BACKGROUND

This invention relates to a power supply and more particularly a power supply for an apparatus comprising a heat exchanger and an associated method of supplying power to an apparatus comprising a heat exchanger. An example of an apparatus comprising a heat exchanger is a cold storage device. It is known to use rechargeable batteries in association with some cold storage devices, especially in association with portable cold storage devices. The rechargeable batteries are charged by an external power source, typically a mains AC power source, which, in use, normally also provides power to relevant parts of a refrigerator system of the cold storage device. In use, the rechargeable batteries provide back up power to the refrigeration system, when the external power source is not available. A disadvantage of the above known cold storage devices is that they are not as energy efficient as would be desired in some applications. This is attributed to, amongst others, thermal losses associated with the heat exchanger.

OBJECT OF INVENTION

Accordingly, it is an object of the present invention to provide a power supply for an apparatus comprising a heat exchanger and an associated method with which I believe the aforementioned disadvantages may at least be alleviated or which may provide useful alternatives for the known apparatus and methods.

SUMMARY OF THE INVENTION

According to the invention there is provided a power supply for an apparatus comprising heat exchanger, the power supply comprising:

- a battery arrangement comprising at least one rechargeable battery; and

- a thermoelectric generator arrangement having an electrical output, the thermoelectric generator arrangement being mounted at the heat exchanger to utilise a temperature differential to generate at the electrical output, an output voltage, the electrical output being connected to the battery arrangement via a first electronic circuit to utilise the output voltage to charge the rechargeable battery.

The thermoelectric generator arrangement may comprise one thermo electric generator module. Alternatively, the thermoelectric generator arrangement may comprise a plurality of thermoelectric generator modules. The plurality of thermoelectric generator modules may be electrically connected to one another in at least one of a series and parallel configuration. The first electronic circuit may comprise a boost regulator. The power supply may further comprise an alternating current supply connector connected to the rechargeable battery via a second electronic circuit. The second electronic circuit may comprise a transformer and a rectifier circuit. The battery arrangement may be electrically connected to an electrical load forming part of the apparatus. The apparatus may comprise a cold storage device, such as a portable fridge/freezer. The electrical load may comprise at least a first electrical motor for driving a compressor and a second electrical module of motors for driving an air moving devices, such as a micro heat extractor fans, mounted at the thermoelectric generator cold side module. According to another aspect of the invention there is provided a method of supplying power to a rechargeable battery arrangement of an apparatus comprising a heat exchanger, the method comprising the steps of:

- utilising a thermoelectric generator arrangement in association with the heat exchanger, to generate an output voltage; and

- utilising the output voltage to charge the rechargeable battery. BRIEF DESCRIPTION OF DRAWINGS

The invention will now further be described, by way of example only, with reference to the accompanying drawings wherein: figure 1. is a diagrammatic perspective view of an example embodiment of a cold storage apparatus, in the form of a portable fridge/ freezer, comprising a heat exchanger; and figure 2. is a block diagram of an example embodiment of a power supply for the apparatus.

DESCRIPTION OF EMBODIMENTS

An example embodiment of a power supply 10 for an apparatus 12 comprising a heat exchanger 14 is shown in figure 1 and 2. The apparatus may be in the form of a cold storage device, such as a portable fridge/ freezer. Referring to figure 1 , the power supply 10 comprises a battery arrangement 16 comprising at least one rechargeable battery and a thermoelectric generator arrangement 18. The thermoelectric generator 18 comprises thermoelectric generator modules 18.1 to 18.n. The thermoelectric generator arrangement 18 has an electrical output 20.

The thermoelectric generator arrangement 18 mounted at the heat exchanger 14 to utilise a temperature differential to generate an output voltage at an electric output 20. The electrical output 20 is electrically connected to the rechargeable battery arrangement 16 via a boost regulator 22. The boost regulator 22 ensures that a voltage supplied to the rechargeable battery arrangement 16 remains within predetermined limits, in order to effectively charge the rechargeable battery arrangement 16.

The power supply 10 further comprises an alternating current (AC) supply connector 24 connected to the rechargeable battery arrangement 16 via a second electric circuit comprising a transformer 26 and a rectifier circuit 28. The portable fridge/freezer 12 comprise a body 30 which encloses a space 32 to be cooled, a refrigeration system 34 and the power supply 10 comprising the rechargeable battery arrangement 16. The power supply 10 supplies electrical power to relevant parts of the refrigeration system

34, as a load 35. The refrigeration system 34 comprises a compressor 36, the heat exchanger 14, an air moving device 38 associated with the heat exchanger 14, an expansion valve 40 and piping 42. The piping 42 has a first end 44 and second end 46. In use, and during a first refrigeration cycle, a refrigeration fluid (not shown) is pressurised by the compressor 36 and cooled down firstly by the heat exchanger 14 and secondly the expansion valve 40. The cooled down refrigeration fluid is then introduced to the piping 42 at the first end 44. The piping 42 is arranged to be in thermal communication with the space 32. Hence, as the cooled down refrigeration fluid moves from the first end 44 to the second end 46, an ambient temperature within the space 32 is reduced. The reduction of temperature within the space 32, is a result of thermal energy transfer from the space 32 to the piping 42. Therefore, as the ambient temperature of the space 32 is reduced, the temperature of the refrigeration fluid in the piping 42 is increased and the pressure thereof is reduced. During a second refrigeration cycle, the refrigeration liquid received from the second end is pressurised and cooled down again before being reintroduced at the first end 44. The load 35 comprises compressor 36 which is mechanically driven by a first electrical motor (not shown).

The air moving devices 38, typically a micro heat extractor fans, is mechanically driven by a second electrical motors (not shown). The first and second electrical motors are electrically connected to the power supply 10. Figure 2 is a diagrammatic representation of the power supply 10. The thermoelectric generator arrangement 18 comprises the thermoelectric generator 18.1 to 18.n. Thermoelectric modules 18.1 to

18.3 are electrically connected in a suitable series and/or parallel configuration.