FREECOOLING UNIT FOR TEMPERATURE MANAGEMENT SYSTEM

Abstract

A free cooling unit including a heat exchanger to allow heat exchange between a first fluid and a second fluid; a first pumping assembly to pump the first fluid through a first hydraulic circuit from a first inlet port of the unit to a first outlet port of the unit; a second pumping assembly to pump the second fluid through a second hydraulic circuit from a second inlet port of the unit to a second outlet port of the module and a control module to control the functioning of the unit. The unit further includes a diverter assembly arranged between the first pumping assembly and the heat exchanger and configured to switch between a first state in which the first fluid is directed through the heat exchanger before reaching the first outlet port and a second state in which the first fluid is directly directed to the first outlet port.

Claims

1-11. (canceled)

12. A cooling unit, comprising: a first inlet port; a first outlet port; a second inlet port; a second outlet port; a heat exchanger configured to allow a heat exchange between a first fluid and a second fluid; a first pumping assembly configured to pump the first fluid through a first hydraulic circuit from the first inlet port of the unit to a first outlet port of the unit; a second pumping assembly configured to pump the second fluid through a second hydraulic circuit from the second inlet port of the unit to the second outlet port of the unit, and a control module configured to control the functioning of the unit, the cooling unit further comprising a diverter assembly arranged between the first pumping assembly and the heat exchanger and configured to switch between a first state in which the first fluid is directed through the heat exchanger before reaching the first outlet port and a second state in which the first fluid is directly directed to the first outlet port, and wherein the control module is configured to switch the diverter assembly in the first state when an external ambient temperature is lower than a temperature of the second fluid entering the unit through the second inlet port reduced by a predetermined value and for switching the diverter assembly in the second state when the external ambient temperature is greater than or equal to the temperature of the second fluid entering the unit through the second inlet port reduced by the predetermined value.

13. The unit according to claim 12, further comprising a further diverter assembly arranged between the second pumping assembly and the second outlet port in parallel to the heat exchanger, said further diverter assembly configured to switch between a first state in which the second fluid flows through the heat exchanger before reaching the second outlet port and a second state in which the second fluid is directly directed to the second outlet port, and wherein the control module is configured to switch the further diverter assembly into the first state when an external ambient temperature is lower than the temperature of the second fluid entering the unit through the second inlet port reduced by the predetermined value and to switch the further diverter assembly into the second state when the external ambient temperature is greater than or equal to the temperature of the second fluid entering the unit through the second inlet port reduced by the predetermined value.

14. The unit according to claim 12, wherein the diverter assembly comprises: a first valve hydraulically connected in series with a discharge outlet of the first pumping assembly and in parallel to inlet and outlet ports of the heat exchanger through which the first fluid flows, and a second valve hydraulically connected in series with the discharge outlet of the first pumping assembly and in series with the inlet port of the heat exchanger through which the first fluid flows, and wherein in the first state of the diverter assembly, the first valve is closed and the second valve is open, while in the second state of the diverter assembly the first valve is open and the second valve is closed.

15. The unit according to claim 14, wherein the first pumping assembly comprises a first pump and a second pump hydraulically connected in parallel with each other, and wherein, when at least one between the first pump and the second pump malfunctions, the control module is configured to switch the diverter assembly in an intermediate state between the first state and the second state, in the intermediate state both the first valve and the second valve being at least partially open so as to reduce a pressure drop experienced by the first pumping assembly.

16. A system for managing the temperature of a load, comprising a heat exchange unit for exchanging heat with the external environment, a refrigeration unit and a free cooling unit according to claim 12, wherein the heat exchange unit for exchanging heat with the external environment, the refrigeration unit and the free cooling unit are hydraulically connected to each other to define a first hydraulic circuit in which the first fluid flows, the first hydraulic circuit comprising the first pumping assembly, the first diverter assembly and the heat exchanger of the free cooling unit, a condenser of the refrigeration unit and a heat exchanger of the heat exchange unit, and where the cooling unit and the free cooling unit are hydraulically connected to each other to define a second hydraulic circuit in which the second fluid flows, the second hydraulic circuit comprising the second pumping assembly, and the heat exchanger of the free cooling unit, and an evaporator of the refrigeration unit and a heat exchanger associated with the load.

17. The system according to claim 16, wherein the heat exchange unit for exchanging heat with the external environment and the refrigeration unit each include a respective control module, and wherein the control module of the free cooling unit is coupled with the control modules of the heat exchange unit for exchanging heat with the external environment and of the refrigeration unit and is configured to receive operating data therefrom and provide operating instructions thereto.

18. A method for controlling a system for managing the temperature of a load, the system defining: a first hydraulic circuit in which a first fluid flows, the first hydraulic circuit comprising a first pumping assembly, a first diverter assembly, a heat exchanger for exchanging heat with a second fluid, a condenser for exchanging heat with a refrigerating fluid, and an additional heat exchanger for exchanging heat with the external environment; a second hydraulic circuit in which the second fluid flows, said second hydraulic circuit comprising a second pumping assembly, the heat exchanger for exchanging heat with the first fluid, an evaporator for exchanging heat with the refrigerant fluid and a heat exchanger associated with the load, and a cooling circuit in which the refrigerant flows, wherein the method comprises: detecting an external ambient temperature and a temperature of the second fluid at the suction of the second pumping assembly; determining whether the external ambient temperature is lower than the temperature of the second fluid at the suction inlet of the second pumping assembly reduced by a predetermined value; in the affirmative case, switching the diverter assembly to a first state in which the first fluid is directed through the heat exchanger before reaching the first outlet port, or in the negative case, switching the diverter assembly to a second state in which the first fluid is directly directed to the first outlet port.

19. The method according to claim 18, wherein the second hydraulic circuit further comprises a further diverter assembly arranged between the second pumping assembly and the evaporator in parallel to the heat exchanger of heat, and wherein the method further comprises: when the external ambient temperature is lower than the temperature of the second fluid at the suction inlet of the second pumping assembly reduced by a predetermined value, switching the further diverter assembly in a first state in which the second fluid is directed through the heat exchanger before reaching the evaporator, or when the external ambient temperature is greater than or equal to the temperature of the second fluid at the suction inlet of the second pumping assembly reduced by the predetermined value, switching the further diverter assembly in a second state in which the second fluid is directly directed to the evaporator.

20. The method according to claim 19, further comprising the step of: when the diverter assembly is in the first state, adjusting the operation of the further heat exchanger so that the temperature of the second fluid leaving the latter reaches a value lower than a reference value of the second fluid.

21. The method according to claim 20, wherein the heat exchanger has a minimum operating flow rate ({dot over (q)}|.sub.3min) allowed by the heat exchanger; the further heat exchanger has a minimum operating flow rate ({dot over (q)}|.sub.1min) allowed by the further heat exchanger, and the condenser has a minimum operating flow rate ({dot over (q)}|.sub.2min) allowed by the condenser, and the method further comprises: when the diverter assembly is in the first state, selecting a highest flow rate among: a minimum operating flow rate ({dot over (q)}|.sub.3min) allowed by the heat exchanger; a minimum operating flow rate ({dot over (q)}|.sub.1min) allowed by the further heat exchanger, and a minimum operating flow rate ({dot over (q)}|.sub.2min) allowed by the condenser.

22. The method according to claim 21, wherein the first pumping assembly comprises two pumps connected together in parallel, the diverter assembly comprises a first valve hydraulically connected in series with a delivery outlet of the two pumps and in parallel to the inlet and outlet ports of the heat exchanger through which the first fluid flows, and a second valve hydraulically connected in series with the delivery outlet of the two pumps and in series with the inlet port of the heat exchanger through which the first fluid flows, and the method further comprises: identifying a malfunction of one of the pumps of the first pumping assembly, and when a malfunction is identified, progressively bringing the first valve and the second valve to a partially open state in order to reduce the pressure drops experienced by the functioning pump.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0074] The invention will be described below with reference to some examples, provided for explanatory and non-limiting purposes, and illustrated in the accompanying drawings. These drawings illustrate different aspects and embodiments of the present invention and, where appropriate, reference numerals illustrating similar structures, components, materials and/or elements in different figures are indicated by similar reference numbers.

[0075] FIG. 1 is a simplified diagram of the hydraulic circuit of a temperature management system according to an embodiment of the present invention connected to a heat load;

[0076] FIG. 2 is a simplified block diagram of the control electronics of the temperature management system of FIG. 1;

[0077] FIG. 3 is a flow diagram of a control procedure of the system according to an embodiment of the present invention, and

[0078] FIG. 4 is a flow diagram of a safety procedure of the system according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0079] While the invention is susceptible to various modifications and alternative constructions, certain preferred embodiments are shown in the drawings and are described hereinbelow in detail. It must in any case be understood that there is no intention to limit the invention to the specific embodiment illustrated, but, on the contrary, the invention intends covering all the modifications, alternative and equivalent constructions that fall within the scope of the invention as defined in the claims.

[0080] The use of “for example”, “etc.”, “or” indicates non-exclusive alternatives without limitation, unless otherwise indicated. The use of “includes” means “includes, but not limited to” unless otherwise stated.

[0081] Referring to FIGS. 1 and 2, a temperature management system, briefly indicated hereinafter as ‘system 1’ is described, according to an embodiment of the present invention. The system 1 is configured to control a temperature TL of a load L, for instance a data centre in which it is desired to keep the inner temperature within a desired value or range of values ΔT.sub.L.

[0082] The system 1 comprises an air cooling unit, or dry cooler 10, a refrigeration unit, or chiller 20 and a free cooling unit, or free cooler 30 and connected between each other hydraulically and electrically as hereinafter described.

[0083] The dry cooler 10 comprises an air/fluid heat exchanger 11—for instance provided with one or more fans to force an air flow through a finned heat exchanger through which the first fluid f1 (e.g. water) passes.

[0084] The chiller 20 comprises an evaporator 21, a condenser 23, a compressor 25 and a thermal expansion valve 27, where such components are connected with each other to form a hydraulic circuit wherein the compressor 25 and the thermal expansion valve 27 are in parallel between evaporator 21 and condenser 23 (as shown in FIG. 1), in order to allow a refrigerant fluid f.sub.R (e.g., R-134a) to circulate.

[0085] Furthermore, an outlet port for the refrigerant liquid—the first fluid f1 in the example considered—of the condenser 23 is, preferably, connected hydraulically to a three-way valve 40, while an outlet port for refrigerated liquid—a second fluid f2 (e.g. water)—of the evaporator 21 is, preferably, connected hydraulically to a heat exchanger 50 associated to the load L to exchange heat therewith—for example, the heat exchanger 50 may comprise one or more water/water exchanger (of the shell and tube, plate, immersed finned, coiled, tube in tube, tank or hydraulic collector type, etc.) or air/water heat exchanger (of the finned, fan coil, radiator type, etc.).

[0086] In the embodiments of the present invention the free cooler 30 comprises a heat exchanger 31,—for instance a plate heat exchanger—, a first pumping assembly 32, preferably comprising a pair of pumps 32a and 32b in parallel, at a variable flow rate and/or speed, a second pumping assembly 33, in the non-limiting example considered as comprising a single pump, at a variable flow rate and/or speed, a first diverter assembly 34, preferably comprising a pair of adjustable valves 34a, 34b, and a second diverter assembly 35, preferably comprising a valve.

[0087] Preferably, the suction inlets of the pumps 32a and 32b are hydraulically connected to a first inlet port 36i of the free cooler 30—configured for the hydraulic connection to an outlet port of the dry cooler 10, to receive the first fluid f1—, while the discharge outlets of the pumps 32a and 32b are hydraulically connected to the diverter assembly 34. The diverter assembly 34 is hydraulically connected to a first inlet (refrigerant fluid inlet) of the heat exchanger 31 and to a first outlet port 36o of the free cooler 30—which is connected to a condenser 23 inlet (refrigerant fluid inlet) of the chiller 20 and to the three-way valve 40—to provide the first fluid f1. The same outlet port 36o is hydraulically connected to a first outlet (refrigerant fluid outlet) of the heat exchanger 31 from which the fluid f1 exits after passing through the heat exchanger 31. In detail, one first valve 34a is interposed between the pumps 32a and 32b and the heat exchanger 31, while a second valve 34b is interposed between the pumps 32a and 32b and the outlet port 36o, with the first outlet of the heat exchanger 31 connected to the outlet port 36o, downstream of the second valve 32b.

[0088] Preferably, the pump suction inlet of the second pumping assembly 33, briefly hereinafter referred to as ‘third pump 33’, is hydraulically connected to a second inlet port 37i of the free cooler 30—configured to be connected to the heat exchanger 50 associated to the load L, in order to receive the second fluid f2. The discharge outlet of the pump 33 is connected to a second inlet (refrigerated fluid inlet) of the heat exchanger 31 and to the valve of the second diverter assembly 35, briefly hereinafter referred to as ‘third valve 35’. The third valve 35 and a second outlet (refrigerated fluid outlet) of the heat exchanger 31 are connected to a second outlet 37o of the free cooler 30—configured to be connected to a refrigerated liquid inlet of the evaporator 21 of the chiller 20, so that the second fluid f2 passes through the evaporator 21 before being transferred to the load L.

[0089] Finally, the three-way valve 40 is connected to an inlet port of the dry cooler 10, so as to provide the first fluid f1 entering the heat exchanger 11.

[0090] In function, the first cooling fluid f1 circulates in a first hydraulic circuit defined by the pumps 32a and 32b, the valves 34a, 34b and 40, the heat exchangers 11 and 31, the three-way valve 40 and the condenser 23. In particular, the heat exchanger 31 of the free cooler 30 is placed in series with the condenser 23 of the chiller 20. By contrast, the refrigerant fluid f.sub.R circulates in a cooling circuit defined by the condenser 23, the compressor 25, the evaporator 21 and the thermal expansion valve 27. Finally, the second fluid f2 circulates in a second hydraulic circuit defined by the third pump 33, the third valve 35, the heat exchangers 31 and 50 and the evaporator 21. In particular, the heat exchanger 31 of the free cooler 30 is placed in series with the evaporator 21 of the chiller 20.

[0091] As shown in the example of FIG. 2, each of the units 10, 20 and 30 comprises one or more electronic and/or electromechanic components connected between each other to manage the operation of the system 1 in a substantially automatic way.

[0092] The dry cooler 10 preferably comprises an actuating module 110 comprising a circuit adapted to supply and control the rotation speed of the cooling fans. For example, the driving module 110 of the dry cooler 10 comprises a processing component—such as a micro-controller, a PLC, an ASIC, etcetera—and an actuating component—such as a power circuit configured to supply an electric motor of the fans. Advantageously, the dry cooler 10 also comprises a temperature sensor 120 configured to provide a signal indicative of the ambient temperature Ta outside the system 1 and the load L.

[0093] The chiller 20 preferably comprises a control module 210 comprising a circuit adapted to supply and control the compressor 25 functioning. For example, the control module 210 of the dry cooler 20 comprises a processing component—such as a micro-controller, a PLC, an ASIC, etcetera—and an actuating component—such as a power circuit configured to supply the compressor 25. In the embodiment being considered, the control module 210 is also configured to control the switching of the three-way valve 40. Advantageously, the chiller 20 also comprises a plurality of sensors 220 configured to measure functioning parameters of the chiller 20: such as a condenser temperature T.sub.C, an evaporator temperature T.sub.E, an evaporator inlet temperature T.sub.f2E of the second fluid f2 which flows entering the evaporator, an outlet temperature T.sub.f2L of the second fluid f2 which flows to the load L, etcetera.

[0094] The free cooler 30 comprises a control module 310 configured to supply and control the functioning of the pumps 32a, 32b and 33, and of the valves 34a, 34b and 35. For instance, the control module 310 of the free cooler 30 comprises a processing component—such as a micro-controller, a PLC, a micro-processor, a FPGA, an ASIC, etcetera—and an actuating component—such as a power circuit configured to supply and actuate the pumps 32a, 32b and 33, and the valves 34a, 34b and 35 based on instructions provided by the control module 310. Advantageously, the free cooler 30 also comprises a plurality of sensors 320 configured to provide the control module 310 with measures of operating parameters of the free cooler 20: such as a heat exchanger temperature T.sub.S, an inlet temperature T.sub.f1I and, optionally, an outlet temperature T.sub.f1O of the first fluid f1, an inlet temperature T.sub.f2I and, optionally, an outlet temperature T.sub.f2O of the second fluid f2 (substantially corresponding to the evaporator inlet temperature T.sub.f2E), a flow rate of the first fluid f1 and of the second fluid f2, etcetera.

[0095] In addition, the free cooler 30 according to the embodiment of the present invention comprises a communication module 330 electrically connected to the control module 310 of the free cooler 30, to the control module 210 of the chiller 20 and to the driving module 110 of the dry cooler 10, in order to allow a data exchange between the control module 310 of the free cooler 30 and the control modules 110 and 210 of the dry cooler 10 and of the chiller 20. For example, the communication module 330 is configured to connect to the modules 110 and 210 so as to exchange data by means of a known protocol, for example the Modbus protocol. Preferably, the communication module 310 is configured to provide functioning instructions to the control modules 110 and 120 and to receive measures acquired by the sensors 120 and 220 on-board the dry cooler 10 and the chiller 20.

[0096] Preferably, the control module 310 of the free cooler 30 is configured to control the functioning of the whole system 1 based on the measures acquired of the operating parameters of the system 1—temperatures, flow rates, adsorbed electric powers, etcetera—in order to keep the load temperature T.sub.L within the desired range of values ΔT.sub.L. For that purpose, the control module 310 comprises a memory, preferably formed by both volatile and non-volatile portions, in which are stored functioning instructions, data acquired and/or generated during the operation etcetera.

[0097] Having described the structure of the system 1 according to the embodiment of the present invention, a control procedure 600 implemented by the system 1 will now be described.

[0098] Firstly, data provided by the sensors 120, 220 and 320 comprised in the system are acquired, in particular the external ambient temperature Ta and the inlet temperature T.sub.f2I of the second fluid f2, (block 601) and it is verified if the external ambient temperature Ta is lower than the inlet temperature T.sub.f2I of the second fluid f2 in the free cooler 30—i.e., the temperature of the fluid returning from the load L—reduced by a predefined value, called approach A.sub.T (decision block 603). Preferably the approach A.sub.T value is comprised between 0° and 15° C., for instance equal to 5° C. In particular, the approach A.sub.T is selected such to ensure that the heat exchanger 31 is able to promote an efficient heat exchange between the first fluid f1 and the second fluid f2.

[0099] In the negative case (i.e. Ta≥T.sub.f2I−A.sub.T, outlet branch N of the block 603), the valve 34b is closed, while the valves 34a and 35 are open, such to exclude the heat exchanger 31 from the hydraulic circuits—i.e. the first fluid f1 and the second fluid f2 are prevented from flowing through the heat exchanger 31 (block 605).

[0100] Thereafter, the exchanger 11 of the dry cooler 10, in particular the rotation speed of the fans, is adjusted so as to keep substantially constant the inlet temperature T.sub.f1I of the first fluid f1—i.e., the temperature of the first fluid f1 at the inlet port 36i—(block 607). Alternatively, the exchanger 11 of the dry cooler 10 is adjusted such to keep substantially constant the return temperature of the first fluid f1 downstream of the condenser 23 of the chiller 20. At the same time the pumps 32a and 32b are actuated so as to keep the nominal flow rate required by the condenser 23 of the chiller 20.

[0101] The compressor 25 of the chiller 20 is actuated such that the temperature of the second fluid f2 entering the load L—i.e., the outlet temperature T.sub.f2L of the second fluid f2 exiting the evaporator of the chiller 20—keeps substantially constant and equal to a desired value, or forward setpoint T.sub.f2|A such to ensure that the load temperature T.sub.L, is in turn comprised in the range of desired values ΔT.sub.L (block 609). Preferably, the third pump 33 of the free cooler 30 is adjusted such to ensure a constant flow rate of the second fluid f2 and corresponding to a nominal flow rate required by the load 50. Alternatively, the compressor 25 is actuated such to maintain the temperature of the second fluid f2 exiting the load L substantially constant—i.e., the inlet temperature T.sub.f2I of the second fluid f2 in the free cooler 30—and equal to a desired value, or return setpoint T.sub.f2|R such to guarantee that the load temperature T.sub.L, is in turn comprised in the range of desired values ΔT.sub.L.

[0102] Furthermore, the three-way valve 40 is controlled to deviate an amount of the first fluid f1 coming from the free cooler 30 from the condenser 21 of the chiller 20, such to keep constant a condensation pressure inside the condenser 21 (block 611).

[0103] Thereafter, the procedure returns to the decision block 603 to monitor the external ambient temperature Ta in order to identify a reduction in the ambient temperature that is lower than the inlet temperature T.sub.f2I of the second fluid f2 in the free cooler 30.

[0104] In case it is detected an external ambient temperature Ta lower than the inlet temperature T.sub.f2I of the second fluid f2 in the free cooler 30 less the approach A.sub.T (Ta<T.sub.f2I−A.sub.T, outlet branch Y of the block 603), the valve 34b is opened, while the valves 34a and 35 are closed, such to force the first fluid f1 and the second fluid f2 to flow through the heat exchanger 31 (block 613).

[0105] The heat exchanger 11 of the dry cooler 10 is configured to maximise the heat exchange between the first fluid f1 and the external air (block 615). In the embodiments of the present invention, the heat exchanger 11 is controlled to maximise the heat exchange between the first flow f1 and the second flow f2, in particular the heat exchanger 11 is actuated so that the inlet temperature of the second fluid T.sub.f2I—returning from the load L—follows the return setpoint T.sub.f2|R. In a preferred embodiment, the heat exchanger 11 is adjusted such that the inlet temperature T.sub.f2I of the second fluid f2 assumes a value below the return setpoint T.sub.f2|R, for instance lower than a difference value dT comprised between 0.5° and 5° C., for instance 1° C. In other words, the system 1 is adjusted to provide the maximum ‘free’ refrigerating yield available through the free cooler 30 and the dry-cooler 10.

[0106] The pumps 32a and 32b of the free cooler 30 are adjusted in such a way to minimise the difference in logarithmic average temperature or ΔT.sub.ML between the first fluid f1 and the external air to the heat exchanger of the dry cooler 10 at the external ambient temperature Ta (block 617). For this purpose, in one embodiment of the present invention, the pumps 32a and 32b are configured to operate with the flow rate {dot over (q)} having the greatest value between the minimum operating flow rate {dot over (q)}|.sub.1min allowed by the heat exchanger 11 of the dry cooler 10, between the minimum operating flow rate {dot over (q)}|.sub.2 min allowed by the condenser 23 of the chiller 20 and the minimum operating flow rate {dot over (q)}|.sub.3min allowed by the heat exchanger 31 of the free cooler 30. Where minimum operating flow rate means the minimum flow rate of the first fluid f1 which allows a proper heat exchange—i.e. such as to keep a turbulent regime of the first fluid passing through the exchangers 11 and 31, and the condenser 23; in other words the minimum flow rate selected prevents the fluid speed from decreasing too much leading to a laminar regime, with a consequent interruption of the heat exchange.

[0107] Preferably, the third pump 33 of the free cooler 30 is adjusted such to guarantee a constant flow rate of the second fluid f2 and corresponding to a nominal flow rate of the heat exchanger 50 associated to the load L (block 619).

[0108] Consequently, the compressor 25 of the chiller 20 is actuated only when the inlet temperature T.sub.f2I of the second fluid f2 assumes a value greater than the return setpoint T.sub.f2|R, i.e. when it is detected that the outlet temperature T.sub.f2L of the second fluid f2 provided entering the load L assumes a value greater than the forward setpoint T.sub.f2|A (decision block 621).

[0109] In case the outlet temperature T.sub.f2L is greater than the forward setpoint T.sub.f2|A—and, therefore, the inlet temperature T.sub.f2I is greater than the return setpoint T.sub.f2|R—(outlet branch Y of the block 621), the compressor 25 of the chiller 20 is controlled in order to change (reduce) the outlet temperature T.sub.f2L of the second fluid f2 such to reach the forward setpoint T.sub.f2|A through the heat exchange to the evaporator 21 of the chiller 20 (block 623).

[0110] As above, the three-way valve 40 is controlled to deviate part of the first fluid f1 from the condenser 21 of the chiller 20, if necessary, so as to keep a condensation pressure constant inside the condenser 21 (block 625).

[0111] In case the outlet temperature T.sub.f2L is lower than or equal to the forward setpoint T.sub.f2|A—and, therefore, the inlet temperature T.sub.f2I is lower than or equal to the return setpoint T.sub.f2|R—(outlet branch N of the block 621), the compressor 25 is not actuated, in other words, the chiller 20 is off and the management of the temperature T.sub.L of the load L is merely obtained by controlling the functioning of the dry cooler 10 and of the free cooler 30 as above described (block 627).

[0112] Thereafter, the procedure returns to the decision block 603 to monitor the external ambient temperature Ta.

[0113] In one preferred embodiment, the system 1 is configured to carry out a safety procedure 700 to ensure a service continuity also in case of malfunction of the pumping assembly 32. In particular the safety procedure 700 detects when one of the pumps 32a and 32b undergoes a malfunction and ensures a continuity of the system 1 functioning during the malfunction and, possibly, during the repair/replacement/maintenance operations of one of the pumps 32a and 32b.

[0114] The procedure 700 provides to identify the onset of a malfunction condition in the pumps 32a and 32b during the functioning of the system 1 (decision block 701). For instance, a malfunction signal is detected as provided by the pump 32a or 32bla. Alternatively, a malfunction condition may be detected based on the detection of a variation or of an abnormal power adsorption value by one of the pumps 32a or 32b.

[0115] Unless a malfunction is detected (outlet branch N of the block 701), no action is undertaken apart from monitoring the state of the pumps 32a and 32b.

[0116] For merely exemplary purposes, reference is hereinafter made to the case in which the pump 32b undergoes a malfunction, while the pump 32a is still operating. Obviously, the same steps can be performed in the opposite case wherein the pump 32a breaks down, while the pump 32b is still operating.

[0117] When a malfunction of the pump 32b is detected and the external ambient temperature Ta is higher than the inlet temperature T.sub.f2I of the second fluid f2 in the free cooler 30 less the approach A.sub.T (Ta≥T.sub.f2I−A.sub.T)—i.e., the heat exchanger 31 of the free cooler 30 is isolated—(branch Y1 of the block 701), it is provided to increase the pumping speed of the functioning pump 32a until it reaches the desired flow rate value for the pumping assembly 32 or until reaching the maximum speed that the operating pump 32a can reach (block 703).

[0118] Thereafter, the operation monitors again the condition of the pumps 32a at block 701 to continue ensuring the continuity of the system 1 functioning until the malfunction is corrected.

[0119] When a malfunction of the pump 32b is detected and the external ambient temperature Ta is lower than the inlet temperature T.sub.f2I of the second fluid f2 in the free cooler 30 less the approach A.sub.T (Ta≥T.sub.f2I−A.sub.T)—i.e., the heat exchanger 31 of the free cooler 30 is connected in series with the chiller 20 condenser—(branch Y2 of the block 701), it is provided to increase the pumping speed of the functioning pump 32a until it reaches the desired flow rate value for the pumping assembly 32 or until reaching the maximum speed that the functioning pump 32a can reach (block 705).

[0120] Furthermore, it is provided to monitor the speed of the functioning pump 32a (decision block 707).

[0121] No action is undertaken apart from monitoring the speed and flow rate of the functioning pump 32a (outlet branch N of the block 707) until detection of the maximum speed value of the functioning pump 32a being reached.

[0122] Having detected that the minimum flow rate value is reached without having reached the maximum speed of the operating pump 32a (outlet branch Y1 of the block 707), it is provided to proceed controlling the temperature of the load L according to the above described procedure 600 (block 709) and it is provided to return to monitor the condition of the pumps 32a at the block 701 to continue ensuring the continuity of the system 1 functioning until the malfunction is corrected.

[0123] Having detected that the maximum speed is reached for the functioning pump 32a without having reached the minimum flow rate (outlet branch Y2 of the block 707), it is provided to gradually open the valve 34a and gradually close the valve 34b, in order to reduce pressure drops experienced by the pump 32a due to the heat exchanger 31 (block 711).

[0124] In this case the compressor 25 of the chiller 20 is actuated in a way substantially proportional to the valve opening 34a, so as to ensure that the outlet temperature T.sub.f2L is substantially equal to the forward setpoint T.sub.f2|A—and, therefore, the inlet temperature T.sub.f2I is lower than or equal to the return setpoint T.sub.f2|R—(block 713).

[0125] In other words, the opening of the valves 34a and 34b, as well as the functioning of the chiller 20 are modulated such to reduce the pressure drop experienced by the functioning pump 32a, so as to ensure a flow of the first minimum flow f1 in the first hydraulic circuit allowing for the correct functioning of the system 1 and allowing to maintain the temperature T.sub.L of the load L within the range d of desired values ΔT.sub.L.

[0126] Thereafter, the operation monitors again the condition of the pumps 32a at block 701 to continue ensuring the continuity of the system 1 functioning until the malfunction is corrected.

[0127] The invention thus conceived is susceptible to several modifications and variations, all falling within the scope of the inventive concept.

[0128] For example, nothing prevents the first pumping assembly 32 from comprising a different number of pumps, such as a single pump or more than two pumps in parallel. Similarly, the second pumping assembly 33 may also comprise two or more pumps arranged in parallel between each other. In such case it may be provided a procedure for continuing the service which controls the functioning of the pumps of the second pumping assembly 33 in case of malfunction.

[0129] Furthermore, in alternative embodiments (not shown), the pumping assemblies 32 and 34 may be arranged downstream of the hydraulic exchanger with respect to the direction of flows f1 e f2, hence with the suctions inlets connected with the respective outlet ports of the heat exchanger 31 and the discharge outlets connected to the outlet ports 36a and 37o, respectively, of the free cooler 30.

[0130] In one embodiment (not shown), the first diverter assembly 34 comprises a three-way valve rather than a pair of valves as described above in the embodiment shown.

[0131] Furthermore, it is possible to provide simplified embodiments (not shown) without the second diverter assembly.

[0132] It is possible to modify the free cooler 30 to comprise a third inlet port connected to a third outlet port, such to define a duct that allows connecting hydraulically the three-way valve 40 and the heat exchanger 11 of the dry cooler 10. Furthermore, the free cooler may be equipped with one or more flow rate and/or temperature sensors arranged in such duct, in order to monitor operating parameters of the first fluid f1 in such a tract of the first hydraulic circuit.

[0133] In alternative to the dry cooler, the system according to other embodiments of the present invention (not shown) may comprise other heat exchange units for exchanging heat with the external environment, for instance a duly sized cooling tower, an evaporation tower, an adiabatic dry cooler, etcetera.

[0134] Furthermore, it is possible to provide a heat exchanger of the free cooler 30 different from a plate heat exchanger. For instance, in embodiments of the present invention (not shown), the free cooler may comprise any type of water/water exchanger (of the shell and tube, plate, immersed finned, coiled, tube in tube, tank or hydraulic collector type, etcetera).

[0135] In one alternative embodiment, the communication module may be configured to communicate with the chiller or dry cooler with a different protocol and/ or by analog signals. Furthermore, the communication module may optionally provide wired or wireless means to communicate with a remote device. In such case the procedure for service continuity entails to transmit a malfunction signal to the remote device.

[0136] Obviously, alternative embodiments of the free cooler and/or of the whole system 1 may comprise additional hydraulic and/or electronic components such as exclusion valves, escape valves, one-way valves, user interfaces, flow rate sensors, pressure sensors, etcetera. In particular, alternative embodiments of the system 1 comprise one or more temperature sensors arranged on and/or inside the load in order to determine the load temperature T.sub.L and/ or variations thereof.

[0137] As will be clear to the skilled in the art, one or both of the above set forth procedures are comprised in a method for managing the temperature of a load. In addition, one or more steps of the same procedure or of different procedures may be performed in parallel between each other or according to an order different from the above described one. Similarly, one or more optional steps may be added or removed from one or more of the above described procedures. For example, the system 1, in particular the control module 310, may be configured to implement the operations described in blocks 605 to 611 of the parallel procedure 600 rather that in series. In addition or in alternative, also the operations described in blocks 613 to 619, and/or 623 and 625 may be performed in parallel rather than in series.

[0138] Optionally, the three-way valve 40 may be controlled to exclude the condenser 21 of the chiller 20, when the chiller 20 is not on.

[0139] Moreover, all the details can be replaced by other technically equivalent elements.

[0140] In particular, the cooling circuit may have a different structure. For example, in alternative embodiments (not shown) the cooling circuit may comprise an absorption cycle.

[0141] Furthermore, as will be clear to the skilled in the art, the connections between the control modules 110, 210 and 310 may be made by a wired and/or wireless communication channel.

[0142] In practice, the materials used, as well as the contingent shapes and sizes, can be whatever according to the requirements without for this reason departing from the scope of protection of the following claims.