air conditioning system

Abstract

To improve the comfort of a target space conditioned by an air conditioning system. A controller (60) of an air conditioning system (10) performs a first control action when a load index is lower than a reference value, and performs a second control action when the load index is higher than the reference value. The load index correlates with the air conditioning load of a target space (70). The first control action is an action of maintaining the blowout flow rate at a first flow rate and adjusting the blowout temperature so that the temperature of the target space (70) becomes a set temperature. The second control action is an action of maintaining the blowout temperature at the first temperature and adjusting the blowout flow rate so that the temperature of the target space (70) becomes a set temperature.

Description

[Technical Field]

[0001] The present disclosure relates to air conditioning systems. [Background technology]

[0002] Air conditioning systems that form temperature stratification in a target space are known. The displacement ventilation system disclosed in Patent Document 1 is one type of such air conditioning system.

[0003] The above-described air conditioning system supplies cooled air to the lower part of the target space. As a result, a layer of relatively low temperature air is formed in the lower part of the target space where people are present, and a layer of relatively high temperature air is formed in the upper part of the target space where people are not present. The air conditioning system draws air from the upper part of the target space and expels some or all of the drawn air outdoors. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-196978 Summary of the Invention [Problem to be solved by the invention]

[0005] Generally, air conditioning systems that create thermal stratification maintain a constant flow rate of air supplied to a target space and control the temperature of the air supplied to the target space according to the cooling load. Therefore, when the cooling load is high, the temperature of the air blown into the target space by the air conditioning system becomes too low, causing a large temperature difference between the bottom and top of the target space, which can cause discomfort to people in the target space.

[0006] An object of the present disclosure is to improve the comfort of a target space that is air-conditioned by an air-conditioning system that forms thermal stratification. [Means for solving the problem]

[0007] A first aspect of the present disclosure is an air conditioning system (10) that includes a processing unit (20) that draws in air and adjusts its temperature, and that blows the temperature-adjusted air into a target space (70) to form a temperature stratification in the target space (70), and that includes a controller (60) that performs a first control action when a load index that correlates with an air conditioning load of the target space (70) is lower than a reference value, and that performs a second control action when the load index is higher than the reference value, and The flow rate of air that the air conditioning system (10) blows into the target space (70) is the blow-out flow rate, the temperature of the air that the air conditioning system (10) blows into the target space (70) is the blow-out temperature, the first control action is an action of maintaining the blow-out flow rate at a first flow rate and adjusting the blow-out temperature so that the temperature of the target space (70) becomes a set temperature, and the second control action is an action of maintaining the blow-out temperature at the first temperature and adjusting the blow-out flow rate so that the temperature of the target space (70) becomes a set temperature.

[0008] A second aspect of the present disclosure is an air conditioning system (10) that includes a processing unit (20) that sucks in air and adjusts its temperature, and that blows the temperature-adjusted air into a target space (70) to form temperature stratification in the target space (70), and that includes a controller (60) that performs a first control action when a load index that correlates with an air conditioning load of the target space (70) is lower than a reference value, and that performs a second control action when the load index is higher than the reference value, and that the air conditioning system (10) controls the temperature of the target space (70). The flow rate of air blown out into the space (70) is the blowing flow rate, and the temperature of the air blown out by the air conditioning system (10) into the target space (70) is the blowing temperature, the first control operation is an operation of maintaining the blowing flow rate at a first flow rate and adjusting the blowing temperature so that the temperature of the target space (70) becomes a set temperature, and the second control operation is an operation of maintaining the blowing flow rate at a second flow rate greater than the first flow rate and adjusting the blowing temperature so that the temperature of the target space (70) becomes a set temperature.

[0009] In each of the first and second aspects, the controller (60) performs a first control action when the load index is lower than a reference value, and performs a second control action when the load index is lower than the reference value, thereby maintaining comfort in the target space (70) both when the air conditioning load in the target space (70) is relatively low and when it is relatively high.

[0010] A third aspect of the present disclosure is the first or second aspect, further comprising a blow-out unit (32) that supplies the air temperature-adjusted by the processing unit (20) to a lower part of the target space (70), and a suction unit (31) that sucks air from an upper part of the target space (70).

[0011] In the third aspect, the blow-out unit (32) supplies the air whose temperature has been adjusted by the treatment unit (20) to a lower part of the target space (70). In the target space (70) where thermal stratification is formed, the air temperature in the upper part of the target space (70) is higher than the air temperature in the lower part of the target space (70). The suction unit (31) draws air of a relatively high temperature from the upper part of the target space (70).

[0012] A fourth aspect of the present disclosure is the third aspect, wherein the blow-out unit (32) is installed in an upper part of the target space (70), and supplies the air temperature-adjusted by the processing unit (20) to a lower part of the target space (70) by blowing the air toward a floor of the target space (70).

[0013] In the fourth aspect, the blow-out unit (32) installed in the upper part of the target space (70) blows air toward the floor of the target space (70). As a result, the air whose temperature has been adjusted by the treatment unit (20) is supplied to the lower part of the target space (70).

[0014] A fifth aspect of the present disclosure is any one of the first to third aspects, wherein the load index is a difference between the temperature of the target space and the blow-out temperature.

[0015] In the fifth aspect, the controller (60) uses the difference between the "temperature of the target space (70)" and the "discharge temperature" as the load index.

[0016] A sixth aspect of the present disclosure is the third or fourth aspect, wherein the load index is a difference between the temperature of the air sucked by the suction unit (31) from the target space (70) and the blowout temperature.

[0017] In the sixth aspect, the controller (60) uses the difference between the "temperature of the air sucked by the suction unit (31) from the target space (70)" and the "blowout temperature" as the load index. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a diagram showing a schematic configuration of an air conditioning system according to the first embodiment. [Figure 2] FIG. 2 is a diagram showing a first control operation and a second control operation performed by the controller of the first embodiment. [Figure 3] FIG. 3 is a flowchart showing the control operation performed by the controller of the first embodiment when the processing unit is performing the cooling operation. [Figure 4] FIG. 4 is a flowchart showing the control operation performed by the controller of the first embodiment when the processing unit is performing the heating operation. [Figure 5] FIG. 5 is a diagram showing a first control operation and a second control operation performed by the controller of the second embodiment. [Figure 6] FIG. 6 is a flowchart showing the control operation performed by the controller of the second embodiment when the processing unit is performing the cooling operation. [Figure 7] FIG. 7 is a flowchart showing the control operation performed by the controller of the second embodiment when the processing unit is performing the heating operation. [Figure 8] FIG. 8 is a diagram showing a schematic configuration of an air conditioning system according to a first modified example of another embodiment. [Figure 9] FIG. 9 is a diagram showing a schematic configuration of an air conditioning system according to a second modified example of another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0019] First Embodiment A first embodiment will be described below. This embodiment is an air conditioning system (10) that conditions the air of a target space.

[0020] 1, the air conditioning system (10) includes a processing unit (20), an intake unit (31), an exhaust unit (32), a damper unit (33), and a controller (60). The air conditioning system (10) also includes an intake duct (41), an exhaust duct (42), an exhaust duct (43), and an outside air duct (44).

[0021] The number of processing units (20) and suction units (31) shown in Fig. 1 is merely an example. The air conditioning system (10) may include a plurality of suction units (31) and a plurality of blow-out units (32). The installation positions of the suction units (31) and the blow-out units (32) in the target space (70) are not limited to the positions shown in Fig. 1. The number of suction units (31) and the blow-out units (32) included in the air conditioning system (10) and the installation positions of the suction units (31) and the blow-out units (32) in the target space (70) are determined as appropriate depending on the size, shape, and purpose of the target space (70), the positions of items (furniture, etc.) installed in the target space (70), and the like.

[0022] Processing Unit The processing unit (20) includes an air heat exchanger (21) and a blower (22). The air heat exchanger (21) is connected to a chiller device (not shown) via a water pipe (25). Heat transfer water circulates between the air heat exchanger (21) and the chiller device. The air heat exchanger (21) exchanges heat between the heat transfer water cooled or heated in the chiller device and air. The blower (22) draws in and blows out air that has passed through the air heat exchanger (21). A flow rate control valve (26) is provided in the water pipe (25). Changing the opening of the flow rate control valve (26) changes the flow rate of the heat transfer water flowing through the air heat exchanger (21).

[0023] The processing unit (20) adjusts the temperature of the drawn air. Specifically, the processing unit (20) selectively performs a cooling operation and a heating operation. The cooling operation is an operation of cooling the drawn air in the air heat exchanger (21). The heating operation is an operation of heating the drawn air in the air heat exchanger (21).

[0024] <Suction unit> The suction unit (31) is installed on the ceiling of the target space (70). The suction unit (31) draws air through an inlet facing the target space (70). The suction unit (31) also draws air from an upper region (71) of the target space (70). The upper region (71) of the target space (70) will be described later.

[0025] <Intake duct, intake temperature sensor> The suction duct (41) is a duct that connects the processing unit (20) and the suction unit (31). One end of the suction duct (41) is connected to the suction unit (31). The other end of the suction duct (41) is connected to the air inlet of the processing unit (20).

[0026] The intake duct (41) is provided with an intake temperature sensor (51). The intake temperature sensor (51) measures the temperature of air sucked into the intake unit (31) and flowing through the intake duct (41). The measurement value of the intake temperature sensor (51) is substantially equal to the air temperature in the upper region (71) of the target space (70).

[0027] <Exhaust duct, fresh air duct> One end of the exhaust duct (43) is connected to the intake duct (41), and the other end is connected to an outdoor space. One end of the outside air duct (44) is connected to the outdoor space, and the other end is connected to an air inlet of the treatment unit (20).

[0028] <Blow-out unit> The blow-out unit (32) is installed on the ceiling of the target space (70). The blow-out unit (32) blows air from an outlet facing the target space (70) toward the floor of the target space (70). The blow-out unit (32) is installed on the ceiling of the target space (70).

[0029] <Air outlet duct, air outlet temperature sensor> The blow-out duct (42) is a duct that connects the treatment unit (20) and the blow-out unit (32). One end of the blow-out duct (42) is connected to an air outlet of the treatment unit (20). The other end of the blow-out duct (42) is connected to the blow-out unit (32).

[0030] The outlet duct (42) is provided with an outlet temperature sensor (52) that measures the temperature of the air blown out from the processing unit (20) and flowing through the outlet duct (42).

[0031] <Damper unit> The damper unit (33) is provided in the discharge duct (42). The damper unit (33) is a variable air volume (VAV) device. Although not shown, the damper unit (33) includes an air velocity sensor and a damper controller. The air velocity sensor measures the flow velocity of air passing through the damper unit (33). The damper controller controls the opening degree of the damper unit (33) using the measurement value of the air velocity sensor so that the “flow rate of air passing through the damper unit (33)” becomes the “set flow rate received from the controller (60).”

[0032] <Indoor temperature sensor> The air conditioning system (10) includes an indoor temperature sensor (53). The indoor temperature sensor (53) is provided in a lower region (72) of the target space (70). The indoor temperature sensor (53) measures the air temperature in the lower region (72) of the target space (70). The lower region (72) of the target space (70) will be described later.

[0033] Controller The controller (60) includes a microcomputer (61) and a memory device (62). Measurement values ​​of the intake temperature sensor (51), the discharge temperature sensor (52), and the room temperature sensor (53) are input to the controller (60). The microcomputer (61) of the controller (60) executes a program stored in the memory device (62) to adjust the opening of the flow control valve (26) and the set flow rate of the damper unit (33).

[0034] -Air conditioning system operation- The air conditioning system (10) cools the target space (70) and also forms a temperature stratification in the target space (70).

[0035] When the blower (22) of the treatment unit (20) is activated, air in the upper region (71) of the target space (70) is sucked into the suction unit (31). Part of the air sucked into the suction unit (31) is discharged to the outdoors through the exhaust duct (43), and the rest flows into the treatment unit (20). In addition, outside air flows into the treatment unit (20) through the outside air duct (44).

[0036] The air that has flowed into the treatment unit (20) exchanges heat with the heat transfer water while passing through the air heat exchanger (21). The air, whose temperature has been adjusted in the air heat exchanger (21), is blown out from the treatment unit (20) and flows through the blow-out duct (42) into the blow-out unit (32). The blow-out unit (32) blows the incoming air (air whose temperature has been adjusted in the treatment unit (20)) toward the floor of the target space (70). The air blown out from the blow-out unit (32) reaches the vicinity of the floor of the target space (70) and flows and diffuses along the floor of the target space (70).

[0037] The air conditioning system (10) cools the target space (70) by supplying air having a temperature lower than the air temperature of the target space (70) to the target space (70). To this end, the processing unit (20) adjusts the temperature of the drawn air so that the temperature of the air that has passed through the air heat exchanger (21) is lower than the air temperature of the target space (70).

[0038] Meanwhile, the air sucked into the suction unit (31) and the outside air that has passed through the outside air duct (44) flow into the treatment unit (20). Therefore, the temperature of the air flowing into the treatment unit (20) changes depending on the temperature of the outside air.

[0039] For example, in summer when the outdoor air temperature is high, the temperature of the air flowing into the treatment unit (20) is usually higher than the air temperature in the target space (70). In this case, the treatment unit (20) performs a cooling operation. In the cooling operation, the treatment unit (20) exchanges heat between the heat transfer water cooled by the chiller device and the air in the air heat exchanger (21). The treatment unit (20) then blows the air cooled in the air heat exchanger (21) toward the blow-out unit (32).

[0040] In winter, when the outdoor air temperature is low, the temperature of the air flowing into the treatment unit (20) is usually lower than the air temperature of the target space (70). In this case, the treatment unit (20) performs a heating operation. In the heating operation, the treatment unit (20) exchanges heat between the heat transfer water heated by the chiller device and the air in the air heat exchanger (21). The treatment unit (20) then blows the air heated in the air heat exchanger (21) toward the blow-out unit (32).

[0041] -Temperature stratification in the target space- In the target space (70), the air whose temperature has been adjusted in the treatment unit (20) and blown out from the blow-out unit (32) is supplied to the lower part of the target space (70). As described above, the air blown out from the blow-out unit (32) reaches the vicinity of the floor of the target space (70) and flows along the floor, where it is diffused. As a result, a lower region (72) with a relatively low temperature is formed in the lower part of the target space (70). The lower region (72) is a space where people who use the target space (70) are present. Therefore, in the target space (70), the temperature of the lower region (72) where people are present can be efficiently maintained within a comfortable range.

[0042] In the target space 70, air heated by heat generated by people and equipment in the lower region 72 moves upward and stagnates in the upper part of the target space 70. As a result, an upper region 71 with a relatively high temperature is formed in the upper part of the target space 70. The air conditioning system 10 discharges a portion of the air drawn in from the upper region 71 with a relatively high temperature to the outdoors, and adjusts the temperature of the remainder in the treatment unit 20.

[0043] Furthermore, pollutants such as carbon dioxide and odorous substances generated in the lower region (72) move upward in the target space (70) along with the rising air and remain in the upper region (71). The air conditioning system (10) discharges a portion of the air drawn in from the upper region (71), where the concentration of pollutants is relatively high, to the outdoors. This allows the pollutants in the target space (70) to be efficiently discharged to the outside of the target space (70).

[0044] The air conditioning system (10) of this embodiment supplies temperature-controlled air to the lower region (72) of the target space (70), while discharging a portion of the air drawn in from the upper region (71) of the target space (70) to the outdoors and controlling the temperature of the remainder in the treatment unit (20). Therefore, by using the air conditioning system (10) of this embodiment, it is possible to efficiently cool and ventilate the target space (70).

[0045] -Control operation performed by the controller (overview)- As shown in Fig. 2, the controller (60) selectively performs a first control action and a second control action. The controller (60) performs the first control action when the load index L is equal to or less than a reference value Lr, and performs the second control action when the load index L is greater than the reference value Lr. Alternatively, the controller (60) may perform the first control action when the load index is less than the reference value Lr, and the second control action when the load index is equal to or greater than the reference value Lr. The reference value Lr is, for example, 6°C.

[0046] <Load index> The load index L in this embodiment is the difference between the “temperature of the target space (70)” and the “discharge temperature.” The controller (60) in this embodiment uses the difference between the measurement value θim of the room temperature sensor (53) and the measurement value θsm of the discharge temperature sensor (52) as the load index L (L=θim−θsm).

[0047] The indoor temperature sensor 53 measures the air temperature in the lower region 72 of the target space 70. Therefore, the measurement value θim of the indoor temperature sensor 53 is the actual measurement value of the “temperature of the target space 70”.

[0048] The "discharge temperature" is the temperature of air discharged from the air conditioning system (10) into the target space (70). The discharge temperature sensor (52) measures the temperature of air discharged from the processing unit (20) and flowing through the discharge duct (42). The "temperature of air flowing through the discharge duct (42)" is substantially equal to the "temperature of air discharged from the discharge unit (32) into the target space (70)." Therefore, the measurement value θsm of the discharge temperature sensor (52) is the actual measurement value of the "discharge temperature."

[0049] As the temperature of the target space (70) increases, the cooling load of the target space (70) increases. Therefore, as the cooling load of the target space (70) increases, the difference between the "temperature of the target space (70)" and the "blowout temperature" increases. In this way, the difference between the "temperature of the target space (70)" and the "blowout temperature" correlates with the cooling load of the target space (70). Furthermore, the cooling load is a type of air conditioning load. Therefore, the difference (θim - θsm) between the measurement value θim of the indoor temperature sensor (53) and the measurement value θsm of the blowout temperature sensor (52) is a load index L that correlates with the air conditioning load of the target space (70).

[0050] <First control action> As shown in FIG. 2, the first control operation is an operation for maintaining the blowout flow rate at a first flow rate and adjusting the blowout temperature so that the temperature of the target space (70) becomes a set temperature.

[0051] The "blowout flow rate" is the flow rate of air blown out from the air conditioning system (10) into the target space (70). In the air conditioning system (10) of this embodiment, the air blown out from the processing unit (20) and flowing through the blowout duct (42) passes through the damper unit (33) and is then blown out from the blowout unit (32) into the target space. Therefore, the "blowout flow rate" is substantially equal to the "flow rate of air passing through the damper unit (33)."

[0052] In the first control action, the controller (60) controls the opening of the flow rate control valve (26) so that the measured value θim of the room temperature sensor (53) becomes the room set temperature θi. In the first control action, the controller (60) controls the opening of the flow rate control valve (26) so that the blow-out temperature decreases as the load index L increases.

[0053] When the processing unit (20) is performing a cooling operation, the controller (60) increases the degree of opening of the flow rate control valve (26) as the load index L increases. As the degree of opening of the flow rate control valve (26) increases, the flow rate of the heat transfer water (chilled water) flowing through the air heat exchanger (21) increases, and accordingly, the temperature of the air that has passed through the air heat exchanger (21) decreases. As a result, as the load index L increases, the discharge temperature decreases.

[0054] When the processing unit (20) is performing a heating operation, the controller (60) reduces the opening of the flow rate control valve (26) as the load index L increases. As the opening of the flow rate control valve (26) decreases, the flow rate of the heat transfer water (hot water) flowing through the air heat exchanger (21) decreases, and accordingly, the temperature of the air that has passed through the air heat exchanger (21) decreases. As a result, as the load index L increases, the blown-out temperature decreases.

[0055] In the first control action, the controller (60) maintains the set flow rate to be sent to the damper unit (33) at the first flow rate, so that the flow rate of air blown out from the blow-out unit (32) to the target space (70) (blow-out flow rate) is maintained at the first flow rate.

[0056] <Second control action> As shown in FIG. 2, the second control operation is an operation for maintaining the blowout temperature at the first temperature and adjusting the blowout flow rate so that the temperature of the target space (70) becomes the set temperature.

[0057] In the second control operation, the controller (60) adjusts the set flow rate to be transmitted to the damper unit (33) so that the measured value θim of the room temperature sensor (53) becomes the room set temperature θi. The controller (60) increases the set flow rate as the load index L increases. As the set flow rate increases, the flow rate of air passing through the damper unit (33) increases, and as a result, the flow rate of air blown out from the blowout unit (32) to the target space (70) (blowout flow rate) increases.

[0058] In the second control operation, the controller (60) controls the opening of the flow rate adjustment valve (26) so that the blow-out temperature is maintained at the first temperature. Specifically, the controller (60) controls the opening of the flow rate adjustment valve (26) so that the measurement value θsm of the blow-out temperature sensor (52) becomes the first temperature.

[0059] When the processing unit (20) is performing a cooling operation, the controller (60) increases the opening of the flow rate control valve (26) when the measurement value θsm of the blow-out temperature sensor (52) is higher than the first temperature, and decreases the opening of the flow rate control valve (26) when the measurement value θsm of the blow-out temperature sensor (52) is lower than the first temperature.

[0060] On the other hand, when the processing unit (20) is performing a heating operation, the controller (60) reduces the opening of the flow rate control valve (26) when the measurement value θsm of the blow-out temperature sensor (52) is higher than the first temperature, and increases the opening of the flow rate control valve (26) when the measurement value θsm of the blow-out temperature sensor (52) is lower than the first temperature.

[0061] -Control operation performed by the controller (details, during cooling operation)- The control operation performed by the controller (60) when the processing unit (20) is performing the cooling operation will be described with reference to the flowchart of Fig. 3. In Fig. 3, the processes from step ST11 to step ST15 are the first control operation, and the processes from step ST21 to step ST25 are the second control operation.

[0062] <Step ST11> In the process of step ST11, the controller (60) sets the set flow rate to be sent to the damper unit (33) to a first flow rate. The damper unit (33) controls the opening degree of the damper unit (33) so that the flow rate of air passing through the damper unit (33) becomes the first flow rate. As a result, the flow rate of air blown out from the blow-out unit (32) to the target space (70) is maintained at the first flow rate. After completing the process of step ST11, the controller (60) performs the process of step ST12.

[0063] <Step ST12> In the process of step ST12, the controller (60) acquires the measured value θim of the room temperature sensor (53). Then, the controller (60) determines whether or not the condition that "the measured value θim of the room temperature sensor (53) is higher than the set value θi of the room temperature (θi<θim)" is met. If this condition is met, the controller (60) performs the process of step ST13. On the other hand, if this condition is not met, the controller (60) performs the process of step ST14.

[0064] <Step ST13> In the process of step ST13, the controller (60) increases the opening of the flow rate control valve (26) and then waits for a predetermined time (e.g., 10 minutes). When the opening of the flow rate control valve (26) is increased, the flow rate of the heat transfer water (chilled water) flowing through the air heat exchanger (21) increases, and the temperature of the air blown out by the blow-out unit (32) into the target space (70) decreases. After completing the process of step ST13, the controller (60) performs the process of step ST15.

[0065] <Step ST14> In the process of step ST14, the controller (60) reduces the opening of the flow rate control valve (26) and then waits for a predetermined time (e.g., 10 minutes). When the opening of the flow rate control valve (26) is reduced, the flow rate of the heat transfer water (chilled water) flowing through the air heat exchanger (21) decreases, and the temperature of the air blown out by the blow-out unit (32) into the target space (70) increases. After completing the process of step ST14, the controller (60) performs the process of step ST15.

[0066] <Step ST15> In the process of step ST15, the controller (60) determines whether the condition that "the load index L is higher than the reference value Lr" is met. As described above, the load index L in this embodiment is the difference between the measurement value θim of the room temperature sensor (53) and the measurement value θsm of the discharge temperature sensor (52) (L=θim-θsm). This condition is met when the cooling load in the target space (70) is relatively high. Therefore, if this condition is met, the controller (60) performs the process of step ST21. On the other hand, if this condition is not met, the controller (60) performs the process of step ST11 to continue the first control action.

[0067] <Step ST21> In the process of step ST21, the controller (60) acquires the measured value θim of the room temperature sensor (53). Then, the controller (60) determines whether or not the condition that "the measured value θim of the room temperature sensor (53) is higher than the set value θi of the room temperature (θi<θim)" is met. If this condition is met, the controller (60) performs the process of step ST22. On the other hand, if this condition is not met, the controller (60) performs the process of step ST23.

[0068] <Step ST22> In the process of step ST22, the controller (60) increases the set flow rate to be sent to the damper unit (33) and then waits for a predetermined time (e.g., 10 minutes). The opening degree of the damper unit (33) is controlled so that the flow rate of air passing through the damper unit (33) becomes the set flow rate. As a result, the flow rate of air blown out from the blow-out unit (32) into the target space (70) increases. After completing the process of step ST22, the controller (60) performs the process of step ST24.

[0069] <Step ST23> In the process of step ST23, the controller (60) reduces the set flow rate to be sent to the damper unit (33) and then waits for a predetermined time (e.g., 10 minutes). The opening degree of the damper unit (33) is controlled so that the flow rate of air passing through the damper unit (33) becomes the set flow rate. As a result, the flow rate of air blown out from the blow-out unit (32) into the target space (70) decreases. After completing the process of step ST23, the controller (60) performs the process of step ST24.

[0070] <Step ST24> When the flow rate of the air passing through the damper unit (33) changes, the flow rate of the air passing through the air heat exchanger (21) of the processing unit (20) changes accordingly. If the flow rate of the heat transfer water flowing through the air heat exchanger (21) is constant, when the flow rate of the air passing through the air heat exchanger (21) changes, the temperature of the air that has passed through the air heat exchanger (21) changes accordingly.

[0071] Therefore, in the process of step ST24, the controller (60) adjusts the opening of the flow rate adjustment valve (26) so that the measurement value θsm of the discharge temperature sensor (52) is maintained at the first temperature. Specifically, the controller (60) increases the opening of the flow rate adjustment valve (26) when the measurement value θsm is higher than the first temperature, decreases the opening of the flow rate adjustment valve (26) when the measurement value θsm is lower than the first temperature, and maintains the opening of the flow rate adjustment valve (26) when the measurement value θsm is the first temperature. After completing the process of step ST24, the controller (60) performs the process of step ST25.

[0072] <Step ST25> In the process of step ST25, the controller (60) determines whether the condition that "the load index L is equal to or less than (reference value Lr-1.5)" is met. As described above, the load index L in this embodiment is the difference between the measurement value θim of the room temperature sensor (53) and the measurement value θsm of the discharge temperature sensor (52) (L=θim-θsm). This condition is met when the cooling load in the target space (70) is relatively high. If this condition is met, the controller (60) performs the process of step ST21 to continue the second control action. On the other hand, if this condition is not met, it can be determined that the cooling load in the target space (70) is relatively low. If this condition is not met, the controller (60) performs the process of step ST11 to perform the first control action.

[0073] -Control operation performed by the controller (details, during heating operation)- The control operation performed by the controller (60) when the processing unit (20) is performing a heating operation will be described with reference to the flowchart of FIG.

[0074] As shown in Fig. 4, the controller (60) performs the process of step ST13' instead of the process of step ST13 in Fig. 3, performs the process of step ST14' instead of the process of step ST14 in Fig. 3, and performs the process of step ST24' instead of the process of step ST24 in Fig. 3. Here, the processes of step ST13', step ST14', and step ST24' will be described.

[0075] <Step ST13'> In the process of step ST13', the controller (60) reduces the opening of the flow rate control valve (26) and then waits for a predetermined time (e.g., 10 minutes). When the opening of the flow rate control valve (26) is reduced, the flow rate of the heat transfer water (hot water) flowing through the air heat exchanger (21) decreases, and the temperature of the air blown out by the blow-out unit (32) into the target space (70) decreases. After completing the process of step ST13', the controller (60) performs the process of step ST15.

[0076] <Step ST14'> In the process of step ST14', the controller (60) increases the opening of the flow rate control valve (26) and then waits for a predetermined time (e.g., 10 minutes). When the opening of the flow rate control valve (26) is increased, the flow rate of the heat transfer water (hot water) flowing through the air heat exchanger (21) increases, and the temperature of the air blown out by the blow-out unit (32) into the target space (70) increases. After completing the process of step ST14', the controller (60) performs the process of step ST15.

[0077] <Step ST24'> In the process of step ST24', the controller (60) adjusts the opening of the flow rate adjustment valve (26) so that the measurement value θsm of the discharge temperature sensor (52) is maintained at the first temperature. Specifically, the controller (60) reduces the opening of the flow rate adjustment valve (26) when the measurement value θsm is higher than the first temperature, increases the opening of the flow rate adjustment valve (26) when the measurement value θsm is lower than the first temperature, and maintains the opening of the flow rate adjustment valve (26) when the measurement value θsm is the first temperature. After completing the process of step ST24', the controller (60) performs the process of step ST25.

[0078] -Feature (1) of the first embodiment- In the air conditioning system (10) of this embodiment, the controller (60) performs a first control operation when the load index L is lower than a reference value Lr. In the first control operation, the controller (60) maintains the blowout flow rate at a first flow rate and adjusts the blowout temperature so that the temperature of the target space (70) becomes the set temperature.

[0079] When the load index L is lower than the reference value Lr, the cooling load in the target space (70) is relatively small, and the discharge temperature is not too low but is maintained within an appropriate range. Therefore, in the target space (70), the air temperature in the lower area (72) where people are present is maintained within an appropriate range, and the temperature difference between the upper area (71) and the lower area (72) is kept below a predetermined value. Therefore, the comfort level of the target space (70) is maintained at a high level.

[0080] Furthermore, in the air conditioning system (10) of this embodiment, the controller (60) performs a second control action when the load index L is higher than the reference value Lr. In the second control action, the controller (60) maintains the blow-out temperature at the first temperature and adjusts the blow-out flow rate so that the temperature of the target space (70) becomes the set temperature.

[0081] When the load index L is higher than the reference value Lr, the cooling load in the target space (70) is relatively high, but the blown air temperature is maintained at the first temperature. Therefore, even when the cooling load in the target space (70) is relatively high, the blown air temperature does not become too low. Therefore, even when the cooling load in the target space (70) is relatively high, the air temperature in the lower area (72) where people are present is maintained within an appropriate range, and the temperature difference between the upper area (71) and the lower area (72) is kept below a predetermined value. As a result, the comfort level of the target space (70) is maintained at a high level.

[0082] As described above, the air conditioning system (10) of the present embodiment can maintain high comfort in the target space (70) both when the cooling load in the target space (70) is relatively low and when the cooling load is relatively high.

[0083] -Feature (2) of the first embodiment- The air conditioning system (10) of this embodiment causes the air blown downward by the blow-out unit (32) to reach the floor of the target space (70), thereby forming temperature stratification in the target space (70). Therefore, the air conditioning system (10) of this embodiment can efficiently air-condition the target space (70) by forming temperature stratification in the target space (70), while avoiding an increase in the complexity of the building structure or an increase in the number of work steps required to install the air conditioning system (10) in a building.

[0084] -Feature (3) of the first embodiment- Here, if the vertical temperature difference in the target space (70) (specifically, the temperature difference between the upper and lower parts of the target space (70)) exceeds a predetermined upper limit, people in the target space (70) may feel uncomfortable.

[0085] On the other hand, in the air conditioning system (10) of this embodiment, the difference between the “temperature of the target space (70)” and the “blowout temperature” is used as the load index L used by the controller (60) to select between the first control action and the second control action. This load index L correlates with the temperature difference in the vertical direction in the target space (70) (hereinafter referred to as “vertical temperature difference”). As the vertical temperature difference increases, the load index L also increases.

[0086] In the air conditioning system (10) of this embodiment, the load index L when the vertical temperature difference is at the upper limit can be set to a reference value Lr. The controller (60) selects between the first control action and the second control action using the reference value Lr set in this way, thereby making it possible to keep the vertical temperature difference at or below the upper limit. As a result, it is possible to prevent people in the target space (70) from feeling uncomfortable due to the vertical temperature difference, and it is possible to maintain a high level of comfort in the target space (70).

[0087] Second Embodiment A second embodiment will be described. The air conditioning system (10) of this embodiment is the air conditioning system (10) of the first embodiment, except that the damper unit (33) and the controller (60) are changed. Here, the air conditioning system (10) of this embodiment will be described, mainly focusing on the differences from the air conditioning system (10) of the first embodiment.

[0088] -Damper unit- The damper unit (33) of this embodiment is a constant air volume (CAV) control device. Although not shown, the damper unit (33) includes an air velocity sensor and a damper controller. The air velocity sensor measures the flow velocity of air passing through the damper unit (33). The damper controller controls the opening degree of the damper unit (33) using the measurement value of the air velocity sensor so that the "flow rate of air passing through the damper unit (33)" becomes a "preset set flow rate." The "set flow rate" of the damper unit (33) can be changed based on an instruction sent from the controller (60).

[0089] -Controller- The controller (60) of this embodiment includes a microcomputer (61) and a memory device (62), similar to the controller (60) of the first embodiment. The controller (60) of this embodiment controls the opening of the flow rate adjustment valve (26) and instructs the damper unit (33) to change the set flow rate. As will be described later, the controller (60) of this embodiment differs from the controller (60) of the first embodiment in the control operations it performs.

[0090] -Control operation performed by the controller (overview)- 5, the controller (60) selectively performs a first control action and a second control action. Like the controller (60) of the first embodiment, the controller (60) of the present embodiment performs the first control action when the load index L is equal to or less than the reference value Lr, and performs the second control action when the load index L is greater than the reference value Lr. Note that, like the controller (60) of the first embodiment, the controller (60) of the present embodiment may perform the first control action when the load index is less than the reference value Lr, and may perform the second control action when the load index is equal to or greater than the reference value Lr.

[0091] <Load index> The controller (60) of this embodiment, like the controller (60) of the first embodiment, uses the difference between the measurement value θim of the room temperature sensor (53) and the measurement value θsm of the discharge temperature sensor (52) as the load index L (L=θim−θsm).

[0092] <First control action> 5, the first control operation is an operation for maintaining the blow-out flow rate at a first flow rate and adjusting the blow-out temperature so that the temperature of the target space (70) becomes the set temperature. The first control operation performed by the controller (60) of this embodiment is the same as the first control operation performed by the controller (60) of embodiment 1. A description of the first control operation performed by the controller (60) of this embodiment will be omitted.

[0093] <Second control action> 5, the second control operation is an operation of maintaining the blowout flow rate at a second flow rate greater than the first flow rate and adjusting the blowout temperature so that the temperature of the target space (70) becomes the set temperature. The second control operation performed by the controller (60) of this embodiment is different from the second control operation performed by the controller (60) of the first embodiment.

[0094] In the second control operation, the controller (60) of this embodiment transmits an instruction signal to the damper unit (33) to change the set air volume from the first air volume to the second air volume. Upon receiving this instruction signal, the damper unit (33) increases the set air volume from the first air volume to the second air volume. The damper unit (33) then adjusts the opening degree of the damper unit (33) so that the flow rate of air passing through the damper unit (33) becomes the second air volume.

[0095] In the second control action, the controller (60) controls the opening of the flow rate adjustment valve (26) so that the measured value θim of the room temperature sensor (53) becomes equal to the set value θi of the room temperature. In the second control action, the controller (60) controls the opening of the flow rate adjustment valve (26) so that the blow-out temperature decreases as the load index L increases. This action is the same as the action performed by the controller (60) in the first control action.

[0096] When the processing unit (20) is performing a cooling operation, the controller (60) increases the degree of opening of the flow rate control valve (26) as the load index L increases. As the degree of opening of the flow rate control valve (26) increases, the flow rate of the heat transfer water (chilled water) flowing through the air heat exchanger (21) increases, and accordingly, the temperature of the air that has passed through the air heat exchanger (21) decreases. As a result, as the load index L increases, the discharge temperature decreases.

[0097] When the processing unit (20) is performing a heating operation, the controller (60) reduces the opening of the flow rate control valve (26) as the load index L increases. As the opening of the flow rate control valve (26) decreases, the flow rate of the heat transfer water (hot water) flowing through the air heat exchanger (21) decreases, and accordingly, the temperature of the air that has passed through the air heat exchanger (21) decreases. As a result, as the load index L increases, the blown-out temperature decreases.

[0098] -Control operation performed by the controller (details, during cooling operation)- The control operation performed by the controller (60) when the processing unit (20) is performing the cooling operation will be described in detail with reference to the flowchart of Fig. 6. In Fig. 6, the processes from step ST11 to step ST15 are the first control operation, and the processes from step ST31 to step ST35 are the second control operation.

[0099] As described above, the first control action performed by the controller (60) of this embodiment is the same as the first control action performed by the controller (60) of embodiment 1. Therefore, the processes from step ST11 to step ST15 in Fig. 6 are the same as the processes from step ST11 to step ST15 in Fig. 3. Therefore, a description of the processes from step ST11 to step ST15 will be omitted.

[0100] <Step ST31> The condition of step ST15 is met when the cooling load of the target space (70) is relatively high. When this condition is met, the controller (60) performs the process of step ST31 to start the second control action.

[0101] In the process of step ST31, the controller (60) transmits an instruction signal to the damper unit (33) to change the set air volume from the first air volume to the second air volume. Upon receiving this instruction signal, the damper unit (33) adjusts the opening degree of the damper unit (33) so that the flow rate of air passing through the damper unit (33) becomes the second air volume. After completing the process of step ST31, the controller (60) performs the process of step ST32.

[0102] <Step ST32> In the process of step ST32, the controller (60) acquires the measured value θim of the room temperature sensor (53). Then, the controller (60) determines whether or not the condition that "the measured value θim of the room temperature sensor (53) is higher than the set value θi of the room temperature (θi<θim)" is met. If this condition is met, the controller (60) performs the process of step ST33. On the other hand, if this condition is not met, the controller (60) performs the process of step ST34.

[0103] <Step ST33> In the process of step ST33, the controller (60) increases the opening of the flow rate control valve (26) and then waits for a predetermined time (e.g., 10 minutes). When the opening of the flow rate control valve (26) is increased, the flow rate of the heat transfer water (chilled water) flowing through the air heat exchanger (21) increases, and the temperature of the air blown out by the blow-out unit (32) into the target space (70) decreases. After completing the process of step ST33, the controller (60) performs the process of step ST35.

[0104] <Step ST34> In the process of step ST34, the controller (60) reduces the opening of the flow rate control valve (26) and then waits for a predetermined time (e.g., 10 minutes). When the opening of the flow rate control valve (26) is reduced, the flow rate of the heat transfer water (chilled water) flowing through the air heat exchanger (21) decreases, and the temperature of the air blown out by the blow-out unit (32) into the target space (70) increases. After completing the process of step ST34, the controller (60) performs the process of step ST35.

[0105] <Step ST35> In the process of step ST35, the controller (60) determines whether the condition that "the load index L is equal to or less than a predetermined reference value" is met. The reference value in step ST35 is "(Lr-1.5) x (first flow rate / second flow rate)". As described above, Lr is a reference value related to the load index.

[0106] The condition of step ST35 is met when the cooling load of the target space (70) is relatively high. If this condition is met, the controller (60) performs the process of step ST31 to continue the second control action. On the other hand, if this condition is not met, it can be determined that the cooling load of the target space (70) is relatively low. If this condition is not met, the controller (60) performs the process of step ST11 to perform the first control action.

[0107] -Control operation performed by the controller (details, during heating operation)- The control operation performed by the controller (60) when the processing unit (20) is performing a heating operation will be described with reference to the flowchart of FIG.

[0108] As shown in Fig. 7, the controller (60) performs the process of step ST13' instead of the process of step ST13 in Fig. 6, the process of step ST14' instead of the process of step ST14 in Fig. 6, the process of step ST33' instead of the process of step ST33 in Fig. 6, and the process of step ST34' instead of the process of step ST34 in Fig. 6. The process of step ST13' in Fig. 7 is the same as the process of step ST13' in Fig. 4. The process of step ST14' in Fig. 7 is the same as the process of step ST14' in Fig. 4. Here, the processes of step ST33' and step ST34' will be described.

[0109] <Step ST33'> In the process of step ST33', the controller (60) reduces the opening of the flow rate control valve (26) and then waits for a predetermined time (e.g., 10 minutes). When the opening of the flow rate control valve (26) is reduced, the flow rate of the heat transfer water (hot water) flowing through the air heat exchanger (21) decreases, and the temperature of the air blown out by the blow-out unit (32) into the target space (70) decreases. After completing the process of step ST33', the controller (60) performs the process of step ST35.

[0110] <Step ST34'> In the process of step ST34', the controller (60) increases the opening of the flow rate control valve (26) and then waits for a predetermined time (e.g., 10 minutes). When the opening of the flow rate control valve (26) is increased, the flow rate of the heat transfer water (hot water) flowing through the air heat exchanger (21) increases, and the temperature of the air blown out by the blow-out unit (32) into the target space (70) increases. After completing the process of step ST34', the controller (60) performs the process of step ST35.

[0111] -Features of the second embodiment- According to the air conditioning system (10) of this embodiment, similar to the air conditioning system (10) of embodiment 1, the comfort of the target space (70) can be maintained at a high level both when the cooling load of the target space (70) is relatively low and when the cooling load is relatively high.

[0112] Other Embodiments The following modifications may be applied to the air conditioning system (10) of the above embodiment. The following modifications may be combined or substituted as appropriate as long as the functionality of the air conditioning system (10) is not impaired.

[0113] -First Modification- As shown in FIG. 8, in the air conditioning system (10) of the first and second embodiments, the suction duct (41) may be omitted, and one end of the exhaust duct (43) may be connected to the suction unit (31).

[0114] In the air conditioning system (10) of this modified example, the suction temperature sensor (51) is provided in the exhaust duct (43). The suction temperature sensor (51) measures the temperature of air sucked into the suction unit (31) and flowing through the exhaust duct (43). The measurement value of the suction temperature sensor (51) is substantially equal to the air temperature in the upper region (71) of the target space (70).

[0115] In the air conditioning system (10) of this modification, only outdoor air flowing through the outdoor air duct (44) flows into the processing unit (20). Similar to the processing units (20) of the first and second embodiments, the processing unit (20) adjusts the temperature of the incoming air in the air heat exchanger (21) and blows the temperature-adjusted air out through the outlet duct (42).

[0116] -Second modified example- As shown in FIG. 9, the air conditioning system (10) of the first and second embodiments may include an outdoor air-conditioning unit (35).

[0117] The outdoor air conditioner (35) is provided in the outdoor air duct (44) and adjusts the temperature of the outdoor air flowing through the outdoor air duct (44) toward the treatment unit (20).

[0118] The outdoor air-conditioning unit (35) includes an outdoor air heat exchanger (36) and a blower (37). The outdoor air heat exchanger (36), like the air heat exchanger (21) of the processing unit (20), is connected to a chiller device (not shown) via a pipe. Heat transfer water circulates between the outdoor air heat exchanger (36) and the chiller device. The outdoor air heat exchanger (36) exchanges heat between the heat transfer water cooled or heated in the chiller device and air. The blower (37) draws in and blows out air that has passed through the outdoor air heat exchanger (36).

[0119] In the air conditioning system (10) of this modified example, the outdoor air flowing through the outdoor air duct (44) is temperature-adjusted in the outdoor air conditioning unit (35) and then flows into the treatment unit (20). For example, in summer when the outdoor air temperature is high, the outdoor air flowing through the outdoor air duct (44) is cooled in the outdoor air heat exchanger (36) and then flows into the treatment unit (20). In winter when the outdoor air temperature is low, the outdoor air flowing through the outdoor air duct (44) is heated in the outdoor air heat exchanger (36) and then flows into the treatment unit (20).

[0120] -Third Modification- In the air conditioning systems (10) of the first and second embodiments, the load index L used by the controller (60) in the control operation may be the difference between the “temperature of the air sucked by the suction unit (31) from the target space (70)” and the “discharge temperature.” The controller (60) of this modification uses the difference between the measurement value θem of the suction temperature sensor (51) and the measurement value θsm of the discharge temperature sensor (52) as the load index L (L=θem−θsm).

[0121] The “temperature of the air sucked by the suction unit (31) from the target space (70)” is substantially equal to the temperature of the air flowing through the suction duct (41). Therefore, the measurement value θem of the suction temperature sensor (51) is the actual measurement value of the “temperature of the air sucked by the suction unit (31) from the target space (70).”

[0122] The measured value θem of the intake temperature sensor (51) is substantially equal to the air temperature in the upper region (71) of the target space (70). As the air temperature in the upper region (71) of the target space (70) increases, the cooling load of the target space (70) increases. Therefore, as the cooling load of the target space (70) increases, the difference between the "temperature of air sucked from the target space (70) by the intake unit (31)" and the "discharge temperature" increases. In this way, the difference between the "temperature of air sucked from the target space (70) by the intake unit (31)" and the "discharge temperature" correlates with the cooling load of the target space (70). Furthermore, the cooling load is a type of air-conditioning load. Therefore, the difference (θem - θsm) between the measured value θem of the intake temperature sensor (51) and the measured value θsm of the discharge temperature sensor (52) is a load index L that correlates with the air-conditioning load of the target space (70).

[0123] -Fourth Modification- In the air conditioning system (10) of the first and second embodiments, the blow-out unit (32) may be installed near the floor of the target space (70). The blow-out unit (32) of this modification blows out air sent from the processing unit (20) through the blow-out duct (42) from an outlet facing the lower region (72) of the target space (70).

[0124] Although the embodiments and modifications have been described above, it will be understood that various modifications in form and detail are possible without departing from the spirit and scope of the claims. Furthermore, elements of the above embodiments, modifications, and other embodiments may be combined or substituted as appropriate. Furthermore, the terms "first" and "second" in the specification and claims are used to distinguish between terms to which these terms are attached, and do not limit the number or order of those terms. [Industrial Applicability]

[0125] As described above, the present disclosure is useful for air conditioning systems. [Explanation of symbols]

[0126] 10. Air conditioning system 20 Processing Unit 31 Suction unit 32 Air outlet unit 60 Controller 70 Target Space

Claims

1. An air conditioning system (10) comprising a treatment unit (20) that sucks in air and adjusts its temperature, the treatment unit (20) blowing the temperature-adjusted air into a target space (70) to form a temperature stratification in the target space (70), a controller (60) that performs a first control operation when a load index correlated with an air conditioning load of the target space (70) is lower than a reference value, and that performs a second control operation when the load index is higher than the reference value, the flow rate of air blown out from the air conditioning system (10) to the target space (70) is the blowout flow rate; the temperature of the air blown out from the air conditioning system (10) to the target space (70) is the blowout temperature; the first control action is an action of maintaining the blowout flow rate at a first flow rate and adjusting the blowout temperature so that the temperature of the target space (70) becomes a set temperature; The second control operation is an operation for maintaining the blowout temperature at a first temperature and adjusting the blowout flow rate so that the temperature of the target space (70) becomes a set temperature. Air conditioning system.

2. An air conditioning system (10) comprising a treatment unit (20) that sucks in air and adjusts its temperature, the treatment unit (20) blowing the temperature-adjusted air into a target space (70) to form a temperature stratification in the target space (70), a controller (60) that performs a first control operation when a load index correlated with an air conditioning load of the target space (70) is lower than a reference value, and that performs a second control operation when the load index is higher than the reference value, the flow rate of air blown out from the air conditioning system (10) to the target space (70) is the blowout flow rate; the temperature of the air blown out from the air conditioning system (10) to the target space (70) is the blowout temperature; the first control action is an action of maintaining the blowout flow rate at a first flow rate and adjusting the blowout temperature so that the temperature of the target space (70) becomes a set temperature; The second control operation is an operation of maintaining the blowout flow rate at a second flow rate greater than the first flow rate, and adjusting the blowout temperature so that the temperature of the target space (70) becomes a set temperature. Air conditioning system.

3. a blow-out unit (32) that supplies the air whose temperature has been adjusted by the treatment unit (20) to a lower part of the target space (70); a suction unit (31) that sucks in air from an upper portion of the target space (70).

3. The air conditioning system according to claim 1 or 2.

4. The blow-out unit (32) is installed in the upper part of the target space (70), and supplies the air temperature-adjusted by the treatment unit (20) to the lower part of the target space (70) by blowing the air toward the floor of the target space (70). The air conditioning system according to claim 3 .

5. The load index is the difference between the temperature of the target space and the blowout temperature.

3. The air conditioning system according to claim 1 or 2.

6. The load index is the difference between the temperature of the air sucked by the suction unit (31) from the target space (70) and the blowout temperature. The air conditioning system according to claim 3 .

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