DE102016100192B4 - Device for heat transfer - Google Patents

Abstract

Device (1) for heat transfer, in particular for heat transfer between a first fluid and a second fluid, comprising a closed housing (3) with a heat exchanger unit (2) arranged within a volume completely enclosed by the housing (3), the heat exchanger unit (2) - Is formed from tubes (10, 11, 15, 16) arranged at a distance from one another and - has at least two cylindrical spirals (9, 14) each with a central axis and at least two tubes (10, 11, 15, 16) bent in a cylindrical spiral shape, which are fluidically connected to one another via connecting elements (19) and connecting lines (20) in such a way that the first fluid flowing through the tubes (10, 11, 15, 16) in a connecting element (19) is in each case a partial mass flow through a first tube (10) and a partial mass flow is divided by a second tube (11) of the first cylindrical spiral (9) and the tubes (10, 11) of the first cylindrical Spiral (9) are acted upon by the partial mass flows in parallel, the partial mass flows after flowing out of the tubes (10, 11) merged in a connecting element (19) and through a connecting line (20) to the tubes (15, 16) of the second cylindrical Spiral (14) are passed through which the first fluid flows in series.

Description

The invention relates to a device for heat transfer, in particular for use in a motor vehicle. The heat is transferred between a first fluid and a second fluid, preferably between a liquid fluid and a refrigerant. Water or water-glycol mixtures, which absorb the heat from the refrigerant or give it off to the refrigerant, can serve as the liquid fluid. The preferred refrigerant is carbon dioxide, which is also referred to as R744 or CO2. The device has a closed housing with a heat exchanger unit arranged within a volume completely enclosed by the housing. The heat exchanger unit is formed from tubes.

Air conditioning systems for motor vehicles with refrigerant circuits and heat exchangers integrated therein are known from the prior art, the heat exchangers being operated on the one hand as evaporators and thus for cooling a fluid and on the other hand as condensers for heating a fluid. When flowing through the evaporator, the refrigerant evaporates, while it is liquefied when flowing through the condenser. The heat transfers take place with a phase change of the refrigerant.

Conventional refrigerants such as R134a and R1234yf, which have significantly lower pressures compared to carbon dioxide, circulate in the refrigerant circuit. The refrigerant cycle with R744 is also predominantly transcritical. As in processes with R134a, the heat is always absorbed when flowing through the evaporator at pressures below the critical pressure, i.e. subcritically. However, at pressures above the critical pressure, that is to say supercritically, the heat is given off to the environment.

If the refrigerant is liquefied in subcritical operation, such as with the refrigerant R134a or under certain ambient conditions with R744, the heat exchanger is referred to as a condenser. Part of the heat transfer takes place at a constant temperature. In the case of supercritical heat dissipation in the heat exchanger, the temperature of the refrigerant steadily decreases. In this case, the heat exchanger is also referred to as a gas cooler.

Gas coolers for heat transfer between R744 and the ambient air as heat-absorbing fluid correspond in design and size to conventional condensers for R134a. The installation location in the motor vehicle, in particular in the front area between the headlights, is also identical. Since essentially sensible heat has to be transferred to the air when the refrigerant flows through the gas cooler, a homogeneous flow of ambient air with the lowest possible temperature must be ensured in order to achieve a sufficiently high degree of exchange. However, a high degree of exchange and thus efficient operation of the gas cooler is becoming more and more difficult to implement with an increasing number of heat exchangers arranged in the front area of the motor vehicle, in particular for transferring the heat to the ambient air, as well as driver assistance systems.

Refrigerant-coolant heat exchangers known from the prior art, with liquid coolant as the heat-absorbing or heat-emitting fluid, for the refrigerants R134a and R1234yf are designed as plate heat exchangers. The plates made of thin-walled aluminum or sheet steel meet the strength requirements of the refrigerant at the specified pressures, for example 4 bar working pressure and 31 bar bursting pressure in the evaporator and 16 bar working pressure and 60 bar bursting pressure in the condenser. For R744 as a refrigerant, the burst pressure requirements of 260 bar in the evaporator and 340 bar in the condenser / gas cooler are many times higher.

Both the burst pressure and the operating pressure for the refrigerant R744 are up to one factor with the same temperature requirements 10 higher than with the refrigerants R134a or R1234yf. In order to meet the significantly higher strength requirements, the walls of the sheets of the plates are to be designed with significantly greater thicknesses and / or from other materials, such as stainless steel. Pressure-resistant components that meet the requirements, such as a heat exchanger made of thicker walls and / or stainless steel, are, however, very heavy and have a large installation space and are very cost-intensive to manufacture and maintain.

From the EP 2 402 694 A1 a heat exchanger, in particular a heat exchanger operated as a condenser, of an air conditioning system of a motor vehicle emerges. The condenser has a housing and a tube bundle for heat transfer between a refrigerant and a coolant, the refrigerant being conducted through the tubes of the tube bundle and the coolant being conducted through the housing. The coolant flows around the tubes on the outside. At the ends, the tubes open into elements designed as collectors. The heat exchanger is operated in cross flow. The material of the housing is plastic.

In the U.S. 5,379,832 A is a heat exchanger with a cylindrical outer surface and a cylindrical spiral tube disclosed. The cylindrical jacket surface each has a circular tubular outer wall and a circular tubular inner wall, which are arranged coaxially to one another. The space between the outer wall and the inner wall is closed at the end faces by means of end plates, so that a tubular jacket cavity is enclosed. The jacket cavity has an inlet and an outlet for a first fluid. The cylindrical pipe spiral, through which a second fluid flows, is arranged inside the casing cavity. The cylindrical tube spiral has a central axis and two tubes which are bent in a cylindrical spiral shape about the central axis and which are arranged coaxially to one another.

From the US 7 096 664 B2 shows an internal combustion engine with a heat exchanger in which a catalytic converter device for cleaning exhaust gas is integrally arranged in an exhaust duct. The heat exchanger is used to transfer heat between the exhaust gas and a working medium.

In the WO 2013/120 998 A2 describes a steam generator for a device for utilizing waste heat from an internal combustion engine, in particular in a motor vehicle. The steam generator has a heat exchanger channel, in which a heat exchanger is arranged, and a bypass channel to the heat exchanger channel. The heat exchanger channel and the bypass channel are flowed through on the one hand by a heating fluid during operation of the steam generator. On the other hand, a medium to be evaporated is applied to the heat exchanger. The heat exchanger channel can be designed to enclose the bypass channel.

A characteristic of the refrigerant heat exchangers known in the prior art is that a large installation space must be available for heat transfer with air, which space is becoming increasingly smaller, in particular in the front area of a motor vehicle. In addition, conventional heat exchangers for R134a or R1234yf have significantly lower requirements for the design pressure of the components in the refrigerant circuit compared to R744.

The object of the invention is to provide a heat exchanger for efficient heat transfer between two fluids, in particular between a refrigerant and a liquid fluid as a coolant. With the heat exchanger, it should be possible to transfer a maximum heat output with a minimum size or with a minimum space requirement. The heat exchanger should be suitable for operation with carbon dioxide. The heat exchanger should also have a minimal weight and cause minimal manufacturing and material costs.

The object is achieved by a device with the features of claim 1. Further developments are given in the dependent claims. The device is used according to claim 10.

The object is achieved by a device according to the invention for heat transfer, in particular for heat transfer between a first fluid and a second fluid. The device has a closed housing with a heat exchanger unit arranged within a volume completely enclosed by the housing. The heat exchanger unit is formed from tubes arranged at a distance from one another.

According to the conception of the invention, the heat exchanger unit has at least two cylindrical spirals each with a central axis and at least two tubes bent in a cylindrical spiral shape.
A cylindrical spiral is to be understood as a helix or a helix which is arranged as a curve with a constant slope around a jacket of a circular cylinder. The tube bent in a cylindrical spiral shape is a tube, preferably with a circular flow cross section, which describes the cylindrical spiral and is shaped in the shape of the helical line. The pipe bent in a cylindrical spiral shape is also referred to below as a pipe cylinder spiral.
The tubes bent in a spiral shape are connected to one another via connecting elements and connecting lines in such a way that the first fluid flowing through the tubes is divided in a connecting element into a partial mass flow through a first tube and a partial mass flow through a second tube of the first cylindrical spiral and the tubes of the first cylindrical spiral with the partial mass flows are applied in parallel. After flowing out of the tubes, the partial mass flows are brought together in a connecting element and passed through a connecting line to the tubes of the second cylindrical spiral, through which the first fluid flows in series.

The at least two tubes bent in a cylindrical spiral shape and connected to one another via connecting elements and connecting lines are arranged at a distance from one another and within the volume enclosed by the housing that heat can be transferred between the fluids both in the area of the tubes and in the area of the connecting elements and connecting lines.

When more than one cylindrical spiral is arranged, the central axes of the cylindrical spirals are preferably aligned parallel to one another.

According to a further development of the invention, the cylindrical spiral has at least one inner tube bent in a cylindrical spiral shape and an outer tube bent in a cylindrical spiral shape. The inner tube, which is bent in the shape of a cylindrical spiral, is arranged coaxially to the central axis of the cylindrical spiral within the volume enclosed by the outer tube, which is bent in the shape of a cylindrical spiral. The central axes of the tubes thus correspond to the central axis of the cylindrical spiral. The tube-cylinder spirals made of the inner tube and the outer tube with different diameters are joined together coaxially.

According to a preferred embodiment of the invention, guide devices are arranged within the volume enclosed by the housing, which in connection with the housing form flow paths for one of the fluids in order to guide the fluid for heat transfer through the flow paths along the outside of the tubes of the heat exchanger unit.

A separating element is advantageously arranged as a guide device between the inner tube bent in a cylindrical spiral shape and the outer tube bent in the radial direction adjacent to the central axis, so that the volume completely enclosed by the housing is divided into flow paths. The separating element is aligned coaxially to the central axis of the cylindrical spiral. The separating element is preferably designed in the shape of a hollow cylinder, in particular with a circular cross section, so that the inner tube is arranged within the volume enclosed by the separating element and the outer tube is bent in a cylindrical spiral shape around the separating element.

A further advantageous embodiment of the invention consists in the fact that a displacement element is designed as a guide device within the volume enclosed by the inner tube, which is bent in a cylindrical spiral shape. The displacement element is arranged coaxially to the central axis of the cylindrical spiral or the inner tube bent in the shape of a cylindrical spiral. The displacement element is preferably cylindrical, in particular with a circular cross section, so that the inner tube is arranged bent in a cylindrical spiral shape around the displacement element.

The flow paths are consequently delimited by the housing and the separating element as well as by the separating element and the displacement element and in each case by the outside of a pipe. The inlet and outlet of the flow paths are designed to be spaced apart from one another in the direction of the central axis, so that the fluid is guided through the flow paths essentially parallel to the central axis. The fluid can flow through the preferably at least two coaxially aligned flow paths in series or in parallel.

According to a further advantageous embodiment of the invention, the tubes are designed with ribs on the outside. The ribs, which are made of a material with excellent thermal conductivity, in particular aluminum, and increase the heat transfer surface on the outside of the tubes and are in thermal contact with the tubes, are used to generate turbulent flow and / or to coordinate the coaxial flow paths and to generate more gap-free radial dimensions preferably curved. The first fluid, specifically a refrigerant, flows inside the tubes, while a second fluid, specifically a coolant, is conducted along the ribbed outside of the tubes. The tubes are advantageously also made of a metal, in particular aluminum.

According to a further development of the invention, the housing is formed in at least two parts from a first housing element and a second housing element. It is advantageous that the housing elements are arranged in a contacting manner on a parting plane. The housing hermetically seals the heat exchanger unit from the surroundings, additional seals, in particular flat seals, advantageously being formed in the area of the parting plane between the housing elements. In the assembled state of the device, the housing elements are firmly connected to one another, preferably screwed to one another. According to alternative embodiments, the housing elements are clamped or glued or welded or crimped to one another. Crimping is a type of flanging as a joining process in which two components are connected to one another by plastic deformation. A seal, for example an O-ring seal, can be incorporated in an integrated manner within the crimped area, also referred to as a crimp.

The housing is advantageously made from a plastic or from a metal, in particular from an aluminum and / or a cast aluminum. The housing preferably has connecting pieces for conducting a fluid. The fluid can be guided into the housing through an inlet and can be guided out of the housing through an outlet. The connecting pieces advantageously protrude on both sides of a wall of the housing.

The advantageous embodiment of the invention as a device for heat transfer that can be operated in pure counterflow or in pure crossflow or in a combination of crossflow and counterflow enables use in a refrigerant circuit, in particular an air conditioning system, especially a motor vehicle, and can be used for cooling or heating a fluid a coolant circuit or a heating circuit are used. The heat exchanger unit can be used as a condenser, gas cooler or evaporator of a refrigerant, in particular carbon dioxide, in various applications, in addition to a coolant-cooled heat exchanger, for example, as a refrigerant-charged charge air cooler, exhaust gas cooler or oil cooler. Media other than refrigerants and coolants, in particular water or water-glycol mixtures, such as oil or exhaust gas, can also be used. The device for heat transfer can preferably be used as a refrigerant heat exchanger, in particular as a refrigerant-coolant heat exchanger, specifically as a carbon dioxide-water heat exchanger.

With the device according to the invention, 70% to 90% of a conventional air-cooled gas cooler can be replaced by a coolant-cooled, in particular water-cooled, gas cooler and removed from the front area of a motor vehicle in order to create a larger available space in the front area. Although installation space gained in this way is required for recooling the coolant in a coolant-air heat exchanger, all heat exchangers to be accommodated in the front region of the motor vehicle can be arranged more flexibly with respect to one another. All requirements for sensible heat transfer within the R744 gas cooler and thus for efficient operation of the air conditioning system are met. Without the possibility of relocating the gas cooler and re-cooling via a secondary coolant circuit, an efficient operation of an air conditioning system with a refrigerant circuit with carbon dioxide as the refrigerant in certain motor vehicles would not be guaranteed due to insufficient cooling or heat dissipation. In many applications, in addition to the actual engine cooling, a second coolant system is already present in motor vehicles, for example for charge air cooling or the cooling of electrical components in hybrid vehicles. This enables the coolant-cooled gas cooler to be integrated into existing second coolant systems. The additional effort for recooling the coolant is low. When using the device according to the invention as a coolant-cooled gas cooler of an air conditioning system of an electric vehicle, which can be operated in addition to the mode in refrigeration system operation also in mode in heating operation or as a heat pump, with the refrigerant circuit being switchable by means of valves, the device is used as an evaporator or as a gas cooler as required operated. If the device is integrated in the coolant circuit of the electrical components and is operated as an evaporator, the waste heat from the electrical components, for example the battery and / or the electric motor, can be upgraded and used for heating purposes.

• - effiziente Wärmeübertragung zwischen zwei Fluiden, insbesondere zwischen einem Kältemittel und einem flüssigen Fluid als Kühlmittel,
• - Übertragen einer maximalen Wärmeleistung bei einer minimalen Baugröße beziehungsweise bei minimalem Bauraumbedarf, das heißt bei optimalem Verhältnis von übertragbarer Wärmeleistung zu umbauten Volumen,
• - hoch druckfester Wärmeübertrager aus einer Kombination von mehreren parallel und/oder seriell verschaltbaren Rohr-Zylinderspiralen beziehungsweise Spiralrohrwendeln,
• - modularer Aufbau der mehreren parallel und/oder seriell verschaltbaren Rohr-Zylinderspiralen, insbesondere Rippenrohr-Zylinderspiralen, dadurch Wärmeübertrager mit minimalem Gewicht in großem Bereich der Leistung realisierbar sowie modular an Fluidkombinationen adaptierbar,
• - für den Betrieb mit Kohlenstoffdioxid, insbesondere zur Anwendung im Kraftfahrzeug, geeignet, sowie
• - minimale Kosten bei der Herstellung und minimaler Materialaufwand.

The device according to the invention has other diverse advantages:

• - efficient heat transfer between two fluids, in particular between a refrigerant and a liquid fluid as a coolant,
• - Transfer of a maximum heat output with a minimal size or with a minimal installation space requirement, i.e. with an optimal ratio of transferable heat output to built-up volume,
• - Highly pressure-resistant heat exchanger made from a combination of several parallel and / or serially connectable pipe-cylinder spirals or spiral pipe coils,
• - modular structure of the several parallel and / or serially interconnectable tube-cylinder spirals, in particular finned tube-cylinder spirals, thus heat exchangers with minimal weight in a large range of power can be implemented and modularly adaptable to fluid combinations,
• - Suitable for operation with carbon dioxide, in particular for use in motor vehicles, as well
• - minimal manufacturing costs and minimal material expenditure.

• 1: eine Vorrichtung zur Wärmeübertragung mit einem aus einem ersten Gehäuseelement und einem zweiten Gehäuseelement ausgebildeten abgeschlossenen Gehäuse,
• 2 bis 4: die Vorrichtung zur Wärmeübertragung in Schnittdarstellungen durch das Gehäuse und eine im Gehäuse angeordnete Wärmeübertragereinheit,
• 5: die Wärmeübertragereinheit der Vorrichtung zur Wärmeübertragung,
• 6a, 6b: die in dem zweiten Gehäuseelement eingebettete Wärmeübertragereinheit der Vorrichtung zur Wärmeübertragung aus 5,
• 6c: die in der zweiten Gehäuseelement eingebettete Wärmeübertragereinheit der Vorrichtung zur Wärmeübertragung aus 6a, 6b mit einer Schnittdarstellung durch die Wärmeübertragereinheit,
• 7: Explosionsdarstellung der Vorrichtung zur Wärmeübertragung mit den Gehäuseelementen und der Wärmeübertragereinheit,
• 8a: Explosionsdarstellungen der Wärmeübertragereinheit aus einer ersten und einer zweiten zylindrischen Spirale jeweils mit einem äußeren Rohr und einem inneren Rohr,
• 8b: Explosionsdarstellungen der Wärmeübertragereinheit aus 8a mit Verdrängungselementen und Trennelementen,
• 9: Rohr einer zylindrischen Spirale mit einem Anteil eines Glattrohres und einem Anteil mit Rippen sowie einer Schnittdarstellung durch den Anteil mit Rippen und
• 10: Schnittdarstellung durch eine Rohr-Zylinderspirale der Wärmeübertragereinheit.

Further details, features and advantages of the invention emerge from the following description of exemplary embodiments with reference to the associated drawings. Show it

• 1 : a device for heat transfer with a closed housing formed from a first housing element and a second housing element,
• 2 until 4th : the device for heat transfer in sectional views through the housing and a heat exchanger unit arranged in the housing,
• 5 : the heat transfer unit of the heat transfer device,
• 6a , 6b : the heat transfer unit of the device for heat transfer embedded in the second housing element 5 ,
• 6c : the heat transfer unit of the device for heat transfer embedded in the second housing element 6a , 6b with a sectional view through the heat exchanger unit,
• 7th : Exploded view of the device for heat transfer with the housing elements and the heat transfer unit,
• 8a : Exploded views of the heat exchanger unit consisting of a first and a second cylindrical spiral, each with an outer tube and an inner tube,
• 8b : Exploded views of the heat exchanger unit 8a with displacement elements and separating elements,
• 9 : Tube of a cylindrical spiral with a part of a smooth tube and a part with ribs as well as a sectional view through the part with ribs and
• 10 : Sectional view through a pipe-cylinder spiral of the heat exchanger unit.

In 1 is a device 1 for heat transfer with one of a first housing element 3a , also referred to as the upper housing half, and a second housing element 3b , also referred to as the lower housing half, formed housing 3 shown. The housing elements 3a , 3b of the two-part housing 3 are in the closed state on a parting line 4th to each other.

The first housing element 3a is designed such that it is in combination with the second housing element 3b completely encloses a volume. The first housing element 3a and the second housing element 3b correspond in the assembled state of the device 1 together. The two halves of the housing 3a , 3b can be easily plugged together and assembled.

The housing elements 3a , 3b each have a connecting piece 5 , 6th for the introduction and discharge of coolant. The coolant passes through the inlet 5 into the device 1 in and through the outlet 6th from the device 1 the end. The refrigerant flows through an inlet nozzle 7th into the device 1 and is through an outlet nozzle 8th from the device 1 derived. The inlet nozzle 7th and the outlet nozzle 8th for the refrigerant are through the wall of the first housing element 3a out of the case 3 passed through.

From the 2 until 4th goes the device 1 for heat transfer, each in a sectional view through the housing 3 and one inside the housing 3 , that is, within the from the housing 3 enclosed volume, arranged heat exchanger unit 2 emerged. The heat exchanger unit 2 is as an arrangement of finned tubes with connecting elements 19th and connecting lines 20th educated. The preferred material for the heat exchanger unit 2 is aluminum, for the housing 3 plastics are beneficial.

The case 3 seals the volume around the heat exchanger unit 2 hermetically to the environment. In the state of operation of the device 1 flows inside the heat exchanger unit 2 a refrigerant, while the heat exchanger unit 2 in addition, a liquid fluid, in particular the coolant, for example water or a water-glycol mixture, flows around it. That in the direction of flow 21 through the inlet 5 into the device 1 The coolant introduced flows into the between the walls of the housing elements 3a , 3b and the heat exchanger unit 2 formed interstices and thus on the outside of the heat exchanger unit 2 through the device 1 through and through the outlet 6th from the device 1 the end. The coolant is consequently between the components of the heat exchanger unit 2 and the inside of the case 2 in the direction of flow 21 directed. The fasteners too 19th and connecting lines 20th the heat exchanger unit 2 coolant flows around them, so that the connecting elements 19th and connecting lines 20th participate in the heat transfer between the coolant and the refrigerant.

The heat exchanger unit 2 is made up of a first cylindrical spiral 9 and a second cylindrical spiral 14th designed as two sub-units, each with two pipe-cylinder spirals arranged coaxially to one another. The first cylindrical spiral 9 and the second cylindrical spiral 14th each have an outer tube bent in a cylindrical spiral shape 10 , 15th and an inner tube bent in a cylindrical spiral shape 11 , 16 which are each arranged coaxially about a common central axis. The central axes of the first cylindrical spiral 9 and the second cylindrical spiral 14th are in turn aligned parallel to each other. The outer tubes 10 , 15th and the inner tubes 11 , 16 of the cylindrical spirals 9 , 14th are designed as finned tubes.

Between the outer tube 10 , 15th and the inner tube 11 , 16 the cylindrical spiral 9 , 14th is in each case a hollow cylindrical separating element 12th , 17th arranged. This in turn is coaxial to the common central axis of the cylindrical spiral of the inner tube 11 , 16 and the cylindrical spiral of the outer tube 10 , 15th aligned separator 12th , 17th with a circular cross-section separates this from the cylindrical spiral of the inner tube 11 , 16 surrounding volume of that of the cylindrical spiral of the outer tube 10 , 15th surrounding volume.
Inside that of the cylindrical spirals 9 , 14th and thus in the inner tube 11 the first cylindrical spiral 9 as well as in from the inner tube 15th the second cylindrical spiral 14th Each volume enclosed around the central axis is a displacement element 13th , 18th arranged. The displacement element 13th , 18th has the shape of a solid cylinder with a circular cross-section or a round rod and is coaxial to the central axis of the cylindrical spiral 9 , 14th aligned.
This makes both the first cylindrical spiral 9 as well as the second cylindrical spiral 14th designed from the inside to the outside as follows: displacement element 13th , 18th , Cylindrical spiral inner tube 11 , 16 , Separator 12th , 17th and cylindrical spiral outer tube 10 , 15th . The inner tubes 11 , 16 are each with the outer tubes 10 , 15th via connecting lines 20th and fasteners 19th fluidly connected to each other so that the of the pipes 10 , 11 , 15th , 16 Form enclosed volumes a coherent volume for the application of refrigerant.

The pipes 10 , 11 the first cylindrical spiral 9 can be flown through by the refrigerant in parallel or in series, as required, before the refrigerant passes through connecting elements 19th and connecting lines 20th to the pipes 15th , 16 the second cylindrical spiral 14th is directed. The pipes too 15th , 16 the second cylindrical spiral 14th can be flown through by the refrigerant in parallel or in series as required. In particular, a parallel flow through the pipes 10 , 11 the first cylindrical spiral 9 and / or the pipes 15th , 16 the second cylindrical spiral 14th requires precise coordination of the refrigerant flow in order to adapt the pressure losses of the refrigerant to the respective flow.
Alternatively, the outer tubes 10 , 15th parallel and then the inner tubes 11 , 16 parallel or serial or all pipes 10 , 11 , 15th , 16 refrigerant can be applied in parallel or in series.
The heat exchanger unit 2 is consequently designed in one or more rows, depending on the performance requirements, and in the number of cylindrical spirals 9 , 14th scalable. Next to the first cylindrical spiral 9 and the second cylindrical spiral 14th can consequently be provided further not shown cylindrical spirals.

With the training of the housing 3 in connection with the pipes 10 , 11 , 15th , 16 that between the pipes 10 , 11 , 15th , 16 arranged separating elements 12th , 17th and inside the cylindrical spirals 9 , 14th arranged displacement elements 13th , 18th the coolant is targeted on the outside of the heat exchanger unit 2 passed along and thus the flow through the device 1 with the coolant around the heat exchanger unit 2 in the direction of flow 21 Are defined.
The flow paths for the coolant with the deflections formed consequently result from the structural combinations in the housing 3 formed recesses, grooves and the like with that in the housing 3 integrated heat exchanger unit 2 .
Both the separating elements are special 12th , 17th as well as the displacement elements 13th , 18th , in particular in length, each designed in such a way that the mass flow of the coolant is specifically divided.

How special 3 shown, the coolant flows in the direction of flow after it has been introduced 21 through the inlet 5 and the division into two partial mass flows through the one around the outer tube 10 and the inner tube 11 the first cylindrical spiral 9 formed volumes substantially parallel to one another and parallel to the central axis of the cylindrical spiral 9 . The first partial mass flow of the coolant is between the wall of the housing 3 and the separator 12th passed through. The second partial mass flow of the coolant is between the separating element 12th and the displacement element 13th passed through. In an embodiment of the tubes (not shown) as smooth tubes, the flow paths are also wound essentially in the shape of a cylinder spiral through tubes in the shape of a cylinder spiral. In the embodiment of the tubes 10 , 11 as ribbed tubes, the flow paths run through the spaces formed between the ribs.
The displacement element 13th lies with the front sides on the housing 3 to ensure a fixed storage. The front sides of the separating element 12th protrude over the ends of the cylindrical spiral 9 , especially the ends of the cylinder spirals of the outer tube 10 and the inner tube 11 , out, with between the end faces of the separating element 12th and the case 3 A gap remains on both sides, on the one hand to divide the mass flow of the coolant as it flows in and on the other hand to bring the partial mass flows together again and as a common mass flow to the second cylindrical spiral 14th to direct.
The one after flowing around the first cylindrical spiral 9 to the second cylindrical spiral 14th directed mass flow of the coolant is between the wall of the housing 3 and the separator 17th substantially parallel to the central axis of the second cylindrical spiral 14th passed through. The front sides of the separating element 17th the second cylindrical spiral 14th protrude over the ends of the cylindrical spiral 14th , especially the ends of the cylinder spirals of the outer tube 15th and the inner tube 16 , with the separator 17th in the area of a first end face with the circumferential side on the housing 3 fluid-tight, in particular coolant-tight, is applied. The fluid-tight arrangement is used to guide the coolant around the Cylindrical spiral-shaped outer tube 15th without dividing the mass flow of the coolant. Between a second end face of the separating element arranged distally to the first end face 17th and the case 3 a gap is formed to allow the mass flow of the coolant after flowing around the outer tube 15th to the inner tube 16 redirect. After flowing out of the flow path around the outer tube 15th the second cylindrical spiral 14th the mass flow of the coolant is deflected and between the separating element 17th and the displacement element 18th through the flow path around the inner tube 16 the second cylindrical spiral 14th to the outlet 6th guided. The flow paths of the second cylindrical spiral 14th are flowed through in series.

In 5 is the heat exchanger unit 2 the device 1 shown for heat transfer. the 6a , 6b and 6c show those in the second housing element 3b , i.e. in the lower half of the housing, embedded heat exchanger unit 2 the end 5 . the end 6c goes the heat exchanger unit 2 with a sectional view through the pipes 10 , 11 , 15th , 16 of the cylindrical spirals 9 , 14th emerged.

During the operation of the device 1 flows inside the heat exchanger unit 2 the refrigerant flowing in the direction of flow 22nd through the inlet nozzle 7th into the heat exchanger unit 2 flows in and through the outlet nozzle 8th is derived. As in 5 shown, this is shown through the inlet nozzle 7th into the heat exchanger unit 2 Inflowing refrigerant in the connecting element 19th in each case a partial mass flow through the outer pipe 10 and a partial mass flow through the inner tube 11 the first cylindrical spiral 9 divided up. The pipes 10 , 11 the first cylindrical spiral 9 are acted upon in parallel with the partial mass flows of the refrigerant. After flowing out of the pipes 10 , 11 the first cylindrical spiral 9 the partial mass flows are in a further connecting element 19th merged again and through a connecting line 20th to the pipes 15th , 16 the second cylindrical spiral 14th directed.
The one after flowing through the pipes 10 , 11 the first cylindrical spiral 9 to the second cylindrical spiral 14th The directed mass flow of the refrigerant is then passed through the outer tube 15th the second cylindrical spiral 14th after flowing out of the outer tube 15th deflected and through the inner tube 16 to the outlet nozzle 8th guided. The outer tube 15th and the inner tube 16 the second cylindrical spiral 14th are flowed through serially by the refrigerant.
This means that the refrigerant side is the heat exchanger unit 2 or the device 1 for heat transfer according to the coolant side, compare the explanations 3 , connected in a pure countercurrent.

The exemplary interconnection of the refrigerant side of the device 1 for heat transfer relates specifically to a heat transfer unit operated as a gas cooler 2 , whereby the density of the refrigerant increases very sharply during cooling despite a single-phase change of state, so that the tubes 10 , 11 the first cylindrical spiral 9 parallel and the pipes 15th , 16 the second cylindrical spiral 14th flowed through in series.
The parallel flow through the first cylindrical spiral 9 and the subsequent serial flow through the second cylindrical spiral 14th the heat exchanger unit 2 is a special mode of operation especially for media without transferring latent heat. The transfer of latent heat is understood to mean a process of heat transfer in which the heat is absorbed or released during a phase transition. Examples of latent heat transfer are condensation and evaporation.
The transfer of heat without latent components takes place without a phase change in the fluid. Processes of heat transfer without a latent component take place, for example, in a heat exchanger operated supercritically as a gas cooler, in particular the present coolant-cooled or water-cooled gas cooler for carbon dioxide.

the 7th shows an exploded view of the device 1 for heat transfer with the two housing elements 3a , 3b and the heat exchanger unit 2 . From the 8a and 8b an exploded view of the heat exchanger unit 2 from the first cylindrical spiral 9 and the second cylindrical spiral 14th each with an outer tube 10 , 15th and an inner tube 11 , 16 out, in particular 8b the formation of the separating elements 12th , 17th and the displacement elements 13th , 18th made clear.

The heat exchanger unit 2 is from the housing 3 completely enclosed. The housing, which is preferably made of plastic, metal or other suitable and lightweight materials 3 is in 7th shown open. The heat exchanger unit 2 is in within the housing elements 3a , 3b trained recesses 23 arranged, which is attached to the outer shape of the cylindrical spirals 9 , 14th , Fasteners 19th and connecting lines 20th and their arrangement are adapted to one another. The two housing elements 3a , 3b are for example with one in the parting line 4th arranged flat seal screwed together. The seal and the screw connections are not shown. The connecting pieces 5 , 6th of the coolant are in each case on the housing elements 3a , 3b arranged firmly and fluid-tight. The inlet nozzle 7th and the outlet nozzle 8th of the refrigerant are through in the upper half of the housing 3a formed through openings 24 passed through and fluid-tight with the housing element 3a tied together.

8a shows the exploded view of the inner tubes 11 , 16 with each inside the cylindrical spiral 9 , 14th coaxially arranged displacement elements 13th , 18th as well as the outer tubes 10 , 15th with the inside the arrangement of the cylindrical spiral tubes 10 , 15th coaxially arranged separating elements 12th , 17th . As both the displacement elements 13th , 18th as well as the dividing elements 12th , 17th to limit the around the pipes 10 , 11 , 15th , 16 formed flow paths are used, the displacement elements 13th , 18th and the separators 12th , 17th also referred to as guide devices, especially for the coolant.
the end 8b goes the exploded view of the displacement elements 13th , 18th , the inner tubes 11 , 16 , the separating elements 12th , 17th and the outer tubes 10 , 15th out which in the assembled state of the device 1 are arranged in the order mentioned from the inside to the outside.
To complete the heat exchanger unit 2 are the connecting elements 19th and the connecting lines 20th listed.

9 shows a pipe 10 , 11 , 15th , 16 a cylindrical spiral 9 , 14th with a portion formed from a smooth tube and a portion formed with ribs as well as a sectional view through the portion formed with ribs. The part of the pipe designed as a smooth pipe 10 , 11 , 15th , 16 has an outside diameter d _a in the range of 5.5 mm to 8.2 mm ± 0.15 mm and an inside diameter d _i in the range from 4.25 mm to 4.8 mm with a wall thickness s in the range from 0.6 mm to 1.7 mm ± 10%. The outside diameter d _ar of the part designed as a finned tube is 9.4 mm, while the minimum inner diameter d _{i, min} of the finned tube is 4.0 mm. The transition between the smooth tube and finned tube has a length I. of about 15 mm.

The area of the part of the tube designed as a finned tube 10 , 11 , 15th , 16 has a minimal wall thickness s in the range from 0.6 mm to 1.1 mm. The rib height r _h is at one rib thickness r _s from 0.3 mm to 0.4 mm 1.3 mm ± 10% to 2 mm. The rib density is assumed to be 50 / (25.4 mm). In addition, dimensions of the finned tube in the range from -50% to +200% are considered suitable for the application.

the end 10 is a sectional view through a pipe-cylinder spiral of the heat exchanger unit 2 emerged.
The inside diameter D _i the cylindrical spiral of the outer tube 10 , 15th is, for example, 50.9 mm with an outer diameter d _ar of the finned tube 10 , 11 , 15th , 16 in the range of 8.8 mm ± 0.1 mm to 9.0 mm ± 0.2 mm and a distance a of the pipes 10 , 11 , 15th , 16 in the direction of the central axis of 9.4 mm.
The preferred outer diameters of the cylindrical spiral 9 , 14th are 48 mm, 69 mm, 90 mm and 111 mm with a tolerance of ± 10 mm each. With an outer diameter of the cylindrical spiral 9 , 14th of 69 mm is the inner diameter of the cylindrical spiral of the outer tube 10 , 15th 50 mm, the outer diameter of the cylindrical spiral of the inner tube 11 , 16 48 mm and the inner diameter of the cylindrical spiral of the inner tube 11 , 16 29 mm.
The number of turns per cylindrical spiral 9 , 14th is between 5 and 50.

List of reference symbols

1

Device for heat transfer

2

Heat exchanger unit

3

casing

3a

first housing element, upper housing half

3b

second housing element, lower housing half

4th

Parting plane housing 2

5

Coolant inlet, connecting piece

6th

Coolant outlet, connecting piece

7th

Inlet nozzle refrigerant

8th

Refrigerant outlet nozzle

9

first cylindrical spiral

10

outer tube first cylindrical spiral 9

11

inner tube first cylindrical spiral 9

12th

Separating element first cylindrical spiral 9

13th

Displacement element first cylindrical spiral 9

14th

second cylindrical spiral

15th

outer tube second cylindrical spiral 14

16

inner tube second cylindrical spiral 14

17th

Separating element second cylindrical spiral 14

18th

Displacement element, second cylindrical spiral 14

19th

Connecting element

20th

Connecting line

21

Direction of flow coolant

22nd

Direction of flow refrigerant

23

Recess

24

Through opening

a

distance

there

Outer diameter smooth tube 10, 11, 15, 16

represent

Outside diameter of finned tube 10, 11, 15, 16

di

Inner diameter of finned tube 10, 11, 15, 16

di, min

minimum inner diameter of finned tube 10, 11, 15, 16

Tuesday

Inner diameter cylindrical spiral outer tube 10.15

rh

Rib height

rs

Rib thickness

I.

Length transition

s

Wall thickness pipe 10 , 11 , 15th , 16

Claims (10)

Device (1) for heat transfer, in particular for heat transfer between a first fluid and a second fluid, comprising a closed housing (3) with a heat exchanger unit (2) arranged within a volume completely enclosed by the housing (3), the heat exchanger unit (2) - Is formed from tubes (10, 11, 15, 16) arranged at a distance from one another, and - Has at least two cylindrical spirals (9, 14) each with a central axis and at least two tubes (10, 11, 15, 16) bent in the shape of a cylindrical spiral, which are fluidically connected to one another via connecting elements (19) and connecting lines (20) in such a way that the The first fluid flowing through the tubes (10, 11, 15, 16) is divided in a connecting element (19) into a partial mass flow through a first tube (10) and a partial mass flow through a second tube (11) of the first cylindrical spiral (9) and the tubes (10, 11) of the first cylindrical spiral (9) are acted upon by the partial mass flows in parallel, the partial mass flows after flowing out of the tubes (10, 11) being brought together in a connecting element (19) and through a connecting line (20 ) are passed to the tubes (15, 16) of the second cylindrical spiral (14) through which the first fluid flows in series. Device (1) according to Claim 1 , characterized in that guide devices are arranged within the volume enclosed by the housing (3), the guide devices being arranged in connection with the housing (3) forming flow paths for the second fluid in such a way that the second fluid for heat transfer through the flow paths is on the outside of the To guide pipes (10, 11, 15, 16) along the heat exchanger unit (2), the second fluid being divided into two partial mass flows through the one around the first pipe (10) and the second pipe (11) of the first cylindrical spiral (9) formed volumes flows parallel to each other, is then brought together and passed to the second cylindrical spiral (14) and the flow paths of the second cylindrical spiral (14) are flowed through in series. Device (1) according to Claim 1 or 2 , characterized in that the cylindrical spirals (9, 14) each have at least one inner tube (11, 16) bent in a spiral shape and an outer tube (10, 15) bent in a spiral shape, the inner tube (11, 16) bent in a spiral shape in each case is arranged coaxially to the central axis of the cylindrical spiral (9, 14) within the volume enclosed by the outer tube (10, 15), which is bent in a cylindrical spiral shape. Device (1) according to Claim 3 , characterized in that a separating element (12, 17) is arranged as a guide device between the inner tube (11, 16) bent in a cylindrical spiral shape and the outer tube (10, 15) arranged in the radial direction adjacent to the central axis, a separating element (12, 17) as a guide device in such a way that the from Housing (3) completely enclosed volume is divided into flow paths, the separating element (12, 17) being arranged coaxially to the central axis of the cylindrical spiral (9, 14). Device (1) according to Claim 4 , characterized in that the separating element (12, 17) is designed as a hollow cylinder, so that the inner tube (11, 16) within the volume enclosed by the separating element (12, 17) and the outer tube (10, 15) in a cylindrical spiral shape around the separating element ( 12, 17) are arranged in a curved manner. Device (1) according to one of the Claims 3 until 5 , characterized in that within the volume enclosed by the inner tube (11, 16) bent in a spiral shape, a displacement element (13, 18) as a guide device is formed, wherein the displacement element (13, 18) is arranged coaxially to the central axis of the cylindrical spiral (9, 14). Device (1) according to Claim 6 , characterized in that the displacement element (13, 18) is cylindrical, so that the inner tube (11, 16) is arranged bent in a cylindrical spiral shape around the displacement element (13, 18). Device (1) according to one of the Claims 1 until 7th , characterized in that the tubes (10, 11, 15, 16) are ribbed on the outside. Device (1) according to one of the Claims 1 until 8th , characterized in that the housing (3) is constructed in at least two parts from a first housing element (3a) and a second housing element (3b). Use of the device (1) according to one of the Claims 1 until 9 for the refrigerant circuit of an air conditioning system.

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