Chiller with compression refrigerant circuit and buffer storage, a corresponding cooling arrangement and a corresponding operating procedure

Abstract

Chiller for cooling a liquid cooling medium, wherein the chiller has a compression refrigerant circuit with a compressor (1), a condenser (2), an expansion valve (3) and an evaporator (4), wherein the evaporator (4) is a heat exchanger via which a refrigerant (6) of the compression refrigerant circuit is thermally coupled in a fluidically separated manner to a liquid cooling medium (7) to be cooled, wherein an outlet (8) of the heat exchanger (4) for cooled, liquid cooling medium (7) opens into at least one buffer storage (9) and the cooled, liquid cooling medium (7) from the buffer storage (9) is fed to a cooling medium outlet (11) of the chiller, wherein a PCM material (12) is accommodated in the buffer storage (9) and the cooled liquid cooling medium (7) in the buffer storage (9) is passed through a heat exchanger (13), via which the cooled, liquid cooling medium (7) is PCM material (12) is thermally coupled,and wherein the heat exchanger (13) in the buffer storage (9) is penetrated by a piping system (14, 15, 16) through which the cooling medium (7) is conducted, characterized in that the piping system (14, 15, 16) has a cooling medium supply line (19) on each of the opposite outer sides (18) of the heat exchanger (13), and the cooling medium supply lines (19) are each guided in a meandering manner via a first piping section (14, 15) of the piping system (14, 15, 16) from the outer sides (18) to a central core region (20) of the heat exchanger (13).

Description

The invention is based on a chiller for cooling a liquid cooling medium, wherein the chiller has a compression refrigerant circuit with a compressor, a condenser, an expansion valve and an evaporator. The evaporator is a heat exchanger, via which a refrigerant of the compression refrigerant circuit is thermally coupled in a fluidically separated manner to a liquid cooling medium to be cooled. An outlet of the heat exchanger for cooled, liquid cooling medium opens into a buffer store, wherein the cooled, liquid cooling medium is fed from the buffer store to a cooling medium outlet of the chiller. A PCM material is accommodated in the buffer store and the cooled liquid cooling medium in the buffer store is conducted through a heat exchanger via which the cooled liquid cooling medium is thermally coupled to the PCM material. The heat exchanger in the buffer store is traversed by a pipe system through which the cooling medium is conducted. Such a chiller is known from GB 2 327 751 A1. A similar chiller is also shown by DE 10 2010 043 245 A1 and DE 198 60 057 A1.DE 10 2012 112 646 A1 describes a cooling arrangement having a heat exchanger to which a heat transport fluid is supplied, heat being extracted from the heat transport fluid or being supplied to it by means of the heat exchanger. This heat is at least partially introduced into a heat exchanger or removed therefrom, wherein the heat exchanger is in heat-conducting contact with a heat accumulator. The heat accumulator comprises a phase change material ("PCM material") as heat-storing material.DE 10 2014 109 165 A1 discloses a latent heat storage device in which a phase change material is accommodated in a tubular encapsulation. The tubular enclosure is of double-walled design, wherein a liquid heat transport medium is passed through between the spaced-apart walls of the enclosure in order to exchange heat with the PCM material.WO 2015 / 028896 A1 describes a cooling arrangement which has a compression refrigeration circuit and, for redundancy purposes, an additional pump circuit which comprises heat sinks designed as PCM elements, so that cooling power can be temporarily provided with the aid of the PCM material in the event of failure of the compression refrigerant circuit.The chillers known from the prior art, in which cooled cooling medium is stored in a cooling medium tank or buffer store in order to reduce the clock frequency of the compression refrigerant circuit, have the disadvantage that they have a comparatively large structural volume on account of the required tank volume. The liquid cooling medium frequently used is water or oil, which, because of its given heat capacity, must be stored in a certain minimum volume in the tank in order to be able to achieve a reasonable reduction in the cycle rate of the compression refrigerant circuit. The external dimensions of the chillers known from the prior art are therefore not reducible to any desired extent.It is therefore the object of the invention to further develop a chiller of the type described at the beginning in such a way that it has dimensions that are as compact as possible.This object is achieved by a chiller having the features of claim 1. Claim 8 relates to a corresponding cooling arrangement and claim 9 relates to a corresponding switch cabinet arrangement. The dependent claims each relate to advantageous embodiments of the invention.Accordingly, it is provided that the pipeline system has a cooling medium lead in each case on opposite outer sides of the heat exchanger, and the cooling medium leads are guided in meandering fashion from the outer sides to a central core region of the heat exchanger via in each case a first pipeline section of the pipeline system.While, on the one hand, the common and in practice established cooling media, such as water or oil, can therefore still be used, the invention uses the higher heat capacity of PCM materials compared to these cooling media by providing a heat exchanger in the buffer store, which heat exchanger provides a heat exchange between the PCM material stored in the buffer store and the cooled, liquid cooling medium. Thus, while maintaining the known sizes of the buffer tank, the cycle rate of the compression refrigerant circuit can be lowered further, thereby preserving the active components of the compression refrigerant circuit and thus increasing the durability of the compression refrigerant circuit. Conversely, it is also possible, however, to reduce the volume of the buffer tank while maintaining the usual cycle rates of the compression refrigerant circuit and thus to reduce the external dimensions of the chiller.The heat exchanger can be, for example, a plate or plate heat exchanger with a pipe system through which the cooled, liquid cooling medium is conducted, wherein the PCM material surrounds the plate or plate heat exchanger in a thermally conductive manner.It is also conceivable to provide the PCM material as a plurality of PCM material capsules, each with a PCM material core which is completely surrounded by a double-walled tubular jacket through which the cooling medium flows. Such an encapsulated PCM material is known, for example, from DE 10 2014 109 165 A1. When the PCM material is provided as a plurality of PCM material capsules, the tube jackets of the plurality of PCM material capsules may be fluidically connected in series or in parallel.The heat exchanger in the buffer store can be a plate or plate heat exchanger with parallel spaced heat exchanger plates or plates, wherein the heat exchanger is penetrated by a piping system through which the cooling medium is conducted. The PCM material may be received in cavities between the vanes or plates and / or the vanes or plates may be hollow with PCM material enclosed between opposing walls.The two first pipe sections can each be led in meandering fashion over the central core region as far as the respective opposite outer side, wherein they are each connected via connecting lines to a second pipe section of the pipe system in the core region of the heat exchanger. In this case, the two first pipeline sections can bridge the core region by means of jump lines, so that they are not in thermal contact with PCM material arranged in the core region.The second pipeline section can have a central feed line into which the connecting lines open, wherein the second pipeline section, starting from the central feed line, is guided in meandering fashion in the direction of the opposite outer side.At opposite outer boundaries of the core region, an outlet of the second pipe section can be connected to a return of the heat exchanger via a respective further connecting line.A switchgear cabinet arrangement can have a chiller of the type described above and a switchgear cabinet housing with at least one module insert, in particular at least one 19" insert, wherein the buffer store is at least one insert housing which is inserted into one of the module inserts and can optionally be removed therefrom again and in which the heat exchanger and the PCM material (12) are accommodated.The at least one plug-in housing, in particular the heat exchanger ( 13), can fluidically contact a feed line and a return line for the cooled, liquid cooling medium in an plug-in position in which the plug-in housing is completely inserted into the assembly plug-in.The switchgear cabinet housing can have a plurality of module inserts arranged vertically one above the other and / or horizontally next to one another and a plurality of insert housings accommodated therein, wherein the module inserts each have a feed connection and a return connection for the insert housings, in particular the heat exchangers thereof, wherein the feed connections and the return connections are connected in series to one another via a respective piping system for the cooling medium.The pipe systems can be fastened to a mounting plate with the feed connections and the return connections, wherein the feed connections and the return connections are designed as quick-action couplings with an insertion direction oriented perpendicularly to the mounting plate and accordingly in the insertion direction of the insertion housings, and wherein the insertion housings have coupling counterparts complementary to the quick-action couplings on their end side facing the mounting plate in the insertion position.A first of the piping systems that connects the flow connections to one another can be fluidically connected to the outlet of the heat exchanger, wherein a second of the piping systems that connects the flow connections to one another is fluidically connected to the cooling medium outlet of the chiller.A cooling arrangement can have a chiller of the type described above and a cold consumer, for example a machine tool with a component to be cooled, wherein the cold consumer forms a cooling medium circuit with the heat exchanger, the buffer store and a pump for the cooling medium. The cooling medium can be thermally coupled to the refrigerant of the compression refrigerant circuit via the heat exchanger.An operating method for a chiller of the type described above may comprise the following steps:circulating the cooling medium between a cold consumer, the heat exchanger and the buffer store;activating the compression refrigerant circuit and cooling the PCM material until it has reached a lower set temperature or has substantially completely switched from a liquid to a solid state;disabling the compression refrigerant circuit upon reaching the set temperature or substantially full solid state state of the PCM material; andre-activating the compression refrigerant circuit when the PCM material has exceeded an upper limit temperature or is substantially completely in the liquid aggregate state.Further details of the invention are explained with reference to the following figures. The following shows: FIG. 1 shows a schematic illustration of a cooling arrangement with a chiller according to the prior art; FIG. 2 shows a schematic illustration of a cooling arrangement with a chiller according to one embodiment of the invention; FIG. 3 is a schematic cross-sectional view through a piping system of a heat exchanger according to an embodiment of the invention; FIG. 4 shows a heat exchanger using the piping system according to FIG. 3 according to an embodiment of the invention; FIG. 5 shows a schematic cross-sectional view through an insert housing of a switchgear cabinet arrangement; FIG. 6 shows a schematic view of an insert housing in a perspective illustration; FIG. 7 shows a schematic illustration of an arrangement of a plurality of assembly inserts arranged vertically one above the other; and FIG. 8 shows an exemplary switch cabinet housing of a switch cabinet arrangement.FIG. 1 shows an exemplary embodiment for a cooling arrangement using a chiller as is known from the prior art. The cooling arrangement has a compression refrigerant circuit which is thermally coupled in a fluidically separated manner via a heat exchanger 4 to a cooling medium circuit for cooling a cold consumer 100, for example a machine tool. All the components, except for the cold consumer 100, can be accommodated in a common housing of the chiller, wherein the housing, as is fundamentally known from the prior art, can have interfaces for the connection of a cooling medium supply line and a cooling medium return line for the cold consumer.The compression refrigerant circuit is essentially composed of a compressor 1, a condenser 2, an expansion valve 3 and an evaporator 4. The evaporator 4 is a heat exchanger in order to exchange thermal energy between the compression refrigerant circuit and the cooling medium circuit formed with the cold consumer 100, so that a heat exchange is provided between the refrigerant 6 and the cooling medium 7 via the heat exchanger 4 with simultaneous fluidic separation of the two circuits from one another.In order to reduce the cycle frequency of the compression refrigerant circuit, a buffer tank 9 is provided which holds a certain volume of the cooling medium 7, whereby the heat capacity of the cooling medium 7 added up over the total volume of the cooling medium 7 is correspondingly increased. A pump 10 is provided for the purpose of circulating the cooling medium 7 through the cold consumer 100, the heat exchanger 4 and the buffer store 9. It is understood that given a power loss of the cold consumer 100, the cycle frequency of the compression refrigerant circuit is directly proportional to the volume of the buffer tank 9 or cooling medium 7 contained therein. The larger the volume of the buffer reservoir 9, the larger the volume of the cooling medium 7 and, accordingly, the temperature of the cooling medium 7 rises more slowly given a power loss of the cold consumer 100.In a modification of the arrangement shown in FIG. 1 according to the prior art, in the arrangement according to an embodiment of the invention shown in FIG. 2, for further reducing the cycle rate of the compression refrigerant circuit with simultaneously compact construction dimensions, it is provided that a PCM material 12 is accommodated in the buffer store 9 and the cooled, liquid cooling medium in the buffer store 9 is conducted through a heat exchanger 13, via which the cooled, liquid cooling medium 7 is thermally coupled to the PCM material 12. In other words, the embodiment makes use of the increased heat capacity of PCM materials compared to conventional cooling media 7, such as oil or water, so that for given dimensions of the buffer store 9 the cycle rate of the compression refrigerant circuit can be substantially reduced or, if the design of the chiller is to be as compact as possible, the cycle rates known from the prior art can be maintained with a simultaneously reduced overall size of the buffer store 9 and thus of the chiller as a whole.The PCM material can occupy substantially the entire volume of the buffer tank 9 which is not occupied by the heat exchanger 13 itself, and in particular all the cavities 17 between the fins or plates of the heat exchanger 13 can be filled by the PCM material 12, so that the most effective heat exchange possible between the PCM material 12 and the heat exchanger 13, which can accordingly be configured as a fin or plate heat exchanger, is ensured.FIG. 3 shows the piping system 14, 15, 16 of a heat exchanger 13 (compare FIG. 2 ) according to an embodiment of the invention. In order to achieve an optimum heat distribution in the PCM material 12 and accordingly a cooling back effect which is as optimum as possible, it has been found that the pipeline system 14, 15, 16 which passes through the plate heat exchanger 13 should at least approximately have the line guide shown in FIG. 3. For this purpose, it can be provided that the pipeline system 14, 15, 16 has a cooling medium lead 19 on opposite outer sides 18 of the heat exchanger, wherein the cooling medium leads 19 are guided in meandering fashion from the respective outer side 18 to a central core region 20 of the heat exchanger 13 via a respective first pipeline section 14, 15 of the pipeline system 14, 15, 16.It can also be seen that the two first pipe sections 14, 15 are each guided in meandering fashion across the central core region 20 as far as the respective opposite outer side 18, where they are each connected via connecting lines 21 to a second pipe section 16 of the pipe system 14, 15, 16 in the core region 20 of the heat exchanger. In particular, the two first pipe sections 14, 15 each have jump pipes 27 which are guided in the outer region of the heat exchanger and bridge the core region 20, so that the first and the second pipe system 14, 15 are not in thermal contact with the PCM material in the core region 20 of the heat exchanger.The second pipeline section 16 has a central feed line 22, into which the connecting lines 21 open, wherein the second pipeline section 16 is guided in meandering fashion in the direction of the opposite outer side 18 starting from the central feed line 22. At opposite outer boundaries 23 of the core region 20, two outlets 24 of the second pipe section 16 are connected to a return 26 of the heat exchanger 13 via further connecting lines 25.In FIG. 4, an exemplary embodiment of a heat exchanger 13 using the piping system 14, 15, 16 according to FIG. 3 is shown in perspective view. The piping 14, 15, 16 includes a plurality of parallel fins 18 to improve heat exchange between the piping and the PCM material (not shown) surrounding the heat exchanger 13. In particular, the jump lines 27 can also be seen, which serve to ensure that the cooling medium 7 conducted through the pipeline system 14, 15, 16 is initially in thermal contact with the PCM material (not shown) in the outer region of the heat exchanger 13 before it leaves the pipeline system 14, 15, 16 in the core region 20 (cf. FIG. 3 ). This ensures that the already precooled cooling medium 7 finally flows through the core region of the PCM material and thus the PCM material remains in its solid aggregate state as long as possible in the core region of the heat exchanger 13 or in the middle of the buffer store and thus cools the outer, possibly already liquefied part.FIGS. 5 to 8 show, when viewed together, an embodiment of a switch cabinet arrangement within the meaning of the present invention. The components of the arrangement shown in the individual figures can, however, also be used independently of one another in other embodiments. Accordingly, as shown in FIGS. 5 and 6, a cartridge 202 may house a chiller heat exchanger 13 with the internal dimensions of the cartridge 202 being greater than the external dimensions of the chiller heat exchanger 13 such that the heat exchanger 13 may be completely housed in PCM material 12 embedded within the interior of the cartridge 202.The plug-in housing can have rails 212 on two opposite housing sides, which are perpendicular to an end side 210 of the plug-in housing 202, via which rails the plug-in housing 202 can be inserted into corresponding assembly inserts 201 in the interior of a switchgear cabinet housing. The assembly inserts 201 can be designed, for example, as 19-inch inserts. It is thus conceivable for a plurality of assembly inserts 201 to be formed vertically one above the other in the interior of a switchgear cabinet housing 200 in order to expand or reduce the buffer store of the chiller as required.On the end side 210 facing a mounting plate 209 or a backplane in an insertion position of the insertion housings 202, the insertion housing 202 has coupling counterparts 211 for a forward flow and a return flow of the heat exchanger 13 accommodated in the housing 202. When the plug-in housings 202 are inserted into the plugs 201 via the rails 212 on the opposite outer sides of the housing 202 and, for example, on opposite inner sides of the switch cabinet housing 200 or on a 19-inch rack accommodated in the switch cabinet housing 200, the plug-in housings 202 can be positioned with respect to feed connections 205 and return connections 206 arranged on the mounting plate 209 in such a way that, when an insertion position of the plug-in housings 202 is reached, the connections 205, 206 engage with the coupling counterparts 211 on the end side 210, so that a fluidic tight connection is produced between the respective plug-in housing 202 or the heat exchanger 13 accommodated therein and the feed 203 and the return 204. The flow line 203 is connected to the outlet 8 of the evaporator 4 (see FIG. 2 ), while the flow line 204 is connected to the cooling medium outlet 11 of the chiller or an interposed pump 10, corresponding to the arrangement in FIG. 2.The feed line 203 and the return line 204 are each designed as vertical pipe systems 207, 208, via which the feed line connections 205 and the return line connections 206 are connected to one another in series.The plug-in housings 202 can be hermetically sealed. For controlling the pump 10 or other regulating elements, for example the expansion valve, the plug-in housings 202 can have at least one temperature sensor. The coupling connections formed between the feed connections 205 or the return connections 206 and the coupling counterparts 211 can be formed in particular as drip-free quick-action couplings.The design shown in FIGS. 5 to 8 allows that if necessary also a plurality of the switchgear cabinet housings shown for example in FIG. 8 can be used next to one another and with piping systems 207, 208 connected in series or in parallel. This achieves a space-saving system in which, on the one hand, primary energy can be saved by using an ambient temperature which is lowered as a result of weathering, for example using free cooling, and, on the other hand, thermal load peaks are buffered. Electrical loads can thus also be temporarily displaced indirectly.The features of the invention disclosed in the above description, in the drawing and in the claims can be essential for the realization of the invention both individually and in any combination.List of reference characters1 Compressor 2 Condenser 3 Expansion valve 4 Evaporator 5 Fan 6 Refrigerant 7 Cooling medium 8 Outlet 9 Buffer store 10 Pump 11 Cooling medium outlet 12 PCM material 13 Heat exchanger 14, 15 First pipeline sections 16 Second pipeline section 17 Cavity 18 Outer side 19 Cooling medium lead 20 Core region 21 Connecting line 22 Feed line 23 Outer boundary 24 Outlet 25 Connecting line 26 Return 27 Power line 28 Slat 100 Cold consumer 200 Switchgear cabinet housing 201 Module insert 202 Insert housing 203 Lead 204 Return 205 Lead connection 206 Return connection 207 Pipe system of the lead 208 Pipe system of the return 209 Mounting plate 210 End side 211 Coupling counterpart 212 Rail

Claims

Chiller for cooling a liquid cooling medium, wherein the chiller has a compression refrigerant circuit having a compressor (1), a condenser (2), an expansion valve (3) and an evaporator (4), wherein the evaporator (4) is a heat exchanger via which a refrigerant (6) of the compression refrigerant circuit is thermally coupled in a fluidically separated manner to a liquid cooling medium (7) to be cooled, wherein an outlet (8) of the heat exchanger (4) for cooled liquid cooling medium (7) opens into at least one buffer store (9) and the cooled liquid cooling medium (7) from the buffer store (9) is fed to a cooling medium outlet (11) of the chiller, wherein a PCM material (12) is accommodated in the buffer store (9) and the cooled liquid cooling medium (7) is fed in the buffer store (9) through a heat exchanger (13) via which the cooled, liquid cooling medium (7) is fed in the buffer store (9), Liquid cooling medium (7) is thermally coupled to the PCM material (12), and wherein the heat exchanger (13) in the buffer store (9) is penetrated by a pipeline system (14, 15, 16) through which the cooling medium (7) is conducted, characterized in that the pipeline system (14, 15, 16) has a cooling medium lead (19) in each case on opposite outer sides (18) of the heat exchanger (13), and the cooling medium leads (19) are guided in meandering fashion from the outer sides (18) to a central core region (20) of the heat exchanger (13) via in each case a first pipeline section (14, 15) of the pipeline system (14, 15, 16).Chiller according to claim 1, wherein either - the heat exchanger (13) is a plate or plate heat exchanger with a pipe system through which the cooled, liquid cooling medium (7) is passed, wherein the PCM material (12) surrounds the plate or plate heat exchanger; or - wherein the PCM material (12) is provided as a plurality of PCM material capsules, each with a PCM material core which is completely surrounded by a double-walled tube jacket through which the cooling medium flows.The chiller of claim 2, wherein when the PCM material (12) is provided as a plurality of PCM material capsules, the tube jackets of the plurality of PCM material capsules are fluidly connected in series or in parallel.Chiller according to one of the preceding claims, in which the heat exchanger (13) in the buffer store (9) is a plate or plate heat exchanger with parallel spaced heat exchanger plates or plates, through which a pipe system (14, 15, 16) passes, through which the cooling medium (7) is conducted, wherein the PCM material (12) is accommodated in cavities (17) between the plates (28) or plates and / or the plates (28) or plates are formed hollow, with PCM material (12) enclosed between opposite walls.The chiller according to claim 1, wherein the two first pipe sections (14, 15) are each guided in meandering fashion across the central core region (20) as far as the respective opposite outer side (18), where they are each connected via connecting lines (21) to a second pipe section (16) of the pipe system (14, 15, 16) in the core region (20) of the heat exchanger (13), wherein the two first pipe sections (14, 15) preferably bridge the core region (20) by means of jump lines (27).The chiller according to claim 5, wherein the second pipe section (16) has a central feed line (22) into which the connecting lines (21) open, wherein the second pipe section (16), starting from the central feed line (22), is guided in meandering fashion in the direction of the opposite outer side (18).The chiller according to claim 6, wherein at opposite outer boundaries (23) of the core region (20) two exits (24) of the second pipe section (16) are connected via further connecting pipes (25) to a return (26) of the heat exchanger (13).Cooling arrangement having a chiller according to one of the preceding claims and a cold consumer (100) which forms a cooling medium circuit with the heat exchanger (4), the buffer store (9) and a pump (10) for the cooling medium (7), wherein the cooling medium (7) is thermally coupled to the refrigerant (6) of the compression refrigerant circuit via the heat exchanger (4).Switchgear cabinet arrangement, which comprises a chiller according to one of Claims 1 to 7 and a switchgear cabinet housing (200) having at least one module insert (201), in particular at least one 19" insert, wherein the buffer store (9) is at least one insert housing (202) which is inserted into one of the module inserts (201) and can optionally be removed therefrom again and in which the heat exchanger (13) and the PCM material (12) are accommodated.Switchgear cabinet arrangement according to claim 9, in which the at least one plug-in housing (202), in particular the heat exchanger (13), in a plug-in position, in which the plug-in housing (202) is completely inserted into the assembly plug-in (201), makes fluidic contact with a feed line (203) and a return line (204) for the cooled, liquid cooling medium (7).Switchgear cabinet arrangement according to claim 9 or 10, in which the switchgear cabinet housing (200) has a plurality of modular inserts (201) arranged vertically one above the other and / or horizontally next to one another and a plurality of insertable housings (202) accommodated therein, wherein the modular inserts (201) each have a feed connection (205) and a return connection (206) for the insertable housings (202), in particular the heat exchangers (13) thereof, wherein the feed connections (205) and the return connections (206) are connected in series to one another via a respective piping system (207, 208) for the cooling medium (7).Switchgear cabinet arrangement according to Claim 11, in which the pipe systems (207, 208) with the feed connections (205) and the return connections (206) are fastened on a mounting plate (209), wherein the feed connections (205) and the return connections (206) are designed as quick-action couplings with an insertion direction oriented perpendicularly to the mounting plate (209) and accordingly in the insertion direction of the insertion housings (202), and wherein the insertion housings (202) have, on their end side (210) facing the mounting plate (209) in the insertion position, coupling counterparts (211) which are complementary to the quick-action couplings.Switchgear cabinet arrangement according to claim 11 or 12, wherein a first of the piping systems (207, 208) connecting the flow connections (205) to one another is fluidically connected to the outlet (8) of the heat exchanger (4), and wherein a second of the piping systems (207, 208) connecting the return connections (206) to one another is fluidically connected to the cooling medium outlet (11) of the chiller.

Images