US20160003500A1

US20160003500A1 - Evaporator and methods of using same

Info

Publication number: US20160003500A1
Application number: US14/790,732
Authority: US
Inventors: Gesueldo Ricotta
Original assignee: Individual
Current assignee: Individual
Priority date: 2014-07-02
Filing date: 2015-07-02
Publication date: 2016-01-07
Also published as: WO2016004349A1

Abstract

An evaporator and methods of using the same are described herein. A vapor-compression refrigeration apparatus in accordance with an embodiment of the present technology utilizes a fluid refrigerant and can include a compressor, a condenser, an expansion device and an evaporator arranged in succession and in fluid communication within a closed loop in order to circulate the fluid refrigerant. The apparatus can include at least one line within the closed loop in operable communication with the condenser for reducing temperature of at least a portion of the fluid refrigerant coming from the condenser prior to the fluid refrigerant entering the expansion device.

Description

CROSS-REFERENCE TO RELATED APPLICATION(S)

The present application claims priority to and the benefit of U.S. Provisional Application No. 62/020,274, filed Jul. 2, 2014 and titled EVAPORATOR AND METHODS OF USING SAME, which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

The present application relates generally to vapor-compression refrigeration systems and methods and, in particular, an improved evaporator.

BACKGROUND OF THE INVENTION

A conventional vapor-compression refrigeration system typically includes a compressor, a condenser, an expansion device and an evaporator interconnected to form a closed loop system through which refrigerant continuously circulates. The main steps of a vapor-compression system are compression of the refrigerant by the compressor, heat rejection of the refrigerant in the condenser, metering of the refrigerant by the expansion device and absorption of heat by the refrigerant in the evaporator. Such vapor-compression systems are commonly used in air conditioning systems found in buildings, vehicles, and domestic and commercial refrigerators, among others.

SUMMARY OF THE INVENTION

The present invention provides vapor-compression refrigeration systems and methods for improving the efficiency of such systems. In particular, provided herein are vapor-compression refrigeration apparatus utilizing a fluid refrigerant and comprising a compressor, a condenser, an expansion device and an evaporator arranged in succession and in fluid communication within a closed loop in order to circulate the fluid refrigerant. In one embodiment, the apparatus comprises at least one line within the closed loop that is in operable communication with the condenser for reducing temperature of at least a portion of the fluid refrigerant prior to the fluid refrigerant entering the expansion device.
In some embodiments, the at least one line within the closed loop that is in operable communication with the condenser traverses at least a portion of the evaporator prior to operable communication with the expansion device.
In some embodiments, the apparatus further comprise a cooling device within the closed loop, interposed between the condenser and the expansion device, wherein the cooling device is operably linked to the at least one line disposed in operable communication with the condenser for reducing temperature of at least a portion of the fluid refrigerant prior to the fluid refrigerant entering the expansion device.
The present invention also provides methods of increasing the efficiency of a vapor-compression refrigeration apparatus, the method comprising at least the step of reducing temperature of at least a portion of the fluid refrigerant prior to the fluid refrigerant entering the expansion device.
In some embodiments, the method comprises the step of reducing temperature of at least a portion of the fluid refrigerant prior to the fluid refrigerant entering the expansion device by traversing at least a portion of the fluid refrigerant through at least a portion of the evaporator prior to the refrigerant entering the expansion device.
In other embodiments, the method provides reducing temperature of at least a portion of the fluid refrigerant prior to the fluid refrigerant entering the expansion device by traversing at least a portion of the fluid refrigerant through a cooling device.
The present invention also provides an evaporator comprising a plurality of coils, wherein at least one of the plurality of coils is configured within the evaporator so that fluid refrigerant traverses at least a portion of the evaporator in a direction substantially opposite the flow direction of the refrigerant through the remaining plurality of coils.
In one embodiment, the invention provides an evaporator comprising a plurality of coils housed inside a radiator frame and a sub-cooling coil external to and in contact with the radiator frame, wherein the subcooling coil is configured to receive refrigerant from a condenser and to deliver refrigerant to an expansion device. In another embodiment, the present invention provides an evaporator comprising a plurality of coils, wherein at least one of the plurality of coils is configured proximate to the evaporator so fluid refrigerant from the condenser traverses proximate to at least a portion of the evaporator prior to the fluid refrigerant.

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the present disclosure can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale. Instead, emphasis is placed on illustrating clearly the principles of the present disclosure.

FIG. 1 is a block diagram of a conventional vapor-compression refrigeration system comprising an evaporator 100, a compressor 200, a condenser 300 and an expansion device 400.

FIG. 2 is depiction of a cross section of a conventional A coil evaporator 201 comprising two vertical risers 203, each vertical riser 203 comprising a plurality of coils 202 (e.g. coil 202 a,

coil

202 b and coil 202 c).

FIG. 3 is a depiction of a cross section of a conventional A coil evaporator 201 and coil inlets 103 which connect the expansion device 400, via the capillary tubes 210, to the plurality of coils 202 to and further including a coil outlets 104, which connect the plurality of coils to the compressor 200.

FIG. 4 is a depiction of a cross section of a modified A coil evaporator 401. The condenser 300 is connected by the condenser inlet line 405 to at least one of the plurality of coils 202, for example coil 202 b, via coil inlet 103 b. The expansion device 400 is directly linked to coil 202 b via the coil outlet 104 b and by expansion inlet line 115.

FIG. 5 is a depiction of a vapor-compression refrigeration system comprising of a cooling device 501 in operable communication with a condenser 300 and an expansion device 400.

FIG. 6 is a depiction of a cross section of a modified A coil evaporator 401 comprising an additional coil 202 d which connects the condenser 300 to the expansion device 400 via an expansion inlet line 115. Coil 202 d is located proximate to the frame 601 of the modified A coil evaporator 401 and can be in contact with the exterior surface of the radiator frame or in close proximity to it.

FIG. 7 is a depiction of a cross section of a modified A coil evaporator 401 comprising an additional coil 202 d which connects the condenser 300 to the expansion device 400 via an expansion inlet line 115. Coil 202 d is located within the frame 601 of the modified A coil evaporator 401.

FIG. 8 is a depiction of a cross section of a modified evaporator 801 comprising an additional coil 202 d which connects the condenser 300 to the expansion device 400 via an expansion inlet line 115. Coil 202 d is located within the frame 601 of the modified evaporator 801.

FIG. 9 is a depiction of a cross section of a modified evaporator 801 comprising an additional coil 202 d which connects the condenser 300 to the expansion device 400 via an expansion inlet line 115. Coil 202 d is located proximate to the frame 601 of the modified evaporator 801.

FIG. 10 is a block diagram of a vapor-compression refrigeration system comprising a modified evaporator 401, a compressor 200, a condenser 300 and an expansion device 400, having the condenser 300 connected by the condenser inlet line 405, which passes through the modified evaporator 401, and expansion inlet line 115 to the expansion device 400 and having the condenser 300 directly connected to the expansion device 400.

FIG. 11 is a block diagram of a vapor-compression refrigeration system comprising a modified evaporator 401, a compressor 200, a condenser 300 and an expansion device 400 having the condenser 300 connected by the condenser inlet line 405 and expansion inlet line 115 to the expansion device 400.

FIG. 12 is a block diagram of a vapor-compression refrigeration system comprising an evaporator 100, a compressor 200, a condenser 300 and an expansion device 400 having the condenser 300 connected to a cooling device 501 and to the expansion device 400.

FIG. 13 is another block diagram of a vapor-compression refrigeration system comprising an evaporator 100, a compressor 200, a condenser 300 and an expansion device 400 with the condenser 300 connected to a cooling device 501.

FIG. 14 is a depiction of a cross section of a modified A coil evaporator 401. The condenser 300 is connected by the condenser inlet line 405 to at least one of the plurality of coils 202, for example coil 202 b, via coil inlet 103 b. The expansion device 400 is directly linked to coil 202 b via the coil outlet 104 b and by expansion inlet line 115.

FIG. 15 is a depiction of a cross section of another vapor-compression refrigeration system comprising a cooling device 501 in operable communication with a condenser 300 and an expansion device 400.

FIG. 16 is a depiction of yet another vapor-compression refrigeration system comprising a cooling device 1601 in operable communication with a condenser 300, an expansion device 400, compressor 200, and an evaporator.

DETAILED DESCRIPTION

Apparatus and methods are provided herein that improve the efficiency of conventional vapor-compression refrigeration systems.
This description will enable one skilled in the art to make and use the invention, and describes several embodiments, adaptations, variations, alternatives and uses of the invention. These and other embodiments, features and advantages of the present invention will become more apparent to those skilled in the art when taken with reference to the following detailed description of the invention and in conjunction with the accompanying drawings.
As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless the context clearly indicates otherwise. Unless defined otherwise, all technical terms used herein have the same meaning as is commonly understood by one of ordinary skill in the art to which this invention belongs.
The term “comprising,” which is synonymous with “including,” “containing,” or “characterized by” is inclusive or open-ended and does not exclude additional, unrecited elements or method steps. “Comprising” is a term of art used in claim language which means that the named claim elements are essential, but other claim elements may be added and still form a construct within the scope of the claim.
As used herein, and unless otherwise specifically stated, the terms “operable communication,” “operably connected,” and the like, mean that the particular elements communicate or are connected in such a way that they cooperate to achieve their intended function or functions. The “connection” may be direct, or indirect or remote.
Referring now generally to FIG. 1, a flow diagram of a conventional vapor-compression system is illustrated. The four major components of a conventional vapor-compression refrigeration system include: an evaporator 100, a compressor 200, a condenser 300 and an expansion device 400. Arrows connecting the component parts indicate the typical flow of fluid refrigerant within the system. In a typical system, refrigerant enters an evaporator 100 in the form of a cool, low pressure mixture of liquid and vapor. Heat is transferred to the refrigerant from the relatively warm air that is being cooled, causing the liquid refrigerant to boil. The resulting refrigerant vapor is then pumped from the evaporator 100 by the compressor 200, which increases the pressure and temperature of the vapor. The resulting hot, high pressure refrigerant vapor enters the condenser 300 where heat is transferred to ambient air, which is at a lower temperature than the refrigerant. Inside the condenser 300, the refrigerant vapor condenses into a warm liquid. This warm liquid refrigerant then flows from the condenser 300 to the expansion device 400.
The expansion device 400 removes pressure from the liquid refrigerant to allow expansion or change of state from a liquid to a vapor in the evaporator 100. The high-pressure liquid refrigerant entering the expansion device 400 is warm, which may be verified by feeling the liquid line at its connection to the expansion device 400. The liquid refrigerant leaving the expansion device 400 is cold. The orifice within the valve does not remove heat, but only reduces pressure. Heat molecules contained in the liquid refrigerant are thus allowed to spread as the refrigerant moves out of the orifice. Under a greatly reduced pressure the liquid refrigerant is at its coldest as it leaves the expansion device 400 and enters the evaporator 100. Pressures at the inlet and outlet of the expansion device 400 will closely approximate gauge pressures at the inlet and outlet of the compressor in most systems. The similarity of pressures is caused by the closeness of the components to each other. The slight variation in pressure readings of a very few pounds is due to resistance, causing a pressure drop in the lines and coils of the evaporator 100 and condenser 200. The expansion device 400 creates a pressure drop that reduces the pressure of the refrigerant to that of the evaporator 100. At this low pressure, a small portion of the refrigerant boils (or flashes), cooling the remaining liquid refrigerant to the desired evaporator temperature. The cool mixture of liquid and vapor refrigerant enters the evaporator 100 to repeat the cycle.
The efficiency of the vapor-compression system depends, at least in part, on the heat absorption from the evaporator 100 and the efficiency of the compressor 200. An evaporator 100 typically comprises at least one long coil tube, more typically a plurality of coiled tubes, through which the fluid refrigerant flows and absorbs heat from a volume of ambient air that is desired to be cooled. An example of an evaporator 100 is an A coil evaporator 201 illustrated in FIG. 2 comprising two vertical risers 203 with each vertical riser comprising a plurality of coils 202 (e.g. coil 202 a, coil 202 b and coil 202 c). Referring to FIG. 3, in one embodiment, each of the plurality of coils 202 (e.g. coil 202 a, coil 202 b and coil 202 c) has a coil inlet 103 and a corresponding coil outlet 104. In a conventional vapor-compression system the expansion device 400 is connected via capillary tubes 210 to the plurality of coils 202 by coil inlets 103. In order to absorb heat from a volume of ambient air, the temperature of the refrigerant must be lower than that of ambient air when it enters the evaporator 100. In one embodiment, the present invention provides for a modified system and method of using such modified system which lowers the temperature of the refrigerant prior to entry of the refrigerant into the evaporator as compared to conventional vapor-compression refrigeration systems.

System

In one embodiment, the invention provides an improved vapor-compression refrigeration apparatus wherein at least one tube (e.g., the condenser inlet line 405) within the closed loop is in operable communication with the condenser and converts at least a portion of the fluid refrigerant to a lower temperature prior to the fluid refrigerant entering the expansion device 400. Referring to FIG. 4, in one embodiment, the invention provides a modified evaporator 401. In one embodiment, the condenser 300 is in direct communication with at least one of the plurality of coils 202, for example coil 202 b via coil inlet 103 b, for receiving warm liquid refrigerant directly (i.e. without passing through the expansion device 400) from the condenser 300. In certain embodiments, the condenser inlet line 405 connects the condenser 300 in direct communication with at least one of the plurality of coils 202. In one embodiment, the expansion device 400 is in direct communication with at least one of the plurality of coils 202, for example coil 202 b via corresponding coil outlet 104 b, for receiving liquid refrigerant after it has passed through the modified evaporator 401. One of skill in the art would appreciate that any and/or one or more, of the plurality of coils 202 could be directly linked to the condenser 300 and/or expansion device 400. One of skill in the art would also appreciate that the refrigerant could traverse proximate to (e.g., not directly through, adjacent, nearby, etc.) an evaporator 100. In some embodiments, one or more additional coils 202 d may be positioned proximate to or within the frame 601 of the evaporator 100, for example a modified evaporator 801 or modified A coil evaporator 401 (See, e.g., FIGS. 6-9). For example, liquid refrigerant from condenser 300 can enter a coil 202 d through an inlet 103 d proximate to or within the frame of the modified evaporator 801 or modified A coil evaporator 401 without first passing through the expansion device 400. The expansion device 400 is in direct communication with coil 202 d via corresponding coil outlet 104 d, for receiving liquid refrigerant after it has passed through the modified evaporator 801 or modified A coil evaporator 401. In some embodiments, the liquid refrigerant exits coil 202 b or 202 d via the corresponding coil outlets 104 b or 104 d and is directly linked to the expansion device 400 by expansion inlet line 115. In another embodiment, the remaining plurality of coils 202, for example coil 202 a and coil 202 c, are in operative communication with the expansion device 400, via corresponding coil inlets 103, for receiving cold low pressure refrigerant that has passed through the coils 202 b or 202 d as described above and been received by the expansion device 400. In one embodiment, expansion device 400 is in operative communication with a plurality of coil inlets 103, for example by connection with capillary tubes 210 as described above. In one embodiment, the capillary tubes 210 are copper tubes of small internal diameter, for example from about 0.5 to 2.28 mm (0.020 to 0.09 inches).
Referring to FIG. 4, in one embodiment, the condenser inlet line 405 is positioned substantially at the top of the modified evaporator 401. In one embodiment, at least one of a plurality of coils 202 (e.g., coil 202 b) is in operative communication with coil inlet 103 b and corresponding coil outlet 104 b that is in operative communication with the expansion device 400, for example by the expansion inlet line 115. In one embodiment, coil outlet 104 b is positioned substantially at the bottom of the modified evaporator 401. In one embodiment, the remaining plurality of the coils 202 are in operative communication with the expansion device 400 via the capillary tubes 210.that are operably connected to the remaining inlets 103 positioned at the bottom of the evaporation with corresponding outlets 104 positioned at the top of the evaporator. Therefore, in some embodiments the fluid refrigerant may flow through one or more coils (e.g., coil 202 b) in the direction opposite (e.g., transverse, cross-wise) that of the remaining plurality of coils 202 (e.g, coil 202 a and coil 202 c). For example, the fluid refrigerant can flow downward through coil 202 b but upward through coils 202 a and 202 c. In other embodiments, the opposite orientation can be achieved. In yet further embodiments, the refrigerant can flow in the substantially same direction or orientation (e.g., parallel) through all the coils.
Referring to FIG. 5, in yet another embodiment the apparatus further comprises a cooling device 501 (e.g., heat exchanger, water condenser, etc.) within the closed loop and interposed between the condenser 300 and the expansion device 400. Referring to FIGS. 12-13, the cooling device 501 may be operably linked to a condenser inlet line 405 which connects the condenser 300 to the cooling device 501. In another embodiment, an expansion inlet line 115 connects the cooling device 501 with the expansion device 400. In some embodiments the cooling device 501 is a separate, self-containing vapor-compression refrigeration system, a fan, heat exchanger, water condenser, or the like. Referring to FIGS. 10-11, in other embodiments, the inlet lines 405 and/or 115 can be used without the cooling device 501.
FIG. 14 illustrates a modified evaporator 401 similar to the embodiment of FIG. 4 but with one or more different features. For example, the modified evaporator 401 includes a line 1412 connecting two or more coils 202 b and 202 a (e.g., such that refrigerant from condenser inlet line 405 traverses two or more coils before being received by the expansion device 400). The condenser 300 is operably connected by the condenser inlet line 405 to at least one of the plurality of coils 202, for example coil 202 b, via coil inlet 103 b. Refrigerant or other fluid flows through from the condenser 300 through the evaporation 401 without first passing through the expansion device 400. Refrigerant flows through coil 202 b from inlet 103 b to outlet 104 b where it flows into the inlet 103 a of coil 202 a via the line 1412. The refrigerant or other fluid continues to flow through the second coil 202 a to the outlet 104 a and then to the expansion device 400. The expansion device 400 is directly linked to coil 202 a via the coil outlet 104 a and expansion inlet line 115. Flowing the refrigerant or other fluid through two or more coils can increase cooling relative to flow through one coil. The other outlets 104 can be connected to the compressor 200 such that fluid flows upward or downward from the other inlets 103 of the other coils 202 to the outlets 104 as described above. The other corresponding inlets 103 can be connected to the expansion device 400 as in a conventional system such that the cooled refrigerant is provided to the evaporator accordingly. In other embodiments, three, four, or more coils can be linked such that the refrigerant can flow through even more coils before reaching the expansion device 400.
FIG. 15 is a depiction of a cross section of another vapor-compression refrigeration system comprising a cooling device 501 in operable communication with a condenser 300 and an expansion device 400 (e.g., metering or other distribution device). The cooling device 501 (e.g., heat exchanger, water condenser, etc.) is coupled within the closed loop and interposed between the condenser 300 and the expansion device 400. The cooling device 501 may be operably linked to a condenser inlet line 405 which connects the condenser 300 to the cooling device 501. One or more expansion inlet and outlet lines 115, 116 connect the cooling device 501 with the expansion device 400 to cool the cooling device 501 and/or fluid flowing therethrough and to provide the cooled fluid (e.g., refrigerant) to the expansion device 400 with direction of flow indicated by the broken arrows. The expansion device 400 can then provide pre-cooled or sub-cooled fluid to the evaporator through the inlets 103 of the coils 202 where the fluid flows through the coils 202 and out the outlets 104 to the compressor 200. In some embodiments the cooling device 501 is a separate, self-containing vapor-compression refrigeration system, a fan, heat exchanger, water condenser, or the like.
FIG. 16 is a depiction of another vapor-compression refrigeration system comprising a cooling device 1601 (e.g., water condenser, heat exchanger, etc.) in operable communication with a compressor 200 and an evaporator. One or more coils 202 via their corresponding outlets 104 are connected to an inlet of the cooling device 1601 to cool the cooling device 1601 and/or fluid (e.g., refrigerant) flowing therethrough to the compressor 200. The fluid flowing therethrough can flow from the condenser 300 through the cooling device 1601 to be cooled before entering the expansion device 400 or other metering or distribution device which can provide the refrigerant to the evaporator through inlets 103. The remaining coils 202 and their corresponding outlets 104 can be connected to the compressor 200 for receiving the refrigerant and fluid can flow therethrough to circulate in a conventional manner without passing through the cooling device 1601.

Methods

In traditional operation, the flash gas produced in the evaporator 100 creates inefficiency in a vapor-compression refrigeration system. In one embodiment, the invention provides a method of reducing flash gas and improving efficiency by pre-cooling warm refrigerant coming from the condenser 300 prior to the refrigerant entering the expansion device 400.
In one embodiment, the method of increasing the efficiency of a vapor-compression refrigeration apparatus comprises at least the step of reducing temperature of at least a portion of the fluid refrigerant prior to the fluid refrigerant entering the expansion device 400. In some embodiments, the temperature of the fluid refrigerant entering the expansion device of the present invention is reduced by about 5%, about 10%, about 20%, about 30%, about 40%, about 50%, or about 60% as compared to the temperature the fluid refrigerant that enters the expansion device in a traditional vapor-compression refrigeration apparatus. In other embodiments, the method of increasing the efficiency of a vapor-compression refrigeration apparatus further comprises reducing the pressure of at least a portion of the fluid refrigerant prior to the fluid refrigerant entering the expansion device.
One of skill in the art would also appreciate that the refrigerant can traverse proximate to (e.g., not directly through) an evaporator 100 prior to the fluid refrigerant entering the expansion device 400.
In one embodiment, the method involves reducing the temperature of at least a portion of the fluid refrigerant prior to the fluid refrigerant entering the expansion device 400 by traversing at least a portion of the fluid refrigerant through at least a portion of the modified evaporator 401 prior to entering the expansion device 400.
In yet another embodiment, the method involves reducing the temperature of at least a portion of the fluid refrigerant prior to the fluid refrigerant entering the expansion device 400 by traversing at least a portion of the fluid refrigerant through a cooling device 501, 1601. In some embodiments the cooling device 501, 1601 is a separate, self-containing vapor-compression refrigeration system, a fan, heat exchanger, water condenser, or the like.

Evaporator

The present invention also provides an evaporator 100, more particularly a modified evaporator 401, comprising a plurality of coils 202, wherein at least one of the plurality of coils, for example coil 202 b, is configured within the modified evaporator 401 so that fluid refrigerant traverses at least a portion of the modified evaporator 401 in a direction substantially opposite the flow direction of the refrigerant through the remaining plurality of coils 202, for example coil 202 a and coil 202 c.
In one embodiment, at least one of the plurality of coils 202, for example coil 202 b, of the modified evaporator 401 is in direct communication with a condenser 300 via a coil inlet, for example coil inlet 103 b, for receiving warm liquid refrigerant directly (i.e. without passing through an expansion device 400) from the condenser 300. In one embodiment, the at least one of the plurality of coils 202, for example coil 202 b, of the modified evaporator 401 is in direct communication with the expansion device 400 via coil outlet 104 b. The at least one of the plurality of coils 202, for example coil 202 b, of the modified evaporator 401 may be directly linked to the expansion device 400 by expansion inlet line 115.
Where methods and steps described above indicate certain events occurring in a certain order, those of ordinary skill in the art will recognize that the ordering of certain steps may be modified and that such modifications are in accordance with the variations of the invention. Additionally, while the steps of the present invention are typically performed continuously and concurrently in a parallel process, the steps may also be performed sequentially.
The particular embodiments of the subject matter here presented is by way of illustration only, and is, in no way meant to be restrictive. Numerous changes and modifications may be made to the invention. Therefore, to the extent there are variations of the invention, which are within the spirit of the disclosure or equivalent to the inventions found in the appended claims, it is the intent that this patent cover those variations as well. For example, any of the features in whole or in part of any of the embodiments can be combined with any of the other embodiments.

Claims

I/We claim:

1. A vapor-compression refrigeration apparatus utilizing a fluid refrigerant and comprising a compressor, a condenser, an expansion device and an evaporator arranged in succession and in fluid communication within a closed loop in order to circulate the fluid refrigerant, the apparatus comprising: at least one line within the closed loop in operable communication with the condenser for reducing temperature of at least a portion of the fluid refrigerant coming from the condenser prior to the fluid refrigerant entering the expansion device.

2. The apparatus of claim 1 wherein the at least one line within the closed loop in operable communication with the condenser traverses at least a portion of the evaporator prior to operable communication with the expansion device.

3. The apparatus of claim 1 further comprising a cooling device within the closed loop, interposed between the condenser and the expansion device, wherein the cooling device is operably linked to the at least one line disposed in operable communication with the condenser for reducing the temperature of at least a portion of the fluid refrigerant prior to the fluid refrigerant entering the expansion device.

4. A method of increasing the efficiency of a vapor-compression refrigeration apparatus, the method comprising at least the step of: reducing temperature of at least a portion of fluid refrigerant exiting a condenser to a lower temperature prior to the fluid refrigerant entering the expansion device.

5. The method of claim 4, further comprising reducing the temperature of at least a portion the fluid refrigerant prior to the fluid refrigerant entering the expansion device by traversing at least a portion of the fluid refrigerant through at least a portion of the evaporator prior to entering the expansion device.

6. The method of claim 4, further comprising reducing the temperature of at least a portion of the fluid refrigerant prior to the fluid refrigerant entering the expansion device by traversing at least a portion of the fluid refrigerant through a cooling device.

7. An evaporator comprising a plurality of coils wherein at least one of the plurality of coils comprises an inlet for receiving warm liquid refrigerant directly from a condenser.

8. The evaporator of claim 7 wherein at least one of the plurality of coils comprises a coil outlet that is capable of direct operable communication with an expansion device.

9. The evaporator of claim 7 wherein the at least one of the plurality of coils is configured to be directly linked to an expansion device via an expansion inlet line.

10. An evaporator comprising a plurality of coils, wherein at least one of the plurality of coils is configured within the evaporator so fluid refrigerant traverses at least a portion of the evaporator in a direction substantially opposite the flow direction of the refrigerant through the remaining plurality of coils.

11. An evaporator comprising a plurality of coils, wherein at least one of the plurality of coils is configured within the evaporator so fluid refrigerant traverses at least a portion of the evaporator in a direction substantially opposite of refrigerant flowing through a remaining plurality of coils.

12. An evaporator comprising a plurality of coils housed inside a radiator frame and a sub-cooling coil that is external to and in close proximity or contact with the radiator frame, wherein the sub-cooling coil is configured to receive refrigerant from a condenser and to deliver refrigerant to an expansion device.