Condenser subassembly with integrated flash tank

Abstract

The present invention relates to a condenser subassembly with an integrated flash tank. Specifically, a condenser subassembly for providing an economizer function in a refrigeration circuit, the condenser subassembly comprising: a condenser chamber 113; a flash tank chamber 114; an expansion device 117; and a shell, wherein the shell defines a container 112a, the container comprising the condenser chamber 113 and the flash tank chamber 114, wherein the condenser chamber 113 and the flash tank chamber 114 are separated from each other by a partition 115a in the container 112a, and wherein the expansion device 117 is arranged to transfer condensed refrigerant from the condenser chamber 113 to the flash tank chamber 114.

Description

Technical Field

[0001] The present invention relates to a condenser subassembly for providing an economizer function in a refrigeration circuit, a refrigeration circuit comprising such a condenser assembly and a method of manufacturing such a condenser subassembly. Background Art

[0002] A refrigeration circuit consists of a compressor, condenser (i.e., heat rejection heat exchanger), expansion device, and evaporator (i.e., heat absorption heat exchanger), and is used to cool or heat an environment or substance. Economizer cycles are sometimes used to increase the efficiency and capacity of the system.

[0003] One form of the economizer cycle utilizes a flash tank and operates by expanding the refrigerant leaving the condenser to an intermediate pressure in the flash tank (lower than the refrigerant pressure in the condenser, but higher than the pressure in the evaporator) and separating the expanded refrigerant stream.

[0004] The vapor refrigerant is directed to the economizer port of the compressor and the liquid refrigerant is directed to the evaporator via the second main expansion valve. The main benefit of this separation of vapor and liquid refrigerant is that it reduces the enthalpy of the liquid refrigerant remaining in the flash tank, which then expands and enters the evaporator, thus increasing the heat transferred by the evaporator and thus increasing the overall capacity and efficiency of the circuit. This effect of the economizer cycle is well known in the art of refrigeration circuits.

[0005] Alternatively, an economizer cycle may utilize an economizer heat exchanger (rather than the flash tank method described above) and operate by splitting the refrigerant flow from the condenser into a main flow and an economizer flow before any expansion occurs. The economizer flow may then be expanded by means of a heat exchanger and used to subcool the main flow before the main flow itself expands and enters the evaporator. Summary of the invention

[0006] In a first aspect, the present invention provides a condenser subassembly for providing an economizer function in a refrigeration circuit, the condenser subassembly comprising: a condenser chamber; a flash tank chamber; an expansion device; and a shell, wherein the shell defines a container, the container comprising the condenser chamber and the flash tank chamber, wherein the condenser chamber and the flash tank chamber are separated from each other by a partition in the container, and wherein the expansion device is arranged to transfer condensed refrigerant from the condenser chamber to the flash tank chamber.

[0007] Typical prior art systems with dedicated flash tank assemblies, such as those described above, take up a lot of space through piping, support frames, etc., and can be relatively expensive to implement. As proposed in the first aspect, by having a single housing and container that incorporates both the condenser chamber and the flash tank chamber, a single subassembly can perform the functions of both a condenser and an economizer. The condenser chamber and the flash tank chamber can therefore be referred to as an integrated chamber. In this way, the amount of piping required can be reduced, space can be saved, and overall installation and manufacturing costs can be reduced.

[0008] It will be appreciated that the term "refrigeration circuit" should be considered to include the circuit when used in a refrigerator (eg, a liquid cooler) or a heat pump, as the cycle is the same in both cases, only the purpose of the system is different.

[0009] The expansion device may be an internal expansion device located inside the container and the housing. By using an internal expansion device, the condenser subassembly may save additional space because associated external piping is not required. In addition, such an internal expansion device may be more robust because it is isolated from the external environment.

[0010] Alternatively, the expansion device may be an external expansion device located outside the housing. Such an external expansion device may be more easily accessible for maintenance or replacement.

[0011] The expansion device may include a float valve or other suitable valve type coupled to the liquid line from the condenser chamber to the flash tank chamber.The liquid line may be internal or external to the vessel and shell.

[0012] The expansion device may be an electronic expansion valve or an orifice device, such as a capillary tube or a float valve. Any expansion device described herein may be operable to expand liquid refrigerant flowing through the expansion device into a mixture of liquid and vapor and deliver the mixture to the flash tank chamber. In the case of an electronic expansion valve, the expansion valve may be coupled to a liquid level sensor to measure the liquid level in the flash tank chamber and adjust the opening of the electronic expansion valve accordingly.

[0013] The vessel (and shell) may be substantially cylindrical. However, those skilled in the art will recognize that the vessel may take any shape as long as it can be divided into a condenser chamber and a flash tank chamber by a partition, and the expansion device can transfer liquid between the two chambers. For example, the vessel and / or shell may have a shape known for pressure vessels, such as tubular or prismatic, including cylindrical and including forms with or without rounded ends.

[0014] The partition may separate the container into two pressure envelopes, one of which is located inside the pressure envelope of the container. For example, the container may be an outer container, and the partition may include an inner container within the outer container. The inner container may include a flash tank chamber or a condenser chamber. The inner container may be substantially cylindrical.

[0015] Alternatively, the inner container may have a substantially semi-circular cross-section.The inner container may have a cross-section that is part circular, and the cross-section may resemble a circle with a circular segment removed along the chord length.

[0016] It will be appreciated that the size and shape of the vessel may be optimized for a particular set of operating conditions of the condenser subassembly.

[0017] A portion of the outer surface of the inner container may be curved.A portion of the outer surface of the inner container may have a profile that matches the inner profile of the outer container.

[0018] The partitions may divide the container at a chord length in its cross section. The partitions may extend completely or partially along the length of the container.

[0019] By utilizing the above-described arrangement of containers and baffles, pre-existing pressure vessels from the condenser subassembly can be reused in the subassembly of the first aspect. Such a container, which may be typically cylindrical, is of course already suitable for the pressure envelope of the condenser chamber and may have pre-existing regulatory / design approvals. This provides an easier way to add economizer capabilities to an existing system without the need for an additional, completely independent pressure vessel, and potentially streamlines the design / approval process by avoiding the use of a new type of pressure vessel. For example, by adding an internal container for a flash tank chamber to the interior of an existing container with pre-existing regulatory / design approvals for the condenser assembly. Such a construction also allows the relative volumes of the container and the corresponding chamber to be easily calculated.

[0020] The partition may be reinforced or strengthened to withstand the pressure envelope of the flash tank chamber and the condenser chamber. Specifically, the partition may be reinforced or strengthened to withstand the pressure difference between the two chambers.

[0021] The housing and / or condenser chamber may include an inlet arranged to be fluidly connected to a pressure port of the compressor, and this may be via other system components such as an oil separator and / or a muffler.

[0022] The condenser chamber may include a heat exchanger arranged to cool the refrigerant in the chamber so as to condense it. The heat exchanger may include a plurality of heat exchanger tubes. The plurality of heat exchanger tubes may extend along the length of the condenser chamber. The plurality of heat exchanger tubes and the condenser chamber may form a shell and tube heat exchanger arrangement. The plurality of heat exchanger tubes may be arranged to be surrounded by the refrigerant to be condensed. However, those skilled in the art will recognize that any suitable heat exchanger may be used to cool and condense the refrigerant in the condenser chamber.

[0023] The heat exchanger tubes may be arranged to receive water and / or any other suitable coolant fluid (eg, water mixed with glycol to prevent freezing) to cool the refrigerant in the condenser chamber. The water or other suitable coolant fluid may be received from a separate refrigeration circuit.

[0024] The expansion device may be fluidly connected to a point near the bottom of the condenser chamber where condensed refrigerant will collect under gravity during use. This may be the lowest point in the condenser chamber so that any condensed refrigerant may pass to the flash tank chamber.

[0025] The condenser chamber may extend along the full length of the vessel. The flash tank may extend along the full length of the vessel. This may maximize the use of space and therefore the possible effectiveness of these components.

[0026] Alternatively, the condenser chamber and / or flash tank chamber may extend along a portion of the length of the vessel. This allows for the preservation of spare space or other components in the vessel.

[0027] For example, an oil separator may be incorporated inside the container. Thus, the container may include a condenser chamber, a flash tank chamber, and an oil separator. The oil separator may be in the oil separator chamber of the container. The oil separator may remove oil from the refrigerant flow before the refrigerant flow enters the condenser chamber.

[0028] Additionally or alternatively, a muffler may be incorporated inside the container. Thus, the container may include a condenser chamber, a flash tank chamber, an oil separator and a muffler. The muffler may be in a muffler chamber of the container.

[0029] In the case of a system employing these optional features, refrigerant flowing through the circuit from the discharge port of the compressor may pass through a muffler, then an oil separator, a condenser chamber, and then a flash tank chamber.

[0030] The flash tank chamber may include a vapor outlet and a liquid outlet. The liquid outlet may be arranged to be fluidly connected to the evaporator via another expansion device. The vapor outlet may be arranged to be connected to an economizer line and / or an economizer port of the compressor.

[0031] The flash tank chamber may include an inlet for fluid from the condenser, which inlet may be provided by the liquid pipe mentioned above.

[0032] The condenser subassembly may include a screen inside the container. The screen may be located inside the flash tank chamber. The screen may be arranged to disrupt, slow down and / or stabilize the flow path of the refrigerant to the vapor outlet and / or liquid outlet. The screen may be arranged to prevent the refrigerant liquid spray from reaching the vapor outlet. This is undesirable because only vapor should leave via the vapor outlet. In some examples, the screen blocks the line of sight between the vapor outlet and the inlet of the fluid from the condenser.

[0033] In a second aspect, the present invention provides a refrigeration circuit comprising: a condenser subassembly as described in any preceding claim; a compressor; and an evaporator; wherein the condenser subassembly has a vapor outlet and a liquid outlet, the vapor outlet being fluidly connected to an economizer port of the compressor, the liquid outlet being fluidly connected to the evaporator via an expansion device, and wherein the discharge (i.e., pressure or exhaust) port of the compressor is optionally fluidly connected to the condenser chamber via any additional intermediate member described herein.

[0034] The condenser subassembly may be attached / fixed to the compressor, thus saving more space by minimizing piping and supports between the two.

[0035] The compressor may be a multi-stage compressor. The compressor may have a lower compression stage and an upper compression stage, and the economizer port may be located at an intermediate stage therebetween. The economizer port of the compressor may be arranged between the stages of the compressor so that it receives vapor refrigerant from the flash tank. Due to the separation of vapor and liquid refrigerant in the flash tank, the remaining liquid refrigerant in the flash tank (which is then expanded and transferred to the evaporator) has a lower enthalpy, thereby increasing the capacity and efficiency of the system as previously described.

[0036] The steam outlet may be fluidly connected to an economizer port of the compressor via an economizer steam line.The economizer steam line may comprise a flow regulating valve arranged to control the flow rate of the refrigerant in the economizer line.

[0037] The flow regulating valve may be controlled by a controller. The controller may be connected to a sensor in the flash tank and / or a sensor in the compressor to measure the state of the refrigerant at the flash tank and / or the compressor. The sensor at the compressor may measure the state at the mid-level point of the compressor. The state may include temperature, pressure and / or flow rate. The flow regulating valve may be controlled based on any of these sensed states.

[0038] The evaporator may be configured to cool a gas or liquid passed thereover as the refrigerant therein is heated and evaporated.The evaporator may, for example, cool a refrigerated area such as a refrigerated compartment via the coolant fluid.

[0039] The condenser chamber may receive refrigerant from the discharge port of the compressor (optionally via any additional intermediate components described herein) and function to cool the refrigerant therein to condense it into a liquid.

[0040] The refrigeration circuit may include an oil separator arranged to remove oil from the refrigerant flow. The oil separator may be located in the refrigerant circuit between the compressor discharge port and the condenser chamber to remove oil from the refrigerant flow before the refrigerant flow enters the condenser chamber. The oil separator may be integrated into the condenser subassembly. The oil separator may be located in a container and / or a housing. Oil is usually introduced into the refrigerant in the compressor, but it should be removed before condensing the refrigerant to improve efficiency and avoid oil accumulation in the refrigeration circuit. The oil removed from the refrigerant by the oil separator may be returned to the compressor for reuse. The oil may be returned directly to the compressor, or returned to the compressor via an intermediate oil tank.

[0041] In a third aspect, the present invention provides a method of manufacturing a condenser subassembly for providing an economizer function in a refrigeration circuit, the method comprising: providing a shell, wherein the shell defines a container; providing a partition in the container; providing a condenser chamber and a flash tank chamber in the container, wherein the condenser chamber and the flash tank chamber are separated from each other by the partition in the container; and providing an expansion device, wherein the expansion device is arranged to transfer condensed refrigerant from the condenser chamber to the flash tank chamber.

[0042] The method of manufacturing a condenser subassembly may form a condenser subassembly for providing an economizer function in a refrigeration circuit according to the first aspect, including providing any of the optional features described herein.

[0043] The container (or shell) may be a pre-existing pressure vessel. The pre-existing pressure vessel may be part of an existing condenser subassembly. The method may include retrofitting a baffle to the pre-existing pressure vessel to form a condenser chamber and a flash tank chamber. In this way, a pre-existing pressure vessel that has been demonstrated to meet industry standards may be used. The container may be pre-approved for use with a pressure envelope for the condenser chamber and an optional flash tank chamber.

[0044] The method may include determining a volume of a vessel required to provide a certain economizer function in a refrigeration circuit.

[0045] The method may include determining a volume of a condenser chamber and / or a volume of a flash tank chamber required to provide a certain economizer function in a refrigeration circuit.

[0046] The method may include designing the flash tank chamber and / or the condenser chamber to fit the available volume. This may maximize the use of the available space.

[0047] The method may include determining a location and / or required strength of a baffle in the vessel so that the baffle can withstand a pressure differential between the condenser chamber and the flash tank chamber when the condenser subassembly provides certain economizer functions. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Certain exemplary embodiments will now be described, by way of example only, and with reference to the accompanying drawings, in which:

[0049] Figure 1a shows a schematic diagram of a known refrigeration circuit including a flash tank economizer;

[0050] Figure 1b A schematic diagram of a refrigeration circuit is shown, the refrigeration circuit including a condenser subassembly for providing an economizer function with an integrated flash tank chamber;

[0051] Figure 2 shows a cross-sectional view of a condenser subassembly including an integrated flash tank chamber and internal expansion device; and

[0052] Figure 3 A cross-sectional view of another condenser subassembly including an integrated flash tank chamber and an external expansion device is shown. DETAILED DESCRIPTION

[0053] refer to Figure 1a , shows a conventional refrigeration circuit 11 which includes a compressor 12, a condenser 13, a flow control device 19, a flash tank 21, an expansion device 14, and an evaporator 16 in a series flow relationship.

[0054] The compressor 12 , which functions to compress and circulate refrigerant through the refrigeration circuit, comprises a single multi-stage compressor having a lower compression stage 17 and an upper compression stage 18 .

[0055] The condenser 13 receives the refrigerant from the discharge port of the compressor 12 and functions to cool the refrigerant therein to condense it into liquid.

[0056] The evaporator 16 functions to cool the gas or liquid passing thereon when the refrigerant therein is heated and evaporates. The heated vapor is then passed to the inlet of the compressor 12.

[0057] The flow control device 19 and the flash tank 21 are disposed between the condenser 13 and the expansion device 14. The flash tank 21 together with the economizer steam line 22 fluidly interconnecting the flash tank 21 to the economizer port of the compressor 12 form part of an economizer loop.

[0058] In operation, the refrigerant leaving the condenser 13 passes through the flow control device 19, in which the refrigerant expands to reduce its pressure. The resulting mixture of liquid and vapor then enters the flash tank 21, where the liquid 24 settles to the bottom portion of the flash tank 21, and the vapor 26 remains in the top portion of the flash tank 21. The liquid refrigerant 24 is passed to the expansion device 14, where it expands, and then enters the evaporator 16.

[0059] In a process known as economizer operation, vapor 26 is passed along economizer vapor line 22 to the economizer port of compressor 12. As described above, as a result of separating the vapor and liquid refrigerant in flash tank 21, the liquid refrigerant remaining in flash tank 21 (which is subsequently expanded and passed to evaporator 16) has a lower enthalpy, thereby increasing the capacity and efficiency of the system.

[0060] The flow control device 28, which is an electronically controlled flow control device such as a solenoid valve, is controlled by the controller 29 in response to conditions sensed at the flash tank 21 and at the compressor 12. For example, the sensor S1 senses the operating conditions at the flash tank 21, and the sensor S2 senses the operating conditions at the mid-stage point 27 of the compressor 12. The sensed conditions then cause the controller 29 to open the flow control device 28 to allow energy-saving operation, or to close the flow control device 28 to turn off the economizer.

[0061] Reference now Figure 1b , shows a refrigeration circuit 111, which includes a container 112, which includes an integrated condenser chamber 113 and an integrated flash chamber 114. The structure of the container will be referred to below. Figure 2 and Figure 3 Describe in more detail.

[0062] Figure 1b The reference numerals in the table indicate the same Figure 1a The same reference numerals describe similar components.

[0063] Similar to Figure 1a In the system shown in FIG. 1 , the compressor 12 of the refrigeration circuit 111 functions to compress and circulate the refrigerant through the refrigeration circuit and includes a single multi-stage compressor having a lower compression stage 17 and an upper compression stage 18 .

[0064] The container 112 receives refrigerant from the discharge port of the compressor 12, and the refrigerant first enters a condenser chamber 113 of the container, which acts to cool the refrigerant therein to condense it into a liquid.

[0065] An expansion device (not shown) inside the vessel is arranged to transfer condensed refrigerant from the condenser chamber 113 to the flash tank chamber 114 .

[0066] The expansion device and the flash tank chamber 114 , along with the economizer steam line 22 fluidly interconnecting the vapor outlet of the flash tank chamber 114 to the economizer port of the compressor 12 , form part of an economizer loop.

[0067] In operation, the refrigerant leaving the condenser chamber 113 passes through an expansion device where the refrigerant expands, thereby reducing its pressure. The resulting mixture of liquid and vapor passes into the flash tank chamber 114 where the liquid settles to the bottom portion and the vapor remains in the top portion of the flash tank chamber (the dashed line within the flash tank chamber 114 schematically represents the boundary between liquid and vapor).

[0068] The vapor refrigerant is transferred from the vapor outlet of the flash tank chamber 114 along the economizer vapor line 22 to the economizer port of the compressor 12. As described above, as a result of separating the vapor and liquid refrigerant in the flash tank chamber 114, the remaining liquid refrigerant in the flash tank chamber 114 (which is subsequently expanded and transferred to the evaporator) has a lower enthalpy, thereby increasing the capacity and efficiency of the system.

[0069] Liquid refrigerant passes from the liquid outlet of the flash chamber 114 to the expansion device 14 where it expands and then enters the evaporator 16. Again, the evaporator 16 acts to cool the gas or liquid passing thereon as the refrigerant therein is heated and evaporates. The heated vapor then enters the inlet (suction port) of the compressor 12.

[0070] Similar to the aforementioned system, the flow control device 28, which is an electronically controlled flow control device such as a solenoid valve, is controlled by the controller 29 in response to conditions sensed at the flash tank chamber 114 and at the compressor 12. For example, the sensor S1 senses the operating conditions at the flash tank chamber 114, and the sensor S2 senses the operating conditions at the mid-stage point 27 of the compressor 12. The sensed conditions then cause the controller 29 to open the flow control device 28 to allow energy-saving operation, or to close the flow control device 28 to turn off the economizer. The controller can also control the flow rate of the refrigerant through the flow control device 28.

[0071] Now refer to Figure 2 and Figure 3 Possible configurations of the container 112 are described in more detail.

[0072] Figure 2 A cross-sectional view of a vessel 112a used as a condenser subassembly is shown. The vessel 112a is cylindrical and has a partition 115a that divides the interior of the vessel 112a into a condenser chamber 113 and a flash tank chamber 114. The partition 115a extends around the flash tank chamber 114 to form a semicircular flash tank pressure envelope.

[0073] There is a liquid pipe 116 which fluidly connects the bottom of the condenser chamber 113 to the flash tank chamber 114. This connects to a point near the bottom of the condenser chamber 113 where liquid refrigerant will collect.

[0074] Coupled to the liquid tube 116 is an internal float valve 117 which acts as an expansion device for the liquid from the condenser chamber 116 and controls the flow rate of the refrigerant from the condenser chamber 113 into the flash tank chamber.

[0075] Inside the condenser chamber 113, there are a plurality of heat exchanger tubes 118 that run axially along the length of the chamber and, in use, are surrounded by the refrigerant to be condensed. The heat exchanger tubes pass through the condenser chamber, with the refrigerant entering from the top of the condenser chamber 113 and traveling downwardly through the heat exchanger tubes 118 under the force of gravity and the pressure / flow of the refrigerant from the compressor.

[0076] There is a screen 119 in the flash tank chamber, which is located between the liquid pipe 116 and the vapor outlet 120. As described above with respect to Figure 1b As described, the steam outlet is located towards the top of the chamber and leads to the economizer steam line and the economizer port of the compressor.

[0077] As mentioned above Figure 1b As mentioned, the flash tank chamber also has a liquid outlet 121 located near its bottom, which leads to the expansion device where it expands and then enters the evaporator.

[0078] In operation, refrigerant passes from the compressor discharge port into the condenser chamber 113 where it is cooled by exchanging heat with a plurality of heat exchanger tubes 118. The heat exchanger tubes may be arranged to carry any suitable coolant fluid, such as water or some other refrigerant received from a separate refrigerant circuit.

[0079] The refrigerant in the condenser chamber 113 cools and condenses so that it collects toward the bottom of the condenser chamber 113. The float valve 117 remains open as long as the liquid level in the flash tank chamber 114 does not rise enough to push the float of the float valve upward. When the float is pushed upward by the rising liquid level in the flash tank chamber 114, the closing portion on the other end of the pivot arm of the float valve 117 reduces the size of the orifice through which the refrigerant can flow from the condenser chamber 113 to the flash tank chamber 114, thereby reducing the flow rate. The float valve is arranged to control the flow rate in this way so as to match the flow rate of the refrigerant leaving the flash tank chamber 114, thereby maintaining a substantially constant liquid level in the flash tank chamber 114.

[0080] The vessel thus includes two distinct pressure envelopes, a higher pressure envelope of the condenser chamber 113 and a lower pressure envelope of the flash tank chamber 114 .

[0081] The screen 119 in the flash tank chamber 114 slows the flow of refrigerant toward the vapor outlet so that it has time to properly expand in the flash tank chamber 114. The screen also prevents splashing or spraying of liquid refrigerant into the vapor outlet 120 to ensure that the refrigerant exiting the vapor outlet 120 is only expanding vapor and not liquid, which is undesirable.

[0082] Then, the refrigerant in the flash tank chamber 114 separates into liquid toward the bottom of the flash tank chamber 114, and vapor toward the top portion of the flash tank chamber (at Figure 2 The two phases are separated by a horizontal dashed line in the flash tank chamber 114).

[0083] As mentioned above about Figure 1b As described above, the vapor refrigerant is transferred from the vapor outlet 120 of the flash tank chamber 114 to the economizer port of the compressor along the economizer vapor line. The liquid refrigerant is transferred from the liquid outlet 121 of the flash tank chamber 114 to the expansion valve 14, where the liquid refrigerant expands and then enters the evaporator.

[0084] Figure 3 FIG. 1 shows a cross-sectional view of another container 112b used as a condenser subassembly. The container 112b includes substantially the same components and is arranged in the same manner as described above. Figure 2 114, but this vessel includes an external expansion device 122 in place of the liquid tube 116 and the internal float valve 117. Since the liquid tube 116 is no longer required, the partition 115b completely separates the interior of the vessel into the condenser chamber 113 and the flash tank chamber 114, thereby sealing the two from each other.

[0085] An external expansion device 122 is fluidly connected to a point near the bottom of the condenser chamber 113 and draws condensed liquid refrigerant from the condenser chamber, causing it to expand and pass into the flash tank chamber 114 where the refrigerant separates into liquid and vapor as previously described.

[0086] The expansion device 122 may be an electronic expansion valve, or a fixed orifice device, such as a capillary tube, all of which operate to expand the liquid refrigerant flowing through the expansion device 122 into a mixture of liquid and vapor that is delivered to the flash tank chamber 114 .

[0087] It is noted that in any of the above embodiments, the vessels 112, 112a, 112b may be formed from a pre-existing pressure vessel that has been certified to meet industry standards for use with the pressure envelope of the condenser chamber 113 (and flash tank chamber 114). Thus, any of the baffles 115a, 115b, liquid tube 116, screen 119, and float valve 117 or expansion device 122 may be retrofitted to such a pressure vessel.

Claims

1. A condenser subassembly for providing an economizer function in a refrigeration circuit, the condenser subassembly include: Condenser chamber; Flash tank room; Expansion device; as well as a shell, wherein the shell defines a container, the container including the condenser chamber and the flash tank chamber, wherein the condenser chamber and the flash tank chamber are separated from each other by a partition in the container, and wherein the expansion device is arranged to transfer condensed refrigerant from the condenser chamber to the flash tank chamber, and wherein the expansion device is an internal float valve located inside the container and coupled to a liquid pipe from the condenser chamber to the flash tank chamber; wherein the internal float valve comprises a float inside the flash tank chamber; a closed portion inside the flash tank chamber, the closed portion controlling the size of an orifice through which refrigerant may flow from the condenser chamber to the flash tank chamber; and a pivot arm connected on one end to the float and on another end to the closure portion; Wherein the float, the pivot arm and the closure portion are configured to reduce the size of the orifice when the liquid level in the flash tank chamber increases and to increase the size of the orifice when the liquid level in the flash tank chamber decreases.

2. The condenser subassembly according to claim 1, It is characterized in that The vessel is substantially cylindrical and the partition divides the vessel along its length at a chord length in cross-section thereof, or wherein the vessel is an outer vessel and the partition forms an inner vessel comprising a pressure envelope for the flash tank chamber within the pressure envelope of the outer vessel.

3. The condenser subassembly according to claim 1, It is characterized in that The condenser chamber includes a heat exchanger for cooling a refrigerant flow through the condenser.

4. The condenser subassembly according to claim 3, It is characterized in that The heat exchanger includes a plurality of tubes passing through the chamber.

5. The condenser subassembly according to claim 4, It is characterized in that The plurality of tubes are arranged to be surrounded by the refrigerant flow.

6. The condenser subassembly according to claim 1, It is characterized in that The expansion device is fluidly connected to a point near the bottom of the condenser chamber where condensed refrigerant will collect under the influence of gravity during use.

7. The condenser subassembly according to claim 1, It is characterized in that The condenser chamber extends along a complete length of the vessel, and wherein the flash tank chamber extends along at least a portion of the length of the vessel.

8. The condenser subassembly according to claim 1, It is characterized in that The flash tank chamber includes a vapor outlet and a liquid outlet, wherein the vapor outlet is arranged to be fluidly connected to an economizer loop.

9. The condenser subassembly according to claim 1, It is characterized in that The internal float valve includes a pivoting arm connected to the float on one end and to the closure portion on another end.

10. A refrigeration circuit, include: The condenser subassembly according to claim 1; compressor; as well as Evaporator; in The condenser subassembly has a vapor outlet and a liquid outlet, wherein the vapor outlet is fluidly connected to the economizer port of the compressor, the liquid outlet is fluidly connected to the evaporator via a primary expansion device, and wherein the discharge port of the compressor is fluidly connected to the condenser chamber.

11. The refrigeration circuit according to claim 10, It is characterized in that Further included is an oil separator arranged to remove oil from the refrigerant flow and / or a muffler, wherein the oil separator and / or muffler are integrated into the condenser subassembly and located within the housing.

12. The refrigeration circuit according to claim 11, It is characterized in that The oil separator and / or the muffler are inside the container.

13. A method of manufacturing a condenser subassembly for providing an economizer function in a refrigeration circuit, the method include: providing a housing, wherein the housing defines a container; providing a partition in the container; providing a condenser chamber and a flash tank chamber in the vessel, wherein the condenser chamber and the flash tank chamber are separated from each other by a partition in the vessel; and providing an expansion device, wherein the expansion device is an internal float valve, the internal float valve being arranged to couple with a liquid pipe from the condenser chamber to the flash tank chamber and to transfer condensed refrigerant from the condenser chamber to the flash tank chamber; wherein the internal float valve comprises a float inside the flash tank chamber; a closed portion inside the flash tank chamber, the closed portion controlling the size of an orifice through which refrigerant may flow from the condenser chamber to the flash tank chamber; and a pivot arm connected on one end to the float and on another end to the closure portion; Wherein the float, the pivot arm and the closure portion are configured to reduce the size of the orifice when the liquid level in the flash tank chamber increases and to increase the size of the orifice when the liquid level in the flash tank chamber decreases.

14. The method of manufacturing a condenser subassembly according to claim 13, It is characterized in that The shell is a pre-existing pressure vessel, and the method includes retrofitting the baffle to the pre-existing pressure vessel to form the condenser chamber and the flash tank chamber.

15. The method of manufacturing a condenser subassembly according to claim 13, It is characterized in that The method includes determining the volume of the vessel, the volume of the condenser chamber, and the volume of the flash tank chamber required to provide a certain economizer function in a refrigeration circuit.

16. The method of manufacturing a condenser subassembly according to claim 13, It is characterized in that The method includes determining the location and required strength of a baffle in the vessel so that the baffle can withstand the pressure differential between the condenser chamber and the flash tank chamber when the condenser subassembly provides some economizer function.

17. The method of manufacturing a condenser subassembly according to claim 13, It is characterized in that The internal float valve includes a pivoting arm connected to the float on one end and to the closure portion on another end.

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