Abstract
The invention relates to a heat exchanger assembly with at least one multi-pass heat exchanger, comprising a first distributor (1) with a first connection part (1a) for connecting to a fluid line (9), a second distributor (2) with a second connection part (2a) for connecting to a fluid line (9), and at least one first deflection distributor (4), as well as a plurality of tube lines (5) through which a fluid, in particular water, can flow, wherein the first distributor (1) and the second distributor (2) are arranged at one end (A) of the heat exchanger assembly, the deflection distributor (4) is arranged at the opposite end (B) and the tube lines (5) extend from the one end (A) to the opposite end (B), and wherein the first connection part (1a) is arranged at a lowest point (T) or at least near to the lowest point (T) of the first distributor (1) and the second connection piece (2a) is arranged at a lowest point (T) or at least near to the lowest point (T) of the second distributor (2). In order to allow for the heat exchanger assembly to be quickly filled with the fluid and quickly emptied, a third connection part (3) is arranged on the first distributor (1) and/or on the second distributor (2) at a highest point (H) or at least near to the highest point (H) of the respective distributor (1 or 2), and at least one ventilation opening (10) is provided at a highest point (T) or at least near to the highest point (T) of the deflection distributor (4) for pressure equalisation with the environment.
Claims
1. Heat exchanger assembly having at least one multi-pass heat exchanger, which comprises a first distributor having a first connection piece for connecting to a fluid line, a second distributor having a second connection piece for connecting to a fluid line, and at least one first deflection distributor, as well as a plurality of pipelines through which a fluid can flow, wherein the first distributor and the second distributor are arranged at one end of the heat exchanger assembly and the deflection distributor is arranged at an opposite end thereof, and the pipelines extend from the one end to the opposite end, and wherein the first connection piece is arranged at a lowest point or at least near the lowest point (of the first distributor and the second connection piece is arranged at a lowest point or at least near the lowest point of the second distributor, wherein a third connection piece is arranged on the first distributor and/or on the second distributor at a highest point or at least near the highest point thereof and at least one vent opening for pressure equalization with the environment is arranged at a highest point or at least near the-highest point of the deflection distributor.
2. Heat exchanger assembly according to claim 1, wherein a first group of the plurality of pipelines are formed as supply lines and are connected to the first distributor and to the deflection distributor, and a second group of the plurality of pipelines are formed as recirculating lines and are connected to the second distributor and to the deflection distributor.
3. Heat exchanger assembly according to claim 1, wherein the first distributor, the second distributor and the deflection distributor are each formed as a tubular manifold arranged such that a longitudinal axis thereof is vertical or oblique to a vertical axis thereof.
4. Heat exchanger assembly according to claim 1, wherein the first distributor and the second distributor are arranged at a face end of the heat exchanger assembly, and wherein the deflection distributor arranged at an opposite face of the heat exchanger assembly.
5. Heat exchanger assembly according to claim 1, wherein a controllable valve is arranged in the first connection piece and/or in the second connection piece.
6. Heat exchanger assembly according to claim 1, wherein the heat exchanger has an external inflow surface which can be flowed against by a gas stream, and wherein the distributor which faces the inflow surface, contains the third connection piece.
7. Heat exchanger assembly according to claim 1, wherein the plurality of pipelines are parallel to each other and obliquely to the horizontal, wherein an angle which the pipelines define with the horizontal is between 0.5° and 5°.
8. Heat exchanger assembly according to claim 1, wherein in an emptying mode the fluid flows by gravity from each of the plurality of pipelines into one or more of the first distributor and the second distributor, and in that in a tilling mode the fluid flows against gravity from the first distributor and the second distributor into one or more of the plurality of pipelines.
9. Heat exchanger assembly according to claim 2, wherein in a recooling mode the fluid flows into the supply lines through the first connection piece and flows out of the recirculating lines through the third connection piece.
10. Heat exchanger assembly according to claim 8, wherein in emptying mode the fluid flows out by gravity via the first connection piece of the first distributor and the second connection piece of the second distributor into a lower fluid line which is connected to the first and second connection pieces.
11. Heat exchanger assembly according to any preceding claim, characterized by a plurality of sensors for detecting ambient parameters, in particular outside temperature and/or wind speed.
12. Heat exchanger assembly according to claim 1, wherein at least a part of the plurality of pipelines is adapted to be cranked towards the deflection distributor at its end facing the deflection distributor.
13. Heat exchanger assembly according to claim 12, wherein the deflection distributor (4) is tubular in form and is arranged such that its longitudinal axis is inclined to the vertical, preferably by an angle in the range of 15° to 70° and in particular by an angle in the range of 15° to 45°.
14. Heat exchanger assembly according to claim 1, wherein the heat exchanger assembly comprises two heat exchangers arranged opposite each other, each of which is inclined to the vertical and arranged in a V-shape relative to one another.
15. Heat exchanger assembly according to any preceding claim, wherein the fluid passes through the pipelines (5) of each heat exchanger twice or four times.
16. Heat exchanger assembly according to claim 1, further comprising a second deflection distributor and a third deflection distributor, wherein one of the deflection distributors is arranged at the end of the heat exchanger where the first and second distributors are located.
17. Heat exchanger assembly according to claim 1, further comprising a valve having a predetermined maximum flow cross-section for the passage of air arranged in the vent opening, wherein the valve can he opened and closed and, when the valve is fully opened, a maximum flow cross-section for the passage of air is released and the valve closes automatically when the fluid enters the valve.
18. Heat exchanger assembly according to any preceding claim, characterized by a control device for controlling the heat exchanger assembly, wherein the heat exchanger assembly can be operated in a recooling mode, an emptying mode or a filling mode via the control device as a function of ambient parameters, in particular outside temperature and/or wind speed.
19. Cooling system comprising a circuit in which water is conducted as a heat transfer medium, a tank which is connected to the circuit and in which the water is stored, a heat source which supplies heat to the fluid at the location of the heat source, and a recooler in which the water is cooled by heat exchange with the ambient air, wherein the recooler contains at least one heat exchanger assembly according to claim 1,
20. Method for operating a heat exchanger assembly having at least one heat exchanger, which comprises a first distributor (1) having a first connection piece (1a) for connecting to a fluid line (9), a second distributor (2) having a second connection piece (2a) for connecting to a fluid line (9), and at least one first deflection distributor (4), as well as a plurality of pipelines (5) through which a fluid, in particular water, can flow, wherein the first distributor (1) and the second distributor (2) are arranged at one end (A) of the heat exchanger assembly and the deflection distributor (4) is arranged at the opposite end (B) and the pipelines (5) extend from the one end (A) to the opposite end (B) and wherein the first connection piece (1a) is arranged at a lowest point (T) or at least near the lowest point (T) of the first distributor (1) and the second connection piece (2a) is arranged at a lowest point (1) or at least near the lowest point (T) of the second distributor (2), and the heat exchanger assembly, depending on ambient parameters, in particular the outside temperature, is alternately operated in different operating modes, comprising a recooling mode, an emptying mode, a filling mode and a standby mode, characterized in that in the emptying mode the fluid flows by gravity out of all of the pipelines (5) into the first distributor (1) and the second distributor (2) and from there in each case via the first and the second connection piece (1a, 2a) into a fluid line (9), and in that in the filling mode the fluid flows against gravity Out of the first distributor (1) and the second. distributor (2) into all of the pipelines (5).
21. Method according to claim 20, characterized in that on the first distributor (1) and/or on the second distributor (2) a third connection piece (3) is arranged at a highest point (H) or at least near the highest point (H) of the respective distributor (1 or 2), and in that at least one vent opening (10) is arranged at a highest point (T) or at least near the highest point (T) of the deflection distributor (4) for pressure equalization with the environment, wherein
22. Method according to claim 21, characterized in that the fluid in the recooling mode is introduced into the heat exchanger assembly via the first connection piece (la) at the lowest point (T) or at least near the lowest point (T) of the first distributor (I) and is discharged via the third connection piece (3) at the highest point (H) or at least near the highest point (H) of the second distributor (2),
23. Method according to any of claims 20 to 22, characterized in that the heat exchanger assembly is operated in standby after the emptying mode, in which the pipelines (5) are at least substantially empty.
24. Method according to any of claims 20 to 23, characterized in that the switching of the operating modes of the heat exchanger assembly is performed by actuation, in particular opening and closing, of valves of the heat exchanger assembly.
25. Method according to claim 24, characterized in that the switching of the operating modes is perforated by electrically controlling the valves.
26. Method according to any of claims 20 to 25, characterized in that ambient parameters, in particular outside temperature (T.sub.U) and/or wind speed (v), as well as the inlet temperature (T.sub.in) of the fluid on entering the heat exchanger assembly are detected by means of sensors and transferred as measured values to a control device, and in that the control device calculates an outlet temperature (T.sub.out) of the fluid as it exits the heat exchanger assembly based on the detected measured values.
27. Method according to claim 26, characterized in that the control device operates the heat exchanger assembly in recooling mode as long as the calculated outlet temperature (T.sub.min) is greater than or equal to a predetermined limit value (T.sub.min) and switches the heat exchanger assembly to emptying mode when the calculated outlet temperature (T.sub.out) is below the limit value (T.sub.min).
28. Method according to any of claim 26 or 27, characterized in that the control device switches the heat exchanger assembly from standby to filling mode as soon as the calculated outlet temperature (T.sub.out) is greater than or equal to a predetermined limit value (T.sub.min).
29. Method according to any of claims 26 to 28, characterized in that the predetermined limit value (T.sub.min) is greater than 0° C. and is preferably in the range of 1° C. to 7° C.
30. Method according to any of claims 26 to 29, characterized in that the predefined limit value (T.sub.min) is determined as a function of the thermal capacity of the heat exchanger assembly and in particular as a function of the dimensioning, the number of passes of the fluid through the pipelines the fluid used and the volume flow rate of the fluid through the pipelines.
31. Method according to one of the methods according to any of claims 26 to 30, characterized in that the heat exchanger assembly comprises a plurality of heat exchangers which are each controlled by the control device and can be operated independently of one another in the various operating modes, wherein the control device controls the number of heat exchangers operated in recooling mode as a function of the detected ambient parameters and; the detected inlet temperature (T.sub.in) of the fluid.
32. Method according to claim 31, characterized in that the fluid volume conducted through the heat exchanger assembly per unit of time remains the same regardless of the number of heat exchangers operated in. recooling mode.
Description
[0026] These and other features and advantages of the invention will be apparent from the exemplary embodiment described in more detail below with reference to the accompanying drawings. In the drawings:
[0027] FIG. 1: is a representation of a first exemplary embodiment of a heat exchanger assembly according to the invention having two 4-pass heat exchangers arranged in a V-shape relative to one another, in a view of a front face of the heat exchanger assembly;
[0028] FIG. 2: is a side view of the 4-pass heat exchanger assembly of FIG. 1;
[0029] FIG. 3: is a schematic representation of various operating modes of the heat exchanger assembly of FIGS. 1 and 2, where FIG. 3a shows a recooling mode, FIG. 3b shows a filling mode, and FIG. 3c shows an emptying mode of a multi-pass heat exchanger of the heat exchanger assembly;
[0030] FIG. 4: is a representation of a second exemplary embodiment of a heat exchanger assembly according to the invention having two 2-pass heat exchangers arranged in a V-shape relative to one another, in a view of a front face of the heat exchanger assembly;
[0031] FIG. 5: is a view towards the rear face of the 2-pass heat exchanger assembly of FIG. 4;
[0032] FIG. 6: is an overview of the second exemplary embodiment of a heat exchanger assembly according to the invention having two 2-pass heat exchangers arranged in a V-shape relative to one another in a view of the front face of the heat exchanger assembly (FIG. 6a), of the rear face of the 2-pass heat exchanger assembly (FIG. 6b) and in a side view (FIG. 6c);
[0033] FIG. 7: is a schematic representation of different operating modes of the 2-pass heat exchanger assembly of FIG. 6, where FIG. 7a shows a recooling mode, FIG. 7b shows a filling mode and FIG. 7c shows an emptying mode of the 2-pass heat exchanger;
[0034] FIG. 8: shows representations of the various operating modes of the 2-pass heat exchanger assembly of FIG. 7 by means of sectional drawings of the 2-pass heat exchanger through a horizontal plane, where FIG. 7a shows the recooling mode, FIG. 7b shows the filling mode, and FIG. 7c shows the emptying mode of the 2-pass heat exchanger;
[0035] FIG. 9: is a schematic representation of a cooling system containing a heat exchanger assembly according to the invention having two opposite 2-pass heat exchangers, where FIG. 9a shows the entire cooling system and the heat exchanger assembly used therein both in a view of the front face and in a side view and FIG. 9b shows a detailed view from FIG. 9a in the area of the heat exchanger assembly;
[0036] FIG. 10: is a schematic representation of different operating modes of the heat exchanger assembly of the cooling system of FIG. 9, where FIG. 10a shows the heat exchanger assembly in recooling mode, FIG. 10b shows the heat exchanger assembly in emptying mode, and FIG. 10c shows the heat exchanger assembly in filling mode;
[0037] FIG. 11: is a schematic representation of another exemplary embodiment of a cooling system having a combination of two heat exchanger assemblies according to the invention;
[0038] FIG. 12: is a schematic representation of possible operating modes of the combination of heat exchanger assemblies from FIG. 11.
[0039] FIGS. 1 and 2 show an exemplary embodiment of a heat exchanger assembly according to the invention, which can be used as a recooler R for cooling a fluid used as a heat transfer medium in a cooling system. In particular, water can be used as the heat transfer medium. In the following, the term water refers to the fluid used as the heat transfer medium, wherein another fluid can also be used as the heat transfer medium instead of water.
[0040] The heat exchanger assembly shown in FIGS. 1 and 2 includes two four-pass heat exchangers, which contain opposing planar heat exchangers extending obliquely to the vertical. As can be seen from the view of FIG. 1, the two heat exchangers are arranged in a V-shape relative to one another. The structure of the heat exchanger arranged on the right-hand side of FIG. 1 is explained below. The opposite heat exchanger arranged on the left-hand side of the heat exchanger assembly is constructed similarly. The two heat exchangers are attached to a housing 21 of the heat exchanger assembly. Each heat exchanger comprises a first distributor 1, formed as an inlet distributor, a second distributor 2, formed as an outlet distributor, as well as a first deflection distributor 4, a second deflection distributor 6 and a third deflection distributor 8, and a plurality of pipelines 5. The first distributor 1, the second distributor 2 and the third deflection distributor 8 are arranged at the front face end A of the heat exchanger assembly. The first and second deflection distributors 4, 6 are each arranged at the opposite end B of the heat exchanger assembly, i.e., at the rear face. The pipelines 5 extend in a longitudinal direction L of the heat exchanger assembly from one end A to the opposite end B. The pipelines 5 are thereby divided into a first group of pipelines 5a and a second group of pipelines 5b, wherein the first group of pipelines 5a serve as supply lines and the second group of pipelines 5b serve as recirculating lines. Some of the pipelines 5 of the first group of pipelines 5a (supply lines) connect the first distributor 1 (inlet distributor) to the first deflection distributor 4, and some of the pipelines 5 of the second group of pipelines 5b (return lines) connect the first deflection distributor 4 to the third deflection distributor 8. Some of the pipelines of the first group of pipelines 5a (supply lines) in turn connect the third deflection distributor 8 to the second deflection distributor 6, and some of the pipelines of the second group of pipelines 5b (return lines) in turn connect the second deflection distributor 6 to the second distributor 2 (outlet distributor), as shown in FIG. 3. The pipelines 5 of the supply and recirculating lines run at least essentially parallel to each other and are slightly inclined to the horizontal, as can be seen in FIG. 2. The inclination angle of the pipelines 5 to the horizontal is preferably between 0.5° and 5°, particularly preferably between 2′ and 4°, and in a preferred exemplary embodiment the angle between the pipelines and the horizontal plane is 3°.
[0041] A first connection piece 1a is arranged on the first distributor 1 (inlet distributor) at a lowest point T of this distributor 1. A second connection piece 2a is also arranged at a corresponding location, i.e., at a lowest point T, on the second distributor 2 (outlet distributor). On the second distributor 2 (outlet distributor), an additional connection piece, referred to as the third connection piece 3, is arranged at a highest point H. A connection piece 7, which is referred to as the fourth connection piece, is likewise arranged at the lowest point T of the third deflection distributor 8.
[0042] The deflection distributors (first and second deflection distributors 4, 6) arranged at the opposite end B of the heat exchanger assembly each have a vent opening 10 at a highest point H, as shown in FIG. 2. The vent opening 10 is conveniently arranged at the upper end of the deflection distributors 4, 6, which are formed as tubular manifolds. The opposite lower end of the tubular deflection distributors 4, 6 is closed. Conveniently, a valve 11 is arranged in each vent opening 10, with which the vent opening 10 can be opened or closed. However, the use of a valve in the vent openings 10 can also be omitted.
[0043] A controllable valve V for opening and closing each connection piece 3, 7 is inserted at least in the second connection piece 2a, which is arranged at the lower end of the second distributor 2 (outlet distributor), and in the fourth connection piece 7, which is arranged at the lower end of the third deflection distributor 8 (FIG. 2). The respective valve V can alternatively be placed at another location, e.g., in a fluid line connected to the respective connection piece 3, 7. The valves V can be controlled independently of one another in order to open or close the (lower) connection pieces 3 and 7 independently of one another.
[0044] FIG. 3 schematically shows different operating modes of the heat exchanger assembly. In the retooling mode shown in FIG. 3a, for example, water is conducted through the pipelines 5 (supply lines 5a and recirculating lines 5b) of the heat exchanger assembly as the heat transfer medium. At the same time, (cold) ambient air is sucked in from the environment by at least one fan 12 arranged on the upper side of the heat exchanger assembly, as shown in FIGS. 1 and 2, and conducted through the heat exchangers of the heat exchanger assembly to perform a heat exchange between the heat transfer medium (water) conducted through the pipelines 5 and the drawn-in air. To increase the heat transfer efficiency, fins 22 are attached to the pipelines 5 (FIG. 3) in order to increase the effective heat transfer area. In the exemplary embodiment shown, accordingly the heat exchangers are finned tube or fin-tube heat exchangers. Instead of conventional finned tube or fin-tube heat exchangers, micro-channel heat exchangers may also be used in the heat exchanger assembly according to the invention.
[0045] In the recooling mode shown schematically in FIG. 3a, the fluid used as the heat transfer medium is introduced via the first connection piece 1a into the first distributor 1 (inlet distributor) and from there is conducted through a part of the pipelines 5 of the first group of pipelines 5a (supply lines) to the first deflection distributor 4 and deflected therein into a part of the pipelines of the second group of pipelines 5a (return lines). The fluid flows through the recirculating lines to the third deflection distributor 8, where it is deflected again into part of the pipelines 5 of the first group of pipelines 5a (supply lines). The fluid flows in the supply lines to the second deflection distributor 6 and is deflected therein again into a part of the pipelines of the second group of pipelines 5a (recirculating lines) and finally flows into the second distributor 2 (outlet distributor). The fluid is withdrawn by the outlet distributor 2 through the third connection piece 3 arranged at the top end of the outlet distributor 2 and directed as a cooling medium into a cooling-medium reservoir (tank B) or directly to a consumer to be cooled, via a fluid line 9 connected to the third connection piece 3.
[0046] In the recooling mode according to FIG. 3a, the connection pieces 2a, 7 (second and fourth connection pieces) are dosed by the respective valve V arranged therein.
[0047] FIG. 3b is a schematic view of the heat exchanger assembly in a filling mode, in which the heat exchangers can either be filled for the first time or can be refilled with the fluid after emptying. In filling mode, the lower connection pieces 2a and 7 (second and fourth connection pieces), which are arranged at the lower end of the second distributor 2 and of the third deflection distributor 8, respectively, are open. As a result, the fluid can be simultaneously filled into the first and second distributors 1, 2 and the third deflection distributor 8 via the connection pieces 1a, 2a and 7 arranged at the lower end of each of the two distributors 1, 2 and the third deflection distributor 8. The fluid subsequently flows, as shown in FIG. 3b, simultaneously through all of the pipelines 5 (i.e., through both the supply lines 5a and the recirculating lines 5b) in the same direction of flow from the one end A of the heat exchanger assembly to the opposite end B. Due to the inclination of the pipelines 5 towards the front end A, the fluid in the pipelines 5 thereby flows upwards against gravity in the direction of the deflection distributors 4, 6 arranged at the rear face end B. The air present in the first and second deflection distributors 4, 6 is forced out through the vent openings 10 at the upper end of these two deflection distributors 4, 6, whereby the two deflection distributors 4, 6 are vented. In order to prevent the fluid from escaping from the vent openings 10 when the heat exchangers are completely filled with the filled fluid, a self closing valve 11 is conveniently arranged in the vent openings 10. The valve 11 automatically closes the vent opening 10 as soon as an internal pressure arises in the valve due to the incoming fluid.
[0048] To determine when the heat exchanger assembly is completely filled with fluid, the hydrostatic pressure of the fluid in the heat exchanger assembly is detected by means of a pressure sensor (P). Once the hydrostatic pressure detected by the pressure sensor (F) exceeds a predetermined pressure limit value, the heat exchanger assembly is switched from filling mode to recooling mode. Alternatively, the control device S of the heat exchanger assembly can also calculate an expected filling time from the parameters of said assembly, and the filling mode can be terminated as soon as the calculated filling time has elapsed while filling the heat exchanger assembly with the fluid.
[0049] Conversely, analogously to the filling of the heat exchanger assembly with the fluid, the heat exchanger assembly can also be rapidly emptied by opening the valves V in or on the second connection piece 2a and on the fourth connection piece 7. FIG. 3c shows an emptying mode of the heat exchanger assembly in which, with open valves V in the second connection piece 2a and the fourth connection piece 7, the fluid can flow simultaneously from all of the pipelines 5 (i.e., from both the supply lines 5a and the recirculating lines 5b) by gravity and in the same flow direction along the incline of the pipelines 5 from the rear end B to the front end A into the first and second distributors 1, 2 and into the third deflection distributor 8. The flow of the fluid is thereby facilitated on the one hand by the inclination of the pipelines 5 towards the front end A and on the other hand by a ventilation of the first and the second deflection distributors 4, 6 via the vent openings 10. For the ventilation of the first and the second deflection distributors 4, 6, the valve 11 in the vent openings 10 is opened so that ambient air can flow through the vent openings 10 into the deflection distributors 4, 6. Finally, the fluid can flow out through the lower connection pieces 1a, 2a and 7(first, second and third connection pieces) into a fluid line (not shown here) connected to said connection pieces 1a, 2a and 7.
[0050] The design of the heat exchangers according to the invention allows both rapid filling with the fluid and (in the event of risk of frost) rapid emptying of the heat exchanger assembly, due to the fluid being able to flow in and out through all of the pipelines 5 of the heat exchanger assembly simultaneously and in the same flow direction during both filling and outflowing.
[0051] FIGS. 4 and 5 show another exemplary embodiment of a heat exchanger assembly according to the invention, wherein the represented heat exchanger assembly contains two 2-pass heat exchangers which are arranged in a V-shape opposite each other and are inclined obliquely to the vertical. The inclination of the heat exchangers with respect to the vertical plane is conveniently in an angular range from 15° to 70° and preferably from 30° to 45°.
[0052] The structure of the heat exchanger arranged on the right-hand side of FIG. 4 is explained below. The opposite heat exchanger arranged on the left-hand side of the heat exchanger assembly is constructed similarly. The two 2-pass heat exchangers each comprise a first distributor 1, which is formed as an inlet distributor, a second distributor 2, which is formed as an outlet distributor, and a (single) first deflection distributor 4, and a plurality of pipelines 5. The first distributor 1 and the second distributor 2 are thereby arranged at the front face end A of the heat exchanger assembly. The deflection distributor 4 is arranged at the opposite end B of the heat exchanger assembly, i.e., at the rear face. The pipelines 5 extend in a longitudinal direction L of the heat exchanger assembly from one end A to the opposite end B. The pipelines 5 are thereby divided into a first group of pipelines 5a and a second group of pipelines 5b, wherein the first group of pipelines 5a serve as supply lines and the second group of pipelines 5b serve as recirculating lines. The pipelines 5 of the first group of pipelines 5a (supply lines) connect the first distributor 1 (inlet distributor) with the deflection distributor 4, the pipelines 5 of the second group of pipelines 5b (recirculating lines) connect the deflection distributor 4 with the second distributor 2 (outlet distributor), as shown in FIG. 4. The pipelines 5 of the supply and recirculating lines run at least partially parallel to one another and are slightly inclined to the horizontal, as can be seen in FIG. 6c. The angle of inclination of the pipelines 5 to the horizontal is again preferably between 0.5° and 5°, particularly preferably between 2° and 4°, and in a preferred exemplary embodiment the angle between the pipelines and the horizontal plane is 3°.
[0053] A first connection piece 1a is arranged on the first distributor 1 (inlet distributor) at a lowest point T of this distributor 1. A second connection piece 2a is also arranged at a corresponding location, i.e., at a lowest point T, on the second distributor 2 (outlet distributor). On the second distributor 2 (outlet distributor), an additional connection piece, referred to as the third connection piece 3, is arranged at a highest point H. The deflection distributor 4 arranged at the opposite end B of the heat exchanger assembly has a vent opening 10 at a highest point H, into which a valve 11 is inserted, as shown in FIG. 5. The vent opening 10 can be opened or closed via this valve 11, wherein the valve 11 is conveniently formed as a self closing valve which closes automatically as soon as a fluid enters the valve. A manually operated inspection valve 26 is provided below the valve 11, with which the upper end of the deflection distributor can be closed for inspection and maintenance work.
[0054] At least in the second connection piece 2a, which is arranged at the lower end of the second distributor 2 (outlet distributor), a controllable valve V (not shown here) is inserted for opening and closing the second connection piece 2a. Alternatively, the valve V can also be placed at another location, e.g., in a fluid line connected to the second connection piece 2a.
[0055] In FIG. 6, an overview of the second exemplary embodiment of the heat exchanger assembly according to the invention schematically shows the front face of the 2-pass heat exchanger assembly (FIG. 6a), the rear face (FIG. 6b) and a side view (FIG. 6c), FIG. 6 shows in particular the placement of the connection pieces 1a, 2a and 3 on the first and second distributors 1, 2 as well as the inclination of the pipelines 5 towards the front end A.
[0056] In FIGS. 7 and 8, different operating modes of the second exemplary embodiment of the heat exchanger assembly according to the invention (like FIGS. 4 to 6) are schematically shown. In the recooling mode shown in FIGS. 7a and 8a, water is conducted through the pipelines 5 (supply lines 5a and recirculating lines 5b) of the heat exchanger assembly as the heat transfer medium. At the same time, cold air is sucked in from the environment by at least one fan 12 arranged on the upper side of the heat exchanger assembly (as shown in FIG. 6c) and conducted through the heat exchangers of the heat exchanger assembly to perform a heat exchange between the heat transfer medium (water) conducted through the pipelines 5 and the drawn-in air. To increase heat transfer efficiency, fins 22 are in turn attached to the pipelines 5 (FIG. 8) in order to increase the effective heat transfer area. Instead of conventional finned or fin-tube heat exchangers, micro-channel heat exchangers may also be used in this exemplary embodiment of the heat exchanger assembly according to the invention.
[0057] In the recooling mode shown in FIGS. 7a and 8a, the fluid used as the heat transfer medium is introduced into the first distributor 1 (inlet distributor) via the first connection piece 1 a and is conducted from there through the pipelines 5 of the first group of pipelines 5a (supply lines) to the deflection distributor 4 and deflected therein into the pipelines of the second group of pipelines 5a (recirculating lines). The fluid flows through the recirculating lines back into the second distributor 2 (outlet distributor). The fluid is withdrawn from the outlet distributor 2 through the third connection piece 3 arranged at the top end of the outlet distributor 2 and directed as a cooling medium into a cooling-medium reservoir (tank B) or directly to a consumer to be cooled, via a fluid line connected to the third connection piece 3.
[0058] In the recooling mode according to FIGS. 7a and 8a, the second connection piece 2a is closed by the valve V arranged therein.
[0059] In FIGS. 7b and 8b, the heat exchanger assembly is shown in each case in a filling mode, in which the heat exchanger can either be filled for the first time or can be refilled with the fluid after emptying. In filling mode, the lower connection pieces 1a, 2a (first and second connection pieces), which are arranged at the lower end of the first and second distributors 2, respectively, are open. As a result, the fluid can be simultaneously filled into the first and second distributors 1, 2 via the lower connection pieces 1a, 2a. The fluid then flows, as shown in FIGS. 7b and 8b, simultaneously through all of the pipelines 5 (i.e., through both the supply lines 5a and the recirculating lines 5b) in the same direction of flow from the one end A of the heat exchanger assembly to the opposite end B. Due to the inclination of the pipelines 5 towards the front end A, the fluid in the pipelines 5 thereby flows upwards against gravity in the direction of the deflection distributor 4 arranged at the rear face end B. The air present in the deflection distributor 4 is forced out through the vent openings 10 at the upper end of the deflection distributor, whereby the deflection distributor 4 is vented. In order to prevent the fluid from escaping from the vent opening on the deflection distributor 4 when the heat exchangers are completely filled with the filled fluid, a self closing valve 11 is conveniently arranged in the vent opening 10.
[0060] Conversely, analogously to the filling of the heat exchanger assembly with the fluid, the heat exchanger assembly can also be rapidly emptied by opening the valve V in or on the second connection piece 2a. FIGS. 7c and 8c each show an emptying mode of the heat exchanger assembly in which, with open valve V in the second connection piece 2a, the fluid can flow simultaneously from all of the pipelines 5 (i.e., from both the supply lines 5a and the recirculating lines 5b) by gravity and in the same flow direction along the incline of the pipelines 5 from the rear end B to the front end A into the first and second distributors 1, 2. In this case, the flow of the fluid is again facilitated by the inclination of the pipelines 5 towards the front end A and by the ventilation of the deflection distributor 4 via the vent opening 10. Finally, the fluid can flow out through the lower connection pieces 1a, 2a (first and second connection pieces) into a fluid line (not shown here) connected to said connection pieces 1a, 2a.
[0061] By way of example, FIG. 9 shows a cooling system in which a heat exchanger assembly according to the invention may be used. The cooling system shown schematically in FIG. 9 comprises a circuit K in which a fluid, in particular water, is conducted as a heat transfer medium, a tank B which is connected to the circuit K and in which the fluid is stored, a heat source Q which supplies heat to the fluid at the location of the heat source, and at least one heat exchanger assembly according to the invention which is used in the cooling system as a recooler R in order to cool the fluid by heat exchange with the ambient air. In the example shown in FIG. 9, the heat exchanger assembly having two 2-pass heat exchangers as shown in FIGS. 4 to 6 is used as the recooler R.
[0062] In the process, the recooler R of the cooling system shown in FIG. 9 is connected to the tank B via fluid lines 9. The tank B is preferably open to the surroundings of the tank location. A fluid line 19 leads from the tank B to the heat source Q in order to supply the cooled fluid stored in tank B as the cooling medium to the heat source Q. A first pump P1 is provided for delivering the fluid from the tank B to the heat source Q. At the location of the heat source Q, the fluid is heated by heat exchange and fed back to the recooler R through another line 29. Conveniently, a second pump P2 is arranged in the line 29, which delivers the fluid from the heat source Q back to the recooler R. A branch line 30 branches off from the line 29 into the tank B. A valve V4 is provided for opening and closing the branch line 30. Another valve V3 is arranged downstream of the branch line 30 in the line 29. The line 29 branches at a branch point Z into a recirculating line 31 to the tank B and into a feed line 32 leading to the recooler R. Another valve V2 is arranged in the recirculating line 31 for opening and closing this line. The feed line 32 branches into a central feed line and two secondary lines, in each of which a three-way valve V1 is arranged. The central feed line branches again into two branches, wherein a first branch is in connection with the first connection piece 1a of the left heat exchanger and a second branch is in connection with the first connection piece 1a of the right heat exchanger. The secondary lines lead to the second connection piece 2a of the left and right heat exchanger, as can be seen in FIG. 9b. The feed line 32 is thus connected to the lower connection pieces 1a and 2a of the heat exchanger assembly via the three-way valves V1. A discharge line 33 is connected to the (upper) third connection piece 3 of the heat exchanger assembly, which leads to line 9 and is connected to it.
[0063] FIG. 10 shows various operating modes of the heat exchanger assembly in the cooling system of FIG. 9. The fluid is represented by a dashed line when in a warm state and represented by a solid line when in a cold state. Where the line is dotted, there is no flow of fluid.
[0064] FIG. 10a shows the cooling system from FIG. 9 in recooling mode. In this case, valves V2 and V4 are closed so that lines 30 and 31 are closed. Valve V3 is open so that the fluid heated by heat source Q can flow through lines 29 and 32 to the recooler R. In this case, the three-way valves V1 are closed so that the fluid can flow from line 32 respectively to the first connection piece 1a of the first distributor 1 (inlet distributor) of the two multi-pass heat exchangers and thereby enter the heat exchanger assembly. After the fluid has passed through the multi-pass heat exchangers of the recooler R several times, the cooled fluid exits the recooler R at the third connection piece 3 and flows, through the line 33 connected to the third connection piece 3, to the line 9 and from there into tank B in which the cooled fluid is stored.
[0065] In the emptying mode shown in FIG. 10b, valves V2 and V4 are open and valve V3 is closed. The three-way valves V1 are switched so that the fluid can flow from the lower connection pieces 1a, 2a (first and second connection pieces) into the fluid line 9 connected to these connection pieces and from there directly into tank B. During emptying of the recooler R, the fluid heated by the heat source Q is returned to tank B via the branch line 30 when valve V4 is open, without the fluid being directed through recooler R.
[0066] In the filling mode shown in FIG. 10c, the valves V2 and V4 are closed and valve V3 is open. The three-way valves V1 are controlled in such a way that the fluid heated by the heat source Q is conducted via the lines 29 and 32 to the lower connection pieces 1a, 2a (first and second connection pieces) of the multi-pass heat exchangers and enters the recooler R from there. After the heat exchangers of recooler R have been completely filled, the recooler is switched to recooling mode (FIG. 10a).
[0067] FIG. 11 shows an exemplary embodiment of a cooling system in which two heat exchanger assemblies according to the invention can be used as recoolers R1, R2 in parallel or series mode. The two recoolers R1, R2 can, for example, be used simultaneously in series for cooling the fluid used as the heat transfer medium in the cooling system. When the two recoolers R1, R2 are used simultaneously, a maximum cooling capacity of the cooling system is achieved. If a lower cooling capacity is required to sufficiently cool the fluid, one of the two recoolers R1 or R2 can be turned off by the control device S of the cooling system.
[0068] In series mode, in which both recoolers R1, R2 are operated simultaneously to cool the fluid, valves V2 and V4 are closed and valve V3 is open so that the fluid heated by heat source Q can be introduced into both recoolers R1, R2 respectively through first connection piece 1a. The fluid cooled in the recoolers R1, R2 exits the recoolers R1, R2 at the third connection piece 3 in each case and flows through the fluid line 9 connected to the third connection piece 2a into the tank B (as shown in FIG. 11).
[0069] In the operating mode of the cooling system of FIG. 11 shown in FIG. 12a, valves V3 and V4 are closed and valve V2 is open. As a result, only the second recooler R2 is operated in recooling mode. The first recooler R1 is in a standby mode, in which no fluid is conducted through the pipelines of the first recooler R1.
[0070] In the operating mode shown in FIG. 12b, with valve V3 open and valves V2 and V4 closed, the second recooler R2 is operated in recooling mode, in which the fluid heated by the heat source Q is introduced via the first connection piece 1a into the heat exchangers of the second recooler R2, where it is cooled, and is ultimately directed out of the second recooler R2 through the second connection piece 2a via the fluid line 9 connected to the third connection piece 3 and conducted into tank B. At the same time, the first recooler R1 is operated in filling mode, in which the fluid is simultaneously introduced into all of the pipelines 5 of the first recooler R1 via the first connection piece 1a and the second connection piece 2a of the heat exchangers in order to completely fill the recooler R1 with fluid.
[0071] To control the heat exchanger assembly according to the invention in the various operating modes, conveniently a plurality of sensors S1, S2 is used, with which ambient parameters, such as outside temperature (T.sub.U) and/or wind speed (v) can be detected and transferred to a control device S for processing. In addition to the ambient parameters, the inlet temperature (.sub.in) of the fluid entering the heat exchanger assembly, the temperature of the fluid in the deflection distributors 4, 6, and the (hydrostatic) pressure (p) and/or the flow rate of the fluid entering the inlet distributor 1 are conveniently detected via additional sensors T1, T2, P.
[0072] The control device which is denoted by reference sign S in the diagram of the cooling system in FIG. 9a is coupled to the valves V, V1, V2, V3, V4 in order to control them. The measured values detected by the sensors S1, S2; T1, T2, P are transferred to the control device, and the control device calculates an output temperature (T.sub.out) of the fluid as it exits the heat exchanger assembly based on the detected measured values. The calculation of the value of the outlet temperature (T.sub.out) also takes into account the parameters of the heat exchanger assembly, in particular its thermal capacity, the dimensioning of the heat exchangers, the number of passes of the fluid through the pipelines, the fluid used as the heat transfer medium and the volume flow rate of the fluid through the pipelines, in order to determine a (maximum) cooling of the fluid when emptying the heat exchanger assembly.
[0073] The control device controls the valves of the heat exchanger assembly so that the heat exchanger assembly is operated in recooling mode as long as the calculated outlet temperature (T.sub.out) is greater than or equal to a predetermined limit value (T.sub.min). As soon as the calculated output temperature (T.sub.out) falls below the limit value (i.e., when T.sub.out>T.sub.min), the heat exchanger assembly is switched to emptying mode. This is done, for example, by electrically or pneumatically actuating the valves V, V1, V2, V3, V4.
[0074] The predetermined limit value (T.sub.min) is conveniently above the freezing point of the fluid used as the heat transfer medium by a value Δ (i.e., above 0° C. for water), wherein the value Δ represents a safety distance from the freezing point. Therefore, even in the event of rapid emptying, it is ensured that the fluid does not freeze if there is a risk of frost.
[0075] Preferably, the value Δ (and thus, when water is used as the heat transfer medium, the limit value T.sub.min=0° C.+Δ) is between 2° C. and 7° C.
[0076] Once the heat exchanger assembly has been completely emptied, it is left in a standby mode, in which the heat exchangers are not filled with fluid. In standby mode, it is monitored whether the risk of frost has passed or is ongoing by calculating the predicted output temperature (T.sub.out) based on the detected ambient parameters and comparing it with the limit value. Once the calculated outlet temperature (T.sub.out) is greater than or equal to the predetermined limit value (T.sub.min), the control device switches the heat exchanger assembly from standby mode into filling mode. After the heat exchanger assembly has been completely filled, it is switched to recooling mode and operated until the calculated outlet temperature (T.sub.out) is below the limit value.
[0077] In the exemplary embodiment shown in FIG. 11, the heat exchanger assembly comprising a plurality of heat exchangers is controlled by the control device in such a way that the individual multi-pass heat exchangers can be operated independently of one another in the various operating modes. In the process, the control device controls the number of heat exchangers operated in recooling mode as a function of the detected ambient parameters and/or the detected input temperature (T.sub.in) of the fluid in order to be able to provide a required cooling capacity. Expediently, the fluid volume conducted through the heat exchanger assembly per unit of time remains the same regardless of the number of heat exchangers operated in recooling mode. In the process, the control device monitors whether the temperature of the fluid cooled in the heat exchanger assembly and stored in the tank is within a preferred temperature range between a minimum and a maximum temperature. The preferred temperature range may be, for example, between 15° C. and 22° C.
