Dew condensation prevention system and building

Abstract

This dew condensation prevention system comprises an air supply device, a control device, an attic temperature sensor, and an attic humidity sensor. The air supply device supplies indoor air air-conditioned by an air conditioner to an attic space. The control device controls the air supply device. The attic temperature sensor measures the temperature (Tas) in the vicinity of the rear surface of a ceiling. The attic humidity sensor measures humidity in the vicinity of the rear surface of the ceiling. The control device causes the air supply device to operate when the temperature (Tas) in the vicinity of the rear surface of the ceiling is equal to or lower than a dew point temperature (Tad) in the vicinity of the rear surface of the ceiling, which is calculated from the temperature (Tas) and humidity in the vicinity of the rear surface of the ceiling.

Description

Dew prevention system and building

[0001] The present disclosure relates to a dew prevention system and a building.

[0002] It is desirable to suppress dew formation in the ceiling space of a building. For example, Patent Document 1 discloses a ventilation device that suppresses dew formation on the surface of a duct disposed in the ceiling space.

[0003] Japanese Unexamined Patent Application Publication No. 2023 - 111129

[0004] In summer, hot and humid outside air enters the ceiling space. Also, in summer, due to the cooling operation of an air conditioner for air - conditioning the room, the temperature of the ceiling decreases. When the outside air that has entered the ceiling space is cooled by the ceiling, there is a risk of dew formation in the ceiling space.

[0005] (1) The dew prevention system for solving the above problems includes an air supply device that supplies the air in the room air - conditioned by an air conditioner to the ceiling space, a control device that controls the air supply device, a ceiling - back temperature sensor that measures the temperature near the back surface of the ceiling, and a ceiling - back humidity sensor that measures the humidity near the back surface of the ceiling. The control device operates the air supply device when the temperature near the back surface of the ceiling is below the dew point temperature near the back surface of the ceiling calculated from the temperature and humidity near the back surface of the ceiling.

[0006] According to this configuration, when the temperature near the back surface of the ceiling is below the dew point temperature near the back surface of the ceiling, that is, in a situation where dew formation may occur in the ceiling space, the cold air in the room air - conditioned by the cooling operation of the air conditioner is supplied to the ceiling space by the air supply device. As a result, the temperature difference between the ceiling space and the room becomes smaller, so that dew formation in the ceiling space can be suppressed.

[0007] (2) In the dew prevention system of (1) above, it includes an indoor temperature sensor that measures the temperature of the room and an indoor humidity sensor that measures the humidity of the room. The control device operates the air supply device when the temperature near the back surface of the ceiling is below the dew point temperature near the back surface of the ceiling and the dew point temperature of the room calculated from the temperature and humidity of the room is below the dew point temperature near the back surface of the ceiling.

[0008] With this configuration, indoor air with a dew point temperature below the dew point temperature near the back surface of the ceiling is supplied to the space above the ceiling, thereby further suppressing condensation in the space above the ceiling. (3) In the condensation prevention system of (1) or (2) above, a space above ceiling exhaust device is provided to discharge the air in the space above the ceiling to the outside, and the control device operates the space above ceiling exhaust device when the temperature near the back surface of the ceiling is below the dew point temperature near the back surface of the ceiling.

[0009] With this configuration, in situations where condensation may occur in the attic space, the air in the attic space is discharged to the outside by the attic exhaust device. By ventilating the attic space with the air supply device and the attic exhaust device, condensation in the attic space can be further suppressed.

[0010] (4) In the condensation prevention system described in (3) above, an indoor exhaust device is provided that directly discharges the indoor air to the outside, and the control device stops the indoor exhaust device when the air supply device and the ceiling exhaust device are in operation, and operates the indoor exhaust device when the air supply device and the ceiling exhaust device are stopped.

[0011] With this configuration, the air supply unit and the ceiling exhaust unit and the indoor exhaust unit are not operated simultaneously, thus reducing energy loss. (5) In the condensation prevention system of (3) or (4) above, the control device stops the air supply unit and the ceiling exhaust unit when the air conditioning unit is stopped.

[0012] With this configuration, the air supply system and the ceiling exhaust system are also stopped when the air conditioning system is shut down, thus reducing energy loss. In addition, during the summer, the hot and humid indoor air that is not conditioned is not supplied to the ceiling space by the cooling operation of the air conditioning system, thus suppressing condensation in the ceiling space when the cooling operation of the air conditioning system is stopped.

[0013] (6) In any one of the condensation prevention systems described in (1) to (5) above, the ceiling temperature sensor measures the surface temperature of the back surface of the ceiling as the temperature near the back surface of the ceiling. With this configuration, the temperature near the back surface of the ceiling can be accurately measured.

[0014] (7) In any one of the condensation prevention systems described in (1) to (5) above, the space above the ceiling is provided with an insulating material or a sound-absorbing material as a ceiling space component, and the ceiling space temperature sensor measures the temperature of the space above the back surface of the ceiling and below the ceiling space component as the temperature near the back surface of the ceiling.

[0015] (8) A building that solves the above problems is equipped with one of the condensation prevention systems described in (1) to (7) above. With this configuration, when the temperature near the back surface of the ceiling is below the dew point temperature near the back surface of the ceiling, that is, when condensation can occur in the space above the ceiling, the cool indoor air conditioned by the cooling operation of the air conditioning system is supplied to the space above the ceiling by the air supply device. As a result the temperature difference between the space above the ceiling and the room is reduced, and condensation in the space above the ceiling can be suppressed.

[0016] (9) In the building described in (8) above, the condensation prevention system is installed in the ceiling space of the top floor. With this configuration, in the summer, the temperature in the ceiling space of the top floor tends to be higher than the temperature in the ceiling spaces of the other floors. Therefore, it is particularly effective to suppress condensation in the ceiling space of the top floor by installing a condensation prevention system.

[0017] The condensation prevention system and building described herein can suppress condensation in the space above the ceiling.

[0018] This is a schematic diagram of the condensation prevention system. This is an enlarged view of the condensation prevention system. This is a configuration diagram of the condensation prevention system. This is a flowchart showing the control of the attic ventilation system performed by the control device. This is a timing chart showing changes in the dew point temperature near the underside of the ceiling, the operating status of the attic ventilation system, the operating status of the indoor ventilation system, and the operating status of the air conditioning system.

[0019] The condensation prevention system 20 and building 10 of this embodiment will be described with reference to Figures 1 to 5. The building 10 is, for example, a detached house, an apartment building, an accommodation facility, an office, a commercial building, or an office building. The building 10 of this embodiment is a steel frame structure (S structure).

[0020] As shown in Figure 1, the building 10 is equipped with a condensation prevention system 20. In this embodiment, the condensation prevention system 20 is installed in the space above the ceiling A of the top floor. The space above the ceiling A of the top floor is the space enclosed by the ceiling 11, roof 12, and exterior wall 13 of the top floor. Outside air enters the space above the ceiling A through gaps in the exterior wall 13. In summer, the outside air entering the space above the ceiling A is hot and humid.

[0021] As shown in Figures 1 and 2, the ceiling 11 has a plurality of furring strips 14 and a ceiling material 15. The plurality of furring strips 14 are arranged in a row with gaps between them. The ceiling material 15 is made of gypsum board. The ceiling material 15 is fixed to the lower surface of the plurality of furring strips 14. The upper surface of the ceiling material 15 constitutes the back surface 11a of the ceiling 11. The back surface 11a of the ceiling 11 is the surface of the ceiling 11 opposite to the interior R side.

[0022] An insulating material 16, which serves as an attic installation member, is placed on top of multiple ceiling joists 14. Therefore, the attic space A is provided with the insulating material 16 as an attic installation member. The insulating material 16 in this embodiment is made of glass wool or rock wool. The insulating material 16 is installed so as to divide the attic space A vertically. Although not shown, the portion of the insulating material 16 that is not supported by the ceiling joists 14 may sag downwards.

[0023] <Condensation Prevention System> As shown in Figures 1 and 3, the condensation prevention system 20 includes an air conditioning unit 21, an indoor ventilation unit 22, and an attic ventilation unit 23.

[0024] The air conditioning unit 21 provides air conditioning to the room R based on a command from the user. The air conditioning unit 21 has an indoor unit 21a. In this embodiment, the indoor unit 21a is installed on the ceiling 11. The air conditioning unit 21 is configured to be capable of cooling operation. When the air conditioning unit 21 is in cooling operation, the temperature of the room R decreases.

[0025] The indoor ventilation system 22 is provided separately from a 24-hour ventilation system (not shown) that continuously ventilates the indoor R. The indoor ventilation system 22 provides localized ventilation of the indoor R. The indoor ventilation system 22 includes an air intake (not shown), an indoor exhaust system 22a, and a duct 22b. Outdoor air D is supplied to the indoor R from the air intake. The indoor exhaust system 22a is composed of a fan. The indoor exhaust system 22a is installed in the ceiling 11. In this embodiment, the indoor exhaust system 22a is located away from the air intake. The duct 22b is installed in the space above the ceiling A. The first end of the duct 22b is connected to the indoor R. The second end of the duct 22b is connected to the outdoor D. When the indoor exhaust system 22a is operated, the air in the indoor R is discharged to the outdoor D via the duct 22b. The indoor exhaust system 22a directly discharges the air from the indoor R to the outdoor D.

[0026] The attic ventilation device 23 ventilates the attic space A. The attic ventilation device 23 has an air supply device 23a and an attic exhaust device 23b. The air supply device 23a supplies air from the room R to the attic space A. As described above, the room R is air-conditioned by the air conditioning device 21. Therefore, the air supply device 23a can supply air from the room R, which has been air-conditioned by the air conditioning device 21, to the attic space A. The air supply device 23a is composed of a fan. The air supply device 23a is installed in the ceiling 11. In this embodiment, the air supply device 23a is located near the indoor unit 21a. In this embodiment, the air supply device 23a is located away from the attic exhaust device 23b, more specifically, on the opposite side of the indoor unit 21a from the attic exhaust device 23b. When the air supply device 23a is operated, air from the room R is supplied to the attic space A. In this embodiment, indoor air R is supplied to the space located above the insulation material 16 in the ceiling space A.

[0027] The attic exhaust device 23b discharges air from the attic space A to the outdoors D. The attic exhaust device 23b is composed of a fan. The attic exhaust device 23b is installed in the attic space A. When the attic exhaust device 23b is operated, the air from the attic space A is discharged to the outdoors D. In this embodiment, the air in the space above the insulation material 16 in the attic space A is discharged to the outdoors D. The amount of exhaust from the attic space A to the outdoors D by the indoor exhaust device 22a is less than or equal to the amount of air supplied from the indoor R to the attic space A by the air supply device 23a.

[0028] As shown in Figures 2 and 3, the condensation prevention system 20 includes a ceiling temperature sensor 24, a ceiling humidity sensor 25, a room temperature sensor 26, and a room humidity sensor 27. Note that in Figure 1, the ceiling temperature sensor 24, ceiling humidity sensor 25, room temperature sensor 26, and room humidity sensor 27 are not shown.

[0029] In this embodiment, the attic temperature sensor 24 and the attic humidity sensor 25 are attached to the back surface 11a of the ceiling 11. The attic temperature sensor 24 and the attic humidity sensor 25 are located between adjacent ceiling joists 14. The attic temperature sensor 24 measures the temperature Tas near the back surface 11a of the ceiling 11. In this embodiment, the attic temperature sensor 24 measures the surface temperature of the back surface 11a of the ceiling 11 as the temperature Tas near the back surface 11a of the ceiling 11. The attic humidity sensor 25 measures the humidity near the back surface 11a of the ceiling 11.

[0030] The indoor temperature sensor 26 and the indoor humidity sensor 27 are installed in room R. The indoor temperature sensor 26 measures the temperature of room R. The indoor humidity sensor 27 measures the humidity of room R.

[0031] As shown in Figure 3, the condensation prevention system 20 includes a control device 28. The control device 28 includes a processor and a memory unit (not shown). The processor is, for example, a CPU (Central Processing Unit) or a DSP (Digital Signal Processor). The memory unit includes RAM (Random Access Memory) and ROM (Read Only Memory). The memory unit stores program code or instructions configured to cause the processor to execute processing. The memory unit, i.e., the computer-readable medium, includes any available medium that can be accessed by a general-purpose or dedicated computer. The control device 28 may be composed of hardware circuits such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array). The control device 28, which is a processing circuit, may include one or more processors that operate according to a computer program, one or more hardware circuits such as an ASIC or FPGA, or a combination thereof.

[0032] The control device 28 obtains the temperature Tas near the back surface 11a of the ceiling 11 from the ceiling space temperature sensor 24. The control device 28 obtains the humidity near the back surface 11a of the ceiling 11 from the ceiling space humidity sensor 25. The control device 28 calculates the dew point temperature Tad near the back surface 11a of the ceiling 11 from the temperature Tas and humidity near the back surface 11a of the ceiling 11. The control device 28 obtains the temperature of the room R from the room temperature sensor 26. The control device 28 obtains the humidity of the room R from the room humidity sensor 27. The control device 28 calculates the dew point temperature Trd of the room R from the temperature and humidity of the room R.

[0033] The control device 28 controls the ceiling ventilation device 23 and the indoor ventilation device 22. The control device 28 in this embodiment is configured to receive an operation stop signal indicating that the operation of the air conditioning device 21 has stopped.

[0034] <Control of the Ceiling Ventilation System> The control of the ceiling ventilation system 23, which is performed by the control device 28, will now be described. As shown in Figure 4, the control device 28 determines whether the temperature Tas near the back surface 11a of the ceiling 11 is less than or equal to the dew point temperature Tad near the back surface 11a of the ceiling 11 (step S1). If the temperature Tas near the back surface 11a of the ceiling 11 is less than or equal to the dew point temperature Tad near the back surface 11a of the ceiling 11 (YES in step S1), the control device 28 determines whether the dew point temperature Trd of the room R is less than or equal to the dew point temperature Tad near the back surface 11a of the ceiling 11 (step S2). If the temperature Tas near the back surface 11a of the ceiling 11 is not less than or equal to the dew point temperature Tad near the back surface 11a of the ceiling 11 (NO in step S1), the control device 28 terminates the series of processes.

[0035] If the dew point temperature Trd in the room R is less than or equal to the dew point temperature Tad near the back surface 11a of the ceiling 11 (YES in step S2), the control device 28 operates the ceiling space ventilation device 23 (step S3). In this embodiment, the control device 28 operates both the air supply device 23a and the ceiling space exhaust device 23b. If the dew point temperature Trd in the room R is not less than or equal to the dew point temperature Tad near the back surface 11a of the ceiling 11 (NO in step S2), the control device 28 terminates the series of processes.

[0036] <Example of operation of the condensation prevention system> As shown in Figure 5, when the temperature Tas near the back surface 11a of the ceiling 11 falls below the dew point temperature Tad near the back surface 11a of the ceiling 11, the control device 28 operates the ceiling ventilation device 23. In this embodiment, the control device 28 operates the ceiling ventilation device 23 for a predetermined time T. For example, the control device 28 operates the ceiling ventilation device 23 for 10 minutes. The control device 28 operates the ceiling ventilation device 23 each time the temperature Tas near the back surface 11a of the ceiling 11 falls below the dew point temperature Tad near the back surface 11a of the ceiling 11.

[0037] In this embodiment, the control device 28 stops the indoor exhaust device 22a of the indoor ventilation device 22 at the same time as the operation of the attic ventilation device 23 starts. Therefore, the indoor ventilation device 22 is stopped while the attic ventilation device 23 is operating. Also, the control device 28 starts the indoor exhaust device 22a of the indoor ventilation device 22 at the same time as the operation of the attic ventilation device 23 stops. Therefore, the indoor exhaust device 22a operates while the attic ventilation device 23 is stopped.

[0038] As described above, the control device 28 is configured to receive a stop signal from the air conditioning unit 21. In this embodiment, when the control device 28 receives a stop signal from the air conditioning unit 21 while the ceiling ventilation unit 23 is operating, it stops the ceiling ventilation unit 23. Therefore, while the air conditioning unit 21 is stopped, the ceiling ventilation unit 23 is also stopped.

[0039] Furthermore, if the control device 28 stops the operation of the ceiling ventilation system 23 due to a stop signal from the air conditioning system 21, it will not operate the indoor ventilation system 22 even if the ceiling ventilation system 23 is stopped. Therefore, while the air conditioning system 21 is stopped, the indoor ventilation system 22 will also be stopped.

[0040] [Operation of this Embodiment] The operation of this embodiment will now be described. The condensation prevention system 20 includes a ceiling space ventilation device 23, a control device 28, a ceiling space temperature sensor 24, and a ceiling space humidity sensor 25. The ceiling space ventilation device 23 has an air supply device 23a and a ceiling space exhaust device 23b. The air supply device 23a supplies air from the room R, which has been conditioned by the air conditioning device 21, to the ceiling space A. The ceiling space exhaust device 23b discharges the air from the ceiling space A to the outside D. The control device 28 controls the ceiling space ventilation device 23. The ceiling space temperature sensor 24 measures the temperature Tas near the back surface 11a of the ceiling 11. The ceiling space humidity sensor 25 measures the humidity near the back surface 11a of the ceiling 11. The control device 28 operates the ceiling ventilation device 23 when the temperature Tas near the back surface 11a of the ceiling 11 is less than or equal to the dew point temperature Tad near the back surface 11a of the ceiling 11, which is calculated from the temperature Tas and humidity near the back surface 11a of the ceiling 11. In other words, the control device 28 operates the ceiling ventilation device 23 when conditions are such that condensation may occur in the ceiling space A.

[0041] The air supply device 23a supplies the air in the indoor space R at a low temperature conditioned by the cooling operation of the air conditioner 21 to the ceiling space A. Further, the ceiling exhaust device 23b discharges the hot and humid air that has entered the ceiling space A to the outdoors D. Since the ceiling space A is ventilated by the ceiling ventilation device 23, the temperature difference between the ceiling space A and the indoor space R becomes small, and thus condensation in the ceiling space A is suppressed.

[0042] [Effects of the Present Embodiment] The effects of the present embodiment will be described. (1) The dew condensation prevention system 20 includes an air supply device 23a, a control device 28, a ceiling temperature sensor 24, and a ceiling humidity sensor 25. The air supply device 23a supplies the air in the indoor space R conditioned by the air conditioner 21 to the ceiling space A. The control device 28 controls the air supply device 23a. The ceiling temperature sensor 24 measures the temperature Tas near the back surface 11a of the ceiling 11. The ceiling humidity sensor 25 measures the humidity near the back surface 11a of the ceiling 11. When the temperature Tas near the back surface 11a of the ceiling 11 is not more than the dew point temperature Tad near the back surface 11a of the ceiling 11 calculated from the temperature Tas and humidity near the back surface 11a of the ceiling 11, the control device 28 operates the air supply device 23a.

[0043] According to this configuration, in a situation where condensation may occur in the ceiling space A, the air in the indoor space R at a low temperature conditioned by the cooling operation of the air conditioner 21 is supplied to the ceiling space A by the air supply device 23a. As a result, the temperature difference between the ceiling space A and the indoor space R becomes small, and thus condensation in the ceiling space A can be suppressed.

[0044] (2) The dew condensation prevention system 20 includes an indoor temperature sensor 26 and an indoor humidity sensor 27. The indoor temperature sensor 26 measures the temperature of the indoor space R. The indoor humidity sensor 27 measures the humidity of the indoor space R. When the temperature Tas near the back surface 11a of the ceiling 11 is not more than the dew point temperature Tad near the back surface 11a of the ceiling 11 and the dew point temperature Trd of the indoor space R calculated from the temperature and humidity of the indoor space R is not more than the dew point temperature Tad near the back surface 11a of the ceiling 11, the control device 28 operates the air supply device 23a.

[0045] According to this configuration, since the air in the room R with a dew point temperature Trd not higher than the dew point temperature Tad near the back surface 11a of the ceiling 11 is supplied to the ceiling back space A, condensation in the ceiling back space A can be further suppressed.

[0046] (3) The condensation prevention system 20 includes a ceiling back exhaust device 23b. The ceiling back exhaust device 23b discharges the air in the ceiling back space A to the outdoors D. The control device 28 operates the ceiling back exhaust device 23b when the temperature Tas near the back surface 11a of the ceiling 11 is not higher than the dew point temperature Tad near the back surface 11a of the ceiling 11.

[0047] According to this configuration, in a situation where condensation may occur in the ceiling back space A, the air in the ceiling back space A is discharged to the outdoors D by the ceiling back exhaust device 23b. By ventilating the ceiling back space A by the air supply device 23a and the ceiling back exhaust device 23b, condensation in the ceiling back space A can be further suppressed.

[0048] (4) The condensation prevention system 20 includes an indoor exhaust device 22a. The indoor exhaust device 22a directly discharges the air in the room R to the outdoors D. The control device 28 stops the indoor exhaust device 22a during the operation of the air supply device 23a and the ceiling back exhaust device 23b. The control device 28 operates the indoor exhaust device 22a during the stop of the air supply device 23a and the ceiling back exhaust device 23b.

[0049] According to this configuration, since the air supply device 23a, the ceiling back exhaust device 23b, and the indoor exhaust device 22a are not operated simultaneously, energy loss can be reduced. (5) The control device 28 stops the air supply device 23a and the ceiling back exhaust device 23b during the stop of the air conditioner 21.

[0050] According to this configuration, since the air supply device 23a and the ceiling back exhaust device 23b are also stopped during the stop of the air conditioner 21, energy loss can be reduced. Further, in summer, since the hot and humid air in the room R that is not air-conditioned by the cooling operation of the air conditioner 21 is not supplied to the ceiling back space A, condensation in the ceiling back space A during the stop of the cooling operation of the air conditioner 21 can be suppressed.

[0051] (6) The ceiling space temperature sensor 24 measures the surface temperature of the back surface 11a of the ceiling 11 as the temperature Tas of the back surface 11a of the ceiling 11. With this configuration, the temperature Tas of the back surface 11a of the ceiling 11 can be accurately measured.

[0052] (7) The condensation prevention system 20 is installed in the ceiling space A of the top floor of the building 10. Since there are no rooms above the ceiling space A of the top floor, the temperature of the ceiling space A of the top floor tends to be higher than the temperature of the ceiling space A of the other floors during the summer. Therefore, it is particularly effective to suppress condensation in the ceiling space A of the top floor by installing the condensation prevention system 20.

[0053] (8) The operating state of the attic ventilation device 23 is automatically controlled by the control device 28. This eliminates the need for a person to manually control the operating state of the attic ventilation device 23. In winter, the air conditioning system 21 is operated in heating mode. Therefore, if the attic ventilation device 23 is operated in winter, warm air from the room R is supplied to the attic space A, which may cause condensation to occur on the steel frame structure and other components installed in the attic space A. Therefore, it is necessary to stop the attic ventilation device 23 in winter. However, if a person controls the operating state of the attic ventilation device 23, there is a risk of accidentally operating the attic ventilation device 23. In contrast, in this embodiment, the operating state of the attic ventilation device 23 is automatically controlled by the control device 28. Therefore, condensation in the attic space A caused by the operation of the attic ventilation device 23 in winter can be suppressed. Thus, according to the condensation prevention system 20 of this embodiment, not only condensation in the attic space A in summer but also condensation in the attic space A in winter can be suppressed.

[0054] (9) The air supply device 23a and the ceiling exhaust device 23b are operated simultaneously. With this configuration, the ceiling space A is less likely to become negatively pressurized, and thus the intrusion of hot and humid outside air into the ceiling space A can be suppressed.

[0055] (10) Near the indoor unit 21a, the temperature Tas near the back surface 11a of the ceiling 11 tends to drop particularly low, making it easy for condensation to occur in the space above the ceiling A. The air supply device 23a in this embodiment is located near the indoor unit 21a. As a result, indoor air R is supplied to the vicinity of the indoor unit 21a, which effectively suppresses condensation in the space above the ceiling A.

[0056] (11) The air supply device 23a in this embodiment is located away from the ceiling exhaust device 23b. This makes it easier to ventilate the entire ceiling space A. (12) The building 10 in this embodiment is a steel frame structure (S structure). In this case, the airtightness performance is often lower compared to the case of a reinforced concrete structure (RC structure) or a wooden structure, so outside air can easily enter the ceiling space A. Therefore, it is particularly effective to suppress condensation with the condensation prevention system 20 in this embodiment.

[0057] <Examples of Modifications> The above embodiment is an example of possible forms of the condensation prevention system 20 and the building 10, and is not intended to limit their forms. The condensation prevention system 20 and the building 10 may take forms different from those exemplified in the above embodiment. Examples of such forms include forms in which some of the configurations of the embodiment are replaced, modified, or omitted, or forms in which new configurations are added to the embodiment. Modifications of the embodiment are shown below.

[0058] - The condensation prevention system 20 may be installed in the ceiling space A of floors other than the top floor. - The ceiling space members may be installed in the ceiling space A of floors other than the top floor. In this case, the ceiling space members may be used as sound-absorbing materials.

[0059] - The space above the ceiling A does not necessarily need to be provided with insulating material 16 or sound-absorbing material as a ceiling space component. - In the above embodiment, the indoor unit 21a was installed on the ceiling 11, but is not limited to this. For example, the indoor unit 21a may be attached to the wall of the room R, or it may be placed on the floor of the room R.

[0060] The ceiling space temperature sensor 24 may measure the temperature Tas of a space within the ceiling space A that is approximately the same temperature as the surface temperature of the back surface 11a of the ceiling 11.

[0061] For example, if an insulating material 16 or sound-absorbing material is placed in the ceiling space A as a ceiling space component, the temperature of the space located above the back surface 11a of the ceiling 11 and below the ceiling space component will be approximately the same as the surface temperature of the back surface 11a of the ceiling 11. Therefore, the ceiling space temperature sensor 24 may measure the temperature Tas of the space located above the back surface 11a of the ceiling 11 and below the ceiling space component as the temperature Tas near the back surface 11a of the ceiling 11.

[0062] - The placement of the ceiling temperature sensor 24 may be changed as appropriate, provided that the temperature Tas near the back surface 11a of the ceiling 11 can be measured by the ceiling temperature sensor 24. For example, the ceiling temperature sensor 24 may be placed in a space above the back surface 11a of the ceiling 11 and below the ceiling space installation member in the ceiling space A.

[0063] As another example, the ceiling space temperature sensor 24 may be located outside the ceiling space A. The ceiling space temperature sensor 24 may predict the temperature Tas near the back surface 11a of the ceiling 11 from the temperature outside the ceiling space A.

[0064] Similarly, if the humidity near the back surface 11a of the ceiling 11 can be measured by the attic humidity sensor 25, the arrangement of the attic humidity sensor 25 may be changed as appropriate. In the above embodiment, the control device 28 calculated the dew point temperature Tad near the back surface 11a of the ceiling 11, but this is not limited to this. For example, the condensation prevention system 20 may include a dew point calculation device that calculates the dew point temperature Tad near the back surface 11a of the ceiling 11. The control device 28 obtains the dew point temperature Tad near the back surface 11a of the ceiling 11 from the dew point calculation device.

[0065] Similarly, in the above embodiment, the control device 28 calculated the dew point temperature Trd of the room R, but this is not limited to this. For example, the condensation prevention system 20 may include a dew point calculation device that calculates the dew point temperature Trd of the room R. The control device 28 obtains the dew point temperature Trd of the room R from the dew point calculation device.

[0066] - The control device 28 may operate the ceiling ventilation device 23 without determining whether the dew point temperature Trd of the room R is less than or equal to the dew point temperature Tad of the ceiling 11, if the temperature Tas near the back surface 11a of the ceiling 11 is less than or equal to the dew point temperature Tad of the back surface 11a of the ceiling 11. In other words, step S2 of controlling the ceiling ventilation device 23 in the above embodiment may be omitted. In this case, the condensation prevention system 20 does not need to be equipped with a room temperature sensor 26 and a room humidity sensor 27. Even in this case, at least effect (1) of the above embodiment can be obtained.

[0067] The control device 28 may be configured to receive a cooling operation start signal indicating that the air conditioning unit 21 has started cooling operation. The control device 28 may operate the ceiling space ventilation unit 23 if the temperature Tas near the back surface 11a of the ceiling 11 is less than or equal to the dew point temperature Tad near the back surface 11a of the ceiling 11 and the cooling operation start signal has been received.

[0068] - The control device 28 operated both the air supply device 23a and the ceiling space exhaust device 23b when the temperature Tas near the back surface 11a of the ceiling 11 was less than or equal to the dew point temperature Tad near the back surface 11a of the ceiling 11, but it is also possible to operate only the air supply device 23a. Even in this case, at least the effect (1) of the above embodiment can be obtained.

[0069] - The condensation prevention system 20 does not necessarily have to include an indoor ventilation device 22. - The control device 28 may operate the indoor exhaust device 22a of the indoor ventilation device 22 while the ceiling ventilation device 23 is in operation. Even in this case, at least the effect (1) of the above embodiment can be obtained.

[0070] The control device 28 may also stop the indoor exhaust device 22a of the indoor ventilation device 22 while the ceiling ventilation device 23 is stopped. Even in this case, at least the effect (1) of the above embodiment can be obtained.

[0071] The control device 28 may operate the ceiling ventilation device 23 while the air conditioning device 21 is stopped. For example, the control device 28 may operate the ceiling ventilation device 23 immediately after the cooling operation of the air conditioning device 21 has stopped. Even in this case, at least the effect (1) of the above embodiment can be obtained.

[0072] - The control device 28 may operate the indoor exhaust device 22a of the indoor ventilation device 22 while the air conditioning device 21 is stopped. - In the above embodiment, the control device 28 operated the ceiling ventilation device 23 for a predetermined time T, but is not limited to this. The control device 28 may, for example, operate the ceiling ventilation device 23 until the temperature Tas or dew point temperature Tad near the back surface 11a of the ceiling 11 reaches a predetermined temperature.

[0073] The control device 28 may operate the ceiling ventilation device 23 if the temperature Tas near the back surface 11a of the ceiling 11 is below a predetermined temperature. The predetermined temperature is set to the dew point temperature Tad + α near the back surface 11a of the ceiling 11. α is, for example, 1°C or more and 2°C or less. In this case, condensation in the ceiling space A can be suppressed more reliably.

[0074] - The building 10 is not limited to steel frame construction (S structure), but may also be reinforced concrete construction (RC structure) or wood construction. <Note> This specification discloses the following technologies.

[0075] [Note 1] A condensation prevention system comprising: an air supply device that supplies air-conditioned indoor air to the space above the ceiling; a control device that controls the air supply device; a ceiling space temperature sensor that measures the temperature near the back surface of the ceiling; and a ceiling space humidity sensor that measures the humidity near the back surface of the ceiling, wherein the control device operates the air supply device when the temperature near the back surface of the ceiling is less than or equal to the dew point temperature near the back surface of the ceiling calculated from the temperature and humidity near the back surface of the ceiling.

[0076] [Note 2] In the condensation prevention system described in Note 1, the system includes an indoor temperature sensor for measuring the temperature of the room and an indoor humidity sensor for measuring the humidity of the room, and the control device operates the air supply device when the temperature near the back surface of the ceiling is less than or equal to the dew point temperature near the back surface of the ceiling, and the indoor dew point temperature calculated from the indoor temperature and humidity is less than or equal to the dew point temperature near the back surface of the ceiling.

[0077] [Note 3] In the condensation prevention system described in Note 1, a ceiling space exhaust device is provided to discharge the air in the ceiling space to the outside, and the control device operates the ceiling space exhaust device when the temperature near the back surface of the ceiling is below the dew point temperature near the back surface of the ceiling.

[0078] [Note 4] In the condensation prevention system described in Note 3, an indoor exhaust device is provided that directly discharges the indoor air to the outside, and the control device stops the indoor exhaust device when the air supply device and the ceiling exhaust device are in operation, and operates the indoor exhaust device when the air supply device and the ceiling exhaust device are stopped.

[0079] [Note 5] In the condensation prevention system described in Note 3, the control device stops the air supply device and the ceiling exhaust device while the air conditioning device is stopped.

[0080] [Note 6] In the condensation prevention system described in Note 1, the ceiling space temperature sensor measures the surface temperature of the back surface of the ceiling as the temperature near the back surface of the ceiling.

[0081] [Note 7] In the condensation prevention system described in Note 1, the space above the ceiling is provided with an insulating material or a sound-absorbing material as a ceiling space component, and the ceiling space temperature sensor measures the temperature of the space above the back surface of the ceiling and below the ceiling space component as the temperature near the back surface of the ceiling.

[0082] [Note 8] A building equipped with a condensation prevention system as described in any one of Notes 1 to 7. [Note 9] In a building as described in Note 8, the condensation prevention system is installed in the space above the ceiling of the top floor.

[0083] 10...Building, 11...Ceiling, 11a...Back surface, 16...Insulation material as a component to be placed in the ceiling space, 20...Condensation prevention system, 21...Air conditioning system, 22a...Indoor exhaust system, 23a...Air supply system, 23b...Ceiling space exhaust system, 24...Ceiling space temperature sensor, 25...Ceiling space humidity sensor, 26...Indoor temperature sensor, 27...Indoor humidity sensor, 28...Control device, A...Ceiling space, D...Outdoors, R...Indoors.

Claims

1. A condensation prevention system comprising: an air supply device that supplies air-conditioned indoor air to the space above the ceiling; a control device that controls the air supply device; a ceiling space temperature sensor that measures the temperature near the back surface of the ceiling; and a ceiling space humidity sensor that measures the humidity near the back surface of the ceiling, wherein the control device operates the air supply device when the temperature near the back surface of the ceiling is less than or equal to the dew point temperature near the back surface of the ceiling calculated from the temperature and humidity near the back surface of the ceiling.

2. A condensation prevention system according to claim 1, comprising: an indoor temperature sensor for measuring the temperature of the room; and an indoor humidity sensor for measuring the humidity of the room, wherein the control device operates the air supply device when the temperature near the back surface of the ceiling is less than or equal to the dew point temperature near the back surface of the ceiling, and the indoor dew point temperature calculated from the indoor temperature and humidity is less than or equal to the dew point temperature near the back surface of the ceiling.

3. A condensation prevention system according to claim 1 or 2, comprising a ceiling exhaust device for discharging air from the ceiling space to the outside, wherein the control device operates the ceiling exhaust device when the temperature near the back surface of the ceiling is below the dew point temperature near the back surface of the ceiling.

4. The condensation prevention system according to claim 3, comprising an indoor exhaust device that directly discharges the indoor air to the outside, wherein the control device stops the indoor exhaust device while the air supply device and the ceiling exhaust device are in operation, and operates the indoor exhaust device while the air supply device and the ceiling exhaust device are stopped.

5. The condensation prevention system according to claim 3 or 4, wherein the control device stops the air supply device and the ceiling exhaust device when the air conditioning device is stopped.

6. The condensation prevention system according to any one of claims 1 to 5, wherein the ceiling space temperature sensor measures the surface temperature of the back surface of the ceiling as the temperature near the back surface of the ceiling.

7. The condensation prevention system according to any one of claims 1 to 5, wherein the space above the ceiling is provided with insulating material or sound-absorbing material as a member to be placed above the ceiling, and the space above the ceiling temperature sensor measures the temperature of the space above the back surface of the ceiling and below the member to be placed above the ceiling as the temperature near the back surface of the ceiling.

8. A building equipped with a condensation prevention system according to any one of claims 1 to 7.

9. The building according to claim 8, wherein the condensation prevention system is installed in the ceiling space of the top floor.

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