JP3506333B2 - Ceiling heat recovery machine - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an in-ceiling heat recovery machine.

[0002]

2. Description of the Related Art When supplying outside air indoors in a building air conditioner or the like, an air conditioner dedicated to outside air processing or combined with outside air processing is used.

[0003]

However, during heating operation in extremely cold regions, if the outside air below the freezing point, which has a very large temperature difference from the indoor air, is directly introduced into the air conditioner for heat exchange, the efficiency will be poor and the capacity will be extremely high. A large heat exchanger is required, and the overall size becomes large and a large installation space is required, resulting in high cost. Then, it aims at providing the heat recovery machine in a ceiling which solves these problems.

[0004]

In order to achieve the above-mentioned object, the in-ceiling heat recovery machine of the present invention has an in-ceiling air inlet, an in-ceiling air outlet, an outside air inlet and an outside air outlet formed in the machine body. A heat recovery air passage communicating with the air inlet inside the ceiling and an air outlet inside the ceiling and an outside air processing air passage communicating with the outside air inlet and the outside air outlet are formed inside, and the outside air from the outside air inlet and the inside air ceiling A sensible heat exchanger or total heat exchanger for exchanging heat with the ceiling air is installed over the heat recovery air passage and the outside air treatment air passage so that the heat recovery outside air from the outside air outlet is taken into the air conditioner. It is composed. Further, the sensible heat exchanger includes a rectangular tubular frame through which air passes, and a heat transfer tube group that is inserted so as to penetrate a pair of opposing surfaces of the rectangular tubular frame and through which air passes through. It was Further, the in-ceiling air inlet and the in-ceiling air outlet are arranged close to one side of the machine body, and the outside air outlet and the outside air inlet are arranged close to the other side of the machine body. Furthermore, the outside air outlet of the airframe is connected to the outside air intake of the ceiling-mounted air-cooling heat pump type air conditioner directly or via a duct, and the air supply port and the exhaust are connected to one of the opposite end faces of the casing of this air cooling heat pump type air conditioner. An intake air is formed and an outside air intake and an exhaust port are formed on the other of the facing end faces, and an exhaust air blow passage having a condenser and a blower in communication with the exhaust air intake and the exhaust port is formed in the casing. Outside air ventilation passage communicating with the windward side of the condenser in the exhaust ventilation passage, air supply ventilation passage with one end communicating with the air supply port and having an evaporator and a blower, exhaust air from the exhaust ventilation passage and outside air of the outside air ventilation passage And a damper mechanism capable of adjusting the air volume of each of the outside air of the air supply air passage, and the air supply air passage and the exhaust air supply passage are sandwiched by the air supply air supply passage and the exhaust air supply air passage in parallel, and the other end of the outside air air supply passage is supplied with air. Connect the outside air intake to the other end of the air passage. It was. Further, the outside air outlet of the airframe is connected to the outside air inlet of the floor-standing air-cooled heat pump type air conditioner directly or through a duct, and the air supply port and the exhaust inlet are connected to one end surface of the casing of this air cooled heat pump type air conditioner. An outside air intake and an exhaust port are formed, and an exhaust air blow passage in which the exhaust air intake and the exhaust port are connected to each other and a condenser and a blower are provided in the casing, and an evaporator and a blower are connected to the outside air intake and the air supply port. With the air supply air duct provided,
Adjust the air volume of the outside air ventilation passage that communicates with the windward of the condenser of the exhaust air ventilation passage and the windward of the evaporator of the air supply ventilation passage, and the outside air of the exhaust air of the exhaust air ventilation passage and the outside air ventilation passage and the outside of the air supply ventilation passage. A flexible damper mechanism is provided, and the air supply air supply passage and the exhaust air supply air passage are formed so as to make a U-turn, and are arranged in parallel.

[0005]

1 to 5 show an embodiment of a heat recovery system in a ceiling according to the present invention. This heat recovery system in a ceiling includes a body 21, an air inlet 22 in the ceiling and a ceiling. The inside air outlet 23, the outside air inlet 24, and the outside air outlet 25 are formed, and
A heat recovery air passage E that communicates with the in-ceiling air inlet 22 and the in-ceiling air outlet 23 and an outside air treatment air passage F that communicates with the outside air inlet 24 and the outside air outlet 25 are formed inside. A sensible heat exchanger 26 for exchanging heat between the outside air and the air inside the ceiling from the air inlet 22 is provided over the heat recovery air passage E and the outside air processing air passage F, and the heat recovery outside air from the outside air outlet 25 is air-conditioned. It is configured to be taken into the machine 27. Further, a bypass air passage G communicating with the outside air inlet 24 and the outside air outlet 25 is formed inside the machine body 21 (that is, the outside air treatment air passage F).
And the bypass air passage G form a branch passage having the outside air inlet 24 and the outside air outlet 25 as a common inlet / outlet), an outside air damper 31 is provided in the outside air treatment air passage F, and the bypass damper 3 is provided in the bypass air passage G.
2 is provided so that the outside air flow can be switched to only one of the outside air processing air passage F and the bypass air passage G. The air flow is
1 to 3 and FIG. 14 only are indicated by thick solid line arrows and dotted arrows, and in the other figures, they are indicated by solid and dotted outline arrows.

[0006] The sensible heat exchanger 26 is inserted and attached so as to penetrate a square tubular frame 28 through which one of the air inside the ceiling and the outside air passes, and a pair of opposing surfaces of the square tubular frame 28. Heat transfer tube group 29 through which the other of the air in the ceiling and the outside air passes through
And the inside air and the outside air are heat-exchanged via the heat transfer tube group 29. The heat transfer tube group 29 includes a large number of heat transfer tubes 3
0s are arranged in parallel with each other with a predetermined gap. If the outside air is allowed to pass through the heat transfer tube 30, moisture condenses on the outer peripheral surface of the heat transfer tube 30 during the heating operation, so that even if it freezes, failure such as rupture does not occur. Although the heat transfer tube 30 may be a circular tube, it is preferably an elliptical tube, and the elliptical major axis thereof is substantially parallel to the ventilation direction. Although not shown, a total heat exchanger may be used in place of the sensible heat exchanger 26.

An air inlet 22 in the ceiling is provided on one side of the airframe 21.
And the air outlet 23 in the ceiling are arranged close to each other, and the outside air outlet 25 and the outside air inlet 24 are arranged close to each other on the other side of the machine body 21.
In the illustrated example, the air inlet 2 in the ceiling is provided on one of the opposite end surfaces of the machine body 21.
2 and the outside air outlet 25 are provided, and the in-ceiling air outlet 23 and the outside air inlet 24 are provided on the other of the opposite end surfaces so that the heat recovery air passage E and the outside air treatment air passage F intersect twice in the machine body 21. The in-ceiling air inlet 22 and the in-ceiling air outlet 23 are arranged so that the outside air outlet 25 and the outside air inlet 24 face each other in front.

The outside air outlet 25 of the machine body 21 is connected to the outside air intake 6 of a ceiling-mounted air-cooling heat pump type air conditioner 27 directly or through a duct. The outside air inlet 24 of the machine body 21 communicates with the outside through a duct, and the in-ceiling air inlet 22 and the in-ceiling air outlet 23 communicate with the inside of the ceiling either directly or through a duct. During the heating operation, the outside air damper 31 is opened and the bypass damper 32 is closed, and the blower 3 of the air conditioner 27 takes in low temperature outside air into the airframe 21 at the same time.
At 3, the air in the ceiling, which is hotter than the outside air, is taken into the body 21. The outside air and the air in the ceiling are sensible heat-exchanged by the sensible heat exchanger 26, and the outside air is heated (preheated) by the heat of the air in the ceiling. This preheated outside air is taken into the air conditioner 27. The heat-recovered air in the ceiling is returned to the ceiling. During cooling operation,
It is also possible to open the bypass damper 32 and close the outside air damper 31, and send the outside air as it is to the air conditioner 27.

As shown in FIGS. 6 to 8, a ceiling-mounted air-cooled heat pump type air conditioner 27 has an air supply port 7 and an exhaust gas intake port 8 formed on one of a pair of opposed end faces of a casing 1 and the opposed faces. The outside air intake 6 and the exhaust port 10 are formed on the other end face,
In the casing 1, an exhaust air blow passage B in which a condenser 4 also serving as an exhaust heat recovery and a blower 5 is provided in communication with the exhaust air intake 8 and the exhaust air outlet 10, and the windward side of the condenser 4 having an exhaust air blow passage B at one end. To the outside air blow passage C, one end of which is connected to the air supply port 7 and which is provided with the evaporator 2 and the blower 3, and the exhaust air blow passage B is exhausted and the outside air blow passage C is supplied to the outside air. A damper mechanism D capable of adjusting the amount of each of the outside air in the air blowing passage A, a compressor 12, a liquid receiver,
A refrigerating circuit 11 including an expansion valve, a switching valve, and the like, capable of switching between heat absorption and heat radiation, is provided, and the outside air blow passage C is sandwiched between the supply air blow passage A and the exhaust blow passage B in parallel, and the outside air blow passage C is also provided. The outside air intake 6 is communicated with the other end of the air supply air duct A and the refrigeration circuit 11 having the condenser 4, the evaporator 2 and the compressor 12 is taken out from the casing 1. It can be stored freely.

Specifically, a refrigeration circuit 11 having a condenser 4, an evaporator 2 and a compressor 12 is fixed and integrated to a frame 15 which is detachably mounted in the casing 1, and an opening is formed on one surface of the casing 1. Forming part 16 and opening 1
The refrigerating circuit-equipped frame 15 can be taken out and stored with respect to No. 6. The opening 16 is provided with a detachable or openable / closable exterior plate 17, and a drain pan (not shown) is detachably attached to the frame with a refrigeration circuit 15. Although the opening 16 is the bottom surface of the casing 1 in the illustrated example, it may be formed on a surface other than the bottom surface such as a side surface.

In the casing 1, an exhaust damper 13 for adjusting the amount of exhaust air from the exhaust intake 8 to the condenser 4, and an amount of outside air from the outside air intake 6 to the condenser 4 are sent to the condenser 4. The outside air damper 14 that assists the air volume and the air supply damper 9 that adjusts the outside air volume from the outside air intake 6 to the evaporator 2 are provided to configure the damper mechanism D. Each damper 13, 14,
9 is configured so that the air volume can be adjusted between 0 and 100%.
The exhaust air intake port 8 is communicatively connected to a room or the like via a duct or a suction port, and the air supply port 7 is communicatively connected to a room or the like via a duct or a blowout port. When installing this air conditioner on the ceiling of an indoor corridor, etc., the outside air intake 6 and the exhaust port 10 are connected to the outside through a duct or the like, but depending on the installation location such as a veranda, the duct may be omitted. Is.

The evaporator 2 is divided into a windward side divided evaporator 2a and a leeward side divided evaporator 2b at a distance, and a condenser 4 shared by the windward side divided evaporator 2a, the first compressor 12 and the first side is provided. One refrigeration circuit 11 is configured. The capacity ratio of the compressors 12 and 12 (one of the divided evaporators: the other of the divided evaporators) of the two refrigeration circuits 11 and 11 is optimally set to 4: 6, but other ratios may be used. Usually, when cooling (cooling) and heating (heating) are switched and used in the same evaporator, the capacity required for heating is about 60% of that for cooling. Therefore, by setting the division ratio as described above, energy saving can be achieved by using only the windward side division evaporator 2a, that is, only the compressor 12 of the one refrigeration circuit 11 at the time of heating. The surface wind speed of the evaporator 2 is set to 3.5 to 4.0 m / s, and the small wind condenser 4 can be used at high wind speed, and the air conditioner can be made compact, so the surface wind speed of the condenser 4 is 4.0 to 6. The optimum setting is 0.0 m / s, but a range other than these may be set. The fin tubes 19 of the evaporator 2 and the condenser 4 are preferably elliptical tubes (see FIG. 9), but may be circular tubes.

In the air-cooling heat pump type air conditioner 27, the outside air taken in from the outside air intake 6 is heat-exchanged by the evaporator 2, and the humidifier is operated to supply air from the air supply port 7 at the same time. The circulating refrigerant in the condenser 4 is heat-exchanged with the exhaust gas (return air) taken in from the exhaust gas intake port 8 to absorb or radiate heat, and is exhausted to the outside from the exhaust gas port 10. In this way, the heat exchange load of the condenser 4 can be reduced by utilizing the exhaust heat. At this time, when the air volume is insufficient with only the exhaust gas, the outside air damper 14 makes the outside air flow to the condenser 4 to supplement the air volume. That is,
Even if the amount of air required for heat exchange in the condenser 4 becomes insufficient, the amount of air can be easily increased by the outside air damper 14, and various air conditioning conditions can be widely supported.

Further, depending on the temperature (heat load) of the outside air before heat exchange in the air-cooled heat pump type air conditioner 27, only one or both of the two divided evaporators 2a and 2b (refrigerating circuits 11 and 11) are provided. The indoor air supply temperature can be easily adjusted by appropriately switching the operation mode. Moreover, the split evaporator 2
Even when only one of a and 2b (refrigerating circuits 11 and 11) is operated, since the condenser 4 shares the two refrigerating circuits 11 and 11 in one fin group, the heat transfer area is increased and the heat exchange capacity is increased. Higher than the net evaporator split ratio. It should be noted that the compressors 12 and 12 may be stopped in the outside air cooling operation and the ventilation operation.

Further, the air-cooling heat pump type air conditioner 27 can perform dehumidification / reheat operation, cool the outside air by the circulating refrigerant of the windward side split evaporator 2a to dehumidify it, and then dehumidify the dehumidified air on the leeward side. The circulating refrigerant in the condenser 2b is heated to supply air indoors from the air supply port 7, the exhaust refrigerant exchanges heat with the circulating refrigerant in the condenser 4 and is exhausted from the exhaust port 10. At this time, the condenser 4
Since the fin group is shared by the two refrigeration circuits 11, 11, not only the heat exchange between the refrigerant and the outside air, but also the refrigerants having a larger temperature difference (heating refrigerant temperature-cooling refrigerant temperature)
Heat exchange can also be performed, and the heat exchange capacity is enhanced.

In the above-mentioned embodiment, an example of connection between the in-ceiling heat recovery machine and the ceiling-mounted air-cooling heat pump type air conditioner 27 is shown, but as shown in FIGS. 10 to 14, it is connected to the floor-standing air-cooling heat pump type air conditioner 27. You can also do it. The air conditioner 27 has an air supply port 7, an exhaust gas intake port 8, an outside air intake port 6 and an exhaust gas port 10 formed on one end surface of the casing 1 and communicates with the exhaust gas intake port 8 and the exhaust gas port 10 inside the casing 1. An exhaust air blow passage B provided with a condenser 4 also serving as an exhaust heat recovery and a blower 5, an air feed air blow passage A provided with an evaporator 2 and a blower 3 in communication with an outside air intake 6 and an air intake 7, and an exhaust air blow Upwind of the condenser 4 on the path B and the air supply air path A
The outside air blowing path C communicating with the windward side of the evaporator 2, the damper mechanism D capable of adjusting the air volume of the exhaust air of the exhaust blowing path B, the outside air of the outside air blowing path C, and the outside air of the supply air blowing path A, respectively, and the compressor. 12, a refrigeration circuit 11 including a liquid receiver, an expansion valve, a switching valve, and the like, capable of switching between heat absorption and heat radiation, and the air supply air passage A and the air exhaust air passage B are formed so as to make U turns and are parallel to each other. Adjacent to
Refrigeration circuit 11 having condenser 4, evaporator 2 and compressor 12
Is configured to be freely taken out and stored in the casing 1.

Specifically, a refrigeration circuit 11 having a condenser 4, an evaporator 2 and a compressor 12 is fixed and integrated to a frame 15 which is detachably mounted in the casing 1, and an opening is formed on one surface of the casing 1. Forming part 16 and opening 1
The refrigerating circuit-equipped frame 15 can be taken out and stored with respect to No. 6. The opening 16 is provided with a detachable or openable / closable exterior plate 17, and a drain pan (not shown) is detachably attached to the frame with a refrigeration circuit 15. Although the opening 16 is on the front surface of the casing 1 in the illustrated example, it may be formed on a surface other than the front surface such as a side surface. The other structure is the same as that of the above-mentioned ceiling-mounted air-cooled heat pump type air conditioner 27, and the description thereof will be omitted.

Although not shown in the drawings, the air-cooling heat pump type air conditioner 27 may be configured by using one evaporator 2 without dividing the evaporator 2 and one refrigerating circuit 11 in each of the above embodiments.

[0019]

According to the first and second aspects of the present invention, the heat of the air accumulated in the ceiling is not wasted and can be effectively utilized and the outside air can be preheated and sent to the air conditioner. Efficiency is improved even during heating operation in the ground, energy saving, air conditioner size reduction and cost reduction can be achieved. According to the invention of claim 1,
The heat can be exchanged because the condenser can be operated using the exhaust heat from indoors.
It has a high exchange capacity and can miniaturize the refrigeration circuit to save energy and
The whole controller can be made compact and the installation space is small.
End, reduce equipment cost and running cost
It From the indoor side to one of the opposite end faces of the air conditioner casing
You can connect the duct from the outside to the other
This makes duct construction even easier and is ideal for ceiling installation.
It The outside air duct of the air conditioner is sandwiched between the air supply duct and the exhaust air duct.
Therefore, the evaporation of the supply air duct and the exhaust air duct
The outside air flow path is an obstacle when
The work is easy and the casing is flat and thin
It is compact and ideal for ceiling installation. Claim 2
In the invention, the condenser can be operated by utilizing the exhaust heat from the inside.
Since the heat exchange capacity is high, the refrigeration circuit can be downsized, which saves energy.
The entire air conditioner can be made compact and the installation space can be reduced.
Less cost, equipment cost and running cost
Can be reduced. All empty spaces on one end of the air conditioner casing
Since the air inlet and outlet are provided, duct construction is easy. Sky
The air supply duct of the air conditioner is formed to make a U-turn.
Therefore, even if the air conditioner is not made bulky, it is possible to take a long blast distance and make noise.
Large attenuation of sound energy results in low noise, even in the vicinity of the room
Easy to install. According to the third aspect of the invention, since heat is exchanged via the individual heat transfer tubes, it is difficult to freeze even in cold regions where the outside air temperature is extremely low during heating operation, and a stable heat recovery capability can be exerted at all times. According to the invention of claim 4 , when the heat recovery device in the ceiling and the air conditioner are connected by a duct, they can be connected in a straight line without intersecting, the construction of the duct becomes easy, and it is not necessary to unnecessarily lengthen the duct, thereby reducing the cost. Becomes

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment of the present invention.

FIG. 2 is a side view of FIG.

FIG. 3 is a simplified perspective view with a part omitted.

FIG. 4 is a perspective view of a sensible heat exchanger.

FIG. 5 is a plan view showing a connection example with a ceiling-mounted air-cooled heat pump air conditioner.

FIG. 6 is a plan view of a ceiling-mounted air-cooled heat pump type air conditioner.

FIG. 7 is a side view of FIG.

FIG. 8 is a simplified explanatory diagram of a refrigeration circuit.

FIG. 9 is a cross-sectional view of a fin tube group.

FIG. 10 is a plan view showing a connection example with a floor-standing air-cooling heat pump type air conditioner.

FIG. 11 is a front view showing a floor-standing air-cooled heat pump type air conditioner.

FIG. 12 is a side view of FIG. 11.

13 is a plan view of FIG. 11. FIG.

FIG. 14 is a simplified explanatory diagram of each air duct.

[Explanation of symbols]

1 casing 2 evaporator 3 blower 4 condenser 5 blower 6 Outside air intake 7 Air supply port 8 Exhaust intake 10 exhaust port 11 Refrigeration circuit 12 compressor 19 fin tubes 21 Aircraft 22 Air inlet in the ceiling 23 Air outlet in ceiling 24 Outside air inlet 25 Outside air outlet 26 Sensible heat exchanger 27 air conditioner 28 Square tubular frame 29 Heat transfer tube group A air supply air duct B Exhaust air duct C Outside air duct D damper mechanism E Heat recovery air duct F Outside air treatment air passage

─────────────────────────────────────────────────── --Continued from the front page (56) References JP 10-332181 (JP, A) JP 59-183293 (JP, A) JP 53-54341 (JP, A) Actual 60- 135557 (JP, U) Actual development 4-103540 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) F24F ^7/ 08-7/10

Claims (4)

(57) [Claims] To 1. A machine body 21, to form a ceiling in the air inlet 22 and the ceiling air outlet 23 and the outside air inlet 24 and the outside air outlet 25, inside the body 21, prior to the ceiling in the air inlet 22
And the heat recovery air duct E communicating with the serial ceiling air outlet 23, to form a, the outside air processing air passage F that communicates with the outside air outlet 25 and the <br/> outside air inlet 24, the outside air from the outside air inlet 24 the <br/> sensible heat exchanger 26 or the total heat exchanger for heat exchange with the ceiling in the air from the ceiling air inlet 22, before said heat recovery air path E and
It provided across the serial outside air processing air duct F, before the aircraft 21
The outside air outlet 25 is a ceiling-mounted air-cooled heat pump type air conditioner 2
7 is connected to the outside air intake 6 directly or through a duct.
The heat recovery outside air from the outside air outlet 25 is supplied to the air conditioner 27.
This air-cooled heat pump type
An air supply port 7 is provided on one of the opposing end surfaces of the casing 1 of the air conditioner 27.
The exhaust intake port 8 is formed and the outer side is formed on the other of the opposite end faces.
In the casing 1, the intake port 6 and the exhaust port 10 are formed.
And a condenser communicating with the exhaust inlet 8 and the exhaust outlet 10.
4 and an air blower 5 provided with an air blower 5
Outside air blow passage communicating with the windward side of the condenser 4 in the air blow passage B
C, one end communicates with the air supply port 7, and the evaporator 2 and the blower
3 and the exhaust air from the exhaust air passage B
The outside air of the outside air blowing passage C and the outside air of the supply air blowing passage A are respectively
And a damper mechanism D capable of freely adjusting the air volume,
The air passage C is sandwiched between the air supply air passage A and the exhaust air passage B.
In parallel with each other, and in addition to the outside air blow passage C,
The outside air is straddled over the end portion and the other end portion of the supply air duct A.
An in-ceiling heat recovery machine characterized by having the intake ports 6 communicated with each other. 2. An air inlet 22 in the ceiling and a ceiling in the airframe 21.
The inner air outlet 23, the outer air inlet 24, and the outer air outlet 25 are formed.
However, inside the airframe 21, the air inlet 22 in the ceiling and the front
The heat recovery air passage E communicating with the air outlet 23 in the ceiling;
Outside air processing wind communicating with the outside air inlet 24 and the outside air outlet 25
Forming a path F and connecting the outside air from the outside air inlet 24 with the outside air.
A heat exchanger that exchanges heat with the air in the ceiling from the air inlet 22 in the ceiling.
Install the heat exchanger 26 or the total heat exchanger in front of the heat recovery air passage E.
Installed over the outside air processing air passage F, in front of the machine body 21.
The outside air outlet 25 is a floor-standing air-cooled heat pump type air conditioner 2
7 is connected to the outside air intake 6 directly or through a duct.
The heat recovery outside air from the outside air outlet 25 is supplied to the air conditioner 27.
This air-cooled heat pump type
Air inlet 7 and exhaust intake on one end surface of casing 1 of controller 27
The port 8, the outside air intake 6 and the exhaust port 10 are formed, and
The exhaust inlet 8 and the exhaust outlet 10 in the housing 1.
An exhaust air blow passage B provided with a communicating condenser 4 and a blower 5,
The outside air intake 6 and the air supply port 7 are communicated with each other, and the evaporator 2 and the air are blown.
Of the air supply air passage A provided with the machine 3 and the exhaust air passage B
On the windward side of the evaporator 4 and on the windward side of the evaporator 2 in the air supply air passage A
The outside air blow passage C communicating with the exhaust air from the exhaust blow passage B and the front
The outside air of the outside air blow passage C and the outside air of the above-mentioned supply air blow passage A are respectively
A damper mechanism D capable of adjusting the air volume,
The passage A and the exhaust air passage B are formed so as to make a U-turn.
The heat recovery machine in the ceiling is characterized by being adjacent to each other in parallel . 3. A sensible heat exchanger 26 has a four
The rectangular tubular frame 28 and the pair of facing surfaces of the rectangular tubular frame 28 are
Heat transfer tube group 2 that is inserted so as to penetrate and allows air to pass through inside
9. The in-ceiling heat recovery machine according to claim 1 or 2, further comprising: 4. An in-ceiling air inlet 22 is provided on one side of the airframe 21.
The air outlet 23 in the ceiling is arranged close to the airframe, and
The in-ceiling heat recovery machine according to claim 1, 2 or 3 , wherein the outside air outlet 25 and the outside air inlet 24 are arranged close to each other .