JP2020046116A - Heat exchange assist device - Google Patents

Abstract

To assist heat exchange of a heat source side air heat exchanger of a heat source device efficiently.SOLUTION: A heat exchange assist device includes: a blower 10; a radiator 20 which causes air received from the blower 10 to pass therethrough and conducts heat exchange between the air and hot and chilled water supplied from the outside; a first duct part 40 which takes the air that has passed through the radiator 20 thereinto and causes the air to circulate; and an air discharge part 50 which is connected to the downstream side of the first duct part 40 and discharges the air in the first duct part 40. The air discharge part 50 is provided so as to blow air onto an air suctioning surface of a heat source side air heat exchanger a1 of a heat source device A.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a heat exchange auxiliary device that assists heat exchange of a heat source side air heat exchanger in an existing heat source device having a refrigeration cycle, such as a chiller, a refrigerator, a showcase, an air conditioner, and a water heater. is there.

The operation of an air-cooled outdoor unit such as a cooling / heating unit and a refrigerator is always affected by the outside air temperature. In particular, in the cooling operation in summer, the energy consumption increases as the outside air temperature increases. Conversely, in the heating operation in winter, the energy consumption increases as the outside air temperature decreases. In addition, in snowy countries, there is a problem that snow adheres to the air heat exchanger and freezes, and a wasteful defrost operation is frequently performed and the heating operation is interrupted.
Therefore, it is conceivable to change the outdoor unit to a water-cooled type, but it is not practical because existing equipment is wasted and the initial cost is enormous.

  In order to solve such a problem, for example, in the invention described in Patent Document 1, an air conditioner constituting a refrigeration cycle and an auxiliary device for circulating water stored in a water storage tank to an auxiliary air heat exchanger are provided. The auxiliary air heat exchanger is brought close to the outdoor heat exchanger of the air conditioner, and the air once subjected to heat exchange by the auxiliary air heat exchanger is passed through the outdoor heat exchanger and heat exchanged again. Thus, the refrigeration cycle is less likely to be adversely affected by the outside air temperature and the efficiency of the refrigeration cycle is improved.

JP-A-2005-78813

However, according to the above prior art, it is necessary to arrange the auxiliary air heat exchanger near the outdoor heat exchanger of the air conditioner. Therefore, for example, when there are many air conditioners, it is necessary to provide an auxiliary air heat exchanger for each outdoor heat exchanger of the air conditioner.
Further, when an air heat exchanger (plate fin coil) having a U-shaped cross section is provided on three sides, such as an air-cooled chiller, a U-shape is formed along the air heat exchanger. The necessity of arranging the auxiliary air heat exchanger arises, which complicates the configuration and increases the cost. Further, in any of the above aspects, there is a concern that the outside air may be subjected to resistance by the auxiliary air exchanger, the air hitting or passing through the auxiliary air heat exchanger may leak laterally, and the efficiency may be reduced. You.

In view of such a problem, the present invention has the following configuration.
A blower, a radiator for passing air received from the blower and exchanging heat with cold / hot water supplied from the outside, a first duct portion for taking in and passing the air passing through the radiator, and the first duct portion An air discharge unit connected to a downstream side of the first duct unit to discharge air in the first duct unit, wherein the air discharge unit blows air to an air suction surface of a heat source side air heat exchanger of a heat source device. A heat exchange assisting device provided in a heat exchanger.

  Since the present invention is configured as described above, it is possible to efficiently assist the heat exchange of the heat source-side air heat exchanger of the existing heat source equipment with a simple structure.

BRIEF DESCRIPTION OF THE DRAWINGS It is a top view which shows the principal part about the example of the heat exchange auxiliary apparatus which concerns on this invention, (a) shows the state before attaching a heat exchange auxiliary apparatus to a heat source apparatus, (b) is a heat exchange auxiliary apparatus. Shows the state after mounting on the heat source device. FIG. 1 is a schematic structural diagram showing a cross section of a main part of an example of a heat exchange auxiliary device according to the present invention. FIG. 4 is a schematic structural diagram showing a cross section of a main part of another example of the heat exchange auxiliary device according to the present invention. FIG. 4 is a schematic structural diagram showing a cross section of a main part of another example of the heat exchange auxiliary device according to the present invention.

In the present embodiment, the following features are disclosed.
The first feature is a blower, a radiator that passes air received from the blower and exchanges heat with cold / hot water supplied from the outside, and a first duct portion that takes in and circulates the air that has passed through the radiator, An air discharge unit connected to a downstream side of the first duct unit to discharge air in the first duct unit, wherein the air discharge unit is configured to suction air from a heat source side air heat exchanger of a heat source device. It is provided so as to blow air to the surface (see FIGS. 1 to 4).

  As a second feature, the air discharge unit is formed so as to be close to and cover the air suction surface of the heat source side air heat exchanger of the heat source device (see FIGS. 1 to 4). .

  The third feature is that a second duct portion that collects the air discharged from the heat source side air heat exchanger of the heat source device and returns the air to the suction side of the blower is provided (see FIG. 3).

  A fourth feature is that an air flow adjusting device is provided for adjusting the amount of air returned to the suction side of the blower by the second duct portion (see FIG. 3).

  A fifth feature is that the radiator has a cold / hot water circulation path for circulating cold / hot water, and the circulation water flow path includes a water heat exchanger for exchanging heat of the circulating cold / hot water with natural water, and a circulating cold / hot water. And a temporary storage tank for temporarily storing and then flowing (see FIGS. 2 to 4).

<First embodiment>
Next, a first embodiment having the above features will be described in detail with reference to the drawings.
1 and 2 show an example of a heat exchange auxiliary device according to the present invention.

  The heat exchange auxiliary device 1 includes a blower 10, a radiator 20 that passes air received from the blower 10 and exchanges heat with cold and hot water supplied from the outside, a collecting pipe unit 30 that takes in air that has passed through the radiator 20, A first duct section connected to the downstream side of the collecting pipe section to allow air to flow therethrough; and a plurality of first duct sections connected to the downstream side of the first duct section to discharge air supplied from the first duct section. , A cold / hot water circulation path 60 for circulating cold / hot water through the radiator 20, and a natural water circulation path 70 for exchanging heat with the cold / hot water circulation path 60. Air is blown onto the air suction surface of the air heat exchanger a1 to assist the heat exchange action of the heat source side air heat exchanger a1.

Here, a heat source device to be subjected to heat exchange assistance by the heat exchange assistance device 1 may be any device having a refrigeration cycle, such as a chiller, an air conditioner, a refrigerator, and a water heater. The heat source device can be a heat pump device, a device only for cooling, or a device only for heating.
The heat source device A illustrated in FIGS. 1 to 3 is an outdoor unit of a heat pump type air conditioner, and includes an air-cooled heat source side air heat exchanger a1 and a fan a2 for flowing air through the heat source side air heat exchanger a1. .
According to the illustrated example, the heat-source-side air heat exchanger a1 is formed by bending a substantially rectangular flat plate fin coil into a substantially L-shape when viewed from above.

  As the blower 10, for example, a propeller fan, a sirocco fan, a turbo fan, or the like can be used.

  The radiator 20 is provided with a number of heat exchange fins 21 arranged in a substantially parallel manner with an appropriate gap, and a water pipe 22 inserted in a meandering manner through these heat exchange fins 21. Heat exchange between the air flowing through the gap and the liquid (cold / hot water) flowing through the water pipe 22 is performed.

  The collecting pipe part 30 is formed so as to collect air on the delivery side of the radiator 20, and according to the illustrated example, a tubular part 31 that covers the side of the blower 10 and the radiator 20, and a downstream side of the tubular part 31. And a reduction pipe portion 32 connected to the cylindrical portion 31 to reduce the opening area, and the opening on the upstream side of the tubular portion 31 is used as a suction port.

The first duct portion 40 is a long cylindrical or rectangular tubular duct. The first duct section 40 is configured by appropriately connecting a straight tubular duct or an elbow-shaped duct according to the installation status of the plurality of heat source devices A.
The upstream side of the first duct section 40 communicates with the collecting pipe section 30, and the most downstream end is closed.

  The air discharge part 50 is provided so as to branch off to the peripheral wall surface of the first duct part 40. More specifically, the air discharge section 50 includes a branch pipe section 51 branched in a T-shape from the first duct section 40 and a hood section 52 connected to the downstream side of the branch pipe section 51. Prepare together.

  According to the illustrated example, the branch pipe portion 51 is a short straight pipe, but a pipe body having an appropriate length and shape according to the installation condition of the heat source device A, such as a long straight pipe or a bellows pipe. Is used.

The hood portion 52 is formed in a hood shape close to the air suction surface of the heat source side air heat exchanger a1 of the heat source device A and covering the air suction surface.
The hood portion 52 is formed in the shape of an enlarged pipe (diffuser) that expands downstream from the branch pipe portion 51, and the downstream end thereof has two suction surfaces that intersect with the heat source side air heat exchanger a1. Is covered in an L-shape (see FIGS. 1 to 3).

  The outer surface side of the collecting pipe part 30, the first duct part 40, and the air discharge part 50 is heat-insulated by a heat insulating material. As the heat insulating material, for example, urethane foam, glass wool, or other known heat insulating materials can be used.

  Further, the cold / hot water circulation path 60 is provided in the circulation path connected to the pipe with the secondary portion of the radiator 20 and the secondary liquid (cool / hot water) with the natural water and natural water on the natural water circulation path 70 side. The apparatus includes a water heat exchanger 61 to be exchanged, a temporary storage tank 62 for temporarily storing and circulating a liquid circulating on the secondary side, and a pump 63 for forcibly conveying cold and hot water (see FIG. 2).

The water heat exchanger 61 is a plate-type heat exchanger that exchanges heat between natural water on the primary side (for example, groundwater or the like) and liquid on the secondary side (for example, anti-corrosion antifreeze or water) through a number of plates. It is a heat exchanger.
The primary side of the water heat exchanger 61 is connected to a pipe constituting a natural water circulation path 70 described later, and the secondary side thereof is connected to a pipe constituting a cold / hot water circulation path 60.

The temporary storage tank 62 is a hollow sealed tank having a side wall and upper and lower walls, and a pipe on the downstream side of the water heat exchanger 61 is connected to an upper side thereof. A discharge port is provided at a lower side of the temporary storage tank 62, and a pipe leading to an inlet of the radiator 20 via a pump 63 is connected to the discharge port.
In the temporary storage tank 62, the inner diameter of the discharge port is made smaller than the inner diameter of the inflow side pipe so that the supplied liquid is temporarily stored and then gradually discharged at a constant rate.
As another example, a water level sensor detects that the amount of water stored in the temporary storage tank 62 has become equal to or more than a predetermined amount, and the discharge port is opened by an electric valve in accordance with the detection state. It is also possible to adopt a mode in which the discharge port is opened by a float valve when the amount of water stored in 62 becomes equal to or more than a predetermined amount.

  The natural water circulation path 70 forcibly places the primary part of the radiator 20 described above, the groundwater recirculation device 71 embedded in the ground, and the liquid of the primary side on the surface of the ground in a circulation path connected by piping. And a pump 72 for carrying. The pump 72 may be replaced with a submersible pump provided in the underground groundwater recirculation device 71 as necessary.

The groundwater recirculation device 71 is a device that sucks groundwater from a groundwater vein, exchanges the heat of the groundwater with the water heat exchanger 61, and returns the heat to the groundwater vein. As the underground water return device 71, for example, an underground device disclosed in JP-A-2006-9335 can be used.
In addition, as another example, this groundwater recirculation device 71 is configured to pump river water or lake water and distribute it to the water heat exchanger 61, or to pump rainwater stored in a rainwater tank by a pump to use the water heat exchanger 61. It is also possible to replace it with a configuration that allows it to be distributed.

Next, the characteristic operation and effect of the heat exchange auxiliary device 1 having the above configuration will be described in detail.
As shown in FIGS. 1A and 1B, the heat exchange auxiliary device 1 having the above configuration is used such that a plurality of air discharge units 50 are mounted on a plurality of heat source devices A.

In the mounted state, while circulating the cold and hot water in the cold and hot water circulation path 60 and circulating the natural water in the natural water circulation path 70 and blowing the air by the blower 10, the outside air flows into the collecting pipe section 30 through the blower 10. And heat is exchanged by the radiator 20. Then, the air after the heat exchange passes through the first duct portion 40 and is blown from each air discharge portion 50 to the heat source side air heat exchanger a1 of the heat source device A.
Therefore, on the heat source device A side, better air heat exchange can be performed as compared with the case where the heat source side air heat exchanger a1 is directly in contact with the outside air.

  For example, when the heat source device A (the outdoor unit of the heat pump air conditioner) is performing the cooling operation, the groundwater at a temperature of about 15 ° C. is pumped up by the groundwater recirculation device 71 and circulated through the natural water circulation path 70, and the heat of the groundwater is Is transmitted to the natural water circulation path 70 and the cold / hot water circulation path 60, if the outside air is higher than the temperature of the groundwater, the outside air is cooled by the radiator 20, and the cold air is sent to each of the high-temperature heat source side air heat exchangers a1. Since it can be sprayed, the cooling efficiency of the heat source device A can be improved.

  During the heating operation by the heat source equipment A, the groundwater at a temperature of about 15 ° C. is pumped up by the groundwater recirculation device 71 and circulated through the natural water circulation path 70, and the heat of the groundwater is transferred to the natural water circulation path 70 and the cold / hot water circulation path 60. When the outside air is lower than the temperature of the groundwater, the outside air is heated by the radiator 20 and the hot air can be blown to each of the low-temperature heat-source-side air heat exchangers a1. Heating efficiency can be improved. It is known that the temperature of groundwater is kept constant to some extent throughout the year.

  Further, according to the heat exchange auxiliary device 1, the air discharge unit 50 is provided so as to cover the air suction surface of the heat source side air heat exchanger a1. For this reason, when the heat source device A performs the heating operation in winter, it is possible to prevent the low-temperature heat-source-side air heat exchanger a1 from being directly exposed to the cool air, and as a result, frost or It is possible to prevent the unnecessary defrost operation from being frequently repeated due to the adhesion of snow.

  Therefore, according to the heat exchange auxiliary device 1 of the present embodiment, it is not necessary to provide a plurality of auxiliary air heat exchangers in accordance with the plurality of heat exchangers as in the related art, and the existing heat source has a simple structure. The heat exchange of the heat source side air heat exchanger a1 of the equipment A can be efficiently assisted, and the operation efficiency of each heat source equipment A can be improved.

<Second embodiment>
Next, a second embodiment will be described.
In addition, since the embodiment shown below added or changed the structure with respect to the above-described heat exchange auxiliary device 1, mainly the details of the added and changed parts will be mainly described in detail, and will be described in common. The overlapping detailed description of the parts will be omitted.

  The heat exchange auxiliary device 2 shown in FIG. 3 is different from the above heat exchange auxiliary device 1 in that the collecting pipe section 30 is replaced with a collecting pipe section 30 ′, and is discharged from the heat source side air heat exchanger a1 of the heat source device A. A collection pipe 110 for collecting air, a second duct 120 for returning the air collected by the collection pipe 110 to the suction side of the blower 10, and an amount of air returned to the suction side of the blower 10 by the second duct 120 And an air flow adjusting device 130 for adjusting the pressure.

  The collecting pipe part 30 ′ is obtained by adding a suction part 33 and a suction pipe 34 to the collecting pipe part 30 ′.

The suction portion 33 is formed in an enlarged tubular shape that covers the suction side of the blower 10 and expands downstream, and is integrally connected to the tubular portion 31.
The suction pipe 34 is a pipe body connected in a straight tubular shape on the upstream side of the suction section 33, and has an upstream suction port opened.
Inside the suction pipe 34, a first damper device 131 and an outside air temperature sensor 134, which constitute an air flow control device 130 described later, are provided.

  The outside air temperature sensor 134 is, for example, a temperature sensor using a resistance temperature detector or the like, measures the outside air temperature upstream of the first damper device 131, and sends an electric signal indicating the outside air temperature to a control circuit (not shown). send.

  In addition, as another example, a mode in which a gap is provided between the suction portion 33 and the tubular portion 31 or a mode in which air discharged from the suction pipe 34 is blown to the blower 10 by omitting the suction portion 33 may be used. It is possible.

The recovery pipe 110 covers a downstream side of the fan a2 of the heat source device A and is reduced toward the downstream side. The recovery pipe 110 is connected to the downstream side of the reduction pipe section 111 and connected to the second duct section 120. A converging tube portion 112 connected so as to converge with the converging portion is integrally provided.
According to the illustrated example, the reduction pipe section 111 is configured separately from the air discharge section 50; however, as another example, the reduction pipe section 111 can be configured integrally with the air discharge section 50.
Although the merging tube portion 112 is formed in a straight tube according to the illustrated example, it may be in a mode according to site conditions, such as a bellows tube or an elbow tube.

  The second duct portion 120 includes a long duct main body 121 extending in the direction in which the plurality of heat source devices A are arranged, and a return pipe portion 122 connected to the downstream side of the duct main body 121 and heading toward the suction side of the blower 10. To form a continuous air flow path.

The most upstream side of the duct main body 121 (the portion (not shown) on the right end side in FIG. 3) is closed.
The most downstream side of the duct main body 121 communicates with the outside air via a third damper device 133 that constitutes an air flow control device 130 described later.

The return pipe section 122 is a pipe body that is branched in a T-shape from the peripheral wall on the downstream side of the duct main body 121 and on the upstream side of the third damper device 133. The downstream end of the return pipe 122 is connected to the peripheral wall of the suction pipe 34, and forms a flow path for returning the air in the second duct 120 to the suction pipe 34.
In the return pipe section 122, a return air temperature sensor 122a and a second damper device 132 described later are provided.

  The duct main body 121, the return pipe section 122, the suction section 33, the suction section 33 and the like are heat-insulated in the same manner as the first duct section 40 and the like.

  The return air temperature sensor 122a is a temperature sensor using, for example, a resistance temperature sensor or the like, measures the temperature of air in the second duct unit 120, and sends an electric signal corresponding to the temperature to a control circuit (not shown). .

  The air flow adjusting device 130 is provided at a first damper device 131 provided on the upstream side of the return pipe 122 in the suction pipe 34 and on a downstream side of the return air temperature sensor 122 a in the return pipe 122. A second damper device 132, a third damper device 133 provided downstream of the branch of the return pipe portion 122 in the duct main body 121, and a control circuit (not shown). The first to third damper devices 131, 132, 133 are appropriately controlled.

  Each of the first to third damper devices 131, 132, 133 includes a flow control plate p supported to rotate in a pipe, and an electric motor (not shown) for rotating the flow control plate p. It becomes. The flow rate adjustment plate p is provided between a position where air flows through the pipe (for example, a position substantially parallel to the central axis of the pipe) and a position where the flow of air in the pipe is interrupted (for example, a position substantially orthogonal to the central axis of the pipe). Rotate approximately 90 degrees between them. The electric motor includes, for example, a stepping motor, a servomotor, or the like, and adjusts a rotation angle of the flow rate adjustment plate p according to a command from the control circuit.

Next, the characteristic operation and effect of the heat exchange auxiliary device 2 having the above configuration will be described in detail.
According to the heat exchange auxiliary device 2, the operation efficiency of each heat source device A can be improved by utilizing the heat of the groundwater in the same manner as the heat exchange auxiliary device 1 described above.
In addition, in the heat exchange auxiliary device 2, the exhaust heat of each heat source device A can be reused by the second duct portion 120.

More specifically, when the first damper device 131 is fully closed, the second damper device 132 is fully opened, and the third damper device 133 is fully closed, the first damper device 131 is fully closed by the control of the air flow rate adjusting device 130. An air circulation path is formed in the duct section 40 and the second duct section 120 (hereinafter, referred to as a circulation mode).
When the first damper device 131 is fully opened, the second damper device 132 is fully closed, and the third damper device 133 is fully opened under the control of the air flow adjusting device 130, the outside air sucked into the suction pipe 34 Is discharged from the third damper device 133 to the outside without returning to the suction pipe 34 side after passing through each heat source device A (hereinafter, referred to as an open mode).

During the cooling operation of the heat source device A, the control circuit (not shown) initially sets the air flow control device 130 to the circulation mode, and compares the temperature of the outside air temperature sensor 134 with the temperature of the return air temperature sensor 122a.
When the temperature of the return air temperature sensor 122a is lower than the temperature of the outside air temperature sensor 134, the control circuit continues the circulation mode. When the temperature of the return air temperature sensor 122a becomes higher than the temperature of the outside air temperature sensor 134, the air flow control device 130 is set to the open mode, and the outside air having a relatively low temperature is positively taken in.

  In addition, when the heat source device A performs the heating operation, when the temperature of the return air temperature sensor 122a becomes lower than the temperature of the outside air temperature sensor 134 during the circulation mode, the air flow control device 130 is set to the open mode. Switch and actively take in relatively high temperature outside air.

  Therefore, according to the heat exchange auxiliary device 2, the exhaust heat of each heat source device A can be reused, the operation efficiency of each heat source device A can be effectively improved, and the discharge of the exhaust heat is small. There is little adverse effect on the environment.

  According to the heat exchange auxiliary device 2, the first to third damper devices 131, 132, and 133 are fully closed or fully opened. However, as another example, the first to third damper devices 131, 132, and 133 are used. It is also possible to adjust the opening amounts of 132 and 133 as appropriate.

<Third embodiment>
The heat exchange auxiliary device 3 shown in FIG. 4 replaces the heat exchange auxiliary device 1 with the heat source device A, which is the object of the heat exchange auxiliary, by the heat source device B. This is changed to an air discharge portion 50 'having a different shape.

  The heat source device B is an air-cooled heat pump chiller configured to discharge air sucked from three sides into the heat source-side air heat exchanger b1 having a substantially U-shape in a top view and exhausting the air upward by a top-side fan b2.

The air discharge part 50 'is formed by connecting a hood part 53 surrounding three side surfaces of the heat source side air heat exchanger b1 to the downstream side of the branch pipe part 51.
The hood portion 53 is formed so as to cover all three air suction surfaces of the heat source side air heat exchanger b1 and to cover an upper side of the heat source side air heat exchanger b1 with a top plate 55. The top plate 55 is provided with an exhaust hole 54 for the fan b2.

  Therefore, according to the heat exchange auxiliary device 3 having the above-described configuration, the operation efficiency of each heat source device A can be improved using the heat of the groundwater in the same manner as the heat exchange auxiliary device 1 described above.

In addition, as another example of the air discharge unit 50 ′ (see FIG. 4), the top plate 55 may be omitted and the upper part may be substantially entirely opened.
In addition, according to the illustrated example, the air discharge unit 50 ′ is formed so as to cover the three side surfaces of the heat source device A. However, as another example of the air discharge unit 50 ′, the four side surfaces of the heat source device A are formed. It is also possible to form so as to cover.

  Further, in the heat exchange assisting devices 1, 2, 3 described above, an axial fan is provided at an appropriate position in the first duct portion 40 and / or the second duct portion 120 to control the flow of air in the duct. You may make it assist.

  Further, in the above embodiment, the heat source devices A and B are heat pump type devices. However, as another example, these heat source devices may be a cooling only device, a heating only device, a water heater having a refrigeration cycle, or the like. is there.

  Further, in the above embodiment, the heat exchange auxiliary devices 1, 2, or 3 are configured in correspondence with the plurality of heat source devices A or B of the same type. It is also possible to constitute a heat exchange assisting device.

  Further, the present invention is not limited to the above-described embodiment, and can be appropriately changed without changing the gist of the present invention.

1, 2, 3: heat exchange auxiliary device 10: blower 20: radiator 30: collecting pipe 40: first duct 50: air discharge 60: cold / hot water circulation path 61: water heat exchanger 62: temporary storage tank 63 , 72: pump 70: natural water circulation path 71: groundwater recirculation device 120: second duct section 122a: return air temperature sensor 130: air flow control device 131, 132, 133: first to third damper device 134: outside Air temperature sensor A, B: Heat source equipment a1, b1: Heat source side air heat exchanger a2, b2: Fan

Claims (5)

A blower, a radiator for passing air received from the blower and exchanging heat with cold / hot water supplied from the outside, a first duct portion for taking in and passing the air passing through the radiator, and the first duct portion An air discharge unit connected to the downstream side of the first duct unit to discharge air in the first duct unit,
The heat exchange auxiliary device, wherein the air discharge unit is provided so as to blow air to an air suction surface of a heat source side air heat exchanger of a heat source device.   2. The heat exchange assisting device according to claim 1, wherein the air discharge unit is formed so as to be close to and cover the air suction surface of the heat source side air heat exchanger of the heat source device. .   The heat source according to claim 1 or 2, further comprising a second duct portion that collects air discharged from a heat source side air heat exchanger of the heat source device and returns the air to a suction side of the blower. Replacement aid.   The heat exchange assisting device according to any one of claims 1 to 3, wherein an air flow rate adjusting device that adjusts an amount of air returned to the suction side of the blower by the second duct portion is provided. The radiator has a cold / hot water circulation path for circulating cold / hot water, and in this circulation water passage, a water heat exchanger for exchanging heat of the circulating cold / hot water with natural water, and temporarily storing the circulating cold / hot water. The heat exchange auxiliary device according to any one of claims 1 to 4, further comprising a temporary storage tank for flowing.

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