Air-conditioning system and control method

Abstract

[Problem] To provide an air-conditioning system capable of carrying out introduction of outside air in order to further enhance the energy-saving effect. [Solution] An air-conditioning system 1 comprises: an air-conditioning device 10 that introduces outside air into a space 3 to be air-conditioned; a first acquisition unit 20 that acquires a predicted temperature of the outside air; and a control unit 40 that controls the timing of introduction of the outside air into the space 3 to be air-conditioned by the air-conditioning device 10, by using the predicted temperature of the outside air acquired by the first acquisition unit 20. The control unit 40 controls the air-conditioning device 10 so that outside air having the lowest temperature is introduced into the space 3 to be air-conditioned when cooling is to be performed on the space 3 to be air-conditioned, and controls the air-conditioning device 10 so that outside air having the highest temperature is introduced into the space 3 to be air-conditioned when heating is to be performed on the space 3 to be air-conditioned.

Description

Air conditioning system and control method

[0001] The present invention relates to an air conditioning system that introduces outside air into an air-conditioned space.

[0002] In the past, in air conditioning systems that condition an air-conditioned space that has an opening to the outdoors, when the outdoor air temperature is on the target side of the temperature adjustment relative to the temperature of the air-conditioned space, the air conditioning system has been controlled so that air flows into the air-conditioned space from the opening (see, for example, Patent Document 1). Such a method can achieve energy savings.

[0003] Japanese Patent Application Laid-Open No. 2020-115053

[0004] However, conventional air conditioning systems determine whether to introduce outside air depending on the temperature difference between indoors and outdoors at the time of control. This poses a problem in that the energy-saving effect is limited. For example, in commercial facilities where the air conditioning is not operated at night, the low-temperature outside air in the early morning in summer cannot be introduced into the air-conditioned space, and opportunities to introduce outside air are limited.

[0005] The present invention has been made to solve the above-mentioned problems, and aims to provide an air conditioning system or the like that can introduce outside air to further enhance the energy-saving effect.

[0006] In order to achieve the above-mentioned object, an air conditioning system according to one aspect of the present invention comprises an air conditioning device that introduces outside air into an air-conditioned space, a first acquisition unit that acquires a predicted temperature or predicted specific enthalpy of the outside air, and a control unit that controls the timing of the air conditioning device introducing the outside air into the air-conditioned space using the predicted temperature or predicted specific enthalpy of the outside air acquired by the first acquisition unit, and the control unit controls the air conditioning device so that the outside air that has the smallest thermal load on the air-conditioned space is introduced into the air-conditioned space.

[0007] With this configuration, it becomes possible to introduce outside air at an optimum temperature or optimum specific enthalpy into the air-conditioned space, thereby further increasing the energy-saving effect.

[0008] In addition, in an air conditioning system according to one aspect of the present invention, the air conditioning device is capable of introducing outside air taken in through a plurality of outside air inlets located at different positions into the air-conditioned space, and further includes a second acquisition unit that acquires the current temperature or current specific enthalpy of the outside air at each of the plurality of outside air inlets, and when the outside air is introduced into the air-conditioned space by the air conditioning device, the control unit may use the current temperature or current specific enthalpy of the outside air acquired by the second acquisition unit to control the air conditioning device so that the outside air taken in through the outside air inlet that has the smallest heat load on the air-conditioned space is introduced into the air-conditioned space.

[0009] With this configuration, it is possible to introduce outside air into the air-conditioned space from the outside air inlet with the most suitable temperature or specific enthalpy among the multiple outside air inlets, thereby further improving the energy saving effect.

[0010] In addition, an air conditioning system according to one aspect of the present invention may further include a third acquisition unit that acquires the temperature or specific enthalpy of the air-conditioned space, and the control unit may control the air conditioning device so that outside air is introduced into the air-conditioned space within a range in which the temperature or specific enthalpy acquired by the third acquisition unit does not exceed a target value in the direction of adjustment of the temperature or specific enthalpy.

[0011] With this configuration, for example, when cooling the air-conditioned space and the temperature of the outside air is lower than the target temperature of the air-conditioned space, it is possible to prevent excessive outside air from being taken into the air-conditioned space, thereby reducing the energy required to introduce outside air.

[0012] In addition, in an air conditioning system according to one aspect of the present invention, the control unit may control the air conditioning device so that the greater the daily difference in predicted temperature or predicted specific enthalpy acquired by the first acquisition unit, the greater the amount of outside air introduced into the air-conditioned space at the time of introducing outside air.

[0013] This configuration allows for the introduction of more outside air when the effectiveness of introducing outside air is high. For example, even if night purging is performed uniformly in summer, energy savings may not be achieved. This is because the outdoor temperature may not drop significantly at night or rise significantly during the day. If more outside air is introduced when introducing outside air is not effective, extra energy will be consumed to introduce the outside air. However, by adjusting the amount of outside air introduced according to the diurnal difference in the predicted outside air temperature or predicted specific enthalpy, such extra energy consumption can be reduced.

[0014] Furthermore, a control method according to one aspect of the present invention is a control method for an air conditioning device that introduces outside air into an air-conditioned space, and includes the steps of acquiring a predicted temperature or predicted specific enthalpy of the outside air, and controlling the timing of introducing the outside air into the air-conditioned space by the air conditioning device using the acquired predicted temperature or predicted specific enthalpy of the outside air, and in the step of controlling the timing of introducing the outside air, includes the step of controlling the air conditioning device so that the outside air that has the smallest thermal load on the air-conditioned space is introduced into the air-conditioned space.

[0015] According to an air conditioning system or the like according to one aspect of the present invention, it becomes possible to introduce outside air of an optimum temperature or specific enthalpy into an air-conditioned space, thereby further enhancing the energy-saving effect.

[0016] Schematic diagram showing the configuration of an air conditioning system according to an embodiment of the present invention; Functional block diagram showing the configuration related to the control of the air conditioning system according to the embodiment; External perspective view showing an example of a building in which an air-conditioned space exists according to the embodiment; Diagram showing predicted changes in outside air temperature according to the embodiment; Flowchart showing the operation of the air conditioning system according to the embodiment; Functional block diagram showing another example of the configuration related to the control of the air conditioning system according to the embodiment.

[0017] An air conditioning system and a method for controlling an air conditioner according to the present invention will be described below using embodiments. In the following embodiments, components and steps denoted by the same reference numerals are the same or equivalent, and repeated description may be omitted. The air conditioning system according to this embodiment uses a predicted temperature of the outside air to introduce outside air at a temperature suitable for introduction into the air-conditioned space.

[0018] FIG. 1 is a schematic diagram showing the configuration of an air conditioning system 1 according to this embodiment, and FIG. 2 is a functional block diagram showing the configuration related to control of the air conditioning system 1. The air conditioning system 1 includes an air conditioner 10, a first acquisition unit 20, a second acquisition unit 30, and a control unit 40, and may further include a duct 61 for supply air (SA) to an air-conditioned space 3 and a duct 62 for return air (RA) from the air-conditioned space 3, as necessary. The air-conditioned space 3 is a space to be air-conditioned by the air-conditioning system 1. The air-conditioned space 3 is not particularly limited, and may be, for example, an office, a commercial facility, a store, a station, an airport, an underground mall, or the like.

[0019] The air conditioner 10 introduces outside air (OA) taken in through an outside air inlet into the air-conditioned space 3. In this embodiment, as shown in FIG. 1 , a case will be mainly described in which the air conditioner 10 can introduce outside air OA1 to OA3 taken in through three outside air inlets 51 to 53, respectively, into the air-conditioned space 3. The air conditioner 10 may also adjust the temperature of the air supplied to the air-conditioned space 3, for example. In this embodiment, a case will mainly be described in which the air conditioner 10 both introduces outside air into the air-conditioned space 3 and adjusts the temperature of the air in the air-conditioned space 3.

[0020] The outside air inlets 51-53 are intakes for taking outside air into the ducts 14b-14d. The multiple outside air inlets 51-53 may be located at different positions, for example. Different positions may mean different positions in at least one of the vertical and horizontal directions. As an example, as shown in FIG. 3 , the outside air inlets 51-53 may be located at different positions in the building 5 containing the air-conditioned space 3. It is preferable that the multiple outside air inlets 51-53 are located so that the outside air temperature at each position is different. Therefore, for example, when multiple outside air inlets 51-53 are located on the wall of the building 5 containing the air-conditioned space 3, at least two of the multiple outside air inlets 51-53 may be located on wall surfaces facing different directions. Specifically, the outside air inlet 51 may be located on the north-facing wall of the building 5, and the outside air inlet 53 may be located on the west-facing wall of the building 5. Although the present embodiment will be described primarily with reference to a case where three outside air inlets 51 to 53 are used, the number of outside air inlets may be, for example, one, or any number greater than or equal to two. Ideally, it is preferable to provide an outside air inlet on each wall facing each direction of the building. It is even more preferable, for example, to provide outside air inlets at different vertical positions on each wall. As an example, an outside air inlet may be provided at an upper position and a lower position on each of the north-facing, east-facing, south-facing, and west-facing walls of the building. In this case, the number of outside air inlets would be eight.

[0021] For example, the air conditioner 10 may include fans 11 and 12, a coil 13, a return air duct 14a, outside air introduction ducts 14b to 14d, an exhaust air (EA) duct 14e, and dampers 15a to 15e provided in the ducts 14a to 14e, respectively. For example, one end of the exhaust air duct 14e may be connected to the return air duct 14a at a position between the damper 15a and the fan 12.

[0022] The blower 11 sends return air or outside air to the air-conditioned space 3. In addition, when the temperature or humidity of the air is adjusted by the coil 13, the adjusted air is sent to the air-conditioned space 3 by the blower 11.

[0023] The blower 12 exhausts the return air from the air-conditioned space 3 and / or sends it to the blower 11. The ratio of exhaust air to sending it to the blower 11 may be changed by adjusting the airflow rates of the dampers 15a and 15e, for example.

[0024] The coil 13 is a heat exchanger for adjusting the temperature of the air. The coil 13 may be supplied with cold water or hot water from a heat source device 9 having, for example, a boiler or a refrigerator. When cooling is performed by the air conditioner 10, cold water may be supplied to the coil 13 from the heat source device 9, and when heating is performed by the air conditioner 10, hot water may be supplied to the coil 13 from the heat source device 9. The coil 13 may also adjust the humidity of the air, i.e., dehumidify, for example. In this case, cold water at a temperature equal to or lower than the dew point temperature of the air passing through the coil 13 may be supplied to the coil 13.

[0025] The volume of supply air supplied to the air-conditioned space 3 may be adjusted, for example, by the blower 11, or by a variable air volume (VAV) device provided in the duct 61 through which the supply air passes. When adjusting the volume of air by the blower 11, the air conditioner 10 may use a blower 11 that can adjust the volume of air, such as an inverter-controlled blower 11 or a blower 11 that uses a DC motor.

[0026] The dampers 15a to 15e may be, for example, motor dampers, and the air volume may be adjusted by the control unit 40. For example, by adjusting the air volume of the dampers 15a and 15e, it is possible to change the proportion of the return air that is exhausted. Also, for example, by adjusting the air volume of the dampers 15b to 15d, it is possible to change the outside air inlet that takes in outside air and the air volume of the outside air.

[0027] The first acquisition unit 20 acquires a predicted outdoor air temperature. This predicted temperature may be a predicted air temperature at the location or region where the air-conditioned space 3 is located. The predicted temperature acquired by the first acquisition unit 20 may be, for example, a predicted air temperature for a predetermined period from the present. The predetermined period may be, for example, 24 hours or longer. It is preferable that this predetermined period includes a time period during which the temperature is suitable for introducing air into the air-conditioned space 3. The predicted outdoor air temperature acquired by the first acquisition unit 20 preferably indicates future changes in the outdoor air temperature over time, as shown in FIG. 4 . The predicted outdoor air temperature may be a predicted outdoor air temperature for each predetermined time period, for example, every hour. The first acquisition unit 20 may acquire the predicted outdoor air temperature from, for example, the Japan Meteorological Agency or a private company that provides weather information. As an example, the first acquisition unit 20 may acquire the predicted outdoor air temperature at the location or region where the air-conditioned space 3 is located via a communication line such as the Internet. As another example, the first acquisition unit 20 may acquire the predicted outside air temperature by predicting the outside air temperature at the location where the air-conditioned space 3 is located using weather information such as past outside air temperatures at the location where the air-conditioned space 3 is located and weather information such as future weather in the area where the air-conditioned space 3 is located.

[0028] The second acquisition unit 30 acquires the current temperature of the outside air at each of the plurality of outside air inlets 51 to 53. For example, the second acquisition unit 30 may acquire the current temperature of the outside air measured by the temperature sensors 31 to 33 arranged at the plurality of outside air inlets 51 to 53, respectively, from the temperature sensors 31 to 33. Acquisition of this current temperature may be, for example, reception of the current temperature transmitted from the temperature sensors 31 to 33 via a wired or wireless communication line. Note that, as an example, the second acquisition unit 30 may include the temperature sensors 31 to 33. In this case, acquisition of the current temperature by the second acquisition unit 30 may be measurement of the current temperature.

[0029] It is preferable that the temperature sensors 31 to 33 measure the temperature of the outside air near the outside air inlets 51 to 53. For example, the temperature sensors 31 to 33 may be disposed inside the ducts 14b to 14d near the outside air inlets 51 to 53, or may be disposed outside the ducts 14b to 14d near the outside air inlets 51 to 53.

[0030] The control unit 40 uses the predicted outside air temperature acquired by the first acquisition unit 20 to control the timing of introducing outside air into the air-conditioned space 3 by the air conditioner 10. Based on the predicted outside air temperature, the control unit 40 can identify the timing at which the outside air will have the most favorable temperature to introduce into the air-conditioned space 3. Then, based on the identification result, the control unit 40 may control the air conditioner 10 so that the outside air at that favorable temperature is introduced into the air-conditioned space 3.

[0031] The control unit 40 may control the air conditioner 10 so that the outside air with the smallest thermal load on the air-conditioned space 3 is introduced into the air-conditioned space 3. The outside air with the smallest thermal load on the air-conditioned space 3 may be considered to be the outside air that, when introduced into the air-conditioned space 3, can minimize the thermal load on the air-conditioned space 3. More specifically, for example, when cooling the air-conditioned space 3, the control unit 40 may control the air conditioner 10 so that the lowest temperature outside air is introduced into the air-conditioned space 3, and when heating the air conditioner 10, the control unit 40 may control the air conditioner 10 so that the highest temperature outside air is introduced into the air-conditioned space 3. The case when cooling the air-conditioned space 3 may refer to a season when cooling is performed on the air-conditioned space 3. Therefore, when the control unit 40 controls the air conditioner 10 to introduce outside air, the air temperature does not necessarily need to be adjusted by the air conditioner 10. The same applies to a case when heating the air-conditioned space 3.

[0032] Controlling the air conditioner 10 so that the coldest outside air is introduced into the air-conditioned space 3 may mean controlling the air conditioner 10 so that the outside air during the time period with the lowest predicted temperature is introduced into the air-conditioned space 3. Note that because this introduction of outside air is performed based on the predicted temperature, it is possible that the lowest temperature outside air is not actually introduced into the air-conditioned space 3, but it is considered possible to introduce outside air that is at least close to the lowest temperature into the air-conditioned space 3. The same applies when controlling the air conditioner 10 so that the warmest outside air is introduced into the air-conditioned space 3.

[0033] More specifically, if the acquired predicted outside air temperature is the one shown in Figure 4 and the air-conditioned space 3 is being cooled, the control unit 40 identifies the time point T1 at which the temperature is lowest among the predicted temperatures. Then, at the identified time point T1, the control unit 40 may control the air conditioner 10 to introduce outside air into the air-conditioned space 3. Furthermore, if the acquired predicted outside air temperature is the one shown in Figure 4 and the air-conditioned space 3 is being heated, the control unit 40 may identify the time point T2 at which the temperature is highest among the predicted temperatures. Then, at the identified time point T2, the control unit 40 may control the air conditioner 10 to introduce outside air into the air-conditioned space 3.

[0034] Furthermore, the control unit 40 may use the current temperature of the outside air acquired by the second acquisition unit 30 to control the air conditioner 10 so that, when the air conditioner 10 introduces outside air into the air-conditioned space 3, the outside air is introduced into the air-conditioned space 3 through an outside air inlet that has the smallest heat load on the air-conditioned space 3. More specifically, for example, when introducing outside air into the air-conditioned space 3, the control unit 40 may identify, among the multiple outside air inlets 51 to 53, an outside air inlet that has the most suitable outside air temperature, and control the air conditioner 10 so that the outside air is introduced into the air-conditioned space 3 through the identified outside air inlet. For example, when cooling the air-conditioned space 3, the control unit 40 may control the air conditioner 10 so that, when the air conditioner 10 introduces outside air into the air-conditioned space 3, the outside air is introduced into the air-conditioned space 3 through an outside air inlet that has the lowest current temperature of the outside air acquired by the second acquisition unit 30. Furthermore, for example, when heating is performed on the air-conditioned space 3, the control unit 40 may control the air-conditioning unit 10 so that when outside air is introduced into the air-conditioned space 3 by the air-conditioning unit 10, the outside air taken in from the outside air inlet whose current temperature of the outside air acquired by the second acquisition unit 30 is the highest is introduced into the air-conditioned space 3.

[0035] More specifically, when cooling is performed on the air-conditioned space 3, and the current outside air temperatures at the outside air inlets 51 to 53 acquired when the outside air is introduced into the air-conditioned space 3 are 21° C., 22° C., and 23° C., respectively, the outside air inlet 51 with the lowest outside air temperature may be selected as the outside air inlet for actually taking in the outside air, and the air conditioner 10 may be controlled so that the outside air is introduced from the selected outside air inlet 51. In this case, for example, the damper 51b may be opened and the dampers 51c and 51d may be closed, so that the outside air is introduced only from the outside air inlet 51.

[0036] Because the multiple outside air inlets 51 to 53 are provided at different positions, there is a possibility that the outside air temperature will differ from one another at the outside air inlets 51 to 53. Therefore, by introducing outside air into the air-conditioned space 3 from the outside air inlet with the most suitable outside air temperature, it becomes possible to introduce outside air that is more suitable for air conditioning into the air-conditioned space 3, thereby further promoting energy conservation.

[0037] Here, when outside air is being introduced into the air-conditioned space 3 as described above, for example, the damper 15a of the return air duct 14a may be closed and the damper 15e of the exhaust air duct 14e may be open. In this way, the air in the air-conditioned space 3 can be efficiently replaced with outside air. Furthermore, when outside air is being introduced into the air-conditioned space 3, for example, the air volumes of the fans 11 and 12 may be approximately the same.

[0038] Furthermore, when outside air is introduced into the air-conditioned space 3 as described above, it is usually preferable that a larger proportion of the outside air be introduced into the air-conditioned space 3. For example, it is preferable that 30% or more of the volume of the air-conditioned space 3 be replaced with outside air, more preferably that 50% or more be replaced with outside air, even more preferably that 70% or more be replaced with outside air, and even more preferably that 90% or more be replaced with outside air.

[0039] On the other hand, when the daily range of the predicted temperature, i.e., the difference between the maximum and minimum temperatures in a day, is small, there is little benefit in introducing outside air into the air-conditioned space 3 all at once during a specific period. Therefore, the control unit 40 may control the air conditioner 10 so that the amount of outside air introduced into the air-conditioned space 3 during the outside air introduction period increases as the daily range of the predicted temperature acquired by the first acquisition unit 20 increases. In this case, the smaller the daily range of the predicted temperature acquired by the first acquisition unit 20, the less outside air will be introduced into the air-conditioned space 3 during the outside air introduction period.

[0040] The daily range of the predicted temperature may be, for example, the value obtained by subtracting the minimum temperature H1 from the maximum temperature H2 when the predicted temperature is as shown in FIG. 4 . The daily range is typically a positive real number. For example, the control unit 40 may calculate the daily range using the predicted temperature acquired by the first acquisition unit 20, and then use information correlating the daily range with the amount of outside air introduced into the air-conditioned space 3 to determine the amount of outside air introduced corresponding to the calculated daily range, and control the air conditioner 10 to introduce outside air corresponding to the determined amount into the air-conditioned space 3. The information correlating the daily range with the amount of outside air introduced into the air-conditioned space 3 may be, for example, a table correlating the two or a function for calculating the amount of outside air introduced from the daily range.

[0041] Next, the operation of the air conditioning system 1 will be described using the flowchart of FIG. 5. (Step S101) The control unit 40 determines whether to perform processing to determine the timing of introducing outside air. If the processing to determine the timing of introducing outside air is to be performed, the process proceeds to step S102; if not, the process proceeds to step S104. The control unit 40 may, for example, periodically determine to perform processing to determine the timing of introducing outside air. As an example, the control unit 40 may determine to perform processing to determine the timing of introducing outside air at a predetermined time (e.g., midnight or 2:00 AM) every day.

[0042] (Step S102) The first acquisition unit 20 acquires a predicted outside air temperature.

[0043] (Step S103) The control unit 40 determines the time to introduce outside air using the predicted outside air temperature acquired in step S102. For example, in the cooling season, the time period when the predicted outside air temperature is lowest may be determined as the time to introduce outside air, and in the heating season, the time period when the predicted outside air temperature is highest may be determined as the time to introduce outside air. Then, the process returns to step S101. Note that the result of the determination of the time to introduce outside air may be expressed as a period from the time of determination, such as "three hours later," or may be expressed as a time, such as "5:00 AM." In the former case, for example, a timer may start timing from the time of determination.

[0044] (Step S104) The control unit 40 determines whether the time to introduce outside air determined in step S103 has arrived. If the time to introduce outside air has arrived, the process proceeds to step S105; if not, the process returns to step S101. For example, if the determined result of the time to introduce outside air is a period from the determined time, such as "three hours later," and a timer has been measuring time since the determined time, the control unit 40 may determine that the time to introduce outside air has arrived when the timer value reaches the determined result. Alternatively, for example, if the determined result of the time to introduce outside air is a time, such as "5:00 AM," the control unit 40 may determine that the time to introduce outside air has arrived when the time on a clock unit (not shown) reaches the determined result.

[0045] (Step S105) The second acquisition unit 30 acquires the current temperature of the outside air at each of the plurality of outside air inlets 51 to 53.

[0046] (Step S106) The control unit 40 determines the outdoor air inlet corresponding to the most suitable temperature among the current temperatures acquired in step S105 as the outdoor air inlet to be used to introduce outdoor air. For example, in the cooling season, the outdoor air inlet corresponding to the lowest outdoor air temperature may be determined to be the outdoor air inlet to be used to introduce outdoor air, and in the heating season, the outdoor air inlet corresponding to the highest outdoor air temperature may be determined to be the outdoor air inlet to be used to introduce outdoor air.

[0047] (Step S107) The control unit 40 controls the air conditioner 10 so that outside air is introduced into the air-conditioned space 3 from the outside air inlet determined in step S106. Through this control, for example, a predetermined volume of outside air may be introduced into the air-conditioned space 3. Then, the process returns to step S101.

[0048] Although not included in the flowchart of FIG. 5 , the temperature of the air supplied to the air-conditioned space 3 may be adjusted by the air conditioner 10 as appropriate. This temperature adjustment may be performed so that the temperature of the air in the air-conditioned space 3 becomes a desired temperature. The air temperature adjustment may be performed, for example, simultaneously with the introduction of outside air, or may be performed separately from the introduction of outside air. Furthermore, the order of the processing in the flowchart of FIG. 5 is an example, and the order of the steps may be changed as long as the same results are obtained. Furthermore, in the flowchart of FIG. 5 , the processing may be terminated by a power-off or an interrupt to terminate the processing.

[0049] Next, the operation of the air conditioning system 1 according to this embodiment will be described using a specific example. Note that this specific example will mainly describe control in the season when cooling is performed in the air-conditioned space 3.

[0050] First, at midnight, the control unit 40 determines that processing for determining the timing of introducing outside air should be performed, and transmits an instruction to the first acquisition unit 20 to acquire a predicted outside air temperature (step S101). Upon receiving this instruction, the first acquisition unit 20 accesses a server that provides meteorological information via the Internet, acquires from the server a predicted temperature, which is a one-day temperature forecast corresponding to the area where the air-conditioned space 3 is located, and transmits the predicted temperature to the control unit 40 (step S102). The predicted temperature is assumed to be, for example, the one shown in FIG. 4.

[0051] Upon receiving the predicted temperature, the control unit 40 determines the time T1 when the temperature is lowest as the time to introduce outside air (step S103). For example, this time T1 may be 5:00 a.m. The control unit 40 may store the time to introduce outside air, "5:00 a.m." in a memory unit or the like.

[0052] Thereafter, at 5:00 AM, when it is time to introduce outside air, the control unit 40 determines that outside air should be introduced into the air-conditioned space 3 and instructs the second acquisition unit 30 to acquire the current temperature at each of the outside air inlets 51-53 (step S104). Upon receiving this instruction, the second acquisition unit 30 acquires the current temperatures of the outside air at each of the outside air inlets 51-53 from the temperature sensors 31-33 disposed at the outside air inlets 51-53, respectively, and passes the acquired temperatures to the control unit 40 (step S105). It is assumed that the current temperatures acquired by the temperature sensors 31-33 are 21°C, 22°C, and 23°C, respectively.

[0053] Upon receiving the current temperatures, the control unit 40 determines the outdoor air inlet 51 corresponding to 21°C, the lowest of the received temperatures, as the outdoor air inlet to be used to introduce outdoor air (step S106), and controls the air conditioner 10 to introduce outdoor air into the air-conditioned space 3 through the outdoor air inlet 51 (step S107). Note that, at this point, the temperature of the air supplied to the air-conditioned space 3 has not been adjusted. In this case, the control unit 40 controls the dampers 15a, 15c, and 15d to be closed and the dampers 15b and 15e to be opened. The control unit 40 also operates the blowers 11 and 12 to introduce outdoor air OA1 from the outdoor air inlet 51 into the air-conditioned space 3 and to exhaust all return air from the air-conditioned space 3. This introduction of outdoor air may be continued, for example, until a predetermined volume of outdoor air has been introduced into the air-conditioned space 3.

[0054] As described above, the air conditioning system 1 according to this embodiment can introduce outside air at an optimal temperature into the air-conditioned space 3. As a result, air conditioning can be performed more efficiently. For example, the introduction of outside air can further reduce the energy consumption of the heat source equipment 9 when air-conditioning the air-conditioned space 3, thereby further enhancing energy-saving effects. Furthermore, when performing air conditioning such as cooling in the air-conditioned space 3, a certain amount of outside air must be introduced into the air-conditioned space 3 for ventilation, even if the outside air temperature is not suitable for air conditioning. As a result, there is a problem that the efficiency of the air conditioning decreases. On the other hand, for example, in the season when air conditioning is performed, by introducing a large amount of outside air with the lowest temperature into the air-conditioned space 3 in advance in the early morning, the amount of outside air introduced can be reduced when cooling is performed during the daytime. In other words, by introducing outside air at an optimal temperature, the amount of ventilation during normal air conditioning can be reduced, thereby improving the efficiency of air conditioning.

[0055] Furthermore, by introducing outside air from the outside air inlet with the most suitable current temperature among the plurality of outside air inlets, energy conservation can be further promoted. Also, for example, if a large amount of outside air is introduced when the daily temperature difference is small, the fans 11 and 12 will be operated unnecessarily, which will result in a countermeasure to energy conservation. However, by increasing the amount of outside air introduced as the daily temperature difference of the predicted temperature becomes larger, such a situation can be prevented.

[0056] In the present embodiment, the case where the outdoor air inlet through which the outdoor air is introduced is determined using the current temperature of the outdoor air at each of the plurality of outdoor air inlets 51 to 53 has been mainly described, but this is not necessarily the case. The outdoor air inlet through which the outdoor air is introduced may also be determined using the current specific enthalpy of the outdoor air at each of the plurality of outdoor air inlets 51 to 53. In this case, the second acquisition unit 30 may acquire the current specific enthalpy of the outdoor air at each of the plurality of outdoor air inlets 51 to 53 instead of the current temperature of the outdoor air at each of the plurality of outdoor air inlets 51 to 53. The specific enthalpy can be calculated using, for example, two values ​​from among the dry-bulb temperature, the wet-bulb temperature, the relative humidity, and the absolute humidity. Therefore, the second acquisition unit 30 may acquire current values ​​measured by two types of sensors (e.g., a temperature sensor for measuring dry-bulb temperature and a humidity sensor for measuring relative humidity) arranged at each of the outdoor air inlets 51-53, and calculate the current specific enthalpy using the two acquired current values. Measurement of the current values ​​by the two types of sensors is preferably performed near the outdoor air inlets 51-53, similar to measurement of the current temperature by the temperature sensors 31-33. Furthermore, the second acquisition unit 30 may acquire the current specific enthalpy calculated using the current values ​​measured by the two types of sensors arranged at each of the outdoor air inlets 51-53 from a specific enthalpy acquisition device that performed the calculation. The second acquisition unit 30 may acquire the two current values ​​from the two types of sensors or the current specific enthalpy from the specific enthalpy acquisition device by receiving transmitted information via a wired or wireless communication line, for example. As an example, the second acquisition unit 30 may have two types of sensors arranged at each of the plurality of outside air inlets 51 to 53. In this case, the second acquisition unit 30 may acquire the current specific enthalpy by measuring the current value using the two types of sensors and calculating the specific enthalpy using the measurement results.Furthermore, even when the outside air inlet for introducing the outside air is determined using the current specific enthalpy of the outside air, it is preferable that the multiple outside air inlets 51 to 53 are arranged so that the specific enthalpy of the outside air at each position is different.

[0057] When the second acquisition unit 30 acquires the current specific enthalpy of the outside air at each of the multiple outside air inlets 51 to 53, the control unit 40 may use the current specific enthalpy of the outside air acquired by the second acquisition unit 30 to control the air conditioning unit 10 so that when the outside air is introduced into the air-conditioned space 3 by the air conditioning unit 10, the outside air taken in from the outside air inlet that has the smallest heat load of the outside air on the air-conditioned space 3 is introduced into the air-conditioned space 3. More specifically, when the air conditioning device 10 introduces outside air into the air-conditioned space 3, the control unit 40 may, for example, control the air conditioning device 10 so that, if cooling is performed on the air-conditioned space 3, the outside air taken in through the outside air inlet having the lowest current specific enthalpy of the outside air acquired by the second acquisition unit 30 is introduced into the air-conditioned space 3, and, if heating is performed on the air-conditioned space 3, control the air conditioning device 10 so that the outside air taken in through the outside air inlet having the highest current specific enthalpy of the outside air acquired by the second acquisition unit 30 is introduced into the air-conditioned space 3. In this way, if cooling is performed, the outside air with the lowest specific enthalpy, for example, outside air with a low temperature and humidity, can be introduced into the air-conditioned space 3, and if heating is performed, the outside air with the highest specific enthalpy, for example, outside air with a high temperature and humidity, can be introduced into the air-conditioned space 3.

[0058] Furthermore, in the present embodiment, the air conditioner 10 is capable of introducing outside air taken in through multiple outside air inlets 51-53 into the air-conditioned space 3, and the case where the air conditioner takes in the outside air through one of the multiple outside air inlets 51-53 that has the optimal current temperature and current specific enthalpy of the outside air has been mainly described. However, this is not necessarily the case. For example, even if the air conditioner 10 is capable of introducing outside air taken in through multiple outside air inlets 51-53 into the air-conditioned space 3, the air conditioner 10 may take in outside air through all of the outside air inlets 51-53. Furthermore, for example, the air conditioner 10 may take in outside air through only one outside air inlet. In these cases, the air conditioning system 1 may not be provided with, for example, the second acquisition unit 30.

[0059] Although the present embodiment has been described primarily with reference to a case where the timing of introducing outside air is controlled using a predicted outside air temperature, this is not necessarily the case. The timing of introducing outside air may also be controlled using a predicted outside air enthalpy. In this case, the first acquisition unit 20 may acquire a predicted specific enthalpy instead of a predicted temperature. As described above, the specific enthalpy can be calculated using two values, for example, from the dry-bulb temperature, the wet-bulb temperature, the relative humidity, and the absolute humidity. Therefore, the first acquisition unit 20 may acquire two values, for example, from the predicted dry-bulb temperature, the predicted wet-bulb temperature, the predicted relative humidity, and the predicted absolute humidity, and calculate the predicted specific enthalpy using the two acquired values. Alternatively, the first acquisition unit 20 may acquire the predicted specific enthalpy of the outside air from, for example, the Japan Meteorological Agency or a private company that provides weather information. Note that the first acquisition unit 20 may acquire the predicted specific enthalpy in the same manner as described above, except that the acquisition target is changed from the predicted temperature to the predicted specific enthalpy.

[0060] Even when the predicted specific enthalpy is acquired by the first acquisition unit 20, the control unit 40 may control the air conditioner 10 so that the outside air with the smallest heat load on the air-conditioned space 3 is introduced into the air-conditioned space 3. More specifically, for example, when cooling the air-conditioned space 3, the control unit 40 may control the air conditioner 10 so that the outside air with the lowest specific enthalpy is introduced into the air-conditioned space 3, and when heating the air conditioner 10, the control unit 40 may control the air conditioner 10 so that the outside air with the highest specific enthalpy is introduced into the air-conditioned space 3.

[0061] Furthermore, in cases where a predicted specific enthalpy is acquired, the control unit 40 may control the air conditioner 10 so that, for example, the greater the daily range difference in the predicted specific enthalpy acquired by the first acquisition unit 20, the greater the amount of outside air introduced into the air-conditioned space 3 at the time of introducing the outside air. This control is similar to the control that increases the amount of outside air introduced into the air-conditioned space 3 at the time of introducing the outside air, the greater the daily range difference in the predicted temperature, except that the predicted temperature becomes the predicted specific enthalpy, and detailed description thereof will be omitted.

[0062] Furthermore, in this embodiment, the introduction of outside air into the air-conditioned space 3 may be controlled according to the temperature of the air-conditioned space 3 after the introduction of the outside air. In this case, the air-conditioning system 1 may further include a third acquisition unit 50 that acquires the temperature of the air-conditioned space 3, as shown in FIG. 6 . The third acquisition unit 50 may acquire, for example, the temperature of the air-conditioned space 3 measured by a temperature sensor 51 disposed in the air-conditioned space 3 from the temperature sensor 51. This acquisition of the current temperature may be, for example, reception of the current temperature transmitted from the temperature sensor 51 via a wired or wireless communication line. As an example, the third acquisition unit 50 may include the temperature sensor 51. In this case, the acquisition of the temperature of the air-conditioned space 3 by the third acquisition unit 50 may be measurement of the temperature of the air-conditioned space 3. Furthermore, the temperature of the air-conditioned space 3 acquired by the third acquisition unit 50 may be, for example, a representative value of temperatures of the air-conditioned space 3 measured at multiple positions. The representative value may be, for example, an average value, a median value, a maximum value, a minimum value, or the like.

[0063] When the temperature of the air-conditioned space 3 is acquired by the third acquisition unit 50, the control unit 40 may control the air conditioner 10 to introduce outside air into the air-conditioned space 3 within a range in which the acquired temperature does not exceed a target value in the temperature adjustment direction. The temperature adjustment direction may be the temperature adjustment direction in air conditioning. For example, if cooling is performed on the air-conditioned space 3, it may be a temperature decreasing direction, and if heating is performed on the air-conditioned space 3, it may be a temperature increasing direction. Furthermore, the target value may be the same as or different from the target temperature of the air conditioner 10. For example, if cooling is performed, the outside air temperature is 20°C, and the target value in the temperature adjustment direction of the air-conditioned space 3 is set to 23°C, the control unit 40 may control the introduction of outside air by the air conditioner 10 so that the temperature of the air-conditioned space 3 becomes 23°C or higher. More specifically, when the temperature acquired by the third acquisition unit 50 reaches 23°C, the control unit 40 may stop introducing outside air into the air-conditioned space 3. In this way, it is possible to avoid introducing an excessive amount of outside air into the air-conditioned space 3, and it is possible to reduce the energy required to introduce the outside air.

[0064] In this case, control may also be performed using specific enthalpy instead of temperature. When control using specific enthalpy is performed, the third acquisition unit 50 may acquire the specific enthalpy of the air-conditioned space 3. This acquisition of specific enthalpy may be performed, for example, in the same manner as the acquisition of specific enthalpy by the second acquisition unit 20. Furthermore, when specific enthalpy is acquired, the control unit 40 may control the air conditioner 10 so that outside air is introduced into the air-conditioned space 3 within a range in which the acquired specific enthalpy does not exceed a target value in the direction of specific enthalpy adjustment. This control is similar to the control of outside air introduction using the temperature of the air-conditioned space 3, except that the temperature is the specific enthalpy, and detailed description thereof will be omitted.

[0065] Furthermore, in this embodiment, the case where the air conditioner 10 also adjusts the temperature of the air supplied to the air-conditioned space 3 has been mainly described, but this is not necessarily the case. The air conditioner 10 is for introducing outside air into the air-conditioned space 3, and the temperature of the air supplied to the air-conditioned space 3 may be adjusted by another air conditioner separately. In this case, the air conditioner 10 does not need to be equipped with the coil 13.

[0066] Furthermore, in the above embodiments, each process or function may be realized by centralized processing by a single device or a single system, or may be realized by distributed processing by multiple devices or multiple systems.

[0067] Furthermore, in the above embodiment, when two or more components included in the air conditioning system 1 have a communication device, an input device, etc., the two or more components may physically have a single device, or may have separate devices.

[0068] In the above embodiments, each component may be configured with dedicated hardware, or a software-implementable component may be implemented by executing a program. For example, a software-implementable component may be implemented by a program execution unit such as a CPU reading and executing a software program recorded on a recording medium such as a hard disk or semiconductor memory. During execution, the program execution unit may execute the program while accessing a storage unit or recording medium. The program may also be executed by being downloaded from a server or the like, or by being read from a predetermined recording medium (e.g., an optical disk, a magnetic disk, a semiconductor memory, etc.). The program may also be used as a program constituting a program product. The program may be executed by a single computer or multiple computers. That is, centralized processing or distributed processing may be performed.

[0069] Furthermore, the above-described embodiments are merely examples for specifically implementing the present invention, and are not intended to limit the technical scope of the present invention. The technical scope of the present invention is defined by the claims, not by the description of the embodiments, and is intended to include modifications within the literal scope of the claims and within the scope of equivalent meanings.

Claims

1. An air conditioning system comprising: an air conditioning device that introduces outside air into an air-conditioned space; a first acquisition unit that acquires a predicted temperature or predicted specific enthalpy of the outside air; and a control unit that controls the timing of the air conditioning device introducing the outside air into the air-conditioned space using the predicted temperature or predicted specific enthalpy of the outside air acquired by the first acquisition unit, wherein the control unit controls the air conditioning device so that the outside air that has the smallest heat load on the air-conditioned space is introduced into the air-conditioned space, and controls the air conditioning device so that the amount of outside air introduced into the air-conditioned space at the time of introducing the outside air increases the greater the daily difference in the predicted temperature or predicted specific enthalpy acquired by the first acquisition unit.

2. The air conditioning system of claim 1, wherein the air conditioning device is capable of introducing outside air taken in through a plurality of outside air inlets located at different positions into the air-conditioned space, and further comprises a second acquisition unit that acquires the current temperature or current specific enthalpy of the outside air at each of the plurality of outside air inlets, and the control unit, when the air conditioning device introduces outside air into the air-conditioned space, uses the current temperature or current specific enthalpy of the outside air acquired by the second acquisition unit to control the air conditioning device so that the outside air taken in through the outside air inlet that has the smallest heat load on the air-conditioned space is introduced into the air-conditioned space.

3. An air conditioning system as described in claim 1, further comprising a third acquisition unit that acquires the temperature or specific enthalpy of the air-conditioned space, wherein the control unit controls the air conditioning device so that outside air is introduced into the air-conditioned space within a range in which the temperature or specific enthalpy acquired by the third acquisition unit does not exceed a target value in the direction of adjustment of the temperature or specific enthalpy.

4. A control method for an air conditioning device that introduces outside air into an air-conditioned space, comprising: a step of acquiring a predicted temperature or predicted specific enthalpy of the outside air; and a step of controlling the timing of introducing the outside air into the air-conditioned space by the air conditioning device using the acquired predicted temperature or predicted specific enthalpy of the outside air, wherein in the step of controlling the timing of introducing the outside air, the air conditioning device is controlled so that the outside air that has the smallest heat load on the air-conditioned space is introduced into the air-conditioned space, and the air conditioning device is controlled so that the amount of outside air introduced into the air-conditioned space at the time of introducing the outside air increases the greater the daily difference in the acquired predicted temperature or predicted specific enthalpy.

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