REFRIGERATION APPARATUS

TECHNICAL FIELD

The present invention relates to a refrigeration apparatus, particularly for use in environments where electrical power may be interrupted. Although the invention is primarily directed towards environments where the interruption to the power supply is out of the control of the end user, this invention may also be used to reduce the power cycle of conventional freezers in that there is no requirement for the power supply to such conventional freezers to be continuous. This may be a consumer desired requirement for "green" reasons or may be as a result of the use of these freezers at public events.

BACKGROUND ART

In some countries, primarily African and Asian countries, it is not uncommon for homes and businesses to experience frequent and intermittent interruption to the local power supply both for short periods of time and for longer periods amounting to many hours of interruption. Such power interruptions can occur at any time of the day or night. A particular problem for restaurant and bar operators is that a refrigerator filled with beverages (or other food) may only have power for a limited period of time, sometimes only three hours twice a day. Obviously, this presents a problem for keeping beverages in the refrigerator cold (in what is usually a hot country) and cooling beverage bottles/cans newly added to the refrigerator to replace those sold or consumed.

DISCLOSURE OF THE INVENTION

The present invention seeks to address the foregoing problem by providing a refrigeration apparatus for beverages comprised of a walled enclosure with an access means, further including a refrigerating means for cooling the enclosure, and a secondary cooling means.

Preferably the secondary cooling means is an ice based element or compartment. This may contain a eutectic material that will stay in a solid "ice" state for as long as possible. Most preferably, the eutectic is formulated to freeze at a temperature above zero Celsius degrees. Ideally, the eutectic material would have a melting temperature approximately equal to the optimal serving temperature of a beverage, e.g. β°C.

A eutectic material suitable for use with the invention was supplied by Phase Change Material Products Limited (www.pcmproducts . net, Yaxley, Cambridgeshire, UK) . To achieve the invention a blend of 70% E7 and 30% A4 eutectic was used.

According to the prior art, eutectic materials have been known but are usually associated with freezer environments where the melting temperature is below 0°C, often as low as -10 ⁰ C.

In one form of the refrigeration apparatus the refrigerator enclosure is in a "chest" style with a slidable door or lid providing access. In this form bottles or cans are preferably located into separate compartments (pockets) . Preferably the compartment walls are formed of a material that enables heat to transfer away from the bottle or can toward ice or another "cold mass" formed or located between the compartments. This

is in contrast to most bottle/can compartmental enclosures that usually have insulating properties in order to inhibit the flow of heat to the bottle or can and to maintain the temperature within the refrigerator. In this form the secondary cooling means is an ice mass formed by an electrically powered refrigeration circuit.

Preferably the ice mass is formed by submerging a cooling pipe lattice or coil into water, such that, as coolant passes through the pipe, heat is drawn from the water and it eventually freezes. Preferably the pipes are arranged between the bottle compartments.

In a second form the refrigeration apparatus is a standing refrigerator with a door providing the access means to the interior of the enclosure. In this form a eutectic material (freezing above 0°C) is located in, at or adjacent a wall or shelf of the refrigerator. Most ideally, a surface of the eutectic material is in contact with a beverage container.

The door is preferably transparent such that contents of the fridge can be viewed without opening the door.

BRIEF DESCRIPTION OF DRAWINGS

Figure 1 shows a plan perspective view of a refrigeration apparatus according to a preferred embodiment of the invention,

Figure 2 shows a detailed view of the embodiment from Figure 1, and

Figure 3 shows a front perspective view of a refrigeration apparatus according to a further embodiment of the invention,

MODE(S) FOR CARRYING OUT THE INVENTION

Figure 1 illustrates a preferred embodiment where the refrigeration apparatus is in the form of a chest refrigerator with top access via a sliding door 19, sliding on rails 19a.

■ This embodiment utilises a secondary cooling means and an additional feature of plural bottle pockets 20 each capable of receiving a beverage bottle B (or aluminium can) .

The walls 21 of each bottle pocket 20 are preferably formed from a suitable material such that heat from a bottle (i.e. at ambient temperature) is transferred away to improve the cooling effect provided by the primary refrigeration means (and/or secondary cooling means) . At the least, walls 21 should not substantially hinder heat transfer.

During prototype development pockets 20 were constructed from a conventional PVC downpipe which was found to be sufficient for transferring heat away from a bottle B. Generally it is preferred that the walls 21 are rigid, but a variety of diameters/depths can be provided to accommodate different package sizes.

Figure 2 illustrates further detail of the preferred embodiment, specifically providing a view below a cover 22 seen in Figure 1. It is intended that pipework 23 is submerged in a liquid medium (e.g. water) and carries a refrigerant. The pipework 23 would generally be considered the primary cooling or refrigerating means according to the invention. In practice, ice will form around pipes 23 while submerged in the water bath to eventually turn the entire body of water to solid ice, thereby creating a cold mass in between the pockets 20.

Accordingly, when electrical power is lost (and refrigerant ceases to flow through pipes 23) , the iced pipework 23 and cold water (although preferably it will be a solid ice block) surrounding pockets 20 will act as an ice bank and therefore maintain the bottles B at a sufficiently low temperature to keep a beverage refrigerated for many hours (preferably twelve hours or more) . The ice mass is effectively the secondary cooling means according to the invention.

The form of pipework arranged between the pockets directs heat removal as close as possible to the bottles/cans within the pockets 20.

In one form the water bath within which pipework 23 is submerged could be a eutectic liquid/material as will hereinafter be described.

Referring to the embodiment of Figure 3, refrigeration apparatus 10 is in the form of an upstanding refrigerator accessible via a door 11 mounted for swinging movement on a hinge 12.

In the conventional way, door 11 includes a magnetic seal 13 that holds door 11 in a closed position so that the overall enclosure 14 is isolated from ambient conditions.

Within enclosure 14 a series of racks or rails 15 are provided to hold a beverage bottle B (or aluminium can) in a convenient manner for easy accessibility by a user. Rails 15 are, in the illustrated embodiment, on a slight incline such that bottles B naturally migrate toward the front of the enclosure 14 allowing for replacement bottles (or cans) to be placed at the rear of the enclosure providing for easy access to the bottles (or

cans) at the front of the enclosure which will consequently have been within the refrigerator for the longest period of cooling.

In most respects the refrigeration apparatus 10 is of conventional design in that the walls 16 of enclosure 14 are insulated and primary refrigeration is provided by a condenser/compressor circuit with a motor powered by a mains supply.

However, not of conventional design is the provision of a secondary cooling means in accordance with the invention. In the illustrated embodiment this secondary cooling means utilises a series of compartments 17 for receiving a block of material such that it forms an "ice bank". The secondary cooling means may be a plastic skin containing a eutectic material with a melting point higher than water.

The inclusion of the secondary cooling means enables the enclosure 14 to remain at a sufficiently low temperature of around 5 degrees even if the conventional refrigeration circuit is turned off (through power failure)

The eutectic material can be chosen/developed with a melting point of, e.g. 7 ⁰ C. In other words it will phase change from a liquid to a solid state at about 7°C. In practice, materials usually begin to "freeze" at a few degrees below the melting temperature. Therefore, in a conventional refrigerator environment of approximately 4°C, the eutectic material will be guaranteed to remain in a solid state.

Ideally, the eutectic material melting temperature is approximately equivalent to the optimum serving temperature for the beverage, e.g. 6 or 7°C.

It is an established thermodynamic principle that, at a phase change, there is a large capacity for absorbing heat i.e. the energy required to achieve the phase change. Accordingly, a eutectic material with a melting point of 7°C utilised with the present invention is expected to remain in a solid state for many hours, effectively providing a cooling function to a temperature just above the normal operating temperature (4°C) of the refrigerator when the power supply is interrupted. Thus the eutectic material acts so as to both maintain the temperature of the bottles/cans already within the refrigerator and also reduces the temperature of newly added bottles/cans as product is removed.

In further forms the secondary cooling means of the invention (i.e. eutectic material) may be in direct contact with one or more bottles B within the enclosure. Specifically, a cooling mass is incorporated or built into the rack/rail arrangement of the Figure 3 embodiment. It is generally found that the invention is more effective when the secondary cooling means

(in this case a eutectic material) is in direct contact with the object to be cooled.

In another form the refrigerator enclosure may include shelves formed of or with a eutectic material. In this way a bottle or can of beverage sits on the eutectic shelf and its base is in constant contact.

Furthermore, pockets 20 of the type described in relation to the Figure 1 embodiment could be incorporated into the Figure 3 embodiment .

Test data for the described embodiments are as follows:

Figure 1 Figure 3

Embodiment Embodiment

Time for machine to chill from ambient to operating temperature 4 - 5 hours 2 h 15 min

Time for product to chill from 3O ⁰ C to 1O ⁰ C 1 h 54 min 1 h 2 min

Time for product to chill from 30 ⁰ C to 5 ⁰ C 3 h 45 min 1 h 55 min

Time for product to rise above 10 ⁰ C when machine turned off 48 hours 12 h 15 min

Time for product to rise above 5 ⁰ C when machine turned off 37 hours 4 h

Time for product to chill from 30 ⁰ C to 10 ⁰ C when machine switched off 2 h 29 min chills to 22 ⁰ C

Time for product to chill from 30 ⁰ C to 7 ⁰ C when machine turned off 4 hours

Time for product to chill from 30 ⁰ C to 6 ⁰ C when machine turned off 5 h 35 min

Time for product to chill from 30 ⁰ C to 5 ⁰ C when machine turned off

The above data is based on the use of water/ice as the cooling mass which typically remains in a frozen state at 0°C.

INDUSTRIAL APPLICABILITY

The following design considerations were made during development of the invention as a whole.

1. Suitable for use globally with priority to Sub-Sahara Africa .

2. Preferably intuitive and easy to operate.

3. Exterior to communicate branding.

4. Portability - not fixed and can be moved by 2 to 4 people.

5. Powered by intermittent electrical power supply (the worst case scenario would require the system to operate with 3 hours power twice a day) . A separate generator could be used to supplement the electricity supply.

6. An option is to be powered by a non-electrical power supply to provide flexibility of use.

7. Refrigerants used must not contaminate the water table and be selected with minimal environmental impact in mind and capable of being safely and easily removed at the end of the unit's life (No HFC's and CFCs) . 8. Detachable mains adaptor included. Must suit power supplies of 100-260V, 50-6Hz input.

9. Compatible with the use of block or flake ice.

10. Unit working life expectancy greater than three years.

11. To have capacity to nominally hold 48 bottles/cans. The system will need to handle bottles ranging in size from

33OmL to 60OmL. (Up to 54 bottles will need cooling on a week night and 90 at the weekend during a typical session of 3 hours. N. B. these figures are a guide only as there will be significant variation from outlet to outlet) . 12. Ability to cool from ambient (max. 35 centigrade) through to 4 or 5 degrees centigrade in 30-90 minutes. Humidity of 70% maximum.

13. Thermal insulation to maintain temperature between 4 and 15 centigrade for 3 hours if the power source is lost. (This is key during the serving period when the product is constantly being removed from the cooler) .

The present invention is able to be manufactured from available materials and provides a cost effective solution to the problem of unreliable power supplies in many countries