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(11) | EP 1 312 877 A2 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Multi-function cooling unit for air-conditioning systems |
| (57) Multi-function cooling unit (1) for air-conditioning systems comprising a first heat
exchanger (2), with which a refrigerant exchanges heat with the outside environment;
a second heat exchanger (3) with which said refrigerant exchanges heat with a first
liquid circulating in the hydraulic circuit of said air-conditioning system; a third
heat exchanger (4), where the refrigerant exchanges heat with a second liquid; a compression
device (5) for compressing said refrigerant, at which said refrigerant is compressed;
and a distributor (6) for distributing said refrigerant, and which selectively connects
said compression device (5) to said first (2), second (3), and/or third heat exchanger
(4); said distributor (6) comprises a first (23) and a second reversing four way valves
(24) connected in series with respect to each other. |
[0002] In particular, this invention is used on a cooling unit for centralized air-conditioning systems with heat recovery to be utilized for other uses, to which this text will explicitly refers without loss in generality.
[0003] As known, centralized air-conditioning systems usually comprise of a cooling unit that cools the liquid circulating in the radiators and/or fan-coils that belong to the system, so as they subtract heat from the inside environment in order to lower the air temperature inside the different rooms of the building where they are positioned.
[0004] In air-conditioning systems of larger dimensions, the cooling unit/s works according to the heat pump principle and can cool or heat the liquid circulating inside the hydraulic circuit of the air-conditioning system, so as the radiators and the fan-coils, selectively and according to the seasons, subtract or give heat to the ambient, without using a boiler.
[0005] While in operation the cooling units with heat pump function produce a high quantity of heat. In recent years, in order to optimise the use of the environmental resources, some big firms in this sector have recovered a part of the produced heat to produce hot water for sanitary or other uses. A function that up to that moment was made by boilers not comprised in the air-conditioning system.
[0006] Unfortunately, the presence of this new function has much increased the complexity of the layout of the cooling units that now have to be able to cool or heat, according to the ambient conditions, the liquid circulating in the air-conditioning system, assuring in any case the sufficient production of heat used and, under request, to also produce hot water for sanitary or for other uses.
[0007] Unfortunately, this higher complexity of the cooling units has much worsened their reliability , with consequent increase in operating costs that has limited strongly their diffusion.
[0008] The purpose of this invention is to make a cooling unit for air-conditioning systems with heat recovery, free from the above mentioned drawbacks.
[0009] With this invention we have designed a multi-function cooling unit for air-conditioning systems comprising of a first heat exchanger, with which a refrigerant exchanges heat with the outside environment; a second heat exchanger with which the refrigerant exchanges heat with a first liquid circulating in the hydraulic circuit of said air-conditioning system; a third heat exchanger, whit which the refrigerant exchanges heat with a second liquid; a compression device of the refrigerant, for compressing said refrigerant; and a distributor of the refrigerant, that selectively connects the compression device with said first, second, and/or third heat exchangers; the distributor comprises a first and a second reversing four way valves connected in series in respect to each other.
[0010] This invention will be now described with reference to the attached drawings, that show one example, but is in no way limited to the example mentioned in this document, where:
- figure 1 shows in a schematic way a multi-function cooling unit for air-conditioning systems made according to the precepts of this invention;
- figure 2 show in a schematic way and with components removed, for clarity, a component of the cooling unit illustrated in figure 1;
- figures 3,4,5 and 6 show in a schematic way the cooling unit of figure 1 in four different operational modes.
[0011] Referring to figure 1, with number 1 is indicated a whole multi-function cooling unit, specifically made to be used in building centralized air-conditioning systems. These systems usually include a series of radiators and/or fan-coils properly distributed in the building inside of which the air temperature has to be controlled, and, at least, a cooling unit able to heat or cool the heat conveying fluid (normally water) that is conveyed to said radiators and/or fan-coils, through the hydraulic circuit, in the air-conditioning system itself.
[0012] The cooling unit 1 works according to the heat pump principle that permit to transfer heat from one ambient to another, using a refrigerant in gas state in a closed thermodynamic cycle as, for example, a Carnot cycle. The thermodynamic principles used in heat pump units are widely known and they will not be further explained.
[0013] The cooling unit 1 includes a first heat exchanger 2, with which the refrigerant exchanges heat with the outside environment; a second heat exchanger 3, with which the refrigerant exchanges heat with the conveying liquid that flows into the radiators and/or to the fan-coils of the hydraulic circuit of the air-conditioning system; and a third heat exchanger 4, with which the refrigerant exchanges heat with a second liquid that is used for other uses not directly referred to the temperature control inside the building, as, for example, the production of hot water for sanitary use.
[0014] The cooling unit 1 includes, also, a compression device 5 for compressing the refrigerant (for example with an adiabatic compression), so that the pressure of the refrigerant outgoing the compression device 5 is higher than the pressure that the refrigerant had in the suction inlet of the compression device itself, and a refrigerant distributor 6, that selectively connects, under control and in the proper way, the delivery 5a and the suction side 5b of the compression device 5 with heat exchangers 2 ,3 and 4.
[0015] Moreover, the distributor 6 selectively connects the delivery 5a and the suction side 5b of the compression device 5 to heat exchangers 2 , 3 and 4 , so as to enable the cooling unit 1, on choice, to :
chill the heat conveying liquid circulating in the hydraulic circuit of the air-conditioning system, transferring heat to the outside environment;
chill the heat conveying liquid circulating in the hydraulic circuit of the air conditioning system, transferring heat to outside environment
and/or to the liquid that used for other purposes not directly referable to the temperature control inside the building;
heat the heat conveying liquid that circulating in the hydraulic circuit of the air-conditioning system, taking heat from the outside environment; or
heat the heat conveying liquid circulating in the hydraulic circuit of the air conditioning system and/or the liquid that is used for other purposes not directly referable to the temperature control inside the building, taking heat from the external ambient.
[0016] In the following text, for convenience, the description will explicitly be referred to the production of hot water for sanitary uses, without for this excluding the utilization of the second liquid for other purposes.
[0017] Heat exchangers 2 and 3 and the compression device 4 are widely used in this sector and so, here, will be not described in details.
[0018] Referring to figure 1, heat exchanger 2 permits the heat exchange between the refrigerant and the outside environment in such a way as to cause the condensation or the evaporation of the refrigerant, depending on the difference in temperature between the refrigerant and the external temperature.
[0019] Moreover, if the refrigerant that goes into the heat exchanger 2 has a temperature higher than the outside environment one, heat exchanger 2 permits the flowing refrigerant to cool progressively transferring heat to the outside environment, with the possibility to change the state from gas to liquid.
[0020] On the contrary, in case that the refrigerant that is going into heat exchanger 2 has a lower temperature than the outside environment one, heat exchanger 2 permits the refrigerant, that flows through the exchanger itself, to warm up progressively taking heat from the outside environment, with the possibility to change the state from liquid to gas.
[0021] In the illustrated example, heat exchanger 2 is provided with two inlets and two outlets for the refrigerant that are properly connected between them in order to have, inside heat exchanger 2, a cooling path, flowing into which the refrigerant with high temperature progressively cools giving heat to the outside environment with the possibility to change state from gas to liquid, and a heating path, flowing into which the refrigerant with low temperature grows progressively hot taking heat from the outside environment with the possibility to change state from liquid to gas.
[0022] In the illustrated example, Moreover, heat exchanger 2 is a forced air heat exchanger for external installation of known kind, that is provided with an inlet 2a for the high temperature refrigerant in gas state, with an outlet 2b for the low temperature refrigerant in liquid state, with an inlet 2c for the low temperature refrigerant in liquid state , and finally with an outlet 2d for the high temperature refrigerant in gas state that is inlet 2a.
[0023] Inlet 2a and the outlet 2b of heat exchanger 2 are the limits of the cooling path and are connected the first directly to the distributor 6 by a first joint pipeline 7, and the second directly to heat exchanger 3 by a second joint pipeline 8, along which are positioned a check valve 9, a drier filter 10 both of known kind. The check valve 9 is orientated in order to permit the downflow of the refrigerant only from heat exchanger 2 to the drier filter 10. Inlet 2c and the outlet 2d of heat exchanger 2 are, instead, the limits of the heating path, and are connected the first directly to heat exchanger 3 by a joint pipeline 11 that joints itself to pipeline 8 immediately downstream of the drier filter 10, and a second directly to the distributor 6 by pipeline 7. On pipeline 11 is positioned an intercepting valve 12 with controlled opening and closing, that selectively does not permit the refrigerant to flow through pipeline 11.
[0024] Always referring to the figure 1, heat exchanger 3 permits the refrigerant to exchange heat with the heat conveying liquid that flows into the radiators and/or fan-coils, in such a way as to increase or reduce the temperature of the refrigerant, taking away or giving heat to the heat conveying liquid circulating in the air-conditioning system.
[0025] Moreover , when the refrigerant that goes into heat exchanger 3 has an higher temperature than the heat conveying liquid one, heat exchanger 3 permits the refrigerant that flows through heat exchanger to cool progressively giving heat to the heat conveying liquid that in this way warms up.
[0026] On the contrary, when the refrigerant that goes in heat exchanger 3 has a lower temperature than the heat conveying liquid one, heat exchanger 3 permits the refrigerant that flows through heat exchanger to warm up progressively absorbing heat from the heat conveying liquid that in this way cools.
[0027] Heat exchanger 3 comprises of a primary circuit through which flows the heat conveying liquid circulating into the radiators and/or fan-coils of the system, and a secondary circuit through which flows the refrigerant.
[0028] Inlet and the outlet of the primary circuit, later on indicated with 3a and 3b, are connected to the hydraulic circuit of the air-conditioning system, whereas inlet and the outlet of the secondary circuit, later on indicated with 3c and 3d, are connected one directly to heat exchanger 2 and the other to the distributor 6. Moreover, inlet 3c of heat exchanger 3 is directly connected to pipeline 8 with interposition of an intercepting valve 13 controlled in opening and closing, that is positioned immediately downstream of the joint between pipeline 11 and pipeline 8, in order to permit the flow of refrigerant to and from the drier filter 10. The outlet 3d of heat exchanger 3 is directly connected to the distributor 6 by the joint pipeline 14.
[0029] For what concerns heat exchanger 4, it permits the heat exchange between the refrigerant and the sanitary water, in order to transfer heat from the refrigerant to the sanitary water increasing its temperature.
[0030] In this case the refrigerant entering heat exchanger 4 has always a higher temperature than the water used for sanitary purposes: consequently flowing through heat exchanger the refrigerant cools progressively giving heat to the sanitary water, but not the vice-versa.
[0031] In the same way as heat exchanger 3, heat exchanger 4 is comprising of a primary circuit through which flows the sanitary water that has to be heated, and a secondary circuit through which flows the refrigerant.
[0032] Inlet and the outlet of the primary circuit, indicated later on with 4a and 4b, are obviously connected to the hydraulic circuit of the building to be provided with cold and hot water, whereas inlet and the outlet of the secondary circuit, later on indicated with 4c and 4d, are connected one directly to distributor 6, and the other in offtake on pipeline 8 between check valve 9 and drier filter 10.
[0033] Moreover, inlet 4c of heat exchanger 4 is connected by pipeline 15 directly to distributor 6, whereas the outlet 4d of heat exchanger 4 is connected to pipeline 8 by the joint pipeline 16, along which is positioned check valve 17 orientated in such a way as to permit the refrigerant to flow only from heat exchanger 4 to pipeline 8.
[0034] Referring to the figure 1, the compression device 5 of the refrigerant is, as said before, of known kind and consists of a traditional screw or piston (or similar) compressor 20 for compressing gas state refrigerants, and a liquid/gas separation tank 21, positioned upstream of the suction inlet of compressor 20 in order to avoid the refrigerant in liquid state to reach the suction inlet of compressor 20, damaging it irreparably. The refrigerant compression device 5 also comprises of a check valve 22, positioned immediately downstream of the delivery outlet of compressor 20 and orientated in order to permit the refrigerant to flow only in outlet from the compressor 20 itself.
[0035] Referring to figures 1 and 2, differently from the cooling unit known till now, the distributor 6 of the unit 1 comprises two reversing four way valves with electrical control, later on indicated with 23 and 24, connected in series with respect to each other as will be better explained later.
[0036] The reversing four way valves 23 an 24, in particular, are both slide valves and are provided with four inlets, selectively connectable directly to one another in pairs and that are made to operate alternatively in two distinct operative configurations enabling two of the four inlets of the valve to be directly and alternatively connected either to one or the other of the remaining two inlets of the valve.
[0037] With other words, each of the reversing four way valves 23,24 comprises of two primary and two secondary inlets:
[0038] The primary inlets can be connected selectively and alternately to all of the secondary inlets of the valve, without coming into direct contact with each other.
[0039] Moreover, the reversing four way valve 23 is provided with four inlets, indicated respectively with 23a, 23b, 23c, and 23d, and can take two different operative configurations: in the first operative configuration, inlet 23a is in direct communication with inlet 23b and inlet 23c is in direct communication with inlet 23d; in the second operative configuration, inlet 23a is in direct communication with inlet 23d and inlet 23c is in direct communication with inlet 23b. Is obvious that inlets 23a and 23c are the primary inlets of the reversing four way valve 23, and that inlets 23b and 23d are the secondary inlets of the valve.
[0040] In the same way , the reversing four way valve 24 is provided with four inlets, indicated respectively with 24a, 24b, 24c, and 24d, and can take two different operative configurations: in the first operative configuration, inlet 24a is in direct communication with inlet 24b and inlet 24c is in direct communication with inlet 24d; in the second operative configuration, inlet 24a is in direct communication with inlet 24d and inlet 24c is in direct communication with inlet 24b. Is obvious that inlets 24a and 24c are the primary inlets of the reversing four way valve 24, and that inlets 24b and 24d are the secondary inlets of the valve.
[0041] For what concerns the connection between the reversing four way valves 23 and 24 and between these last ones and the other components of the cooling unit 1, inlet 23a of the reversing four way valve 23 is connected to the delivery 5a of the compression device 5 by pipeline 25; inlet 23b of the reversing four way valve 23 is connected directly to inlet 24a of the reversing four way valve 24 making so the cascade connection; inlet 23c of the reversing four way valve is connected by pipeline 26 to the suction side 5b of the compression device 5 and also to inlet 24c of the reversing four way valve 24; finally inlet 23d of the reversing four way valve 23 is connected directly to pipeline 15 that comes out from heat exchanger 4.
[0042] The reversing four way valve 24 has, as said before, inlets 24a and 24c in direct connection respectively to inlets 23b and 23c of the reversing four way valves 23, whereas inlet 24b and 24d are connected the first to heat exchanger 2 by pipeline 7 and the second to the outlet 3d of heat exchanger 3 by pipeline 14.
[0043] Before going on with the description, it is appropriate to underline that the cascade connection between the reversing four way valves 23 and 24 is made connecting directly one of the two secondary inlets of the fist valve, that is inlet 23b of the reversing four way valve 23, to one of the two primary inlets of the second valve, that is inlet 24a of the reversing four way valve 24.
[0044] With reference to figure 1, the cooling unit 1 finally comprises of at least one expansion valve 27 that permits the quick expansion of the refrigerant, in order to complete the closed thermodynamic cycle in contrast to the compression device 5 that causes, instead ,the quick compression of the refrigerant.
[0045] Moreover, expansion valve 27 makes possible the quick expansion of the flowing refrigerant, in order to make the pressure of the refrigerant outgoing from the expansion valve 27 much lower than the pressure that the refrigerant had in inlet of the valve itself, and it's obviously positioned along pipeline that connects heat exchanger, at which the refrigerant that comes out from the compression device 5 cools, to heat exchanger at which the refrigerant warms up before returning to the compression device 5.
[0046] In the illustrated example, in particular, the cooling unit 1 comprises three expansion valves 27: the first expansion valve 27 is positioned along pipeline 8 between inlet 3c of heat exchanger 3 and the intercepting valve 13, whereas the second and the third expansion valves 27 are positioned along pipeline 11 in correspondence of inlet 2c of heat exchanger 2.
[0047] Referring to figure 1, the cooling unit 1 finally comprises of also a by-pass circuit of the expansion valve 27 positioned along pipeline 8.
[0048] The by-pass circuit comprises of a joint pipeline 28, that has the first extremity connected in offtake to pipeline 8 between inlet 3c of heat exchanger 3 and the expansion valve 27, and the second extremity connected in offtake to pipeline 8 between check valve 9 and drier filter 10; a storage tank 29 of the refrigerant positioned along the joint pipeline 28; and finally a check valve 30 positioned on pipeline 28 between the storage tank 29 and pipeline 10.
[0049] The check valve 30 is orientated in order to permit the downflow of the refrigerant only from the tank 29 to drier filter 10, but not vice-versa.
[0050] The working of cooling unit 1 will be now described under the hypothesis that this is initially in the summer season configuration, without the need to recover heat to assign to other uses. This means, the cooling unit 1 operate only to cool the heat conveying liquid circulating in the hydraulic circuit of the air-conditioning system, transferring heat to the outside environment.
[0051] In this working mode, the reversing four way valves 23 and 24 are both in the first operative position so that inlets 23a,24a are in direct communication with inlets 23b,24b and inlets 23c,24c are in direct communication with inlets 23d,24d, and the intercepting valves 12 and 13 are the first one in closing position and the second one in opening position.
[0052] With reference to figure 3, the refrigerant outgoing from compressor 20 flows through check valve 22 and reaches inlet 23a of the reversing four way valve 23 of the distributor 6. Once reached inlet 23a, the refrigerant flows through the four-way valve 23, reaches inlet 24a of the reversing four way valve 24 and flows along pipeline 7 as far as inlet 2a of heat exchanger 2, at which it gives heat to the outside environment, cooling itself.
[0053] The refrigerant comes out from heat exchanger 2 through outlet 2b and, flowing along pipeline 8, flows through, in sequence, the check valve 9, the drier filter 10, the intercepting valve 13 and finally the expansion valve 27, at which it is subjected to a quick expansion before going in inlet 3c of heat exchanger 3. Inside heat exchanger 3 the refrigerant takes heat from the heat conveying liquid circulating in the hydraulic circuit of the air-conditioning system, to flow, after, along pipeline 14 to distributor 6 and from here again to compressor 20, upon passage in the liquid/gas separator tank 21.
[0054] Moreover, the refrigerant outgoing from heat exchanger 3 flows through pipeline 14 as to reach inlet 24d of the reversing four way valve 24, goes out from inlet 24c of the valve itself and from here flows through pipeline 26 as far as the liquid/gas separator tank 21 which communicates directly with the suction side of the compressor 20.
[0055] It is appropriate to underline that, in this working mode, the suction side 5b of the compression device 5 is in direct communication also with inlet 4c of heat exchanger 4, the latter being able to suck by depression all the refrigerant that is accumulated in heat exchanger 4.
[0056] In this case inlets 23c,23d of the reversing four way valve 23 are directly connected one to the other, consequently the suction side 5b of the compression device 5 is connected by pipelines 26 and 15 with inlet 4c of heat exchanger 4.
[0057] With reference to figure 4, taking into consideration the cooling unit set to summer operation mode, if it is necessary to provide hot water, the electronic control device (not illustrated) - that controls the work of the cooling unit 1 - enables the commutation of the reversing four way valve 23 from the first to the second operative position, putting in direct communication inlet 23a and inlet 23d.
[0058] In this case, the refrigerant outgoing from the compressor 20 flows through the check valve 22, goes into inlet 23a of the reversing four way valve 23 of the distributor 6, goes out from inlet 23d of the reversing four way valve 23, runs through pipeline 15; goes into heat exchanger 4, giving heat to the sanitary water that flows inside the exchanger; flows along pipeline 16; flows through the check valve 17; finally flows along the ending length of pipeline 8 going through, in sequence, the drier filter 10, the intercepting valve 13 and expansion valve 27 at which, as in the previous case, is subjected to a quick expansion before entering in inlet 3c of heat exchanger 3. When the refrigerant goes through heat exchanger 3 takes heat from the heat conveying liquid circulating in the hydraulic circuit of the air conditioning system, increasing its temperature, to flow again towards the distributor 6, and from this last one towards the compressor 20, passing in the liquid gas separator tank 21.
[0059] Moreover, the refrigerant out-coming from heat exchanger flows through pipeline 14; enters in the reversing four way valve 24 from inlet 24d; goes out from the reversing four way valve 24 from inlet 24c; flows through pipeline 26; and finally reaches the liquid-gas separator tank 21 that communicates directly with the suction side of compressor 20.
[0060] As in the previous case, also in this working mode the suction side 5b of the compression device 5 is in direct connection by distributor 6 with the element of the cooling unit 1 that are not used at present, enabling the compression device 5 to suck by depression all the refrigerant that is accumulated in the latter.
[0061] In this case, inlets 23b and 23c of the reversing four way valve 23 are in direct communication with each other, as a consequence the suction side 5b of the compression device 5 is connected by pipelines 26 and 7 directly to inlet 2a of heat exchanger 2, enabling the refrigerant that is in heat exchanger 2 to reach the suction side 5b of the compression device 5.
[0062] With reference to figure 5, in case that it is necessary to heat the heat conveying liquid circulating in the hydraulic circuit of the air-conditioning system without the need of recovery heat to be used for other purposes, that is, if it's necessary to switch to the winter season configuration, the electronic control device (not illustrated) that controls the working of the cooling unit 1 enables the reversing four way valves 23 and 24 in the first and in the second operative position respectively, closes the intercepting valve 13, and finally opens the intercepting valve 12.
[0063] In this case, the refrigerant outgoing from compressor 20 flows through check valve 22, reaches inlet 23a of the reversing four way valve 23 of the distributor 6, goes out from inlet 23b of the reversing four way valve 23, reaches inlet 24a of the reversing four way valve 24, goes out from inlet 24d, flows through pipeline 14 and goes in heat exchanger 3 through the outlet 3d.
[0064] The refrigerant, after having given heat to the heat conveying liquid circulating in heat exchanger 3, goes out from inlet 3c of heat exchanger 3; flows through pipeline 28 flowing through, in sequence, tank 29 and check valve 30; finally reaches pipeline 8.
[0065] Once it reaches pipeline 8, the refrigerant flows through drier filter 10 and then into pipeline 11, going through the intercepting valve 12 and expansion valve 27 before coming in inlet 2c of heat exchanger 2. In the same way of the previous cases, going through the expansion valve 27, the refrigerant is subjected to a quick expansion with the following quick drop of its temperature.
[0066] Inside heat exchanger 2 , the refrigerant warms up taking heat from the outside environment, goes out from exchanger 2 through inlet 2d so as to flow along pipeline 7 as far as inlet 24b of the reversing four way valve 24.
[0067] When inside the reversing four way valve 24, the refrigerant is deviated towards inlet 24c of the valve itself, from where it goes on through pipeline 26 as far as the liquid/gas separator tank 21 that communicates directly with the suction side of the compressor 20.
[0068] As in the previous case, also in this working mode the suction side 5b of the compression device 5 is in direct communication through the distributor 6 with the element of the cooling unit 1 that are not used at present, enabling the compression device 5 to suck by depression all the refrigerant that is accumulated.
[0069] Moreover, the suction side 5b of the compression device 5 is in direct connection also with inlet 4c of heat exchanger 4 in such a way as to suck by depression all the refrigerant that is accumulated inside heat exchanger 4. In this case, the reversing four way valve 23, having inlets 23c and 23d in direct connection one to another, puts pipeline 26 in direct connection to pipeline 15, connecting the suction side 5b of the compression device 5 to inlet 4c of heat exchanger 4.
[0070] With reference to figure 6, starting from the cooling unit 1, set in winter season operation, in the case that it is necessary to produce hot water , the electrical control device (not illustrated) that controls the working of the cooling unit 1 puts the reversing four way valves 23 and 24 both in the second operative position, taking the intercepting valve 13 still closed and the intercepting valve 12 opened.
[0071] In this case , the refrigerant outcoming from the compressor 20, flows through the check valve 22; goes in the reversing four way valve 23 of distributor 6 through inlet 23a; goes out of the reversing four way valve 23 through inlet 23d; flows through pipeline 15; goes through heat exchanger 4, giving heat to the sanitary water that flows in heat exchanger; flows through pipeline 16; goes through the check valve 17; and finally goes all over the ending length of pipeline 8 as far as the drier filter 10.
[0072] When passed the drier filter 10, the refrigerant deviates in pipeline 11, goes through intercepting valve 12 and the expansion valve 27, and then, reaches inlet 2c of heat exchanger 2. As in the previous cases, the refrigerant is subjected to a quick expansion with following quick drop if its temperature.
[0073] Inside heat exchanger 2, the refrigerant warms up taking heat from the external environment, goes out from heat exchanger through inlet 2a so to flow along pipeline 7 as far as inlet 24b of the reversing four way valve 24.
[0074] When inside the reversing four way valve 24, the refrigerant is deviated towards inlet 24c of the valve, from where flows through pipeline 26 as far as the liquid gas separator tank 21 that communicates directly with the suction side of compressor 20.
[0075] Also in this working modality, the suction side 5b of the compression device 5 is in direct communication, through distributor 6, with the components of the cooling unit 1 that are not used at present, so that the compression device 5 can suck by depression all the refrigerant that is accumulated inside these last ones.
[0076] Moreover, the suction side 5b of the compression device is in direct communication also with outlet 3d of heat exchanger 3, enabling compression device 5 to suck by depression all the refrigerant that is accumulated inside heat exchanger 3. In this case, the reversing four way valves 23 and 24 put in direct contact pipeline 26 and pipeline 14, connecting the suction side 5b of the compression device 5 directly to inlet 3d of heat exchanger 3.
[0077] The last working modality described is used also during the summer season, when the heat conveying liquid is in temperature and is necessary heat the sanitary water that circulates in heat exchanger 4.
[0078] The benefits of the cooling unit 1 are obvious: the new distributor 6 of the refrigerant has simplified a lot the structure of the cooling unit 1, reducing strongly the number of components with a great advantage in reliability. In addition, the cooling unit 1 made in this way uses a lower quantity of refrigerant than traditional cooling units, reducing the pollution risks due to accidental leakage.
1. A multifunction cooling unit (1) for air-conditioning systems, comprising a first
heat exchanger (2), at which a refrigerant exchanges heat with the outside environment;
a second heat exchanger (3), at which said refrigerant exchanges heat with a first
liquid circulating in the hydraulic circuit of said air-conditioning system; a third
heat exchanger (4), at which said refrigerant exchanges heat with a second liquid;
a compression device (5) for compressing said refrigerant, and at which said refrigerant
is compressed; and a distributor (6) for distributing said refrigerant, and which
selectively connects said compression device (5) to said first (2), said second (3),
and/or said third (4) heat exchanger; said cooling unit (1) being characterized in that said distributor (6) comprises a first (23) and a second (24) four-way valve connected
in series with respect to each other.
2. A cooling unit as claimed in Claim 1, characterized in that said first (23) and said second (24) four-way valve comprising of four inlets (23a,
23b, 23c, 23d) (24a, 24b, 24c, 24d) selectively connectable directly to one another
in pairs.
3. A cooling unit as claimed in Claim 2, characterized in that said first (23) and said second (24) four-way valve both comprise a pair of primary
inlets (23a, 23c) (24a, 24c) and a pair of secondary inlets (23b, 23d) (24b, 24d);
each of said primary inlets (23a, 23c) (24a, 24c) of said four-way valve (23, 24)
being connectable selectively and alternatively to any one of said secondary inlets
(23b, 23d) (24b, 24d) of the four-way valve (23, 24).
4. A cooling unit as claimed in Claim 3, characterized in that one (23b) of the secondary inlets (23b, 23d) of said first four-way valve (23) is
connected to one (24a) of the primary inlets (24a, 24c) of the second four-way valve
(24).
5. A cooling unit as claimed in any one of Claims 3 and 4, characterized in that one (23a) of the two primary inlets (23a, 23c) of said first four-way valve (23)
is connected to the delivery side (5a) of said compression device (5).
6. A cooling unit as claimed in any one of Claims 3 to 5, characterized in that one (23c) of the two primary inlets (23a, 23c) of said first four-way valve (23)
and one (24c) of the two primary inlets (24a, 24c) of said second four-way valve (24)
are both connected to the intake side (5b) of said compression device (5).
7. A cooling unit as claimed in any one of Claims 3 to 6, characterized in that one (23d) of the two secondary inlets (23b, 23d) of said first four-way valve (23)
is connected to said third heat exchanger (4).
8. A cooling unit as claimed in any one of Claims 3 to 7, characterized in that one (24b) of the two secondary inlets (24b, 24d) of said second four-way valve (24)
is connected to said first heat exchanger (2).
9. A cooling unit as claimed in any one of Claims 3 to 8, characterized in that one (24d) of the two secondary inlets (24b, 24d) of said second four-way valve (24)
is connected to said second heat exchanger (3).
10. A cooling unit as claimed in any one of the foregoing Claims, characterized in that said first (23) and said second (24) four-way valve are slide valves.