WO2004104499A1

WO2004104499A1 - Transportable refrigeration apparatus

Info

Publication number: WO2004104499A1
Application number: PCT/AU2004/000673
Authority: WO
Inventors: Tony Richard Boyd; Peter John Mckay
Original assignee: Refrigeration Research Pty Ltd
Priority date: 2003-05-21
Filing date: 2004-05-21
Publication date: 2004-12-02
Also published as: AU2003902469A0

Abstract

A transportable refrigeration apparatus for refrigerating a separable open topped bin is disclosed. The apparatus comprises: an upper body (25) releasably mountable to the open topped bin (10); an evaporator (50) mounted to the upper body (25) and shaped to define an inner space (58) and an outer surface (55), in use the evaporator (50) extending into the bin; a compressor and motor assembly (44) located within the inner space (58); and a condenser mounted to the upper body, the condenser, the compressor and evaporator (50) forming parts of a refrigeration circuit. A battery is mounted to the upper body (25) and within the inner space (58) and a control system controls supply of power to the compressor motor from alternative power sources including battery. The controller includes a DC to AC inverter. In use, the refrigeration circuit extracts heat through the outer surface of the evaporator (50) from the bin (10) during its transportation to maintain the contents of the bin at a temperature below ambient temperature for an extended period of time.

Description

TRANSPORTABLE REFRIGERATION APPARATUS

FIELD OF THE INVENTION

The present invention relates to transportable /portable refrigeration units and in particular to self-powered refrigeration units for commercially shipping produce.

BACKGROUND

Transportable and portable refrigeration units are currently available in a wide variety of forms. For instance, large refrigerated containers, including ISO containers, utilising conventional mechanical refrigeration plants are known.

Smaller domestic vehicle refrigerators that are capable of operating from the vehicle's 12 volt power supply are also known.

The applicant has identified a need for an improved method and apparatus for providing a "cold chain" for high value produce including seafoods that require transportation in pallet-sized quantities. There is a need to transport such produce over long distances between regions of production or harvest and the markets for the produce.

It is an object of the invention to provide a transportable refrigeration apparatus capable of powering itself and maintaining produce at a temperature below ambient temperature for an extended period.

It is a further object of the invention to provide a method and apparatus that can be transported to a destination and then returned at minimum cost.

SUMMARY OF THE INVENTION

According to a first aspect of the invention there is provided a transportable refrigeration apparatus for refrigerating a separable open topped bin, the apparatus comprising: an upper body releasably mountable to the open topped bin; an evaporator mounted to the upper body and shaped to define an inner space and an outer surface, in use the evaporator extending into the bin; a compressor and motor assembly located within the inner space; a condenser mounted to the upper body , the condenser, the compressor and evaporator forming parts of a refrigeration circuit; a power storage means mounted to the upper body and within the inner space; and a control system for controlling supply of power to the compressor motor from alternative power sources including the power storage means, the controller including a DC to AC inverter, wherein, in use, the refrigeration circuit extracts heat through the outer surface of the evaporator from the bin during its transportation to maintain the contents of the bin at a temperature below ambient temperature for an extended period of time.

Preferably the inverter is a sine wave inverter.

Various types of sine wave inverters, including modified sine wave and true sine wave inverters may be used, however, preferably the sine wave inverter is a true sine wave inverter.

Preferably the upper body comprises: a refrigeration module; and an lid module, the lid module hingedly connected to the refrigeration module, wherein the lid module is rotatable with respect to the refrigeration module to provide convenient access to the bin.

Preferably the evaporator comprises a thermally conductive outer shell defining the outer surface and having refrigerant piping on an inner surface for heat absorption from the outer shell.

Preferably the apparatus further comprises an insulating layer within the inner space adjacent the inner surface.

The insulating layer may simply be air or a partial vacuum. Preferably the insulating layer includes an insulating material.

Preferably the apparatus further comprises a liner, the liner within the inner space and adjacent the insulating layer, wherein the liner protects the insulating layer.

Preferably the power storage means comprises at least one rechargeable battery.

Preferably the control system monitors controls the AC power delivery to the motor so as to keep the DC current draw below a preset amount, thereby extending the life of the rechargeable battery or batteries.

According to a second aspect of the invention there is provided a transportable refrigeration assembly comprising: an open topped bin: an upper body releasably mountable to the open topped bin; an evaporator mounted to the upper body and shaped to define an inner space and an outer surface, in use the evaporator extending into the bin; a compressor and motor assembly located within the inner space; a condenser mounted to the upper body , the condenser, the compressor and evaporator forming parts of a refrigeration circuit; a power storage means mounted to the upper body and within the inner space; and a control system for controlling supply of power to the compressor motor from alternative power sources including the power storage means, the controller including a DC to AC sine wave inverter, wherein, in use, the refrigeration circuit extracts heat through the outer surface of the evaporator from the bin during its transportation to maintain the contents of the bin at a temperature below ambient temperature for an extended period of time.

Preferably the assembly further comprises an insulating layer within the inner space and adjacent the inner surface.

Preferably the assembly further comprises a liner, the liner within the inner space adjacent the insulating layer, wherein the liner protects the insulating layer.

Preferably the power storage means comprises at least one rechargeable battery.

Preferably the control system monitors controls the AC power delivery to the motor so as to keep the DC current draw below a preset amount, thereby extending the life of the rechargeable battery or batteries. Preferably the upper body has a top surface shaped to receive a bottom surface of the bin such that a plurality of transportable refrigeration assemblies are stackable.

Preferably the top surfaces and bottom surfaces are mutually shaped so as to allow outside air to pass through the condenser so that the refrigeration circuit is operable while a plurality of transportable refrigeration assemblies are stacked.

According to a third aspect of the invention there is provided a method, the method comprising the steps of: providing an insulated container or bin, the container having an open top; loading goods into the container at a first location; providing a transportable refrigeration assembly having a body adapted for attachment to the open top of the container, the refrigeration assembly having a power storage means and protruding evaporator; attaching the refrigeration assembly to the open top of the container; transporting the container and assembly to a second location, the second location remote from the first location; removing the assembly from the container; and returning the assembly to the first location.

Preferably the method further comprises the controlling of power delivery to a motor driving a compressor that forms part of a refrigeration circuit with the evaporator so as to keep the DC current drawn below a preset amount thereby optimising the time during which refrigeration can be continued before exhausting the power storage means.

Preferably the controller monitors controls the AC power delivery to the motor so as to keep the DC current draw below a preset amount. This is achieved by controlling the frequency and /or pulse width and /or peak voltage delivery. Various open topped bins may be used. For instance bins constructed from high density polyethylene with high density urethane insulation may be used. Bins having a completely open top are easily loaded, but bins having smaller apertures forming an opening for access may also be used. Desirably the bins and their releasably mounted refrigeration assemblies are produced so as to be stackable.

The 'inside out' configuration of the evaporator not only provides a large surface area for thermal efficiency, it also provides an inner space for housing the refrigeration components so that they do not protrude upwards. This allows the top of the body that is releasably mounted to the top of the bin to be free of substantial protrusions so that the refrigeration assemblies can be readily stacked.

A specific embodiment of the invention will now be described in some further detail with reference to and as illustrated in the accompanying figures. This embodiment is illustrative, and is not meant to be restrictive of the scope of the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT OF THE INVENTION A preferred embodiment of the invention is illustrated in the accompanying representations in which:

Figures 1 and 2 are perspective views of a transportable refrigeration assembly attached to an open top bin.

Figures 3 and 4 are diagrammatic sectional views of the refrigeration assembly and bin shown in Figures 1 and 2.

Figure 5 is a schematic perspective view of components within the refrigeration assembly shown in Figures 1 to 4. Figure 6 is a diagrammatic perspective view of an evaporator, the evaporator being a component of the refrigeration assembly of Figures 1 to 4.

Referring to Figure 1, a transportable refrigeration assembly 20 according to a first aspect of the invention is shown. The refrigeration assembly 20 is releasably mountable to an open top bin 50. Elastic ties 36, 37, 38 and 39 (only ties 36 and 37 are shown in Figure 1) are used to releasably secure the refrigeration assembly to the bin 50.

Referring to Figure 2, a pliant seal 32 is provided to prevent air being transferred into or out of the bin 50. The bin 50 is made from high density polyethylene or polypropylene to provide clean, safe, food quality storage. Referring to Figures 3 and 4, high density urethane insulation 12 is shown. This construction minimises heat gain from the surrounding environment thereby keeping produce within the bin 50 fresher longer. A large drain (not illustrated) is provided to assist cleaning. Fork lift tyne recesses 15 are provided to facilitate handling.

The refrigeration assembly 20 has foot receiving pads 34, shown in Figure 1, for receiving feet 14 of bins 10 allowing stackability.

Again referring to Figure 1, the refrigeration assembly comprises a body 25, an evaporator 50 mounted to the body and shaped to define an interior cavity 58 as shown in Figure 6. Referring to Figure 6, the evaporator 50 comprises an outer shell 54 having tubing 52 welded to it. The evaporator shell 54 has an outer surface 55 which, in use, extends into the bin 50.

The cavity 58, defined by the evaporator 50, surrounds a housing 42 containing refrigeration and power components as is illustrated in Figure 5. Referring to Figure 5, it can be seen that the compressor and motor assembly 44 and battery 60 and 62 are disposed within the housing 42, which is itself disposed within the cavity 58. This arrangement, made possible by the "inside out" design of the evaporator 55, allows for a very compact overall assembly while maintaining a large evaporator outer surface area 55. The large outer surface of the evaporator 55 promotes high heat transfer for efficient extraction of heat from within the bin 50.

Referring again to Figures 1 and 2, it can be seen that the refrigeration assembly 20 has a body 25 comprising two modules, a refrigeration module 40 and a openable cover module 30. The cover module 30 is connected to the refrigeration module 40 by three hinges 22 as is illustrated in Figure 1. This allows the cover module 30 to be rotated with respect to the refrigeration module 40 to provide access to the inside of the bin 50. Figure 2 shows the cover module 30 rotated upwards providing access to the inside of the bin 50. The components of the refrigeration circuit, other than the evaporator 50 are best shown in Figure 5. A conventional vapour compression refrigeration cycle is used. Components of the refrigeration circuit include a compressor and motor assembly 44, a condenser 46, an expansion valve (not shown) and the evaporator 50. A condenser fan assembly 48 containing two fans is provided. These fans draw air in through air inlet grill 45, through the condenser 46 and then out through air outlet grill 47.

Power is provided to the compressor and motor assembly 44 from a number of alternative sources. Where no external power is available, power is provided from an internal power storage means in the form of twin spiral cell batteries 60 and 62. The batteries 60 and 62 are connected to a power outlet 64. DC power inlet 66 plugs into outlet 64 where no external DC power is available. Power travels from DC power inlet 66 through inverter 70 to the compressor motor 44. The compressor motor 44 is a conventional two pole induction motor with start and run windings and normal relay start function. The inverter converts the DC current to a AC. A control system including a microprocessor and a DC to AC sine wave inverter power supply unit 70 is provided for operation of the refrigeration circuit from batteries 60 and 62 or from external DC power sources.

The inverter unit 70 will accept DC input from 10VDC to 40VDC and deliver 240 VAC at a nominal frequency of 50 cycles per second.

The processor will also monitor the DC current rate and cause the frequency and or pulse width and or peak voltage to vary to maintain a DC current rate lower than a preset amount. (This preset value can be accessed discretely via the touch pad of the remote controller 72 as shown in Figure 5.)

The application of this limiting factor also allows the compressor to "soft start" with start up current also limited during the start period.

The compressor motor (although a conventional two pole induction motor with start/run windings and normal relay start function) will have both windings supplied direct from the power supply unit 70 where the processor will cause each winding to be supplied appropriately, to allow functioning within the parameters as described above. This ability addresses the many problems associated with powering induction motors from such a restricted power source.

Other controls of the motor include digital thermostat switching, low voltage programmed shut down and various system protection.

The power supply unit also supplies a small DC condenser fan assembly 48 on the following basis: Fan assembly 48 is supplied with full DC supply while hysteresis (required cabinet temp and ambient temp) is 30°C or greater reducing to allow 50% speed when hysteresis lowers to 15°C. The overall design of the refrigeration assembly 20 allows for optimum cooling from finite DC storage batteries 60 and 62 thereby maintaining the contents of the bin 50 at a low temperature for an extended period of time.

Where external AC power is available, plug 68 is connected to the external power source to supply the compressor motor 44. Recharge of the batteries 60 and 62 occurs automatically. When external AC power is disconnected, or a "brown out" occurs, the refrigeration assembly will pause for 10 minutes and then will resume operating from its own power supply.

An important feature of the refrigeration assembly 20 described above is its separability from the bin or container 10. Containers are relatively bulky and can be costly to transport, especially by air freight. In some applications it will be cost effective to only return the refrigeration assembly 20 after delivery of refrigerated produce to its destination.

The separability of the bin 10 from the refrigeration assembly 20 also allows bins of differing depths and hence capacities to be used with the same refrigeration assemblies 20.

The transportable refrigeration assembly 20 will have many applications due to its ability to operate from both a variety of external power sources, including "mains" AC power and vehicle 12 volt DC power, and internal batteries. Its intelligent control system allows extended refrigerated transport in stand alone mode.

While the present invention has been described in terms of a preferred embodiment in order to facilitate better understanding of the invention, it should be appreciated that various modifications can be made without departing from the principles of the invention. Therefor, the invention should be understood to include all such modifications within its scope.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. A transportable refrigeration apparatus for refrigerating a separable open topped bin, the apparatus comprising: an upper body releasably mountable to the open topped bin; an evaporator mounted to the upper body and shaped to define an inner space and an outer surface, in use the evaporator extending into the bin; a compressor and motor assembly located within the inner space; a condenser mounted to the upper body , the condenser, the compressor and evaporator forming parts of a refrigeration circuit; a power storage means mounted to the upper body and within the inner space; and a control system for controlling supply of power to the compressor motor from alternative power sources including the power storage means, the controller including a DC to AC inverter, wherein, in use, the refrigeration circuit extracts heat through the outer surface of the evaporator from the bin during its transportation to maintain the contents of the bin at a temperature below ambient temperature for an extended period of time.

2. An apparatus as claimed 1 where the inverter is a sine wave inverter.

3. An apparatus as claimed in claim 1 or 2 wherein the upper body comprises: a refrigeration module; and an lid module, the lid module hingedly connected to the refrigeration module, wherein the lid module is rotatable with respect to the refrigeration module to provide convenient access to the bin.

4. An apparatus as claimed in any one of claims 1 to 3 wherein the evaporator comprises a thermally conductive outer shell defining the outer surface and having refrigerant piping on an inner surface for heat absorption from the outer shell.

5. An apparatus as claimed in claim 4 further comprising an insulating layer within the inner space adjacent the inner surface.

6. An apparatus as claimed in claim 5 further comprising a liner, the liner within the inner space and adjacent the insulating layer, wherein the liner protects the insulating layer.

7. An apparatus as claimed in claim 6 wherein the power storage means comprises at least one rechargeable battery.

8. An apparatus as claimed in claim 7 wherein the control system monitors controls the AC power delivery to the motor so as to keep the DC current draw below a preset amount, thereby extending the life of the rechargeable battery or batteries.

9. A transportable refrigeration assembly comprising: an open topped bin: an upper body releasably mountable to the open topped bin; an evaporator mounted to the upper body and shaped to define an inner space and an outer surface, in use the evaporator extending into the bin; a compressor and motor assembly located within the inner space; a condenser mounted to the upper body , the condenser, the compressor and evaporator forming parts of a refrigeration circuit; a power storage means mounted to the upper body and within the inner space; and a control system for controlling supply of power to the compressor motor from alternative power sources including the power storage means, the controller including a DC to AC sine wave inverter, wherein, in use, the refrigeration circuit extracts heat through the outer surface of the evaporator from the bin during its transportation to maintain the contents of the bin at a temperature below ambient temperature for an extended period of time.

10. An assembly as claimed in claim 9 wherein the upper body comprises: a refrigeration module; and an lid module, the lid module hingedly connected to the refrigeration module, wherein the lid module is rotatable with respect to the refrigeration module to provide convenient access to the bin.

11. An assembly as claimed in either one of claims 9 or 10 wherein the evaporator comprises a thermally conductive outer shell defining the outer surface and having refrigerant piping on an inner surface for heat absorption from the outer shell.

12. An assembly as claimed in claim 11 further comprising an insulating layer within the inner space and adjacent the inner surface.

13. An assembly as claimed in claim 12 further comprising a liner, the liner within the inner space adjacent the insulating layer, wherein the liner protects the insulating layer.

14. An assembly as claimed in claim 13 wherein the power storage means comprises at least one rechargeable battery.

15. An assembly as claimed in claim 14 wherein the control system monitors controls the AC power delivery to the motor so as to keep the DC current draw below a preset amount, thereby extending the life of the rechargeable battery or batteries.

16. An assembly as claimed in any one of claim 9 to 15 wherein the upper body has a top surface shaped to receive a bottom surface of the bin such that a plurality of transportable refrigeration assemblies are stackable.

17. An assembly as claimed in claim 16 wherein the top surfaces and bottom surfaces are mutually shaped so as to allow outside air to pass through the condenser so that the refrigeration circuit is operable while a plurality of transportable refrigeration assemblies are stacked.

18. A method of transporting goods in a refrigerated condition, the method comprising the steps of: providing an insulated container or bin, the container having an open top; loading goods into the container at a first location; providing a transportable refrigeration assembly having a body adapted for attachment to the open top of the container, the refrigeration assembly having a power storage means and protruding evaporator; attaching the refrigeration assembly to the open top of the container; transporting the container and assembly to a second location, the second location remote from the first location; removing the assembly from the container; and returning the assembly to the first location.

19. A method as claimed in the preceding claim further comprising the controlling of power delivery to a motor driving a compressor that forms part of a refrigeration circuit with the evaporator so as to keep the DC current drawn below a preset amount thereby optimising the time during which refrigeration can be continued before exhausting the power storage means.

20. A transportable refrigeration apparatus substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

21. A transportable refrigeration assembly substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.