CHILLER WITH ASYMMETRICAL INTAKE FUNNEL

Abstract

A refrigeration machine (1) with a preferably metal, ideally at least predominantly steel, housing and with an evaporator (3) for evaporating the refrigerant, an intake funnel (6), a compressor (2), and a condenser (4), wherein the intake funnel (6) collects evaporated refrigerant and supplies it to the compressor (2) connected to its discharge opening (8) along its clear cross-section, which decreases from its inlet opening (7) to its discharge opening (8), wherein the housing is divided into a first interior space and a second interior space, the first interior space being separated from the second interior space by a bulkhead (9), the evaporator (3) is arranged at least partially, in particular completely, in the first interior space, the condenser (4) is arranged at least partially, in particular completely, in the second interior space, the intake funnel (6) forms a passage that connects the first interior space to the compressor (2) in a fluid-conducting manner,and the intake funnel (6) has an inlet opening (7) whose clear cross-section has (essentially) a circular or polygonal shape with a first clear cross-sectional area (LQF1), and a discharge opening (8) whose clear cross-section has (essentially) a circular or polygonal shape with a second clear cross-sectional area (LQF2), where LQF1 > LQF2, characterized in that the heat exchanger (10) comprises heat exchanger tubes which are designed in the form of U-tubes.

Description

[0001] The invention relates to a refrigeration machine according to the preamble of claim 1. TECHNICAL BACKGROUND

[0002] Currently, compression refrigeration machines that can be used either as cooling or heating units and that use water (R718) as a refrigerant are in demand.

[0003] The cycle of such chillers typically involves the evaporation of water in a rough vacuum, the subsequent compression of the resulting water vapor in the rough vacuum, and finally the condensation of the water vapor at a higher pressure and temperature level. A so-called intake funnel is used to collect the water vapor from the evaporator and direct it to the compressor intake at a controlled, increasing velocity, despite the rough vacuum prevailing above the evaporator. Great care must be taken to ensure the intake funnel's flow-optimized design. This is because the turbocompressors driving the cycle of such chillers must handle high intake flows. Any flow separation occurring in the area of the flow funnel and the further pressure reduction encountered there therefore significantly impairs the efficiency of such a chiller.

[0004] For various reasons, it is advantageous to equip the refrigeration machine in question with an internal condenser located above the evaporator. However, such a refrigeration machine design makes the installation of the intake funnel difficult. A refrigeration machine of the rather special design in question has already been considered as an unpublished internal study, with the exhaust funnel having an elliptical cross-section that tapers continuously from bottom to top. However, the elliptical intake funnel makes installation considerably more difficult for the special design in question.

[0005] DE 10 2013 216 457 A1 describes a thermodynamic device with the following features: a first liquid container which is designed to maintain a first pressure during operation, wherein the first liquid container is partially filled with a working liquid during operation, a second liquid container which is designed to maintain a second pressure during operation, wherein the second pressure is higher than the first pressure, wherein the second liquid container is partially filled with the working liquid during operation;and a compensation tube permeable to the working fluid, which has an inlet arranged in the second fluid container to define a working fluid level in the second fluid container during operation, and which has an outlet arranged in the first fluid container so that working fluid can be transported from the inlet to the outlet through the compensation tube, wherein the inlet is arranged higher than the outlet in the installation direction, wherein the compensation tube has a curved section whose lowest region is arranged below the outlet during operation, and wherein the thermal device is designed to transport working fluid from the first fluid container to the second fluid container during operation and to transport working fluid back from the second fluid container to the first fluid container through the compensation tube.

[0006] DE 15 01 016 A describes a refrigeration machine.

[0007] The publication TGA Fachplaner 10-2004, pages 20-22, URL:https: / / www.tgafachplaner.de / sites / default / files / ulmer / detga / document / file 134009.pdf [accessed on 23.07.2021] concerns the use of water as a refrigerant. THE TASK OF THE INVENTION

[0008] In view of this, the object of the invention is to provide a refrigeration machine in which the intake funnel can be mounted more easily without having to make significant compromises in the intake efficiency. THE INVENTIVE SOLUTION

[0009] The solution according to the invention lies in a refrigeration machine that can be used as a cold or heat generator, comprising an evaporator for evaporating the refrigerant, an intake funnel, a compressor, and a condenser. The intake funnel captures evaporated refrigerant, collects it, and feeds it to the compressor connected to its discharge opening. Its clear cross-section decreases from its inlet opening to its discharge opening, such that, despite the increasing velocity of the water vapor flow toward its discharge opening, a critical negative pressure is never reached, below which flow separation is to be expected. According to the invention, the intake funnel has an inlet opening whose clear cross-section is - at least substantially - circular or preferably uniformly polygonal in shape with a first clear cross-sectional area LQF 1.In addition, the intake funnel has a discharge opening whose clear cross-section has a round or - at least substantially - a uniformly polygonal shape with a second clear cross-sectional area LQF 2. It is particularly advantageous if the clear cross-section of the intake funnel has a circular or preferably uniformly polygonal shape not only at the inlet and discharge openings, but along its predominant or entire length. In this case, LQF1 > LQF2 applies, with LQF1 preferably > 1.75 * LQF2 and, ideally, even satisfying the condition LQF1 > 2.75 * LQF2. Advantageously, the first clear cross-section and the second clear cross-section are geometrically similar, with geometrically similar being understood to mean a central extension. In other words, it is advantageous if the first clear cross-section is congruent to the second clear cross-section after scaling with a scaling factor.The scaling factor here is appropriately the factor with which a certain and, in particular, desired change in velocity of the fluid flowing through the funnel can be achieved. This certain and, in particular, desired change in velocity can preferably be determined using the Bernoulli equation and / or the continuity equation.

[0010] Circular designs of the clear cross-sections of the first and second cross-sectional areas have proven to be particularly useful, particularly due to the low pressure loss.

[0011] The evaporator and condenser are advantageously arranged as internal heat exchangers within a single housing, which usually forms a common can. The intake funnel is advantageously immersed through the condenser heat exchanger. This ensures that the vapor flow, in particular the evaporated refrigerant, does not have to undergo significant deflection, acceleration, or long flow paths, for example, in long piping systems. This minimizes pressure losses in the refrigerant, which in turn increases the efficiency of the refrigeration machine as a whole. Particularly when using water as a refrigerant, reducing pressure losses is essential for the economical operation of such a machine.

[0012] This design of the intake funnel means that, despite the large-area design of its inlet opening, it can be installed and removed relatively easily, even in confined spaces. This is because it can be rotated one or more times during installation so that the intake funnel, with its side facing the inlet opening, can be pushed past obstacles that must be passed during installation. This allows the intake funnel to be installed and removed without removing the condenser. Furthermore, the compact design enables very low pressure loss, which in turn increases efficiency compared to a state-of-the-art refrigeration machine.

[0013] The intake funnel is preferably a flow-optimized channel that guides the vapor flow, i.e., the evaporated refrigerant, from the evaporator to the impeller. Round, such as substantially circular, cross-sections are advantageous with regard to minimizing pressure losses. In a further embodiment, angular cross-sectional shapes of the intake funnel can also be used, such as 6-, 8-, or 12-sided polygons, although the pressure losses may be slightly higher here compared to round cross-sections. If polygons are used, they are preferably those that approximate a circular shape, such as 6-, 8-, or 12-sided polygons, ideally polygons in which all polygon sections are, at least essentially, the same length.

[0014] Preferably, the intake funnel extends through the second interior space. This arrangement enables a very compact design of the refrigeration machine. In particular, the refrigerant flow paths are reduced or very short. This, in turn, has the advantage of reducing pressure losses (especially further), thus increasing the efficiency of the machine.

[0015] Advantageously, the condenser comprises a heat exchanger arranged at least partially, in particular completely, in the second interior space, preferably in the form of a shell-and-tube heat exchanger, with the intake funnel penetrating the heat exchanger at least partially, in particular completely. The heat exchanger expediently comprises heat transfer tubes designed in the form of U-tubes. This allows for very effective use of the installation space.

[0016] In particular, the installation space in the area of the condenser is very well utilized.

[0017] The first interior space is expediently located below the second interior space. In particular, the cross-sections of the pipes used, in particular the connecting pipes from and to the evaporator, and / or from and to the compressor, and / or from and to the condenser, are large, and in particular, the radii are large. PREFERRED EMBODIMENT

[0018] The Fig. 1 illustrates the structure and the functional principle of the system type preferably used as a refrigeration machine or heat pump according to the invention, here using the example of the heat pump 2a with its evaporator 3 and its condenser 4 and the associated evaporator inlets and evaporator outlets 3.1 and 3.2 as well as the associated condenser inlets and condenser outlets 4.1 and 4.2.

[0019] It is a vacuum-tight system up to the heat exchangers, which may form the system boundary of the enclosed system.

[0020] It is particularly advantageous if the housing forming the so-called can is a tube or cylinder tube closed at both ends. Ideally, its longitudinal axis is positioned essentially horizontally when ready for operation. The extension of the tube along its longitudinal axis is at least a factor of 3 greater than its radius. At the same time, the extension of the tube is greater, preferably also at least a factor of 3, than the largest diameter of the intake funnel. It is the bulkhead that divides the interior of the tube into two areas that ensures the flow in the areas to the side of the mouth of the intake funnel. Ideally, shell-and-tube heat exchangers are used, which will be described in more detail later. The longitudinal axis of the heat exchanger tubes runs essentially parallel to the longitudinal axis of the tube. This ensures very effective heat exchange.The advantage of such an arrangement is that, despite the use of water as a coolant, relatively low pressure losses of the vapor can be achieved on the way from the evaporator to the compressor and from the compressor to the condenser.

[0021] This is preferably operated with pure water as the working fluid, both on the cooling fluid side and on the cold fluid side.

[0022] The cold liquid enters the evaporator 3 of the heat pump via the evaporator inlet 3.1.

[0023] Approximately 1% of the incoming cold liquid evaporates in the vacuum. The required evaporation energy is extracted from the remaining cold liquid stream KW, which thereby cools by approximately 6 °C.

[0024] The vapor W produced during evaporation is compressed by the turbocompressor 17, which is driven by an electric motor, preferably at more than 25,000 revolutions per minute to a maximum of one-third of its initial volume, increasing its pressure and temperature. It is then forced into the condenser 4.

[0025] The heated vapor W condenses in the condenser 4 directly into the circulating coolant flow K, and the condensation heat released thereby also heats the coolant flow by approximately 6 °C.

[0026] The circuit is closed via a self-regulating expansion device 18.

[0027] It is noteworthy that evaporation and recondensation take place entirely within the respective heat pump, i.e., within the box that encapsulates the heat pump from its environment. Evaporation and recondensation do not occur in the heat exchangers installed in the space to be heated or cooled and / or outside the building for the purpose of useful heat absorption or waste heat dissipation.

[0028] It should be noted in this context that the Fig. 1 does not show the heat exchangers that are preferably used within the evaporator and usually also within the condenser according to the invention. Furthermore, the figure only shows a rudimentary view of the chimney-like "intake area," within which the flow generated by the evaporator rises and is fed to the compressor's intake.

[0029] The details desirable in this regard are shown in the Fig. 2 and Fig. 3.

[0030] Good in Fig. 2 and Fig. 3 shows the suction funnel 6 according to the invention with its inlet opening 7 and its discharge opening 8. As can be seen not least from the Fig. 3, the evaporator 3 and the condenser 4 are separated from each other. However, the evaporator 3 and the condenser 4 are located within a housing of the refrigeration machine 1. In the present case, the separation is provided by the mostly horizontal, generally essentially flat bulkhead 9. It can be clearly seen that the evaporator 3 is arranged in a first interior space of the housing. The condenser 4 is arranged in a second interior space of the housing. The first interior space is separated from the second interior space by the bulkhead 9. As can be seen, the intake funnel is positioned like a chimney (without a chimney effect necessarily being achieved in all cases). It collects the rising vapor and feeds it to the radial compressor 2 arranged at its other end on its axial suction side. As can be seen, the intake funnel 6 breaks through the bulkhead 9.Its inlet opening 7 usually has a radial flange 12, usually ground on the side of its contact surface. Via this, it is usually tightly but detachably connected to the bulkhead 9. On the side of its discharge opening 8, the intake funnel has a sleeve, usually ground on its contact side, or a plug-in socket 13, usually ground on its contact side. This is used to tightly push the intake funnel onto or into the suction mouth of the radial compressor. This simplifies assembly under the spatially restricted conditions encountered here. It is noteworthy that the heat exchanger 5 of the evaporator is designed as a tube bundle heat exchanger. The longitudinal axes of the tubes of the tube bundle preferably run essentially perpendicular to the longitudinal axis L of the intake funnel.

[0031] The tube bundle of this heat exchanger, when projected onto the imaginary plane that spans the inlet opening 7 perpendicular to the intake funnel longitudinal axis L, expediently has a length LÄ and a width B - whereby, with regard to the Fig. 2 It should be noted that only half the width of the tube bundle is shown here.

[0032] The condenser 4 is preferably also equipped with a shell-and-tube heat exchanger. Ideally, the above-mentioned description of the evaporator's shell-and-tube heat exchanger applies accordingly—although with the exception that the heat exchanger 10 of the condenser 4 is divided into at least two heat exchanger components, which at least locally leave an area or window free between them. The intake funnel 6 can be pushed through this area or window to thereby contact the intake port of the compressor 2, which is located at least partially above the heat exchanger components. The heat exchanger 10 expediently comprises U-tubes.

[0033] How well in the Fig. 2 and Fig. As can be seen in Figure 3, the intake funnel 6 extends through the second interior space. The intake funnel 6 fluidically connects the first interior space with the impeller.

[0034] The Fig. 4, Fig. 5 and Fig. 6 show the intake funnel 6 according to the invention in detail. The intake funnel 6 is preferably made of a material produced by 3D printing, plastic or metal. It is therefore made of a material that is generally recognizable, at least macroscopically, by its graininess, which is, so to speak, the "footprint" of the 3D printing. This material is preferably sealed before initial use by infiltration with a suitable material or additive. Alternatively, the intake funnel 6 is produced by plastic injection molding or metal spinning.

[0035] The precise functionality and design possibilities of the intake funnel according to the invention are evident from the above, the claims, and the attached figures. Everything that can be seen in the figures is optionally relevant to the invention and can therefore also subsequently be incorporated into the claims. Fig. 3 shows the intake funnel approximately from the Fig. 2 perspective, the Fig. 4 shows it in a position rotated by 90° around the longitudinal axis L.

[0036] The reinforcing ribs 11 are also clearly visible. FINAL NOTE

[0037] Independently of the claims already made, but if necessary in combination therewith, then optionally also without reference to claim 1, protection is also claimed for a refrigeration machine with an evaporator for evaporating the refrigerant, an intake funnel, a compressor and a condenser, wherein the intake funnel collects evaporated refrigerant and supplies it to the compressor connected to its discharge opening along its clear cross-section which decreases from its inlet opening to its discharge opening, wherein the intake funnel is predominantly or substantially polygonal and / or rotationally symmetrical with respect to its longitudinal axis L.

[0038] Such protection is also claimed for an intake funnel which is instead characterized by the fact that at least its inlet opening (its clear cross-section) is non-elliptical, non-oval or non-almond-shaped and merges continuously into the rest of the intake funnel. LIST OF REFERENCE SYMBOLS 1 refrigeration machine 2 compressors 3 evaporators 3.1 Evaporator inlet 3.2 Evaporator outlet 4 condensers 4.1 Condenser inlet 4.2 Condenser outlet 5 Evaporator heat exchanger 6 intake funnels 7 Inlet opening of the intake funnel 8 Discharge opening of the intake funnel 9 bulkhead 10 Condenser heat exchanger 11 Rib of the intake funnel (stiffener) 12 Radial flange 13 Insertion socket or sleeve 14 to 15 not assigned 16 can / capsule (only in Fig. 1) 17 turbo compressors 18 Expansion organ W Steam K Coolant flow KW cold liquid flow L Longitudinal axis of the intake funnel LÄ Length of tube bundle B Width of tube bundle B / 2 half width tube bundle LQF1 first clear cross-sectional area of the intake funnel inlet opening LQF2 second clear cross-sectional area of the discharge opening of the intake funnel KL chimney longitudinal axis

Claims

[1] A refrigeration machine (1) with a preferably metal, ideally at least predominantly steel, housing and with an evaporator (3) for evaporating the refrigerant, an intake funnel (6), a compressor (2), and a condenser (4), wherein the intake funnel (6) collects evaporated refrigerant and supplies it to the compressor (2) connected to its discharge opening (8) along its clear cross-section, which decreases from its inlet opening (7) to its discharge opening (8), wherein the housing is divided into a first interior space and a second interior space, the first interior space is separated from the second interior space by a bulkhead (9), the evaporator (3) is arranged at least partially, in particular completely, in the first interior space, the condenser (4) is arranged at least partially, in particular completely, in the second interior space, the intake funnel (6) forms a passage which connects the first interior space to the compressor (2) in a fluid-conducting manner,and the intake funnel (6) has an inlet opening (7) whose clear cross-section has (essentially) a circular or polygonal shape with a first clear cross-sectional area (LQF1), and a discharge opening (8) whose clear cross-section has (essentially) a circular or polygonal shape with a second clear cross-sectional area (LQF2), where LQF1 > LQF2, , characterized by that the heat exchanger (10) comprises heat transfer tubes which are designed in the form of U-tubes. [2] Refrigeration machine (1) according to claim 1, characterized by that the intake funnel (6) protrudes through the second interior space. [3] Refrigeration machine (1) according to claim 1 or 2, characterized byin that the condenser (4) comprises a heat exchanger (10) arranged at least partially, in particular completely, in the second interior space, preferably in the form of a tube bundle heat exchanger, wherein the intake funnel (6) penetrates the heat exchanger (10) at least partially, in particular completely, and, coming from the underside of the tube bundle heat exchanger, ideally extends beyond the top side of the tube bundle heat exchanger. [4] Refrigeration machine according to one of claims 1 to 3, characterized by that the clear cross-section of the inlet opening (7) has a rotationally symmetrical or circular shape. [5] Refrigeration machine according to one of claims 1 to 4, characterized by that the clear cross-section of the discharge opening (8) has a rotationally symmetrical or circular shape. [6] Refrigeration machine according to one of claims 1 to 5, characterized bythat the clear cross-section of the inlet opening (7) is geometrically similar to the clear cross-section of the discharge opening (8), whereby geometrically similar is understood to mean a centric extension. [7] Refrigeration machine (1) according to one of claims 1 to 6, characterized by that the evaporator (3) comprises a heat exchanger (5), preferably in the form of a tube bundle heat exchanger, the base area of which, projected into the imaginary plane of the inlet opening (7) of the intake funnel (6), is longer than wide. [8] Refrigeration machine (1) according to one of claims 1 to 7, characterized by , that the condenser (4) comprises a heat exchanger (10), preferably in the form of a tube bundle heat exchanger, the base area of which, projected into the imaginary plane of the inlet opening (7) of the intake funnel (6), is longer than wide. [9] Refrigeration machine (1) according to one of the preceding claims, characterized bythat the intake funnel (6) forms a chimney which preferably tapers continuously from bottom to top, the chimney longitudinal axis (KL) of which is preferably arranged to run at least substantially vertically. [10] Refrigeration machine (1) according to one of the preceding claims, characterized by that the condenser (4) comprises several heat exchanger components and is positioned together with the heat exchanger components above the evaporator (3). [11] Refrigeration machine (1) according to one of the preceding claims, characterized by that the inner surface of the intake funnel (6) is continuously continuous in the longitudinal direction (L). [12] Refrigeration machine (1) according to one of the preceding claims, characterized by that the inner surface of the intake funnel (6) is designed in such a way that there are no points on it where the flow breaks off. [13] Refrigeration machine (1) according to one of the preceding claims, characterized bythat the inner surface of the intake funnel (6) is continuously convexly curved in the longitudinal direction (L). [14] Refrigeration machine (1) according to one of the preceding claims, characterized by that the outer surface of the intake funnel (6) is ribbed and for this purpose preferably carries ribs (11) extending in the longitudinal direction (L). [15] Refrigeration machine (1) according to claim 14, characterized by that the distance between adjacent ribs (11) measured in the circumferential direction is greater in the area of the inlet opening (7) than in the area of the discharge opening (8). [16] Refrigeration machine (1) according to one of the preceding claims, characterized by that the intake funnel (6) carries on the side of its discharge opening (8) a tubular connection collar, which preferably has a ground peripheral surface. [17] Refrigeration machine (1) according to one of the preceding claims, characterized bythat the intake funnel (6) has on the side of its inlet opening (7) a radially extending connecting flange (12), which preferably has a ground sealing surface.

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