SE1451397A1

SE1451397A1 - Radiation-type air conditioner

Info

Publication number: SE1451397A1
Application number: SE1451397A
Authority: SE
Inventors: Itaru Nagata
Priority date: 2012-05-23
Filing date: 2013-05-23
Publication date: 2014-11-20
Also published as: CN104380002A; WO2013176211A1; CN104380002B; JP2013245830A; JP5869955B2

Description

Patent Literature

[0004] Patent Literature l: JP-A-H10-205 802 Summary of Invention Technical Problem

[0005] lt is true for air conditioners in general that when a Compressor is in operation, refrigerant pressure is high on a discharge side of the Compressor and low on a suction side of the Compressor. When the operation of the Compressor is stopped, the refrigerant moves from a high-pressure area to a low-pressure area to balance the pressure in a refrigeration Cycle. In a radiation-type air Conditioner, when a Compressor stops operating during a Cooling operation, for example, a refrigerant of a low temperature moves out of a radiation panel while a refrigerant of a high temperature ﬂows into the radiation panel to raise the temperature of the radiation panel, and thereby once Cooled indoor air is warrned. When a Compressor stops its operation during a heating operation, a refrigerant of a high temperature moves out of the radiation panel while a refrigerant of a low temperature ﬂows into the radiation panel to lower the temperature of the radiation panel, and thereby once warmed indoor air is Cooled by the radiation panel of the lowered temperature.

[0006] The present invention has been made in view of the above problems, and an object of the present invention is to provide a radiation-type air Conditioner Capable of maintaining Cooling and heating effects as long as possible after a Compressor is stopped during Cooling and heating operations.

Solution to Problem

[0007] According to the present invention, a radiation-type air Conditioner includes: _ 3 _ a radiation panel placed indoors, an outdoor heat exchanger, a Compressor that circulates a refrigerant in the radiation panel and the outdoor heat exchanger via a refrigerant pipe, a controller, and a valve arranged in the refrigerant pipe connected to the radiation panel.

Here, While stopping the compressor in operation, the controller brings the valve into a small opening state.

[0008] In the radiation-type air conditioner configured as described above, it is preferable that each of an inlet side and an outlet side of the radiation panel is provided With the refrigerant pipe, and the valve is disposed at each of the refrigerant pipes on the inlet and outlet sides of the radiation panel.

[0009] In the radiation-type air conditioner configured as described above, it is preferable that the valve be an expansion valve.

[0010] In the radiation-type air conditioner configured as described above, it is preferable that the small opening state includes a fully closed state.

Advantageous Effects of Invention

[0011] According to the present invention, While stopping a compressor in operation, a valve in a refrigerant pipe is brought into a small opening state, and this prevents a refrigerant in the refrigerant pipe from moving easily, and thus temperature of the radiation panel does not change abruptly. This helps maintain cooling and heating effects brought about by the radiation panel.

Brief Description of the Drawings

[0012] Fig. l is a schematic configuration diagram of a radiation-type air conditioner according to the present invention, showing a state during a cooling operation; _ 4 _ Fig. 2 is a schematic configuration diagram of the radiation-type air Conditioner according to the present invention, showing a state during a heating operation; Fig. 3 is a schematic configuration diagram showing a ﬁrst embodiment of a radiation panel; Fig. 4 is a schematic configuration diagram showing a second embodiment of the radiation panel; Fig. 5 is a sectional view showing a first embodiment of a radiator; Fig. 6 is a sectional view showing a second embodiment of the radiator; and Fig. 7 is a control block diagram of the radiation-type air conditioner.

Description of Embodiments

[0013] On the basis of Fig. 1, descriptions will be given of a schematic configuration of a radiation-type air conditioner 1. The radiation-type air conditioner is conﬁgured with an outdoor unit 10 and a radiation panel 30. The radiation panel 30 is placed indoors and is equivalent to an indoor unit of a typical separate-type air conditioner.

[0014] The outdoor unit 10 includes a housing 11 in which a compressor 12, a four- way valve 13, an outdoor heat exchanger 14, an expansion valve 15, and an outdoor blower 16 are accommodated. As the expansion valve 15, there is used one whose opening is controllable.

[0015] The outdoor unit 10 is connected to the radiation panel 30 via two refrigerant pipes 17 and 18. The refrigerant pipe 17 is provided for a refrigerant in a liquid state, and a pipe used as the refrigerant pipe 17 is of a smaller diameter than a pipe used as the refrigerant pipe 18. Thus, the refrigerant pipe 17 may also be referred to as, for example, a “liquid pipe” or a “thin pipe”. The refrigerant pipe 18 is provided for a refrigerant in a gas state, and _ 5 _ the pipe used as the refrigerant pipe 18 is of a larger diameter than the pipe used as the refrigerant pipe 17. Thus, the refrigerant pipe 18 may also be referred to as, for example, a “gas pipe” or a “thick pipe”. Used as the refrigerant is, for example, R4l0a or R32 in HFC family.

[0016] Among refrigerant pipes provided inside the outdoor unit 10, one that is connected to the refrigerant pipe 17 is provided With a two-Way valve 19, and one that is connected to the refrigerant pipe 18 is provided With a three-Way valve 20. The two-Way valve 19 and the three-Way valve 20 are closed When the refrigerant pipes 17 and 18 are detached from the outdoor unit 10, and thereby, leakage of the refrigerant to outside the outdoor unit 10 is prevented. When it is necessary to discharge the refrigerant from the outdoor unit 10 or from the entire refrigeration cycle including the radiation panel 30, the discharge of the refrigerant is carried out through the three-Way valve 20. In the refrigerant pipe between the three-Way valve 20 and the four-Way valve 13, there is provided an electromagnetic valve 25.

[0017] The radiation panel 30 is often provided to stand close to a Wall in a room.

The radiation panel 30 is such that a plurality of radiators 32 are arranged inside a housing 31 that is configured With sheet metal components and plastic components and is rectangular in front view. The radiators, Which are named as such for simplicity, are each a component that not only radiates heat into the ambient air in a heating operation but also absorbs heat from the ambient air in a cooling operation.

[0018] The radiators 32 are vertically arranged cylindrical components. As shoWn in Figs. 5 and 6, the radiators 32 are each basically configured such that a refrigerant pipe 33 located in a center is surrounded by a radiation fin 34. The refrigerant pipe 33 and the radiation fin 34 are formed from a highly heat conductive metal such as copper and aluminum, _ 6 _ and the refrigerant pipe 33 and the radiation fin 34 ﬁrmly adhere to each other. It should be noted that the term °vertically” and its derivatives as used herein are not intended to limitedly refer to a strictly vertical direction. The vertical direction may be a direction that slightly leans from the strictly vertical direction.

[0019] The radiation ﬁn 34 of Fig. 5 and the radiation fin 34 of Fig. 6 are both shaped such that a plurality of fins are radially arranged. The radiation fin 34 of Fig. 5 is formed as a component that is divided into two parts along an axial direction thereof, and the two parts are located in front of and behind the refrigerant pipe 33 so as to sandwich the refrigerant pipe 33. The radiation fin 34 of Fig. 6 is a single component, having the refrigerant pipe 33 placed in a central part thereof that is a part comparable to the hub of a wheel. Needless to say, the structures of the radiators 32 shown in Figs. 5 and 6 are mere examples; a radiation fin 34 having a different sectional shape may be used, or, the refrigerant pipe 33 and the radiation fin 34 may be combined in a different manner.

[0020] Inside the housing 31, a plurality of (in the figures, seven) radiators 32 are arranged parallel to each other. In a front portion of the housing 31, there is provided an opening 35 through which the radiators 32 are exposed. The plurality of radiators 32 are all connected to the refrigerant pipes 17 and 18. In an example of a connection configuration shown in Fig. 3, all the radiators 32 are connected in parallel to the refrigerant pipes 17 and 18.

In an example of the connection configuration shown in Fig. 4, a set of the radiators 32 that are all connected in series to each other is connected to the refrigerant pipes 17 and 18.

[0021] Connection of the plurality of radiators 32 may be achieved by means of a method other than those shown in Figs. 3 and 4. For example, there may be adopted a method where the plurality of radiators 32 are divided into groups of a predeterrnined number, the radiators 32 belonging to the same group are connected in parallel to each other, and the _ 7 _ groups are connected in series to each other. Or, another possible method is such that the plurality of radiators 32 are divided into groups of a predetermined number, the radiators 32 belonging to the same group are connected in series to each other, and the groups are connected in parallel to each other.

[0022] For performing operation control of the radiation-type air conditioner 1, it is indispensable to obtain inforrnation of temperatures of various portions. For this purpose, the outdoor unit 10 and the radiation panel 30 are provided with therrnometric devices. In the outdoor unit 10, a therrnometric device 21 is arranged at the outdoor-side heat exchanger 14, a therrnometric device 22 is arranged at a discharge pipe 12a which is a discharge portion of the compressor 12, a therrnometric device 23 is arranged at a suction pipe 12b which is a suction portion of the compressor 12, and a therrnometric device 24 is arranged at the refrigerant pipe between the expansion valve 15 and the two-way valve 19. A therrnometric device 36 is arranged at the radiation panel 30. The therrnometric devices 21, 22, 23, 24, and 36 are each a therrnistor.

[0023] Although the therrnometric device 36 is provided for the purpose of measuring the temperature of the radiators 32, the therrnometric device 36 is not attached directly to the radiators 32, but as shown in Fig. 3, it is attached to the refrigerant pipe 17 for the refrigerant in the liquid state. The therrnometric device 36 is arranged on the refrigerant pipe 17 for the following reason. That is, the temperature of the radiators 32 differs depending on where (in an up-down direction in particular) in the radiators 32 it is measured, and this makes it difficult to decide where to arrange the therrnometric device 36.

[0024] Surface temperature of the radiators 32 depends also on a design of a refrigerant path that connects the plurality of radiators 32. In a case where the refrigerant path is a single path, difference is liable to be caused in surface temperature of the radiators _ g _ 32 by, for example, a pressure loss or a gas-liquid phase change of the refrigerant. In a case Where the refrigerant path includes a plurality of paths, different paths may have different temperatures. What is more, some therrnometric devices are covered With metal for a high therrnosensitivity. In a case Where the metal forrning the radiators 32 is different from the metal used in the therrnometric device, a potential difference is caused between the different metals Where they contact each other, and the potential difference may cause electric corrosion. In Whichever of these cases, it is not easy at all to decide Where in the radiators 32 to arrange the therrnometric device 36.

[0025] By choosing a position along the refrigerant pipe 17 inside the housing 31 as a ﬁtting position of the therrnometric device 36, the above problem can be solved. The refrigerant pipe 17 is a place into Which the refrigerant throttled by the expansion valve 15 ﬂoWs during the cooling operation, and into Which a condensed refrigerant ﬂoWs from the radiators 32 during the heating operation.

[0026] During the cooling operation, a gas-liquid two-phase refrigerant (Where vaporization has not proceeded much and thus the liquid-phase refrigerant is predominant in amount) ﬂoWs in the refrigerant pipe 17, in other Words, gas-liquid phase change of the refrigerant has not taken place much, and thus, the temperature of the refrigerant pipe 17 can be treated as the temperature of the radiators 32. On the other hand, during the heating operation, the refrigerant pipe 17 becomes a supercooling portion (liquid-phase portion) Where the refrigerant in the liquid state collects, and thus, the temperature of the refrigerant pipe 17 cannot be treated as it is as the temperature of the radiators 32. HoWever, through appropriate temperature correction, it is possible in the heating operation as Well to obtain the surface temperature of the radiators 32 from the temperature measured by the therrnometric device 36. Corrected temperature values are deterrnined through experiments. _ 9 _

[0027] As for the ﬁtting position of the therrnometric device 36, the thermometric device 36 is preferably ﬁtted to a comparatively upper part of the refrigerant pipe 17 inside the housing 31. A description of Why such a position is chosen as the ﬁtting position of the therrnometric device 36 Will be described later.

[0028] It is a controller 40 shoWn in Fig. 7 that perforrns an overall control of the radiation-type air conditioner 1. The controller 40 controls such that a room temperature reaches a desired value set by a user.

[0029] The controller 40 gives operation instructions to the compressor 12, the four- Way valve 13, the expansion valve 15, the outdoor-side bloWer 16, and the electromagnetic valve 25. The controller 40 receives output signals indicating detected temperatures from the therrnometric devices 21-24 and the thermometric device 36. Referring to the output signals received from the therrnometric devices 21-24 and the thermometric device 36, the controller 40 instructs the compressor 12 and the outdoor-side bloWer 16 to be activated, and instructs the four-Way valve 13, the expansion valve 15, and the electromagnetic valve 25 to switch their states.

[0030] Fig. 1 shoWs a state Where the radiation-type air conditioner 1 is performing the cooling operation (dehumidiﬁcation operation) or a defrosting operation. A high- temperature, high-pressure refrigerant discharged from the compressor 12 enters the outdoor heat exchanger 14, Where heat exchange is performed between the refrigerant and outdoor air.

That is, the refrigerant radiates heat With respect to the outdoor air. The refrigerant that has been condensed into the liquid phase is sent from the outdoor heat exchanger 14 through the expansion valve 15 to the radiators 32 of the radiation panel 30, Where the refrigerant is decompressed and expanded into a low-temperature, low-pressure refrigerant, Which lowers the surface temperature of the radiators 32. The radiators 32 Whose surface temperature has _ 10 _ been lowered absorb heat from indoor air, and thereby the indoor air is cooled. After the heat absorption, the low-temperature refrigerant in the gas state returns to the compressor 12.

An airﬂow generated by the outside blower 16 accelerates the heat radiation from the outdoor heat exchanger 14.

[0031] Fig. 2 shows a state where the radiation-type air conditioner 1 is perforrning the heating operation. At this time, the four-way valve 13 is switched so that the refrigerant ﬂows in a direction opposite to the direction in which the refrigerant ﬂows in the cooling operation. That is, the high-temperature, high-pressure refrigerant discharged from the compressor 12 enters the radiators 32, where heat exchange is performed between the refrigerant and the indoor air. That is, the refrigerant radiates heat with respect to the indoor air, and thereby the indoor air is warrned. The refrigerant that has radiated heat and condensed into the liquid state is sent from the radiators 32 via the expansion valve 15 to the outdoor heat exchanger 14, where the refrigerant is decompressed and expanded to lower the surface temperature of the outdoor heat exchanger 14. The outdoor heat exchanger 14 whose surface temperature has been lowered absorbs heat from the outdoor air. After the heat absorption, the refrigerant at a low-temperature and in the gas state returns to the compressor 12. An airﬂow generated by the outdoor blower 16 accelerates the heat absorption by the outdoor-side heat exchanger 14. Frost formed on the outdoor heat exchanger 14 through the heat absorption is removed by performing the defrosting operation.

[0032] during the heating operation, temperature detection is performed by the therrnometric device 36. As already mentioned above, the therrnometric device 36 is arranged at the refrigerant pipe 17, and thus is not intended to directly detect the surface temperature of the radiation panel 30 (more specifically, the surface temperature of the radiators 32). Moreover, difference between the temperature of the refrigerant pipe 17 and _ 11 _ the surface temperature of the radiation panel 30 depends on What value a degree of supercooling takes. So, in the heating operation, the surface temperature of the radiation panel 30 is predicted by predicting the degree of supercooling of the radiators 32 from the temperature of the refrigerant pipe 17 and correcting the temperature. As already mentioned above, corrected temperature values are obtained in advance through experiments.

[0033] As described above, the controller 40 controls the heating operation of the radiation-type air conditioner 1, referring to the surface temperature of the radiation panel 30 obtained by correcting the temperature detected by the therrnometric device 36.

[0034] During the heating operation, the controller 40 checks Whether or not the temperature of the radiation panel 30 has reached a high temperature that is over a set temperature. The therrnometric device 36 can be used for the temperature detection in this case as Well. Thus, by using the therrnometric device 36 to check Whether or not the temperature of the radiation panel 30 has reached a temperature over the set temperature, that is, by using the therrnometric device 36 for air-conditioning control also as a therrnometric device for protection, it is possible to achieve a simple control system for the radiation-type air conditioner l.

[0035] In the cooling operation (dehumidification operation) or the defrosting operation, the temperature detected by the therrnometric device 36 can be treated as the surface temperature of the radiators 32. Accordingly, unlike in the heating operation, temperature correction is not necessary.

[0036] As already described, the therrnometric device 36 is ﬁtted to a part of the refrigerant pipe 17 inside the housing 31, and thus, regardless of Whether the refrigerant path in the radiation panel 30 is ﬁanctioning as the refrigerant path in the cooling operation or as the refrigerant path in the heating operation, it is possible to detect the surface temperature of _ 12 _ the radiation panel 30 at the same position. This eliminates the need of changing the speciﬁcations of control between the cooling operation and the heating operation.

[0037] During the cooling operation (defrosting operation), condensate Water is formed at the radiators 32. Since the thermometric device 36 is ﬁtted to a comparatively upper part of the refrigerant pipe 17 inside the housing 31, even if the condensation Water formed at the radiators 32 accumulates as drain Water below the radiators 32 (drain Water is received in an unillustrated drain pan Which is arranged below the radiators 32), the therrnometric device 36 can stay out of contact With the drain Water. This eliminates concern over erroneous temperature detection by the therrnometric device 36 or over failure of the therrnometric device 36. Although not so much as at the radiators 32, condensation Water is formed at the refrigerant pipe 17 as Well, and for the purpose of reducing inﬂuence of such condensation Water as Well, it is important to arrange the therrnometric device 36 at the upper part of the refrigerant pipe 17.

[0038] In a case Where the plurality of radiators 32 are connected in series to each other as in Fig. 4, the therrnometric device 36 is arranged at the upper part of the refrigerant pipe 17. What is essential is that the therrnometric device 36 must be arranged at a place Where condensate Water is hard to be formed.

[0039] During the cooling operation (defrosting operation) or When a need arises of stopping the compressor 12 during the heating operation, the controller 40 sWitches the expansion valve 15 and the electromagnetic valve 25 to a small opening state. In this state, it is hard for the refrigerant to move, and accordingly the refrigerant in the radiation panel 30 does not move easily, and this makes it possible to avoid an abrupt change in the temperature of the radiation panel 30. As a result, the cooling and heating effects produced by the radiation panel 30 can be maintained. The “small opening state” is a concept that includes _ 13 _ the “ﬁilly closed state” as Well.

[0040] With a normal air Conditioner that is not of the radiation type, and that uses an indoor blower to circulate the indoor air, it is possible to keep the indoor blower in operation When stopping the compressor during the cooling operation. This allows a user to keep feeling cool. In contrast, With the radiation-type air conditioner, Which does not have a blower provided on the indoor side, it is impossible to enjoy a feeling of coolness brought about by a blower. If the refrigerant of the temperature at the time of the cooling operation is held in the radiation panel, although not in a lasting manner, a feeling of coolness is enjoyable. Likewise, in the case Where the refrigerant of the temperature at the time of the heating operation is held in the radiation panel, although not in a lasting manner, Warrnth is maintained. Thus, the method of sWitching a valve in a refrigerant pipe to a small opening state When stopping a compressor in operation exerts a prominent effect especially in a radiation-type air conditioner.

[0041] Furthermore, in comparison With a case Where pressure balance of the refrigerant is achieved by sWitching the valve to a large opening state soon after the compressor is stopped, it is possible to hold the cooled or heated refrigerant inside the radiation panel for a longer time, and thus it is possible to cool or heat the indoor air for a longer time. Thus, in therrnostat ON/OFF control (control Where the compressor is stopped When the surface temperature of the radiation panel has reached a target temperature, and the compressor is restarted When the surface temperature of the radiation panel leaves the target temperature), a period of time between stop and restart of the compressor becomes long, Which contributes to saving energy. Moreover, also in cases Where the cooling or heating operation is stopped by a timer and Where the user stops the cooling or heating operation by using a remote controller or the like, the cooling or heating effect can be maintained thereafter _ 14 _ for a While.

[0042] Compared With indoor heat exchangers of general separate-type air conditioners that circulate indoor air by means of an indoor blower, radiation panels are quite large in size (for example, some are almost twice as large in volume, and some are even so large that they occupy one Whole ceiling or one Whole Wall). With this being the case, by performing the control according to the present invention, it is possible to make effective use of energy.

[0043] As for timing of stopping the compressor 12 and timing of switching the expansion valve 15 and the electromagnetic valve 25 to the small opening state, the compressor 12 may be stopped first, or the expansion valve 15 and the electromagnetic valve 25 may be sWitched to the small opening state ﬁrst. Or, the stopping of the compressor 12 and the switching of the expansion valve 15 and the electromagnetic valve 25 may take place simultaneously. Stopping of the compressor 12 before switching of the expansion valve 15 and the electromagnetic valve 25 to the small opening state is advantageous in that shock caused When the expansion valve 15 and the electromagnetic valve 25 are switched to the small opening state can be reduced, but disadvantageous in that the reﬁigerant keeps moving until the expansion valve 15 and the electromagnetic valve 25 are sWitched to the small opening state. SWitching the expansion valve 15 and the electromagnetic valve 25 to the small opening state before stopping the compressor 12 is advantageous in that it can immediately be made difficult for the refrigerant to move, but disadvantageous in that a shock is caused in the refrigeration cycle. Thus, the timing should preferably be chosen considering strength of the components of the refrigeration cycle.

[0044] In restarting the compressor 12 in a stopped state, the expansion valve 15 and the electromagnetic valve 25 are preferably sWitched to the large opening state in advance. _ 15 _ This is for the purpose of preventing pressure difference from arising at the time of restarting the compressor 12 to thereby allow a smooth restart. In the small opening state (for example, in a case where the opening state of the valves is classified into 0 (fully closed) to 512 (fully open) stages, opening of around 1 to 10 states), pressure balance is gradually achieved between high-pressure and low-pressure sides. As a result, the pressure difference between the low-pressure and high-pressure sides when the valves are ﬁally opened before the compressor 12 is restarted is smaller than when the valves are fully opened aﬁer being kept fully closed until just before the compressor 12 is restarted. This brings about an advantageous effect where refrigerant noise is hard to be caused when the valves are ﬁally opened before the compressor 12 is restarted. Note that an adequate small opening state may preferably be deterrnined through experiments. Note also that, as long as the pressure balance is achieved before the compressor 12 is restarted, the timing of achieving the pressure balance does not have to be immediately before the compressor 12 is restarted.

[0045] Instead of using the electromagnetic valve 25 whose opening is variable as described above, an electromagnetic valve whose opening is variable between only two stages, that is, a fully closed state as the small opening state and a fully opened state as the large opening state could be used. Or, an additional electromagnetic valve may be provided between the expansion valve 15 and the two-way valve 19 such that the additional electromagnetic valve is switched to the small opening state.

[0046] In the present embodiment, the expansion valve 15 is used not only for its original purpose but also for the purpose of making it difficult for the refrigerant to move.

By assigning the expansion valve 15 the two roles in this way, it is possible to achieve a simple configuration. The configuration, however, may be such that an electromagnetic valve like the electromagnetic valve 25 is arranged on the expansion valve 15 side. _ 16 _

[0047] Furthermore, in the present embodiment, With the electromagnetic valve 25 provided in addition to the expansion valve 15, the configuration is such that a valve is arranged one in each of the refrigerant pipes on the refrigerant inlet and outlet sides With respect to the radiation panel 30. However, it is also possible to omit the electromagnetic valve 25 and assign only the expansion valve 15 the role of making it difficult for the refrigerant to move.

[0048] The discussion hitherto has been based on that the radiators 32 are vertically arranged, but a configuration is possible Where the radiators 32 are horizontally arranged. In that case, the radiation fin 34 is preferably configured such that a large number of thin plates perpendicular to the axial line of the refrigerant pipe 33 are arranged at intervals therebetWeen.

[0049] The foregoing has described the embodiments of the present invention. The present invention, however, is not limited in scope thereto and can be implemented in variously modified forms Within the spirit of the invention.

Industrial Applicability [005 0] The present invention is Widely applicable in radiation-type air conditioners.

List of Reference Signs [005 1] 1 radiation-type air conditioner 10 outdoor unit 11 housing 12 compressor 13 four-Way valve 14 15 16 _ 17 _ outdoor heat exchanger expansion valve outdoor bloWer 17, 18 refrigerant pipe 25 30 31 32 36 40 electromagnetic valve radiation panel housing radiator therrnometric device controller

Claims

_18- CLAIMS

1. Claim 1 A radiation-type air Conditioner, comprising: a radiation panel placed indoors; an outdoor heat exchanger; a Compressor that circulates a refrigerant in the radiation panel and the outdoor heat exchanger via a refrigerant pipe; a controller; and a valve arranged in the refrigerant pipe connected to the radiation panel, Wherein While stopping the compressor in operation, the controller brings the valve into a small opening state.

2. Claim 2 The radiation-type air conditioner of claim l, Wherein each of an inlet side and an outlet side of the radiation panel is provided With the refrigerant pipe, and the valve is disposed at each of the refrigerant pipes on the inlet and outlet sides of the radiation panel.

3. Claim 3 The radiation-type air conditioner of claim l, Wherein the valve is an _19- expansion valve.

4. Claim 4 The radiation-type air Conditioner of claim 2, Wherein the valve is an expansion valve.

5. Claim 5 The radiation-type air conditioner of any one of claims l to 4, Wherein the small opening state includes a ﬁally closed state.