US20090031749A1

US20090031749A1 - Refrigeration apparatus with exhaust heat recovery device

Info

Publication number: US20090031749A1
Application number: US12/156,116
Authority: US
Inventors: Michio Nishikawa; Hironori Asa; Keiichi Uno; Hiroshi Kishita
Original assignee: Denso Corp; Nippon Soken Inc
Current assignee: Denso Corp; Soken Inc
Priority date: 2007-05-30
Filing date: 2008-05-28
Publication date: 2009-02-05
Also published as: JP2008297961A; DE102008025371A1

Abstract

A refrigeration apparatus with an exhaust heat recovery device mounted on a vehicle includes a refrigeration cycle for allowing a refrigerant for refrigeration to circulate therethrough, and a Rankine cycle for allowing a refrigerant for the Rankine cycle to circulate therethrough. The refrigeration-cycle condenser and the Rankine-cycle condenser are disposed in predetermined positions of the vehicle in series with respect to a flow direction of external air for cooling, and the refrigeration-cycle condenser is disposed on an upstream side of the external air with respect to the Rankine-cycle condenser.

Description

CROSS REFERENCE TO RELATED APPLICATION

This application is based on Japanese Patent Application No. 2007-144157 filed on May 30, 2007, the contents of which are incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates to a refrigeration apparatus with an exhaust heat recovery device for operating an expansion unit using exhaust heat from a vehicle, for example, an internal combustion engine, as a heating source.

BACKGROUND OF THE INVENTION

A conventional refrigeration apparatus with an exhaust heat recovery device is known in, for example, JP-A-2006-46763. The refrigeration apparatus includes a refrigeration cycle and a Rankine cycle using exhaust heat in cooling of an internal combustion engine serving as a heat generator. A compressor for compressing and discharging refrigerant in the refrigeration cycle and an expansion unit adapted to be operated in the Rankine cycle by expansion of refrigerant heated by the exhaust heat in cooling of the internal combustion engine are respectively independently located. A condenser (radiator) in the Rankine cycle is also used and configured as a condenser for the refrigeration cycle.
Such a refrigeration apparatus permits independent operation of the refrigeration cycle or the Rankine cycle, or the simultaneous operation of both the refrigeration cycle and the Rankine cycle according to the necessity of cooling operation for a vehicle compartment and the possibility of recovery of the exhaust heat in cooling.
In the above-mentioned refrigeration apparatus, however, when the refrigeration cycle and the Rankine cycle are simultaneously driven, the condenser condenses the refrigerant in both the cycles (i.e., radiates heat from both the cycles) at the same time, resulting in an increase in pressure of the refrigerant at the condenser. This leads to an increase in power of the compressor in the refrigeration cycle, thus resulting in reduction of reliability on the compressor, and also a decrease in coefficient of performance of the refrigeration cycle.
Further, the single operation of only the Rankine cycle may cause a difference in pressure between the condenser and the evaporator in accordance with an increase in pressure of the refrigerant at the condenser even though the refrigeration cycle is stopped, thereby allowing the refrigerant to be collected in the refrigeration cycle side (evaporator side). This may result in a decrease in amount of the refrigerant on the Rankine cycle side, so that an inherent capability of the Rankine cycle cannot be sufficiently exhibited. Moreover, because lubricating oil contained in the refrigerant may also be collected in the refrigeration cycle, shortage of lubrication of the expansion unit or a refrigerant pump may be caused, thus resulting in reduction of reliability on the expansion unit and refrigerant pump.

SUMMARY OF THE INVENTION

The invention has been made in view of the foregoing problems, and it is an object of the invention to provide a refrigeration apparatus with an exhaust heat recovery device, which includes a refrigeration cycle and a Rankine cycle and which can exhibit sufficient performance to both the cycles while ensuring reliability thereon.
According to an aspect of the present invention, a refrigeration apparatus with an exhaust heat recovery device mounted on a vehicle includes: a refrigeration cycle for allowing a refrigerant for refrigeration to circulate therethrough; and a Rankine cycle for allowing a refrigerant for the Rankine cycle to circulate therethrough. The refrigeration cycle includes a compressor, a refrigeration-cycle condenser, an expansion valve, and an evaporator which are connected in a circular shape. The Rankine cycle includes a pump, a heater using exhaust heat from a heat engine of the vehicle as a heating source, an expansion unit, and a Rankine-cycle condenser which are connected in a circular shape. In the refrigeration apparatus, the refrigeration-cycle condenser and the Rankine-cycle condenser are disposed in predetermined positions of the vehicle in series with respect to a flow direction of external air for cooling, and the refrigeration-cycle condenser is disposed on an upstream side of the external air with respect to the Rankine-cycle condenser.
Accordingly, regardless of the presence or absence of the operation of the Rankine cycle, the refrigeration-cycle condenser constantly allows an external fluid whose temperature is equal to the temperature of outside air to flow thereinto. In operation of the refrigeration cycle, it does not lead to reduction in reliability on the refrigeration cycle together with deterioration of power of the compressor, as well as a decrease in refrigeration capacity due to a decrease in coefficient of performance.
Further, in single operation of the Rankine cycle, each cycle constructs a corresponding independent refrigerant circuit, and thus the refrigerant and lubricating oil are not collected from the Rankine cycle into the refrigeration cycle. Accordingly, it can sufficiently exhibit the inherent capacity of the Rankine cycle, and ensure the reliability on the expansion unit and the pump. Thus, the refrigeration apparatus with the exhaust heat recovery device can exhibit sufficient performance to both the cycles, while ensuring the reliability thereon.
For example, the refrigeration apparatus may be provided with a control means for controlling operations of the refrigeration cycle and the Rankine cycle. In this case, the control means controls number of revolutions of the expansion unit such that an expansion-unit pressure difference in the expansion unit of the refrigerant for the Rankine cycle is equal to or more than a predetermined value, when both the refrigeration cycle and the Rankine cycle are simultaneously operated. Accordingly, even in the simultaneously operating of the refrigeration cycle and the Rankine cycle, it is possible to ensure a sufficient pressure difference of the expansion unit so as to obtain a sufficient regenerative power by the expansion unit, while preventing an unstable operation of the Rankine cycle.
Furthermore, the control means decreases the number of revolutions of the expansion unit when the expansion-unit pressure difference is smaller than the predetermined value. Accordingly, it is possible to accurately set the expansion-unit pressure difference to be equal to or larger than the predetermined value.
The control means controls the number of revolutions of the expansion unit such that the expansion-unit pressure difference has such a value as to obtain a predetermined appropriate expansion ratio in the expansion unit. This can appropriately expand and operate the expansion unit, thereby effectively regenerating the power by the expansion unit.
The refrigeration apparatus may be further provided with a high-pressure side pressure detection means located in a high-pressure side area leading from a downstream side of the pump to an upstream side of the expansion unit, and a low-pressure side pressure detection means located in a low-pressure side area leading from a downstream side of the expansion unit to an upstream side of the pump. The high-pressure side pressure detection means is adapted to detect a high-pressure side pressure of the refrigerant for the Rankine cycle, and the low-pressure side pressure detection means is adapted to detect a low-pressure side pressure of the refrigerant for the Rankine cycle. In this case, the control means may control the number of revolutions of the expansion unit based on a difference between the high-pressure side pressure and the low-pressure side pressure. Here, the difference indicates the expansion-unit pressure difference.
Alternatively, the refrigeration apparatus may be provided with a high-pressure side pressure detection means located in a high-pressure side area leading from a downstream side of the pump to an upstream side of the expansion unit, an air temperature detection means disposed between the refrigeration-cycle condenser and the Rankine-cycle condenser, and a calculation means. The high-pressure side pressure detection means is adapted to detect a high-pressure side pressure of the refrigerant for the Rankine cycle, and the air temperature detection means is adapted to detect an air temperature of the external air passing through between the refrigeration-cycle condenser and the Rankine-cycle condenser. The control means is adapted to calculate a temperature of the refrigerant for the Rankine cycle in the Rankine-cycle condenser, and further a low-pressure side pressure based on an amount of heat radiated at the Rankine-cycle condenser which is balanced with an amount of heat absorbed into the heater by exhaust heat, an amount of the external air passing through the Rankine-cycle condenser, and the air temperature detected by the air temperature detection means. In this case, the control means may control the number of revolutions of the expansion unit based on a difference, indicative of the expansion-unit pressure difference, between the high-pressure side pressure and the low-pressure side pressure.
Accordingly, it is possible to calculate (estimate) the expansion-unit pressure difference using the low-pressure side pressure detection means instead of the air temperature detection means, and also using the calculation means.
Alternatively, the refrigeration apparatus may be provided with: a high-pressure side pressure detection means located in a high-pressure side area leading from a downstream side of the pump to an upstream side of the expansion unit, to detect a high-pressure side pressure of the refrigerant for the Rankine cycle; an inflow air temperature detection means for detecting an inflow air temperature of the external air before flowing into the refrigeration-cycle condenser and the Rankine-cycle condenser; and calculation means for calculating a temperature of the external air after passing through the refrigeration-cycle condenser based on an amount of heat radiated at the refrigeration radiator which is balanced with a necessary refrigeration capacity at the evaporator, an amount of the external air passing through the refrigeration-cycle condenser, and the inflow air temperature detected by the inflow air temperature detection means. The calculation means is also adapted to calculate a temperature of the refrigerant for the Rankine cycle in the Rankine-cycle condenser, and further calculating a low-pressure side pressure based on an amount of heat radiated at the Rankine-cycle condenser which is balanced with an amount of heat absorbed into the heater by the exhaust heat, an amount of the external air passing through the Rankine-cycle condenser, and the calculated temperature of the external air after passing through the refrigeration-cycle condenser. In this case, the control means may control the number of revolutions of the expansion unit based on a difference, indicative of the expansion-unit pressure difference, between the high-pressure side pressure and the low-pressure side pressure.
In the refrigeration apparatus, positions of an inlet and an outlet of the refrigerant in the refrigeration-cycle condenser may be set in the same area as those of an inlet and an outlet of the refrigerant for the Rankine cycle in the Rankine-cycle condenser as viewed from the flow direction of the external air.
Thus, an inflow area and an outflow area of the refrigerant for refrigeration in the refrigeration-cycle condenser can have the same positional relationship as that of an inflow area and an outflow area of the refrigerant for the Rankine cycle in the Rankine-cycle condenser. The amount of increase in temperature of the external air having passed through the refrigeration-cycle condenser is high on the inflow side of the refrigerant for refrigeration, and becomes lower toward the outflow side. It is apparent that the temperature of the refrigerant for the Rankine cycle in the Rankine-cycle condenser becomes lower from the inflow side toward the outflow side by heat exchange. This can provide such a positional relationship that temperature distribution of the external air flowing into the Rankine-cycle condenser has the same tendency as that of the refrigerant for the Rankine cycle into the Rankine-cycle condenser. Thus, a difference in temperature between the external air and the refrigerant for the Rankine cycle can be entirely made uniform, which can effectively radiate heat from the Rankine-cycle condenser.
Alternatively, the refrigeration apparatus may be further provided with: an air-introduction flow path portion for allowing the external air to be introduced into the Rankine-cycle condenser from an upstream side of the external air of the refrigeration-cycle condenser through a space between the refrigeration-cycle condenser and the Rankine-cycle condenser; and an opening adjustment portion for adjusting an area of an opening toward the refrigeration-cycle condenser and an area of an opening toward the air-introduction flow path portion by being moved under control of the control means.
Thus, the amount of external air flowing into each condenser can be adjusted according to the necessary amount of heat radiated from each of the condensers for the refrigeration cycle and the Rankine cycle, so as to enable effective heat radiation at the respective condensers.
Furthermore, an area of a front surface of the refrigeration-cycle condenser may be made to be smaller than that of a front surface of the Rankine-cycle condenser, and the Rankine-cycle condenser may have an area at an upstream side of the external air where the refrigeration-cycle condenser is not superimposed. Thus, the external air whose temperature is equal to the outside air temperature and which is not subjected to the heat exchange at the refrigeration-cycle condenser can flow directly into the Rankine-cycle condenser, so that the radiation capacity of the radiator for the Rankine cycle can be improved.
Alternatively, a dimension of the refrigeration-cycle condenser in a flow direction of the external air may be set larger than that of the Rankine-cycle condenser. Accordingly, it is possible to obtain a higher heat radiation capacity of the refrigeration-cycle condenser by increasing a dimension of the external air in the direction of flow, and easily decrease an area of the front surface of the refrigeration-cycle condenser.
Alternatively, the inlet and the outlet of the refrigerant for refrigeration in the refrigeration-cycle condenser may be provided to be opened toward an upstream side in a flow direction of the external air. Thus, it is not necessary to dispose piping between the refrigeration-cycle condenser and the Rankine-cycle condenser in routing piping for refrigerant in the refrigeration-cycle condenser. This does not degrade the dimensional accuracy between both the condensers, and enables easy connection of the piping to the refrigeration-cycle condenser.
Furthermore, the inlet and the outlet of the refrigerant for the Rankine cycle in the Rankine-cycle condenser may be provided to be opened in a direction perpendicular to a flow direction of the external air.

BRIEF DESCRIPTION OF THE DRAWINGS

Additional objects and advantages of the present invention will be more readily apparent from the following detailed description of preferred embodiments when taken together with the accompanying drawings. In which:

FIG. 1 is a schematic diagram showing an entire system of a refrigeration apparatus with an exhaust heat recovery device according to a first embodiment of the invention;

FIG. 2 is a side view showing a mounting state of a refrigeration-cycle condenser, a Rankine-cycle condenser, and a radiator on a vehicle in the first embodiment;

FIG. 3 is a perspective view showing an inlet and an outlet for refrigerant of each of the refrigeration-cycle condenser and the Rankine-cycle condenser in the first embodiment;

FIG. 4 is a perspective view showing connection directions of piping with the inlets and outlets for refrigerant and for coolant in each of the refrigeration-cycle condenser, the Rankine-cycle condenser, and the radiator in the first embodiment;

FIG. 5 is a control characteristic diagram showing an operation mode of an electric fan with respect to a refrigerant pressure in the first embodiment;

FIG. 6 is a flowchart showing a control method for simultaneously operating the refrigeration cycle and the Rankine cycle in the first embodiment;

FIG. 7 is a schematic diagram showing an entire system of a refrigeration apparatus with an exhaust heat recovery device according to a second embodiment of the invention;

FIG. 8 is a flowchart showing a control method for simultaneously operating the refrigeration cycle and the Rankine cycle in the second embodiment;

FIG. 9 is a schematic diagram showing an entire system of a refrigeration apparatus with an exhaust heat recovery device according to a third embodiment of the invention;

FIG. 10 is a flowchart showing a control method for simultaneously operating the refrigeration cycle and the Rankine cycle in the third embodiment;

FIG. 11 is a plan view showing a duct and a guide in a fourth embodiment of the invention;

FIG. 12 is a perspective view showing a refrigeration-cycle condenser and a Rankine-cycle condenser in a fifth embodiment of the invention; and

FIG. 13 is a perspective view for supplemental explanation showing the refrigeration-cycle condenser and the Rankine-cycle condenser in the fifth embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

First Embodiment

A first embodiment of the invention is shown in FIGS. 1 to 6. First, the specific structure of the first embodiment will be described below. FIG. 1 is a schematic diagram showing an entire system of a refrigeration apparatus 100A with an exhaust heat recovery device (hereinafter referred to as a “refrigeration apparatus”). FIG. 2 is a side view showing a mounting state of a refrigeration-cycle condenser 220 (hereinafter referred to as an “AC condenser”), a Rankine-cycle condenser 340 (hereinafter referred to as an “RA condenser”), and a radiator 21 on a vehicle. FIG. 3 is a perspective view showing inlets 220 a and 340 a and outlets 220 b and 340 b for refrigerant of the AC condenser 220 and the RA condenser 340. FIG. 4 is a perspective view showing connection directions of piping with the inlets 220 a, 340 a, and 21 a, and the outlets 220 b, 340 b, and 21 b for refrigerant and coolant of the AC condenser 220, the RA condenser 340, and the radiator 21. FIG. 5 is a control characteristic diagram showing operation modes of an electric fan 260 with respect to refrigerant pressures. FIG. 6 is a flowchart 1 showing a control method for simultaneously operating a refrigeration cycle 200 and a Rankine cycle 300.
As shown in FIG. 1, the refrigeration apparatus 100A of the first embodiment is applied to a vehicle using an engine 10 as a driving source. The refrigeration apparatus 100A is provided with the refrigeration cycle 200 and the Rankine cycle 300. The operations of the respective cycles 200 and 300 are controlled by an energization control circuit 50.
The engine 10 is a water-cooled internal combustion engine (corresponding to a heat engine in the invention), and is provided with a radiator circuit 20 for cooling the engine 10 by circulation of engine coolant, and a heater circuit 30 for heating conditioned air (i.e., air to be conditioned) using the coolant (warm water) as a heating source.
The radiator circuit 20 is provided with the radiator 21, which cools the coolant circulating by a warm water pump 22, by performing heat exchange with outside air. The warm pump 22 may be either an electric pump or a mechanical pump. A heater 320 in the Rankine cycle 300 to be described later is disposed in a flow path on the outlet side of the engine (in a flow path between the engine 10 and the radiator 21), so that the coolant flows through the heater 320. A radiator bypass flow path 23 for bypassing the radiator 21 and for allowing the coolant to flow therethrough is provided in the radiator circuit 20. A thermostat 24 adjusts an amount of coolant flowing through the radiator 21 and an amount of coolant flowing through the radiator bypass flow path 23.
The heater circuit 30 is provided with a heater core 31, and allows the coolant (warm water) to circulate therethrough by the above-mentioned warm water pump 22. The heater core 31 is disposed in an air conditioning case 410 of an air conditioning unit 400, and heats the conditioned air blown by the blower 420 by heat exchange with the warm water. The heater core 31 is provided with an air mix door 430. The air mix door 430 is opened or closed to adjust the amount of conditioned air flowing through the heater core 31.
The refrigeration cycle 200 includes a compressor 210, an AC condenser 220, a liquid receiver 230, an expansion valve 240, and an evaporator 250, which are connected in an annular shape to form a closed circuit. The compressor 210 is a fluid device for compressing refrigerant in the refrigeration cycle 200 at a high temperature and a high pressure (here, the refrigerant corresponds to refrigerant for refrigeration in the invention, and which is hereinafter referred to as an “AC refrigerant”). The compressor 210 is driven by a driving force of the engine 10. That is, a pulley 211 serving as driving means is fixed to a driving shaft of the compressor 210, so that the driving force of the engine 10 is transferred to the pulley 211 via a belt 11 to drive the compressor 210. The pulley 211 is provided with an electromagnetic clutch not shown for intermittently connecting between the compressor 210 and the pulley 211. The intermittent connection of the electromagnetic clutch is controlled by the energization control circuit 50 to be described later. The AC refrigerant circulates through the refrigeration cycle 200 by operating the compressor 210.
The AC condenser 220 is connected to the discharge side of the compressor 210. The condenser 220 is a heat exchanger for condensing and liquifying the AC refrigerant flowing therethrough by heat exchange with cooling air (corresponding to external air in the invention). The liquid receiver 230 is a receiver for separating the AC refrigerant condensed by the AC condenser 220 into two liquid-gas phases, and allows the only liquefied AC refrigerant separated to flow out toward the expansion valve 240. The expansion valve 240 decompresses and expands the liquefied AC refrigerant from the liquid receiver 230. This embodiment employs a thermal expansion valve for isentropically decompressing the AC refrigerant, and for controlling an opening degree of a throttle such that a degree of superheat of the AC refrigerant drawn from the evaporator 250 into the compressor 210 has a predetermined value.
The evaporator 250 is disposed in the air conditioning case 410 of the air conditioning unit 400, like the heater core 31. The evaporator 250 is a heat exchanger for evaporating the AC refrigerant decompressed and expanded by the expansion valve 240, and for cooling the conditioned air from the blower 420 by latent heat of the evaporation at that time. The refrigerant outlet side of the evaporator 250 is connected to the suction side of the compressor 210. A mixture ratio of air cooled by the evaporator 250 to air heated by the heater core 31 is changed according to the opening degree of the air mix door 430, so that the temperature of the conditioned air is adjusted to a certain temperature set by a passenger.
In contrast, the Rankine cycle 300 is adapted to recover exhaust heat energy generated by the engine 10 (heat from the coolant), and to convert the exhaust heat energy into mechanical energy (a driving force of the expansion unit 330), and further into electric energy (electric power generated by an electric generator 331) in use. The Rankine cycle 300 will be described below.
The Rankine cycle 300 includes a pump 310, a heater 320, an expansion unit 330, a condenser 340, and a liquid receiver 350, which are connected in an annular shape to form a closed circuit.
The pump 310 is an electric pump for allowing the refrigerant in the Rankine cycle 300 to circulate therethrough (which corresponds to refrigerant for the Rankine cycle in the invention, and which is hereinafter referred to as an “RA refrigerant”) using an electric motor 311 as a driving source. The electric motor 311 is operated by the energization control circuit 50 to be described later. The RA refrigerant is the same refrigerant as the above-mentioned AC refrigerant. The heater 320 is a heat exchanger for heating the RA refrigerant by heat exchange between the RA refrigerant fed from the pump 310 and the high-temperature coolant circulating through the radiator circuit 20.
The expansion unit 330 is a fluid device for generating a rotation driving force by expansion of the superheated-steam RA refrigerant heated by the heater 320. The electric generator 331 is connected to a driving shaft of the expansion unit 330. The electric generator 331 is operated by the driving force of the expansion unit 330 as will be described later, so that electric power generated by the electric generator 331 is charged into a battery 40 via an inverter 51 included in the energization control circuit 50 to be described later. The RA refrigerant flowing from the expansion unit 330 leads to the RA condenser 340.
The RA condenser 340 is connected to the discharge side of the expansion unit 330. The condenser 340 is a heat exchanger for condensing and liquifying the RA refrigerant flowing therethrough by heat exchange with cooling air (corresponding to external air in the invention). The liquid receiver 350 is a receiver for separating the RA refrigerant condensed by the RA condenser 340 into two liquid-gas phases, and allows only the separated liquid RA refrigerant to flow out toward the pump 310.
A pressure sensor (corresponding to high-pressure side pressure detection means in the invention) 301 for detecting a pressure of the RA refrigerant (a high-pressure side pressure PHr) is provided at a high-pressure side area leading from the discharge side (downstream side) of the pump 310 of the Rankine cycle 300 to the inflow side (upstream side) of the expansion unit 330. The pressure sensor 301 is disposed between the heater 320 and the expansion unit 330 in the high-pressure side area. Another pressure sensor (corresponding to low-pressure side pressure detection means in the invention) 302 for detecting a pressure of the RA refrigerant (a low-pressure side pressure PLr) is provided at a low-pressure side area leading from the discharge side (downstream side) of the expansion unit 330 to the suction side (upstream side) of the pump 310. The pressure sensor 302 is disposed between the expansion unit 330 and the RA condenser 340 in the low-pressure side area. Pressure signals detected by both the pressure sensors 301 and 302 are output to the energization control circuit 50 to be described later.
As shown in FIG. 2, the AC condenser 220 in the refrigeration cycle 200, the RA condenser 340 in the Rankine cycle 300, and the radiator 21 in the radiator circuit 20 are arranged on the rear side of a vehicle grill, that is, on the front side of an engine room. In running of the vehicle, the cooling air (external air) flows from the vehicle grill into the engine room. The AC condenser 220, the RA condenser 340, and the radiator 21 are arranged in series in that order from the upstream side to the downstream side with respect to the flow direction of the cooling air and mounted on the vehicle. The upstream side of the flow direction of the cooling air will be referred to as a “front side” and the downstream side as a “rear side” with respect to a position in the front/back direction of the vehicle.
As shown in FIG. 3, the inlet 220 a and the outlet 220 b for the AC refrigerant are provided on one end side in the horizontal direction of the AC condenser 220 (on the right side in mounting of the condenser on the vehicle). The inlet 220 a is disposed on the upper side (on the upper right side in mounting), and the outlet 220 b on the lower side (on the lower right side in mounting). The inlet 340 a and the outlet 340 b of the RA refrigerant with respect to the RA condenser 340 are positioned in the same respective areas as those of the inlet 220 a and the outlet 220 b with respect to the AC condenser 220. That is, the positions of the inlet 220 a of the AC condenser 220 and of the inlet 340 a of the RA condenser 340 are positioned on the upper right side in mounting of the condensers on the vehicle. The positions of the outlet 220 b of the AC condenser 220 and of the outlet 340 b of the RA condenser 340 are positioned on the lower right side in mounting.
Further, as shown in FIG. 4, the inlet 220 a and the outlet 220 b of the AC condenser 220 are opened to the forward side (the grill side), and the refrigerant piping is connected from the front side to the rear side. The inlet 340 a and the outlet 340 b of the RA condenser 340 are opened in the direction perpendicular to the flow direction of the cooling air (to the right side in the width direction of the vehicle), and the refrigerant piping is connected from the right side to the left side in the width direction. The inlet 21 a and the outlet 21 b of the coolant of the radiator 21 are opened toward the rear side (toward the engine 10 side), and the coolant piping is connected from the rear side to the front side.
An electric fan 260 in which an axial blower fan is rotatably driven by an electric motor serving as a driving source is provided on the rear side of the radiator 21 among the AC condenser 220, the RA condenser 340, and the radiator 21 arranged in series in the engine room (see FIG. 1). The electric fan 260 is the so-called suction-type blowing means for forcedly supplying the cooling air to the AC condenser 220, the RA condenser 340, and the radiator 21 from the front side to the rear side by rotatably driving the fan. When the sufficient amount of inflow of the cooling air is not expected from the vehicle grill (in idling, in climbing a slope at low speeds, or the like), and also when radiation capacities of the AC condenser 220, the RA condenser 340, and the radiator 21 cannot be derived sufficiently, the electric fan 260 is operated to promote the supply of the cooling air.
Specifically, as shown in FIG. 5, the operation of the electric fan 260 is controlled by the energization control circuit 50 to be described later. When a high-pressure side AC refrigerant pressure of the refrigeration cycle 200 is equal to or less than α (or when a temperature of coolant is equal to or less than a predetermined temperature), the electric fan 260 is operated in a Low mode (Lo mode). Further, when a high-pressure side AC refrigerant pressure is equal to or more than α+β (or when a temperature of coolant is equal to or more than a predetermined temperature+γ), the electric fan 260 is operated in a High mode (Hi mode).
The energization control circuit 50 is control means for controlling the operations of various devices in the above-mentioned refrigeration cycle 200 and the Rankine cycle 300, and includes the inverter 51 and a controller 52.
The inverter 51 is to control the operation of the electric generator 331 connected to the expansion unit 330. When the electric generator 331 is operated by the driving force of the expansion valve 330, the inverter 51 charges the generated power into the battery 40.
The controller 52 controls the operation of the inverter 51. Also, the controller 52 controls the electromagnetic clutch, the electric fan 260, the electric motor 311 of the pump 310, and the like by obtaining detection signals from the pressure sensors 301 and 302 in operating the refrigeration cycle 200 and the Rankine cycle 300.
Now, the operations and effects of this arrangement will be described below.
1. Single Operation of Refrigeration Cycle
When a request for air conditioning is made while no exhaust heat is obtained during warming or the like directly after the startup of the engine 10, the energization control circuit 50 stops the electric motor 311 of the pump 310 (while stopping the expansion unit 320), engages the electromagnetic clutch, drives the compressor 210 by the driving force of the engine 10, and singly drives the refrigeration cycle 200. In this case, the refrigeration cycle 200 operates in the same way as a normal air conditioner for a vehicle.
2. Single Operation of Rankine Cycle
When the sufficient exhaust heat is generated from the engine 10 without an requirement for air conditioning, the energization control circuit 50 disconnects the electromagnetic clutch (stops the compressor 210), operates the electric motor 311 (the pump 310), and singly operates the Rankine cycle 300 thereby to generate electricity.
In this case, the RA liquid refrigerant in the liquid receiver 350 has a pressure increased by the pump 310 to be fed to the heater 320. By the heater 320, the RA liquid refrigerant is heated by high-temperature engine coolant to become RA superheated steam refrigerant, which is fed to the expansion unit 330. The RA superheated steam refrigerant is isentropically expanded and decompressed by the expansion unit 330, and has part of thermal energy and pressure energy converted into a rotation driving force. The rotation driving force taken by the expansion unit 330 operates the electric generator 331, which then generates the electricity. The electric power generated by the electric generator 331 is charged into the buttery 40 via the inverter 51, and then used for operations of various auxiliary devices. The RA refrigerant decompressed by the expansion unit 330 is condensed by the RA condenser 340, separated into liquid and gas phases by the liquid receiver 350, and drawn again into the pump 310.
3. Simultaneous Operation of Refrigeration Cycle and Rankine Cycle
When exhaust heat is sufficiently generated with a requirement for air conditioning made, the energization control circuit 50 simultaneously drives and operates both the refrigeration cycle 200 and the Rankine cycle 300, thereby performing both of the air conditioning and the electricity generation.
In this case, the electromagnetic clutch is connected or engaged to operate the electric motor 311 (pump 310). The AC refrigerant and the RA refrigerant respectively circulate through the refrigeration cycle 200 and the Rankine cycle 300. The operation of each of the cycles 200 and 300 is the same as that in singly operating thereof.
Since the RA condenser 340 is disposed on the rear side of the AC condenser 220 in simultaneous operation of the above-mentioned refrigeration cycle and Rankine cycle, the cooling air having the outside air temperature flows into the AC condenser 220, and the cooling air whose temperature is increased by heat exchange at the AC condenser 220 flows into the RA condenser 340. Thus, the RA condenser 340 has a lower radiation capacity as compared to a case where the cooling air having the outside air temperature (external air not being affected by the heat exchange) purely flows into the RA condenser 340. Together with this, a low-pressure side pressure PLr of the Rankine cycle 300 is increased. The increase in low-pressure side pressure PLr decreases a pressure difference ΔP of the expansion unit of the RA refrigerant at the expansion unit 330, so that the driving force regenerated is reduced, resulting in a decrease in amount of electricity generated. Further, the operation of the Rankine cycle 300 becomes unstable. Thus, in order to suppress the decrease in amount of electricity generated and prevent the unstable operation of the Rankine cycle 300, the energization control circuit 50 performs control for preventing a decrease in pressure difference based on a control flowchart 1 shown in FIG. 6.
That is, when the refrigeration cycle and the Rankine cycle are simultaneously driven in step S100, first, the energization control circuit 50 reads in a high-pressure side pressure PHr and a low-pressure side pressure PLr detected by the pressure sensors 301 and 302 in step S110. In step S120, the low-pressure side pressure PLr is subtracted from the high-pressure side pressure PHr thereby to calculate a pressure difference ΔP of the expansion unit.
Then, in step S130, it is determined whether or not the expansion unit pressure difference ΔP calculated in the above-mentioned step S120 is smaller than a predetermined pressure difference ΔPa (corresponding to a predetermined value in the invention). The predetermined pressure difference ΔPa is defined as a lower limit of the pressure difference which allows overexpansion of the expansion unit 330, while enabling the stable operation of the Rankine cycle 300.
For example, when the expansion unit 330 of this embodiment is intended to be appropriately expanded at the high-pressure side pressure PHr=2.3 MPa and at the expansion ratio=2.0, it is necessary to set the low-pressure side pressure PLr at 1.15 MPa, and the appropriate expansion unit pressure difference ΔPo for the appropriate expansion at 1.15 MPa. When the expansion unit pressure difference ΔP is smaller than the appropriate expansion unit pressure difference ΔPo, the expansion unit 330 is over-expanded. As the expansion unit pressure difference ΔP is decreased, the operation of the Rankine cycle 300 becomes more unstable. When the expansion unit pressure difference ΔP is larger than an appropriate expansion unit pressure difference ΔPo, the expansion of the expansion unit 330 is insufficient. Thus, the minimum expansion unit pressure difference ΔP without an unstable operation of the Rankine cycle 300 is set as the predetermined pressure difference ΔPa. Under the above-mentioned condition, for example, the predetermined pressure difference ΔPa is set to 0.8 Mpa (ΔPa=0.8 Mpa) (which corresponds to 70% level of the appropriate expansion unit pressure difference ΔPo).
When the expansion unit pressure difference ΔP is determined to be smaller than the predetermined pressure difference ΔPa in step S130, it is determined whether or not the number of revolutions of the present expansion unit 330 is the minimum operable number of revolutions in step S140. The number of revolutions of the expansion unit which is equal to the number of revolutions of the electric generator 331 is detected by the inverter 51.
When the number of revolutions of the expansion unit is determined not to be the minimum number of revolutions in step S140, the number of revolutions of the expansion unit 330 can be decreased, and the energization control circuit 50 decreases the number of revolutions of the expansion unit 330 only by a predetermined amount. In decreasing the number of revolutions of the expansion unit 330, electric current is supplied from the inverter 51 to the electric generator 331 during generation of electricity to provide a braking effect.
When the number of revolutions of the expansion unit is decreased in step S150, a resistance effect to the RA refrigerant in the expansion unit 330 is enhanced to decrease a low-pressure side pressure PLr, thereby increasing the expansion unit pressure difference ΔP. Thus, by repeating of the above-mentioned steps S110 to 150, the expansion unit pressure difference ΔP is controlled such that the pressure difference ΔP is equal to or more than the predetermined pressure difference ΔPa.
If the determination of step S140 is NO, that is, when the number of revolutions of the expansion unit is determined to be already the minimum number of revolutions in step S140, the expansion unit pressure difference ΔP cannot be controlled so as to be equal to or more than the predetermined pressure difference ΔPa as mentioned above. In this case, the Rankine cycle 300 is stopped for the purpose of safety in step S160. If the determination of step S130 is NO, that is, when the expansion unit pressure difference ΔP is determined to be larger than the predetermined pressure difference ΔPa, the control of the number of revolutions of the expansion unit 330 is unnecessary, and the operation returns to a step S100.
As mentioned above, in this embodiment, the AC condenser 220 and the RA condenser 340 dedicated are respectively set in the refrigeration cycle 200 and the Rankine cycle 300, and the AC condenser 220 is disposed on the front side of the RA condenser 340 (on the upstream side of the flow of the cooling air). Thus, regardless of the presence or absence of the operation of the Rankine cycle 300, the AC condenser 220 constantly allows an external fluid whose temperature is equal to the temperature of outside air to flow thereinto. In operation of the refrigeration cycle 200, this does not lead to reduction in reliability on the refrigeration cycle 200 together with deterioration of power of the compressor 210, as well as a decrease in refrigeration capacity together with a decrease in coefficient of performance.
In singly operating of the Rankine cycle 300, the respective cycles 200 and 300 form the independent refrigerant circuits, so that the Rankine cycle 300 can exhibit a sufficient inherent capacity, while ensuring reliability of the expansion unit 330 and the pump 310 without storing the refrigerant and lubricating oil from the Rankine cycle 300 into the refrigeration cycle 200.
This can ensure the reliability of both the Rankine cycles 200 and 300, and provide the refrigeration apparatus 100A that can exhibit the sufficient performance as a whole.
In the simultaneous operation of the refrigeration cycle 200 and the Rankine cycle 300, the number of revolutions of the expansion unit 330 is decreased such that the expansion unit pressure difference ΔP is equal to or more than the predetermined pressure difference ΔPa. This can ensure the sufficient expansion unit pressure difference ΔP to prevent the unstable operation of the Rankine cycle 300, while obtain the sufficient amount of electricity generated by the expansion unit 330.
The calculation of the expansion unit pressure difference ΔP can be performed easily and surely by use of pressure values detected by two pressure sensors 301 and 302.
The positions of the inlet 220 a and outlet 220 b of the AC condenser 220 are positioned in the same respective areas as those of the inlet 340 a and outlet 340 b of the RA condenser 340 as viewed from the flow direction of the cooling air. Thus, the inflow area and outflow area for the AC refrigerant in the AC condenser 220 can have the same positional relationship as that of the inflow area and outflow area for the RA refrigerant in the RA condenser 340. The amount of increase in temperature of cooling air passing through the AC condenser 220 is high on the inlet side of the AC refrigerant, and becomes lower toward the outflow side. It is apparent that the temperature of the RA refrigerant in the RA condenser 340 becomes lower from the inflow side toward the outflow side by the heat exchange. This can provide such a positional relationship that the temperature distribution of the cooling air flowing into the RA condenser 340 has the same tendency as that of the RA refrigerant into the RA condenser 340. Thus, the difference in temperature between the cooling air and the RA refrigerant can be entirely made uniform, and thereby it is possible to effectively radiate heat from the RA condenser 340.
The inlet 220 a and outlet 220 b of the AC condenser 220 are opened toward the front side. Thus, it is not necessary to dispose piping between the AC condenser 220 and the RA condenser 340 in routing piping for the AC refrigerant to the AC condenser 220. This does not degrade a dimensional accuracy between both condensers 220 and 340, and can facilitate connection of the piping to the AC condenser 220.
The inlet 340 a and outlet 340 b of the RA condenser 340 are opened in the direction perpendicular to the flow direction of the cooling air. Thus, it is not necessary to dispose piping between the AC condenser 220 and the RA condenser 340, or to dispose piping from the front side to the rear side in routing piping for the RA refrigerant to the RA condenser 340. Accordingly, it can prevent degradation of a dimensional accuracy between both the condensers 220 and 340, or a decrease in area of the front surface of the AC condenser 220. Further, this can also facilitate connection of the piping to the RA condenser 340.
In control of preventing a decrease in pressure difference based on a flowchart 1 shown in FIG. 6, after the number of revolutions of the expansion unit 330 is controlled such that the expansion unit pressure difference ΔP is equal to or more than the predetermined pressure difference ΔPa, the number of revolutions of the expansion unit 330 may be preferably controlled such that the expansion unit pressure difference ΔP becomes the appropriate pressure difference ΔPo. Thus, it can constantly obtain the optimal amount of electricity generated.

Second Embodiment

FIGS. 7 and 8 show a second embodiment of the invention. The second embodiment differs from the first embodiment in a method of calculating an expansion unit pressure difference ΔP.
A refrigeration apparatus 100B of the second embodiment has the same basic structure as that of the refrigeration apparatus 100A of the first embodiment. As shown in FIG. 7, the pressure sensor 302 is omitted, and the refrigeration apparatus 100B is provided with a temperature sensor (corresponding to an air temperature detection means in the invention) 101 for detecting the temperature of cooling air passing between the AC condenser 220 and the RA condenser 340 (a passing air temperature Tas). A temperature signal (passing air temperature Tas) detected by the temperature sensor 101 is output to the energization control circuit 50.
In a flowchart 2 for controlling prevention of a decrease in pressure difference, as shown in FIG. 8, steps S110 and S120 in the flowchart 1 shown in FIG. 6 and explained in the first embodiment are changed into steps S111 and S121, respectively, and a step S115 is added to between steps S111 and S121.
Now, the control of prevention of the decrease in pressure difference based on the flowchart 2 will be described below. That is, when the refrigeration cycle 200 and the Rankine cycle 300 are simultaneously driven and operated in step S100, the energization control circuit 50 reads a high-pressure side pressure PHr detected by the pressure sensor 301 and a passing air temperature Tas detected by the temperature sensor 101 in step S11.
In step S115, the low-pressure side pressure PLr is calculated. The outline of the calculation will be described below. The step S115 corresponds to calculation means for calculating the low-pressure side pressure PLr.
First, an amount of heat Qir absorbed by the heater 220 from the coolant is estimated. When Φh is a temperature efficiency of the heater 220, CW is a specific heat of the coolant, Gw is a flow rate by weight of the coolant, Tw is a temperature of the coolant, and THr is a temperature of the RA refrigerant at the heater 220, the following equation can be represented:
Qir=Φh·Cw·Gw·(Tw−THr)
Next, in the Rankine cycle 300, when Qor is an amount of heat radiation at the RA radiator 340 which is balanced with an amount of heat Qir absorbed at the heater 32, the following equation can be estimated:
Qor=A·Qir
wherein A is a coefficient corresponding to a driving force of the expender 330, for example, 0.9 (A=0.9).
Further, when Φcr is a temperature efficiency of the RA condenser 340, Ca is a specific heat of the cooling air, Ga is a flow rate by weight of the cooling air, TLr is a temperature of the RA refrigerant at the RA condenser 340, and Tas is a temperature of the cooling air flowing into the RA condenser 340, that is, a passing air temperature, the following equation can be represented:
Qor=Φcr·Ca·Ga·(TLr−Tas)
Accordingly, the following formula (1) can be obtained:
A·Φh·Cw·Gw·(Tw−THr)=Φcr·Ca·Ga·(TLr−Tas) (1)
The temperature efficiency Φh is determined according to set specifications of the heater 220. The coolant specific heat Cw is determined as a value of a physical property of the coolant. The flow rate by weight of the coolant Gw can be estimated from the number of revolutions of the warm water pump 22. The temperature of the coolant Tw can be determined using temperature data of the coolant associated with engine control. The RA refrigerant THr can be estimated from the high-pressure side pressure value (PHr) read in step S111.
The temperature efficiency Φr is determined according to set specifications of the RA condenser 340. The cooling air specific heat Ca is determined as a value of a physical property of the air. The flow rate by weight of the cooling air Ga can be estimated from the vehicle speed, and an operating state of the electric fan 260. As the passing air temperature Tas, a value read in step S111 is used.
Thus, the RA refrigerant temperature TLr can be calculated from the formula (1) and the above-mentioned condition. Further, a low-pressure side pressure PLr at the RA condenser 340 can be calculated from the thus-obtained RA refrigerant temperature TLr.
In step S121, an expansion unit pressure difference ΔP is calculated by subtracting the low-pressure side pressure PLr calculated in step S115 from the high-pressure side pressure PHr read in step S111.
As mentioned above, the execution of steps S130 to S160 can perform control for preventing a decrease in pressure difference, like the first embodiment, thereby obtaining the same effects as those of the first embodiment.
In the second embodiment, the low-pressure side pressure calculation means of step S115 is provided, so that the pressure sensor 302 can calculate the expansion unit pressure difference ΔP, instead of the temperature sensor 101.

Third Embodiment

FIGS. 9 and 10 show a third embodiment of the invention. The third embodiment differs from the first embodiment in a method of calculating an expansion unit pressure difference ΔP, like the second embodiment.
A refrigeration apparatus 100C of the third embodiment has the same basic structure as that of the refrigeration apparatus 100A of the first embodiment. As shown in FIG. 9, the pressure sensor 302 is omitted, and the refrigeration apparatus 100C is provided with a temperature sensor (corresponding to inflow air temperature detection means in the invention) 102 for detecting the temperature of cooling air flowing into the AC condenser 220 (inflow air temperature Ta). A temperature signal (inflow air temperature Ta) detected by the temperature sensor 102 is output to the energization control circuit 50.
In a flowchart 3 for controlling prevention of a decrease in pressure difference, as shown in FIG. 10, steps S110 and S120 in the flowchart 1 shown in FIG. 6 and explained in the first embodiment are changed into steps S112 and S122, respectively, and step S116 is added to between the steps S112 and S122.
Now, the control of prevention of the decrease in pressure difference based on the flowchart 3 will be described below. That is, when the refrigeration cycle and the Rankine cycle are simultaneously driven in step S100, the energization control circuit 50 reads a high-pressure side pressure PHr detected by the pressure sensor 301 and an inflow air temperature Ta detected by the temperature sensor 102 in step S112.
In step S116, a low-pressure side pressure PLr is calculated. The outline of the calculation will be described below. Step S116 corresponds to calculation means for calculating the low-pressure side pressure PLr.
In the refrigeration cycle 200, first, when Qoa is a necessary refrigeration capacity, that is, an amount of heat radiation at the AC condenser 220 which is balanced with an amount of heat absorbed Qia at the evaporator 250, the following equation can be estimated:
B·Qoa=Qia
wherein B is a coefficient corresponding to a driving force of the compressor 210, for example, 0.7 (B=0.7).
Further, when Φca is a temperature efficiency of the AC condenser 220, Ca is a specific heat of the cooling air, Ga is a flow rate by weight of the cooling air, Tas is a passing air temperature of the cooling air after passing through the AC condenser 220, and Ta is a temperature of the air flowing into the AC condenser 220, the following equation can be represented:
Qoa=Φca·Ca·Ga·(Tas−Ta)
Accordingly, the following formula (2) can be obtained:
B·Φca·Ca·Ga·(Tas−Ta)=Φia (2)
The temperature efficiency Φca is determined according to set specifications of the AC condenser 220. The coolant specific heat Ca is determined as a value of a physical property of the air. The flow rate by weight of the cooling air Ga can be estimated from a vehicle speed and an operating state of the electric fan 260. As the inflow air temperature Ta, a value read in step S112 is used. The amount of absorbed heat Qia is calculated from an environmental condition and a set temperature set by a passenger.
Thus, the passing air temperature Tas can be calculated from the formula (2) and the above-mentioned condition.
Using the passing air temperature Tas calculated above, the same computation as that in step S115 of the second embodiment can be performed to calculate the low-pressure side pressure PLr.
Then, in step S122, the expansion unit pressure difference ΔP is calculated by subtracting the low-pressure side pressure PLr calculated in step S116 from the high-pressure side pressure PHr read in step S112.
As mentioned above, the execution of steps S130 to S160 can perform control for preventing a decrease in pressure difference, like the first embodiment, thereby obtaining the same effects as those of the first embodiment.
In the third embodiment, the low-pressure side pressure calculation means of step S116 is provided, so that the pressure sensor 302 can calculate the expansion unit pressure difference ΔP, instead of the temperature sensor 102.

Fourth Embodiment

FIG. 11 shows a fourth embodiment of the invention. In the fourth embodiment, ducts 103 serving as an introduction flow path, and guides 104 serving as an opening adjustment portion are provided relative to the AC condenser 220 and the RA condenser 340 of the first to third embodiments.
The ducts 103 each of which is a plate-like member adapted for introduction of air are provided on both ends of the RA condenser 340 in the vehicle width direction. The ducts 103 are formed so as to expand from both ends of the RA condenser 340 to the front side of the AC condenser 220. As indicated by the dashed arrow in FIG. 11, the ducts 103 are formed so as to allow cooling air to be directly introduced into the RA condenser 340 through between the AC condenser 220 and the RA condenser 340 on both ends without allowing the cooling air to pass from the front side of the AC condenser 220 through the AC condenser 220.
The guides 104 each of which is formed as a plate-like member are disposed on both ends of the AC condenser 220 in the vehicle width direction and adapted to be rotatably operated around the respective ends in the vehicle width direction by the energization control circuit 50. As indicated by the solid arrow in FIG. 11, when the guide 104 is rotated toward the outside in the vehicle width direction, an area of an opening to the AC condenser 220 is enlarged to increase an amount of inflow of the cooling air into the AC condenser 220. In contrast, as indicated by the dashed arrow in FIG. 11, when the guide 104 is rotated toward the inside in the vehicle width direction, an area of opening in a flow path formed by the duct 103, that is, a flow path directed toward between the AC condenser 220 and the RA condenser 340 is enlarged to increase an amount of inflow of the cooling air into the RA condenser 340.
In the fourth embodiment thus obtained, the position of rotation of the guide 104 is controlled by the energization control circuit 50 according to a necessary amount of heat radiated from each of the AC condenser 220 and the RA condenser 340. In other words, in singly operating of the refrigeration cycle 200, the guides 104 are controlled to be rotated according to the necessary amount of heat radiated from the AC condenser 220. The rotating of the guide 104 toward the outside in the vehicle width direction increases an amount of inflow of the cooling air into the AC condenser 220, thereby enabling improvement of heat radiation characteristics of the AC condenser 220. At this time, the guide 104 can prevent the cooling air having passed through the AC condenser 220 from flowing again into the AC condenser 220.
In singly operating of the Rankine cycle, the guides 104 are controlled to be rotated according to the necessary amount of heat radiated from the RA condenser 340. The rotating of the guide 104 toward the inside in the vehicle width direction increases an amount of inflow of the cooling air into the RA condenser 340 without receiving resistance of the AC condenser 220, thereby enabling improvement of heat radiation performance of the RA condenser 340.
Furthermore, in simultaneously operating the refrigeration cycle and the Rankine cycle, the guides 104 are controlled to be rotated according to the necessary amount of heat radiated from both condensers 220 and 340. In this case, the guides 104 are rotated toward the inside in the vehicle width direction, thus allowing the cooling air whose temperature is the same as that of the outside air to flow into the RA condenser 340, thereby improving the heat radiation performance at the RA condenser 340.
In this way, the amounts of inflow of the cooling air into the condensers 220 and 340 are adjusted according to the respective necessary amounts of heat radiated from the AC condenser 220 and the RA condenser 340, thereby enabling effective heat radiation at each of the condensers 220 and 340.

Fifth Embodiment

FIGS. 12 and 13 show a fifth embodiment of the invention. In the fifth embodiment, an area of a front surface of the AC condenser 220 is set to be smaller than that of a front surface of the RA condenser 340 so as to form an area (e.g., an A area shown in FIGS. 12 and 13) where both condensers 220 and 340 are not overlapped with each other.
The dimension in the vertical direction of the AC condenser 220 is smaller than that of the RA condenser 340, which forms the area where both condensers 220 and 340 are not superimposed on each other on the lower side of the AC condenser 220.
If the dimension in the vertical direction of the AC condenser 220 is simply decreased, the heat radiation capacity of the AC condenser 220 may become small. Thus, as shown in FIG. 13, a thickness dimension D of a heat exchanging portion (a dimension in the flow direction of the cooling air) is set larger than that of a heat exchanging portion of the RA condenser 340 to ensure the heat radiation capacity.
Thus, the cooling air which is not subjected to the heat exchange at the AC condenser 220 and whose temperature is equal to that of the outside air can directly flow into the RA condenser 340, thereby improving the heat radiation capacity of the RA condenser 340.
The thickness dimension D of the heat exchanging portion is increased by a decrease in area of the front surface of the AC condenser 220 to obtain the heat radiation capacity. This facilitates reduction in area of the front surface of the AC condenser 220.

Other Embodiments

Although the present invention has been fully described in connection with the preferred embodiments thereof with reference to the accompanying drawings, it is to be noted that various changes and modifications will become apparent to those skilled in the art.
For example, set positions of the pressure sensors 301 and 302 in the Rankine cycle 300 are not limited to those described in the first embodiment. The pressure sensor 301 may be positioned in any high-pressure side area. The pressure sensor 301 may be preferably provided between the pump. 310 and the heater 320. The pressure sensor 302 may be positioned in the low-pressure side area. The pressure sensor 302 may be preferably provided between the RA condenser 340 and the pump 310.
Set positions and opening directions of the inlets 220 a and 340 a and the outlets 220 b and 340 b of the AC condenser 220 and the RA condenser 340 are not limited to the contents described in each of the above-mentioned embodiments, and may be any other position and direction.
The compressor 210 in the refrigeration cycle 200 is not limited to an engine-driving compressor driven by the engine 10, and also may be an electric compressor driven by an electric motor, or a hybrid compressor driven by an engine and an electric motor.
In the Rankine cycle 300, the pump 310 is driven by the electric motor 311, and the electric generator 331 is connected to the expansion unit 330. Alternatively, the electric motor 311 may be omitted, and the electric generator 331 may serve as a motor generator having both functions of an electric motor and an electric generator. The pump 310 and the expansion unit 330 may be connected to the motor generator.
In this case, in operating of the Rankine cycle 300, first, the motor generator acts as an electric motor to drive the pump 310. When exhaust heat is sufficiently obtained from the engine 10 and the driving force at the expansion unit 330 exceeds the power of the pump 310, the motor generator acts as an electric generator for generating electricity.
This can eliminate a driving source dedicated to drive the pump 310 (the electric motor 311 in each of the above-mentioned embodiments), thereby simplifying the structure of the cycle, while decreasing energy for operating the pump 310.
Such changes and modifications are to be understood as being within the scope of the present invention as defined by the appended claims.

Claims

1. A refrigeration apparatus with an exhaust heat recovery device mounted on a vehicle, comprising:

a refrigeration cycle for allowing a refrigerant for refrigeration to circulate therethrough, the refrigeration cycle including a compressor, a refrigeration-cycle condenser, an expansion valve, and an evaporator which are connected in a circular shape; and

a Rankine cycle for allowing a refrigerant for the Rankine cycle to circulate therethrough, the Rankine cycle including a pump, a heater using exhaust heat from a heat engine of the vehicle as a heating source, an expansion unit, and a Rankine-cycle condenser which are connected in a circular shape,

wherein the refrigeration-cycle condenser and the Rankine-cycle condenser are disposed in predetermined positions of the vehicle in series with respect to a flow direction of external air for cooling, and

wherein the refrigeration-cycle condenser is disposed on an upstream side of the external air with respect to the Rankine-cycle condenser.

2. The refrigeration apparatus with an exhaust heat recovery device according to claim 1, further comprising control means for controlling operations of the refrigeration cycle and the Rankine cycle,

wherein the control means controls number of revolutions of the expansion unit such that an expansion-unit pressure difference in the expansion unit of the refrigerant for the Rankine cycle is equal to or more than a predetermined value, when both the refrigeration cycle and the Rankine cycle are simultaneously operated.

3. The refrigeration apparatus with an exhaust heat recovery device according to claim 2, wherein the control means decreases the number of revolutions of the expansion unit when the expansion-unit pressure difference is smaller than the predetermined value.

4. The refrigeration apparatus with an exhaust heat recovery device according to claim 2, wherein the control means controls the number of revolutions of the expansion unit such that the expansion-unit pressure difference has such a value as to obtain a predetermined appropriate expansion ratio in the expansion unit.

5. The refrigeration apparatus with an exhaust heat recovery device according to claim 2, further comprising:

a high-pressure side pressure detection means located in a high-pressure side area leading from a downstream side of the pump to an upstream side of the expansion unit, the high-pressure side pressure detection means being adapted to detect a high-pressure side pressure of the refrigerant for the Rankine cycle; and

a low-pressure side pressure detection means located in a low-pressure side area leading from a downstream side of the expansion unit to an upstream side of the pump, the low-pressure side pressure detection means being adapted to detect a low-pressure side pressure of the refrigerant for the Rankine cycle,

wherein the control means controls the number of revolutions of the expansion unit based on a difference between the high-pressure side pressure and the low-pressure side pressure, the difference indicating the expansion unit pressure difference.

6. The refrigeration apparatus with an exhaust heat recovery device according to claim 2, further comprising:

a high-pressure side pressure detection means located in a high-pressure side area leading from a downstream side of the pump to an upstream side of the expansion unit, the high-pressure side pressure detection means being adapted to detect a high-pressure side pressure of the refrigerant for the Rankine cycle;

an air temperature detection means disposed between the refrigeration-cycle condenser and the Rankine-cycle condenser, the air temperature detection means being adapted to detect an air temperature of the external air passing through between the refrigeration-cycle condenser and the Rankine-cycle condenser; and

calculation means for calculating a temperature of the refrigerant for the Rankine cycle in the Rankine-cycle condenser, and further a low-pressure side pressure based on an amount of heat radiated at the Rankine-cycle condenser which is balanced with an amount of heat absorbed into the heater by exhaust heat, an amount of the external air passing through the Rankine-cycle condenser, and the air temperature detected by the air temperature detection means,

wherein the control means controls the number of revolutions of the expansion unit based on a difference, indicative of the expansion-unit pressure difference, between the high-pressure side pressure and the low-pressure side pressure.

7. The refrigeration apparatus with an exhaust heat recovery device according to claim 2, further comprising:

an inflow air temperature detection means for detecting an inflow air temperature of the external air before flowing into the refrigeration-cycle condenser and the Rankine-cycle condenser; and

calculation means for calculating a temperature of the external air after passing through the refrigeration-cycle condenser based on an amount of heat radiated at the refrigeration radiator which is balanced with a necessary refrigeration capacity at the evaporator, an amount of the external air passing through the refrigeration-cycle condenser, and the inflow air temperature detected by the inflow air temperature detection means, the calculation means being also adapted to calculate a temperature of the refrigerant for the Rankine cycle in the Rankine-cycle condenser, and further calculating a low-pressure side pressure based on an amount of heat radiated at the Rankine-cycle condenser which is balanced with an amount of heat absorbed into the heater by the exhaust heat, an amount of the external air passing through the Rankine-cycle condenser, and the calculated temperature of the external air after passing through the refrigeration-cycle condenser,

8. The refrigeration apparatus with an exhaust heat recovery device according to claim 1, wherein positions of an inlet and an outlet of the refrigerant in the refrigeration-cycle condenser are positioned in the same area as those of an inlet and an outlet of the refrigerant for the Rankine cycle in the Rankine-cycle condenser as viewed from the flow direction of the external air.

9. The refrigeration apparatus with an exhaust heat recovery device according to claim 1, further comprising an air-introduction flow path portion for allowing the external air to be introduced into the Rankine-cycle condenser from an upstream side of the external air of the refrigeration-cycle condenser through a space between the refrigeration-cycle condenser and the Rankine-cycle condenser, and

an opening adjustment portion for adjusting an area of an opening toward the refrigeration-cycle condenser and an area of an opening toward the air-introduction flow path portion by being moved under control of the control means.

10. The refrigeration apparatus with an exhaust heat recovery device according to claim 1, wherein an area of a front surface of the refrigeration-cycle condenser is made to be smaller than that of a front surface of the Rankine-cycle condenser, and the Rankine-cycle condenser has an area at an upstream side of the external air where the refrigeration-cycle condenser is not superimposed.

11. The refrigeration apparatus with an exhaust heat recovery device according to claim 10, wherein a dimension of the refrigeration-cycle condenser in a flow direction of the external air is set larger than that of the Rankine-cycle condenser.

12. The refrigeration apparatus with an exhaust heat recovery device according to claim 1, wherein an inlet and an outlet of the refrigerant for refrigeration in the refrigeration-cycle condenser is provided to be opened toward an upstream side in a flow direction of the external air.

13. The refrigeration apparatus with an exhaust heat recovery device according to claim 1, wherein an inlet and an outlet of the refrigerant for the Rankine cycle in the Rankine-cycle condenser is provided to be opened in a direction perpendicular to a flow direction of the external air.

14. The refrigeration apparatus with an exhaust heat recovery device according to claim 1, wherein the refrigeration-cycle condenser and the Rankine-cycle condenser are disposed on an upstream side of the external air with respect to a radiator located in a radiator circuit of the vehicle, and

wherein the refrigeration-cycle condenser, the Rankine-cycle condenser, and the radiator are disposed at predetermined positions of the vehicle in series with respect to a flow direction of the external air for cooling.

15. The refrigeration apparatus with an exhaust heat recovery device according to claim 14, wherein the refrigeration-cycle condenser, the Rankine-cycle condenser, and the radiator are disposed on a front side in an engine room, at a rear side of a vehicle grill.