into the main pump 25 and discharged to the heat exchanger 24 side, where it is heated by heat exchange with the working fluid flowing out of the expander 22 in the heat exchanger 24, and then flows into the evaporator 21 side.

[0043] The power generation device 20 operates in the following manner depending on the amount of electricity stored in the second battery 17 .

[0044] First, when the amount of electricity stored in the second battery 17 is the first amount of electricity W1, a sufficient amount of electricity (e.g., 5% or more) is stored to drive the compressor 11, and therefore the compressor 11 of the refrigeration system 10 is driven by the motor 16 via the motor drive circuit 28 and the first and second clutch drive circuits 29, 30. At this time, the pump drive circuit 31 operates the main pump 25 and the pump 27a of the coolant distribution circuit 27, causing the expander 22 to rotate, generating electricity with the generator 26 and storing electricity in the second battery 17. In this case, if the temperature of the coolant flowing out of the engine 4 is lower than the predetermined temperature T1 or the flow rate of the coolant is lower than the predetermined flow rate Q1, sufficient heat cannot be obtained to evaporate the working fluid in the evaporator 21, so the main pump 25 and the pump 27a of the coolant distribution circuit 27 are stopped, and power generation by the generator 26 is stopped. Even if the flow of working fluid stops due to the main pump 25 being stopped, the working fluid in the inlet flow path of the main pump 25 is prevented from flowing back by the one-way valve 25a and is stored in the collector tank 25b. Therefore, when the main pump 25 starts operating, the working fluid stored in the inlet flow path of the main pump 25 is quickly sucked into the main pump 25 by the one-way valve 25a and the collector tank 25b.

[0045] Furthermore, when the amount of electricity stored in the second battery 17 is a second amount of electricity stored W2 (for example, 95% or more), the second battery 17 is nearly fully charged, and the load on the generator 26 (the load on the expander 22) is significantly reduced, so the pump drive circuit 31 stops the main pump 25 and the pump 27a of the cooling water distribution circuit 27. This stops the expander 22 and prevents the expander 22 from running idle due to the reduced load. Furthermore, the motor drive circuit 28 and the first and second clutch drive circuits 29, 30 drive the compressor 11 of the refrigeration system 10 with the motor 16.

[0046] On the other hand, when the amount of electricity stored in the second battery 17 is the third storage amount W3, the amount of electricity stored to drive the compressor 11 is insufficient (e.g., less than 5%). Therefore, the motor drive circuit 28 and the first and second clutch drive circuits 29, 30 switch the drive of the compressor 11 from the motor 16 to the engine 4, and the compressor 11 is driven by the engine 4. At this time, the second battery 17 is charged with power from the first battery 6 until the amount of electricity stored reaches the first storage amount W1. The pump drive circuit 31 also operates the main pump 25 and the pump 27a of the coolant distribution circuit 27, causing the generator 26 to generate electricity and store electricity in the second battery 17. If the temperature of the coolant in the coolant distribution circuit 27 is lower than the predetermined temperature T1 or the flow rate of the coolant is lower than the predetermined flow rate Q1, power generation by the generator 26 is stopped, as described above.

[0047] As described above, the power generation device 20 of this embodiment comprises an evaporator 21 that evaporates the working fluid by heat exchange with the cooling water of the vehicle's engine 4, an expander 22 that rotates by the expansion of the working fluid evaporated by the evaporator 21, a generator 26 that generates electricity by the rotation of the expander 22, a condenser 23 that condenses the working fluid flowing out from the expander 22, a main pump 25 that sucks in the working fluid flowing out from the condenser 23 and discharges it to the evaporator 21 side, and a cooling water distribution circuit 27 for heat exchanging the cooling water of the engine 4 with the evaporator 21 and the condenser 23. The electricity generated by the generator 26 is stored in the second battery 17 of the refrigeration device 10, and the motor 16 that drives the compressor 11 of the refrigeration circuit 10a of the refrigeration device 10 is driven by the power of the second battery 17. Therefore, the electricity to drive the compressor 11 can be generated using the waste heat of the engine 4 (heat of the cooling water).

[0048] This allows power to be obtained to drive the compressor 11 without consuming vehicle fuel, and has the advantage of not causing a deterioration in fuel consumption rate or an increase in the amount of heat released into the atmosphere. In particular, truck-type vehicles such as refrigerated trucks have larger engines and generate more heat than passenger cars, but the present invention allows the waste heat to be effectively used in the refrigeration device 10 of the refrigerated truck 1, thereby contributing to reducing fuel costs and suppressing global warming.

[0049] Furthermore, the coolant flow circuit 27 is configured to be switchable between a first flow mode in which the coolant flowing out of the engine 4 flows through the radiator 5 and then flows into the engine 4, and a second flow mode in which the coolant flowing out of the engine 4 flows through the evaporator 21 without flowing through the radiator 5 and then flows into the engine 4, and the coolant flowing out of the radiator 5 flows through the condenser 23 and then flows into the radiator 5. Therefore, in the second flow mode, the existing radiator 5 provided in the vehicle can be used as a cooler for cooling the working fluid in the condenser 23. This eliminates the need to provide a dedicated cooler for the condenser 23, thereby simplifying the structure of the power generation device 20.

[0050] In this case, when the power generation device 20 is not generating electricity (when the pumps 25, 27a are stopped), the solenoid valves 27b, 27c, 27d, and 27e switch the flow paths so that the coolant flow circuit 27 is in the first flow mode, and when the power generation device 20 is generating electricity (when the pumps 25, 27a are operating), the solenoid valves 27b, 27c, 27d, and 27e switch the flow paths so that the coolant flow circuit 27 is in the second flow mode. Therefore, when the power generation device 20 is stopped, for example, when the battery 17 is fully charged, when the coolant temperature reaches 100°C or higher, or when the power generation device 20 malfunctions, the first flow mode is selected, so that the coolant for the engine 4 can be cooled by the radiator 5. This allows the radiator 5 to function as an engine cooling device, which is an inherent feature of the system. This has the advantage of not interfering with the running of the vehicle even when the coolant for the engine 4 is not cooled by the power generation device 20.

[0051] In addition, a heat exchanger 24 is provided to exchange heat between the working fluid flowing out of the expander 22 and the working fluid flowing out of the condenser 23, so that the heat of the working fluid flowing out of the expander 22 can be absorbed by the working fluid flowing into the evaporator 21, promoting evaporation of the working fluid in the evaporator 21 and increasing the efficiency of the thermal cycle.

[0052] Furthermore, when the amount of electricity stored in the second battery 17 is equal to or greater than a predetermined amount (e.g., 5%), the compressor 11 is driven by the motor 16, and when the amount of electricity stored in the second battery 17 is less than the predetermined amount, the compressor 11 is driven by the power of the engine 4. Therefore, even when the amount of electricity stored in the second battery 17 is insufficient, for example, when the thermal load of the refrigeration device 10 is large, the refrigeration device 10 can be operated and the interior of the refrigerator 3 can be constantly cooled. In this case, when the amount of electricity stored in the second battery 17 is less than the predetermined amount, the power of the first battery 6 is supplied to the second battery 17. Therefore, the power for driving the main pump 25 can be secured from the first battery 6, and a stop of operation of the power generation device 20 due to depletion of the second battery 17 can be avoided.

[0053] Furthermore, a one-way valve 25a that restricts reverse flow of the working fluid is provided between the condenser 23 and the main pump 25, so that even if the flow of the working fluid stops due to a stop of the main pump 25, the one-way valve 25a allows the working fluid to be stored in the inlet flow path of the main pump 25. This allows the working fluid to be quickly drawn into the main pump 25 when the main pump 25 starts operating, and the power generation device 20 can be reliably started up even if the main pump 25 is stopped for a long time.

[0054] In this case, a collector tank 25b for storing the working fluid is provided between the main pump 25 and the one-way valve 25a, so that a larger amount of working fluid can be stored between the main pump 25 and the one-way valve 25a, and the power generation device 20 can be started up more quickly when the main pump 25 starts operating.

[0055] In the above embodiment, the pumps 25, 27a are stopped when the temperature of the cooling water in the cooling water circulation circuit 27 is lower than the predetermined temperature T1 or when the flow rate of the cooling water is lower than the predetermined flow rate Q1. However, the pumps 25, 27a may be stopped only when the temperature of the cooling water in the cooling water circulation circuit 27 is lower than the predetermined temperature T1 or only when the flow rate of the cooling water is lower than the predetermined flow rate Q1.

[0056] In the above embodiment, each expander 22 is coaxially connected to the rotary shaft of the generator 26, but they may be rotated integrally with each other by means of gears.

[0057] Furthermore, in the above embodiment, the power of the motor 16 is transmitted to the compressor 11 via the pulley 16b and the belt 16c, but it is also possible to use an integrated electric compressor in which the compressor and the motor are coaxially connected.

[0058] In addition, in the above embodiment, the drive of the compressor 11 is switched between drive by the motor 16 and drive by the engine 4 depending on the amount of electricity stored in the second battery 17, but the present invention is not limited to this configuration and can also be applied to an arrangement in which the compressor is driven only by a battery and a motor.

[0059] Furthermore, in the above embodiment, the solenoid valves 27b, 27c, 27d, and 27e are opened and closed in conjunction with the operation and stoppage of the main pump 25 and the pump 27a to switch between the first and second flow modes. However, the first and second flow modes may also be switched by a manual switch that opens and closes the solenoid valves 27b, 27c, 27d, and 27e.

[0060] Furthermore, in the above embodiment, the power generating device 20 is used in the refrigerated vehicle 1, but the power generating device of the present invention can also be used in vehicles other than refrigerated vehicles, such as ships and aircraft.

[0061] 1...refrigerated vehicle, 2...vehicle body, 3...refrigerated storage compartment, 4...engine, 5...radiator, 6...first battery, 10...refrigeration device, 10a...refrigeration circuit, 11...compressor, 16...motor, 17...second battery, 20...power generation device, 21...evaporator, 22...expander, 23...condenser, 24...heat exchanger, 25...main pump, 25a...one-way valve, 25b...collector tank, 27...cooling water distribution circuit, 27a...pump, 27b, 27c, 27d, 27e...solenoid valves.

Claims

1. In a power generation device that uses an engine for driving a driven object and a radiator capable of exchanging heat between a heat medium for cooling the engine and the outside, an evaporator for evaporating a working fluid, an expander that rotates due to the expansion of the working fluid evaporated by the evaporator, a generator that generates electricity by the rotation of the expander, a condenser for condensing the working fluid flowing out of the expander, and a pump for circulating the working fluid flowing out of the condenser to the evaporator, and having a heat medium circulation circuit having switching means capable of switching between a first circulation mode in which the heat medium flowing out of the engine is circulated to the radiator and then flowed into the engine, and a second circulation mode in which the heat medium flowing out of the engine is circulated to the evaporator without passing through the radiator and then flowed into the engine, and the heat medium flowing out of the radiator is circulated to the condenser and then flowed into the radiator. A power generation device characterized by this.

2. The power generation device according to claim 1, wherein the heat medium circulation circuit switches between the first and second circulation modes by switching means so that the first heat medium circulation mode is adopted when power generation by the generator is not performed, and the second heat medium circulation mode is adopted when power generation by the generator is performed.

3. The power generation device according to claim 1, further comprising a heat exchanger for heat-exchanging the working fluid flowing out of the expander and the working fluid flowing out of the condenser.

4. In a refrigerated vehicle equipped with a vehicle engine, a radiator capable of exchanging heat between a heat medium for cooling the engine and the outside, a refrigeration circuit for cooling the inside of an in-vehicle cold storage, a motor for driving the compressor of the refrigeration circuit, and a battery for driving the motor, the power generation device according to any one of claims 1 to 3 for generating electric power to be stored in the battery is provided, and when the stored amount of the battery is equal to or more than a predetermined stored amount, the compressor is driven by the motor, and when the stored amount of the battery is less than the predetermined stored amount, the compressor is driven by the engine. A refrigerated vehicle characterized by this.

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