CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of priority to Singapore Patent Application No. 10202011074Q filed on 06 November 2020, and Singapore Patent Application No. 1020210111 IX filed on 02 February 2021, the contents of it being hereby incorporated by reference in its entirety for all purposes.

TECHNICAL FIELD

[0002] The present disclosure relates to a heat exchanger system. The heat exchanger system may include one or more heat exchanger devices. The heat exchanger system may include an air-conditioner.

BACKGROUND

[0003] The following discussion of the background is intended to facilitate an understanding of the present disclosure only. It should be appreciated that the discussion is not an acknowledgement or admission that any of the material referred to was published, known or is part of the common general knowledge of the person skilled in the art in any jurisdiction as of the priority date of the invention.

[0004] Heat exchanger systems such as air-conditioners, refrigerators, or temperature regulating systems typically comprise a heat exchanger arranged in fluid communication with one or more other heat exchangers. Various forms of heat exchangers such as condenser / evaporator coils or units have been developed for such heat exchanger systems. However, most existing heat exchanger devices are relatively bulky and when implemented can produce copious amounts of heat energy, which is typically dissipated into the surrounding environment or wasted. As such, current heat exchanger systems may generate undesirable amount of heat to the environment. In addition, the chemical refrigerant used/utilized by systems such as airconditioners may adversely affect the environment and cause pollution.

[0005] In view of the global push to reduce carbon footprint, there exists a need for improved heat exchanger systems, which may include improved heat exchanger devices to provide more efficient heat exchange with reduction of carbon footprint and pollutants. SUMMARY

[0006] The disclosure was conceptualised to provide a compact and efficient heat exchanger system with a relatively lower carbon footprint and reduced pollutants.

[0007] The disclosure was also conceptualised for the application of one or more compact and efficient heat exchanger devices for a heat exchanger system to reduce the need for a conventional/chemical refrigerant (also referred to as a primary coolant) by using water or other environmentally friendly fluid(s) as a secondary coolant in the heat exchanging cycle. The compact and efficient heat exchanger devices are contemplated to facilitate heat exchange between a first fluid and a second fluid. As an example, the first fluid can be water or a fluid having water as a major constituent, and the second fluid can be a chemical refrigerant such as R410A, R134. It is contemplated that the boiling point of the second fluid is lower than the boiling point of the first fluid.

[0008] The disclosure was also conceptualised for the application of the one or more heat exchanger devices to various heat exchanger systems to reduce the need for a conventional/chemical refrigerant by using water in the heat exchange cycle, and to promote effective usage of residual heat/residual cold energy generated as part of the heat exchange cycle.

[0009] According to an aspect of the disclosure, there is a heat exchanger system comprising, a first heat exchanger comprising at least one condenser unit and at least one first evaporator unit, the at least one condenser unit arranged adjacent to the at least one first evaporator unit; a second heat exchanger comprising a second evaporator unit; a central portion positioned adjacent to at least one of the first heat exchanger and the second heat exchanger; the central portion configured to house a ventilation device; a secondary coolant tank operable to direct secondary coolant to the at least one condenser unit to cool the condenser unit; a compressor unit adapted to direct a primary coolant to the at least one condenser unit and to receive the primary coolant from the first and second evaporator units; wherein the compressor unit is suited for a low temperature and low-pressure application.

[0010] It is envisaged that the at least one condenser unit, the at least one first evaporator unit, and/or the second evaporator unit comprises a heat exchanger device which may have a double pipe configuration with double spiral portions.

[0011] In some embodiments, the heat exchanger device comprises, a first conduit having a first fluid inlet adapted to connect to a first fluid source; a second conduit contained within the first conduit or surrounded by the first conduit, the second conduit having a second fluid inlet adapted to be connected to a second fluid source; wherein the second conduit comprises a first spiral portion and a second spiral portion, the first spiral portion and the second spiral portion are arranged to maximize the surface area of the respective spiral portions exposed to the first conduit.

[0012] According to another aspect of the disclosure, there is a method of manufacturing a heat exchanger system comprising the steps of: (a.) providing a first heat exchanger, the first heat exchanger comprising at least one condenser unit and at least one first evaporator unit, the at least one condenser unit arranged adjacent to the at least one first evaporator unit; (b.) providing a second heat exchanger comprising a second evaporator unit; (c.) providing a central portion positioned adjacent to at least one of the first heat exchanger and the second heat exchanger; the central portion configured to house a ventilation device; (d.) providing a compressor unit adapted to direct refrigerant to the at least one condenser unit and to receive refrigerant from the first and second evaporator units; (e.) providing a secondary coolant container operable to direct secondary coolant to the at least one condenser unit to cool the condenser unit, wherein the compressor unit is suited for a low temperature and low-pressure application.

[0013] According to another aspect of the disclosure, there is a method of manufacturing a heat exchanger device comprising the steps of: (a.) providing a first conduit, the first conduit having a first fluid inlet adapted to connect to a first fluid source; (b.) providing a second conduit, the second conduit contained within the first conduit or surrounded by the first conduit, the second conduit having a second fluid inlet adapted to be connected to a second fluid source; wherein the second conduit comprises a first spiral portion and a second spiral portion, the first spiral portion and the second spiral portion are arranged to maximize the surface area of the respective spiral portions exposed to the first conduit.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The invention will be better understood with reference to the detailed description when considered in conjunction with the non-limiting examples and the accompanying drawings, in which:

- Figure. 1 shows an embodiment of a heat exchanger system 10;

- Figure. 2 shows another embodiment of the heat exchanger system 15; - Figure. 3 shows another embodiment of the heat exchanger system 30;

- Figure. 4a to 4c shows an embodiment of a first heat exchanger device 100;

- Figures. 5a to 5d shows an embodiment of a second heat exchanger device 200;

- Figures. 6a to 6d show various embodiments of a flow control device 300;

- Figure. 7 shows a heat exchange system 70 having one or more first and second heat exchanger devices 100, 200, and the flow control device 300;

- Figure. 8 shows a flowchart of a method 80 for manufacturing a heat exchanger system; and

- Figure. 9 shows a flowchart of a method 900 for manufacturing a heat exchanger device.

DETAILED DESCRIPTION

[0015] The following detailed description refers to the accompanying drawings that show, by way of illustration, specific details and embodiments in which the disclosure may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the disclosure. Other embodiments may be utilized and structural, and logical changes may be made without departing from the scope of the disclosure. The various embodiments are not necessarily mutually exclusive, as some embodiments can be combined with one or more other embodiments to form new embodiments.

[0016] The disclosure illustratively described herein may suitably be practiced in the absence of any element or elements, limitation or limitations, not specifically disclosed herein. Thus, for example, the terms “comprising”, “including,” containing”, etc. shall be read expansively and without limitation. The word "comprise" or variations such as "comprises" or "comprising" will accordingly be understood to imply the inclusion of a stated integer or groups of integers but not the exclusion of any other integer or group of integers. Additionally, the terms and expressions employed herein have been used as terms of description and not of limitation, and there is no intention in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the disclosure. Thus, it should be understood that although the present disclosure has been specifically described in exemplary embodiments and optional features, modification and variation of the disclosure embodied herein may be resorted to by those skilled in the art. [0017] Features that are described in the context of an embodiment may correspondingly be applicable to the same or similar features in the other embodiments. Features that are described in the context of an embodiment may correspondingly be applicable to the other embodiments, even if not explicitly described in these other embodiments. Furthermore, additions and/or combinations and/or alternatives as described for a feature in the context of an embodiment may correspondingly be applicable to the same or similar feature in the other embodiments.

[0018] In the context of various embodiments, the articles “a”, “an” and “the” as used with regard to a feature or element include a reference to one or more of the features or elements. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.

[0019] Throughout the description, the term “heat exchanger system” refers broadly to any systems capable of utilizing one or more heat exchanger devices, including, but not limited to, refrigerators and air-conditioners.

[0020] Throughout the description, the term “heat exchanger (or heat exchanger device)” may refer to a device to facilitate heat transfer between two or more fluids. Some heat exchangers described in the various embodiments can be utilized in both cooling and heating processes. It may be appreciated that a heat exchanger may include one or more interfaces. An interface of a heat exchanger may include medium to facilitate heat exchange, the interface may include a wall to achieve separation between the fluids. Such wall may be a solid wall. In some embodiments, the interface may allow the two or more fluids to be in direct contact with one another to facilitate heat exchange.

[0021] Throughout the description, the term “refrigerant” broadly includes heat exchange medium and/or fluid for facilitating heat exchange.

[0022] Throughout the description, the term “air-conditioner” includes temperature regulators for heating or cooling an environment, such as within an enclosed space/area. The term “air-conditioner” is an example of a heat exchanger system. The term “air-conditioner” may also include an outdoor system having a compressor unit and an indoor device for the regulation of temperature and/or humidity in an enclosed area. The air-conditioner includes conventional systems wherein one or more compressors are placed outdoor and portable systems wherein compressors are integrated with the blowers to form a compact unit.

[0023] Throughout the description, the terms “low temperature”, “low pressure”, “high temperature” and “high pressure” are used in association with and relative to the heat exchanger system, the heat exchanger devices, and the primary coolant. In some embodiments, the primary coolant may be a R134 refrigerant, and the term “low temperature” may include a temperature range of about 10 to 15 °C, or preferably 12.2 to 14.5 °C, and the term “high temperature” may include a temperature range of about 35 to 40 °C, or preferably 36.7 to 38 °C. The term “low pressure” may include a pressure range of about 320 to 400 kPa, i.e. 45 to 60 psig, or preferably 345 to 380 kPa, i.e. 50 to 55 psig; and the term “high pressure” may include a pressure range of about 1100 to 1200 kPa, i.e. 160 to 175 psig, or preferably 1117 to 1186 kPa, i.e. 162 to 172 psig. In some embodiments, primary coolant (refrigerant) may be a R410 refrigerant, and the term “low temperature” may include a temperature range of about 12 to 18 °C, or preferably 14 to 16 °C; and the term “high temperature” may include a temperature range of about 40 to 45 °C, or preferably about 43 °C. The term “low pressure” may include a pressure range of about 800 to 880 kPa, i.e. 115 to 128 psig, or preferably 828 to 860 kPa, i.e. 120 to 125 psig; and the term “high pressure” may include a pressure range of about 2200 to 2800 kPa, i.e. 320 to 405 psig, or preferably about 2500 kPa, i.e. 362.4 psig, In general, the exemplary values provided for “high temperature” and “high pressure” of the primary coolant has a higher temperature and pressure value, as the corresponding “low temperature” and “low pressure” of the primary coolant (refrigerant) at any given point in time.

[0024] Figure. 1 shows an embodiment of a heat exchanger system 10. The heat exchanger system 10 comprises a first heat exchanger 12 and a second heat exchanger 14.

[0025] The first heat exchanger 12 comprises at least one condenser unit 16 and at least one first evaporator unit 18. The at least one condenser unit 16 is arranged adjacent to the at least one first evaporator unit 18, and the at least one condenser unit 16 may be in thermal contact with the at least one first evaporator unit 18.

[0026] The second heat exchanger 14 comprises a second evaporator unit 20.

[0027] A central portion 22 is positioned between the first heat exchanger 12 and the second heat exchanger 14. The central portion 22 is configured to house a ventilation device 24, such as a fan or blower. The central portion 22 may further be configured to draw ambient air to pass the first heat exchanger 12 and second heat exchanger 14 so as to direct the treated air (e.g. cooled air) to be blown/blew out from the blower.

[0028] In some embodiments, the central portion 22 further houses other components such as an exhaust unit, one or more suction pumps for drawing in air, one or more controller boards that may be in the form of printed circuit boards etc. [0029] It is envisaged that although the central portion 22 is described is to be positioned between the first heat exchanger 12 and the second heat exchanger 14, the central portion 22 may be positioned adjacent to at least one of the first heat exchanger 12 and the second heat exchanger 14. In some embodiments, there may comprises additional portions similar to the central portion 22, each additional portion may comprise at least one fan mechanism operable to pushing treated air, such as cooled air, out to the ambient environment.

[0030] The heat exchanger system 10 also comprises a compressor unit 26 adapted to direct refrigerant to the at least one condenser unit 16 and to receive refrigerant from the first and second evaporator units 18, 20. The refrigerant may comprise an HFC (hydrofluorocarbon) refrigerant. The refrigerant may be regarded as a primary coolant.

[0031] In some embodiments, the HFC refrigerant used for the compressor 26 is a R134 refrigerant. It is contemplated that the refrigerant used for the compressor 26 may be a R410 refrigerant. Other refrigerants suitable for low pressure low temperature operations are contemplated.

[0032] The heat exchanger system 10 further includes a secondary coolant container, such as a water tank 27, for maintaining the temperature of the first heat exchanger 12. The water tank 27 may be filled with water (or other suitable fluid coolant). The water (or other fluid) may be regarded as a secondary coolant.

[0033] The water tank 27 may be arranged in fluid communication with a sprinkler mechanism 28. The fluid communication may be via tubes, pipes, or other conduits as known by a skilled person. A control mechanism may be arranged to direct water from the water tank 27 to the sprinkler mechanism 28. The control mechanism may include one or more mechanical control mechanisms, one or more electronic controllers, valves, or other mechanisms as known by a skilled person.

[0034] The sprinkler mechanism 28 may be suitably positioned in the proximity of the at least one condenser unit to cool the condenser unit during operation.

[0035] A fluid collector 30 may be placed in the proximity or vicinity of the first evaporator unit 18. The fluid collector 30 may be in the form of a tray, a tube, a pipe, a funnel, or combinations of the aforementioned for collection of condensed water in the proximity of the evaporator unit 18.

[0036] Most of the collected condensed water from the evaporator units 18/20 will be directed back to the water tank 27. The water around the evaporator units 18 and/or 20 condenses and falls into the fluid collector 30, which then directs the condensed water back to the water tank 27 via one or more channels or conduits.

[0037] In some embodiments, the water tank 27 comprises a channel or conduit connected externally for refill of the water tank by an external source. The refill of water tank may be performed manually by a user.

[0038] In some embodiments, the heat exchanger system 10 may include a water pump 29 (shown in Figure 7) positioned between the water source 27 and the first heat exchanger 12 and/or the second heat exchanger 14 to facilitate the flow of water at a particular flow rate to the respective heat exchangers 12, 14. The water pump is configured to pump water from/to the water source 27.

[0039] The first condenser unit 16 comprises a first condenser coil 32 and a second condenser coil 34 arranged adjoining the first condenser coil 32, and the second condenser coil 34 is arranged adjoining the at least one first evaporator unit 18. The first condenser coil 32 and the second condenser coil 34 each comprise heat exchange devices. In some embodiments, the ratio of a surface area between the first condenser coil 32 and the second condenser coil 34 may be in the range from 1:1 to 1:3. The second condenser coil 34 may comprise a plurality of coils inclined with respect to a transverse or longitudinal axis of the first heat exchanger unit 12.

[0040] Figure. 2 shows another embodiment of the heat exchanger system 15. In the embodiment shown in Figure. 2, there is an additional fluid collector 36 that may be placed in the proximity or vicinity of the second evaporator unit 20. The fluid collector 36 may be in the form of a tray, a tube, a pipe, a funnel, or combinations of the aforementioned for collection of condensed water in the proximity of the second evaporator unit 20.

[0041] Figure. 3 is another embodiment of the heat exchanger system 30. The heat exchanger system 10 shown in Figure. 3 comprises a timer 38 arranged in communication with the compressor unit, the timer 38 arranged to toggle the compressor between an on state and an off state. The timer may be set to toggle the on state and the off state based on a predetermined timing profile. The timer may include a valve timing mechanism. The predetermined timing profile comprises a ratio of on state to off state in the range of 1.5:1 to 9:1, preferably 2:1 to 9:1 and preferably 7:3. It is appreciable that the timer 38 may also be incorporated in the embodiment shown in Figure. 1. [0042] In some embodiments, the first condenser coil 32 comprises a first heat exchanger device 100, and the second condenser coil 34 comprises a second heat exchanger device 200. It is contemplated that the first condenser coil 32 may comprise a second heat exchanger device 200, and the second condenser coil 34 may comprise a first heat exchanger device 100. It is further contemplated that the first condenser coil 32 and the second condenser coil 34 comprise condenser coils as known by a skilled person.

[0043] Figures 4a to 4c show an embodiment of a first heat exchanger device 100. The first heat exchanger device 100 comprises a first conduit 120 having a first fluid inlet (water inlet) 120a adapted to connect to a secondary coolant (e.g. water) source (not shown); a second conduit 160 contained within the first conduit 120 or surrounded by the first conduit 120, the second conduit 160 having a second fluid inlet (refrigerant) 160a adapted to be connected to a refrigerant source (not shown); wherein the second conduit 160 comprises a first spiral portion 160c and a second spiral portion 160d, the first spiral portion 160c and the second spiral portion 160d are arranged to maximize the surface area of the respective spiral portions exposed to the first conduit 120.

[0044] As shown in Figure 4c (plan view), the second spiral portion 160d may be circumferenced or surrounded by the first spiral portion 160c. The second spiral portion 160d may be partially or completely surrounded by the first spiral portion 160c.

[0045] The water inlet 120a and the refrigerant inlet 160a may be positioned on opposing ends 100a, 100b of the first heat exchanger device 100, respectively. Correspondingly there is a water outlet 120b positioned at the end 100b and a refrigerant outlet 160b positioned on the end 180a of the heat exchanger device.

[0046] In some embodiments unlike that shown in Figures 4a to 4c, the water inlet 120a and the refrigerant inlet 160a may be positioned on the same end 100a of the first heat exchanger device 100. Correspondingly, the water outlet 120b and the refrigerant outlet 160b may be positioned on the opposite end 100b of the first heat exchanger device 100.

[0047] Ends 100a, 100b may be covered and sealed by caps so that when in use, for example when water is flowing within the first conduit 120, leaks are minimized and preferably prevented.

[0048] At least one of the first conduit 120 and second conduit 160 may be formed of or formed from copper. [0049] At least one of the water inlet 120a and water outlet 120b may be a 12.7 millimeters (mm), i.e. 0.5 inch diameter pipe. At least one of the refrigerant inlet 160a and refrigerant outlet 160b may be a 6.35 mm, i.e. 0.25 inch diameter pipe.

[0050] Each of the spiral portions 160c, 160d may be a pipe arranged to form respective helical coils. Each of the formed helical coils may include a predetermined number of turns. In some embodiments, the number of turns may range from 10 to 50. In some embodiments, the predetermined turns may be 30 turns. The internal diameters of the pipes 160c, 160d which define the hollow portion of the pipe may be of a smaller diameter relative to the refrigerant inlet 160a and refrigerant outlet 160b so as to facilitate capillary action/effect when the second fluid is flowing through the spiral portions 160c, 160d. In some embodiments, the inner diameter of the spiral portions 160c, 160d may be 3.18 mm, i.e. 0.125 inch or 4.76 mm, i.e. 0.1875 inch.

[0051] The first conduit 120 may have an inner diameter of 102 mm, i.e. 4 inches to accommodate the second conduit 160. The first conduit 120 may be shaped as a hollow pipe having a length of 350 mm, i.e. 13.8 inches. The second conduit 160 may be contained within the hollow pipe of the first conduit 120, thereby forming a multi-pipe configuration, to achieve overall compactness of the heat exchanger device 100.

[0052] In use, the first fluid flows within the first conduit 120, and the second fluid flows within the second conduit 160. The first fluid contacts the surface of the first spiral portion 160c and the second spiral portion 160d such as to facilitate heat transfer at least via conduction. In configurations where the inlets 120a, 160a are positioned at opposing ends, it is contemplated that the flow of the first fluid may be at an opposite direction from the second fluid. In configurations where the inlets 120a, 160a are positioned at the same end, it is contemplated that the flow of the first and second fluid may be in the same direction. It is also contemplated that the flow rates of the first fluid and second fluid may be adjustable such that the first fluid (water) flows at a faster rate than the flow rate of the second fluid (refrigerant).

[0053] In some embodiments, the flow rate of the first fluid (water) is at least 7000 litres per hour. The flow rate of the second fluid (refrigerant) may be at a fraction of the first fluid.

[0054] Figures 5a to 5d show an embodiment of a second heat exchanger device 200. The second heat exchanger device 200 comprises a first conduit 220 having a first fluid (e.g. water) inlet pipe 220a adapted to connect to a water source (not shown); a second conduit 240 contained within or surrounded by the first conduit 220; the second conduit 240 adapted to connect to a refrigerant source (not shown); wherein the second conduit 240 comprises a first spiral portion 260 and a second spiral portion 280, the first spiral portion 260 and the second spiral portion 280 are arranged to maximize the surface area of the respective spiral portions exposed to the first conduit 220.

[0055] The first spiral portion 260 and the second spiral portion 280 may be arranged in a manner such that they are displaced or offset from each other. The displacement or offset may be such that a body portion of the first spiral portion 260 overlaps with a body portion of the second spiral portion 280. As apparent from the drawings, the second spiral portion 280 is not contained or surrounded by the first spiral portion 260 (unlike that of the first heat exchanger device 100).

[0056] A water inlet 220a and a refrigerant outlet 260b of the first spiral portion 260 may be positioned on opposing ends 200a, 200b of the second heat exchanger device 200 respectively. A refrigerant inlet 280a of the second spiral portion 280 may be positioned on the same end 200a as the water inlet 220a.

[0057] Correspondingly, a water outlet 220b, a refrigerant inlet 260a of the first spiral portion 260, and a refrigerant outlet 280b of the second spiral portion may be positioned on the end 200b of the second heat exchanger device 200.

[0058] Although the refrigerant inlets 260a, 280a are positioned on opposite ends of the second heat exchanger device 200, it is contemplated that the refrigerant inlets 260a, 280a may be positioned on the same end 200a, 200b.

[0059] Accordingly, although the refrigerant outlets 260b, 280b are positioned on opposite ends of the second heat exchanger device 200, it is contemplated that the refrigerant outlets 260b, 280b may be positioned on the same end 200a, 200b.

[0060] At least one of the first conduit 220 and second conduit 260 may be formed of or formed from copper.

[0061] At least one of the water inlet 220a and water outlet 220b may be a 12.7 mm, i.e. 0.5 inch diameter pipe. At least one of the refrigerant inlets 260a, 280a and refrigerant outlet 260b, 280b may be a 6.35 mm, i.e. 0.25 inch diameter pipe.

[0062] Each of the spiral portions 260, 280 may be a pipe arranged to form respective helical coils. Each of the formed helical coils may include a predetermined number of turns. In some embodiments, the number of turns may range from 10 to 50. In some embodiments, the predetermined number of turns may be 30 turns. The internal diameters of the pipes 260, 280 which define the hollow portions of the pipes may be of a smaller diameter relative to the refrigerant inlets 260a, 280a and refrigerant outlets 260b, 280b so as to facilitate capillary action/effect when the second fluid is flowing through the spiral portions 260, 280. In some embodiments, the inner diameter of the spiral portions 260, 280 may be 3.18 mm, i.e. 0.125 inch or 4.76 mm, i.e. 0.1875 inch.

[0063] The first conduit 220 may have an inner diameter of 102 mm, i.e. 4 inches to contain the second conduit 240. The first conduit 220 may be shaped as a hollow pipe having a length of 350 mm, i.e. 13.8 inches. The body of the second conduit 240 may be completely contained within the hollow pipe of the first conduit 220 to achieve overall compactness of the second heat exchanger device 200.

[0064] In use, the first fluid (e.g. water) flows within the first conduit 220, and the second fluid (e.g. refrigerant) flows within the second conduit 240. The first fluid contacts the surface of the first spiral portion 260 and the second spiral portion 280 such as to facilitate heat transfer at least via conduction. In configurations where the inlets 220a, 260a are positioned at opposing ends, it is contemplated that the flow of the first fluid may be at an opposite direction from the second fluid. Where the inlets 220a, 280a are positioned at the same end, it is contemplated that the flow of the first fluid is in the same direction as the second fluid.

[0065] It is also contemplated that the flow rates of the first fluid and second fluid may be adjustable such that the first fluid (water) flows at a faster rate than the second fluid (refrigerant). The faster rate (water) may be double the rate of the slower rate (refrigerant).

[0066] In some embodiments, the flow rate of the first fluid (water) is less than or equals to 7000 litres per hour.

[0067] Figure 6a to 6d shows various embodiments of a flow control device 300. Figure 6a shows an embodiment of the flow control device 300. The flow control device 300 may comprise a plurality of capillary tubes. The flow control device 300 may include a first end 300a and a second end 300b opposing the first end 300a. The flow control device 300 may comprise a first capillary tube 320 and a second capillary tube 340 arranged adjacent to the first capillary tube 320. In some embodiments, the first and second capillary tubes 320, 340 are spaced apart from each other. The first capillary tube 320 and the second capillary tube 340 may not be linked or connected to each other. The first capillary tube 320 may be spaced apart from the second capillary tube 340 by a distance of 0.5 mm, i.e. 0.02 inch. [0068] A portion of the first and second capillary tubes 320, 340 may be arranged to form a helical coil 360. The helical coil 360 may include a predetermined number of turns, the turns may range from 5 to 20. In some embodiments, the predetermined turns may be 7 turns. The helical coil 360 may have a coil pitch ranging from 2 to 5 °. In some embodiments, the coil pitch may be 3.64 °. The helical coil 360 may have a length (across the longitudinal axis of the helical coil 360) ranging from 20 to 50 mm. In some embodiments, the length of the helical coil 360 may be 32 mm. When the portion of the first and second capillary tubes 320, 340 are arranged to form the helical coil 360, the first and second capillary tubes 320, 340 may be in contact with each other, and may be arranged adjoining each other due to the compactness of the helical coil 360. It is contemplated that the first and second capillary tubes 320, 340 may not be in contact with each other when they are arranged to form the helical coil 360.

[0069] Figures 6b to 6d show another embodiment of the flow control device 300. The flow control device 300 shown in Figures 6b to 6d comprises a casing 380, the casing 380 adapted to enclose the helical coil 360. The casing 380 may include a material with sufficient durability to enclose and hold the helical coil 360, and/or a material with sufficient thermal conduction. In some embodiments, the casing may include polyvinyl chloride, or may include metallic heat conductors such as iron, aluminum, copper, or alloys. The casing 380 holds and maintains the shape and compactness of the helical coil 360 such that the diameter across opposing ends of the helical coil 360 is uniform. In addition, the casing 380 may protect the helical coil 360 from damage. As such, obstruction of the second fluid (refrigerant) flowing through the helical coil 360 may be minimized or preferably prevented. In some embodiments, the casing 380 may further include a protective cover around the casing 380. The cover may protect the casing 380 enclosing the helical coil 360 from damage.

[0070] The casing 380 may be adapted to allow air to flow through the casing 380, and may further include ventilation holes and/or channels. In use, a second fluid (refrigerant) flows within the first and second capillary tubes 320, 340 and the helical coil 360 of the flow control device 300 to send the second fluid (refrigerant) to the at least one first evaporator unit 18, and the second evaporator unit 20. The flow control device 300 may be used to control the flow of the second fluid (refrigerant) to the at least one first evaporator unit 18 and the second evaporator unit 20. The air flowing through the casing 380 may facilitate heat transfer at least via convection, and may minimize or preferably prevent flashing (also known as “flash-gas)” of the second fluid (refrigerant) flowing through the helical coil 360. [0071] In some embodiments, the casing 380 may be a water-proof and water-tight casing 380. The casing 380 may enclose and seal the helical portion 380 of the flow control device 300 such that when in use, for example when a fluid is flowing within the casing 380, leaks are minimized and preferably prevented. The casing 380 may include a fluid inlet 382a positioned on a first side 380a of the casing 380, and a fluid outlet 382b positioned on a second side 380b of a second side 380b of the casing 380. The first side 380a may be opposite to the second side 380b. The fluid inlet and outlet 382a, 382b may each comprise a hole or aperture with a predetermined diameter, the diameter ranging from 5 to 10 mm. In some embodiments, the predetermined diameter may be 8 mm.

[0072] The casing 380 may be connected to or arranged in fluid communication with a fluid source, and the fluid communication may be via tubes, pipes or other conduits as known by a skilled person. The fluid may include water and the fluid source may be the water tank 27. In some embodiments, the fluid may be a fluid which has a boiling point similar to or lower than that of water, such as, but not limited to, an alcohol. It is contemplated that the fluid may include a mixture of water and the fluid which has a boiling point similar to or lower than that of water. The fluid inlet 382a may be adapted to receive the fluid from the fluid source, and the fluid outlet 382b may be adapted to release the fluid from the casing 380, which may be released into the fluid source. In some embodiments, a water-tight rubber grommet may surround the fluid inlet 382a and the fluid outlet 382b, to provide a seal to receive the tube, pipe or other conduits which provide or release the fluid to or from the casing 380.

[0073] In use, the fluid (water and/or a fluid having similar or lower boiling point than water) may flow within the casing 380 enclosing the portion comprising the helical coil 360 of the flow control device 300. The fluid (water and/or fluid having similar or lower boiling point than water) contacts the helical coil 360 containing the second fluid (refrigerant), and may facilitate heat transfer at least via conduction, and may minimize or preferably prevent flashing (also known as “flash-gas”) of the second fluid (refrigerant).

[0074] The casing 380 may also include a first opening 386a positioned on the first side 380a of the casing 380, and a second opening 386b positioned on the second side 380b of the casing 380. Both the first and second openings 386a, 386b may be adapted to surround the first and second capillary tubes 320, 340. The first and second openings 386a, 386b may receive the first and second capillary tubes 320, 340 adjacent to the helical coil 380 portion, such that the helical coil 360 may be enclosed by the casing 380 and the remaining portions of the first and second capillary tubes 320, 340 may be exposed.

[0075] At least one of the first opening 386a or the second opening 386b may comprise an angled opening (see detail labelled “C” in Figure 6d). In some embodiments, both the first and second openings 386a, 386b comprise angled openings. The angled opening may be configured such that the first and second capillary tubes 320, 340 enters and/or exits the first and/or second openings 386a, 386b at an angle. The first and second capillary tubes 320, 340 may abut or meet the interface of, the first and/or second openings 386a, 386b at an angle, the angle may be an acute angle and may be less than 90 °. In some embodiments, the angle may be 66 °.

[0076] In some embodiments, the flow control device 300 may be equipped with one or more pressure and/or temperature sensors.

[0077] The first and second heat exchanger devices 100, 200, and the flow control device 300, may be deployed in a heat exchanger system such as an air-conditioner system. Figure 7 shows an example of the use of the first and second heat exchanger devices 100, 200, and the flow control device 300 in the heat exchanger system 10, 15, 30, which may be in the form of an air-conditioner system 70. Referring to Figures 1 to 7, the air-conditioner system 70 comprises the at least one condenser unit 16, the at least one first evaporator unit 18 arranged adjoining the at least one condenser unit 16, the compressor 26 providing a refrigerant source, e.g. R134 refrigerant, the water tank 27, and a refrigerant flow control device 300.

[0078] The first condenser coil 32 can be one or more first heat exchanger devices 100 as described with reference to Figures 4a to 4c, and the second condenser coil 34 can be one or more second heat exchanger devices 200 as described with reference to Figures 5a to 5d. The flow control device 300 can be the flow control device 300 as described with reference to Figures 6a to 6d. As shown in Figure 7, the first condenser coil 32 comprises two first heat exchanger devices 100, and the second condenser coil 34 comprises two second heat exchanger devices 200.

[0079] The water inlet 120a of each of the first heat exchanger devices 100 can be connected to the water tank 27, and the water outlet 120b of each of the first heat exchanger devices 100 can be connected to the second heat exchanger devices 200. Specifically, the water outlet 120b of each of the first heat exchanger devices 100 can be connected to the water inlet 220a of each of the second heat exchanger devices 200 (as shown in Figure 7), such that the first 100 and second 200 heat exchanger devices are linked. The inlet for the refrigerant 160a of each of the first heat exchanger devices 100 can be connected to the compressor 26, and the outlet of the refrigerant 160b of each of the first heat exchanger devices 100 can be connected to one or more flow control devices 300 towards the at least one first evaporator unit 18, and second evaporator unit 20 (not shown). The evaporator units 18, 20 may include one or more evaporator coils.

[0080] The water outlet 220b of each second heat exchanger devices 200 can be connected back to the water tank 27. Alternatively, the water inlet 220a of each second heat exchanger device 200 can be connected to the water tank 27, and the water outlet 220b of each of the second heat exchanger device 200 can be connected to the water outlet 120b of each of the first heat exchanger device 100 (not shown in Figure 7). The inlets for the refrigerant 260a, 280a of each of the second heat exchanger devices 200 can be connected to an outlet of the first evaporator unit 18, and the outlets for the refrigerant 260b, 280b of each of the second heat exchanger devices 200 can be connected to the compressor 26.

[0081] In operation, the compressor 26 functions as a refrigerant source and is configured to provide refrigerant through the air-conditioner system 40. The compressor 26 pumps the refrigerant through the air conditioning system 40 at a predetermined flow rate and pressure. When the refrigerant enters the compressor 26, it is typically in a relatively low-pressure vapour state at a temperature above room or ambient temperature. The refrigerant enters the compressor 26 under a suction force and is compressed into a high pressure vapour. The compressed refrigerant exits the compressor 26 under a relatively higher temperature than when it enters the compressor 26.

[0082] The compressor 26 is arranged in fluid communication to send refrigerant to the first and second heat exchanger devices 100, 200. The water tank 27 is arranged in fluid communication with the first and second heat exchanger devices 100, 200 to send water to the first and second heat exchanger devices 100, 200. Such an arrangement is configured for heat exchange to take place between the relatively high-pressure high-temperature refrigerant vapour and the water, with the objective of cooling the refrigerant using water from the water tank 27. Thereafter, water that gains heat from the refrigerant is either evaporated or directed back to the water tank 27 due to condensation onto the first evaporator unit/coils 18 arranged adjacent (and in contact) with the second heat exchange device 200. As the refrigerant is cooled, it changes from the gaseous state to a liquid state. [0083] The cooled refrigerant is sent from the first and second heat exchanger devices 100, 200 to the first and second evaporator units 18, 20 (second evaporator unit 20 is not shown) via the flow control device 300, which may comprise the first and second capillary tubes 320, 340. A first end 300a of the flow control device 300 can be connected to the refrigerant outlet 160b of each of the first heat exchanger devices 100, and a second end 300b of the flow control device 420 can be connected to the first evaporator unit 18, such that the cooled refrigerant can be sent from each of the first heat exchanger devices 100 to an inlet, e.g. refrigerant inlet on the first evaporator unit 18. In some embodiments, an additional flow control device 300 comprising the first and second capillary tubes 320, 340 may also be provided to send cooled refrigerant from each of the second heat exchanger devices 200 to the second evaporator unit 20 (not shown). A first end 300a of the flow control device 300 can be connected to the refrigerant outlet 260b, 280b of the second heat exchanger devices 200 and a second end 300b can be connected to an inlet, e.g. refrigerant inlet on the second evaporator unit 20.

[0084] The flow control device 300 controls the flow of the cooled liquid refrigerant to the first and second evaporator units 18, 20. The flow control device 300 is operable to control the flow of the refrigerant such that as the high-pressure refrigerant passes through the flow control device 300, and into the first and second evaporator units 18, 20 the pressure of the refrigerant drops. It is contemplated that the flow control device 300 may be replaced by a conventional capillary tube or capillary tube arrangement.

[0085] After exiting the flow control device 300, the refrigerant enters the first and second evaporator units 18, 20. The evaporator units 18, 20 may be positioned adjacent to the central portion 22 (as shown in Figure 1) which includes a ventilation device, such as a fan which may blow across the first and second evaporator units 18, 20 to facilitate heat transfer between the cooled refrigerant and the ambient environment. As the refrigerant enters the coil at a lower pressure it begins to boil and change state back to a vapour. During this process of changing state from liquid to vapour, energy in the form of heat is removed from the ambient air passing over the first and second evaporator unit 18, 20 and the heat from the ambient environment is absorbed by the refrigerant. The heat that was in the ambient air is transferred into the refrigerant, thereby cooling the ambient environment.

[0086] After the refrigerant (that has absorbed some heat energy from the ambient environment) passes through the first and second evaporator units 18, 20 and exits the same, the temperature of the refrigerant may be relatively lower compared to the temperature of the air in the vicinity of the first and second evaporator units 18, 20. As such, water may condense on the first and second evaporator coils within the evaporator units 18, 20, The evaporator units 18, 20 also includes the fluid collectors 30, 36 to collect condensate from the ambient environment, i.e. condensed water in the proximity of the first and second evaporator units 18, 20.

[0087] Similarly, the temperature of the refrigerant may also be relatively lower compared to the temperature of the water in the water tank 27. In some embodiments, the second heat exchanger device 200 is used to receive the refrigerant (from the first evaporator unit 18) to facilitate heat exchange between the refrigerant and the water from the water tank 27. In other words, the residue coolness of the refrigerant is used to cool the water before the refrigerant flows back to the compressor 26.

[0088] A water pump 29 may be positioned between the water tank 27 and the first and second heat exchanger devices 100, 200 to facilitate the flow of water at a particular flow rate to the respective first and second heat exchanger devices 100, 200. The water pump 29 is configured to pump water from/to the water tank 27.

[0089] In some embodiments, one or more connecting pipes (not shown) may be utilized to connect the different spiral portions of the first 100 and second 200 heat exchanger devices to the refrigerant source (e.g. compressor 26). The connecting pipes may be arranged to combine the flow of refrigerant from the spiral portions 160c, 160d or the spiral portions 260, 280 to the refrigerant source. One or more connecting pipes (not shown) may also be utilized to connect the different evaporator coils and/or to the refrigerant source (e.g. compressor). The connecting pipes may be arranged to combine the flow of refrigerant to/from the refrigerant source.

[0090] It is contemplated that the flow rates may be reduced where a plurality of first and second heat exchanger devices 100, 200 are combined in various combinations. For example, in the embodiments where the first and second heat exchanger devices 100, 200 are used in the air-conditioner system 70, the flow rate in each of the first and second heat exchanger devices 100, 200 may be reduced by up to 50%.

[0091] In some embodiments, in addition to the water tank 27, the air-conditioner system 70 may include at least one auxiliary container. The at least one auxiliary container may be used to store water and may be arranged in fluid communication with the water tank 27 (via one or more pipes for example) so as to regulate the temperature of water in the water tank 27 within a permissible range. A controller assembly comprising an electronic controller and one or more valves may be arranged to control flow of water from the auxiliary container to the water tank 27. The electronic controller may activate the opening of the one or more valves periodically to allow flow of water from the auxiliary container into the water tank 27. The water tank 27 may comprise a channel or conduit to allow the flow of water from the external auxiliary container into the water tank 27.

[0092] It is contemplated that the at least one first evaporator unit 18 and/or the second evaporator unit 20 can be one or more first heat exchanger devices 100. It is further contemplated that the at least one first evaporator unit 18 and/or the second evaporator unit 20 can be one or more second heat exchanger devices 200. In some embodiments, the first and second heat exchanger devices 100, 200 may be interchangeable, and it is further contemplated that the at least one first evaporator unit 18 and/or the second evaporator unit 20 can be one or more first and second heat exchanger devices 100, 200.

[0093] According to another aspect of the disclosure and with reference to Figure 8 there is a method 80 for manufacturing a heat exchanger system comprising the steps of

(a.) providing a first heat exchanger, the first heat exchanger comprising at least one condenser unit and at least one first evaporator unit, the at least one condenser unit arranged adjacent to the at least one first evaporator unit (step S82);

(b.) providing a second heat exchanger comprising a second evaporator unit (step S84);

(c.) providing a central portion positioned between the first heat exchanger and the second heat exchanger; the central portion configured to house a ventilation device (step S86);

(d.) providing a compressor unit adapted to direct refrigerant to the at least one condenser unit and to receive primary coolant (in the form of a refrigerant) from the first and second evaporator units; wherein the compresser unit is suited for a low temperature and low- pressure application; and wherein the refrigerant comprises a HFC (hydrofluorocarbon) refrigerant, such as a R134 refrigerant (step S88);

(e.) providing a secondary coolant tank, such as a water tank operable to direct water to the at least one condenser unit to cool the condenser unit.

[0094] The heat exchanger system may be the heat exchanger system 10, 15, 30, 70 (in the form of an air-conditioner) as described with reference to the embodiments shown in Figures 1 to 3, and in Figure. 7.

[0095] According to another aspect of the disclosure there is a method for manufacturing 900 a heat exchanger device comprising the steps of (a.) providing a first conduit, the first conduit having a first fluid inlet shaped and dimensioned to connect to a first fluid source (S902);

(b.) providing a second conduit, the second conduit contained within the first conduit or surrounded by the first conduit, the second conduit having a second fluid inlet shaped and dimensioned to be connected to a second fluid source; wherein the second conduit comprises a first spiral portion and a second spiral portion, the first spiral portion and the second spiral portion are arranged in the form of a helical coil (S904).

[0096] In some embodiments, the step of providing the second conduit includes providing a first hollow pipe and forming the first hollow pipe into a first helical coil, thereby forming the first spiral portion; providing a second hollow pipe and forming the second hollow pipe into a second helical coil, thereby forming the second spiral portion; and inserting the second helical coil into the first helical coil.

[0097] In some embodiments, the steps of forming the first hollow pipe and/or the second hollow pipe into the respective first helical coil and/or second helical coil includes making a predetermined number of turns on the first hollow pipe and/or second follow pipe. The predetermined number of turns may be 30.

[0098] The heat exchanger device may be the first heat exchanger device 100, or the second heat exchanger device 200 as described with reference to the embodiments shown in Figures 4 and 5.

[0099] It is envisaged that the heat exchanger system 10, 15, 30, 70 comprising one or more first and second heat exchanger devices 100, 200 may be an air-conditioner, a refrigerant, an air ventilator, a de -humidifier. It is envisaged that the air-conditioner unit may be a portable air-conditioner unit 70, for example, wherein the various components as described above being housed in one housing.

[00100] While the disclosure has been particularly shown and described with reference to specific embodiments, it should be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. The scope of the invention is thus indicated by the appended claims and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced.