Air conditioning system

Abstract

To eliminate a heat source for reheating or promote energy saving by reducing the size in an air conditioning system.SOLUTION: An air conditioning system includes: a cooling and dehumidifying section 12 for cooling and dehumidifying outside air OA introduced from an outside air introduction section 20; and a reheating section 13 for reheating dehumidification air cooled and dehumidified by the cooling and dehumidifying section 12. The air conditioning system also includes a reheating outside air introduction section 60 for guiding air of which temperature has been raised by using waste heat of an attic space S2 in the attic space S2 to the reheating section 13 as reheating outside air. In the reheating section 13, the reheating outside air introduced from the reheating outside air introduction section 60 is mixed with the dehumidification air cooled and dehumidified by the cooling and dehumidifying section 12 to reheat the dehumidification air.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to an air conditioning system including a cooling and dehumidifying unit that cools and dehumidifies outside air introduced from an outside air introduction unit, and a reheating unit that reheats the dehumidified air cooled and dehumidified by the cooling and dehumidifying unit.

Background Art

[0002] As the background art of the present invention, for example, in a dehumidifying and reheating air conditioning system, there are provided a cooling and dehumidifying unit (cooling and heating water coil for outside air treatment) that cools and dehumidifies outside air from an outside air introduction unit (outside air intake), and a reheating unit that reheats the dehumidified outside air cooled and dehumidified by the cooling and dehumidifying unit. A part of the outside air introduced from the outside air introduction unit (raw outside air) is bypassed around the cooling and dehumidifying unit as reheating outside air and introduced into the reheating unit, and the dehumidified outside air is reheated by mixing it with the reheating unit (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the technique described in Patent Document 1, the outside air from the outside air introduction unit (outside air intake) is divided into cooling and dehumidifying outside air that is cooled and dehumidified by the cooling and dehumidifying unit (cooling and heating water coil for outside air treatment) and reheating outside air (raw outside air) that bypasses the cooling and dehumidifying unit and is introduced into the reheating unit. Thus, while ensuring the amount of outside air required for ventilation, the amount of outside air volume cooled and dehumidified by the cooling and dehumidifying unit can be reduced. As a result, the amount of energy required for cooling and dehumidifying the outside air can be reduced, and the amount of energy required for reheating the dehumidified outside air cooled and dehumidified by the cooling and dehumidifying unit can be reduced.

[0005] However, in the technology described in Patent Document 1, since fresh air is mixed with the dehumidified outside air that has been cooled and dehumidified as the reheating outside air, when the outside air temperature is low, reheating by mixing the dehumidified outside air and the fresh air becomes insufficient, and the temperature of the conditioned air supplied from the blower into the room fails to reach the required temperature, resulting in inconvenience. In order to avoid such inconvenience, it is necessary to provide a heat source that can ensure sufficient heat quantity required for reheating the dehumidified outside air, and there is room for improvement in promoting energy saving by eliminating or miniaturizing the heat source for reheating.

[0006] In view of this situation, the main problem of the present invention is to promote energy saving by eliminating or miniaturizing the heat source for reheating in an air conditioning system.

Means for Solving the Problem

[0007] The first characteristic configuration of the present invention is an air conditioning system including a cooling and dehumidifying unit that cools and dehumidifies the outside air introduced from an outside air introduction unit, and a reheating unit that reheats the dehumidified air cooled and dehumidified by the cooling and dehumidifying unit, equipped with a reheating outside air introduction unit that guides the air heated by the waste heat of the attic space in the attic space to the reheating unit as the reheating outside air, In the reheating unit, the reheating outside air introduced from the reheating outside air introduction unit is mixed with the dehumidified air cooled and dehumidified by the cooling and dehumidifying unit to reheat the dehumidified air.

[0008] According to this configuration, when cooling and dehumidifying is required, the outside air introduced into the outside air introduction unit is cooled and dehumidified by the cooling and dehumidifying unit and then supplied to the reheating unit as dehumidified air. At the same time, in the attic space, the air heated by the waste heat of the attic space stored in the attic space due to the roof surface being heated by sunlight is guided to the reheating unit as the reheating outside air, and in the reheating unit, it is mixed with the dehumidified air cooled and dehumidified by the cooling and dehumidifying unit to reheat the dehumidified air.

[0009] In this way, by dividing the outside air into the outside air to be cooled and dehumidified and the outside air not to be cooled and dehumidified for reheating this outside air, it is possible to reduce the amount of outside air to be cooled and dehumidified in the cooling and dehumidifying section while ensuring the amount of outside air necessary for ventilation. As a result, it is possible to use an energy-saving device with low cooling capacity as the cooling and dehumidifying section, and to reduce the amount of energy required for reheating.

[0010] Moreover, since the outside air for reheating is the air heated by the waste heat in the attic space, when this air is mixed with the dehumidified air in the reheating section to reheat the dehumidified air, the waste heat in the attic space possessed by the air is effectively utilized. As a result, even when the outside air temperature is low, the reheating of the dehumidified air by the outside air can be performed well, and the reheated dehumidified air can be supplied as air-conditioning air that satisfies the required temperature to the air-conditioned space.

[0011] As a result, while appropriately supplying air-conditioning air that satisfies the required temperature for the air-conditioned space, it is possible to promote energy saving by eliminating or reducing the size of the heat source for reheating, that is, by making the heat source for reheating unnecessary or smaller.

[0012] A second characteristic configuration of the present invention includes a return air introduction section that guides return air from the air-conditioned space to the reheating section. In the reheating section, the dehumidified air cooled and dehumidified in the cooling and dehumidifying section is mixed with the return air introduced from the return air introduction section to reheat the dehumidified air.

[0013] According to this configuration, in addition to the outside air for reheating described above, the return air from the air-conditioned space can also be mixed with the dehumidified air in the reheating section. As a result, for reheating the dehumidified air in the reheating section, in addition to the heat possessed by the outside air for reheating (the waste heat in the attic space), the heat possessed by the return air from the air-conditioned space can also be effectively utilized, and the reheating of the dehumidified air in the reheating section can be performed better. As a result, it is possible to more surely promote energy saving by eliminating or reducing the size of the heat source for reheating.

[0014] The third characteristic configuration of the present invention includes a reheating outside air volume adjustment unit that adjusts the air volume of the reheating outside air introduced into the reheating unit in the outside air introduction unit for reheating, a return air volume adjustment unit that adjusts the air volume of the return air introduced into the reheating unit in the return air introduction unit, and a control unit that controls the reheating outside air volume adjustment unit and the return air volume adjustment unit so that the reheating outside air is preferentially supplied to the reheating unit over the return air.

[0015] According to this configuration, the reheating outside air whose holding heat temperature becomes high by being heated by the waste heat in the attic space is preferentially supplied to the reheating unit, so that the reheating of the dehumidified air in the reheating unit can be efficiently performed. And, for example, when the amount of heat held by the reheating outside air decreases, it can be supplemented by the holding heat of the return air from the air-conditioned space, and the reheating of the dehumidified air in the reheating unit can be stably performed. As a result, it is possible to more suitably promote energy saving by reducing or miniaturizing the heat source for reheating.

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0017] Hereinafter, embodiments of the air conditioning system according to the present invention will be described with reference to the drawings. In the schematic diagrams of FIGS. 2 to 5 showing the respective control states of the air conditioning system exemplified in the present embodiment, the paths through which air and chilled water flow in each control state are indicated by thick solid lines.

[0018] As shown in FIG. 1, the air conditioning system exemplified in the present embodiment is configured as a system that supplies conditioned air SA obtained by processing outside air OA to an air-conditioned space S1 such as an office or a conference room provided in a building such as an office building or a conference hall. This air conditioning system is provided with an air conditioner 10 that adjusts the temperature and humidity of the outside air OA, and an outside air introduction duct 20 as an outside air introduction unit that introduces the outside air OA into the air conditioner 10. Although illustration is omitted, in this air conditioning system, a plurality of air conditioners 10 are provided in the air conditioning system in a parallel state in which the outside air OA from the outside air introduction duct 20 is distributively supplied. Further, as shown in FIG. 1, this air conditioning system is provided with a plurality of supply air ducts 30 that supply the conditioned air SA from each air conditioner 10 to the corresponding air-conditioned space S1, an exhaust fan 4 that discharges the air in each air-conditioned space S1 from the air-conditioned space S1, and a plurality of exhaust ducts 40. Furthermore, this air conditioning system is provided with a ventilation device 50 that ventilates the attic space S2 provided in the building together with the air-conditioned space S1 described above.

[0019] Each air conditioner 10 is equipped with an air filter 11 that collects dust and the like contained in the outside air OA introduced from the outside air introduction duct 20 from the upstream side in the air flow direction, a cooling and dehumidifying section 12 that cools and dehumidifies the outside air OA that has passed through the air filter 11, a reheating section 13 that reheats the dehumidified air cooled and dehumidified by the cooling and dehumidifying section 12, and a supply air fan 14 that supplies the reheated dehumidified air as conditioned air SA to the conditioned space S1. The cooling and dehumidifying section 12 is composed of a chilled water coil that cools and dehumidifies the outside air OA by heat exchange with chilled water CW supplied from a heat source (not shown). Also, a flow rate adjustment valve 15 for adjusting the flow rate of the chilled water CW supplied to the cooling and dehumidifying section 12 is provided.

[0020] The outside air introduction duct 20 is provided with a plurality of outside air volume adjustment sections 21 for adjusting the air volume of the outside air OA introduced from the outside air introduction duct 20 into each air conditioner 10. A variable air volume control device (VAV) is adopted for the outside air volume adjustment section 21.

[0021] Each supply duct 30 is provided with a supply air temperature detector 31 for detecting the temperature and dew point temperature of the conditioned air SA supplied from the air conditioner 10 to the conditioned space S1.

[0022] Each exhaust duct 40 is provided with an exhaust air volume adjustment section 41 for adjusting the air volume of the exhaust air EA discharged from the conditioned space S1. On the upstream side of the exhaust air volume adjustment section 41 in the air flow direction in each exhaust duct 40, there are a first return air duct 42 that guides the exhaust from the conditioned space S1 as return air RA to the upstream side of the air filter 11 in the air flow direction within the air conditioner 10, and a second return air duct 43 as a return air introduction section that guides the exhaust from the conditioned space S1 as return air RA to the reheating section 13 of the air conditioner 10. The first return air duct 42 is provided with a motor damper 44 that opens and closes the first return air duct 42 to interrupt the supply of return air to the air conditioner 10 through the first return air duct 42. The second return air duct 43 is provided with a return air volume adjustment section 45 for adjusting the air volume of the return air introduced into the reheating section 13 of the air conditioner 10 by the second return air duct 43. A variable air volume control device (VAV) is adopted for the exhaust air volume adjustment section 41 and the return air volume adjustment section 45.

[0023] The ventilation device 50 is provided with an outside air introduction duct 51 for introducing outside air OA into the attic space S2, and an exhaust duct 52 for guiding the air in the attic space S2 to the outside of the house and discharging it. The air in the attic space S2 is the air that has been heated by the waste heat of the attic space S2 stored in the attic space S2 when the outside air OA introduced into the attic space S2 is heated by sunlight on the roof surface in the attic space S2.

[0024] The outside air introduction duct 51 is provided with an air filter 53 for collecting dust and the like contained in the outside air OA introduced into the attic space S2 from the upstream side in the air flow direction, an air supply fan 54 for supplying the outside air OA to the attic space S2, and an air volume adjustment damper 55 for adjusting the air volume of the outside air OA supplied to the attic space S2.

[0025] The exhaust duct 52 is provided with a temperature detector 56 for detecting the temperature of the air in the attic space S2 from the upstream side in the air flow direction, an exhaust fan 57 for discharging the air heated by the waste heat of the attic space S2 from the attic space S2, and an exhaust motor damper 58 for opening and closing the exhaust duct 52 to intermittently discharge the air from the attic space S2 to the outside through the exhaust duct 52. Further, in the duct portion between the exhaust fan 57 and the motor damper 58 in the exhaust duct 52, a reheating outside air introduction duct 60 as a reheating outside air introduction portion that branches off from this duct portion and guides the air in the attic space S2 to the reheating portions 13 of the respective air conditioners 10 as reheating outside air is provided.

[0026] The reheating outside air introduction duct 60 is provided with a reheating outside air supply motor damper 61 for opening and closing the reheating outside air introduction duct 60 to intermittently supply the reheating outside air from the attic space S2 to the reheating portions 13 of the respective air conditioners 10 through the reheating outside air introduction duct 60 from the upstream side in the air flow direction, and a plurality of reheating outside air volume adjustment portions 62 for adjusting the air volume of the reheating outside air introduced into the reheating portions 13 of the respective air conditioners 10 in the reheating outside air introduction duct 60 for each reheating portion 13. A variable air volume control device (VAV) is adopted for the reheating outside air volume adjustment portion 62.

[0027] The air conditioning system exemplified in this embodiment is provided with a control unit 70 that comprehensively controls its operation. When a request for starting or ending air conditioning, or changing the set temperature or operation mode, etc., is made by a user's operation of an air conditioning remote controller (not shown), the control unit 70 controls the operation of the air conditioning system in response to these requests.

[0028] For example, when a cooling request occurs due to an operation of the air conditioning remote controller or the like, the control unit 70 executes supply air temperature control based on the temperature of the conditioned air SA detected by the supply air temperature detector 31 in response to the cooling request. Also, when a dehumidification request occurs due to an operation of the air conditioning remote controller or the like, the control unit 70 executes dehumidification reheating control based on the temperature of the conditioned air SA (supply air temperature) detected by the supply air temperature detector 31 and the dew point temperature (supply air dew point temperature) in response to the dehumidification request.

[0029] In the supply air temperature control, the control unit 70 performs proportional control of the flow rate adjustment valve 15 based on the detected temperature of the supply air temperature detector 31 so that the temperature of the conditioned air SA detected by the supply air temperature detector 31 becomes the set value.

[0030] Incidentally, in the above control, the return air motor damper 44 is opened as necessary, and return air RA is supplied to the air conditioner 10 through the first return air duct 42. Also, the damper opening degree of the outside air volume adjustment unit 21 and the damper opening degree of the exhaust air volume adjustment unit 41 are controlled so that the exhaust air volume at the exhaust air volume adjustment unit 41 becomes the air volume corresponding to the outside air volume at the outside air volume adjustment unit 21.

[0031] In the dehumidification reheating control, the control unit 70 performs dehumidification control based on the dew point temperature of the conditioned air SA detected by the supply air temperature detector 31, reheating control based on the temperature of the conditioned air SA detected by the supply air temperature detector 31, and the like.

[0032] Regarding the dehumidification and reheating control of the control unit 70, the control unit 70 first performs, as shown in FIG. 6, proportional control of the flow rate adjustment valve 15 to adjust the flow rate of the chilled water CW supplied to the cooling and dehumidifying unit 12 based on the dew point temperature (supply air dew point temperature) of the conditioned air SA detected by the supply air temperature detector 31 so that the dew point temperature becomes the set value SP corresponding to the target humidity as a dehumidification control.

[0033] Specifically, for example, as shown in FIG. 6, when the dew point temperature (supply air dew point temperature) of the conditioned air SA detected by the supply air temperature detector 31 is higher than the set value SP (to the right of the set value SP in FIG. 6), the opening degree of the flow rate adjustment valve 15 is increased according to the difference between the set value SP and the dew point temperature of the conditioned air SA, and the larger the difference, the larger the opening degree of the flow rate adjustment valve 15, and the flow rate of the chilled water CW supplied to the cooling and dehumidifying unit 12 of the air conditioner 10 is increased.

[0034] Conversely, when the dew point temperature (supply air dew point temperature) of the conditioned air SA detected by the supply air temperature detector 31 is lower than the set value SP (to the left of the set value SP in FIG. 6), the opening degree of the flow rate adjustment valve 15 is decreased according to the difference between the set value SP and the dew point temperature of the conditioned air SA, and the larger the difference, the smaller the opening degree of the flow rate adjustment valve 15, and the flow rate of the chilled water CW supplied to the cooling and dehumidifying unit 12 of the air conditioner 10 is decreased.

[0035] By this dehumidification control, the temperature of the conditioned air (dehumidified air) SA becomes in a subcooled state with respect to the set value SP corresponding to the target temperature, and a reheating requirement to heat the subcooled conditioned air SA according to the set value (target temperature) occurs.

[0036] When a reheating requirement occurs, the control unit 70 performs reheating control to heat the conditioned air (dehumidified air) SA in the reheating unit 13 based on the temperature of the conditioned air SA detected by the supply air temperature detector 31 so that the temperature becomes the set value according to the reheating requirement.

[0037] In the reheating control, the control unit 70 first determines whether the temperature of the air in the attic space S2 is within the temperature range available for reheating control based on the detected temperature of the temperature detector 56. If the temperature of the air is within the temperature range, the reheating control state of the air conditioning system becomes the waste heat utilization reheating state shown in FIG. 2, and the air in the attic space S2 becomes the outside air for reheating. Only this outside air for reheating is supplied to the reheating section 13 of the air conditioner 10 to reheat the conditioned air (dehumidified air) SA. Then, the motor dampers 44, 58, 61 and the air volume adjustment sections 21, 41, 45, 62 are controlled accordingly.

[0038] In the waste heat utilization reheating state shown in FIG. 2, the control unit 70 closes the return air motor damper 44, thereby stopping the supply of return air to the air conditioner 10 through the first return air duct 42. Also, the control unit 70 controls the damper opening degree at the return air volume adjustment section 45 to the fully closed state, so that the return air volume at the return air volume adjustment section 45 becomes zero. Furthermore, the control unit 70 closes the exhaust motor damper 58 in the ventilation device 50 and opens the outside air supply motor damper 61 for reheating, thereby switching the state of the ventilation device 50 from the exhaust state of discharging the air in the attic space S2 to the outside as the exhaust air EA to the supply state of supplying the air in the attic space S2 as the outside air for reheating to the reheating section 13 of the air conditioner 10.

[0039] In the supply state of the ventilation device 50, the control unit 70 operates the supply air fan 54 and the exhaust fan 57 of the ventilation device 50, and controls the damper opening degree of the outside air volume adjustment section 62 for reheating based on the detected temperature of the supply air temperature detector 31, so that the air in the attic space S2 is supplied to the reheating section 13 of the air conditioner 10 as the outside air for reheating. Also, the control unit 70 controls the damper opening degrees of the outside air volume adjustment section 21 and the exhaust air volume adjustment section 41, and adjusts the exhaust air volume at the exhaust air volume adjustment section 41 to be an air volume corresponding to the outside air volume at the outside air volume adjustment section 21 and the outside air volume for reheating at the outside air volume adjustment section 62 for reheating.

[0040] In the waste heat utilization reheating state shown in Fig. 2, as shown in Fig. 7(a), the control unit 70 controls the damper opening degree of the outside air volume adjustment unit 62 for reheating based on the temperature of the air-conditioning air SA (supply air temperature) detected by the supply air temperature detector 31 so that the temperature becomes the set value SP, and adjusts the air volume of the outside air for reheating supplied to the reheating unit 13 of the air conditioner 10.

[0041] Specifically, for example, in the waste heat utilization reheating state shown in Figs. 2 and 7(a), when the temperature of the air-conditioning air SA (supply air temperature) detected by the supply air temperature detector 31 is lower than the set value SP (to the left of the set value SP in Fig. 7(a)), the damper opening degree of the outside air volume adjustment unit 62 for reheating is increased according to the difference between the set value SP and the temperature of the air-conditioning air SA, and the larger the difference, the larger the damper opening degree, so as to increase the air volume of the outside air for reheating supplied from the attic space S2 to the reheating unit 13 of the air conditioner 10.

[0042] Conversely, when the temperature of the air-conditioning air SA (supply air temperature) detected by the supply air temperature detector 31 is higher than the set value SP (to the right of the set value SP in Fig. 7(a)), the damper opening degree of the outside air volume adjustment unit 62 for reheating is decreased according to the difference between the set value SP and the temperature of the air-conditioning air SA, and the larger the difference, the smaller the damper opening degree, so as to decrease the air volume of the outside air for reheating supplied from the attic space S2 to the reheating unit 13 of the air conditioner 10.

[0043] And as long as it is possible to maintain the temperature of the air-conditioning air SA (supply air temperature) detected by the supply air temperature detector 31 at the set value SP by adjusting the air volume of the outside air for reheating in this way, the waste heat utilization reheating state is continued.

[0044] That is, in the waste heat utilization reheating state shown in Fig. 2, the air heated by the waste heat of the attic space S2 in the attic space S2 is led to the reheating unit 13 as the outside air for reheating, and in the reheating unit 13, the dehumidified air cooled and dehumidified by the cooling and dehumidifying unit 12 is mixed to reheat the dehumidified air (air-conditioning air SA).

[0045] Thus, in the waste heat utilization reheating state, by using the air heated by the waste heat in the attic space S2 as the outside air for reheating, when this outside air is mixed with the dehumidified air in the reheating section 13 and the dehumidified air is reheated, the waste heat possessed by the outside air is effectively utilized. As a result, even when the outside air temperature is low, the reheating of the dehumidified air by the outside air OA can be performed well, and the reheated dehumidified air can be supplied as the air-conditioning air SA that satisfies the required temperature to the air-conditioning target space S1.

[0046] Moreover, since the outside air OA supplied as the air-conditioning air SA to the air-conditioning target space S1 is divided into the outside air for cooling and dehumidifying and the outside air for reheating, while ensuring the amount of outside air required for ventilation, the amount of outside air volume to be cooled and dehumidified in the cooling and dehumidifying section 12 can be reduced. As a result, it is possible to use an energy-saving type with a low cooling capacity as the cooling and dehumidifying section 12, and the amount of energy required for reheating can be reduced.

[0047] In the reheating control, the control unit 70 preferentially implements the waste heat utilization reheating state shown in FIG. 2 as described above. However, in this waste heat utilization reheating state, for example, when the amount of heat possessed by the air in the attic space S2 decreases, or when the set value SP is changed to the higher side, only the control of the outside air volume adjustment unit 62 for reheating based on the detected temperature of the supply air temperature detector 31 cannot make the temperature (supply air temperature) of the air-conditioning air SA detected by the supply air temperature detector 31 reach the set value SP because it becomes lower than the set value SP. In this case, the reheating control state of the air-conditioning system is switched from the waste heat utilization reheating state shown in FIG. 2 to the combined reheating state of the outside air for reheating and the return air shown in FIG. 3 by controlling the return air volume adjustment unit 45.

[0048] As shown in Fig. 3, in the state of reheating using outside air and return air together for reheating, in addition to the outside air for reheating from the attic space S2, the return air RA from the air-conditioned space S1 is supplied to the reheating section 13 of the air conditioner 10. As shown in Fig. 7(b), the control unit 70, based on the temperature of the conditioned air SA (supply air temperature) detected by the supply air temperature detector 31, controls the damper opening of the return air volume adjustment section 45 while maintaining the damper opening of the outside air volume adjustment section 62 for reheating in the fully open state so that the temperature becomes the set value SP, and adjusts the volume of the return air supplied to the reheating section 13 of the air conditioner 10 in a state where the volume of the outside air for reheating supplied to the reheating section 13 is maximized.

[0049] Specifically, for example, in the state of reheating using outside air and return air together for reheating shown in Figs. 3 and 7(b), when the temperature of the conditioned air SA (supply air temperature) detected by the supply air temperature detector 31 is lower than the set value SP (to the left of the set value SP in Fig. 7(b)), while maintaining the damper opening of the outside air volume adjustment section 62 for reheating in the fully open state, according to the difference between the set value SP and the temperature of the conditioned air SA, the larger the difference, the larger the damper opening of the return air volume adjustment section 45, and the volume of the return air RA supplied from the air-conditioned space S1 to the reheating section 13 of the air conditioner 10 is increased.

[0050] Conversely, when the temperature of the conditioned air SA (supply air temperature) detected by the supply air temperature detector 31 is higher than the set value SP (to the right of the set value SP in Fig. 7(b)), while maintaining the damper opening of the outside air volume adjustment section 62 for reheating in the fully open state, according to the difference between the set value SP and the temperature of the conditioned air SA, the larger the difference, the smaller the damper opening of the return air volume adjustment section 45, and the volume of the return air RA supplied from the air-conditioned space S1 to the reheating section 13 of the air conditioner 10 is decreased.

[0051] Thus, in the reheat state using outside air and return air for reheat, in addition to the outside air for reheat from the attic space S2, the return air RA from the air-conditioned space S1 can also be mixed with the dehumidified air in the reheating section 13 for reheat. As a result, for reheating the dehumidified air in the reheating section 13, in addition to the heat held by the outside air for reheat (waste heat in the attic space S2), the heat held by the return air RA from the air-conditioned space S1 can also be effectively utilized, and the reheating of the dehumidified air in the reheating section 13 can be performed better.

[0052] And as described above, in the reheat control, the control unit 70 controls so that the outside air for reheat from the attic space S2 is supplied to the reheating section 13 prior to the return air RA from the air-conditioned space S1. Thus, while efficiently reheating the dehumidified air in the reheating section 13, when the amount of heat held by the outside air for reheat is insufficient, the shortage can be compensated by the heat held by the return air RA from the air-conditioned space S1, and the reheating of the dehumidified air in the reheating section 13 can be stably performed.

[0053] As described above, according to the air conditioning system exemplified in the present embodiment, while appropriately supplying the conditioned air SA that satisfies the required temperature for the air-conditioned space S1, it is possible to preferably promote energy saving by eliminating or reducing the size of the heat source for reheat, that is, by reducing or miniaturizing the heat source for reheat.

[0054] In the reheat control, if the temperature of the air in the attic space S2 is not within the temperature range available for reheat control, the control unit 70 controls each motor damper 44, 58, 61 and each air volume adjustment unit 21, 41, 45, 62 so that the reheat control state of the air conditioning system becomes the reheat state using return air shown in FIG. 4, and only the return air RA from the air-conditioned space S1 is supplied to the reheating section 13 of the air conditioner 10 for reheat.

[0055] In the return air utilization and reheating state shown in FIG. 4, the control unit 70 closes the motor damper 44 for return air, thereby stopping the supply of return air to the air conditioner 10 through the first return air duct 42. Further, the control unit 70 opens the motor damper 58 for exhaust in the ventilation device 50 and closes the motor damper 61 for supplying reheated outside air, thereby changing the state of the ventilation device 50 from the supply state in which the air in the attic space S2 is supplied to the reheating section 13 of the air conditioner 10 as reheated outside air to the supply stop state in which the air in the attic space S2 is not supplied to the reheating section 13 of the air conditioner 10.

[0056] Then, the control unit 70 controls the damper opening degree of the return air volume adjustment unit 45 based on the detected temperature of the supply air temperature detector 31, so that only the return air RA from the air-conditioned space S1 is supplied to the reheating section 13 of the air conditioner 10 for reheating. Further, the control unit 70 controls the damper opening degree of the outside air volume adjustment unit 21 and the damper opening degree of the exhaust air volume adjustment unit 41 so that the exhaust air volume at the exhaust air volume adjustment unit 41 is adjusted to be an air volume corresponding to the outside air volume at the outside air volume adjustment unit 21.

[0057] In the return air utilization and reheating state shown in FIG. 4, as shown in FIG. 7(c), the control unit 70 controls the damper opening degree of the return air volume adjustment unit 45 based on the temperature of the conditioned air SA (supply air temperature) detected by the supply air temperature detector 31 so that the temperature becomes the set value SP, and adjusts the return air volume supplied to the reheating section 13 of the air conditioner 10.

[0058] Specifically, for example, in the return air utilization and reheating state shown in FIGS. 4 and 7(c), when the temperature of the conditioned air SA (supply air temperature) detected by the supply air temperature detector 31 is lower than the set value SP (to the left of the set value SP in FIG. 7(c)), the damper opening degree of the return air volume adjustment unit 45 is increased according to the difference between the set value SP and the temperature of the conditioned air SA, and the larger the difference, the larger the return air volume RA supplied from the air-conditioned space S1 to the reheating section 13 of the air conditioner 10 is increased.

[0059] Conversely, when the temperature of the conditioned air SA detected by the supply air temperature detector 31 (supply air temperature) is higher than the set value SP (to the right of the set value SP in Fig. 7 (c)), according to the difference between the set value SP and the temperature of the conditioned air SA, the larger the difference, the smaller the damper opening degree of the return air volume adjustment unit 45, and the air volume of the return air RA supplied from the air conditioning target space S1 to the reheating unit 13 of the air conditioner 10 is decreased.

[0060] In this way, in the reheating control, when the temperature of the air in the attic space S2 is out of the temperature range available for reheating control, and the air in the attic space S2 cannot be used for reheating the dehumidified air in the reheating unit 13, the return air RA from the air conditioning target space S1 can be mixed with the dehumidified air in the reheating unit 13 for reheating. Thereby, in a situation where the air in the attic space S2 cannot be used as the outside air for reheating, the retained heat of the return air RA from the air conditioning target space S1 can be effectively utilized for reheating the dehumidified air in the reheating unit 13, and the dehumidified air after reheating can be supplied to the air conditioning target space S1 as the conditioned air SA that satisfies the required temperature.

[0061] When the temperature of the air in the attic space S2 detected by the temperature detector 56 described above reaches a predetermined temperature in a state where the above-described reheating request has not occurred, the control unit 70 switches the state of the ventilation device 50 to the exhaust state as shown in Fig. 5. And in this exhaust state, the control unit 70 opens the motor damper 58 for exhaust and closes the motor damper 61 for supplying outside air for reheating, and then operates the supply air fan 54 and the exhaust fan 57 of the ventilation device 50 at rated operation, thereby ventilating the attic space S2.

[0062] When the above-described reheating request occurs during the ventilation of the attic space S2 like this, the control unit 70 switches the state of the ventilation device 50 from the exhaust state to the supply state described above. And in this supply state, the control unit 70 controls the supply air fan 54 and the exhaust fan 57 of the ventilation device 50 so that their supply air volume and exhaust air volume become the total air volume of each outside air volume adjustment unit 62 for reheating, whereby the air in the attic space S2 is supplied to the reheating unit 13 of each air conditioner 10 as the outside air for reheating.

[0063] 〔Alternative Embodiment〕 An alternative embodiment of the present invention will be described. Note that the configurations of the respective alternative embodiments described below are not limited to being applied individually, and can also be applied in combination with the configurations of the above-described embodiment and other alternative embodiments.

[0064] (1) In the above-described embodiment, as the air-conditioning system, an example was given in which a plurality of air conditioners 10 are provided in parallel, but it is not limited thereto, and an air-conditioning system provided with one air conditioner 10 may be used.

[0065] (2) In the above-described embodiment, as the air-conditioning system, by providing the second return air duct 43 and the return air volume adjustment unit 45, the reheating control state of the air-conditioning system is configured to be switchable between the waste heat utilization reheating state and the outside air / return air combined reheating state for reheating. However, it is not limited thereto. For example, it may be configured to reheat the dehumidified air only in the waste heat utilization reheating state without providing the second return air duct 43 and the return air volume adjustment unit 45.

[0066] (3) In the above-described embodiment, as the air-conditioning system, an example was given in which the reheating control state is configured to be switchable between the waste heat utilization reheating state and the outside air / return air combined reheating state for reheating. However, it is not limited thereto. For example, instead of or in addition to the second return air duct 43 and the return air volume adjustment unit 45, an auxiliary heating unit composed of a heating coil or the like may be provided on the reheating unit 13 of the air conditioner 10 or on the downstream side in the air flow direction from this, and used for reheating the dehumidified air.

Explanation of Reference Numerals

[0067] 12 Cooling and dehumidifying unit 13 Reheating unit 20 Outside air introduction unit 43 Return air introduction unit 45 Return air volume adjustment unit 60 Outside air introduction unit for reheating 62 Outside air volume adjustment unit for reheating 70 Control unit OA Outdoor air RA Return air S1 Air-conditioned space S2 Attic space

Claims

1. An air conditioning system comprising a cooling and dehumidifying unit that cools and dehumidifies outside air introduced from an outside air introduction unit, and a reheating unit that reheats the dehumidified air cooled and dehumidified by the cooling and dehumidifying unit, wherein a reheating outside air introduction unit is provided that guides air heated by waste heat in the attic space as reheating outside air to the reheating unit in the attic space, and in the reheating unit, the reheating outside air introduced from the reheating outside air introduction unit is mixed with the dehumidified air cooled and dehumidified by the cooling and dehumidifying unit to reheat the dehumidified air.

2. The air conditioning system according to claim 1, further comprising a return air introduction unit that guides return air from the air-conditioned space to the reheating unit, and in the reheating unit, the return air introduced from the return air introduction unit is mixed with the dehumidified air cooled and dehumidified by the cooling and dehumidifying unit to reheat the dehumidified air.

3. A reheating outside air volume adjustment unit that adjusts the volume of reheating outside air introduced into the reheating unit by the reheating outside air introduction unit, a return air volume adjustment unit that adjusts the volume of return air introduced into the reheating unit by the return air introduction unit, and a control unit that controls the reheating outside air volume adjustment unit and the return air volume adjustment unit so that the reheating outside air is supplied to the reheating unit prior to the return air.

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