GB2450925A

GB2450925A - An Ice Bank Cooler with a Coolant Freezing Below the Freezing Point of Water

Info

Publication number: GB2450925A
Application number: GB0713605A
Authority: GB
Inventors: Patrick William Johnson
Original assignee: INNSERVE Ltd
Current assignee: INNSERVE Ltd
Priority date: 2007-07-12
Filing date: 2007-07-12
Publication date: 2009-01-14
Anticipated expiration: 2027-07-12
Also published as: GB0713605D0; GB2450925B

Abstract

An ice bank cooler 50 which is used for cooling dispensed beverages, has a coolant reservoir 52 and an associated refrigeration unit. The refrigeration unit has a refrigerant pipe 62 for the circulating refrigerant, and a portion of the pipe is located in the coolant in order to form an ice bank. The freezing point of the coolant in the reservoir is below the freezing point of water, but above the operating temperature of the refrigerant. One or more products pipes (12 fig 1) are provided for carrying a product to be cooled, and a portion 66 of the product pipes is located in the coolant. The cooler may include a thermostat which switches the refrigeration unit on or off so as to maintain the coolant temperature within defined limits. The refrigeration pipe and the product pipes may be coiled, and the cooler may include a pump 70 for circulating coolant around a python (16 fig 1). The freezing point of the coolant may be higher than -5{C, and may include water and a freeze suppressant such as propylene glycol. The refrigeration unit may include a pump located in a refrigeration deck 64.

Description

Cooler This invention relates to cooling systems and in particular to

ice bank coolers.

Background

The most common cooling system employed in the mainstream UK draught beer industry for the last 30 years has been the remote ice bank cooler attached to a python loom. This effectively replaced the previous system using flash coolers placed under the dispense points below the bar counter which became common in the late 1960s with

the introduction of keg beer and cider products.

Remote ice bank cooler (with python) systems are designed to work with Cellar Temperature Control systems (CTC) which pre-cool the draught drinks down to typically 12 C. The product then is cooled by the remote ice bank cooler to about 6 C before being fed up a python (a bundle of insulated product lines) to a bar area. Remote ice bank cooler with python systems are typically used to provide dispense temperatures at the bar area of between 6 C and 8 C.

The remote ice bank cooler contains a reservoir of water and a refrigeration unit which forms an ice bank from the water. In the water, an inhibitor may be present to prevent corrosion. A plurality of product coils (carrying product such as beer) are cooled by the water so that the product is cooled from about 12 C to about 6 C. The ice bank effectively acts as a heat sink, which keeps the water at around 0 C.

Since the late 1990s there has been an increasing trend in the reduction of dispense temperatures of draught drinks. The required dispense temperatures of some drinks have fallen from the 6 C dispensed by the existing ice bank cooler technology to temperatures of 0 C to 3 C. These so-called "extra cold" lagers, stouts, ciders and ales are becoming common-place in retail bars.

The delivery of the "extra cold" temperatures has been achieved by a variety of technological solutions.

For example, it is known to use a supplementary cooling devices such as (but limited to) shelf coolers and pods at the point of dispense (i.e. in the bar area) to reduce the temperature from remote cooler outlet from about 6 C to about 3 C.

It is also known to approach extra cold temperatures with the existing remote ice bank coolers by using extra long product coils.

For very cold temperatures, "glycol coolers" have been developed. These coolers contain a reservoir of propylene glycol solution which is used to cool product coils. The solution contains about 25% propylene glycol by volume. The solution has a freezing point of about -10 C so can be cooled well below 0 C without freezing.

The propylene glycol solution is cooled to about -2 C (by circulating refrigerant at about -5 C) in order to produce a dispense temperature of about 0 C to 3 C.

Because the propylene glycol solution is only cooled to temperatures well above its freezing point, the propylene glycol solution does not freeze during operation of the "glycol cooler".

At its most general, the invention provides an ice bank cooler containing a coolant whose freezing point is below the freezing point of water and above the operating temperature of a refrigerant in a refrigeration pipe so that an ice bank is formed from the coolant when the cooler is in use.

According to a first aspect, there is provided an ice bank cooler as set out in claim 1.

In use, the ice bank cooler according to the first aspect is capable of forming an ice bank on the refrigeration pipes. The ice bank effectively provides a heat sink which maintains the liquid part of the coolant at a temperature which is approximately equal to the freezing point of the coolant. The liquid part of the coolant can then be used to cool a product, such as drink (e.g. beer).

Existing ice bank coolers have used water as a coolant (or a mixture of water and a corrosion inhibitor) . These previous coolers were not capable of maintaining the liquid part of the coolant (i.e. water) at a temperature below 0 C, as the water would have simply frozen. However, in the ice bank cooler according to the first aspect, the temperature of the liquid part of the coolant can be kept below 0 C without freezing.

Therefore, the ice bank cooler of the first aspect is able to cool a product more quickly and to lower temperatures than existing ice bank coolers.

The skilled person looking to make "extra cold" drinks would naturally look for a coolant that could be cooled to very low temperatures without freezing.

Accordingly, "glycol coolers" use propylene glycol solution at a concentration of about 25% as a liquid coolant. This solution has a freezing point of about -10 C. Therefore, "glycol coolers" are capable of producing liquid coolant which is much lower in temperature than existing ice bank coolers, without the liquid coolant becoming frozen.

The freezing point of the coolant in the cooler according to the first aspect is higher than in the above described "glycol coolers". Therefore, the liquid part of the coolant in the cooler according to the first aspect cannot be cooled to temperatures as low as the coolant in "glycol coolers". Nonetheless, it has been found that the cooler according to the first aspect is better at cooling large volumes of product than "glycol coolers". This is because, in use, the cooler according to the first aspect produces an ice bank from the reservoir of coolant. The ice bank effectively acts as a heat sink to maintain the temperature of the liquid part of the coolant at approximately the freezing point of the coolant as product is cooled by the ice bank cooler, even at high loads.

In contrast, the propylene glycol solution in "glycol coolers" warms up at high loads. To reduce this effect, "glycol coolers" are typically fitted with more powerful refrigeration units and/or a larger reservoir of coolant than equivalent ice bank coolers.

It had previously been thought that the fact that "glycol coolers" did not produce ice was advantageous over ice bank coolers, because heat exchange between the coolant and the refrigeration pipes was improved.

Therefore, the refrigeration units of "glycol coolers" were able to circulate refrigerant at relatively high temperatures (about -5 C) whilst still cooling drinks effectively.

The ice bank cooler according to the first aspect may be used as a remote unit, in other words, it can be located away from a bar area. Therefore, the ice bank cooler is advantageous over supplementary cooling devices used at the point of dispense, which take up bar space and cause excessive heating and/or condensation in bar areas.

The ice bank cooler may have a thermostat which includes a temperature sensor in the coolant for detecting the temperature of the coolant; and a controller for controlling the refrigeration unit according to the sensed temperature of the coolant, to regulate the temperature of the coolant and the size of the ice bank when the ice bank cooler is in use.

The thermostat may be adapted to switch on the refrigeration unit (i.e. begin refrigeration) when the detected temperature goes above a first threshold value and switch off the refrigeration unit (i.e. stop refrigeration) when the detected temperature goes below a second threshold value (which may be the same as the first threshold value) . The threshold value or values can therefore be set to determine the size of the ice bank, for a fixed sensor position. Suitable threshold values may be in the range -2 C to -6 C.

The size of the ice bank produced when the cooler is in use may be determined by adjusting the threshold values of the thermostat and/or by moving the location of the temperature sensor. A larger ice bank provides a cooler with more cooling capacity but less space for cooling product.

The portion of the refrigeration pipe in the coolant may be of copper or stainless steel. The portion of the refrigeration pipe in the coolant may be coiled. A coiled refrigeration pipe will help to improve the transfer of heat between the refrigeration pipe and the coolant. The portion of the refrigeration pipe in the coolant may be located at the periphery of the reservoir.

The ice bank cooler may include one or more product pipes for carrying a product to be cooled, a portion of each product pipe being in the coolant. The product pipes may be for carrying drink, e.g. beer, for cooling by the liquid part of the coolant. The portion of each product pipe in the coolant may be coiled, to improve the heat transfer between the liquid part of the coolant and the product. The product pipes may be of stainless steel.

The ice bank cooler may include a pump, for circulating some of the coolant around a python. This will enable product within the individual product lines in the python to be kept cool.

The pump may be adapted to agitate the reservoir of coolant. This will help maintain the liquid part of the coolant at a uniform temperature. Alternatively, there may be a separate agitation device for agitating the reservoir of coolant. The agitation device may be present in addition to any agitation function provided by the pump.

The "operating temperature" of the refrigerant refers to the temperature of the refrigerant when the refrigeration unit is operating (i.e. when it is refrigerating) . As noted above, the refrigeration unit may not always be operating, as it may be switched on and off by a thermostat. In other words, the "operating temperature" of the refrigerant is the temperature of the refrigerant when the cooler is in use. The operating temperature of the refrigerant may be in the range -5 C to -15 C. The operating temperature may be -10 C.

The temperature of the liquid part of the coolant when the ice bank cooler is in use is approximately equal to the freezing point of the coolant (for reasons explained in detail below) . Therefore, the freezing point of the coolant should be selected to be appropriate for cooling a product to the desired temperature.

In the case of "extra cold" drinks (which are preferably dispensed at a temperature in the range 0 C to 3 C), the freezing point of the coolant is preferably above -10 C, more preferably above -5 C, more preferably above -3 C, more preferably above -2.5 C. This may reduce the likelihood the product freezing. Preferably, the freezing point of the coolant is above the freezing point of the product so that the product won't be frozen by the liquid part of the coolant when the cooler is in use (e.g. beer freezes at around -3 C) The freezing point of the coolant is preferably below -0.5 C, more preferably below -1 C, more preferably below -1.5 C. This may enable the product to be sufficiently cooled by the liquid part of the coolant so as to achieve "extra cold" dispense temperatures when the cooler is in use. A preferred freezing point of the coolant is -2 C.

The coolant may be a solution which includes water and freeze suppressant. The freeze suppressant is preferably not toxic to humans.

The freeze suppressant may suitably be propylene glycol. Propylene glycol is relatively non corrosive (compared to brine for example), not toxic to humans, readily available and stable. Furthermore, propylene glycol can be diluted using potable water in situ, it is affordable and can have colourant added without deteriorating.

By controlling the proportion of propylene glycol (or any other freeze suppressant) in the solution, the freezing point of the coolant, and consequently the temperature of the liquid part of the coolant (when the cooler is in use) can be controlled. To achieve a coolant temperature suitable for cooling a product to a desired temperatures, a propylene glycol concentration of 0% to 10% by volume may be used. Preferably, the concentration of propylene glycol lies in the range 5% to 10% by volume, more preferably 6% to 8% by volume, more preferably 6.5% to 7.5% by volume. A particularly suitable concentration of propylene glycol is around 7% by volume. These concentrations have been found to achieve a solution with freezing points in the preferred ranges outlined above.

The coolant may include a corrosion inhibitor. This may be useful where the refrigeration pipe and/or the product pipes are corrodible (e.g. if they are of copper, for thermal reasons) According to a second aspect, the above described cooler may be part of a system for dispensing drinks. The system may include one or more dispensers for dispensing drinks which may be in fluid communication with one or more of the above described product pipes.

According to a third aspect, there may be provided a method of modifying an ice bank cooler. The method may include creating a reservoir of coolant in an ice bank cooler, by filling it with a coolant as set out above.

Therefore, according to this aspect, it is possible to create an ice bank cooler according to the first aspect by converting existing (water filled) ice bank coolers.

The method may include resetting, replacing or reconfiguring a thermostat in the cooler. This could lead to great cost savings for retail outlets wanting to serve "extra cold" drinks, without needing to incur the expense of new equipment. For example, "glycol coolers" can be expensive and they may require additional infrastructure in order to operate, such as a special electricity supply.

Embodiments of our proposals are discussed below, with reference to the accompanying drawings in which: Fig. 1 is a diagram showing a system for dispensing cooled drinks in a bar.

Fig. 2 is a perspective view of an ice bank cooler including enlarged views of the refrigeration pipe and product pipes of the ice bank cooler.

Fig. 3 is a cross sectional view of the ice bank cooler of Fig. 2 when it is in use.

Fig. 4 is a graph showing dispense temperature compared with the number of drinks dispensed over the period of an hour for three different coolants.

Fig. 5a is a photograph showing an ice bank cooler containing a reservoir of water.

Fig. 5b is a photograph showing an ice bank cooler containing a reservoir of solution containing water and 7% propylene glycol by volume.

Fig. 1 shows a system 1 for dispensing cooled drinks in a bar which uses conventional equipment. The system 1 includes a plurality of barrels 2 containing product (e.g. beer) . A gas supply 4 provides gas through gas pipes 6 to pumps 8 which pump product out from the barrels 2 through product lines 12.

The product lines 12 are fed into a python 16, which is an insulated pipe which contains a bundle of product lines 12. The insulation in the python 16 keeps the product cool. The product enters and exits an ice bank cooler 10 (which uses water as a coolant) by product lines 12 which also feed the product to a bar area 20.

The ice bank cooler 10 contains water which is cooled to about 0 C by an ice bank. The ice bank cooler cools the product from about 12 C to about 6 C. In addition, the ice bank cooler 10 also provides coolant pipes 18 in which cold water is circulated around the python 16 to keep the product within the python 16 chilled.

The bar area 20 includes a plurality of dispensers 22 for dispensing cooled product therefrom. The bar area also includes supplementary cooling units 24. The supplementary cooling units 24 provide additional cooling for the product in order to deliver "extra cold" drinks, at temperatures of about 0 C to 3 C at the bar area 20.

The supplementary cooling units 24 used with existing ice bank coolers take up space and create extra heat in the bar area 20.

Fig. 2 shows an ice bank cooler 50 for replacing the conventional ice bank cooler 10 shown in Fig. 1. The ice bank cooler 50 includes a reservoir of coolant 52.

The coolant 52 in the ice bank cooler is a solution including water and propylene glycol, with propylene glycol being included in a concentration of 7% by volume.

The coolant 52 has a freezing point of about -2 C.

The ice bank cooler 50 has a refrigeration unit 60 which includes a refrigeration pump (not shown) and a refrigeration pipe 62. The refrigeration pump is located in a refrigeration deck 64. When it is switched on, The refrigeration pump circulates a refrigerant around the refrigeration pipe 62 at a temperature of about -10 C. A portion of the refrigeration pipe 62 in the coolant 52 is coiled, to increase the speed of heat exchange between the refrigerant and the coolant 52.

A plurality of stainless steel product coils 66 for carrying product therethrough are in the coolant 52. In use, the product coils 66 are attached to the product lines 12 which, as explained previously, carry product from the barrels 2 to the bar area 20. Because the product coils 66 are coiled, the speed of heat exchange between the coolant 52 and the product in the product coils 66 is increased.

The ice bank cooler 50 includes a circulation pump 70. The circulation pump 70 is for pumping coolant 52 around coolant pipes 18 (shown in Fig. 1) to circulate coolant around the python 16 to keep the product within the python 16 chilled. The circulation pump 70 also provides agitation within the reservoir of coolant 52, to ensure an even distribution of temperature.

The ice bank cooler 50 includes an electric thermostat which includes a temperature sensor 80 (see Fig. 3) and a controller (not shown) . The temperature sensor 80 is located in the coolant 52 and detects the temperature of the coolant 52. The controller controls the refrigeration unit according to the temperature sensed by the temperature sensor 80.

Fig. 3 shows the ice bank cooler 50 of Fig. 2 in use. As the refrigerant in the refrigeration pipe 62 cools the coolant 52, an ice bank 54 (shown by the hatched area on Fig. 3) is formed from the coolant 52.

The ice bank 54 is formed around the refrigeration pipe 62, at the periphery of the reservoir. When the refrigeration unit is operating, the refrigerant in the refrigeration pipe 62 is at about -10 C. The ice bank 54 surrounds a remaining part of the coolant 52 which remains as a liquid 56. The liquid part of the coolant 56 surrounds the product coils 66.

There is a temperature gradient within the ice bank 54, which has its lowest temperature in the parts closest to the refrigeration pipe 62. The temperature of the ice bank 54 gradually increases towards a boundary 58 between the ice bank 54 and the liquid 56. At the boundary 58, the temperatures of the ice bank 54 and the liquid part of the coolant 56 are approximately equal and roughly correspond to the freezing point of the coolant 52 which, in this particular embodiment, is about -2 C.

The pump 70 agitates the liquid part of the coolant 56 to ensure an even temperature distribution within the liquid 56. The liquid part of the coolant 56 is maintained at a temperature of about the freezing point of the coolant 52, because it is in contact with the ice bank 54 at the boundary 58.

The product in the product coils 66 is cooled by heat exchange with the liquid 56. However, the heat taken from the product in this process does not cause the temperature of the liquid part of the coolant 56 to rise, because this heat is taken away by the ice bank 54 (which maintains the temperature of the liquid coolant at about the freezing point of the coolant as described above) . In other words, heat taken from the product in the product coils 66 is absorbed by the ice bank 54 to keep the temperature of the liquid part of the coolant 56 at about the freezing point of the coolant 52. The heat absorbed by the ice bank 54 is taken away by the refrigeration pipe 62.

During busy periods (i.e. when a lot of product is being cooled), the heat absorbed by the ice bank 54 exceeds the amount of heat taken away by the refrigeration pipe 62. In this scenario, a portion of the ice bank 54 will be melted by the excess heat in the system. However, the liquid part of the coolant 56 is maintained at about the freezing point of the coolant (-2 C) throughout by thermal contact with the non-melted part of the ice bank 54. In quieter periods, the ice bank 54 is able to grow back to its maximum size.

Therefore it can be seen that the ice bank 54 effectively acts as a heat sink, which is capable of maintaining the liquid part of the coolant 56 at temperatures close to its freezing point (-2 C), even at high loads.

Because the temperature of the liquid part of the coolant 56 corresponds approximately to the freezing point of the coolant 52, the desired temperature of the liquid part of the coolant 56 can be achieved by selecting a coolant with an appropriate freezing point.

In this embodiment, the coolant (a solution containing water and propylene glycol at 7% by volume) has been chosen to have a freezing point of about -2 C. This is cold enough to ensure that product is cooled enough so it can be dispensed at "extra cold" temperatures, but is not so cold that there is a danger of a product in the product coils 66 (e.g. beer) being frozen.

The maximum size of the ice bank 54 is determined by the thermostat. The thermostat is adapted to switch the refrigeration unit on (i.e. begin refrigeration) whenever the temperature detected by the temperature sensor 80 goes above a first predetermined threshold value and to switch it off when the detected temperature goes below a second threshold value. Lower threshold values will result in a larger ice bank 54, since the refrigeration unit will be switched off (i.e. refrigeration is stopped) at lower temperatures. Higher threshold values will result in a smaller ice bank 54, since the refrigeration unit will be switched off at higher temperatures.

A larger ice bank 54 improves the cooling capacity of the ice bank cooler 50, but decreases the space available for product coils 66. Conversely, a smaller ice bank 54 worsens the cooling capacity of the ice bank cooler 50, but increases the space available for product coils 66.

There is a temperature gradient within the ice bank 54, therefore the temperature detected by the temperature sensor 80 depends on where the temperature sensor is positioned. The threshold value required to produce a desired size of ice bank 54 therefore depends on the position of the temperature sensor 80 and should be set accordingly (e.g. by a technician) . The temperature sensor 80 is typically positioned to be within the ice bank 54 or at the boundary 58.

It has been found by measuring the refractive index of the ice bank 54 and the liquid part of the coolant 56 that, when the coolant 52 is a solution including freeze suppressant and water, the concentration of the freeze suppressant in the liquid part of the coolant 56 is higher than the concentration of the freeze suppressant in the ice bank 54. This means that the freezing point of the liquid part of the coolant 56 is lower than the freezing point of the ice bank 54, so the liquid part of the coolant 56 is less likely to freeze.

Fig. 4 shows the results from tests that have been carried out to compare the effectiveness of three different coolants. The three different coolants used in the tests were water (line 102), a solution containing water and 30% propylene glycol by volume (line 104), and a solution containing water and 7% propylene glycol by volume (line 106) . The graph 100 in Fig. 4 shows dispense temperature compared with the number of drinks dispensed (i.e. product dispensed) over the period of an hour for each coolant.

The tests were carried out under the same controlled conditions for each type of coolant, with the same cooling unit and coolant being used in each case. The cooling unit was filled to have a reservoir of 65 litres.

Water was used as the dispensed product in each case.

Some freeze suppressant was added to the water used as the dispensed product so that it could be cooled below 0 C. The ambient temperature in the dispense room was 24 C. The product input temperature to the cooling unit was 12 C. The dispense temperature of the product was measured using a calibrated thermocouple connected in the product lines at the point of dispense. Four product lines were used, each product line having a dispense rate of 1 pint per minute, giving an overall dispense rate of 4 pints per minute (240 pints per hour) . The dispense temperatures from each of the four product line were periodically measured and averaged to give the results shown in Fig. 4.

When water was used as the coolant (line 102), an ice bank was formed. Therefore, line 102 represents the results for a conventional ice bank cooler. As shown in the graph 100, the first few drinks are dispensed at about 3 C but this quickly increases to about 5-6 C as the load increases. Over the course of the hour, the dispense temperature was maintained at 5-6 C by the ice bank. Although dispensing temperatures of 5-6 C are suitable for some products, the conventional ice bank cooler is not suitable for delivering "extra cold" products at medium to high loads. In order to deliver "extra cold" products with a conventional ice bank cooler, a supplementary cooler must be used (e.g. the supplementary coolers 24 shown in Fig. 1) When a solution containing water and 30% propylene glycol was used as the coolant (line 104), no ice bank was formed because the freezing point of the coolant was too low. Therefore, line 104 represents a "glycol cooler". The propylene glycol was cooled to -2 C. Because the coolant has a low freezing point, very low dispensing temperatures of -2 C to -1 C (the initial temperature of the coolant) are achieved at relatively small numbers of drinks (less than about 25) . However, as the number of dispensed drinks increased, the dispensing temperature increased quickly due to the coolant warming up.

Therefore, "glycol coolers" are not suited to delivering large volumes of "extra cold" product. In practice, manufacturers tend to make "glycol coolers" with larger reservoirs or more powerful refrigeration units in order to increase their effectiveness at high loads, but this can be expensive to implement.

When a solution containing water and 7% propylene glycol was used as the coolant (line 106), an ice bank was formed. Therefore, line 106 represents the results for the ice bank cooler 50 illustrated in Figs. 2 and 3.

As can be seen from the graph 100, the dispense temperature was consistently maintained at around 1 C to 2 C even at high loads. It is thought the improved performance compared with the other types of cooler is due to the thermal capacity of the ice bank, combined with the low temperature of the liquid part of the coolant. Therefore, the ice bank cooler 50 is suitable for delivering large volumes of "extra cold" drinks.

Fig. 5a illustrates a cooler (with a 34cc compressor) with a full ice bank created when water is used as the coolant. Fig. 5b illustrates the same cooler with a full ice bank created when a solution containing water and 7% propylene glycol is used as the coolant.

One of ordinary skill after reading the foregoing description will be able to affect various changes, alterations, and subtractions of equivalents without departing from the broad concepts disclosed. It is therefore intended that the scope of the patent granted hereon be limited only by the appended claims, as

interpreted with reference to the description and

drawings, and not by limitation of the embodiments described herein.

Claims

Claims 1. An ice bank cooler having: a reservoir of coolant; and a

refrigeration unit including a refrigeration pipe for circulating a refrigerant therein, a portion of the refrigeration pipe being in the coolant for forming an ice bank from the coolant thereon; wherein the freezing point of the coolant is below the freezing point of water and above the operating temperature of the refrigerant.
2. An ice bank cooler according to claim 1 having a thermostat which includes: a temperature sensor in the coolant for detecting the temperature of the coolant; and a controller for controlling the refrigeration unit according to the sensed temperature of the coolant, to regulate the temperature of the coolant and the size of the ice bank when the ice bank cooler is in use.
3. An ice bank cooler according to claim 2 wherein the thermostat is adapted to switch on the refrigeration unit when the detected temperature goes above a first threshold value and switch off the refrigeration unit when the detected temperature goes below a second threshold value.
4. An ice bank cooler according to any one of the previous claims wherein the portion of the refrigeration pipes in the coolant is coiled.
5. An ice bank cooler according to any one of the previous claims including one or more product pipes for carrying a product to be cooled, a portion of the one or more product pipes being in the coolant.
6. An ice bank cooler according to claim 5 wherein the portion of each product pipe in the coolant is coiled.
7. An ice bank cooler according to any one of the previous claims including a pump for circulating coolant around a python.
8. An ice bank cooler according to claim 7 wherein the pump is adapted to agitate the reservoir of coolant.
9. An ice bank cooler according to any one of the previous claims including an agitation device for agitating the reservoir of coolant.
10. An ice bank cooler according to any one of the previous claims wherein at least some of the coolant is in the liquid phase.
11. An ice bank cooler according to any one of the previous claims wherein the operating temperature of the refrigerant is in the range -15 C to -SOC.
12. An ice bank cooler according to any one of the previous claims wherein the freezing point of the coolant is higher than -5 C.
13. An ice bank cooler according to claim 12 wherein the freezing point of the coolant is higher than -3 C.
14. An ice bank cooler according to any one of the previous claims wherein the freezing point of the coolant is lower than _100.
15. An ice bank cooler according to any one of the previous claims wherein the coolant is a solution which includes water and a freeze suppressant.
16. An ice bank cooler according to claim 15 wherein the freeze suppressant is propylene glycol.
17. An ice bank cooler according to claim 16 wherein the solution includes propylene glycol. in a concentration of 0% to 10% by volume.
18. An ice bank cooler according to claim 17 wherein the solution includes propylene glycol in a concentration of 5% to 10% by volume.
19. An ice bank cooler according to claim 18 wherein the solution includes propylene glycol in a concentration of 6% to 8% by volume.
20. An ice bank cooler according to any one of claims 15 to 19 wherein the freeze suppressant is not toxic to humans.
21. An ice bank cooler substantially as herein described, with reference to and as shown in the accompanying drawings. * ** * S * * S. S.,. * . S. * . * *5 5.

S *S*S *S * *5

S

21. An ice bank cooler according to any one of the previous claims wherein the coolant includes a corrosion inhibitor.

22. A system for dispensing cooled drinks including: an ice bank cooler according to any one of the previous claims; and one or more dispensers for dispensing product, the dispensers being in fluid communication with the one or more product pipes.

23. A method of modifying an ice bank cooler including: creating a reservoir of coolant in the ice bank cooler by filling it with a coolant as set out in any one of the previous claims.

24. An ice bank cooler substantially as herein described, with reference to and as shown in the accompanying drawings.

Amendments to the claims have been filed as follows Claims 1. An ice bank cooler having: a reservoir of coolant, the coolant being a solution which includes water and propylene glycol; a refrigeration unit including a refrigeration pipe for circulating a refrigerant therein, a portion of the refrigeration pipe being in the coolant for forming an ice bank from the coolant thereon; and one or more product pipes for carrying a product to be cooled, a portion of the one or more product pipes being in the coolant; wherein the freezing point of the coolant is below *:*::* the freezing point of water and above the operating * S temperature of the refrigerant. S. *. * S..

* 2. An ice bank cooler according to claim 1 having a S...

: thermostat which includes: 0SS a temperature sensor in the coolant for detecting the temperature of the coolant; and a controller for controlling the refrigeration unit according to the sensed temperature of the coolant, to regulate the temperature of the coolant and the size of the ice bank when the ice bank cooler is in use.

3. An ice bank cooler according to claim 2 wherein the thermostat is adapted to switch on the refrigeration unit when the detected temperature goes above a first threshold value and switch off the refrigeration unit when the detected temperature goes below a second threshold value.

4. An ice bank cooler according to any one of the previous claims wherein the portion of the refrigeration pipes in the coolant is coiled.

5. An ice bank cooler according to any one of the previous claims wherein the portion of each product pipe in the coolant is coiled. S... * * S...

6. An ice bank cooler according to any one of the S..

* previous claims including a pump for circulating coolant

SI

: around a python. S..

7. An ice bank cooler according to claim 6 wherein the pump is adapted to agitate the reservoir of coolant.

8. An ice bank cooler according to any one of the previous claims including an agitation device for agitating the reservoir of coolant.

9. An ice bank cooler according to any one of the previous claims wherein at least some of the coolant is in the liquid phase.

10. An ice bank cooler according to any one of the previous claims wherein the operating temperature of the refrigerant is in the range -15 C to -5 C.

11. An ice bank cooler according to any one of the previous claims wherein the freezing point of the coolant is higher than -5 C.

12. An ice bank cooler according to claim 11 wherein the freezing point of the coolant is higher than -3 C. S... * * ** S

13. An ice bank cooler according to any one of the previous claims wherein the freezing point of the coolant *..S : is lower than -1 C. * ** S

14. An ice bank cooler according to any previous claim wherein the coolant solution includes propylene glycol in a concentration of 0% to 10% by volume.

15. An ice bank cooler according to claim 14 wherein the solution includes propylene glycol in a concentration of 5% to 10% by volume. 32.

16. An ice bank cooler according to claim 15 wherein the solution includes propylene glycol in a concentration of 6% to 8% by volume.

17. An ice bank cooler according to any one of the previous claims 15 wherein the freeze suppressant is not toxic to humans.

18. An ice bank cooler according to any one of the previous claims wherein the coolant includes a corrosion inhibitor.

*... 19. A system for dispensing cooled drinks including: S...

an ice bank cooler according to any one of the previous claims; and S..

one or more dispensers for dispensing product, the S...

dispensers being in fluid communication with the one or

S

more product pipes.

20. A method of modifying an ice bank cooler including: creating a reservoir of coolant in the ice bank cooler by filling it with a coolant as set out in any one of the previous claims.