[0001] The present disclosure relates to the technical field of refrigeration systems. In particular, the present disclosure pertains to a milk cooler that cools the milk instantly, thereby reducing time between receipt of bulk milk and attaining storage temperature.
BACKGROUND
[0002] Background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
[0003] Existing bulk milk coolers are designed to cool the milk to 4°C, from 35°C at which it leaves udder, within a specified time period. In order to minimize microorganism growth, it is desirable that milk, after it is received for storage, is cooled to 4°C as rapidly as possible. A faster cooling, however, requires high refrigeration capacity, which may not be utilized after the milk has attained storage temperature of 4°C.
[0004] Within these limitations, the bulk milk coolers (BMC) are designed to cool collection amount in three hours duration, wherein the collection amount is taken as half of total capacity of the BMC. This is so in view of two milk collection durations- morning and evening. However, often times, a milk collection center may obtain more than V2 of the capacity of the tank, and in that case, the cooling capacity provided in the BMC is not able to provide cooling within the requisite 3 hours.
[0005] Furthermore, in many parts of the world, the grid power supply is not reliable, and to avoid spoilage of milk, collection centers have to depend on diesel generator sets to run the refrigeration system. This increases cost of storage of milk. Alternatively, if a solar photovoltaic panel is used, there is no power available in off solar hours, i.e. during evenings, nights and early mornings.
[0006] Therefore, there is a need to provide an improved milk cooling system, which can rapidly chill desired quantity of milk to a desired temperature thereby reducing overall bacteria growth and enhancing value of the milk. It would be additionally beneficial if the improved bulk milk cooler also removes dependence on diesel generator sets by providing back up cooling capability to chill the milk to a desired temperature, even when grid supply is interrupted.

[0007] All publications herein are incorporated by reference to the same extent as if each individual publication or patent application were specifically and individually indicated to be incorporated by reference. Where a definition or use of a term in an incorporated reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply. [0008] In some embodiments, the numbers expressing quantities of ingredients, properties such as concentration, reaction conditions, and so forth, used to describe and claim certain embodiments of the invention are to be understood as being modified in some instances by the term "about." Accordingly, in some embodiments, the numerical parameters set forth in the written description and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by a particular embodiment. In some embodiments, the numerical parameters should be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of some embodiments of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as practicable. The numerical values presented in some embodiments of the invention may contain certain errors necessarily resulting from the standard deviation found in their respective testing measurements.
[0009] As used in the description herein and throughout the claims that follow, the meaning of "a," "an," and "the" includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of "in" includes "in" and "on" unless the context clearly dictates otherwise.
[0010] The recitation of ranges of values herein is merely intended to serve as a shorthand method of referring individually to each separate value falling within the range. Unless otherwise indicated herein, each individual value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g. "such as") provided with respect to certain embodiments herein is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention otherwise claimed. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the invention.
[0011] Groupings of alternative elements or embodiments of the invention disclosed herein are not to be construed as limitations. Each group member can be referred to and

claimed individually or in any combination with other members of the group or other elements found herein. One or more members of a group can be included in, or deleted from, a group for reasons of convenience and/or patentability. When any such inclusion or deletion occurs, the specification is herein deemed to contain the group as modified thus fulfilling the written description of all Markush groups used in the appended claims.
OBJECTS OF THE INVENTION
[0012] A general object of the present disclosure is to provide a cost effective system for
storage of bulk milk from the time of its receipt till it is taken up for further processing or
consumption.
[0013] An object of the present disclosure is to provide a cost effective set up for storage
of bulk milk that includes a milk cooling system that improves value of milk by minimizing
microorganism growth.
[0014] Another object of the present disclosure is to provide a milk cooling system and
method that minimizes microorganism growth by rapidly chilling a desired quantity of milk
to a temperature at which microorganism growth is slowed down.
[0015] Another object of the present disclosure is to provide a milk cooling system and
method that rapidly chills milk without increase in capacity of the associated cooling plant.
[0016] Another object of the present disclosure is to provide a milk cooling system and
method that rapidly chills milk using cooling capacity that is surplus during lean period,
when cooling demand for cooling the stored milk is low or zero.
[0017] Another object of the present disclosure is to provide a milk cooling system and
method that reduces dependence on backup power source to meet the exigencies of grid
power failure.
[0018] Yet another object of the present disclosure is to provide a milk cooling system
and method with backup cooling capacity so that dependence on backup power source is
eliminated.
[0019] Still another object of the present disclosure is to provide a milk cooling system
and method that reduces expenses on account of power consumption.
SUMMARY
[0020] Aspects of the present disclosure relate to storage of bulk milk from the time of
its receipt till it is taken up for further processing or consumption. In particular, the present disclosure relates to an improved milk cooling system and method used with bulk milk

storage systems. The improved milk cooling system and method enable instant cooling of the bulk milk, on receipt, to a desired temperature required to slow down growth of microorganisms that may happen during the period between receipt of bulk milk and its cooling to preservation temperature that is absolutely must to prevent microorganism growth. [0021] In an aspect, the disclosed cooling system and method achieve the reduction in cooling time without increase in cooling capacity (i.e. tonnage) of the associated refrigeration system. This is done by storing surplus cooling capacity during lean period, by cooling and storing a media in a thermal storage battery. The stored cooling capacity is used to instantly cool the milk, at the time of receipt, to the desired temperature, through a heat exchanger. [0022] In an aspect, the disclosedmilk cooling system comprises a milk dump tank to receive milk supply; a bulk milk cooler that receives milk from the milk dump tank, and is configured to cool and store the milk below the preservation temperature (also referred to as first desired temperature);at least one condensing unit; a thermal storage battery; and a heat exchanger provided in flow path of milk from the milk dump tank to the bulk milk cooler. [0023] In an aspect, the heat exchanger is adapted to instantly cool the milk below a desired temperature required to slow down growth of microorganisms (referred to as a second desired temperature) that is higher than the first desired temperature.
[0024] In an aspect, the heat exchanger is fiuidly coupled to the heat exchanger to circulate a cooling media through the heat exchanger to instantly cool the milk below the second desired temperature.
[0025] In an aspect, the milk cooling system comprises at least one refrigerant circuit to selectively circulate a refrigerant between the at least one condensing unit and the bulk milk cooler, between the at least one condensing unit and the thermal storage battery, and between the thermal storage battery and the bulk milk cooler.
[0026] In an aspect, the least one refrigerant circuit may incorporate a pump to circulate the refrigerant between the thermal storage battery and the bulk milk cooler. [0027] In an embodiment, the at least one condensing unit may comprise two condensing units, such as a first condensing unit and a second condensing unit; and the first condensing unit may be fiuidly coupled to the thermal storage battery by a first refrigerant circuit, and the second condensing unit may be fiuidly coupled to the bulk milk cooler by a second refrigerant circuit.
[0028] In an aspect, the milk cooling system may comprise a controller to selectively circulate the refrigerant between the at least one condensing unit and the bulk milk cooler, between the at least one condensing unit and the thermal storage battery, and between the

thermal storage battery and the bulk milk cooler; and to circulate the cooling media between
the thermal storage battery and the heat exchanger, when required.
[0029] In an aspect, the controller may be configured to selectively circulate the cooling
media between the thermal storage battery and the heat exchanger when flow of milk from
the milk dump tank to the bulk milk cooler is detected.
[0030] In an aspect, the controller may be configured to circulate the refrigerant between
the thermal storage battery and the bulk milk cooler when there is no grid power supply.
[0031] In an aspect, the controller may be configured to circulate the refrigerant between
the at least one condensing unit and the thermal storage battery during night and afternoon
when load to cool the milk in the bulk milk cooler is low or zero.
[0032] In an aspect, the heat exchanger may be a plate type heat exchanger that is adapted
to cool milk below the second desired temperature as the milk flows through the heat
exchanger.
[0033] In an aspect, the cooling media may be same as storage media used in the thermal
storage battery. In an aspect, the storage media may be a phase change material that freezes
when cooled, thereby storing the cooling capacity and liquid phase of the storage media may
be used as the cooling media and circulated through the heat exchanger. In an aspect, water
may be used as the cooling media/thermal storage media.
[0034] In an aspect, the second desired temperature may be chosen to slow down
microorganism growth in the milk during the period until the milk attains the first desired
temperature.
[0035] In an aspect, the first desired temperature may be 4°C and the second desired
temperature may be 8°C. In preferred embodiments, the bulk milk cooler may maintain milk
at temperature in the range of 3- 5°C and the heat exchanger may instantly cool the milk to
temperature in the range of 5-10°C.
[0036] In an aspect, the present disclosure also relates to a method for cooling milk to
prevent growth of microorganism, the proposed method comprising steps of: (a) providing a
heat exchanger in milk flow path between a milk dump tank and a bulk milk cooler of a milk
cooling system; (b) providing a thermal storage battery in the milk cooling system; (c)
charging the thermal storage battery by circulating a refrigerant from at least one condensing
unit of the milk cooling system through the thermal storage battery; and (d) cooling milk,
when being transferred from the milk dump tank to the bulk milk cooler, to a temperature
below 8°C, by circulating a cooling media between the heat exchanger and the thermal
storage battery.
6

[0037] In an aspect, the method may comprise cooling and maintaining the milk in the
bulk milk cooler, at temperature below 4°C, by circulating the refrigerant through bulk milk
cooler from the at least one condensing unit.
[0038] In an aspect, the method may comprise cooling and maintaining the milk in the
bulk milk cooler, at temperature below 4°C, when grid power is not available, by circulating
the refrigerant between the bulk milk cooler and the thermal storage battery.
[0039] In an aspect, the step of charging the thermal storage battery may be carried out
during night and afternoon when load to cool the milk in the bulk milk cooler is low or zero.
BRIEF DESCRIPTION OF THE DRAWINGS
[0040] The accompanying drawings are included to provide a further understanding of
the present disclosure, and are incorporated in and constitute a part of this specification. The
drawings illustrate exemplary embodiments of the present disclosure and, together with the
description, serve to explain the principles of the present disclosure.
[0041] FIG. 1 illustrates a layout of a typical milk cooling system used for storing bulk
supply of milk to prevent spoilage.
[0042] FIG. 2A illustrates an exemplary graph showing comparison of rate of cooling of
the proposed instant milk cooling system as compared to a conventional milk cooling system,
in accordance with an embodiment of the present disclosure.
[0043] FIG. 2B illustrates an exemplary schematic representation of the proposed instant
milk cooling system, in accordance with embodiments of the present disclosure.
[0044] FIGs. 3A to 3E are exemplary layouts showing working of the proposed instant
milk cooling system under different modes, in accordance with embodiments of the present
disclosure.
[0045] FIGs. 4A to 4C are exemplary layouts showing the proposed instant milk cooling
system with two condensing units working under different modes, in accordance with
embodiments of the present disclosure.
[0046] FIGs. 5A to 5B are exemplary side view and perspective view of a thermal storage
battery of first kind used in the proposed instant milk cooling system, in accordance with
embodiments of the present disclosure.
[0047] FIG. 6 is an exemplary side view of a thermal storage battery of second kind used
in the proposed instant milk cooling system, in accordance with embodiments of the present
disclosure.
7

[0048] FIG. 7 is an exemplary flow diagram for the proposed method for instant milk cooling, in accordance with embodiments of the present disclosure.
DETAILED DESCRIPTION
[0049] The following is a detailed description of embodiments of the disclosure depicted
in the accompanying drawings. The embodiments are in such detail as to clearly
communicate the disclosure. However, the amount of detail offered is not intended to limit
the anticipated variations of embodiments; on the contrary, the intention is to cover all
modifications, equivalents, and alternatives falling within the spirit and scope of the present
disclosure as defined by the appended claims.
[0050] Each of the appended claims defines a separate invention, which for infringement
purposes is recognized as including equivalents to the various elements or limitations
specified in the claims. Depending on the context, all references below to the "invention"
may in some cases refer to certain specific embodiments only. In other cases it will be
recognized that references to the "invention" will refer to subject matter recited in one or
more, but not necessarily all, of the claims.
[0051] Various terms as used herein are shown below. To the extent a term used in a
claim is not defined below, it should be given the broadest definition persons in the pertinent
art have given that term as reflected in printed publications and issued patents at the time of
filing.
[0052] Embodiments explained herein relate to a milk cooling system and method that
substantially reduces time to cool bulk supply of milk to a temperature required to prevent
growth of microorganisms. In an aspect, reduction in cooling time is achieved without
increase in cooling capacity (i.e. tonnage) of the associated refrigeration system.
[0053] Conventional bulk milk cooling systems, as shown in FIG. 1, incorporate a
storage tank 20 (also referred to as bulk milk cooler) in which bulk milk supply is poured.
The storage tank 20 includes a cooling coil that receives a refrigerant to cool the stored milk.
The cooling coil is part of a refrigeration circuit having an outdoor unit 30 (which includes a
compressor and a condenser, and the outdoor unit also referred to as condensing unit
hereinafter), a service valve 33 and an expansion valve 42.
[0054] The conventional bulk milk cooling systems are designed to cool a given amount
of milk below 4°C to prevent growth of microorganisms, within a specified time period so
that spoilage of milk due to growth of microorganism during the intervening period is
avoided. However, in case there is power interruption, or if quantity of milk received is more,
8

the time to cool the milk to the desired temperature shall increase, increasing the risk of growth of microorganism leading to spoilage of the milk.
[0055] In an aspect, the present disclosure overcomes the above stated limitations by providing a system that instantly cools the bulk milk to a lower temperature (Referred to as a second desired temperature, which may be higher than the preservation temperature, such as in a range of 5-10°C) to slow down microorganism growth. In an aspect, bulk milk on receipt is made to flow through a heat exchanger, such as a plate type heat exchanger, where the milk is chilled to a temperature below 8°C. Thus, the bulk milk supply reaches the storage tank/bulk milk cooler at substantially lower temperature, and requires substantially reduced time to be cooled below 4°C. Also, growth of microorganism at temperatures below 8°C is considerably reduced.
[0056] FIG. 2A shows a comparison of cooling rate of the proposed instant milk cooling system as compared to a conventional milk cooling system. As shown therein by cooling curve 202, a conventional milk cooling system, such as cooling system of FIG. 1, takes about 250 minutes to cool milk to below 4°C. As against this, as shown by cooling curve 204, the proposed milk cooling system incorporating a heat exchanger for instant chilling of milk takes less than 100 minutes to cool milk to below 4°C. Cooling curve 204 also shows instant cooling of milk to about 5°C, which is achieved by the heat exchanger.
[0057] As can be appreciated by those skilled in art, instant cooling of bulk milk would require large cooling capacity, which if met by conventional refrigeration system would require increasing capacity of the refrigeration system at considerable investment, making the cooling system uneconomical. Besides, since instant chilling is required only when bulk milk supply is received, large refrigeration capacity would be underutilized rest of the time. [0058] In an aspect, the proposed instant milk cooling system incorporates a thermal storage battery, (also referred to as thermal storage or thermal battery or ice tank and all these terms used interchangeably hereinafter), to meet instant cooling requirement. A cooling media, such as water, is circulated through the thermal storage battery and the heat exchanger, when bulk supply of milk is poured into the storage tank through the heat exchanger.
[0059] FIG. 2B shows schematic representation of the proposed instant milk cooling system 200, comprising a heat exchanger 202, a milk storage tank/bulk milk cooler 20, a condensing unit 30, a thermal storage battery10, a milk dump tank 204 and pumps 206 and 208. When bulk milk is poured in the milk dump tank 204, the pump 208 moves to the milk to the milk storage tank/bulk milk cooler 20 through the heat exchanger 202. Simultaneously,
9

the pump 206 circulates the cooling media, i.e. water, through the thermal storage battery10 and the heat exchanger 202. As the milk flows through the heat exchanger 202, it gets cooled to a temperature below 8°C. Therefore, bulk milk reaches the bulk milk cooler 20 at substantially lower temperature than in case of conventional systems, where milk is received in the bulk milk cooler 20 at 35°C. Milk stored in the bulk milk cooler 20 is further cooled to below 4°C, and maintained at that temperature, by cooling through a refrigerant loop from the condensing unit 30.
[0060] In an aspect, milk stored in the bulk milk cooler 20 can also be cooled to below 4°C, and/or maintained at that temperature, by cooling through a refrigerant loop from the thermal battery 10. This can be helpful when the condensing unit 30 is not working on account of interruption in grid or solar power. Thus, requirement of power backup using a diesel generating set or solar panels can be dispensed with.
[0061] In an aspect, the thermal storage battery 10 can be recharged through a refrigeration loop from the condensing unit 30, when the milk stored in the bulk milk cooler 20 is already at temperature below 4°C and requires cooling only to maintain it at that temperature. This can be during night and afternoons when cooling demand on the condensing unit is low or zero.
[0062] In an aspect, the thermal storage battery 10 may work based on a storage media that is cooled by circulating the refrigerant from the condensing unit 30. The storage media may be a phase change material that freezes when cooled, and liquid phase of the storage media may be used as the cooling media and circulated through the heat exchanger 202 by the pump 206. As the cooling media/liquid phase of the storage media circulates through the heat exchanger 202, being at lower temperature, is absorbs heat from milk to cool the milk. On return to the thermal storage battery 10 the cooling media/liquid phase of the storage media transfers that heat to the solid phase storage media, which may convert to liquid phase by absorbing heat from the liquid phase to maintain the liquid phase at a low temperature. [0063] In an aspect, the storage media may be a material with high latent heat for conversion between liquid and solid phase, known as heat of fusion, and a liquid-solid phase change temperature lower that 8°C so that its liquid phase is able to cool milk in the heat exchanger to temperature below 8°C. In a preferred embodiment, water which has phase change temperature of 0°C and latent heat of fusion of 334 joules (79.7 calories) per gram. [0064] Following table compares operating as well as commercial aspects of the disclosed bulk milk cooling system such as system 200 of FIG. 2B, with a conventional
10

system of equivalent size. As can be seen from the comparison, a system incorporating the proposed concept provides considerable benefit over the conventional systems.

1000 Liter Bulk Milk Cooler 1000 Liter Bulk Milk Cooler with Diesel Generator Set with Thermal Storage battery
Milk Cooling Qty. 750 L/shift 750 L/shift
Sanctioned Load 5kW,single phase Requirement 5kW,single phase
Diesel Genset Size 15 kVA Not Required
Minimum Power Availability Required No minimum requirement 8 hrs/day
Capital Expenditure 5.5 Lakhs 6 Lakhs
Time for which Milk is exposed to higher than 7 °C 210 mins 0 mins
Operating expenses (Presuming 12 hrs/day Power Cut) 3.5 Lakhs/yr. 0.9 Lakhs/yr.
Table:Comparison of the proposed bulk milk cooling system with a conventional system of equivalent size.(based on diesel price of 70 INR/L; electricity price of 8 INR/kWh)
[0065] In an aspect, the heat exchanger 202 and the thermal storage 10 along with requisite refrigeration loops can be retrofitted in existing conventional milk cooling systems to reduce risk of spoilage of milk on account of longer cooling time in the conventional systems and to eliminate their dependence on captive diesel generating sets. [0066] FIGs. 3A to 3E show, through layouts, various working modes of the proposed instant milk cooling system 200. Different modes of operation of the system 200 involves routing refrigerant from the condensing unit 30 to one or more of the thermal storage 10 and the bulk milk cooler 20; and/or circulation of cooling media from the thermal battery 10 to one or more of the heat exchanger 202 and the bulk milk cooler 20, depending on requirement. Flow of refrigerant and the cooling media can be controlled and regulated by means of a number of valves configured in the refrigerant loops/cooling media loops, such as valves 36, 38, 46 and 52. There can also be a plurality of pumps such as pump 48 to help
11

circulate the refrigerant /cooling media, and expansion valves such as expansion valves 42
and 44 (refer to FIGs. 3A – 3E)
[0067] FIG. 3A shows working of the proposed bulk milk cooling system 200 in a mode
wherein milk stored in the bulk milk cooler 20 is being cooled by circulating the refrigerant
40 through the condensing unit 30 expansion valve 42 and the bulk milk cooler 20. The
thermal storage 10 is not being used in this mode.
[0068] FIG. 3B shows working of the proposed bulk milk cooling system 200 in a mode
wherein thermal storage 10 is being charged by routing the refrigerant 40 through the thermal
storage 10. The refrigerant flows through the condensing unit 30, the storage tank 34, the
valve 38, the expansion valve 44, the thermal storage 10 and the valve 52.
[0069] FIG. 3C shows working of the proposed bulk milk cooling system 200 in a mode
whereinthe thermal storage 10 is being used for instant cooling of milk. Milk 302 poured in
the milk dump tank 204 flows through the heat exchanger 202, and simultaneously a cooling
media 304 circulates between the thermal storage 10 and the heat exchanger 202 to instantly
cool the milk 302 to below 8°C. From the heat exchanger 202, milk flows to the bulk milk
cooler 20. Flow of milk is facilitated by pump 208 (refer to FIG. 2B).
[0070] FIG. 3D shows working of the proposed bulk milk cooling system 200 in a mode
wherein the thermal storage 10 is being used for instant cooling of milk 302, and
simultaneously, milk stored in the bulk milk cooler 20 is being cooled through the
condensing unit 30. Instant cooling of milk 302 is done in same manner as in FIG. 3C, and
for cooling the milk stored in the bulk milk cooler 20, refrigerant 40 is circulated between the
condensing unit 30 and the bulk milk cooler 20 through the valve 36 and the expansion coil
42.
[0071] FIG. 3E shows working of the proposed bulk milk cooling system 200 in a mode
wherein the thermal storage is being used for instant cooling of milk 302 as well as for
cooling the milk stored in the bulk milk cooler 20. Instant cooling of milk 302 is done in
same manner as in FIG. 3C, and for cooling the milk stored in the bulk milk cooler 20,
refrigerant 40 is circulated between the thermal storage 10 and the bulk milk cooler 20
through the pump 48 and the valves 52 and 46.
[0072] It can be seen from FIGs. 3B and 3E that the refrigerant loop through the thermal
storage 10 is used both for charging the thermal storage 10 by circulating the refrigerant from
the condensing unit 30, as well as for cooling milk stored in the bulk milk cooler 20 by
circulating the refrigerant from the thermal storage 10 to the bulk milk cooler 20.
12

[0073] In an implementation of the inventive concept of the present discosure, there can be two condensing units, one for cooling milk in the bulk milk cooler 20 and other for charging the thermal battery 10. Inclusion of two condensing units provides redundancy wherein if one were to fail or under maintenance, other can meet both the requirements, i.e. of cooling milk in the bulk milk cooler 20 as well as of charging the thermal battery 10. [0074] FIGs. 4A to 4C show through layouts various working modes of the alternate embodiment of the instant milk cooling system 400 having two condensing units, such as a first condensing unit 30-1 and a second condensing unit 30-2 (collectively referred to as condensing unit 30), wherein FIG. 4A shows working of the proposed bulk milk cooling system 400 in a mode in which the thermal storage 10 is charged by routing the refrigerant 40 through the thermal storage 10. The refrigerant 40 flows through the first condensing unit 30-1, the storage tank 34, the valve 38, the expansion valve 44, the thermal storage 10 and the valve 52.
[0075] FIG. 4B shows working of the proposed bulk milk cooling system 400 in a mode in which the thermal storage 10 is being used for instant cooling of milk 302, and simultaneously, milk stored in the bulk milk cooler 20 is being cooled through the second condensing unit 30-2. Milk 302 poured in the milk dump tank 204 flows through the heat exchanger 202, and simultaneously a cooling media 304 circulates between the thermal storage 10 and the heat exchanger 202 to instantly cool the milk 302 to below 8°C. From the heat exchanger 202 milk flow to the bulk milk cooler 20. Flow of milk is facilitated by pump 208. For cooling the milk stored in the bulk milk cooler 20, refrigerant 40 is circulated between the second condensing unit 30-2 and the bulk milk cooler 20 through the valve 33 and the expansion coil 42.
[0076] FIG. 4C shows working of the proposed bulk milk cooling system 400 in a mode in which thethermal storage 10 is being used for instant cooling of milk 302, and simultaneously being charged by the first condensing unit 30-1. Milk stored in the bulk milk cooler 20 is also being cooled through the second condensing unit 30-2. Thus both the first condensing unit30-1and the second condensing unit30-2 work simultaneously. [0077] As can be understood by those skilled in the art, though FIGs. 4A -4C show working of the bulk milk cooling system 400 with the two condensing units 30 being dedicated for cooling the bulk milk cooler 20 and for charging the thermal storage 10 respectively, it is possible to configure refrigerant loops such that any one of the two condensing units 30 can meet both the requirements, thereby providing redundancy wherein if one were to fail or under maintenance, other can meet both the requirements.
13

[0078] It is to be appreciated that though embodiments illustrated in FIGs. 2B - 4C have been explained with reference to certain temperature values, such as 4°C and 8°C, the disclosed inventive concept can be applied for any other temperature values, and all such variations are well within the scope of the present disclosure without any limitations whatsoever.
[0079] In an aspect, the disclosed milk cooling system 200/400 can also incorporate a controller (not shown in the FIGs.) to selectively circulate the refrigerant 40 between the at least one condensing unit 30 and the bulk milk cooler 20, between the at least one condensing unit 30 and the thermal storage battery 10, and between the thermal storage battery 10 and the bulk milk cooler 20. Depending on requirement. The controller can also be configured to circulate the cooling media 304 between the thermal storage battery and the heat exchanger, when required.
[0080] For example, in an embodiment, the controller may be configured to circulate the cooling media 304 between the thermal storage battery and the heat exchanger when flow of milk from the milk dump tank 204 to the bulk milk cooler 20 is detected. [0081] In an embodiment, the controller may be configured to circulate the refrigerant 40 between the thermal storage battery 10 and the bulk milk cooler 20 when there is no grid power supply. Thus, dependence on backup power source to maintain temperature of milk is obviated.
[0082] In an embodiment, the controller may be configured to circulate the refrigerant 40 between the at least one condensing unit 30 and the thermal storage battery 10 during night and afternoon when there is no load on condenser to cool the milk in the bulk milk cooler 20, or load is low either due to low ambient temperature or because milk has already been cooled below the first desired temperature and only needs to be maintained at that temperature. Therefore, existing cooling capacity of the condensing unit 30 that lies idle during lean period, is used to cool a media, which is used for instant cooling of milk, and to maintain temperature of stored milk in the bulk milk cooler 20 when there is no grid power. [0083] An embodiment of the present disclosure provides the thermal storage 10, wherein the thermal storage 10, also referred to as ice tank, comprises two tanks, one inside the other. Double tank construction ensures sufficient travel distance for the cooling media to come in contact with ice to get cooled. The incoming warm cooling media from the heat exchanger 202 comes back in the inner tank which then travels to bottom side of the inner tank to get into the outer tank. During its travel in the inner tank and thereafter in the outer tank it gets cooled before it goes out to the heat exchanger 202.
14

[0084] FIGs. 5A to 5B are side view and perspective view of a thermal storage battery 10 of first kind used in the proposed instant milk cooling system, wherein the thermal storage battery 10 of first kind incorporates perforations at lower end of the inner tank 108. The cooling media 304 coming from the heat exchanger 202 through inlet pipe 105, enters the inner tank 108 where it comes in contact with ice and gets cooled. It moves down and exits the inner tank 108 through the apertures at bottom of the inner tank 108 to enter the outer tank. From the outer tank the cooled cooling media 304 moves to the heat exchanger 202 through outlet pipe 106.
[0085] FIG. 6 shows a side view of a thermal storage battery of second kind where inner tank 108 is placed higher than the bottom of the outer tank to provide space for the cooling media to move out of the inner tank to the outer tank.
[0086] It is to be appreciated that while FIGs. 5A to 6 show two types of thermal storage batteries, many other types, including those having different flow paths for the cooling media, can be used in the proposed system without any limitations whatsoever.
[0087] FIG. 7 is an exemplary method flow diagram for a method 700 for cooling milk to prevent microorganism growth. The method 700 comprises, at step 702, providing a heat exchanger, such as heat exchanger202 shown in FIGs. 2B to 4C, in milk flow path between milk dump tank, such as milk dump tank 204 shown in FIGs. 2B to 4C, and a bulk milk cooler, such as bulk milk cooler 20shown in FIGs. 2B to 4C, of a milk cooling system. At step 704 of the method 700, a thermal storage battery (also referred to as thermal storage), such as thermal storage battery 10 as shown in FIGs. 2Bto 4C, is provided in the milk cooling system. The thermal storage battery 10 is fluidly coupled to the heat exchanger 202 to enable circulation of a cooling media between the thermal storage battery 10 and the heat exchanger 202.
[0088] At step 706 of the method 700, the thermal storage battery 10 can be charged by circulating a refrigerant, such as refrigerant 40, between a condensing unit, such as condensing unit 30 of the cooling system, and the thermal storage battery 10, as shown in FIGs. 3B and 4A. At step 708 of the method 700, milk, when received, can be cooled to a temperature below 8°C as it flows from the milk dump tank 204 to the bulk milk cooler 20, by circulating a cooling media between the thermal storage battery 10 and the heat exchanger 202, as shown in FIGs. 3C, 3D, 3E, 4B and 4C. At step 710 of the method 700, the milk in the bulk milk cooler 20 can be further cooled to temperature below 4°C and maintained at that temperature, by circulating the refrigerant 40 between the bulk milk cooler 20 and the condensing unit 30, as shown in FIGs. 3A, 3D, 3E, 4B and 4C.
15

[0089] In alternate scenario, when the condensing unit 30 cannot be operated to cool and maintain temperature of the milk in the bulk milk cooler 20 below 4°C due to non-availability of grid power, step 712 of the method 700 can involve circulating the refrigerant 40 between the thermal battery 10 and the bulk milk cooler 20, as shown in FIG. 3E, to cool and maintain temperature of the milk in the bulk milk cooler 20 at temperature below 4°C. Thus, dependence of the milk cooling system on a backup power such as diesel generator or solar panels is obviated.
[0090] Thus, the present disclosure provides an improved bulk milk cooling system that cools milk to sub 4°C temperature much faster than in a conventional bulk milk cooling systems, thereby reducing the risk of the stored milk getting spoiled due to growth of microorganisms. The proposed system also does away with requirement of a diesel generator set as power back up to cater to grid power interruptions or during off solar hours. The thermal storage and heat exchanger that provide instant cooling of milk without increase in tonnage of the refrigeration system can be retrofitted in conventional bulk milk coolers. [0091] While the foregoing describes various embodiments of the invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof. The scope of the invention is determined by the claims that follow. The invention is not limited to the described embodiments, versions or examples, which are included to enable a person having ordinary skill in the art to make and use the invention when combined with information and knowledge available to the person having ordinary skill in the art.
ADVANTAGES OF THE INVENTION
[0092] The present disclosure provides a cost effective system for storage of bulk milk
from the time of its receipt till it is taken up for further processing or consumption.
[0093] The present disclosure provides a milk cooling system and method, during storage
of bulk milk, that improves value of milk by minimizing microorganism growth.
[0094] The present disclosure provides a milk cooling system and method that minimizes
microorganism growth by rapidly chilling a desired quantity of milk to a temperature at
which microorganism growth is slowed down.
[0095] The present disclosure provides a milk cooling system and method that rapidly
chills milk without increase in capacity of the associated cooling plant.
[0096] The present disclosure provides a milk cooling system and method that rapidly
chills milk using cooling capacity that is surplus during lean period, when cooling demand
for cooling the stored milk is low or zero.
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[0097] The present disclosure provides a milk cooling system and method that reduces
dependence on backup power source to meet the exigencies of grid power failure.
[0098] The present disclosure provides a milk cooling system and method with backup
cooling capacity so that dependence on backup power source is eliminated.
[0099] The present disclosure provides a milk cooling system and method that reduces
expenses on account of power consumption.

We Claim:

A milk cooling system comprising:
a milk dump tank to receive milk supply;
a bulk milk cooler that receives milk from the milk dump tank, and is configured to cool and store the milk below a first desired temperature;
at least one condensing unit;
a thermal storage battery; and
a heat exchanger provided in flow path of milk from the milk dump tank to the bulk milk cooler;
wherein the heat exchanger is adapted to instantly cool the milk below a second desired temperature that is higher than the first desired temperature; and wherein the heat exchanger is fiuidly coupled to the thermal storage battery to circulate a cooling media through the heat exchanger to instantly cool the milk. The milk cooling system as claimed in claim 1, comprising at least one refrigerant circuit to selectively circulate a refrigerant between the at least one condensing unit and the bulk milk cooler, between the at least one condensing unit and the thermal storage battery, and between the thermal storage battery and the bulk milk cooler. The milk cooling system as claimed in claim 2, wherein the least one refrigerant circuit incorporates a pump to circulate the refrigerant between the thermal storage battery and the bulk milk cooler.
The milk cooling system as claimed in claim 2, wherein the at least one condensing unit comprises a first condensing unit fiuidly coupled to the thermal storage battery by a first refrigerant circuit, and a second condensing unit fiuidly coupled to the bulk milk cooler by a second refrigerant circuit.
The milk cooling system as claimed in claim 4, comprising a controller to selectively circulate the refrigerant between the at least one condensing unit and the bulk milk cooler, between the at least one condensing unit and the thermal storage battery, and between the thermal storage battery and the bulk milk cooler; and to circulate the cooling media between the thermal storage battery and the heat exchanger, when required.
The milk cooling system as claimed in claim 5, wherein the controller is configured to circulate the cooling media between the thermal storage battery and the heat

exchanger when flow of milk from the milk dump tank to the bulk milk cooler is
detected.
The milk cooling system as claimed in claim 5, wherein the controller is configured to
circulate the refrigerant between the thermal storage battery and the bulk milk cooler
when there is no grid power supply.
The milk cooling system as claimed in claim 5, wherein the controller is configured to
circulate the refrigerant between the at least one condensing unit and the thermal
storage battery during night and afternoon when load to cool the milk in the bulk milk
cooler is low or zero.
The milk cooling system as claimed in claim 1, wherein the heat exchanger is a plate
type heat exchanger, and is adapted to cool milk below the second desired
temperature as the milk flows through the heat exchanger.
The milk cooling system as claimed in claim 1, wherein the cooling media is water.
The milk cooling system as claimed in claim 1, wherein the second desired
temperature is chosen to slow down microorganism growth in the milk during the
period until the milk attains the first desired temperature.
The milk cooling system as claimed in claim 11, wherein the first desired temperature
is 4°C and the second desired temperature is 8°C.
A method for cooling milk to prevent growth of microorganism, comprising:
providing a heat exchanger in milk flow path between a milk dump tank and a bulk milk cooler of a milk cooling system;
providing a thermal storage battery in the milk cooling system;
charging the thermal storage battery by circulating a refrigerant from at least one condensing unit of the milk cooling system through the thermal storage battery; and
cooling milk, when being transferred from the milk dump tank to the bulk milk cooler, to a temperature below 8°C, by circulating a cooling media between the heat exchanger and the thermal storage battery.
The method as claimed in claim 13, comprising: cooling and maintaining the milk in the bulk milk cooler, at temperature below 4°C, by circulating the refrigerant through bulk milk cooler from the at least one condensing unit.
The method as claimed in claim 13, comprising: cooling and maintaining the milk in the bulk milk cooler, at temperature below 4°C, when grid power is not available, by

circulating the refrigerant between the bulk milk cooler and the thermal storage
battery.
The method as claimed in claim 13, wherein the step of charging the thermal storage
battery is carried out during night and afternoon when load to cool the milk in the
bulk milk cooler is low or zero.