Abstract:
The present invention relates to improvements in or relating to cooling, in particular for cooling beverages in containers such as cans or bottles. We describe a cooling apparatus having a cavity for receipt of a product to be cooled; rotation means to rotate a product received in the cavity and cooling liquid supply means to provide a cooling liquid to the cavity. The rotation means is adapted to rotate the product at a rotational speed of 90 revolutions per minute or more and is also adapted to provide a pulsed or non-continuous rotation for a predetermined period.

Description:
BACKGROUND 
       [0001]    The present invention relates to improvements in or relating to cooling. 
         [0002]    In catering, retail and entertainment sectors, various forms of vending devices are used in order to keep products chilled. For cold beverages these devices form two typical groups—commercial drinks refrigerators and cold beverage vending machines. Both types of device are essentially large glass-fronted refrigerators having hinged or sliding doors in the case of the first group (for manual dispensing) or a dispensing mechanism in the case of the second. They pre-cool and store drinks ready for purchase. In many cases, the drinks are maintained at low temperatures for long periods before they are eventually purchased. As a result, considerable energy is used, potentially unnecessarily. Compounding the problem, both types of device operate inefficiently. In use, drinks refrigerators of the first group suffer substantial loss of cold air every time the large door is opened. Vending machines must provide easy passage to the vending tray where the item is collected by the user, resulting in poor sealing. Refrigeration systems generally have a requirement to be exercised through background running cycles to maintain efficiency, but this uses additional energy not directly contributing to chilling the contents. 
         [0003]    It is also known for many beverage retailers to stock beverages in open-fronted refrigerated cabinets for ease of access and visibility of product. These cabinets obviously suffer even greater energy wastage. 
         [0004]    The net result is high levels of wasted electrical energy used in keeping drinks in a long-term cold state in readiness for purchasing, regardless of whenever that might occur. 
         [0005]    Energy wastage is not confined to corporate sites hosting vending machines. Many small corner shops, petrol stations and café outlets host drinks chilling cabinets. For these operators, electrical energy costs will represent a high proportion of their operational overhead. Energy wastage is not the only issue. Since refrigeration systems generate heat, often the wasted heat energy by-product from the refrigeration system causes unwanted warming of the localised area around the machines. This creates an inconsistency in which users must drink their satisfactorily chilled drinks in unsatisfactorily warm areas. 
         [0006]    Speed of cooling is also an issue, particularly in establishments having a high turnover of beverages, such as at special events—concerts, sporting eventings and so on. Often, at the start of the event, drinks are adequately cooled by having been refrigerated for several hours. However, once the event is under way, the volume of drinks being sold exceeds the capacity of the refrigerators to chill further drinks Drinks must then be sold only partially chilled or not chilled at all. 
         [0007]    The present invention seeks to address these problems by providing an apparatus that allows cooling of beverages on demand. The apparatus can be a stand-alone device or may be incorporated into a vending machine. 
       BRIEF DESCRIPTION 
       [0008]    The present invention provides a cooling apparatus comprising a cavity for receipt of a product to be cooled. The apparatus comprises rotation means to rotate a product received in the cavity and cooling liquid supply means to provide a cooling liquid to the cavity. The rotation means is adapted to rotate the product at a rotational speed of 90 revolutions per minute or more and is further adapted to provide a pulsed or non-continuous rotation for a predetermined period. 
         [0009]    Preferably, the rotation means is adapted to rotate the product at least about 180 revolutions per minute, more preferably at least about 360 revolutions per minute. 
         [0010]    Preferably, the cooling fluid supply means is adapted to provide a flow of cooling liquid to the cavity. 
         [0011]    Preferably, the cooling liquid is supplied to the cavity at a temperature of −10° C. or less, more preferably −14° C. or less, even more preferably −16° C. or less. 
         [0012]    A cooling apparatus as claimed in any one of claims  1  to  4  wherein the rotation means is adapted to rotate the product about an axis of the product and further comprises retaining means to prevent or substantially avoid axial movement of the product during rotation. 
         [0013]    A cooling apparatus as claimed in any one of claims  1  to  5  wherein the rotation means is adapted to rotate the product for at least one cycle of: rotation for a predetermined rotation period and non-rotation for a predetermined pause period; followed by a further predetermined period of rotation. 
         [0014]    A cooling apparatus as claimed in claim  6  wherein the rotation means performs at least two cycles, preferably three to six cycles, more preferably three or four cycles. 
         [0015]    A cooling apparatus as claimed in claim  6  or claim  7  wherein the predetermined rotation period is 5 to 60 seconds, preferably 5 to 30 seconds, more preferably 5 to 15 seconds, most preferably about 10 seconds. 
         [0016]    A cooling apparatus as claimed in claim  8  wherein the predetermined pause period is 10 to 60 seconds, preferably 10 to 30 seconds. 
         [0017]    In certain embodiments, the apparatus comprises a plurality of cavities as defined above. 
         [0018]    In typical embodiments, the apparatus is incorporated in a vending apparatus and the vending apparatus further comprises insertion and removal means for inserting the product to be cooled into the cavity and removing the cooled product therefrom. 
         [0019]    Preferably, the vending apparatus further comprises storage means for storing a product or range of products and selection means for selecting a product from the storage means for insertion into the cavity. 
         [0020]    The above and other aspects of the present invention will now be described in further detail, by way of example only. 
         [0021]      FIGS. 1 to 4  graphically show the results of cooling trials with a first embodiment of an apparatus in accordance with the present invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0022]      FIG. 1  is a chart of test results examining the effect of the speed of rotation on the cooling of a container; 
           [0023]      FIG. 2  is a chart of test results comparing continuous rotation and intermittent rotation of a container on cooling results; 
           [0024]      FIG. 3  is a chart of test results comparing different intermittent rotation rpms and number of spins on cooling results; and 
           [0025]      FIG. 4  is a chart comparing temperature versus time showing the average results of a larger series of trials. 
       
    
    
     DETAILED DESCRIPTION 
       [0026]    In discussing the present invention, a brief review of current methods for selectively cooling beverages on a container-by-container basis will be helpful. A typical 330 ml aluminium can containing a beverage can be cooled in a refrigerator set at a typical operating temperature of around 4 to 5° C. from an ambient temperature of 25° C. to a comfortable drinking temperature of 6° C. in approximately four hours or so. In a freezer, the period is reduced to around 50 minutes. 
         [0027]    Peltier coolers are available and are based on the physics of the Peltier effect, which occurs when a current is passed through two dissimilar metals coupled in a face-to-face arrangement. One of the metals will heat up and the other will cool down. The cold side in contact with the cooling chamber of the can reduces the can temperature. 
         [0028]    Peltier coolers are already extremely popular in high-end computer cooling systems and scientific CCD imaging systems. They have been applied to portable cool boxes and in-vehicle refrigerators, where a compressor would be too noisy or bulky. A cooling cycle time for a standard can is in excess of 30 to 45 minutes. In addition, because the Peltier element is typically located adjacent the concave base of the can, the can is cooled very unevenly. As a result these devices are only really suitable for maintaining the temperature of a pre-chilled drink 
         [0029]    Gel-based cooling jackets, may, depending on their size, cool a can or bottle in under 15 minutes. These work by encapsulating a high concentration of sodium-based phase-change material into a sleeve, designed to fit closely around the can. This sleeve must then be cooled in a freezer and then re-cooled after each use. 
         [0030]    The current state of the art methodology for cooling bottles and cans is considered to be the Cooper cooler. The unit slowly rotates a beverage container horizontally, whilst covering or immersing the container in ice-cold water. From a 25° C. starting temperature a bottle may be cooled to 11° C. in 3.5 minutes and to 6° C. in 6 minutes. In addition, the unit requires a substantial supply of ice cubes to chill adequately. This technology is not sufficiently fast for commercial applications, it requires a large number of ice cubes and results in damage to the branding labels on the bottle. 
         [0031]    Within a carbonated drink, carbon dioxide is dissolved in the liquid under pressure (Henry&#39;s Law). When the pressure is reduced (upon opening), the liquid becomes less capable of holding carbon dioxide (CO 2 ), and so the CO 2  will come out of solution. All carbonated drinks therefore effervesce (fizz) upon opening as the internal pressure of their container is reduced. Whether they fizz over (liquid comes out of the container explosively) depends on how quickly CO 2  comes out of solution. Effervescence is enhanced by the availability of nucleation sites in the container which act as foci for the formation of bubbles. 
         [0032]    We have determined that a carbonated drink will not effervesce excessively up when rotated at high speeds because nucleation does not occur. In comparison, when a carbonated drink is shaken, the air pocket above the beverage is broken up into a large number of small pockets dispersed throughout the beverage which then act as nucleation sites when the can is opened. The CO 2  then expands rapidly, carrying the liquid out of the can. However, when a beverage is only rotated, the air pocket stays substantially intact. There are few, if any, nucleation sites dispersed throughout the liquid, and the slow decarbonation takes place. 
         [0033]    We have developed an apparatus comprising a cavity for receipt of a can or other container for a beverage to be cooled. The cavity includes a motor-driven turntable to allow the can to be rotated at speed and also includes a clamp to hold the can in position on the turntable whilst permitting rotation. The apparatus also includes supply means for a cooling liquid. 
         [0034]    In its crudest form, the cooling liquid is simply poured into the cavity and then removed at the end of the cooling process. In preferred embodiments, a flow of cooling liquid through the apparatus is provided. 
         [0035]    In trials, we investigated the effects of spray cooling and liquid flow cooling on a can surface. These trials showed that liquid flow cooling provided better results. Spray cooling technology did not efficiently cool the central point of the can, providing only the external impression of a cold can but not a sufficiently cooled drink. 
         [0036]    We then conducted a series of trials investigating the optimal methodology of agitating a can at different speeds seeking to avoid fizzing. These experiments showed that a can may be rotated at 360 rpm for over 5 minutes without fizzing. Axial agitation motions resulted on a non even mix or violent fizzing actions. 
         [0037]    To further develop the concept, a sealed can cooling rig was manufactured to use a salt water solution which is chilled down to approximately −16° C., in a cooling tank with a rotating agitator to reduce salt solidification. A diaphragm pump was used to fill the cooling vessel, at a rate of up to 5 litres/min The cooling vessel has been designed to accept a standard can, which may be rotated up to 12 Hz/720 rpm. The flow rate of the pump and rotational speed of the can are controllable. The real-time cooling rates of the drink were recorded. 
         [0038]    We have determined that, during rotation of a can, a forced vortex develops, the depth of which inside the can is dependent upon the speed of rotation. Forced convection takes place and creates artificially-induced convection currents inside the can. When the rotation is then stopped, a free or collapsing vortex forms and natural convection takes place, promoting mixing of the contents of the can but without incorporation of air bubbles which might lead to nucleation and excessive effervescing. 
         [0039]    However, in a static can without this collapsing vortex, cooler beverages being denser, sinks to the base of the can. Mixing of the can contents is very poor leading to poor thermal uniformity, and also leading, in many cases, to ice formation or “slushing”. 
         [0040]    We conducted a range of trials to assess the success of various rotational speeds in producing a uniformly cooled beverage. The following experiments help illustrate the invention. 
         [0041]    Comparative Test 
         [0042]    Initially, we conducted a trial without any rotational agitation of the can. The results are shown in Table 1. 
         [0000]    
       
         
               
               
               
               
               
               
               
               
             
           
               
                 TABLE 1 
               
               
                   
               
               
                   
                   
                 Tank 
                 Tank 
                 Temp 
                 Temp 
                   
                   
               
               
                 Cooling 
                 Number 
                 start 
                 end 
                 Can 
                 Can 
                 Temp 
                 Average 
               
               
                 time 
                 of spin 
                 temp 
                 temp 
                 base 
                 middle 
                 Can top 
                 Temp 
               
               
                 (sec) 
                 cycles 
                 (° C.) 
                 (° C.) 
                 (° C.) 
                 (° C.) 
                 (° C.) 
                 (° C.) 
               
               
                   
               
             
             
               
                 60 
                 0 
                 −17 
                 −16 
                 5 
                 18 
                 20 
                 14.3 
               
               
                   
               
             
          
         
       
     
         [0043]    As can be seen, from an ambient temperature of 20-22° C. The contents of the base of the can are satisfactorily cooled to a desirable temperature, but there is minimal cooling of the top of the can, giving a wide temperature range throughout the can and poor average cooling. 
         [0044]    Experimental Tests 
         [0045]    In the first group of tests, we sought to examine the effect of the speed of rotation on the cooling results. The results are shown in  FIG. 1  in which the temperature scale represents the average temperature of the contents of the can. It will be seen that improved results are obtained at higher rotation speeds, with more rapid cooling being achieved at 360 rpm (Test 3) compared with at 180 rpm (Test 2) or at 90 rpm (Test 1). In these trials, it was noted that, as would be expected, pre-chilling of the cooler cavity had a substantial effect on successful chilling of the can contents. It was also noted that, at 180 rpm, there remained a 6° C. difference between the temperatures at the top and the base of the can. 
         [0046]    We then set out to investigate whether intermittent rotation had a better effect on cooling than continuous rotation. It will be appreciated that intermittent rotation allows the vortex to collapse several times during the cooling process and so might be expected to promote more even temperature distribution. The results are shown in  FIG. 2  and illustrate that more rapid cooling was achieved with intermittent cooling. 
         [0047]    We then conducted further trials, varying the number of spins per cooling cycle. The results are shown in  FIG. 3 . It can be seen that rotation at higher speeds and with a higher number of pauses in rotation produces a steeper cooling gradient. 
         [0048]    Based on the above results, further trials were conducted at 360 rpm with rotation for 10 seconds followed by a 20 second pause to show the effect over time on can temperature. The results are shown in Table 2. 
         [0000]    
       
         
               
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
             
           
               
                 TABLE 2 
               
               
                   
               
               
                   
                   
                 Tank 
                 Tank 
                 Temp 
                 Temp 
                   
                   
               
               
                 Cooling 
                 Number 
                 start 
                 end 
                 Can 
                 Can 
                 Temp 
                 Average 
               
               
                 time 
                 of spin 
                 temp 
                 temp 
                 base 
                 middle 
                 Can top 
                 Temp 
               
               
                 (sec) 
                 cycles 
                 (° C.) 
                 (° C.) 
                 (° C.) 
                 (° C.) 
                 (° C.) 
                 (° C.) 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 0 
                 — 
                 — 
                 — 
                 24 
                 24 
                 24 
                 24 
               
               
                 30 
                 1 
                 −16 
                 −15 
                 13 
                 14 
                 14 
                 13.6 
               
               
                 60 
                 2 
                 −14 
                 −12 
                 8 
                 9 
                 9 
                 8.6 
               
               
                 90 
                 3 
                 −15 
                 −14 
                 7 
                 6 
                 6 
                 6.3 
               
               
                 90 
                 3 
                 −14 
                 −12 
                 7 
                 6 
                 6 
                 6.3 
               
               
                 120 
                 4 
                 −14 
                 −13 
                 1 
                 1 
                 1 
                 1 
               
               
                   
               
             
          
         
       
     
         [0049]    These results show that optimum cooling, in terms of achieving a beverage cooled uniformly to the desired temperature in the range of 6° C., is achievable with three cycles, over 90 seconds. It was noted that the cooling liquid (4 litres) rose in temperature by 1.5° C. for each trial.  FIG. 4  shows the averaged results of a large series of these trials with cans at initial temperatures of 24° C. 
         [0050]    We have calculated that the total energy required to cool a can from an ambient temperature of about 24° C. to about 6° C. is around 6 joules; according to the following calculations: 
         [0000]      Mass of drinks can=355 g water+39 g (typical) sugar 
         [0000]      Thermal Energy,  Q =Mass×Specific Heat Capacity×Change in temperature
 
         [0051]    Theoretical Drink Calculation 
         [0000]    
       
      
       Q 
       drink 
       =M×C×ΔT  
      
     
         [0000]        Q   drink =0.394×0.58×−18
 
         [0000]        Q   drink =4.11 joules 
         [0052]    Theoretical Can Calculation 
         [0000]    
       
      
       Q 
       can 
       M×C×ΔT  
      
     
         [0000]        Q   can =(surface area×thickness×mass of aluminium)×237×48
 
         [0000]        Q   can =(0.032012×0.00025×56.5)×237×−18
 
         [0000]        Q   can =1.93 joules 
         [0053]    Total energy required to cool a single can+beverage=Q can +Q drink =6.04 joules 
         [0054]    The following set out the principle advantages of the apparatus of the present invention over the state of the art cooling methodologies:
       1. Rotating the can at an optimal speed to improve forced convection;   2. Generating a free (decaying) vortex within the can to promote natural cooling convection; and   3. Combining a series of forced and free (decaying) vortexes to cool a beverage rapidly, with an evenly distributed temperature.       
 
         [0058]    In preferred embodiments, the apparatus further comprises a sleeve into which the container to be cooled is filled, such as a rubber membrane, preferably a membrane including metallic particles to improve thermal conductivity. The inclusion of a closely-fitting membrane acts to reduce or prevent damage to labelling on the container, especially if paper labels are used. 
         [0059]    The full results data from Tests 1 to 7 are given in Table 3. 
         [0060]    For commercial uses, it is advantageous for the apparatus to include a plurality of cavities of the type described above for simultaneous chilling of several containers. 
         [0061]    In typical embodiments, the apparatus is incorporated in a vending apparatus and further comprises insertion and removal means for inserting the product to be cooled into the cavity and removing the cooled product therefrom. 
         [0062]    Preferably, the vending apparatus further comprises storage means for storing a product or range of products and selection means for selecting a product from the storage means for insertion into the cavity. 
         [0063]    The vending apparatus will typically also include payment collection apparatus such as a coin-operated mechanism or a card-reading apparatus for deducting a charge from a card. 
         [0000]    
       
         
               
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
             
           
               
                 TABLE 3 
               
               
                   
               
               
                   
                   
                   
                   
                   
                 Test Set 5 
                 Test Set 6 
                 Test Set 7 
               
               
                   
                 Test Set 1 
                 Test Set 2 
                 Test Set 3 
                 Test Set 4 
                 180 rpm 
                 360 rpm 
                 360 rpm 
               
               
                   
                 90 rpm 
                 180 rpm 
                 360 rpm 
                 360 rpm 
                 (3 Hz) 
                 (6 Hz) 
                 (6 Hz) 
               
               
                   
                 continuous 
                 continuous 
                 continuous 
                 intermittent 
                 intermittent 
                 intermittent 
                 intermittent 
               
               
                 Cooling 
                 (1.5 Hz) 
                 (3 Hz) 
                 (6 Hz) 
                 (6 Hz) 
                 (3 spins) 
                 (2 spins) 
                 (3 spins) 
               
               
                 time/ 
                 Can 
                 Can 
                 Can 
                 Can 
                 Can 
                 Can 
                 Can 
               
               
                 sec 
                 Temperature 
                 Temperature 
                 Temperature  
                 Temperature 
                 Temperature  
                 Temperature  
                 Temperature 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 0 
                 22.021 
                 22.021 
                 20.023 
                 22.522 
                 17.51 
                 16.002 
                 16.002 
               
               
                 2 
                 21.52 
                 21.52 
                 19.52 
                 22.021 
                 17.008 
                 15.5 
                 15.5 
               
               
                 4 
                 21.52 
                 20.518 
                 19.52 
                 21.52 
                 17.008 
                 15.5 
                 15.5 
               
               
                 6 
                 21.52 
                 20.017 
                 19.52 
                 21.019 
                 17.008 
                 15.5 
                 14.997 
               
               
                 8 
                 21.019 
                 19.015 
                 19.018 
                 20.017 
                 16.505 
                 14.997 
                 14.997 
               
               
                 10 
                 20.518 
                 18.514 
                 19.018 
                 19.516 
                 16.505 
                 14.494 
                 15.5 
               
               
                 12 
                 20.017 
                 18.012 
                 18.515 
                 18.514 
                 16.002 
                 14.494 
                 15.5 
               
               
                 14 
                 20.017 
                 17.511 
                 18.515 
                 18.012 
                 16.002 
                 13.991 
                 15.5 
               
               
                 16 
                 19.516 
                 17.01 
                 18.013 
                 17.01 
                 15.5 
                 13.488 
                 14.997 
               
               
                 18 
                 19.015 
                 16.008 
                 18.013 
                 16.509 
                 14.997 
                 13.488 
                 14.997 
               
               
                 20 
                 18.514 
                 15.507 
                 17.51 
                 16.008 
                 14.494 
                 12.986 
                 14.997 
               
               
                 22 
                 18.012 
                 15.507 
                 17.51 
                 15.507 
                 14.494 
                 12.483 
                 14.494 
               
               
                 24 
                 17.511 
                 15.507 
                 17.008 
                 14.505 
                 13.991 
                 12.483 
                 14.494 
               
               
                 26 
                 17.511 
                 15.507 
                 17.008 
                 14.004 
                 13.991 
                 11.98 
                 13.991 
               
               
                 28 
                 17.01 
                 15.507 
                 16.505 
                 13.502 
                 13.488 
                 11.98 
                 13.488 
               
               
                 30 
                 16.509 
                 15.507 
                 16.002 
                 13.001 
                 13.488 
                 11.477 
                 12.986 
               
               
                 32 
                 16.509 
                 15.507 
                 16.002 
                 11.999 
                 13.488 
                 11.477 
                 12.483 
               
               
                 34 
                 16.509 
                 15.006 
                 15.5 
                 11.498 
                 13.488 
                 10.974 
                 11.477 
               
               
                 36 
                 16.008 
                 15.006 
                 14.997 
                 10.495 
                 13.488 
                 10.974 
                 11.477 
               
               
                 38 
                 16.008 
                 14.505 
                 14.494 
                 9.994 
                 13.488 
                 10.974 
                 10.974 
               
               
                 40 
                 16.008 
                 13.502 
                 13.991 
                 9.492 
                 13.488 
                 10.471 
                 10.471 
               
               
                 42 
                 15.507 
                 13.001 
                 13.991 
                 8.991 
                 13.488 
                 10.471 
                 10.471 
               
               
                 44 
                 15.507 
                 11.999 
                 13.488 
                 8.49 
                 13.488 
                 9.968 
                 9.968 
               
               
                 46 
                 15.507 
                 11.498 
                 12.986 
                 7.487 
                 12.986 
                 9.968 
                 9.968 
               
               
                 48 
                 15.507 
                 10.996 
                 12.483 
                 6.986 
                 12.986 
                 9.464 
                 9.464 
               
               
                 50 
                 15.507 
                 9.994 
                 11.98 
                 6.986 
                 12.483 
                 9.464 
                 9.464 
               
               
                 52 
                 15.507 
                 9.492 
                 11.477 
                 6.484 
                 12.483 
                 8.961 
                 8.961 
               
               
                 54 
                 15.507 
                 8.49 
                 10.974 
                 6.484 
                 11.98 
                 8.961 
                 8.961 
               
               
                 56 
                 15.507 
                 7.989 
                 10.974 
                 6.484 
                 11.98 
                 8.961 
                 8.961 
               
               
                 58 
                 15.507 
                 7.487 
                 10.471 
                 6.484 
                 11.477 
                 8.458 
                 8.961 
               
               
                 60 
                 15.006 
                 6.484 
                 10.471 
                 6.484 
                 11.477 
                 8.458 
                 8.458 
               
               
                 62 
                 14.505 
                 5.983 
                 10.471 
                 6.986 
                 10.974 
                 7.955 
                 8.458 
               
               
                 64 
                 14.004 
                 5.482 
                 9.968 
                 7.989 
                 10.974 
                 7.955 
                 8.458 
               
               
                 66 
                 14.004 
                 4.98 
                 9.968 
                 8.49 
                 10.471 
                 7.452 
                 8.458 
               
               
                 68 
                 13.502 
                 4.479 
                 9.968 
                 8.991 
                 10.471 
                 7.452 
                 7.955 
               
               
                 70 
                 13.502 
                 3.977 
                 9.464 
                 9.492 
                 9.968 
                 7.452 
                 7.955 
               
               
                 72 
                 13.001 
                 3.476 
                 9.464 
                 9.994 
                 9.968 
                 7.452 
                 7.452 
               
               
                 74 
                 13.001 
                 2.975 
                 8.961 
                 10.495 
                 9.968 
                 6.948 
                 7.452 
               
               
                 76 
                 13.001 
                 2.473 
                 8.961 
                 10.495 
                 9.968 
                 6.948 
                 6.948 
               
               
                 78 
                 13.001 
                 1.972 
                 8.458 
                 10.495 
                 9.464 
                 6.948 
                 6.948 
               
               
                 80 
                 13.502 
                 1.972 
                 8.458 
                 10.495 
                 9.464 
                 6.445 
                 6.948 
               
               
                 82 
                 13.502 
                 1.47 
                 7.955 
                 10.495 
                 9.464 
                 6.445 
                 6.445 
               
               
                 84 
                 13.502 
                 0.969 
                 7.955 
                 10.495 
                 8.961 
                 5.942 
                 6.445 
               
               
                 86 
                 13.502 
                 0.467 
                 7.452 
                 10.495 
                 8.961 
                 5.942 
                 5.942 
               
               
                 88 
                 13.502 
                 0.467 
                 7.452 
                 10.495 
                 8.458 
                 5.439 
                 5.942 
               
               
                 90 
                 13.502 
                 −0.035 
                 7.452 
                 10.495 
                 7.955 
                 5.439 
                 5.439 
               
               
                 92 
                 13.502 
                 −0.035 
                 6.948 
                 10.495 
                 7.955 
                 5.439 
                 5.439 
               
               
                 94 
                 13.502 
                 −0.035 
                 6.948 
                 10.495 
                 7.452 
                 4.935 
                 4.935 
               
               
                 96 
                 13.502 
                 −0.035 
                 6.445 
                 10.996 
                 7.452 
                 4.935 
                 4.935 
               
               
                 98 
                 13.502 
                 −0.035 
                 6.445 
                 10.996 
                 7.452 
                 4.935 
                 4.935 
               
               
                 100 
                 13.502 
                 −0.035 
                 5.942 
                 10.996 
                 6.948 
                 4.432 
                 4.432 
               
               
                 102 
                 13.502 
                 −0.035 
                 5.942 
                 10.996 
                 6.948 
                 4.432 
                 4.432 
               
               
                 104 
                 13.502 
                 −0.035 
                 5.942 
                 10.996 
                 6.445 
                 4.432 
                 3.928 
               
               
                 106 
                 13.502 
                 −0.536 
                 5.942 
                 10.996 
                 6.445 
                 4.432 
                 3.928 
               
               
                 108 
                 13.001 
                 −0.536 
                 5.942 
                 10.996 
                 5.942 
                 4.432 
                 3.425 
               
               
                 110 
                 13.001 
                 −0.536 
                 5.942 
                 10.996 
                 5.942 
                 3.928 
                 2.921 
               
               
                 112 
                 13.001 
                 −0.536 
                 5.942 
                 10.495 
                 5.942 
                 3.928 
                 2.921 
               
               
                 114 
                 13.001 
                 −0.536 
                 5.942 
                 10.495 
                 5.439 
                 3.928 
                 2.418 
               
               
                 116 
                 12.5 
                 −0.536 
                 5.942 
                 10.495 
                 5.439 
                 3.928 
                 2.418 
               
               
                 118 
                 12.5 
                 −0.536 
                 5.942 
                 9.994 
                 5.439 
                 3.425 
                 1.914 
               
               
                 120 
                 12.5 
                 −0.536 
                 5.942 
                 9.994 
                 5.439 
                 3.425 
                 1.914 
               
               
                 122 
                 12.5 
                 −1.038 
                 5.439 
                 9.492 
                 4.935 
                 3.425 
                 1.914 
               
               
                 124 
                 11.999 
                 −1.038 
                 5.439 
                 8.991 
                 4.935 
                 3.425 
                 1.41 
               
               
                 126 
                 11.999 
                 −1.038 
                 4.935 
                 8.991 
                 4.935 
                 3.425 
                 1.41 
               
               
                 128 
                 11.999 
                 −1.038 
                 4.935 
                 8.49 
                 4.432 
                 2.921 
                 1.41 
               
               
                 130 
                 11.498 
                 −1.038 
                 4.432 
                 8.49 
                 4.432 
                 2.921 
                 0.907 
               
               
                 132 
                 10.996 
                 −1.038 
                 4.432 
                 8.49 
                 3.928 
                 2.921 
                 0.907 
               
               
                 134 
                 10.495 
                 −1.038 
                 3.928 
                 7.989 
                 3.928 
                 2.921 
                 0.907 
               
               
                 136 
                 9.492 
                 −1.038 
                 3.425 
                 7.989 
                 3.425 
                 2.921 
                 0.907 
               
               
                 138 
                 8.991 
                 −1.038 
                 3.425 
                 7.989 
                 3.425 
                 2.418 
                 0.403 
               
               
                 140 
                 7.989 
                 −1.038 
                 2.921 
                 7.487 
                 3.425 
                 2.418 
                 0.403 
               
               
                 142 
                 7.487 
                 −1.038 
                 2.921 
                 7.487 
                 2.921 
                 2.418 
                 0.403 
               
               
                 144 
                 6.986 
                 −1.038 
                 2.418 
                 7.487 
                 2.921 
                 2.418 
                 0.403 
               
               
                 146 
                 6.484 
                 −1.038 
                 2.418 
                 7.487 
                 2.418 
                 2.418 
                 0.403 
               
               
                 148 
                 5.983 
                 −1.038 
                 2.418 
                 6.986 
                 2.418 
                 2.418 
                 −0.101 
               
               
                 150 
                 5.482 
                 −1.038 
                 2.418 
                 6.986 
                 1.914 
                 1.914 
                 −0.101 
               
               
                 152 
                 4.98 
                 −1.038 
                 2.418 
                 6.986 
                 1.914 
                 1.914 
                 −0.101 
               
               
                 154 
                 4.479 
                 −1.038 
                 2.418 
                 6.484 
                 1.914 
                 1.914 
                 −0.101 
               
               
                 156 
                 4.479 
                 −1.038 
                 2.418 
                 6.484 
                 1.914 
                 1.914 
                 −0.101 
               
               
                 158 
                 3.977 
                 −1.038 
                 1.914 
                 6.484 
                 1.41 
                 1.914 
                 −0.101 
               
               
                 160 
                 3.476 
                 −1.038 
                 1.914 
                 5.983 
                 1.41 
                 1.914 
                 −0.101 
               
               
                 162 
                 3.476 
                 −1.038 
                 2.418 
                 5.983 
                 1.41 
                 1.914 
                 −0.101 
               
               
                 164 
                 2.975 
                 −1.038 
                 2.921 
                 5.983 
                 1.41 
                 1.914 
                 −0.101 
               
               
                 166 
                 2.975 
                 −1.038 
                 2.921 
                 5.482 
                 0.907 
                 1.41 
                 −0.101 
               
               
                 168 
                 2.473 
                 −1.038 
                 3.425 
                 5.482 
                 0.907 
                 1.41 
                 −0.604 
               
               
                 170 
                 2.473 
                 −1.038 
                 3.928 
                 5.482 
                 0.907 
                 1.41 
                 −0.604 
               
               
                 172 
                 1.972 
                 −1.038 
                 3.928 
                 5.482 
                 0.907 
                 1.41 
                 −0.604 
               
               
                 174 
                 1.972 
                 −1.038 
                 4.432 
                 4.98 
                 0.907 
                 1.41 
                 −0.604 
               
               
                 176 
                 1.972 
                 −0.536 
                 4.432 
                 4.98 
                 0.403 
                 1.41 
                 −0.604 
               
               
                 178 
                 1.47 
                 −0.536 
                 4.935 
                 4.98 
                 0.403 
                 1.41 
                 −0.604 
               
               
                 180 
                 1.47 
                 −0.536 
                 4.935 
                 4.479 
                 0.403 
                 1.41 
                 −0.604 
               
               
                 182 
                 1.972 
                 −0.536 
                 4.935 
                 4.479 
                 0.403 
                 1.41 
                 −0.604 
               
               
                 184 
                 1.972 
                 −0.536 
                 4.935 
                 4.479 
                 0.403 
                 1.41 
                 −0.604 
               
               
                 186 
                 1.972 
                 −0.536 
                 5.439 
                 3.977 
                 0.403 
                 1.41 
                 −0.604 
               
               
                 188 
                 2.473 
                 −0.035 
                 5.439 
                 3.977 
                 0.403 
                 1.41 
                 −0.604 
               
               
                 190 
                 2.473 
                 −0.035 
                 5.439 
                 3.977 
                 −0.101 
                 1.41 
                 −0.604 
               
               
                 192 
                 2.975 
                 0.467 
                 5.439 
                 3.476 
                 −0.101 
                 1.41 
                 −0.604 
               
               
                 194 
                 2.975 
                 0.969 
                 5.439 
                 3.476 
                 −0.101 
                 0.907 
                 −0.604 
               
               
                 196 
                 2.975 
                 1.47 
                 5.439 
                 3.476 
                 −0.101 
                 0.907 
                 −0.604 
               
               
                 198 
                 3.476 
                 1.972 
                 5.439 
                 2.975 
                 −0.101 
                 0.907 
                 −0.604 
               
               
                 200 
                 3.476 
                 2.473 
                 5.439 
                 2.975 
                 −0.101 
                 0.907 
                 −0.604 
               
               
                 202 
                 3.476 
                 2.975 
                 5.439 
                 2.975 
                 −0.101 
                 0.907 
                 −0.604 
               
               
                 204 
                 3.977  
                 2.975 
                 5.439 
                 2.473 
                 −0.101 
                 0.907 
                 −0.604 
               
               
                 206 
                 3.977 
                 3.476 
                 5.439 
                 2.473 
                 −0.101 
                 0.907 
                 −0.604 
               
               
                 208 
                 3.977 
                 3.476 
                 5.439 
                 2.473 
                 −0.101 
                 0.907 
                 −0.604 
               
               
                 210 
                 3.977 
                 3.977 
                 5.439 
                 2.473 
                 −0.101 
                 0.907 
                 −0.604 
               
               
                 212 
                 3.977 
                 3.977 
                 4.935 
                 1.972 
                 −0.101 
                 0.907 
                 −0.604 
               
               
                 214 
                 3.977 
                 3.977 
                 4.935 
                 1.972 
                 −0.604 
                 0.907 
                 −0.604 
               
               
                 216 
                 4.479 
                 4.479 
                 4.935 
                 1.972 
                 −0.604 
                 0.907 
                 −0.604 
               
               
                 218 
                 4.479 
                 4.479 
                 4.935 
                 1.972 
                 −0.604 
                 0.907 
                 −1.108 
               
               
                 220 
                 4.479 
                 4.479 
                 4.935 
                 1.972 
                 −0.604 
                 0.907 
                 −0.604 
               
               
                 222 
                 4.479 
                 4.479 
                 4.935 
                 1.47 
                 −0.604 
                 0.907 
                 −1.108 
               
               
                 224 
                 4.479 
                 4.479 
                 4.935 
                 1.47 
                 −0.604 
                 0.907 
                 −0.604 
               
               
                 226 
                 4.479 
                 4.479 
                 4.432 
                 1.47 
                 −0.604 
                 0.907 
                 −1.108 
               
               
                 228 
                 4.479 
                 4.479 
                 4.432 
                 1.47 
                 −0.604 
                 0.907 
                 −1.108 
               
               
                 230 
                 4.479 
                 4.479 
                 4.432 
                 1.47 
                 −0.604 
                 0.907 
                 −1.108 
               
               
                 232 
                 4.479 
                 4.479 
                 4.432 
                 1.47 
                 −0.604 
                 0.907 
                 −1.108 
               
               
                 234 
                 4.479 
                 4.479 
                 4.432 
                 0.969 
                 −0.604 
                 0.907 
                 −0.604 
               
               
                 236 
                 3.977 
                 4.479 
                 4.432 
                 0.969 
                 −0.604 
                 0.907 
                 −1.108 
               
               
                 238 
                 3.977 
                 4.479 
                 4.432 
                 0.969 
                 −0.604 
                 0.907 
                 −1.108 
               
               
                 240 
                 3.977 
                 4.479 
                 3.928 
                 0.969 
                 −0.604 
                 0.907 
                 −1.108 
               
               
                 242 
                 3.977 
                 4.479 
                 3.928 
                 0.969 
                 −0.604 
                 0.907 
                 −1.108 
               
               
                 244 
                 3.977 
                 4.479 
                 3.928 
                 0.969 
                 −0.604 
                 0.907 
                 −1.108 
               
               
                 246 
                 3.977 
                 4.479 
                 3.928 
                 0.969 
                 −0.604 
                 0.907 
                 −1.108 
               
               
                 248 
                 3.977 
                 4.479 
                 3.928 
                 0.969 
                 −0.604 
                 0.907 
                 −1.108 
               
               
                 250 
                 3.977 
                 4.479 
                 3.928 
                 0.969 
                 −0.604 
                 0.907 
                 −0.604 
               
               
                 252 
                 3.977 
                 4.479 
                 3.928 
                 0.969 
                 −0.604 
                 0.907 
                 −0.604 
               
               
                 254 
                 3.977 
                 4.479 
                 3.928 
                 0.969 
                 −0.604 
                 0.907 
                 −0.604 
               
               
                 256 
                 3.977 
                 4.479 
                 3.928 
                 0.969 
                 −0.604 
                 0.907 
                 −0.604 
               
               
                 258 
                 3.977 
                 4.479 
                 3.928 
                 0.969 
                 −0.604 
                 0.907 
                 −0.604 
               
               
                 260 
                 3.977 
                 4.479 
                 3.928 
                 0.467 
                 −0.604 
                 0.907 
                 −0.604 
               
               
                 262 
                 3.977 
                 4.479 
                 3.928 
                 0.467 
                 −0.604 
                 0.907 
                 −0.604 
               
               
                 264 
                 3.977 
                 4.479 
                 3.928 
                 0.467 
                 −0.604 
                 0.907 
                 −0.604 
               
               
                 266 
                 3.977 
                 4.479 
                 3.425 
                 0.467 
                 −0.604 
                 0.907 
                 −0.604 
               
               
                 268 
                 3.977 
                 4.479 
                 3.425 
                 0.467 
                 −0.604 
                 0.907 
                 −0.604 
               
               
                 270 
                 3.977 
                 4.479 
                 3.425 
                 0.467 
                 −0.604 
                 0.403 
                 −0.604 
               
               
                 272 
                 3.977 
                 4.479 
                 3.425 
                 0.467 
                 −0.604 
                 0.403 
                 −0.604 
               
               
                 274 
                 3.977 
                 4.479 
                 3.425 
                 0.467 
                 −0.604 
                 0.403 
                 −0.604 
               
               
                 276 
                 3.977 
                 4.479 
                 3.425 
                 0.467 
                 −0.604 
                 0.403 
                 −0.604 
               
               
                 278 
                 3.977 
                 4.479 
                 3.425 
                 0.467 
                 −0.604 
                 0.403 
                 −0.604 
               
               
                 280 
                 3.977 
                 4.479 
                 3.425 
                 0.467 
                 −0.604 
                 0.403 
                 −0.604 
               
               
                 282 
                 3.977 
                 4.479 
                 3.425 
                 0.467 
                 −0.604 
                 0.403 
                 −0.604 
               
               
                 284 
                 3.977 
                 4.479 
                 3.425 
                 0.467 
                 −0.604 
                 0.403 
                 −0.604 
               
               
                 286 
                 3.977 
                 4.479 
                 3.425 
                 0.467 
                 −0.604 
                 0.403 
                 −0.604 
               
               
                 288 
                 3.977 
                 4.479 
                 3.425 
                 0.467 
                 −0.604 
                 0.403 
                 −0.604 
               
               
                 290 
                 3.977 
                 4.479 
                 3.425 
                 0.467 
                 −0.604 
                 0.403 
                 −0.604 
               
               
                 292 
                 3.977 
                 4.479 
                 3.425 
                 0.467 
                 −0.604 
                 0.403 
                 −0.604 
               
               
                 294 
                 3.977 
                 4.479 
                 3.425 
                 0.467 
                 −0.604 
                 0.403 
                 −0.604 
               
               
                 296 
                 3.977 
                 4.479 
                 3.425 
                 0.467 
                 −0.604 
                 0.907 
                 −0.604 
               
               
                 298 
                 3.977 
                 4.479 
                 3.425 
                 0.467 
                 −0.604 
                 1.41 
                 −0.604 
               
               
                 300 
                 3.977 
                 4.479 
                 3.425 
                 0.467 
                 −0.604 
                 2.418 
                 −0.604 
               
               
                 302 
                   
                   
                   
                   
                 −0.604 
                 2.921 
                 −0.604 
               
               
                 304 
                   
                   
                   
                   
                 −0.604 
                 3.928 
                 −0.604 
               
               
                 306 
                   
                   
                   
                   
                 −0.604 
                 4.432 
                 −0.604 
               
               
                 308 
                   
                   
                   
                   
                 −0.604 
                 5.439 
                 −0.604 
               
               
                 310 
                   
                   
                   
                   
                 −0.604 
                 5.942 
                 −0.604 
               
               
                 312 
                   
                   
                   
                   
                 −0.604 
                 6.445 
                 −0.604 
               
               
                 314 
                   
                   
                   
                   
                 −0.604 
                 7.452 
                 −0.604 
               
               
                 316 
                   
                   
                   
                   
                 −0.604 
                 7.955 
                 −0.604 
               
               
                 318 
                   
                   
                   
                   
                 −0.604 
                 8.458 
                 −0.604 
               
               
                 320 
                   
                   
                   
                   
                 −0.604 
                 8.961 
                 −0.604 
               
               
                 322 
                   
                   
                   
                   
                 −0.604 
                 9.968 
                 −0.604 
               
               
                 324 
                   
                   
                   
                   
                 −0.604 
                 10.471 
                 −0.604 
               
               
                 326 
                   
                   
                   
                   
                 −0.604 
                 10.974 
                 −0.604 
               
               
                 328 
                   
                   
                   
                   
                 −0.604 
                 11.477 
                 −0.604 
               
               
                 330 
                   
                   
                   
                   
                 −0.604 
                 11.98 
                 −0.604 
               
               
                 332 
                   
                   
                   
                   
                 −0.604 
                 12.483 
                 −0.604 
               
               
                 334 
                   
                   
                   
                   
                 −0.604 
                 12.986 
                 −0.604 
               
               
                 336 
                   
                   
                   
                   
                 −0.604 
                 13.488 
                 −0.604 
               
               
                 338 
                   
                   
                   
                   
                 −0.604 
                 13.991 
                 −0.604 
               
               
                 340 
                   
                   
                   
                   
                 −0.604 
                 14.494 
                 −0.604 
               
               
                 342 
                   
                   
                   
                   
                 −0.604 
                 14.997 
                 −0.604 
               
               
                 344 
                   
                   
                   
                   
                 −0.604 
                 15.5 
                 −0.604 
               
               
                 346 
                   
                   
                   
                   
                 −0.604 
                 16.002 
                 −0.604 
               
               
                 348 
                   
                   
                   
                   
                 −0.604 
                 16.505 
                 −0.604 
               
               
                 350 
                   
                   
                   
                   
                 −0.604 
                 17.008 
                 −0.604 
               
               
                 352 
                   
                   
                   
                   
                 −0.604 
                 17.008 
                 −0.604 
               
               
                 354 
                   
                   
                   
                   
                 −0.604 
                 17.51 
                 −0.604 
               
               
                 356 
                   
                   
                   
                   
                 −0.101 
                 18.013 
                 −0.604 
               
               
                 358 
                   
                   
                   
                   
                 0.907 
                 18.013 
                 −0.604 
               
               
                 360 
                   
                   
                   
                   
                 1.41 
                 18.515 
                 −0.604 
               
               
                 362 
                   
                   
                   
                   
                 1.914 
                 19.018 
                 −0.604 
               
               
                 364 
                   
                   
                   
                   
                 2.921 
                 19.52 
                 −0.604 
               
               
                 366 
                   
                   
                   
                   
                 3.928 
                 19.52 
                 −0.604 
               
               
                 368 
                   
                   
                   
                   
                 4.432 
                 20.023 
                 −0.604 
               
               
                 370 
                   
                   
                   
                   
                 4.935 
                 20.525 
                 −0.604 
               
               
                 372 
                   
                   
                   
                   
                 5.439 
                 20.525 
                 −0.604 
               
               
                 374 
                   
                   
                   
                   
                 6.445 
                 21.028 
                 −0.604 
               
               
                 376 
                   
                   
                   
                   
                 6.948 
                 21.028 
                 −0.604 
               
               
                 378 
                   
                   
                   
                   
                 7.452 
                 21.53 
                 −0.604 
               
               
                 380 
                   
                   
                   
                   
                 7.955 
                 21.53 
                 −0.604 
               
               
                 382 
                   
                   
                   
                   
                 8.458 
                   
                 −0.604 
               
               
                 384 
                   
                   
                   
                   
                 8.961 
                   
                 −0.604 
               
               
                 386 
                   
                   
                   
                   
                 8.961 
                   
                 −0.604 
               
               
                 388 
                   
                   
                   
                   
                 9.464 
                   
                 −0.604 
               
               
                 390 
                   
                   
                   
                   
                 9.968 
                   
                 −0.604 
               
               
                 392 
                   
                   
                   
                   
                 9.968 
                   
                 −0.604 
               
               
                 394 
                   
                   
                   
                   
                 10.471 
                   
                 −0.604 
               
               
                 396 
                   
                   
                   
                   
                 10.974 
                   
                 −0.604 
               
               
                 398 
                   
                   
                   
                   
                 11.477 
                   
                 −0.604 
               
               
                 400 
                   
                   
                   
                   
                 11.98 
                   
                 −0.604 
               
               
                   
               
             
          
         
       
     
         [0064]    Convective heat transfer is largely governed by the fluid flow regime within the boundary layer. Increasing the velocity gradient within the boundary layer will increase convective heat transfer. Whilst the Reynolds number is a key parameter governing whether the boundary layer is laminar or turbulent, it may transition due to surface texture or roughness and the local pressure gradient. The more complex motion of the container and coolant provided by this arrangement gives more degrees of freedom to control the thickness and velocity gradient within the boundary layer. This enables the apparatus to maximise convective heat transfer whilst eliminating slushing or ice formation that has hampered past attempts to achieve rapid cooling. 
         [0065]    The present invention also seeks to provide a vending machine incorporating the apparatus described above. In a conventional vending machine, the entire storage cavity must be insulated, but insulation for a cavity storing perhaps 400 cans can typically only be achieved using insulating foam or mats or other materials which trap air in order to prevent heat transmission. These materials are relatively inefficient thermal insulators. 
         [0066]    In addition to providing a vending machine which chills beverages exclusively on demand, the present invention provides a vending machine in which most cans or other beverage containers are storable at ambient temperature and only a small number, perhaps 16 or so, are storable at a reduced or drinking temperature. 
         [0067]    As a result, the cavity in which the reduced temperature containers are stored can be insulated by more effective means, such as vacuum insulation panels. The cooling apparatus is provided between the ambient storage cavity and the chilled storage cavity. 
         [0068]    The use of two storage zones significantly reduces the overall energy consumption and will also reduce the power rating required for the rapid cooling apparatus. 
         [0069]    Additional low level chilling to the chilled storage cavity can be provided to maintain the correct temperature, but the energy consumption to maintain the temperature in a small vacuum-insulated capacity cavity is substantially lower than in conventional machines. Table 4 compares the energy consumption of such a vending machine compared with a conventional machine in which all the cans are maintained at a chilled temperature. 
         [0000]    
       
         
               
               
               
             
               
               
               
             
           
               
                   
                 TABLE 4 
               
               
                   
                   
               
               
                   
                 Conventional 
                 Inventive 
               
               
                   
                 vending machine 
                 vending machine 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                 Power rating 
                 0.4 kW 
                 0.4 kW 
               
               
                 Storage Capacity 
                 400 cans 
                 400 cans 
               
               
                 Insulation 
                 PU foam 
                 Vacuum insulation 
               
               
                   
                   
                 panel* 
               
               
                   
                   
                 (for 16 - can chilled 
               
               
                   
                   
                 storage) 
               
               
                 Cooling rate 
                 NA 
                 60 seconds 
               
               
                 Energy consumption per can 
                 1080 kJ 
                 25-50 kJ 
               
               
                 Energy consumption per day for 
                 4.8-5.5 kWh 
                 1 kWh 
               
               
                 cooling (assuming 16 cans sold) 
               
               
                 Operating costs per annum 
                             340 
                             62 
               
               
                   
               
             
          
         
       
     
         [0070]    As can be seen the machine of the present invention will require 50 kJ to cool a can from ambient to drinking temperature (4-6° C.). In a typical scenario approximately 30 cans are sold each day. Assuming that these are dispensed randomly over 24 hours additional cooling to compensate for thermal losses in the chilled storage cavity is estimated to be a maximum of 0.5 kWh per day. Hence, the total energy consumption (in this scenario is will be 1 kWh for cooling 30 cans which remains an 80% saving compared with conventional machines.