HEAT TREATING A DAIRY PRODUCT USING A HEAT PUMP

Abstract

A method for heating and cooling a consumable product disposed in a product container includes the steps of: (i) heating the consumable product to a first temperature by transferring heat from ambient air to refrigerant through a liquid-to-air heat exchanger; and (ii) heating the consumable product to a second temperature without transferring heat from the ambient air to the refrigerant through the liquid-to-air heat exchanger; wherein the second temperature is greater than the first temperature.

Description

This application claims priority to U.S. Provisional Appln. No. 61/251,091 filed Oct. 13, 2009, which is hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Technical Field

This disclosure relates generally to a heating and refrigeration system and, more particularly, to a system for heating a dairy product using a heat pump.

2. Background Information

Dairy heating and cooling (“H&C”) systems are used to prepare (e.g., mix, pasteurize and cool), store in a chilled environment and/or dispense dairy products such as soft serve ice cream and milk shakes. A typical dairy H&C system includes a dairy product heat exchanger thermally coupled to a container (e.g., a hopper or a freezing cylinder), a compressor, a condenser, an expansion valve and a hot gas solenoid valve. In a cooling cycle, the dairy product heat exchanger (e.g., operating as an evaporator), the compressor, the condenser and the expansion valve form a cooling loop. In a heating cycle, the dairy product heat exchanger (e.g., operating as a condenser), the compressor and the hot gas solenoid valve form a heating loop.

During the cooling cycle, the compressor directs refrigerant through the condenser and the expansion valve, and into the dairy product heat exchanger in a typical fashion. The dairy product within the container is chilled as heat transfers from the dairy product to the refrigerant. During the heating cycle, the compressor directs the refrigerant through the hot gas solenoid valve and into the dairy product heat exchanger bypassing the condenser. The dairy product within the container is heated (e.g., up to 150° Fahrenheit (“F”) for pasteurization) as heat transfers from the refrigerant to the dairy product.

The efficiency for the dairy H&C system can be determined by dividing the heat energy transferred into or out of the dairy product (i.e., “transferred heat energy”) by the respective electrical energy used to heat or cool the dairy product (i.e., “work energy”); that is

Efficiency≈(Transferred Heat Energy)/(Work Energy).

In the aforesaid heating cycle, the transferred heat energy is typically less than the work energy used to heat the dairy product since approximately all the heat energy is generated via the compressor. Thus, disadvantageously the dairy H&C system obtains a maximum efficiency of one or below.

SUMMARY OF THE DISCLOSURE

According to one aspect of the invention, a multi-phase heating system is provided that includes a product container, a product heat exchanger, a liquid-to-air heat exchanger, a compressor, and a system valve. The product heat exchanger selectively transfers heat into or out of the product container. The system valve selectively configures the system between a first heating loop and a second heating loop. The first heating loop extends through the product heat exchanger, the liquid-to-air heat exchanger and the compressor. The second heating loop extends through the product heat exchanger and the compressor, and bypasses the liquid-to-air heat exchanger.

According to another aspect of the invention, a heating and refrigeration system is provided that includes a product container, a product heat exchanger, an expansion valve, a liquid-to-air heat exchanger, a compressor, and a system valve. The product heat exchanger selectively transfers heat into or out of the product container. The system valve selectively configures the system between a cooling loop and heating loop. The cooling loop extends through the liquid-to-air heat exchanger, the expansion valve, the product heat exchanger and the compressor. The heating loop extends through the product heat exchanger, the expansion valve, the liquid-to-air heat exchanger and the compressor.

According to still another aspect of the invention, a method for heating and cooling a consumable product disposed in a product container is provided. The method includes the steps of: (i) heating the consumable product to a first temperature by transferring heat from ambient air to refrigerant through a liquid-to-air heat exchanger; and (ii) heating the consumable product to a second temperature without transferring heat from the ambient air to the refrigerant through the liquid-to-air heat exchanger; wherein the second temperature is greater than the first temperature.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatic illustration of a multi-phase system selectively configured in a first heating loop.

FIG. 2 is a diagrammatic illustration of the multi-phase system of FIG. 1 selectively configured in a second heating loop.

FIG. 3 is a diagrammatic illustration of the multi-phase system of FIG. 1 selectively configured in a cooling loop.

FIG. 4 is a diagrammatic illustration of an alternate embodiment of a multi-phase system.

FIG. 5 is a diagrammatic illustration of an electrical heating element coupled to the product container.

FIG. 6 is a diagrammatic illustration of a product heat exchanger coupled to a product container.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1, 2 and 3 are diagrammatic illustrations of one embodiment of a multi-phase heating and refrigeration system 10 (“multi-phase system”). The multi-phase system 10 is adapted to prepare (e.g., mix, pasteurize, cool, etc.) and store consumable products (e.g., dairy products, etc.) such as, but not limited to, milk shakes and soft serve ice cream. The multi-phase system 10 includes one or more product containers 12, 14, one or more product heat exchangers 16, one or more expansion valves 18, a liquid-to-air heat exchanger 20, a compressor 22, at least one system valve 24, and optionally a suction heat exchanger 26, and/or a product heater 31.

The product containers 12, 14 are adapted to hold, mix and/or dispense the consumable products. Each product container 12, 14 has an outer surface and an inner volume. The inner volume may be enclosed (e.g., where the product container is a sealed canister), or may be accessible (e.g., where the product container includes an access/fill aperture). For example, as illustrated in FIGS. 1 to 3, the product containers 12 are hoppers having fill apertures and the product containers 14 are sealed canisters. In some embodiments, one or more of the product containers 12, 14 includes a mixer (not shown) disposed within the inner volume.

The product heat exchangers 16 are adapted to transfer heat into or out of the product containers 12, 14. Each product heat exchanger 16 has a heat exchange surface and a refrigerant flow path 29 extending between first and second inlet/outlet apertures 28, 30 (“I/O apertures”). An inlet/outlet aperture is defined as an aperture that is operable as both a fluid inlet and a fluid outlet.

The expansion valves 18 (e.g., electrically actuated thermostatic expansion valves) are adapted to meter and expand refrigerant flowing therethrough. In some embodiments, the expansion valves 18 are bi-directional expansion valves operable to meter and expand the refrigerant flowing in both directions therethrough.

The liquid-to-air heat exchanger 20 (e.g., a tube and fin radiator) has a heat exchange surface and a refrigerant flow path extending between first and second I/O apertures 32, 34. The liquid-to-air heat exchanger 20 is adapted to transfer heat between refrigerant traveling through the refrigerant flow path and ambient air traveling over the heat exchange surface. In some embodiments, the liquid-to-air heat exchanger 20 is configured with at least one fan 36 to direct the ambient air over the heat exchange surface; i.e., induce convection.

The compressor 22 (e.g., a variable speed electrical compressor) has an inlet 38 and an outlet 40 and is adapted to compress refrigerant flowing therethrough. Compressors are known in the art, and the present invention is not limited to any particular configuration thereof.

The system valve 24 (e.g., an electrically actuated valve) is adapted to selectively configure the multi-phase system 10 between a plurality of heating/cooling loops. The heating/cooling loops, which include a first heating loop 42 (see FIG. 1) and a second heating loop 44 (see FIG. 2) and/or a cooling loop 46 (see FIG. 3), will be described below in further detail. In some embodiments, the system valve 24 includes a plurality of valves. For example, as illustrated in FIGS. 1 to 3, the system valve 24 includes a first three-way valve 48, a second three-way valve 50 and a four-way valve 52. The first and the second three-way valves 48, 50 each have a first I/O aperture 54, 56, a second I/O aperture 58, 60, and a third I/O aperture 62, 64. The four-way valve 52 has first, second, third and fourth I/O apertures 66, 68, 70, 72. However, the present invention is not limited to the number of valves or the types of valves in the aforesaid example. For example, in an alternate embodiment (see FIG. 4), the system valve 24 includes first, second and third two-way valves 73, 75, 77 (i.e., open or closed valves) and the four-way valve 52.

In those embodiments that include a suction heat exchanger 26, the suction heat exchanger 26 (e.g., a liquid-to-liquid heat exchanger) has a heat exchange surface disposed between first and second refrigerant flow paths 74, 76 and is adapted to transfer heat between the first and the second refrigerant flow paths 74, 76. Each of the first and the second refrigerant flow paths 74, 76 extend between two I/O apertures. An example of a suction heat exchanger (e.g., a “sub cooler”) is disclosed in U.S. Pat. No. 6,735,967 to Bischel et al., which is herein incorporated in by reference in its entirety.

The product heater 31 (e.g., see FIGS. 1-3 and 5) is adapted to transfer heat into the product containers 12, 14, and thus the consumable product disposed within the product containers 12, 14. In one embodiment, the product heater 31 includes one or more electrical heating elements 86 (see FIG. 5) such as, but not limited to, electrical resistance heaters.

Referring to FIG. 6, each product heat exchanger 16 is thermally coupled with a respective one of the product containers 12, 14; e.g., the heat exchange surface of one of the product heat exchangers 16 is connected to and wrapped around the outer surface of one of the product containers 12, 14. Referring to FIG. 5, where the multi-phase system 10 includes the electrical heating elements 86, each heating element 86 is thermally coupled with a respective one of the product containers 12, 14; e.g., one of the heating elements 86 is connected to and wrapped around the outer surface of one of the product containers 12, 14. However, the present invention is not limited to the configuration in the aforesaid examples. For example, in an alternate embodiment, one of the product heat exchangers 16 and/or one of the heating elements 86 can be disposed within the inner cavity of one of the product containers 12, 14.

FIG. 1 illustrates the multi-phase system 10 selectively configured in the first heating loop 42. Each product heat exchanger 16 is connected (i.e., fluidly coupled) to a respective one of the expansion valves 18. The expansion valves 18 are connected in parallel to the first refrigeration flow path 74 of the suction heat exchanger 26. The first refrigeration flow path 74 of the suction heat exchanger 26 is connected to the refrigerant flow path of the liquid-to-air heat exchanger 20 (e.g., the radiator). The refrigerant flow path of the liquid-to-air heat exchanger 20 is connected to the inlet 38 of the compressor 22 through the first and the second I/O apertures 54, 58 of the first three-way valve 48 and the first and the second I/O apertures 66, 68 of the four-way valve 52, respectively. The outlet 40 of the compressor 22 is connected in parallel to the product heat exchangers 16 through the third and the fourth I/O apertures 70, 72 of the four way valve and the first and the second I/O apertures 56, 60 of the second three-way valve 50, respectively.

Alternatively, as shown in FIG. 4, when the multi-phase system 10 is selectively configured in the first heating loop, the expansion valves 18 can be connected in parallel to the refrigerant flow path of the liquid-to-air heat exchanger 20 (e.g., the radiator) through the first two-way valve 73. In this embodiment, the liquid-to-air heat exchanger 20 is connected to the inlet 38 of the compressor 22 through the first and the second I/O apertures 66, 68 of the four-way valve 52. The outlet 40 of the compressor 22 is connected to the second refrigerant flow path 76 of the suction heat exchanger 26 through the third and the fourth I/O apertures 70, 72 of the four way valve. The second refrigerant flow path 76 of the suction heat exchanger 26 is connected in parallel to the product heat exchangers 16. In this configuration, the first two-way valve 73 is open and the second and the third two-way valves 75, 77 are closed.

FIG. 2 illustrates the multi-phase system 10 selectively configured in the second heating loop 44. The product heat exchangers 16 are connected in parallel to the inlet 38 of the compressor 22 through the second and the first I/O apertures 60, 56 of the second three-way valve 50 and the fourth and the second I/O apertures 72, 68 of the four-way valve 52, respectively. The outlet 40 of the compressor 22 is connected in parallel to the expansion valves 18 through the third and the first I/O apertures 70, 66 of the four-way valve 52 and the second and the third I/O apertures 58, 62 of the first three-way valve 48, respectively. Each expansion valve 18 is connected to a respective one of the product heat exchangers 16.

Alternatively, as shown in FIG. 4, when the multi-phase system 10 is selectively configured in the second heating loop, the product heat exchangers 16 can be connected in parallel the second refrigerant flow path 76 of the suction heat exchanger 26. In this embodiment, the second refrigerant flow path 76 of the suction heat exchanger 26 is connected to the inlet 38 of the compressor 22 through the fourth and the second I/O apertures 72, 68 of the four-way valve 52. The outlet 40 of the compressor 22 is connected in parallel to the expansion valves 18 through the third and the first I/O apertures 70, 66 of the four-way valve 52 and the second two-way valve 75, respectively. In this configuration, the second two-way valve 75 is open and the first and the third two-way valves 71, 77 are closed.

FIG. 3 illustrates the multi-phase system 10 selectively configured in the cooling loop 46. The product heat exchangers 16 are connected in parallel to the second refrigerant flow path 76 of the suction heat exchanger 26. The second refrigerant flow path 76 of the suction heat exchanger 26 is connected to the inlet 38 of the compressor 22 through the third and the first I/O apertures 64, 56 of the second three-way valve 50 and the fourth and the second I/O apertures 72, 68 of the four-way valve 52, respectively. The outlet 40 of the compressor 22 is connected to the refrigerant flow path of liquid-to-air heat exchanger 20 through the third and the first I/O apertures 70, 66 of the four-way valve 52 and the second and the first I/O apertures 58, 54 of the first three-way valve 48, respectively. The refrigerant flow path of the liquid-to-air heat exchanger 20 is connected to the first refrigerant flow path 74 of the suction heat exchanger 26. The first refrigerant flow path 74 of the suction heat exchanger 26 is connected in parallel to the expansion valves 18. Each expansion valve 18 is connected to a respective one of the product heat exchangers 16.

Alternatively, as shown in FIG. 4, when the multi-phase system 10 is selectively configured in the cooling loop, the product heat exchangers 16 can be connected in parallel the second refrigerant flow path 76 of the suction heat exchanger 26. In this embodiment, the second refrigerant flow path 76 of the suction heat exchanger 26 is connected to the inlet 38 of the compressor 22 through the fourth and the second I/O apertures 72, 68 of the four-way valve 52. The outlet 40 of the compressor 22 is connected to the refrigerant flow path of liquid-to-air heat exchanger 20 through the third and the first I/O apertures 70, 66 of the four-way valve 52. The refrigerant flow path of the liquid-to-air heat exchanger 20 is connected to the first refrigerant flow path 74 of the suction heat exchanger 26. The first refrigerant flow path 74 of the suction heat exchanger 26 is connected in parallel to the expansion valves 18 through the third two-way valve 77. In this configuration, the third two-way valve 77 is open and the first and the second two-way valves 73, 75 are closed.

The various embodiments of the multi-phase system 10 illustrated in FIGS. 1-3 and in FIG. 4 operate in a similar fashion to heat or cool the consumable products disposed in the product containers 12, 14. For example, the product heat exchangers 16 in both the embodiments in FIGS. 1, 2 and in FIG. 4 can transfer heat energy into the consumable product disposed in the product containers 12, 14 during a heating cycle. In another example, the liquid-to-air heat exchanger 20 in both the embodiments in FIG. 3 and in FIG. 4 can transfer heat energy into ambient air during a cooling cycle. Therefore, for simplicity, the operation of the multi-phase system 10 will be discussed below with reference to the embodiment illustrated in FIGS. 1-3. However, the following modes of operation can also be applied to the multi-phase system in FIG. 4.

In a first mode of operation, as illustrated in FIG. 1, the first three-way valve 48, the second three-way valve 50 and the four-way valve 52 in combination selectively configure the multi-phase system 10 into the first heating loop 42 (i.e., a heat pump) for heating the consumable products to a first temperature set point (e.g., approximately 120° F.). In the first heating loop 42, refrigerant (e.g., R-404A, etc.) travels from the product heat exchangers 16 to the expansion valves 18 where the refrigerant is expanded to a lower pressure. From the expansion valves 18, the refrigerant travels to the first refrigerant flow path 74 of the suction heat exchanger 26. Notably, there is substantially no temperature differential in the suction heat exchanger 26 since the second three-way valve 50 directs the relatively warmer refrigerant output from the compressor 22 to the product heat exchangers 12, 14 such that it bypasses the second refrigeration flow path 76 of the suction heat exchanger 26 (see below). Thus, in this mode the suction heat exchanger 26 is effectively non-operational since substantially no heat is available to be transferred into the refrigerant in the first refrigerant flow path 74. From the first refrigerant flow path 74 of the suction heat exchanger 26, the refrigerant travels to the liquid-to-air heat exchanger 20 (e.g., the radiator). Ambient air is directed through and/or around the liquid-to-air heat exchanger 20, e.g., via the fan 36. When the ambient air is warmer than the refrigerant traveling through the liquid-to-air heat exchanger 20, heat energy transfers from the ambient air to the refrigerant; i.e., the ambient air pre-heats the refrigerant. From the liquid-to-air heat exchanger 20, the first three-way valve 48 and the four-way valve 52 direct the pre-heated refrigerant to the compressor 22 to be compressed; i.e., transferring additional heat energy into the refrigerant. The four-way valve 52 and the second three-way valve 50 direct the heated and compressed refrigerant from the compressor 22 to the product heat exchangers 16, thus bypassing the second refrigerant flow path 76 of the suction heat exchanger 26. When the refrigerant in the product heat exchangers 16 is warmer than the consumable products in the product containers 12, 14, the heat energy from the refrigerant transfers to the consumable products through the product containers 12, 14; i.e., the refrigerant heats the consumable products.

As set forth above, the refrigerant is heated in the liquid-to-air heat exchanger 20 and the compressor 22. Notably, in the liquid-to-air heat exchanger 20, minimal electrical energy is used to facilitate the heating of the refrigerant via the fan 36; i.e., the heat energy transferred into the refrigerant is greater than the electrical energy used to power the fan 36. Heat energy transferred from the ambient air into the refrigerant increases the efficiency of the process by decreasing the amount of work energy that would otherwise be used to increase the temperature of the products in the product containers 12, 14. For example, where (i) the ambient air has a temperature of approximately 70° F., (ii) the refrigerant in a low side of the first heating loop 42 (i.e., between the second I/O aperture of the expansion valves 18 and the inlet 38 of the compressor 22) has a temperature of approximately 50° F. and a pressure of approximately 118 pounds per square inch absolute (“psia”), and (iii) the refrigerant in a high side of the first heating loop 42 (i.e., between the outlet 40 of the compressor 22 and the second I/O aperture of the product containers 12, 14) has a temperature of approximately 100° F. and a pressure of approximately 250 psia, the efficiency of the multi-phase system 10 can exceed one (e.g., ˜5.0 efficiency where enthalpy for heating equals approximately 61.65 BTU/lb and electrical enthalpy input into the system is approximately 12.39 BTU/lb).

In a second mode of operation, as illustrated in FIG. 2, the first three-way valve 48, the second three-way valve 50 and the four-way valve 52 in combination selectively configure the multi-phase system 10 into the second heating loop 44 for heating the consumable products to a second temperature set point (e.g., above approximately 150° F.). In the second heating loop 44, the second three-way valve 50 and the four-way valve 52 direct the refrigerant from the product heat exchangers 16 to the compressor 22 to be compressed; i.e., transferring heat energy into the refrigerant. The four-way valve 52 and the first three-way valve 48 direct the heated refrigerant from the compressor 22 to the expansion valves 18 where the refrigerant expands to a lower pressure. From the expansion valves 18, the heated refrigerant travels to the product heat exchangers 16. When the refrigerant in the product heat exchangers 16 is warmer than the consumable products in the product containers 12, 14, heat energy transfers from the refrigerant to the consumable products; i.e., the refrigerant heats the consumable products.

In a third mode of operation, when the multi-phase system 10 includes the electrical heating elements 86, the heating elements 86 can be used to transfer heat energy to the consumable products through the product containers 12, 14.

In a fourth mode of operation, as illustrated in FIG. 3, the first three-way valve 48, the second three-way valve 50 and the four-way valve 52 in combination selectively configure the multi-phase system 10 into the cooling loop 46 for cooling the consumable products to a third temperature set point (e.g., 41° F.). In the cooling loop 46, refrigerant travels to the second refrigerant flow path 76 of the suction heat exchanger 26. Heat energy transfers from the suction heat exchanger 26 into the refrigerant; i.e., the suction heat exchanger 26 heats the refrigerant travelling through the second refrigerant flow path 76 thereof. The second three-way valve 50 and the four-way valve 52 direct the refrigerant from the second refrigerant flow path 76 to the compressor 22 to be compressed. The four-way valve 52 and the first three-way valve 48 direct the compressed refrigerant from the compressor 22 to the liquid-to-air heat exchanger 20. Ambient air is directed through and/or around the liquid-to-air heat exchanger 20, e.g., via the fan 36. When the refrigerant traveling through the liquid-to-air heat exchanger 20 is warmer than the ambient air, heat energy transfers from the refrigerant to the ambient air; i.e., the ambient air cools the refrigerant. The refrigerant travels from the liquid-to-air heat exchanger 20 to the first refrigerant flow path 74 of the suction heat exchanger 26. Heat energy transfers from the refrigerant to the suction heat exchanger 26; i.e., the suction heat exchanger 26 cools the refrigerant travelling through the first refrigerant flow path 74 thereof. The refrigerant travels from the first refrigerant flow path 74 of the suction heat exchanger 26 to the expansion valves 18, where the refrigerant expands further cooling the refrigerant. The cooled refrigerant travels from the expansion valves 18 to the product heat exchangers 16. When the consumable products in the product containers 12, 14 are warmer than the refrigerant in the product heat exchangers 16, heat transfers from the consumable products to the refrigerant, thereby cooling the consumable products.

During a heating and cooling cycle, the multi-phase system 10 can operate in a multiple modes of operation. For example, during pasteurization, the multi-phase system 10 can heat the consumable products to the first temperature using the first mode of operation. To heat the consumable products to the second temperature, the multi-phase system 10 can operate according to the second and/or the third modes of operation. During cooling (e.g., chilling or freezing the dairy product to form an ice cream product, etc.), the multi-phase system 10 can chill or freeze the consumable products using the fourth mode of operation.

While various embodiments of the present invention have been disclosed, it will be apparent to those of ordinary skill in the art that many more embodiments and implementations are possible within the scope of the invention. Accordingly, the present invention is not to be restricted except in light of the attached claims and their equivalents.

Claims

1. A multi-phase heating system, comprising:

a product container;

a product heat exchanger that selectively transfers heat into or out of the product container;

a liquid-to-air heat exchanger;

a compressor; and

a system valve that selectively configures the system between a first heating loop and a second heating loop, which first heating loop extends through the product heat exchanger, the liquid-to-air heat exchanger and the compressor, and which second heating loop extends through the product heat exchanger and the compressor, and bypasses the liquid-to-air heat exchanger.

2. The system of claim 1, wherein the system valve further selectively configures the system into a cooling loop that extends through the liquid-to-air heat exchanger, the product heat exchanger, and the compressor.

3. The system of claim 2, further comprising a bi-directional expansion valve coupled with the product heat exchanger.

4. The system of claim 2, wherein the system valve comprises a four-way valve, a first three-way valve, and a second three-way valve, which four-way valve couples the first and the second three-way valves to the compressor.

5. The system of claim 2, wherein the system valve comprises a four-way valve, a first two-way valve, a second two-way valve and a third two-way valve, which four-way valve couples the first, the second and the third two-way valves to the compressor.

6. The system of claim 2, further comprising a suction heat exchanger coupled between the product heat exchanger and the liquid-to-air heat exchanger, and between the product heat exchanger and the compressor in the cooling loop.

7. The system of claim 1, wherein the product container comprises at least one of a product storage canister and a hopper.

8. The system of claim 1, further comprising a product heater disposed with the product container.

9. A heating and refrigeration system, comprising:

a product container;

a product heat exchanger that selectively transfers heat into or out of the product container;

an expansion valve;

a liquid-to-air heat exchanger;

a compressor; and

a system valve that selectively configures the system between a cooling loop and heating loop, which cooling loop extends through the liquid-to-air heat exchanger, the expansion valve, the product heat exchanger and the compressor, and which heating loop extends through the product heat exchanger, the expansion valve, the liquid-to-air heat exchanger and the compressor.

10. The system of claim 8, wherein the expansion valve comprises a bi-directional expansion valve.

11. The system in claim 9, wherein the system valve further configures the system into a second heating loop that extends through the product heat exchanger, the expansion valve and the compressor, and bypasses the liquid-to-air heat exchanger.

12. The system of claim 9, further comprising a product heater disposed with the product container, which product heater transfers heat into the product container.

13. The system of claim 9, wherein the system valve comprises a four-way valve, a first three-way valve, and a second three-way valve, which four-way valve couples the compressor to the first and the second three-way valves.

14. A method for heating and cooling a consumable product disposed in a product container, comprising:

heating the consumable product to a first temperature by transferring heat from ambient air to refrigerant through a liquid-to-air heat exchanger; and

heating the consumable product to a second temperature without transferring heat from the ambient air to the refrigerant through the liquid-to-air heat exchanger;

wherein the second temperature is greater than the first temperature.

15. The method of claim 14, wherein the consumable product is a diary product.

16. The method of claim 14, wherein the step of heating the consumable product to the second temperature comprises the step of heating the consumable product via a product heater.

17. The method of claim 16, wherein the product heater is an electrical heating element.

18. The method of claim 14, wherein the step of heating the consumable product to the second temperature comprises the step of compressing the refrigerant in a compressor.

19. The method of claim 14, further comprising the step of cooling the consumable product.

20. The method of claim 14, further comprising the steps of:

configuring a multi-phase system into a first heating loop for heating the consumable product to the first temperature, which multi-phase system includes the liquid-to-air heat exchanger; and

configuring the multi-phase system into a second heating loop for heating the consumable product to the second temperature, which second heating loop bypasses the liquid-to-air heat exchanger.