Condensation prevention system and building

Abstract

To provide a condensation prevention system and building that can suppress condensation in the space above the ceiling. [Solution] The condensation prevention system comprises an air supply device, a control device, a ceiling space temperature sensor, and a ceiling space humidity sensor. The air supply device supplies conditioned indoor air from the air conditioning system to the ceiling space. The control device controls the air supply device. The ceiling space temperature sensor measures the temperature Tas near the underside of the ceiling. The ceiling space humidity sensor measures the humidity near the underside of the ceiling. The control device operates the air supply device if the temperature Tas near the underside of the ceiling is less than or equal to the dew point temperature Tad near the underside of the ceiling, which is calculated from the temperature Tas and humidity near the underside of the ceiling.

Description

Technical Field

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

Background Art

[0002] Suppression of dew condensation in the ceiling space of a building is desired. For example, Patent Document 1 discloses a ventilation device that suppresses dew condensation on the surface of a duct disposed in the ceiling space.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In summer, hot and humid outside air invades 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 invaded the ceiling space is cooled by the ceiling, there is a risk of dew condensation in the ceiling space.

Means for Solving the Problems

[0005] (1) The dew condensation prevention system for solving the above problems includes an air supply device that supplies indoor air 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] In this configuration, when the temperature near the underside of the ceiling is below the dew point temperature near the underside of the ceiling, that is, when condensation can occur in the space above the ceiling, the cooler indoor air conditioned by the cooling operation of the air conditioner is supplied to the space above the ceiling by the air supply device. This reduces the temperature difference between the space above the ceiling and the room, thereby suppressing condensation in the space above the ceiling.

[0007] (2) The condensation prevention system described in (1) above 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. With this configuration, indoor air with a dew point temperature below the dew point temperature near the underside of the ceiling is supplied to the space above the ceiling, thus further suppressing condensation in the space above the ceiling.

[0008] (3) In the condensation prevention system of (1) or (2) above, 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. 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.

[0009] (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. With this configuration, the air supply system, the ceiling exhaust system, and the indoor exhaust system are not operated simultaneously, thus reducing energy loss.

[0010] (5) In the condensation prevention system described in (3) or (4) above, the control device stops the air supply device and the ceiling exhaust device while the air conditioning device is stopped. 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.

[0011] (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. This configuration allows for accurate measurement of the temperature near the back of the ceiling.

[0012] (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.

[0013] (8) A building that solves the above problems is equipped with one of the condensation prevention systems described in (1) to (7) above. In this configuration, when the temperature near the underside of the ceiling is below the dew point temperature near the underside of the ceiling, that is, when condensation can occur in the space above the ceiling, the cooler indoor air conditioned by the cooling operation of the air conditioner is supplied to the space above the ceiling by the air supply device. This reduces the temperature difference between the space above the ceiling and the room, thereby suppressing condensation in the space above the ceiling.

[0014] (9) In the building described in (8) above, the condensation prevention system is installed in the space above the ceiling on the top floor. According to this configuration, in summer, the temperature of the ceiling space on the top floor is likely to be higher than the temperature of the ceiling spaces on the other floors. Therefore, in the ceiling space on the top floor, it is particularly effective to suppress condensation in the ceiling space by providing a condensation prevention system.

Advantages of the Invention

[0015] According to the condensation prevention system and the building of the present disclosure, condensation in the ceiling space can be suppressed.

Brief Description of the Drawings

[0016] [Figure 1] It is a schematic diagram of the condensation prevention system. [Figure 2] It is an enlarged view of the condensation prevention system. [Figure 3] It is a configuration diagram of the condensation prevention system. [Figure 4] It is a flowchart showing the control of the ceiling ventilation device executed by the control device. [Figure 5] It is a timing chart showing changes in the dew point temperature near the back surface of the ceiling, the operating state of the ceiling ventilation device, the operating state of the indoor ventilation device, and the operating state of the air conditioning device.

Embodiments for Carrying Out the Invention

[0017] Referring to FIGS. 1 to 5, the condensation prevention system 20 and the building 10 of the present embodiment will be described. The building 10 is, for example, a single-family house, a multi-family house, a lodging facility, an office, a building, or the like. The building 10 of the present embodiment is a steel frame structure (S structure).

[0018] As shown in FIG. 1, the building 10 includes a condensation prevention system 20. The condensation prevention system 20 of the present embodiment is provided in the ceiling space A on the top floor. The ceiling space A on the top floor is a space surrounded by the ceiling 11, the roof 12, and the outer wall 13 on the top floor. Outside air enters the ceiling space A through the gaps in the outer wall 13. In summer, the outside air that enters the ceiling space A is hot and humid.

[0019] As shown in FIGS. 1 and 2, the ceiling 11 has a plurality of battens 14 and a ceiling material 15. The plurality of battens 14 are arranged side by side at intervals. The ceiling material 15 is composed of a gypsum board. The ceiling material 15 is fixed to the lower surfaces of the plurality of battens 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 on the opposite side to the indoor R side surface of the ceiling 11.

[0020] On the plurality of battens 14, a heat insulating material 16 as a ceiling back arrangement member is placed. Therefore, in the ceiling back space A, a heat insulating material 16 as a ceiling back arrangement member is provided. The heat insulating material 16 of the present embodiment is composed of glass wool or rock wool. The heat insulating material 16 is provided so as to partition the ceiling back space A vertically. Although not shown, the portion of the heat insulating material 16 not supported by the battens 14 may bend downward.

[0021] <Dew condensation prevention system> As shown in FIGS. 1 and 3, the dew condensation prevention system 20 includes an air conditioner 21, an indoor ventilation device 22, and a ceiling back ventilation device 23.

[0022] The air conditioner 21 performs air conditioning of the indoor R based on a command from the user. The air conditioner 21 has an indoor unit 21a. The indoor unit 21a of the present embodiment is provided on the ceiling 11. The air conditioner 21 is configured to be able to perform a cooling operation. By the cooling operation of the air conditioner 21, the temperature of the indoor R decreases.

[0023] 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.

[0024] The ceiling ventilation device 23 ventilates the ceiling space A. The ceiling ventilation device 23 includes an air supply device 23a and a ceiling exhaust device 23b. The air supply device 23a supplies air from room R to the space above the ceiling A. As described above, room R is air-conditioned by the air conditioning unit 21. Therefore, the air supply device 23a can supply air from room R, which has been air-conditioned by the air conditioning unit 21, to the space above the ceiling A. The air supply device 23a consists 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 space above the ceiling exhaust device 23b, more specifically, on the opposite side of the indoor unit 21a from the space above the ceiling exhaust device 23b. When the air supply device 23a is operated, air from room R is supplied to the space above the insulation material 16 in the space above the ceiling A.

[0025] 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 air exhausted 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.

[0026] 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.

[0027] The attic temperature sensor 24 and attic humidity sensor 25 in this embodiment are attached to the back surface 11a of the ceiling 11. The attic temperature sensor 24 and 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. The attic temperature sensor 24 in this embodiment 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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 unit 21 has stopped.

[0032] <Control of the ceiling ventilation system> The control of the ceiling ventilation system 23, performed by the control device 28, will be described below. 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.

[0033] 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 ventilation device 23 (step S3). In this embodiment, the control device 28 operates both the supply air device 23a and the ceiling 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.

[0034] <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.

[0035] In this embodiment, the control device 28 stops the indoor exhaust device 22a of the indoor ventilation system 22 at the same time as the operation of the attic ventilation system 23 starts. Therefore, the indoor ventilation system 22 is stopped while the attic ventilation system 23 is operating. Also, the control device 28 starts the indoor exhaust device 22a of the indoor ventilation system 22 at the same time as the operation of the attic ventilation system 23 stops. Therefore, the indoor exhaust device 22a operates while the attic ventilation system 23 is stopped.

[0036] 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.

[0037] 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.

[0038] [Operation of this embodiment] The operation of this embodiment will now be explained. The condensation prevention system 20 includes a ceiling ventilation device 23, a control device 28, a ceiling temperature sensor 24, and a ceiling humidity sensor 25. The ceiling ventilation device 23 has an air supply device 23a and a ceiling 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 exhaust device 23b discharges the air from the ceiling space A to the outdoors D. The control device 28 controls the ceiling ventilation device 23. 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. The control device 28 operates the ceiling ventilation device 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, 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.

[0039] The air supply device 23a supplies cool indoor air R, conditioned by the cooling operation of the air conditioning unit 21, to the space above the ceiling A. The exhaust device 23b exhausts the hot, humid air that has entered the space above the ceiling A to the outside D. Because the space above the ceiling A is ventilated by the space above the ceiling ventilation device 23, the temperature difference between the space above the ceiling A and the indoor R is reduced, thereby suppressing condensation in the space above the ceiling A.

[0040] [Effects of this embodiment] The effects of this embodiment will now be explained. (1) The condensation prevention system 20 includes an air supply device 23a, a control device 28, a ceiling space temperature sensor 24, and a ceiling space humidity sensor 25. 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 control device 28 controls the air supply device 23a. 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 air supply device 23a 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, which is calculated from the temperature Tas and humidity near the back surface 11a of the ceiling 11.

[0041] With this configuration, in situations where condensation may occur in the space above the ceiling A, the cooler indoor air R, conditioned by the cooling operation of the air conditioning unit 21, is supplied to the space above the ceiling A by the air supply unit 23a. This reduces the temperature difference between the space above the ceiling A and the indoor R, thereby suppressing condensation in the space above the ceiling A.

[0042] (2) The condensation prevention system 20 is equipped with an indoor temperature sensor 26 and an indoor humidity sensor 27. The indoor temperature sensor 26 measures the temperature of the indoor R. The indoor humidity sensor 27 measures the humidity of the indoor R. The control device 28 operates the air supply device 23a 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, and the dew point temperature Trd of the indoor R, calculated from the temperature and humidity of the indoor R, is less than or equal to the dew point temperature Tad near the back surface 11a of the ceiling 11.

[0043] With this configuration, indoor air R with a dew point temperature Trd below the dew point temperature Tad near the back surface 11a of the ceiling 11 is supplied to the space above the ceiling A, thus further suppressing condensation in the space above the ceiling A.

[0044] (3) The condensation prevention system 20 is equipped with a ceiling exhaust device 23b. The ceiling exhaust device 23b discharges the air from the ceiling space A to the outside D. The control device 28 operates the ceiling exhaust device 23b 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.

[0045] With this configuration, if condensation may occur in the attic space A, the air in the attic space A is discharged to the outside D by the attic exhaust device 23b. By ventilating the attic space A with the air supply device 23a and the attic exhaust device 23b, condensation in the attic space A can be further suppressed.

[0046] (4) The condensation prevention system 20 is equipped with an indoor exhaust device 22a. The indoor exhaust device 22a directly discharges indoor air R to the outdoors D. The control device 28 stops the indoor exhaust device 22a when the supply air device 23a and the ceiling exhaust device 23b are in operation. The indoor exhaust device 22a is operated when the supply air device 23a and the ceiling exhaust device 23b are stopped.

[0047] With this configuration, the air supply unit 23a and the ceiling exhaust unit 23b and the indoor exhaust unit 22a are not operated simultaneously, thus reducing energy loss. (5) The control device 28 stops the supply air device 23a and the ceiling exhaust device 23b when the air conditioning device 21 is stopped.

[0048] With this configuration, when the air conditioning unit 21 is stopped, the air supply unit 23a and the ceiling exhaust unit 23b are also stopped, thus reducing energy loss. In addition, in the summer, the air conditioning unit 21 does not supply unconditioned, hot and humid indoor air R to the ceiling space A, thus suppressing condensation in the ceiling space A when the air conditioning unit 21 is stopped from cooling.

[0049] (6) The ceiling space 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. With this configuration, the temperature Tas near the back surface 11a of the ceiling 11 can be accurately measured.

[0050] (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.

[0051] (8) The operating status of the ceiling ventilation device 23 is automatically controlled by the control device 28. This eliminates the need for a person to manually control the operating status of the ceiling ventilation device 23. In winter, the air conditioning system 21 operates in heating mode. Therefore, if the attic ventilation system 23 is operated in winter, warm air from the room R is supplied to the attic space A, which may cause condensation on the steel frame and other structures installed in the attic space A. Consequently, it is necessary to stop the attic ventilation system 23 in winter. However, if a person controls the operating state of the attic ventilation system 23, there is a risk of accidentally operating the attic ventilation system 23. In contrast, in this embodiment, the operating state of the attic ventilation system 23 is automatically controlled by the control device 28. Therefore, condensation in the attic space A caused by the operation of the attic ventilation system 23 in winter can be suppressed. Consequently, the condensation prevention system 20 of this embodiment can suppress not only condensation in the attic space A in summer, but also condensation in the attic space A in winter.

[0052] (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.

[0053] (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.

[0054] (11) In this embodiment, the air supply device 23a 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 made of steel frame (S structure). In this case, the airtightness performance is often lower compared to the case of a reinforced concrete (RC structure) or wooden structure, so outside air can easily enter the space above the ceiling A. Therefore, it is particularly effective to suppress condensation with the condensation prevention system 20 of this embodiment. <Example of changes> The above embodiments are illustrative of possible forms of the condensation prevention system 20 and the building 10, and are not intended to limit their forms. The condensation prevention system 20 and the building 10 may take forms different from those illustrated in the above embodiments. Examples include forms in which some of the configurations of the embodiments are replaced, modified, or omitted, or forms in which new configurations are added to the embodiments. Modifications of the embodiments are shown below.

[0055] 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.

[0056] • The space above the ceiling A does not necessarily need to be equipped with insulating material 16 or sound-absorbing material as a component to be placed above the ceiling. In the above embodiment, the indoor unit 21a was installed on the ceiling 11, but it is not limited to this. For example, the indoor unit 21a may be mounted on the wall of the room R, or it may be placed on the floor of the room R.

[0057] The ceiling space temperature sensor 24 may measure the temperature Tas of the 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.

[0058] For example, if an insulating material 16 or a 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.

[0059] 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 space temperature sensor 24 may be located in a space above the back surface 11a of the ceiling 11 and below the ceiling space installation member in the ceiling space A.

[0060] 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.

[0061] Similarly, if the humidity near the back surface 11a of the ceiling 11 can be measured by the ceiling humidity sensor 25, the placement of the ceiling 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 it 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.

[0062] 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.

[0063] 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 room R, 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.

[0064] 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.

[0065] The control device 28 previously 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.

[0066] The condensation prevention system 20 does not need to be equipped with 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. In this case as well, at least the effect (1) of the above embodiment can be obtained.

[0067] 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.

[0068] 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.

[0069] 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. 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, between 1°C and 2°C. In this case, condensation in the ceiling space A can be suppressed more reliably. Building 10 is not limited to steel frame construction (S structure), but may also be reinforced concrete construction (RC structure) or wood construction.

[0070] <Note> This specification discloses the following technologies: [Note 1] A condensation prevention system comprising: an air supply device that supplies 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.

[0071] [Note 2] The condensation prevention system described in Appendix 1 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.

[0072] [Note 3] In the condensation prevention system described in Appendix 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.

[0073] [Note 4] In the condensation prevention system described in Appendix 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.

[0074] [Note 5] In the condensation prevention system described in Appendix 3, the control device stops the air supply device and the ceiling exhaust device while the air conditioning device is stopped.

[0075] [Note 6] In the condensation prevention system described in Appendix 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.

[0076] [Note 7] In the condensation prevention system described in Appendix 1, the space above the ceiling is provided with insulating material or 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.

[0077] [Note 8] A building equipped with a condensation prevention system as described in any one of the appendices 1 to 7. [Note 9] In the building described in Appendix 8, the condensation prevention system is installed in the space above the ceiling on the top floor. [Explanation of Symbols]

[0078] 10...Building, 11...Ceiling, 11a...Back surface, 16...Insulation material as a component 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. An air supply device that supplies conditioned indoor air from an air conditioning system to the space above the ceiling, A control device for controlling the aforementioned air supply device, A ceiling temperature sensor that measures the temperature near the back of the ceiling, A ceiling humidity sensor that measures the humidity near the back surface of the ceiling, Equipped with, The control device is a condensation prevention system that 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, which is calculated from the temperature and humidity near the back surface of the ceiling.

2. An indoor temperature sensor for measuring the temperature of the room, An indoor humidity sensor for measuring the humidity in the room, Equipped with, The condensation prevention system according to claim 1, wherein 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 room temperature and humidity is below the dew point temperature near the back surface of the ceiling.

3. The system includes an attic exhaust device that discharges the air in the attic space to the outside. The condensation prevention system according to claim 1, wherein 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.

4. The system includes an indoor exhaust device that directly discharges the indoor air to the outside, The control device is While the aforementioned air supply device and the aforementioned ceiling exhaust device are in operation, the aforementioned indoor exhaust device shall be stopped. The condensation prevention system according to claim 3, wherein the indoor exhaust system is operated while the air supply system and the ceiling exhaust system are stopped.

5. The condensation prevention system according to claim 3, 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 claim 1, 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. In the aforementioned space above the ceiling, insulating material or sound-absorbing material is provided as a component to be placed above the ceiling. The condensation prevention system according to claim 1, wherein the ceiling space temperature sensor measures the temperature of the space above the back surface of the ceiling and below the ceiling space member 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 space above the ceiling on the top floor.

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