JP2019124396A - Air conditioning system - Google Patents

Abstract

To save energy of an air conditioning system while materializing proper air-conditioning according to fluctuation of cooling load, the air conditioning system comprising a supply air channel in which supply air flows, a heat source part generating cold water, and a heat exchange part capable of cooling the supply air flowing in the supply air channel by heat exchange with the cold water.SOLUTION: The air conditioning system comprises: a heat exchange part 2 which comprises a primary heat exchange part 3 and a secondary heat exchange part 4 disposed at downstream side thereof: a heat source part 50 which is configured to independently generate low-temperature cold water LCW and intermediate-temperature cold water MCW; and a control part 60 which performs such a latent/sensible separation air-conditioning operation that the intermediate-temperature cold water MCW is supplied to the primary heat exchange part 3 and the low-temperature cold water LCW is supplied to the secondary heat exchange part 4 in high cooling load in which cooling load is high. The control part 60 also performs such a large temperature difference air-conditioning operation that cold water is supplied to the secondary heat exchange part 4 and the cold water discharged from the secondary heat exchange part 4 is supplied to the primary heat exchange part 3 in low cooling load in which the cooling load is lower than that in the high cooling load.SELECTED DRAWING: Figure 1

Description

  The present invention can cool the charge air flowing through the charge air passage by heat exchange between the charge air passage through which the charge air flows, the heat source unit generating cold water, and the cold water supplied from the heat source unit. The present invention relates to an air conditioning system provided with a heat exchange unit.

  In the air conditioning system as described above, during the cooling operation in summer, medium temperature cold water of, for example, 13 ° C. is supplied from the heat source unit to the primary heat exchange unit provided on the upstream side in the supply air passage. The latent heat separation air conditioning operation which supplies low temperature cold water of, for example, 6 ° C. lower than the medium temperature cold water from the heat source unit to the secondary heat exchange unit provided downstream of the primary heat exchange unit in the passage Those are known (see, for example, Non-Patent Document 1).

  And in such an air conditioning system, in the latent microscopic separation air conditioning operation, in the primary heat exchange section, sensible heat treatment can be performed in a form of cooling the outside air to a temperature not falling below the dew point by heat exchange with medium temperature cold water, On the other hand, in the secondary heat exchange unit, the latent heat treatment can be performed in a form of cooling the partially cooled external air which is the primary heat exchange unit to a temperature lower than the dew point by heat exchange with low temperature cold water. And, by executing the latent microscope separation air conditioning operation, it is possible to reduce the generation amount of low temperature cold water and to achieve high efficiency.

Mori Building Co., Ltd. Design Planning Department Equipment Design Department Ichiro Omori, "Commissioning Project of Toranomon Hills Mori Tower", [online], published on January 06, 2015, Building Equipment Commissioning Association 2015 Open Symposium, [Dec. 20, 2017] Day Search], Internet (URL: http://www.bsca.or.jp/event/wp-content/uploads/sites/5/2015/01/04_PresentationToranomon-Hills_Omori_Okushi2.pdf)

In the air conditioning system that executes the latent microscopic separation air conditioning operation as described above, there is a problem that the efficiency is lowered at the time of the low cooling load such as the intermediate period when the cooling load is relatively low.
That is, since each heat exchange part is selected on the assumption of the maximum cooling load time, the cooling capacity in each heat exchange part may become excessive at the time of low cooling load. In addition, at the time of low cooling load, it is necessary to reduce the supply amount of cold water to the primary heat exchange unit and the secondary heat exchange unit to correspond to the reduction of the load, but the flow rate for adjusting the supply amount of cold water Due to the restriction of the control valve, it may not be possible to sufficiently reduce the supply of cold water. In this case, the amount of cooling of the primary heat exchange unit and the secondary heat exchange unit becomes excessive, and the difference between the return temperature of the returning cold water and the return cold water in the heat source unit decreases, and the heat efficiency in the heat source unit decreases.

  Furthermore, at the time of low cooling load, by making the amount of heat treated with medium temperature cold water in the primary heat exchange portion larger than the amount of heat treated with low temperature cold water in the secondary heat exchange portion, the return temperature difference on the medium temperature cold water side If the temperature is maintained large, the temperature difference between the low temperature cold water side and the low temperature cold water side decreases as the temperature of the air supplied from the primary heat exchange section to the secondary heat exchange section decreases. For this reason, in the primary heat exchange unit, it is necessary to control the supply amount of medium temperature cold water so that the outlet temperature of air is constant even under a low cooling load, and accordingly, the primary heat exchange unit as well. It is necessary to supply low temperature cold water at the same ratio as the maximum cooling load to medium temperature cold water to the next heat exchange unit.

  In view of this situation, the main object of the present invention is to pass the air supply path by heat exchange between the air supply air path through which the air supply flows, the heat source unit for generating cold water, and the cold water supplied from the heat source unit. An air conditioning system including a heat exchange unit capable of cooling flowing air, and providing a technology capable of achieving energy saving while realizing appropriate air conditioning according to a change in cooling load.

According to a first aspect of the present invention, there is provided an air supply path through which air flows.
A heat source unit for producing cold water,
A heat exchange unit capable of cooling the charge air flowing through the supply air passage by heat exchange with cold water supplied from the heat source unit;
A primary heat exchange portion provided on the upstream side of the air supply path as the heat exchange portion, and a secondary heat exchange portion provided on the downstream side of the primary heat exchange portion in the air supply path; Equipped with
The heat source unit is configured to be able to separately generate low temperature cold water and medium temperature cold water having a temperature higher than the low temperature cold water, respectively.
At the time of high cooling load with high cooling load, the latent heat is supplied from the heat source to the primary heat exchange section from the heat source section, and the low temperature cold water is supplied from the heat source section to the secondary heat exchange section. During the low cooling load, in which the sensible separation air conditioning operation is performed and the cooling load is lower than the high cooling load, the cold water is supplied from the heat source unit to the secondary heat exchange unit and the secondary heat exchange unit And a controller for performing a large temperature difference air conditioning operation for supplying the cold water discharged from the air to the primary heat exchange unit.

  According to this configuration, during high cooling load where the cooling load is relatively high, medium temperature cold water is supplied to the primary heat exchange part from the heat source part and low temperature cold water is supplied from the heat source part to the secondary heat exchange part In the form, the latent-microbe separation air-conditioning operation described above can be performed in which the sensible heat treatment and the latent heat treatment of the air supply can be performed with different cold waters having different temperatures. That is, in this latent microscopic separation air conditioning operation, the primary heat exchange unit cools the relatively high temperature air supply including the outside air and the return air to a temperature not falling below the dew point by heat exchange with medium temperature cold water supplied from the heat source unit. In the secondary heat exchange unit, the cooled air supplied to the secondary heat exchange unit is partially cooled to a temperature lower than the dew point by heat exchange with the low temperature cold water supplied from the heat source unit. The latent heat treatment can be performed in the form of cooling. By performing such latent-microbe separation air-conditioning operation at high cooling load, it is possible to reduce the generation amount of low-temperature cold water which requires a large amount of energy in the heat source section, and to achieve high efficiency.

On the other hand, when the cooling load is relatively low and the cooling load is relatively low, the primary heat exchange unit is supplied with cold water discharged from the secondary heat exchange unit and the secondary heat exchange unit is supplied with cold water from the heat source unit In the aspect, the large temperature difference air conditioning operation described above can be performed, which can maintain a large difference between the temperature of return water and the temperature of return water in the heat source. That is, in this large temperature difference air conditioning operation, in the primary heat exchange section, relatively high temperature air supply including outside air and return air is not wasted by heat exchange with the relatively low temperature cold water discharged from the secondary heat exchange section. It is possible to cool, and in the secondary heat exchange unit, the partially cooled air that is the primary heat exchange unit can be cooled by relatively low temperature cold water supplied from the heat source unit. By performing such a large temperature difference air conditioning operation at a low cooling load, the heat source portion is supplied with cold water while the common heat pump is used to supply cold water to the primary heat exchange portion and the secondary heat exchange portion. It is possible to achieve high efficiency by maintaining a large one.
Therefore, according to the present invention, it is possible to provide an air conditioning system capable of achieving energy saving while realizing appropriate air conditioning according to the fluctuation of the cooling load.

According to a second characteristic configuration of the present invention, the first heat medium supply passage to which the medium temperature cold water is supplied from the heat source unit, and the low temperature cold water and the medium temperature cold water are alternatively supplied from the heat source unit And a second heat medium supply path connected to the heat exchange unit.
A connection destination switching unit capable of switching the connection destination of the first heat medium supply path between the primary heat exchange unit and the secondary heat exchange unit;
The control unit switches the connection destination of the first heat medium supply passage to the primary heat exchange unit in the latent microscopic separation air conditioning operation, and the first heat medium supply passage with respect to the primary heat exchange unit And the low-temperature cold water to the secondary heat exchange unit via the second heat medium supply passage, and the first heat medium supply in the large temperature difference air conditioning operation. The connection destination of the passage is switched to the secondary heat exchange unit, and the cold water can be supplied to the secondary heat exchange unit via both the first heat medium supply passage and the second heat medium supply passage. The point is to

  According to the present configuration, in the latent microscopic separation air conditioning operation, intermediate temperature cold water is supplied to the primary heat exchange unit via the first heat medium supply passage with the connection destination of the first heat medium supply passage as the primary heat exchange unit. However, when configured to supply low temperature cold water to the secondary heat exchange unit via the second heat medium supply passage, in the large temperature difference air conditioning operation, the connection destination of the first heat medium supply passage is subjected to secondary heat exchange As part, cold water can be supplied to the secondary heat exchange part via both the first heat medium supply path and the second heat medium supply path. That is, in the large temperature difference air conditioning operation, the pipe resistance added to the cold water is supplied by supplying the cold water to the secondary heat exchange unit in two systems of the first heat medium supply passage and the second heat medium supply passage. It is possible to achieve further high efficiency by reducing it.

According to a third aspect of the present invention, there is provided a shutoff means capable of shutting off the supply of cold water from the first heat medium supply passage or the second heat medium supply passage,
The number of chilled water systems in which the control unit controls the number of chilled water systems that supply chilled water to the secondary heat exchange unit in a mode that switches the state of the shutoff unit based on the cooling load in the large temperature difference air conditioning operation The point is to execute control.

  According to this configuration, in the case where cold water can be supplied to the secondary heat exchange unit in two systems of the first heat medium supply path and the second heat medium supply path in the large temperature difference air conditioning operation, cooling can be performed. Cold water system number control may be performed which controls the number of cold water systems to the secondary heat exchange unit based on the load. That is, in the large temperature difference air conditioning operation, when the cooling load is relatively high due to the execution of the above-described control of the number of cold water systems, the cold water is divided by two systems of the first heat medium supply passage and the second heat medium supply passage. Is supplied to the secondary heat exchange unit, but if the cooling load decreases, the shutoff means shuts off the supply of cold water from the first heat medium supply passage or the second heat medium supply passage, and the first heat medium is supplied. Cold water can be supplied to the secondary heat exchange unit in one system of the supply path or the second heat medium supply path. Therefore, in the large temperature difference air conditioning operation under a low cooling load, even if the cooling load is further reduced, the amount of cold water supplied is sufficiently reduced to maintain a large temperature difference between the heat sources and keep the feedback temperature difference large. Efficiency can be improved.

The figure which shows the flow state of the heat medium in the latent-microbe isolation | separation air-conditioning driving | operation (parallel supply mode) in the air conditioning system of this embodiment. The figure which shows the flow state of the heat medium in the large temperature difference air conditioning operation (the cascade 2 system supply mode) in the air conditioning system of this embodiment. The figure which shows the flow state of the heat medium in the large temperature difference air conditioning operation (the cascade 1 system supply mode) in the air conditioning system of this embodiment. The figure which shows the flow state of the heat medium in the heating / cooling simultaneous driving | operation (parallel supply mode) in the air conditioning system of this embodiment.

An embodiment of the present invention will be described based on FIGS. 1 to 4.
In the air conditioning system shown in FIGS. 1 to 4 (hereinafter referred to as "the air conditioning system"), the flow path through which the heat medium flows is shown by a thick solid line, and the flow path through which the heat medium does not flow It is shown by a thin solid line.
The air conditioning system mainly includes an air conditioner 1 for supplying a temperature-adjusted supply air SA to a space to be air conditioned, a heat source unit 50 for generating a heat medium such as cold water CW, MCW, LCW or hot water HW, and the heat source unit A heat medium supply system 8 for supplying the heat medium generated at 50 to the air conditioner 1 is configured. In the present embodiment, as the air conditioner 1, the outside air processing air conditioner 1A that processes the outside air OA and supplies it as the air supply SA, or the return air RA returned from the air conditioning target space is processed as the air supply SA The indoor air conditioner 1B etc. to process are provided.

The air conditioner 1 is provided with an air supply passage 6 through which the outside air OA and the return air RA are later supplied as the air supply SA to be supplied to the air conditioning target space by operating the air supply fan 5. The supply air passage 6 is configured of a cold water coil or a hot water coil capable of cooling or heating the supply air SA flowing through the supply air passage 6 by heat exchange with the heat medium supplied from the heat source unit 50. The heat exchange unit 2 is disposed.
Further, as the heat exchange unit 2, the primary heat exchange unit 3 provided on the upstream side in the supply air passage 6 and the secondary heat provided on the downstream side of the primary heat exchange unit 3 in the supply air passage 6 An exchange unit 4 is provided.

The primary heat exchange unit 3 is connected to the primary side heat medium supply passage 14 and the primary side heat medium discharge passage 16, and the heat medium from the primary side heat medium supply passage 14 to the primary heat exchange unit 3 Is supplied, and the heat medium is discharged from the primary heat exchange unit 3 to the primary side heat medium discharge passage 16. On the other hand, the secondary heat exchange unit 4 is connected to the secondary side heat medium supply passage 24 and the secondary side heat medium discharge passage 26, and from the secondary side heat medium supply passage 24 to the secondary heat exchange unit 4. The heat medium is supplied, and the heat medium is discharged from the secondary heat exchange unit 4 to the secondary-side heat medium discharge passage 26.
The primary side heat medium supply passage 14 is provided with an on-off valve 15 capable of blocking the flow of the heat medium, while the secondary side heat medium discharge passage 26 is capable of blocking the flow of the heat medium. A valve 27 is provided. Furthermore, there is provided a cascade connection path 30 connecting the upstream side of the on-off valve 27 in the secondary side heat medium discharge path 26 and the downstream side of the on-off valve 15 in the primary side heat medium supply path 14. The passage 30 is provided with an on-off valve 31 capable of blocking the flow of the heat medium.

The heat source unit 50 is configured to be capable of generating a plurality of types of heat transfer media having different temperatures. For example, as shown in FIG. 1, for example, 13 ° C. medium temperature cold water MCW and 7 ° C. low temperature cold water LCW can be simultaneously generated. Further, as shown in FIGS. 2 and 3, for example, cold water CW of 10 ° C. can be generated, or as shown in FIG. 4, hot water HW of 45 ° C. and cold water CW of, for example, 13 ° C. can be simultaneously generated.
Such a heat source unit 50 is constituted by a heat source unit group consisting of a plurality of heat source units capable of generating heat mediums having different temperatures, and the heat source units are operated appropriately to operate the heat source units of desired temperatures. It can be configured to gain.

The heat medium supply system 8 is connected to the heat source unit 50 via the first header 51 and is connected to the first heat medium supply passage 10 communicating with the primary side heat medium supply passage 14, and to the heat source unit 50. A second heat medium supply passage 20 connected to the second header 52 and communicating with the secondary side heat medium supply passage 24 is separately provided. The first heat medium supply passage 10 is provided with an on-off valve 12 capable of blocking the flow of the heat medium and a flow control valve 13 capable of adjusting the flow rate of the heat medium, while the second heat medium supply The passage 20 is provided with an on-off valve 22 capable of blocking the flow of the heat medium and a flow control valve 23 capable of adjusting the flow rate of the heat medium.
Furthermore, a connection path 40 is provided for connecting the connection portion of the first heat medium supply path 10 to the primary side heat medium supply path 14 and the connection portion of the second heat medium supply path 20 to the secondary side heat medium supply path 24. It is done. The connection path 40 is provided with an on-off valve 41 capable of blocking the flow of the heat medium.

  In the heat medium supply system 8 configured as described above, the parallel supply mode in which the supply state of the heat medium from the heat source unit 50 to the primary heat exchange unit 3 and the secondary heat exchange unit 4 is described below; It is configured to be switchable between the system supply mode and the cascade 1 system supply mode.

(Parallel supply mode)
In the parallel supply mode, for example, as shown in FIGS. 1 and 4, the primary heat exchange unit 3 and the secondary heat exchange unit 4 are connected in parallel to the heat medium supply system 8 and Two kinds of heat medium such as medium-temperature cold water MCW and low-temperature cold water LCW or hot water HW and cold water CW, which have different temperatures, are generated, and these two types of heat medium are divided into primary heat exchange section 3 and secondary heat by different systems. It is set as the mode supplied to each of the exchange part 4.
In the parallel supply mode, the on-off valve 12 is opened and the heat medium supplied from the heat source unit 50 flows through the first heat medium supply passage 10, and the on-off valve 22 is opened and the second heat medium supply passage is opened. At 20, the heat medium supplied from the heat source unit 50 is made to flow. In this state, the open / close valves 15 and 27 are opened, the open / close valves 31 and 41 are closed, and the heat medium supplied from the first heat medium supply passage 10 is transferred to the primary side heat medium supply passage 14. The heat medium supplied from the second heat medium supply passage 20 is supplied to the secondary heat exchange unit 4 via the secondary side heat medium supply passage 24 while being supplied to the primary heat exchange unit 3 via the second heat medium supply passage 20. The heat medium discharged after passing through each of the primary heat exchange unit 3 and the secondary heat exchange unit 4 is the heat medium discharge passage 16 of the primary side and the heat medium discharge passage 26 of the secondary side. Is returned to the heat source unit 50 via the

(Cascade 2 system supply mode)
For example, as shown in FIG. 2, in the cascade two-system supply mode, the primary heat exchange unit 3 and the secondary heat exchange unit 4 are connected in series to the heat medium supply system 8, and In this mode, one heat medium such as CW is generated, and the one heat medium is sequentially supplied to the secondary heat exchange unit 4 and the primary heat exchange unit 3 in two systems.
In the cascade two-system supply mode, the on-off valve 12 is opened and the heat medium supplied from the heat source unit 50 flows through the first heat medium supply passage 10, and the on-off valve 22 is opened on the second heat The heat medium supplied from the heat source unit 50 is allowed to flow through the medium supply passage 20. In this state, the on-off valves 15 and 27 are closed and the on-off valves 31 and 41 are opened, and the water is supplied from the two cooling water systems of the first heat medium supply passage 10 and the second heat medium supply passage 20 The heat medium is supplied to the secondary heat exchange unit 4 through the connection passage 40 and the secondary side heat medium supply passage 24, and the heat discharged from the secondary heat exchange unit 4 to the secondary side heat medium discharge passage 26. The medium is supplied to the primary heat exchange unit 3 via the cascade connection path 30 and the primary-side heat medium supply path 14. Then, the heat medium discharged after sequentially flowing through the secondary heat exchange unit 4 and the primary heat exchange unit 3 is returned to the heat source unit 50 via the primary side heat medium discharge passage 16.

(Cascade 1 system supply mode)
For example, as shown in FIG. 3, in the cascade one-system supply mode, the primary heat exchange unit 3 and the secondary heat exchange unit 4 are connected in series to the heat medium supply system 8 and 1 in the heat source unit 50. The heat medium of a kind is generated, and it is considered as a mode which supplies one kind of heat medium to secondary heat exchange part 4 and primary heat exchange part 3 one by one in order.
In the above-described cascade one-system supply mode, the on-off valve 22 is opened while the on-off valve 22 is opened while the supply of the heat medium from the heat source unit 50 to the first heat medium supply passage 10 is stopped. The heat medium supplied from the heat source unit 50 is allowed to flow through the medium supply passage 20. In this state, the on-off valves 15 and 27 are closed and the on-off valves 31 and 41 are opened, and the heat medium supplied from a single cold water system of the second heat medium supply passage 20 is The heat medium supplied to the secondary heat exchange unit 4 via the heat medium supply passage 24 and discharged from the secondary heat exchange unit 4 to the secondary side heat medium discharge passage 26 is the cascade connection passage 30 and the primary side. The heat is supplied to the primary heat exchange unit 3 through the heat medium supply passage 14. Then, the heat medium discharged after sequentially flowing through the secondary heat exchange unit 4 and the primary heat exchange unit 3 is returned to the heat source unit 50 via the primary side heat medium discharge passage 16.

In the switching between the parallel supply mode and the cascade two-system supply mode, the on-off valve 15 and the on-off valve 41 exchange the connection destination of the first heat medium supply passage 10 with the primary heat exchange unit 3 and the secondary heat exchange. It functions as a connection destination switching unit that can be switched with the unit 4. That is, the on-off valve 15 and the on-off valve 41 are selectively opened to switch the side to be in the open state, and the connection destination of the first heat medium supply path 10, in other words, the first heat medium supply path The supply destination of the heat medium from 10 can be switched between the primary heat exchange unit 3 and the secondary heat exchange unit 4.
Specifically, as in the parallel supply mode (see FIGS. 1 and 4), when the on-off valve 15 is opened and the on-off valve 41 is closed, the connection destination of the first heat medium supply passage 10 is Switches to the primary heat exchange unit 3 and the heat medium is supplied to the primary heat exchange unit 3 through the first heat medium supply passage 10, and the second heat medium to the secondary heat exchange unit 4 The heat medium is supplied via the supply passage 20. On the other hand, if the on-off valve 15 is closed and the on-off valve 41 is opened as in the cascade two-system supply mode (see FIG. 2), the connection destination of the first heat medium supply passage 10 is secondary heat. It switches to the exchange unit 4, and the heat medium can be supplied to the secondary heat exchange unit 4 through both the first heat medium supply passage 10 and the second heat medium supply passage 20.
In switching between the cascade two-system supply mode and the cascade one-system supply mode, the on-off valve 12 and the on-off valve 22 supply the heat medium from the first heat medium supply passage 10 or the second heat medium supply passage 20. Function as a means to shut off the Then, in the form of switching the open / close states of the on-off valves 12 and 22 functioning as these shutoff means, the number of chilled water systems supplying the heat medium to the secondary heat exchange unit 4 is switched between 1 system and 2 systems. be able to.

  The air conditioning system is provided with a control unit 60 that controls the operation. In the summer season, the middle season, etc., the control unit 60 performs latent air separation air conditioning according to the cooling load detected by the temperature and humidity of the air conditioning target space and the temperature and humidity of the returned air RA and the like when performing the cooling operation. The operation and the large temperature difference air conditioning operation are alternatively performed. Further, in winter and the like, the control unit 60 performs simultaneous cooling and heating operation for appropriately performing cooling and heating in each air conditioner 1. The details of the various operations performed by the control unit 60 will be described below.

[Latent micro air separation operation]
The control unit 60 executes the latent-microbe separation air-conditioning operation shown in FIG. 1 at the time of high cooling load such as summer having a high cooling load. In this latent microscopic separation air conditioning operation, medium temperature cold water MCW of 13 ° C. and low temperature cold water LCW of 7 ° C., for example, are separately generated in the heat source unit 50, and the supply state of the heat medium in the heat medium supply system 8 is described above. The mode is switched to the parallel supply mode, and medium temperature cold water MCW is supplied from the heat source unit 50 to the primary heat exchange unit 3 and low temperature cold water LCW is supplied from the heat source unit 50 to the secondary heat exchange unit 4.
Then, in the air conditioner 1, at the primary heat exchange unit 3, the air supply SA, which is relatively high temperature outside air OA and return air RA, does not fall below the dew point by heat exchange with, for example, 13 ° C. medium temperature cold water MCW. The sensible heat treatment is performed in the form of being cooled. On the other hand, in the secondary heat exchange unit 4, the latent heat in the form in which the air supply SA cooled to a certain extent as the primary heat exchange unit 3 is cooled to a temperature lower than the dew point by heat exchange with the low temperature cold water LCW of 7 ° C, for example Processing is performed. Therefore, by executing such latent-microbe separation air-conditioning operation at a high cooling load, the amount of low-temperature cold water LCW that requires a large amount of energy in the heat source unit 50 is reduced, and high efficiency can be achieved.

Large temperature difference air conditioning operation
The control unit 60 executes the large temperature difference air conditioning operation shown in FIGS. 2 and 3 during low cooling load such as an intermediate period in which the cooling load is lower than the high cooling load described above. In this large temperature difference air conditioning operation, for example, cold water CW of 10 ° C. is generated in the heat source unit 50 and the cold water CW is supplied from the heat source unit 50 to the secondary heat exchange unit 4 and from the secondary heat exchange unit 4 The discharged cold water CW of, for example, 15 ° C. is supplied to the primary heat exchange unit 3.
As a result, the difference between the temperature of the return cold water CW and the temperature of the return cold water CW in the heat source unit 50 is maintained at a large value. That is, in this large temperature difference air conditioning operation, in the primary heat exchange unit 3, the relatively high temperature air supply SA, which is the outside air OA or the return air RA, is discharged from the secondary heat exchange unit 4 to a certain extent of 15 ° C, for example. It is cooled without waste by heat exchange with low temperature cold water CW. On the other hand, in the secondary heat exchange unit 4, the air supply SA cooled to a certain extent as the primary heat exchange unit 3 is cooled by the relatively low temperature cold water CW of 10 ° C. supplied from the heat source unit 50. Therefore, cold water CW is supplied to the primary heat exchange unit 3 and the secondary heat exchange unit 4 by a common supply pump (not shown) by executing such a large temperature difference air conditioning operation at a low cooling load. However, in the heat source unit 50, the difference between the return temperature and the temperature is maintained to be large, and high efficiency can be achieved.

Furthermore, in the large temperature difference air conditioning operation, the control unit 60 switches the open / close state of the on-off valve 12 and the on-off valve 22 that function as a shutoff unit based on the cooling load. A cold water system number control is executed which switches and controls the number of cold water systems supplying CW between 1 system and 2 systems.
Specifically, when the cooling load is relatively high in the large temperature difference air conditioning operation, as shown in FIG. 2, the control unit 60 cascades the supply state of the cold water CW in the heat medium supply system 8 as shown in FIG. By switching to the two-system supply mode, the cold water CW is supplied to the secondary heat exchange unit 4 from the two cold water systems of the first heat medium supply passage 10 and the second heat medium supply passage 20. On the other hand, when the cooling load is relatively low in the large temperature difference air conditioning operation, as shown in FIG. 3, the control unit 60 supplies the cascade 1 system of the supply state of the cold water CW in the heat medium supply system 8 as described above. By switching to the mode, the cold water CW is supplied from the single cold water system of the second heat medium supply passage 20 to the secondary heat exchange unit 4.
By performing such cold water system number control, in the large temperature difference air conditioning operation performed at the time of low cooling load, even when the cooling load is further reduced, the supply amount of cold water CW can be sufficiently reduced. . Therefore, in the heat source unit 50, the difference between the return temperature and the temperature is maintained to be large, and high efficiency can be achieved.

Simultaneous operation of heating and cooling
The control unit 60 executes the simultaneous heating and cooling operation shown in FIG. 4 in winter and the like. In this simultaneous heating and heating operation, for example, a hot water HW of 45 ° C. and a cold water CW of 13 ° C., for example, are separately generated in the heat source unit 50. Then, the supply state of the heat medium in the heat medium supply system 8 is switched to the above-described parallel supply mode, and the hot water HW can be supplied to the primary heat exchange unit 3 from the heat source unit 50 The cold water CW can be supplied from the heat source unit 50 to the next heat exchange unit 4.
Then, for example, in the outside air processing air conditioner 1A, the on-off valve 12 is opened and the primary heat exchange unit 3 is opened while the supply of cold water CW to the secondary heat exchange unit 4 is stopped with the on-off valve 22 closed. In the primary heat exchange section 3, the outside air OA, which is relatively low temperature in winter, is heated by heat exchange with, for example, the 45.degree. C. warm water HW by flowing the hot water HW, and the air after heating is heated. It is possible to execute a heating operation for supplying SA to the air conditioning target space.
Further, for example, in the indoor air conditioner 1B, the on-off valve 22 is opened and the secondary heat exchange unit 4 is opened while the supply of hot water HW to the primary heat exchange unit 3 is stopped with the on-off valve 12 closed. By letting cold water CW flow, in the secondary heat exchange unit 4, relatively warm return air RA is cooled by heat exchange with, for example, 13 ° C. cold water CW, and the air supply SA after cooling is air-conditioned It is possible to execute a cooling operation to supply the target space.
In this embodiment, the heating operation is performed in the outside air processing air conditioner 1A, and the cooling operation is performed in the indoor air conditioner 1B. However, any of the heating operation and the cooling operation is performed in each air conditioner 1 It can be set appropriately.

[Another embodiment]
Another embodiment of the present invention will be described. In addition, the configuration of each embodiment described below is not limited to being individually applied, and may be applied in combination with the configuration of the other embodiments.

(1) In the above embodiment, in the large temperature difference air conditioning operation, depending on the time of the cooling load, the supply state of the cold water CW in the heat medium supply system 8 is cascade 2 system supply mode (see FIG. 2) and cascade 1 system supply mode The number of chilled water systems for supplying the chilled water CW to the secondary heat exchange unit 4 is switched between one system and two systems in a mode of switching by (see FIG. 3), but the number of cold water systems May be configured to be switched in three or more systems. Moreover, in the large temperature difference air conditioning operation, regardless of the cooling load, for example, the supply state of the cold water CW in the heat medium supply system 8 is in the cascade 2 system supply mode (see FIG. 2) or the cascade 1 system supply mode (see FIG. 3) The number of chilled water systems for supplying the chilled water CW to the secondary heat exchange unit 4 may be fixed to one system, two systems or more in a fixed form.

(2) In the above embodiment, in the large temperature difference air conditioning operation, the cooling water supply condition in the heat medium supply system 8 is set to the cascade 1 system supply mode (see FIG. 3), and the cooling water is supplied to the secondary heat exchange unit 4. In the case where the number of cold water systems supplying CW is switched to one system, the cold water CW is supplied from the heat source unit 50 to the secondary heat exchange unit 4 through the second heat medium supply passage 20, but The cold water CW may be supplied from the heat source unit 50 to the secondary heat exchange unit 4 through the heat medium supply path 10.

2 heat exchange unit 3 primary heat exchange unit 4 secondary heat exchange unit 6 air supply air passage 10 first heat medium supply passage 12 on-off valve (cut-off means)
15 On-off valve (connection destination switching means)
20 second heat medium supply passage 22 on-off valve (cut-off means)
41 On-off valve (connection destination switching means)
50 heat source unit 60 control unit CW cold water LCW low temperature cold water MCW medium temperature cold water SA air supply

Claims (3)

An air flow path through which the air flows,
A heat source unit for producing cold water,
A heat exchange unit capable of cooling the charge air flowing through the supply air passage by heat exchange with cold water supplied from the heat source unit;
A primary heat exchange portion provided on the upstream side of the air supply path as the heat exchange portion, and a secondary heat exchange portion provided on the downstream side of the primary heat exchange portion in the air supply path; Equipped with
The heat source unit is configured to be able to separately generate low temperature cold water and medium temperature cold water having a temperature higher than the low temperature cold water, respectively.
At the time of high cooling load with high cooling load, the latent heat is supplied from the heat source to the primary heat exchange section from the heat source section, and the low temperature cold water is supplied from the heat source section to the secondary heat exchange section. During the low cooling load, in which the sensible separation air conditioning operation is performed and the cooling load is lower than the high cooling load, the cold water is supplied from the heat source unit to the secondary heat exchange unit and the secondary heat exchange unit An air conditioning system comprising: a control unit that executes a large temperature difference air conditioning operation that supplies cold water discharged from the air to the primary heat exchange unit. A first heat medium supply path through which the medium-temperature cold water is supplied from the heat source unit, and a low-temperature cold water and the medium-temperature cold water are alternatively supplied from the heat source unit and connected to the secondary heat exchange unit And a heat medium supply path,
A connection destination switching unit capable of switching the connection destination of the first heat medium supply path between the primary heat exchange unit and the secondary heat exchange unit;
The control unit switches the connection destination of the first heat medium supply passage to the primary heat exchange unit in the latent microscopic separation air conditioning operation, and the first heat medium supply passage with respect to the primary heat exchange unit And the low-temperature cold water to the secondary heat exchange unit via the second heat medium supply passage, and the first heat medium supply in the large temperature difference air conditioning operation. The connection destination of the passage is switched to the secondary heat exchange unit, and the cold water can be supplied to the secondary heat exchange unit via both the first heat medium supply passage and the second heat medium supply passage. The air conditioning system according to claim 1. A shutoff unit capable of shutting off the supply of cold water from the first heat medium supply passage or the second heat medium supply passage;
The number of chilled water systems in which the control unit controls the number of chilled water systems that supply chilled water to the secondary heat exchange unit in a mode that switches the state of the shutoff unit based on the cooling load in the large temperature difference air conditioning operation The air conditioning system according to claim 2, which executes control.

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