AU2016216738B2 - Cooling of a space accommodating an occupant in a vehicle - Google Patents

Abstract

H:\ejl\Interwoven\NRPortbl\DCC\EJL\l0917047_1.docx-19/08/2016 A system for cooling an interior space for accommodating an occupant in a vehicle provided with a power source, the system comprising: at least one refrigeration apparatus 5 comprising a refrigeration circuit including a compressor, which is driveable by the power source, and an evaporator; an insulated reservoir holding a phase-change medium within which the/each evaporator extends, such that said medium can be cooled by the evaporator(s) to an extent that an amount thereof freezes from a liquid state; a cooling fluid circuit including a heat exchanger; a pump operable to pump the cooling fluid in the circuit 10 from the reservoir to the heat exchanger and thence back to reservoir, whereby the frozen medium gradually melts; and means to effect a flow of air over the heat exchanger and into the interior space. o U I- CC.) Coo z

Description

COOLING OF A SPACE ACCOMMODATING AN OCCUPANT IN A VEHICLE

Field of the Invention

The present invention relates to a system for cooling an interior space for accommodating an occupant in a vehicle. The invention also relates to an assembly comprising the system and vehicle, and to a method of establishing a source of cooling for a vehicle in which method the system is operated.

The invention has particular, though not exclusive, application to a vehicle, such as a freight, cargo or bulk material-transporting vehicle (e.g. a truck, boat or train) or a surveillance, armoured or military vehicle, which is driven or piloted over a period of time (e.g. a shift) and in which a driver, pilot or crew of the vehicle is thereafter accommodated so as to be able to sleep, or otherwise rest, or to perform tasks in the vehicle when the vehicle is parked up or moored and its source of locomotive power is not running.

Background

Generally speaking, maximum driving times for drivers of road haulage vehicles are dictated by statutory regulations. Where the vehicle cannot reach its destination within the maximum daily driving time allowable, it is typically necessary that the driver, for his or her comfort, health and safety, park up the vehicle and rest for a minimum period of time before resuming driving. Often, a driver cabin of the vehicle is, to this end, provided with a bed in which the driver can sleep during the rest period. In circumstances where the outside air is warm, it is generally necessary to operate an air conditioner or cooler to maintain air temperature in the cabin or cab of the parked-up vehicle at or below a certain maximum.

Although the vehicle cabin will typically be provided with an air conditioner powered by an onboard battery of the vehicle to keep the driver cool, the power demand of such an air conditioner is generally so great that the engine must remain running, or a dedicated auxiliary power supply must be provided, for the air conditioner to be able to run for any

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-2appreciable length of time.

There is an ongoing need for efficient provision of cooling to air in an interior space which accommodates an occupant in a vehicle, particularly when an engine, or other drive which provides locomotive power to the vehicle, is not running.

Summary of the Invention

According to a first aspect of the present invention, there is provided a vehicle comprising a sleeper cab and a drive for providing locomotive power to the vehicle, the vehicle being provided with an electrical power source, arranged to be charged by said drive, and a system for cooling an interior space for accommodating an occupant in the sleeper cab, wherein the system comprises:

at least one refrigeration apparatus comprising a refrigeration circuit including a compressor, which is arranged to receive power from the power source so as to be driven thereby, and an evaporator;

an insulated reservoir holding a phase-change medium within which the/each evaporator extends, such that said medium can be cooled by the evaporator(s) to an extent that an amount thereof freezes from a liquid state;

a cooling fluid circuit including a heat exchanger;

a pump operable to pump the cooling fluid in the circuit from the reservoir to the heat exchanger and thence back to reservoir, whereby the frozen medium gradually melts;

means to effect a flow of air over the heat exchanger and into the interior space; and a controller arranged to detect whether said drive is running or an ignition of the vehicle is on, and configured to preclude driving of the compressor(s) when said drive is not running or said ignition is not on.

According to a second aspect of the present invention, there is provided a vehicle comprising a sleeper cab and a drive for providing locomotive power to the vehicle, the vehicle being provided with an electrical power source, arranged to be charged by said drive, and a system for cooling an interior space for accommodating an occupant in the sleeper cab, wherein the system comprises:

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-3 at least one refrigeration apparatus comprising a refrigeration circuit including a compressor, which is driveable by the power source, and an evaporator;

an insulated reservoir in which the/each evaporator extends or is disposed, the reservoir holding a phase-change medium which is in heat exchange communication with the evaporator(s) whereby it can be cooled to an extent that an amount thereof freezes from a fluid or liquid state;

a cooling fluid circuit including a heat exchanger;

a pump operable to pump the cooling fluid in the circuit from the reservoir to the heat exchanger and thence back to reservoir, whereby the frozen medium gradually melts;

means to blow air, over or via the heat exchanger, into the interior space such that the interior space is cooled; and a controller arranged to detect whether said drive is running or an ignition of the vehicle is on, and configured to preclude driving of the compressor(s) when said drive is not running or said ignition is not on.

Preferably, the or each evaporator comprises a coil arranged in the phase-change medium.

In a preferred embodiment of the present invention, the cooling fluid is isolated from the phase-change medium and in heat exchange communication with the phase-change medium so as to be cooled by the phase-change medium. Preferably, part of the cooling fluid circuit is arranged within the reservoir and/or the phase-change medium whereby the cooling fluid is in said heat exchange communication with the phase-change medium. Preferably, said part of the cooling fluid circuit comprises at least one coil. Preferably, the or each evaporator comprises a coil in which a respective said coil of the cooling fluid circuit is arranged. Preferably, the or each evaporator comprises a coil concentric with which a respective said coil of the cooling fluid circuit is arranged. Preferably, the cooling fluid circuit includes a reservoir holding a supply of said cooling fluid. Preferably, the reservoir of said cooling fluid circuit is arranged at least partially within said insulated reservoir and/or within said phase-change medium. Preferably, said pump is arranged in the reservoir of said cooling fluid circuit. The cooling fluid may comprise a glycol solution.

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-4In another preferred embodiment of the present invention, the cooling fluid is said phasechange medium, and the pump is operable to pump said medium in a fluid or liquid state.

Preferably, the system comprises plural said refrigeration apparatuses which are operationally independent such that, where driving of the compressor of one of the apparatuses is discontinued, the compressor of the or each other apparatus can continue to operate such that the phase-change medium is cooled. Preferably, the number of refrigeration apparatuses is two.

Preferably, the system comprises, at least one sensor arranged to sense temperature of the phase-change medium, and a controller with which the sensor(s) is/are in communication and which is is operable to permit driving of at least one said compressor when a said sensor senses a temperature of the phase-change medium which is less than a threshold temperature, and to preclude driving of at least one said compressor when a said sensor senses a temperature of the phase-change medium which is equal to or greater than said threshold temperature.

Preferably, the system comprises plural said sensors each of which is associated with a respective said refrigeration apparatus, and the controller is operable, when either or any said sensor senses a temperature of the phase-change medium which is less than said threshold temperature, to permit driving of the compressor of the refrigeration apparatus with which that sensor is associated, and, when either or any said sensor senses a temperature of the phase-change medium which is equal to or greater than said threshold temperature, to preclude driving of the compressor of the refrigeration apparatus with which that sensor is associated. Preferably, each sensor is on or adjacent the evaporator of the refrigeration apparatus with which it is associated.

Preferably, the system comprises a controller, arranged to operate the compressor(s), and at least one detector in communication with the controller and arranged to detect an amount of the medium which is frozen in the insulated reservoir, the controller being arranged to permit driving of at least one said compressor when a said detector detects that a frozen amount of

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-5 said phase change medium is less than a threshold quantity and to preclude driving of at least one said compressor when a said detector detects that a frozen amount of said phase change medium is greater than or equal to the threshold quantity.

Preferably, the system comprises plural said detectors each of which is associated with a respective said refrigeration apparatus, and the controller is operable, when either or any said detector detects that an amount of the medium which is frozen in the reservoir is less than a threshold quantity, to permit driving of the compressor of the refrigeration apparatus with which that detector is associated, and, when either or any said detector detects that an amount of the medium which is frozen in the reservoir is greater than or equal to the threshold quantity, to preclude driving of the compressor of the refrigeration apparatus with which that detector is associated. Preferably, each detector is on or adjacent the evaporator of the refrigeration apparatus with which it is associated.

Preferably, the or each detector or sensor is arranged in said insulated reservoir.

Preferably, the system is configured such that the threshold temperature or quantity is adjustable and including a controller or adjustor operable to set the threshold temperature or quantity.

Preferably, the phase-change medium comprises a eutectic composition.

The phase-change medium may comprise a glycol solution.

Preferably, the or each compressor is driveable by a battery of the vehicle which constitutes the power source.

Preferably, said means comprises a fan.

Preferably, the system includes a thermostat arranged to detect air temperature in said space and configured to communicate with said pump such that operation of the pump is permitted when the detected air temperature is at or above a threshold value and precluded when said

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-6air temperature is below said threshold value.

Preferably, the heat exchanger is arranged in said interior space.

Preferably, the system includes a cooled air output unit arranged in or adjacent said interior space, the unit comprising at least one control operable to effect any one or more of: switching said means on and off;

adjusting an output of said means; and adjusting said threshold value.

Preferably, said unit includes at least one intake vent and is operable to draw air from the space, through the intake vent(s), to the thermostat whereby the thermostat detects the temperature of that air, whereby the detection of air temperature in said space is effected.

Preferably, the unit includes said means and is configured such that operation of said means effects the drawing of air from the space through the intake vent(s).

Preferably, the unit includes said thermostat.

Preferably, the system is an air conditioning system.

Preferably, the pump is driveable by said power source.

Preferably, said means is driveable by said power source.

In preferred embodiments of the invention, the vehicle has a battery arranged to be charged by said drive of the vehicle, when the drive is running. Generally speaking, the vehicle will include an alternator via which the power source is charged by said drive.

Preferably, there is at least one period over which said drive does not run, and, throughout the or each period, said power source does not drive the compressor(s).

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-7Preferably, the or each refrigeration apparatus, or the compressor and evaporator thereof, is situated at an exterior of the vehicle.

Preferably, the insulated reservoir is situated at an exterior of the vehicle.

Preferably, said exterior of said vehicle is on or adjacent a cab or cabin of the vehicle.

Preferably, said exterior of said vehicle is at a rear of the cab or cabin.

Preferably, said vehicle is provided with a bed in the interior space.

Preferably, the power source comprises a battery and/or alternator of the vehicle.

Preferably, the drive comprises an engine of the vehicle.

In one preferred embodiment of the invention, the vehicle is a truck or truck prime mover. In another preferred embodiment of the invention, the vehicle is a boat. In another preferred embodiment of the invention, the vehicle is a train locomotive.

According to a third aspect of the present invention, there is provided a method of establishing a source of cooling for an interior space for accommodating an occupant in a vehicle, wherein:

the vehicle accords with the first or second aspect, said interior space being in said sleeper cab; and when said drive of the vehicle is running, the power source drives the compressorof at least one said refrigeration apparatus such that said medium is cooled by the evaporator of that apparatus to an extent that said amount of the medium freezes.

In one preferred embodiment of the invention, said amount of said medium is the entirety of said medium.

Preferably, there is at least one period over which said drive does not run, and, throughout the or each period, said power source does not drive the compressor(s).

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-8According to a fourth aspect of the present invention, there is provided a vehicle according to the first or second aspect, wherein:

the sleeper cab accommodates said occupant;

said drive is not running;

said pump is operating to pump the cooling fluid in the circuit from the reservoir to the heat exchanger and thence back to reservoir, whereby said frozen medium gradually melts; and said means is operating such that said air is blowing or flowing over or via said heat exchanger into the interior space, whereby said interior space is cooled.

Brief Description of the Drawings

The invention will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which:

Figure 1A is a schematic view of a cooling system for a vehicle according to a first preferred embodiment of the present invention, in a refrigeration or pre-cooling phase;

Figure IB is a schematic view of the system of the first embodiment in a cabin air cooling phase;

Figure 2 shows components of a vehicle cooling system according to a second preferred embodiment of the invention;

Figure 3 is a schematic view of the cooling system of the second embodiment;

Figure 4 is a schematic view showing details of a control system of the cooling system of the second embodiment;

Figure 5 is a rear view of a sleeper cab of a vehicle to which the system of either embodiment is applied, showing an exterior unit of the system mounted to the rear wall of the sleeper cab; and

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-9Figure 6 shows an adjustable cold air output unit of the system of either embodiment installed in the cab.

Detailed Description of the Preferred Embodiments of the Invention

The content of Australian provisional patent application no. 2015903366, filed 19 August 2015, is incorporated herein by reference.

Figure 1A is a schematic view showing a system 1 for cooling a sleeper cab of a truck when the truck engine is not running. The system 1 comprises a refrigeration apparatus 10 operable according to a conventional refrigeration cycle, the apparatus 10 including a refrigeration circuit 10A comprising an evaporator 11, a compressor 12, a condenser 13 and an expansion device 14, which comprises a thermal expansion valve but may instead comprise a capillary restriction tube without departure from the invention, the circuit containing conventional refrigerant such as R134A. The compressor(s) 12 in each of the embodiments described and illustrated herein may be of the twin hermetic, three-phase type. The condenser(s) 13 in each of the embodiments described and illustrated herein may be of the cross-finned type.

The refrigeration apparatus 10 further comprises a dryer 15, arranged on the circuit 10A between the condenser 13 and expansion device 14, which dryer may be a solid-core filter dryer. The system 1 additionally comprises a two-speed cooling fan 16 operable to draw air over the condenser 13 and a housing 17 having an upper compartment 17A in which the components 12 to 16 are arranged, including a cover 17A’ which is removable such that those components can be accessed, the compartment 17A being adequately ventilated such that outside air can be drawn by the fan 16 into the housing 17, as will be described in further detail later.

The system 1 further includes a pod 20, comprising a thermal tank 21 having an insulated wall structure 22 which bounds an interior of the tank 21 in which a coil 19 defining, or forming part of, the evaporator 11 is housed, and in which a phase-change medium 30 is

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- 10contained, the tank 21 thus defining a reservoir for the medium 30. The pod 20 is housed in a lower compartment 17B of the housing 17, which compartment includes a cover 17B’ which can be removed such that the pod 20 can be accessed. The wall structure 22 comprises an outer lining or layer 22A, an inner liner or layer 22B, in contact with the phase-change material 30, and insulation 22C, e.g. polyurethane foam, between the outer wall lining/layer and inner liner/layer.

In the present embodiment, the medium 30 is a eutectic mixture of glycol (e.g. ethylene glycol or propylene glycol) and water, and has a freezing point of between -6°C and -2°C at ambient pressure. In an alternative embodiment of the invention, the medium may instead consist of a single chemical compound which preferably likewise has a freezing point between -6°C and -2°C at ambient pressure.

The refrigeration apparatus 10, fan 16 and pod 20 are integrated in a single unit 40, an outer casing of which defines the housing 17. Referring to Figure 5, the unit 40 is mounted to an exterior side of a rear wall of the sleeper cab 100 of the vehicle, and orientated such that the housed compressor 12, condenser 13, dryer 15 and valve 14, as well as the fan 16, are at a higher level than the pod 20, the fan 16 being mounted to a rear wall of the housing 17. The upper compartment 17A is configured, on opposite lateral sides thereof, with vents 16A arranged such that operation of the fan 16 effects intake of outside air into the compartment 17A, which air flows over the condenser to cool it and is thence expelled from the compartment 17B via the fan 16.

The compressor 12 is electrically coupled, via wiring, to an onboard lead-acid battery (typically 12 volts DC or 24 volts DC) or alternator 50 of the vehicle.

The system 1 includes a temperature sensor or probe 42 which is mounted to the tank wall structure 22 and projects therefrom into the medium 30 in the reservoir, the probe 42 being spaced from the coil 19 in the reservoir. The sensor/probe 42 will be described in further detail later.

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- 11 The system 1 further comprises a control module 60 which is electrically coupled to the sensor/probe 42 via wiring 43, is electrically coupled to the compressor 12 via wiring 44, is electrically coupled to the battery/alternator 50 and compressor 12 via wiring 45, and is electrically coupled, via wiring 46, to a probe or sensor 47 arranged to detect temperature of the condenser 13 and to provide (via that wiring) a signal indicative of the detected temperature to the control module 60, which is operable to increase the speed of fan 16 where the detected temperature increases so as to equal or exceed an adjustably settable threshold and to decrease the speed of that fan where the detected temperature decreases so as to be below that threshold. The control module 60 will also be described in further detail later.

The system 1 additionally includes an adjustable cooled air output unit 70, shown also in Figure 6, which is mounted inside the sleeper cab 100. The unit 70 comprises a blowing device, comprising a fan 71, and a heat exchanger, comprising a coil 72. The system 1 also includes a cooling fluid supply line 73 an intake end of which is connected to a lower part of the reservoir and an output end of which is connected to an input end of the coil 72, and a cooling fluid return line 74, an input end of which is connected to an output end of the coil 72 and an output end of which is connected to an upper part of the reservoir. Additionally, the system 1 includes a pump 75, arranged on the supply line 73 and operable to pump liquid medium 30 from the reservoir, along the supply line 73, through the coil 72 and thence along the return line 74 whereby it is returned to the reservoir, the reservoir, line 73, coil 72 and return line 74 thus defining a cooling fluid circuit 90 of the system 1, in which circuit the phase-change medium is the cooling fluid. The unit 70 includes direction-adjustable cooled air output vents 76A and a return air intake vent 76B, and is configured such that operation of the fan 71 causes air in the interior of the cab 100 to be drawn through the intake vent 76B, directed over/across the coil 72 so as to be cooled thereby, and then expelled through the vents 76A into the sleeper cab interior. The unit 70 includes an adjustor 77 operable to adjust the speed of the fan 71, and a thermostat 78, including a return air temperature sensor 78A, electrically coupled to the control module 60 via wiring 79, to sense the temperature of the air intaken through the vent 76B and to provide to the module 60 a signal indicative of the sensed temperature, the

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- 12module 60 being electrically coupled to the pump 75, via wiring 80, and configured to permit driving of the pump 75, and thus supply of chilled cooling fluid to the unit 70 such that it cools the air in the cab interior, if the signal indicates that the sensed temperature is at or above a temperature setting of the thermostat 78, and to preclude that driving, and thus the supply of the chilled fluid to the unit 70, if the signal indicates that the sensed temperature is below the temperature setting (though the fan 71 can continue running to circulate air in the cab interior when the pump 75 is not operating). The unit 70 includes an adjustor 78B operable to vary the temperature setting of the thermostat 78A.

The system 1 further comprises a drain 81 arranged to collect condensate, which precipitates out of the air blown over the coil 72, and to output the condensate to an exterior of the vehicle.

Operation of the system 1, firstly in a pre-cooling phase and thereafter in an air cooling phase, will now be described.

Referring firstly to Figure 1A, when the engine of the vehicle (in which the system 1 is installed) is running, the control module 60, which is electrically coupled via wiring (not shown) to the vehicle ignition system, receives via that wiring an electrical current on the basis of which it sends a signal, along the electrical line 45, whereby current is permitted to flow, via electrical line 41, from the battery or alternator 50 to the compressor 12 for the purposes of powering the compressor 12 and thus the refrigeration apparatus 10/unit 40. The probe 42 senses a temperature of the medium 30 (in a liquid state) at a position remote from the coil 19 and outputs to the control module 60, via line 43, an electrical signal indicative of the temperature detected. Where the signal indicates that the temperature is greater than a pre-set minimum (which minimum can be set and altered by an adjustor (not shown) of the control module 60 or unit 70), the control module 60 outputs a signal, along wiring 44, to the compressor 12, permitting it to run under the power supplied to it by the battery/alternator 50. The apparatus 10/unit 40 thus runs whereby the evaporating refrigerant flowing through the coil 19 absorbs heat from the medium 30. After a period of time, the medium 30 will begin to freeze, whereby a progressively increasing volume of

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- 13 solidified medium 30’, shown in Figure IB, forms in the tank, including in particular on the coil 19. As long as the engine remains running and the temperature as detected by probe 42 remains at or above the minimum threshold, the apparatus 10 will continue to refrigerate the medium 30. (If the engine/ignition is turned off, the resulting absence of an electrical output from the module along electrical line 45 will cause the battery/alternator 50 to cease providing power to the compressor 12, though the supply of power, and thus driving of the compressor 12, will resume when the engine/ignition is turned on again). Because the probe 42 is spaced from the evaporator/coil 19, the temperature it detects at any given time will be greater than the temperature of the medium 30 at/adjacent the evaporator/coil 19, though the latter temperature, and thus the amount of medium 30 which has solidified/frozen, can nevertheless be estimated or deduced on the basis of the sensed temperature. Accordingly, the sensed temperature’s reaching the pre-set minimum is indicative of a maximum allowable amount of medium 30 having frozen. The control module 60 thus effectively detects, on the basis of the sensed temperature, the amount of medium which is frozen. It will be appreciated that, without departure from the invention, the detector may comprise, instead of the one probe 42 shown in Figures 1A and IB, a plurality of probes arranged at spaced apart positions in the tank, in which case the control module would be configured to cause the compressor 12 to stop running upon an average of the temperatures sensed by the plural probes reaching the pre-set minimum. It will also be appreciated that, without departure from the invention, alternative means of detecting how much of the medium is frozen are possible. For example, the detector may comprise a level sensor/switch which detects the level of liquid medium in the tank, which level will increase as the amount of frozen medium increases, since the medium expands when it freezes. Alternatively, the sensor/detector may be a mechanical one arranged to be impinged upon or abutted by a body of the medium in the solid state which has grown outwardly from the evaporator, where that body is sufficiently large. The system 1 is configured such that the settable minimum temperature cannot be lower than a value at which there is an insufficient amount of the medium 30 remaining in the liquid phase to be pumped around the aforementioned cooling fluid circuit.

An exemplary “fully charged” condition of the cooling medium 30/30’ is shown in

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- 14Figure IB. While the vehicle ignition/engine remains on, the compressor 12 will then, if sufficient time passes, intermittently operate to maintain the minimum temperature condition in the tank, to compensate for heat absorption in the medium 30/30’ under a temperature differential across the tank walls.

The medium/eutectic mixture 30, advantageously, forms a “slurry”, consisting of liquid and solid particles/crystals of ice suspended in that liquid, in the tank as it freezes - it does not instantaneously freeze throughout upon the temperature therein reaching its freezing point (in the way that water, for example, may do) - whereby it can be ensured that a quantity of the medium/mixture 30 will remain fluid so as to be pumpable around the cooling liquid circuit. A filter 73A is arranged at the inlet/intake end of the line 73 to preclude intake of excessively large particles of solidified medium 30’ into the line 73.

When the driver’s shift concludes and the vehicle is thus parked up for the driver to sleep/rest, the driver turns on the unit 70 of the cold air outputting apparatus, by operating an on/off switch 70A of the unit 70, and, as and if appropriate, adjusts the fan speed via controller 77, adjusts the desired cabin air temperature via the thermostat adjustor 78B and/or operates a switch 70B of the unit 70 which is configured to toggle between a highvoltage range fan speed setting and a low-range fan speed setting. If the thermostat 78 senses a temperature of the return cabin air (drawn through vent 76B) which is greater than the temperature setting input via the thermostat adjustor 78B, it will output an electrical signal, via electrical line 79, to the control module 60 which will, in turn, output an electrical signal to the pump 75, via electrical line 80, such that the pump 75 receives power from the battery 50 and operates to pump liquid medium 30 through the liquid circuit, the air blown by the fan 71 thus being cooled as it passes over the medium-carrying coil 72 before being discharged through the vents 76A, whereby the cabin air is cooled. When the return air temperature detected by the thermostat 78 has reduced to the pre-set level, the control module causes the pump 75 to cease operating, so that the chilled liquid medium 30 stops circulating, though the fan 71 will continue to operate, such that the air within the cabin continues to be circulated. The pump 75 will remain off until the sensed return air temperature increases above the pre-set temperature level, whereupon it will

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- 15 resume operation to cool the cabin air. The cabin air temperature is thus maintained substantially constant.

The control module 60 is located in a sealed enclosure within the casing of the unit 40 and performs control functions of the system, including those outlined above. The module 60 comprises a programmable digital thermostat with LED display and with twin probes and twin control operatives, a 24VDC-to-12VDC converter (in the case of a 24VDC system) or 12VDC-to-6VDC converter (in the case of a 12VDC system), providing for the two speeds of the condenser fan 16. The module precludes total freeze of the eutectic solution, effects compressor start delay (whereby the compressor 12 is not permitted to start up until a predetermined period from startup of the vehicle engine has elapsed) and under/over voltage protection, and protects the vehicle electrical power source by precluding refrigeration when the vehicle engine/ignition is off.

The system 1 is sized and configured, such that, when the cooling source is fully established in the tank 21 (i.e. the fully charged condition is realised), the pump 75 and output unit 70 can operate for at least 7 hours, being a typical prescribed minimum driver “holdover” time. Advantageously, during the holdover period, the only power draw by the system 1 is that for operating the pump 75 and fan 71, which is minimal, the pump 75 and fan 71 operating at about 1.5 amps and 2 amps respectively in the case of a 24VDC model, and at about 3 amps and 4 amps respectively in the case of a 12VDC model, which will have negligible impact on the degree of charge of the battery 50 over the holdover period. More particularly, throughout the holdover period, no power consumption is dedicated to refrigeration, there being a sufficient capacity for cooling in the chilled medium 30, owing in particular to the latent heat of fusion of the amount of that medium which is frozen.

Shown schematically in Figure 3 is a cooling system Γ for a vehicle according to a second preferred embodiment of the present invention, in respect of which like reference numerals are used to refer to like features. The system Γ, like the system 1, is for cooling a sleeper cab 100 of a truck when the truck engine is not running. The system Γ comprises a pair of refrigeration apparatuses 10', each of which is operable independently of the other, so that,

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- 16should one apparatus fail to run (e.g. in the event of a fault condition), the other can continue to operate such that the phase-change medium can continue to be cooled/frozen. Each apparatus 10' is operable according to a conventional refrigeration cycle and includes a refrigeration circuit 10A' comprising an evaporator 11, a compressor 12 (arranged to be powered by the batter/alternator), a condenser 13 and an expansion device 14, which comprises a capillary restriction tube though may instead comprise a different expansion device, such as a thermal expansion valve, without departure from the invention. The circuit contains conventional refrigerant such as R134A. Each refrigeration apparatus 10’ further comprises a dryer 15, arranged on the circuit thereof between the condenser 13 and the expansion device 14 in that apparatus, and a fan 16 operable to blow air over the condenser 13. The system Γ comprises housing 17, including upper compartment 17A in which the components 12 to 16 are arranged, which compartment includes cover 17A’ which is removable such that those components can be accessed.

The system Γ further includes a pod 20' comprising thermal tank 21, having an insulated wall structure 22 which bounds an interior of the tank 21 in which side-by-side coils 19 of the evaporators 11 are contained. The coils 19 are, like the coil 19 in the system 1, submerged in the phase-change medium 30, which may be the aforementioned eutectic mixture of glycol and water or single chemical compound mentioned previously in respect of the system 1. Referring to Figure 5, the refrigeration apparatuses 10', fan 16 and pod 20' are integrated into a single unit 40', an outer casing of which defines the housing 17'. The wall structure 22 of the pod tank 21 comprises linings/layers 22A and 22B, as previously described, and insulation 22C as also previously described.

In each refrigeration circuit 10A, a vibration elimination line extends between the capillary restriction tube and the coil 19.

The system 1' further includes temperature sensors or probes 42', each of which is associated with, and arranged adjacent to, a respective one of the evaporator coils 19.

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- 17The system Γ further comprises a control module 60' which is electrically coupled to the sensors/probes 42', the compressors 12, the battery/altemator 50 and the cooled air output unit 70 which is mounted inside the sleeper cab 100. The control module 60’ is also electrically coupled to each of the sensors/probe 42’ and to each of probes/sensors 47, each of which probes/sensors 47 is arranged to detect temperature of a respective one of the condensers 13 and to provide to the control module 60’ a signal indicative of that temperature, the control module 60’ being operable to increase the speed of fan 16 where either of the detected temperatures increases to a level above the adjustably settable threshold and to decrease the speed of that fan where the detected temperature decreases to a level below that threshold. The control module 60’ will also be described in further detail later.

The system 1' also includes a cooling fluid circuit 90' through which cooling fluid, which has been chilled at a location in the tank 21, is supplied to the unit 70 and thence returned to the tank 21 (to be re-cooled), though in this embodiment, unlike in the previous embodiment, the cooling fluid is not the phase-change medium but rather a separate liquid 95, which may, for example, comprise a glycol solution and is isolated from (but stored in heat exchange relationship with) the phase-change medium 30. More particularly, the pod 20' includes a reservoir 91, defined by a tank, which is supported from the wall structure 22 and extends into the interior of the tank 21, the reservoir 91 holding a supply of the cooling fluid 95 in a part thereof which is submerged in the phase-change medium 30 (whereby heat is drawn from the liquid 95 through the wall(s) of the reservoir 91, into the phase change medium 30, such that the liquid 95 in the reservoir is cooled by the phase-change medium), and a pump 75' is submerged in the cooling fluid supply within the reservoir 91 and operable to supply chilled fluid 95 from the reservoir 91 to the unit 70, and into the coil 72 thereof, via supply line 73' and thence to return the (heated) cooling fluid 95, from the unit 70, via return line 74', to a location within the tank 21 so it can be re-chilled; specifically an output end of the return line 74' is connected to input ends of cooling coils 92 each of which is submerged in the phase-change medium 30 and arranged within a respective one of the coils 19 and has an output end connected to a line 93 to return the cooling fluid 95 to the interior of the reservoir 91. The

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- 18 cooling fluid circuit 90’ thus comprises the reservoir 91 and pump 75’, the supply line 73’, the coil 72, the return line 74’, the coils 92 and the line 93.

Details of components which are housed in the upper compartment 17A’ are shown in Figure 2. The control module 60’, like the control module 60, includes a waterproof casing 61, which houses electrical componentry/circuitry of the module, a console 62 which includes buttons 62A and an associated screen 62B for manipulating/adjusting settings of the controller, and LEDs 62C operable to indicate any of plural fault conditions which can arise in the cooling system (detected by on-board diagnostics in the control system), those conditions including a wiring glitch or faulty condenser fan (in the event of which the control system can discontinue operation of the cooling system or compressor), an overvoltage (in the event of which the control system can preclude supply of power to the cooling system to prevent resulting damage to it) and an undervoltage (in the event of which the controller can preclude operation of the cooling system for the purposes of conserving (limited) power stored in the vehicle battery) - among several other possible fault conditions . Buttons 62A are operable to set operating parameters of the cooling system, including the value of the aforementioned phase-change medium threshold temperature (at which driving of a said compressor is to be discontinued), condenser fan cooling speed and threshold voltage value for an overvoltage or undervoltage condition. The controller includes a temperature control unit, such as that called the “STC-600” supplied by KI&BNT Electronics Co., Ltd., of which the console 62 is a part.

Housed in the compartment 17A is a fill point 94 at which fresh liquid 95 can be supplied to the reservoir 91, and a fill point 23 at which fresh phase-change medium 30 can be supplied to the tank 21.

Shown in Figure 4 is a wiring diagram for the system 1’, in which reference numeral 110 denotes terminals of battery 50, reference numeral 112 denotes a bypass switch of system 1’, allowing for refrigeration apparatuses 10’ to operate when vehicle engine/ignition is off, and reference numeral 114 denotes circuitry of the LEDs 62C.

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- 19The control module 60’, like the module 60, performs control functions of the cooling system, including those outlined above, and, as will be clear from the foregoing, comprises a programmable digital thermostat with LED display and with twin probes and twin control operatives, a 24VDC-to-12VDC converter (in the case of a 24VDC system) or 12VDC-to-6VDC converter (in the case of a 12VDC system), providing for the two speeds of the condenser fan.

Operation of the system 1’, firstly in the pre-cooling phase and thereafter in the air cooling phase, will now be described, with reference to Figure 3.

When the engine of the vehicle in which the system 1’ is installed is running, the control module 60’ which is electrically coupled to the vehicle ignition system, receives an electrical current on the basis of which it sends a signal whereby current is permitted to flow from the battery or alternator 50 to the compressors 12 for the purposes of powering the compressors 12 and thus the refrigeration apparatuses 107unit 40’. Each of the probes 42’ senses a temperature of the medium 30 at its respective position and outputs to the control module 60’ an electrical signal indicative of the temperature it detects. Where the signal from either/each of the probes 42’ indicates that the temperature is greater than a pre-set minimum, which minimum can be set or altered using buttons 62A/screen 62B (or, in a variant embodying the invention, via an adjustor (not shown) of the unit 70), the control module 60’ outputs a signal to the compressor 12 of the circuit 10A with which that probe is associated, permitting it to run under the power supplied to it by the battery/alternator 50. The apparatus 10/unit 40 thus runs whereby the evaporating refrigerant flowing through the coil 19 absorbs heat from the medium 30. After a period of time, the medium 30 will begin to freeze, whereby a progressively increasing volume of solidified medium forms in the tank 21, including in particular on the coils 19. As long as the engine remains running and the temperature as detected by either probe 42’ remains above the minimum threshold, the apparatus 10’ with which that probe is associated will continue to refrigerate the medium 30. (If the engine/ignition is turned off, the resulting absence of an electrical output from the module will cause the battery/alternator 50 to cease providing power to the compressors 12, though the supply of power, and thus driving

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-20of the compressors 12, will resume when the engine/ignition is turned on again). Because the probes 42’ are spaced from the evaporators/coils 19, the temperature they detect at any given time will be greater than the temperature of the medium 30 at/adjacent the evaporator/coil 19, though the latter temperature, and thus the amount of medium 30 which has solidified/frozen, can nevertheless be estimated or deduced on the basis of the sensed temperature. Accordingly, the sensed temperature’s reaching the pre-set minimum is indicative of a maximum allowable amount of medium 30 having frozen. Advantageously, because, in this embodiment, the cooling fluid 95 is a fluid other than the phase-change medium 30, that maximum allowable amount can be the entirety of the medium 30. The control module 60’ effectively detects, on the basis of the sensed temperature, the amount of medium which is frozen. It will be appreciated that, without departure from the invention, the respective detector associated with each of the two circuits 10A/refrigeration apparatuses 10’ may comprise, instead of the one probe 42’, a plurality of probes arranged at spaced apart positions, in which case the control module 60’ would be configured to cause the respective compressor 12 to stop running upon an average of the temperatures sensed by the plural probes reaching the pre-set minimum. It will also be appreciated that, without departure from the invention, alternative means of detecting how much of the medium is frozen are possible, as discussed above.

While the vehicle ignition/engine remains on, the compressors 12 will then, if sufficient time passes, intermittently operate to maintain the minimum temperature condition in the tank 21, to compensate for heat absorption in the medium 30/30’ under a temperature differential across the wall(s) 22 of the tank 21.

When the driver’s shift concludes and the vehicle is thus parked up for the driver to sleep/rest, the driver turns on the unit 70 of the cold air outputting apparatus, by operating on/off switch 70A, and, as and if appropriate, adjusts the fan speed via controller 77, adjusts the desired cabin air temperature via the thermostat adjustor 78B and/or operates switch 70B. If the thermostat 78 senses a return air temperature which is greater than the temperature setting input via the thermostat adjustor 78B, it will output an electrical signal to the control module 60’ which will, in turn, output an electrical signal to the pump 75’,

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-21 such that the pump 75’ receives power from the battery/alternator 50 and operates to pump the liquid 95 from the reservoir 91 through the liquid circuit90’, the air blown by the fan 71 thus being cooled as it passes over the medium-carrying coil 72 before being discharged through the vents 76, whereby the cabin air is cooled. When the return air temperature detected by the thermostat 78 has reduced to the pre-set level, the control module 60’ causes the pump 75’ to cease operating, so that the chilled liquid 95 stops circulating, though the fan 71 will continue to operate, such that the air within the cabin continues to be circulated. The pump 75’ will remain off until the sensed return air temperature increases above the pre-set temperature level, whereupon it will resume operation to cool the cabin air. The cabin air temperature is thus maintained substantially constant.

The system 1’ is sized and configured such that, when the cooling source is fully established in the tank 21 (i.e. the fully charged condition is realised), the pump 75’ and output unit 70 can operate for at least 7 hours, being a typical prescribed minimum driver “holdover” time. Advantageously, during the holdover period, the only power draw by the system 1 is that for operating the pump 75 and fan 71, which is minimal, the pump 75 and fan 71 operating at about 1.5 amps and 2 amps respectively in the case of a 24VDC model, and at about 3 amps and 4 amps respectively in the case of a 12VDC model, which will have negligible impact on the degree of charge of the battery 50 over the holdover period. More particularly, throughout the holdover period, no power consumption is dedicated to refrigeration, there being a sufficient capacity for cooling in the chilled medium 30, owing in particular to the latent heat of fusion of the amount of that medium which is frozen.

While various embodiments of the present invention have been described above, it should be understood that they have been presented by way of example only, and not by way of limitation. It will be apparent to a person skilled in the relevant art that various changes in form and detail can be made therein without departing from the spirit and scope of the invention. Thus, the present invention should not be limited by any of the above described exemplary embodiments.

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2016216738 19 Aug 2016

-22Throughout this specification and the claims which follow, unless the context requires otherwise, the word comprise, and variations such as comprises and comprising, will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that that prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of 10 endeavour to which this specification relates.

Claims (20)

1. Claims

   1. A vehicle comprising a sleeper cab and a drive for providing locomotive power to the vehicle, the vehicle being provided with an electrical power source, arranged to be charged by said drive, and a system for cooling an interior space for accommodating an occupant in the sleeper cab, wherein the system comprises:

   at least one refrigeration apparatus comprising a refrigeration circuit including a compressor, which is arranged to receive power from the power source so as to be driven thereby, and an evaporator;

   an insulated reservoir holding a phase-change medium within which the/each evaporator extends, such that said medium can be cooled by the evaporator/s) to an extent that an amount thereof freezes from a liquid state;

   a cooling fluid circuit including a heat exchanger;

   a pump operable to pump the cooling fluid in the circuit from the reservoir to the heat exchanger and thence back to reservoir, whereby the frozen medium gradually melts;

   means to effect a flow of air over the heat exchanger and into the interior space; and a controller arranged to detect whether said drive is running or an ignition of the vehicle is on, and configured to preclude driving of the compressor(s) when said drive is not running or said ignition is not on.
2. 2. A vehicle comprising a sleeper cab and a drive for providing locomotive power to the vehicle, the vehicle being provided with an electrical power source, arranged to be charged by said drive, and a system for cooling an interior space for accommodating an occupant in the sleeper cab, wherein the system comprises:

   at least one refrigeration apparatus comprising a refrigeration circuit including a compressor, which is driveable by the power source, and an evaporator;

   an insulated reservoir in which the/each evaporator extends or is disposed, the reservoir holding a phase-change medium which is in heat exchange communication with the evaporator/s) whereby it can be cooled to an extent that an amount thereof freezes from a fluid or liquid state;

   a cooling fluid circuit including a heat exchanger;

   a pump operable to pump the cooling fluid in the circuit from the reservoir to the

   H:\Interwoven\NRPortbl\DCC\SBT\19327364_l.docx-19/09/2019 heat exchanger and thence back to reservoir, whereby the frozen medium gradually melts;

   means to blow air, over or via the heat exchanger, into the interior space such that the interior space is cooled; and a controller arranged to detect whether said drive is running or an ignition of the vehicle is on, and configured to preclude driving of the compressor(s) when said drive is not running or said ignition is not on.
3. 3. A vehicle according to claim 1 or 2, wherein the cooling fluid is isolated from the phase-change medium and in heat exchange communication with the phase-change medium so as to be cooled by the phase-change medium.
4. 4. A vehicle according to claim 3, wherein part of the cooling fluid circuit is arranged within the reservoir and/or the phase-change medium whereby the cooling fluid is in said heat exchange communication with the phase-change medium.
5. 5. A vehicle according to any one of the preceding claims, wherein the cooling fluid circuit includes a reservoir holding a supply of said cooling fluid, the reservoir of said cooling fluid circuit being arranged at least partially within said insulated reservoir and/or within said phase-change medium.
6. 6. A vehicle according to any one of the preceding claims, wherein the system comprises plural said refrigeration apparatuses which are operationally independent such that, where driving of the compressor of one of the apparatuses is discontinued, the compressor of the or each other apparatus can continue to operate such that the phase-change medium is cooled.
7. 7. A vehicle according to any one of the preceding claims, wherein the system comprises at least one sensor in communication with the controller and arranged to sense temperature of the phase-change medium, wherein the controller is operable to permit driving of at least one said compressor when a said sensor senses a temperature of the phase

   H:\Interwoven\NRPortbl\DCC\SBT\19327364_l.docx-19/09/2019 change medium which is less than a threshold temperature, and to preclude driving of at least one said compressor when a said sensor senses a temperature of the phase-change medium which is equal to or greater than said threshold temperature.
8. 8. A vehicle according to claim 7, wherein the system is configured such that the threshold temperature or quantity is adjustable and includes an adjustor operable to set the threshold temperature or quantity.
9. 9. A vehicle according to any one of the preceding claims, wherein the phase-change medium comprises a eutectic composition.
10. 10. A vehicle according to any one of the preceding claims, wherein the phase-change medium comprises a glycol solution.
11. 11. A vehicle according to any one of the preceding claims, wherein the system includes a thermostat arranged to detect air temperature in said space and is configured to communicate with said pump such that operation of the pump is permitted when the detected air temperature is at or above a threshold value and precluded when said air temperature is below said threshold value.
12. 12. A vehicle according to any one of the preceding claims, wherein the system includes a cooled air output unit arranged in or adjacent said interior space, the unit comprising at least one control operable to effect any one or more of:

    switching said means on and off;

    adjusting an output of said means; and adjusting said threshold value.
13. 13. A vehicle according to any one of the preceding claims, wherein the pump and said means are driveable by said power source.
14. 14. A vehicle according to any one of the preceding claims, wherein the power source comprises a battery.

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15. 15. A vehicle according to any one of the preceding claims, being a truck or truck prime mover.
16. 16. A vehicle according to any one of the preceding claims, wherein the drive comprises an engine of the vehicle.
17. 17. A vehicle according to any one of the preceding claims, wherein the evaporator of the or each refrigeration apparatus extends or is disposed in the interior of the reservoir.
18. 18. A method of establishing a source of cooling for an interior space for accommodating an occupant in a vehicle, wherein:

    the vehicle accords with any one of the preceding claims, said interior space being in said sleeper cab; and when said drive of the vehicle is running, the power source drives the compressor of at least one said refrigeration apparatus such that said medium is cooled by the evaporator of that apparatus to an extent that said amount of the medium freezes.
19. 19. A method according to claim 18, wherein said amount is the entirety of said medium.
20. 20. A vehicle according to any of claims 1 to 17, wherein:

    the sleeper cab accommodates said occupant;

    said drive is not running;

    said pump is operating to pump the cooling fluid in the circuit from the reservoir to the heat exchanger and thence back to reservoir, whereby said frozen medium gradually melts; and said means is operating such that said air is blowing or flowing over or via said heat exchanger into the interior space, whereby said interior space is cooled.