JP2019143966A - Air-conditioning apparatus - Google Patents

Abstract

To inhibit growth of ice on a surface of a radiant heat exchanger during cooling operation of an air-conditioning apparatus.SOLUTION: An air-conditioning apparatus performs cooling operation in which a radiant heat exchanger functions as an evaporator. During the cooling operation, a radiation controller for a radiation panel determines whether a first starting condition is met. The first starting condition is that the integrated duration of a first low-temperature state is equal to or greater than a first starting reference time, where the first low-temperature state is at or below a first starting reference temperature being at most 0°C according to a measurement of a liquid-side temperature sensor of the radiation panel. If the first starting condition is met, the radiation controller outputs a start defrost signal to an outdoor controller of an outdoor unit, and the outdoor controller starts defrost operation and stops a compressor.SELECTED DRAWING: Figure 3

Description

  The present disclosure relates to an air conditioner.

  Patent Document 1 discloses an air conditioner including a radiant heat exchanger (see FIG. 6). This air conditioner includes a refrigerant circuit in which a plurality of radiant heat exchangers are connected to an outdoor unit that is a heat source unit. This air conditioner performs a cooling operation in which the radiant heat exchanger functions as an evaporator.

Japanese Utility Model Publication 2-114484

  If the temperature of the radiant heat exchanger becomes lower than 0 ° C. during the cooling operation, moisture in the air may condense on the surface of the radiant heat exchanger and further freeze. In this case, if the cooling operation is continued as it is, the ice attached to the surface of the radiant heat exchanger will grow. And if the quantity of ice adhering to the surface of a radiant heat exchanger increases, there exists a possibility of causing the fall of the heat exchange capability of a radiant heat exchanger. In addition, the ice adhering to the radiant heat exchanger melts after the cooling operation is stopped, but if the amount of ice adhering to the surface of the radiant heat exchanger is large, a part of the ice may fall off the radiant heat exchanger as it is. . However, until now, no measures have been taken to suppress the growth of ice adhering to the surface of the radiant heat exchanger during cooling operation.

  An object of the present disclosure is to suppress the growth of ice on the surface of the radiant heat exchanger during the cooling operation of the air conditioner.

  In the first aspect of the present disclosure, a radiant air conditioning unit (40) having a radiant heat exchanger (52) is connected to a heat source unit (20) having a compressor (21) via a communication pipe (16, 17). An air conditioner that includes a refrigerant circuit (11) and performs at least a cooling operation in which the radiant heat exchanger (52) functions as an evaporator is a target. The radiant air conditioning unit (40) includes a liquid pipe (53) for introducing a refrigerant into the radiant heat exchanger (52) during the cooling operation, and a liquid side temperature for measuring the temperature of the liquid pipe (53). A controller (90) provided with a sensor (65) and configured to perform a melting operation to keep the compressor (21) stopped when a predetermined first start condition is established during the cooling operation. And the first start condition is the duration of the first low temperature state in which the measured value of the liquid temperature sensor (65) is not higher than the first start reference temperature of 0 ° C. or lower, or the duration of the first low temperature state. This is a condition that the integrated value becomes equal to or longer than the first start reference time.

  In the controller (90) of the first aspect, the duration of the first low temperature state (state where the measured value of the liquid side temperature sensor (65) is equal to or lower than the first start reference temperature) is equal to or longer than the first start reference time. Or when the integrated value of the duration of the first low temperature state is equal to or greater than the first start reference time, the melting operation for stopping the compressor (21) is started. The first starting reference temperature is 0 ° C. or lower.

  In the first aspect, when the controller (90) starts the melting operation and stops the compressor (21), the flow of the refrigerant into the radiant heat exchanger (52) stops, and the radiant heat exchanger (52) The surface temperature rises. And if the surface temperature of a radiant heat exchanger (52) exceeds 0 degreeC, the ice adhering to the surface of a radiant heat exchanger (52) will melt. Therefore, when the controller (90) performs the melting operation when the first start condition is satisfied, the ice attached to the surface of the radiant heat exchanger (52) during the cooling operation melts before it grows and becomes large. . Therefore, according to this aspect, it is possible to suppress the growth of ice attached to the surface of the radiant heat exchanger (52) during the cooling operation.

  According to a second aspect of the present disclosure, in the first aspect, when the controller (90) satisfies at least one of the first start condition and a predetermined second start condition during the cooling operation, The second start condition is a second low temperature state in which the measured value of the liquid side temperature sensor (65) is equal to or lower than a second start reference temperature lower than the first start reference temperature. Or the integrated value of the duration of the second low temperature state is equal to or longer than the second start reference time shorter than the first start reference time.

  The controller (90) of the second aspect starts the melting operation not only when the first start condition is satisfied during the cooling operation but also when the second start condition is satisfied during the cooling operation. That is, in this aspect, when the duration of the second low temperature state (state where the measured value of the liquid side temperature sensor (65) is equal to or lower than the second start reference temperature) becomes equal to or longer than the second start reference time, or the second When the integrated value of the continuation time in the low temperature state is equal to or longer than the second start reference time, the controller (90) starts the melting operation. The second start reference temperature is lower than the first start reference temperature, and the second start reference time is shorter than the first start reference time. Therefore, according to this aspect, it is possible to more reliably suppress the growth of ice attached to the surface of the radiant heat exchanger (52).

  According to a third aspect of the present disclosure, in the first or second aspect, the controller (90) operates the compressor (21) when a predetermined first end condition is satisfied during the melting operation. And the cooling operation is restarted, and the first end condition is a first temperature rise state in which the measured value of the liquid side temperature sensor (65) is equal to or higher than a first end reference temperature higher than 0 ° C. Or the integrated value of the duration of the first temperature rising state is equal to or longer than the first end reference time.

  The controller (90) of the third aspect is configured such that the duration of the first temperature rise state (state where the measured value of the liquid side temperature sensor (65) is equal to or higher than the first end reference temperature) is equal to or longer than the first end reference time. When it becomes, or when the integrated value of the duration of the first temperature rise state becomes equal to or longer than the first end reference time, the melting operation is ended and the cooling operation is restarted. The first end reference temperature is higher than 0 ° C. Therefore, according to this aspect, it is possible to terminate the melting operation at an appropriate timing and restart the cooling operation, and it is possible to suppress a decrease in comfort due to the melting operation.

  According to a fourth aspect of the present disclosure, in the third aspect, when the controller (90) satisfies at least one of the first end condition and the predetermined second end condition during the melting operation, The compressor (21) is operated to restart the cooling operation, and the second end condition is that the measured value of the liquid side temperature sensor (65) is higher than the first end reference temperature. 2. The condition that the duration of the second temperature rise state that is equal to or higher than the 2 end reference temperature or the integrated value of the duration of the second temperature rise state is equal to or longer than the second end reference time that is shorter than the first end reference time. It is what is.

  The controller (90) of the fourth aspect terminates the melting operation not only when the first end condition is satisfied during the melting operation but also when the second end condition is satisfied during the melting operation. Resume operation. That is, in this aspect, when the duration of the second temperature rise state (state where the measured value of the liquid temperature sensor (65) is equal to or higher than the second end reference temperature) becomes equal to or longer than the second end reference time, (2) When the integrated value of the duration time of the temperature rise state becomes equal to or longer than the second end reference time, the controller (90) operates the compressor (21) to restart the cooling operation. The second end reference temperature is higher than the first end reference temperature, and the second end reference time is shorter than the first end reference time. Therefore, according to this aspect, it is possible to reduce the possibility of continuing the melting operation despite the fact that all of the ice adhering to the surface of the radiant heat exchanger (52) is melting, resulting from the melting operation. A decrease in comfort can be reliably suppressed.

  According to a fifth aspect of the present disclosure, in the fourth aspect, the controller (90) includes at least one of the first end condition, the second end condition, and the predetermined third end condition during the melting operation. When one of them is established, the compressor (21) is operated to restart the cooling operation. The third end condition is that the liquid side temperature sensor (65) is measured from the start of the melting operation. The time until the value reaches the second end reference temperature is equal to or shorter than a predetermined determination reference time, and the measured value of the liquid side temperature sensor (65) is equal to or higher than the second end reference temperature. Is a condition that the third end reference time is shorter than the second end reference time.

  The controller (90) of the fifth aspect is not limited to the case where the first end condition is satisfied during the melting operation and the case where the second end condition is satisfied during the melting operation, but also the third end condition during the melting operation. Even when is established, the melting operation is terminated and the cooling operation is resumed. That is, the controller (90) of this aspect is configured so that the time until the measured value of the liquid side temperature sensor (65) reaches the second end reference temperature is equal to or shorter than a predetermined determination reference time, and the liquid side temperature sensor ( When the duration of the state in which the measured value of 65) is equal to or higher than the second end reference temperature is equal to or longer than the third end reference time, the compressor (21) is operated to restart the cooling operation. The third end reference time is shorter than the second end reference time. Therefore, according to this aspect, it is possible to reduce the possibility of continuing the melting operation despite the fact that all of the ice adhering to the surface of the radiant heat exchanger (52) is melting, resulting from the melting operation. A decrease in comfort can be reliably suppressed.

FIG. 1 is a piping diagram illustrating a schematic configuration of the air-conditioning apparatus according to the first embodiment. FIG. 2 is a front view illustrating a schematic configuration of the radiation panel according to the first embodiment. FIG. 3 is a state transition diagram illustrating an operation performed by the control system of the first embodiment.

  An air conditioner (10) of an embodiment will be described with reference to the drawings.

-Overall configuration of air conditioner-
The air conditioner (10) performs indoor air conditioning. As shown in FIG. 1, the air conditioner (10) includes an outdoor unit (20), an indoor unit (30), and a radiation panel (40). The numbers of the outdoor unit (20), the indoor unit (30), and the radiation panel (40) shown in FIG. 1 are merely examples.

  The outdoor unit (20) is installed outdoors. The outdoor unit (20) constitutes a heat source unit. The outdoor unit (20) is provided with an outdoor circuit (12) and an outdoor controller (C3), which will be described later, and an outdoor fan (25).

  The indoor unit (30) is provided near the ceiling of the room. The indoor unit (30) constitutes a convection type indoor unit that performs cooling or heating by air conveyed by the indoor fan (33). The number of indoor units (30) is one or more. The indoor unit (30) is provided with an indoor circuit (13) and an indoor controller (C1), which will be described later, and an indoor fan (33).

  The radiant panel (40) is installed on the indoor floor. A radiation panel (40) comprises the radiation air-conditioning unit which cools or heats by the movement of radiant heat. The number of radiation panels (40) is one or more. The radiation panel (40) is provided with a radiation circuit (15) and a radiation controller (C2) which will be described later.

  The air conditioner (10) includes a refrigerant circuit (11) through which the filled refrigerant circulates. Details of the refrigerant circuit (11) will be described later.

-Overall configuration of radiation panel-
The overall configuration of the radiation panel (40) will be described with reference to FIG. The radiation panel (40) includes a pair of support columns (41), a panel body (52) (also referred to as a radiation heat exchanger (52)), and a bottom plate (42).

  One support (41) is provided at each of the left and right ends of the radiation panel (40). Each column (41) is erected on the floor surface and extends in the vertical direction.

  The panel body (52) is provided between the pair of support posts (41). The front surface and the rear surface of the panel body (52) are exposed to the indoor space.

  The bottom plate (42) extends left and right between the pair of support columns (41) so as to be connected to the lower ends of the pair of support columns (41). The bottom plate (42) is fixed to the floor surface in the room via a fastening member (not shown) such as an anchor bolt. The upper ends of the pair of support columns (41) are connected to a ceiling-side suspension bolt (not shown) via the fixing portion (43).

  In the radiation panel (40), a lower housing chamber (44) is formed below the panel body (52). The lower storage chamber (44) is provided with a drain pan (45) for collecting condensed water generated from the panel body (52). The open surfaces on the front side and the rear side of the lower storage chamber (44) are respectively covered with the lower cover (46). Each lower cover (46) is detachably attached to, for example, the lower portion of the pair of support posts (41).

  In the radiation panel (40), an upper accommodation chamber (47) is formed above the panel body (52). The upper accommodation chamber (47) accommodates a liquid pipe (53) and a gas pipe (54) of a radiation circuit (15) to be described later. The liquid pipe (53) is provided with a radiation expansion valve (51) (not shown in FIG. 2). Although not shown in FIG. 2, a radiation controller (C2) is disposed in the upper storage chamber (47). The open surfaces on the front side and the rear side of the upper storage chamber (47) are respectively covered with the upper cover (48). Each upper cover (48) is detachably attached to, for example, upper portions of a pair of support columns (41).

-Configuration of refrigerant circuit-
The configuration of the refrigerant circuit (11) will be described in detail with reference to FIG. The refrigerant circuit (11) includes an outdoor circuit (12), an indoor circuit (13), and a radiation circuit (15).

  In the present embodiment, the indoor unit (30) and the radiation panel (40) are connected to the outdoor unit (20) via the two connecting pipes (16, 17). Strictly speaking, the indoor circuit (13) and the radiation circuit (15) are connected to the outdoor circuit (12) via a gas communication pipe (16) and a liquid communication pipe (17) as communication pipes.

<Outdoor circuit>
The outdoor circuit (12) is provided with a compressor (21), an outdoor heat exchanger (22), an outdoor expansion valve (23), and a four-way switching valve (24). The compressor (21) is configured as a variable capacity type. More specifically, the refrigerant circulation amount of the refrigerant circuit (11) can be adjusted by controlling the operating frequency of the compressor (21) by the inverter device. In the vicinity of the outdoor heat exchanger (22), an outdoor fan (25) for conveying outdoor air is provided. In the outdoor heat exchanger (22), heat is exchanged between the refrigerant flowing inside the outdoor air and the outdoor air conveyed by the outdoor fan (25). The outdoor expansion valve (23) is a flow rate control valve whose opening degree is variable, and is constituted by, for example, an electronic expansion valve.

  The four-way switching valve (24) constitutes a switching mechanism for switching between heating operation and cooling operation. Specifically, the four-way selector valve (24) is configured to be switchable between a first state (state indicated by a solid line in FIG. 1) and a second state (state indicated by a broken line in FIG. 1). The four-way switching valve (24) switches to the first state in the cooling operation. The four-way switching valve (24) in the first state communicates the discharge side of the compressor (21) with the gas end of the outdoor heat exchanger (22), and at the same time communicates gas with the suction side of the compressor (21). Connect the pipe (16). The four-way selector valve (24) switches to the second state in the heating operation. The four-way switching valve (24) in the second state allows the discharge side of the compressor (21) and the gas communication pipe (16) to communicate with each other, and at the same time, the suction side of the compressor (21) and the outdoor heat exchanger (22). The gas end is communicated with.

  The outdoor circuit (12) is provided with a discharge pressure sensor (61) and a suction pressure sensor (62). The discharge pressure sensor (61) is provided on the discharge side of the compressor (21). The discharge pressure sensor (61) detects the pressure of refrigerant discharged from the compressor (21) (high pressure of the refrigeration cycle). The suction pressure sensor (62) detects the pressure of refrigerant sucked by the compressor (21) (low pressure of the refrigeration cycle).

<Indoor circuit>
The indoor circuit (13) includes an indoor heat exchanger (31), an indoor expansion valve (32), a liquid pipe (34), and a gas pipe (35). The indoor heat exchanger (31) has one end of the liquid pipe (34) connected to the liquid side end thereof, and one end of the gas pipe (35) connected to the gas side end thereof. The other end of the liquid pipe (34) is connected to the liquid communication pipe (17). The other end of the gas pipe (35) is connected to the gas communication pipe (16). The indoor expansion valve (32) is disposed in the middle of the liquid pipe (34).

  The indoor expansion valve (32) is a flow rate control valve having a variable opening, and is constituted by, for example, an electronic expansion valve. In the vicinity of the indoor heat exchanger (31), an indoor fan (33) that conveys indoor air is provided. In the indoor heat exchanger (31), heat is exchanged between the refrigerant flowing through the indoor heat exchanger (31) and the indoor air conveyed by the indoor fan (33).

  The indoor circuit (13) is provided with a first liquid side temperature sensor (63) and a first gas side temperature sensor (64). A 1st liquid side temperature sensor (63) is provided in the part which connects an indoor expansion valve (32) and an indoor heat exchanger (31) among liquid pipes (34), and detects the temperature of a liquid pipe (34). The first gas side temperature sensor (64) is provided in the gas pipe (35) and detects the temperature of the gas pipe (35).

<Radiation circuit>
The radiation circuit (15) includes a radiation heat exchanger (52), a radiation expansion valve (51), a liquid pipe (53), and a gas pipe (54). The radiant heat exchanger (52) has one end of a liquid pipe (53) connected to its liquid side end, and one end of a gas pipe (54) connected to its gas side end. The other end of the liquid pipe (53) is connected to the liquid communication pipe (17). The other end of the gas pipe (54) is connected to the gas communication pipe (16). The radiation expansion valve (51) is disposed in the middle of the liquid pipe (53).

  The radiation expansion valve (51) is a flow rate adjustment valve whose opening degree is variable, and is constituted by, for example, an electronic expansion valve. In the vicinity of the radiant heat exchanger (52), no fan for conveying air is provided. That is, the radiant heat exchanger (52) exchanges heat between the refrigerant and the room air by the movement of the radiant heat.

  The radiation circuit (15) is provided with a second liquid side temperature sensor (65) and a second gas side temperature sensor (66). A 2nd liquid side temperature sensor (65) is provided in the part which connects a radiation expansion valve (51) and a radiant heat exchanger (52) among liquid pipes (53), and detects the temperature of a liquid pipe (53). The second gas side temperature sensor (66) is provided in the gas pipe (54) and detects the temperature of the gas pipe (54).

-Control system-
In the air conditioner (10) of this embodiment, the outdoor controller (C3) of the outdoor unit (20), the indoor controller (C1) of each indoor unit (30), and the radiation controller (C2) of each radiation panel (40) Are connected to each other by wiring to form a control system (90). The control system (90) is a controller that controls the operation of the air conditioner (10).

  Although not shown, each of the outdoor controller (C3), the indoor controller (C1), and the radiation controller (C2) stores a CPU that executes a control program, a control program, data necessary for executing the control program, and the like. And a memory.

<Outdoor controller>
The outdoor controller (C3) receives the measurement values of the discharge pressure sensor (61) and the suction pressure sensor (62) and the measurement values of other sensors provided in the outdoor unit (20). The outdoor controller (C3) adjusts the operating capacity of the compressor (21), the rotational speed of the outdoor fan (25), the opening of the outdoor expansion valve (23), etc., and operates the four-way switching valve (24). Configured to do.

  The outdoor controller (C3) receives a melting start signal and a melting end signal described later from the indoor controller (C1) and the radiation controller (C2). The outdoor controller (C3) is configured to stop the compressor (21) when receiving the melting start signal and to operate the compressor (21) when receiving the melting end signal.

<Indoor controller>
The indoor controller (C1) includes the measured values of the first liquid side temperature sensor (63) and the first gas side temperature sensor (64) provided in the same indoor unit (30), and the indoor unit (30). Measurement values of other sensors provided are input. The indoor controller (C1) adjusts the opening degree of the indoor expansion valve (32) and the rotational speed of the indoor fan (33) provided in the same indoor unit (30) based on the input measurement values.

  The indoor controller (C1) is configured to determine success or failure of the first start condition and the second start condition during the cooling operation of the air conditioner (10). The indoor controller (C1) is configured to output a melting start signal to the outdoor controller (C3) when at least one of the first start condition and the second start condition is satisfied. The operations of these indoor controllers (C1) are the same as the operations of the radiation controller (C2) described later.

  In addition, the indoor controller (C1) is configured to determine whether the first end condition, the second end condition, and the third end condition are successful during the melting operation described later. The indoor controller (C1) is configured to output a melting end signal to the outdoor controller (C3) when at least one of the first end condition, the second end condition, and the third end condition is satisfied. The operations of these indoor controllers (C1) are the same as the operations of the radiation controller (C2) described later.

<Radiation controller>
In the radiation controller (C2), the measured values of the second liquid side temperature sensor (65) and the second gas side temperature sensor (66) provided in the same radiation panel (40) and the radiation panel (40) Measurement values of other sensors provided are input. A radiation controller (C2) adjusts the opening degree of the radiation expansion valve (51) provided in the same radiation panel (40) based on the input measured value.

  The radiation controller (C2) is configured to determine success or failure of the first start condition and the second start condition during the cooling operation of the air conditioner (10). The first start condition and the second start condition are conditions for starting a melting operation described later. The first start condition and the second start condition will be described later. The radiation controller (C2) is configured to output a melting start signal to the outdoor controller (C3) when at least one of the first start condition and the second start condition is satisfied.

  Further, the radiation controller (C2) is configured to determine whether the first end condition, the second end condition, and the third end condition are successful during the melting operation described later. The first end condition, the second end condition, and the third end condition are conditions for ending the melting operation described later. The first end condition, the second end condition, and the third end condition will be described later. The radiation controller (C2) is configured to output a melting end signal to the outdoor controller (C3) when at least one of the first end condition, the second end condition, and the third end condition is satisfied.

-Operation of air conditioner-
The operation of the air conditioner (10) will be described with reference to FIG. The air conditioner (10) switches between a cooling operation and a heating operation.

<Cooling operation>
In the cooling operation, the four-way switching valve (24) is in the first state (the state indicated by the solid line in FIG. 1), the outdoor expansion valve (23) is kept fully open, the indoor expansion valve (32) and the radiation expansion valve (51 ) Is adjusted. In the refrigerant circuit (11), a vapor compression refrigeration cycle is performed, the outdoor heat exchanger (22) functions as a condenser, and the indoor heat exchanger (31) and the radiant heat exchanger (52) function as an evaporator. To do.

  Specifically, the refrigerant discharged from the compressor (21) flows into the outdoor heat exchanger (22) and condenses after passing through the four-way switching valve (24). Thereafter, the refrigerant flows through the outdoor expansion valve (23) and then flows into the liquid communication pipe (17) and is distributed to the indoor circuit (13) and the radiation circuit (15).

  The refrigerant flowing into the indoor circuit (13) from the liquid communication pipe (17) flows through the liquid pipe (34) and expands when passing through the indoor expansion valve (32), and then to the indoor heat exchanger (31). It flows and evaporates. The indoor unit (30) blows out the cooled air into the room. The refrigerant flowing out from the indoor heat exchanger (31) flows into the gas communication pipe (16) through the gas pipe (35).

  On the other hand, the refrigerant flowing into the radiation circuit (15) from the liquid communication pipe (17) flows through the liquid pipe (53) and expands when passing through the radiation expansion valve (51), and then the radiation heat exchanger (52). Evaporates and evaporates. In the radiant panel (40), the surface temperature of the radiant heat exchanger (52) is lowered, and the radiant heat exchanger (52) absorbs heat from the occupants and furniture by radiation. The refrigerant flowing out from the radiant heat exchanger (52) flows into the gas communication pipe (16) through the gas pipe (54).

  The refrigerant that has flowed into the gas communication pipe (16) from the indoor circuit (13) and the radiation circuit (15) flows into the outdoor circuit (12) and is sucked into the compressor (21) after passing through the four-way selector valve (24). The The compressor (21) compresses the sucked refrigerant and discharges it.

<Heating operation>
In the heating operation, the four-way switching valve (24) is in the second state (the state indicated by the broken line in FIG. 1), and the opening degrees of the outdoor expansion valve (23), the indoor expansion valve (32), and the radiation expansion valve (51) are Adjusted. In the refrigerant circuit (11), a vapor compression refrigeration cycle is performed, the indoor heat exchanger (31) and the radiant heat exchanger (52) function as a condenser, and the outdoor heat exchanger (22) functions as an evaporator. To do.

  Specifically, the refrigerant discharged from the compressor (21) flows into the gas communication pipe (16) after passing through the four-way switching valve (24), and then distributed to the indoor circuit (13) and the radiation circuit (15). Is done.

  The refrigerant flowing into the indoor circuit (13) from the gas communication pipe (16) flows into the indoor heat exchanger (31) through the gas pipe (35) and condenses. The indoor unit (30) blows out heated air into the room. The refrigerant flowing out of the indoor heat exchanger (31) flows through the liquid pipe (34), passes through the indoor expansion valve (32), and then flows into the liquid communication pipe (17).

  The refrigerant flowing into the radiation circuit (15) from the gas communication pipe (16) flows into the radiation heat exchanger (52) through the gas pipe (54) and condenses. In the radiant panel (40), the surface temperature of the radiant heat exchanger (52) becomes high, and the radiant heat exchanger (52) radiates heat to occupants and furniture by radiation. The refrigerant that has flowed out of the radiant heat exchanger (52) flows through the liquid pipe (53), passes through the radiant expansion valve (51), and then flows into the liquid communication pipe (17).

  The refrigerant flowing into the liquid communication pipe (17) from the indoor circuit (13) and the radiation circuit (15) flows into the outdoor circuit (12) and passes through the outdoor expansion valve (23), and then the outdoor heat exchanger ( To 22) and evaporate. Thereafter, the refrigerant is sucked into the compressor (21) after passing through the four-way switching valve (24). The compressor (21) compresses the sucked refrigerant and discharges it.

-Control system operation-
The control system (90) performs an operation for controlling the operation of the air conditioner (10). As one of the operations, the control system (90) performs a melting operation. This melting operation is performed in order to melt the ice adhering to the indoor heat exchanger (31) of the indoor unit (30) or the radiant heat exchanger (52) of the radiant panel (40) during the cooling operation. ) In a stopped state.

  As shown in FIG. 3, when a predetermined condition is established during the cooling operation, the control system (90) pauses the cooling operation and executes the melting operation. When the predetermined condition is established during the melting operation, the control system (90) To finish cooling operation. Here, the operation of the control system (90) will be described in detail.

<Start of melting operation>
The indoor controller (C1) and the radiation controller (C2) determine whether the first start condition and the second start condition are successful during the cooling operation. The first start condition and the second start condition are conditions for starting the melting operation.

  The first start condition is that the integrated value of the duration of the “first low temperature state where the temperature TL of the liquid pipe (34, 53) is equal to or lower than the first start reference temperature T_in1 (TL ≦ T_in1)” is the first start reference time. The condition is that M_in1 or more. The first start reference temperature T_in1 is 0 ° C. or lower (T_in1 ≦ 0 ° C.).

  The second start condition is that the integrated value of the duration of the “second low temperature state where the temperature TL of the liquid pipe (34, 53) is equal to or lower than the second start reference temperature T_in2 (TL ≦ T_in2)” is the second start reference time. The condition is that M_in2 or more. The second start reference temperature T_in2 is lower than the first start reference temperature T_in1 (T_in2 <T_in1). Further, the second start reference time M_in2 is shorter than the first start reference time M_in1 (M_in2 <M_in1).

  The temperature of the liquid pipe (34) of the indoor circuit (13) is measured by the first liquid side temperature sensor (63). Therefore, the indoor controller (C1) uses the measurement value of the first liquid side temperature sensor (63) as the temperature TL of the liquid pipe (34) to determine whether the first start condition and the second start condition are successful. The indoor controller (C1) transmits a melting start signal to the outdoor controller (C3) when at least one of the first start condition and the second start condition is satisfied.

  The temperature of the liquid pipe (53) of the radiation circuit (15) is measured by the second liquid side temperature sensor (65). Therefore, the radiation controller (C2) uses the measured value of the second liquid side temperature sensor (65) as the temperature TL of the liquid pipe (53) to determine whether the first start condition and the second start condition are successful. The radiation controller (C2) transmits a melting start signal to the outdoor controller (C3) when at least one of the first start condition and the second start condition is satisfied.

  When the outdoor controller (C3) receives a melting start signal from at least one of the indoor controller (C1) and the radiation controller (C2) constituting the control system (90), the outdoor controller (C3) starts the melting operation and turns on the compressor (21). Stop. While the compressor (21) is stopped, the refrigerant does not circulate in the refrigerant circuit (11). That is, the refrigeration cycle in the refrigerant circuit (11) is stopped while the compressor (21) is stopped. While the refrigeration cycle is stopped, the temperatures of the indoor heat exchanger (31) and the radiant heat exchanger (52) gradually increase. As a result, the ice adhering to the indoor heat exchanger (31) or the radiant heat exchanger (52) gradually melts.

  Here, the reason why the radiation controller (C2) outputs the melting start signal when at least one of the first start condition and the second start condition is satisfied will be described. The reason why the indoor controller (C1) outputs the melting start signal when at least one of the first start condition and the second start condition is satisfied is the same as this.

  The refrigerant that has flowed into the radiant panel (40) during the cooling operation flows into the radiant heat exchanger (52) through the liquid pipe (53). For this reason, during the cooling operation, the lower the temperature of the liquid pipe (53), the lower the temperature of the radiant heat exchanger (52). When the surface temperature of the radiant heat exchanger (52) becomes 0 ° C. or less over a certain period of time, moisture in the air becomes ice (or frost) and adheres to the surface of the radiant heat exchanger (52).

  On the other hand, when the integrated value of the duration of the “first low temperature state where the measured value of the second liquid side temperature sensor (65) is equal to or less than the first start reference temperature T_in1” reaches the first start reference time M_in1 or more ( That is, when the first start condition is satisfied), the surface temperature of the radiant heat exchanger (52) has become 0 ° C. or less over a certain period of time, and the water adhering to the surface of the radiant heat exchanger (52) The amount is likely to reach a certain level. Therefore, when the first start condition is satisfied, the radiation controller (C2) transmits a melting start signal to the outdoor controller (C3).

  Further, when the measured value of the second liquid side temperature sensor (65) becomes lower than the first start reference temperature T_in1 over a certain period of time, the first low temperature state (measurement of the second liquid side temperature sensor (65)). The amount of water adhering to the surface of the radiant heat exchanger (52) is to some extent even before the integrated value of the duration of the state in which the value is equal to or less than the first start reference temperature T_in1) before the first start reference time M_in1 May reach above.

  On the other hand, when the integrated value of the duration of the “second low temperature state in which the measurement value of the second liquid side temperature sensor (65) is equal to or lower than the second start reference temperature T_in2” reaches the second start reference time M_in2 or more ( That is, when the second start condition is satisfied), the surface temperature of the radiant heat exchanger (52) is lower than the first start reference temperature T_in1 over a certain period of time, and the duration of the first low temperature state is Even before the integrated value reaches the first start reference time M_in1, there is a high possibility that the amount of water adhering to the surface of the radiant heat exchanger (52) has reached a certain level. Therefore, even if the first start condition is not satisfied, the radiation controller (C2) transmits a melting start signal to the outdoor controller (C3) when the second start condition is satisfied.

<End of melting operation>
The indoor controller (C1) and the radiation controller (C2) determine whether the first end condition, the second end condition, and the third end condition are successful during the execution of the melting operation. The first end condition, the second end condition, and the third end condition are conditions for ending the melting operation.

  The first end condition is that the duration of the “first temperature rise state in which the temperature TL of the liquid pipe (34, 53) is equal to or higher than the first end reference temperature T_out1 (TL ≧ T_out1)” (that is, the first rise continuously) This is a condition that the time during which the temperature is reached is equal to or longer than the first end reference time M_out1. The first end reference temperature T_out1 is higher than 0 ° C. (0 ° C. <T_out1).

  The second end condition is the duration of the “second temperature rise state in which the temperature TL of the liquid pipe (34, 53) is equal to or higher than the second end reference temperature T_out2 (TL ≧ T_out2)” (that is, the second rise continuously) This is a condition that the time during which the temperature is reached is equal to or longer than the second end reference time M_out2. The second end reference temperature T_out2 is higher than the first end reference temperature T_out1 (T_out2> T_out1). The second end reference time M_out2 is shorter than the first end reference time M_out1 (M_out2 <M_out1).

  The third end condition is that the time MR from the start of the melting operation until the temperature TL of the liquid pipe (34, 53) reaches the second end reference temperature T_out2 is equal to or less than a predetermined determination reference time MJ (MR ≦ MJ), In addition, the condition that the duration of the “second temperature rise state in which the temperature TL of the liquid pipe (34, 53) is equal to or higher than the second end reference temperature T_out2 (TL ≧ T_out2)” is equal to or longer than the third end reference time M_out3. It is. The third end reference time M_out3 is shorter than the second end reference time M_out2 (M_out3 <M_out2).

  The indoor controller (C1) uses the measured value of the first liquid side temperature sensor (63) as the temperature TL of the liquid pipe (34) to determine whether the first end condition, the second end condition, and the third end condition are successful. to decide. The indoor controller (C1) transmits a melting end signal to the outdoor controller (C3) when at least one of the first start condition, the second start condition, and the third end condition is satisfied.

  The radiation controller (C2) uses the measured value of the second liquid side temperature sensor (65) as the temperature TL of the liquid pipe (34) to determine whether the first end condition, the second end condition, and the third end condition are successful. to decide. When at least one of the first start condition, the second start condition, and the third end condition is satisfied, the radiation controller (C2) transmits a melting end signal to the outdoor controller (C3).

  When the outdoor controller (C3) receives a melting end signal from at least one of the indoor controller (C1) and the radiation controller (C2) constituting the control system (90), the outdoor controller (C3) ends the melting operation and turns the compressor (21) on. Start and resume cooling operation.

  Here, the reason why the radiation controller (C2) outputs the melting end signal when at least one of the first start condition, the second start condition, and the third end condition is satisfied will be described. The reason why the indoor controller (C1) outputs the melting end signal when at least one of the first start condition, the second start condition, and the third end condition is satisfied is the same as this.

  When the measured value of the second liquid side temperature sensor (65) is higher than 0 ° C. over a certain period of time, the surface temperature of the radiant heat exchanger (52) exceeds 0 ° C. over a certain period of time. There is a high possibility of being in a state. Therefore, when the duration of the “first temperature rising state in which the measured value of the second liquid side temperature sensor (65) is equal to or higher than the first end reference temperature T_out1” has reached the first end reference time M_out1 or more (that is, When the first termination condition is satisfied), the surface temperature of the radiant heat exchanger (52) has exceeded 0 ° C over a period of time, and all the ice adhering to the surface of the radiant heat exchanger (52) has melted. It is highly possible that Therefore, when the first termination condition is satisfied, the radiation controller (C2) transmits a melting termination signal to the outdoor controller (C3).

  When the measured value of the second liquid side temperature sensor (65) is higher than the first end reference temperature T_out1, the measured value of the second liquid side temperature sensor (65) is the first end reference temperature T_out1. There is a high possibility that the surface temperature of the radiant heat exchanger (52) is higher than in some cases. Therefore, when the duration of the “second temperature rise state where the measured value of the second liquid side temperature sensor (65) is equal to or higher than the second end reference temperature T_out2” has reached the second end reference time M_out2 (that is, the second When the end condition is satisfied), all the ice adhering to the surface of the radiant heat exchanger (52) is melted even before the duration of the first temperature rising state reaches the first end reference time. Probability is high. Therefore, even if the first end condition is not satisfied, the radiation controller (C2) transmits a melting end signal to the outdoor controller (C3) when the second end condition is satisfied.

  Even if the surface temperature of the radiant heat exchanger (52) remains below 0 ° C for a certain period of time, for example, if the humidity of the indoor air is relatively low, ice on the surface of the radiant heat exchanger (52) It may not adhere or only a small amount of ice may adhere. When the melting operation is performed in such a case, the surface temperature of the radiant heat exchanger (52) reaches a temperature higher than 0 ° C. within a relatively short time from the start of the melting operation. Therefore, in the melting operation performed in such a case, even before the second end reference time M_out2 elapses after the measured value of the liquid side temperature sensor (65) becomes equal to or higher than the second end reference temperature T_out2. There is a high possibility that ice is not already present on the surface of the radiant heat exchanger (52).

  On the other hand, when the third end condition is satisfied, the measured value of the second liquid side temperature sensor (65) reaches the second end reference temperature T_out2 within a relatively short time from the start of the melting operation, and Since the duration of the third temperature rise state is equal to or longer than the third end reference time M_out3, even if the duration of the second temperature rise state is before the second end reference time M_out2, the radiant heat exchanger ( 52) There is a high possibility that ice is not already present on the surface. Therefore, even if the first end condition and the second end condition are not satisfied, the radiation controller (C2) transmits a melting end signal to the outdoor controller (C3) when the third end condition is satisfied. .

-Effect of the embodiment-
In the control system (90) of the present embodiment, the integrated value of the duration of the first low temperature state (state where the measured value of the second liquid side temperature sensor (65) is equal to or lower than the first start reference temperature) is the first start reference. When the time is exceeded (that is, when the first start condition is satisfied), the melting operation for stopping the compressor (21) is started. The first starting reference temperature is 0 ° C. or lower.

  In this embodiment, when the control system (90) stops the compressor (21) and starts the melting operation, the flow of the refrigerant into the radiant heat exchanger (52) stops, and the surface temperature of the radiant heat exchanger (52) Rises. And if the surface temperature of a radiant heat exchanger (52) exceeds 0 degreeC, the ice adhering to the surface of a radiant heat exchanger (52) will melt. Therefore, when the control system (90) performs the melting operation when the first start condition is satisfied, the ice adhering to the surface of the radiant heat exchanger (52) during the cooling operation melts before growing and becoming large. . Therefore, according to this embodiment, it is possible to suppress the growth of ice attached to the surface of the radiant heat exchanger (52) during the cooling operation.

  Further, the control system (90) of the present embodiment starts the melting operation not only when the first start condition is satisfied during the cooling operation but also when the second start condition is satisfied during the cooling operation. That is, in this embodiment, when the integrated value of the duration of the second low temperature state (the state where the measured value of the liquid side temperature sensor (65) is equal to or lower than the second start reference temperature) is equal to or greater than the second start reference time. At the same time, the control system (90) starts the melting operation. The second start reference temperature is lower than the first start reference temperature, and the second start reference time is shorter than the first start reference time. Therefore, according to the present embodiment, it is possible to more reliably suppress the growth of ice attached to the surface of the radiant heat exchanger (52).

  In addition, the control system (90) of the present embodiment is configured so that the duration of the first temperature rise state (state where the measured value of the liquid side temperature sensor (65) is equal to or higher than the first end reference temperature) is equal to or longer than the first end reference time. In such a case, the melting operation is terminated and the cooling operation is restarted. The first end reference temperature is higher than 0 ° C. Therefore, according to the present embodiment, the melting operation can be terminated at an appropriate timing and the cooling operation can be restarted, and a decrease in comfort due to the melting operation can be suppressed.

  Further, the control system (90) of the present embodiment ends the melting operation not only when the first end condition is satisfied during the melting operation but also when the second end condition is satisfied during the melting operation. Restart the cooling operation. That is, in this embodiment, when the duration of the second temperature rise state (the state where the measured value of the liquid temperature sensor (65) is equal to or higher than the second end reference temperature) is equal to or longer than the second end reference time, The control system (90) activates the compressor (21) to resume the cooling operation. The second end reference temperature is higher than the first end reference temperature, and the second end reference time is shorter than the first end reference time. Therefore, according to the present embodiment, it is possible to reduce the possibility of continuing the melting operation even though all the ice adhering to the surface of the radiant heat exchanger (52) has melted, resulting from the melting operation. It is possible to reliably suppress a decrease in comfort.

  In addition, the control system (90) of the present embodiment performs the third end during the melting operation as well as when the first end condition is satisfied during the melting operation and when the second end condition is satisfied during the melting operation. Even when the condition is satisfied, the melting operation is terminated and the cooling operation is restarted. That is, in the control system (90) of the present embodiment, the time until the measured value of the liquid side temperature sensor (65) reaches the second end reference temperature is equal to or shorter than a predetermined determination reference time, and the liquid side temperature sensor When the duration of the state where the measured value of (65) is equal to or higher than the second end reference temperature is equal to or longer than the third end reference time, the compressor (21) is operated to restart the cooling operation. The third end reference time is shorter than the second end reference time. Therefore, according to the present embodiment, it is possible to reduce the possibility of continuing the melting operation even though all the ice adhering to the surface of the radiant heat exchanger (52) has melted, resulting from the melting operation. It is possible to reliably suppress a decrease in comfort.

-Modification 1 of embodiment-
In the present embodiment, the first start condition and the second start condition with which the indoor controller (C1) and the radiation controller (C2) determine success or failure may be the following conditions.

  The first start condition is the duration of the “first low temperature state where the temperature TL of the liquid pipe (34, 53) is equal to or lower than the first start reference temperature T_in1 (TL ≦ T_in1)” (that is, the first low temperature state continuously) The time may be a condition that the first start reference time M_in1 or more.

  The second start condition is that the duration of the “second low temperature state where the temperature TL of the liquid pipe (34, 53) is equal to or lower than the second start reference temperature T_in2 (TL ≦ T_in2)” (that is, the second low temperature state continuously) For example) may be a condition that the second start reference time M_in2 or more.

  Also in this modification, the indoor controller (C1) uses the measured value of the first liquid side temperature sensor (63) as the temperature TL of the liquid pipe (34), and satisfies the first start condition and the second start condition. Judge success or failure. Further, the radiation controller (C2) uses the measurement value of the second liquid side temperature sensor (65) as the temperature TL of the liquid pipe (53) to determine whether the first start condition and the second start condition are successful.

-Modification 2 of embodiment-
In the present embodiment, the first end condition and the second end condition for determining success or failure by the indoor controller (C1) and the radiation controller (C2) may be the following conditions.

  The first end condition is that the integrated value of the duration of the “first temperature rising state where the temperature TL of the liquid pipe (34, 53) is equal to or higher than the first end reference temperature T_out1 (TL ≧ T_out1)” is the first end reference. The condition may be that the time M_out1 or more.

  The second end condition is that the integrated value of the duration of the “second temperature rising state where the temperature TL of the liquid pipe (34, 53) is equal to or higher than the second end reference temperature T_out2 (TL ≧ T_out2)” is the second end reference. The condition may be that the time M_out2 or more.

  Also in this modification, the indoor controller (C1) uses the measurement value of the first liquid side temperature sensor (63) as the temperature TL of the liquid pipe (34), and uses the first end condition, the second end condition, And the success or failure of the third end condition is determined. Further, the radiation controller (C2) uses the measured value of the second liquid side temperature sensor (65) as the temperature TL of the liquid pipe (53), and sets the first end condition, the second end condition, and the third end condition. Judge success or failure.

  While the embodiments and modifications have been described above, it will be understood that various changes in form and details are possible without departing from the spirit and scope of the claims. In addition, the above embodiments and modifications may be appropriately combined or replaced as long as the functions of the subject of the present disclosure are not impaired.

  As described above, the present disclosure is useful for an air conditioner.

10 Air conditioner
11 Refrigerant circuit
16 Gas communication piping (Communication piping)
17 Liquid communication piping (Communication piping)
20 Outdoor unit (heat source unit)
21 Compressor
40 Radiant panel (radiant air conditioning unit)
52 Radiant heat exchanger
53 Liquid pipe (of radiant panel)
65 Second liquid side temperature sensor (liquid side temperature sensor)
90 Control system (controller)

Claims (5)

A radiant air conditioning unit (40) having a radiant heat exchanger (52) includes a refrigerant circuit (11) connected to a heat source unit (20) having a compressor (21) via a connecting pipe (16, 17), and The radiant heat exchanger (52) is an air conditioner that performs at least a cooling operation that functions as an evaporator,
The radiant air conditioning unit (40) includes a liquid pipe (53) for introducing a refrigerant into the radiant heat exchanger (52) during the cooling operation, and a liquid side temperature sensor (for measuring the temperature of the liquid pipe (53)). 65)
A controller (90) configured to perform a melting operation to keep the compressor (21) in a stopped state when a predetermined first start condition is established during the cooling operation;
The first start condition is that the duration of the first low temperature state where the measured value of the liquid side temperature sensor (65) is equal to or lower than the first start reference temperature of 0 ° C. or less, or the integration of the duration of the first low temperature state. An air conditioner characterized in that a value is equal to or greater than a first start reference time. In claim 1,
The controller (90) is configured to perform the melting operation when at least one of the first start condition and a predetermined second start condition is satisfied during the cooling operation,
The second start condition is the duration of the second low temperature state in which the measured value of the liquid side temperature sensor (65) is equal to or lower than the second start reference temperature lower than the first start reference temperature, or the second low temperature state. The air conditioner is characterized in that the integrated value of the continuation time is equal to or longer than a second start reference time shorter than the first start reference time. In claim 1 or 2,
The controller (90) is configured to restart the cooling operation by operating the compressor (21) when a predetermined first end condition is satisfied during the melting operation.
The first end condition is the duration of the first temperature rise state where the measured value of the liquid side temperature sensor (65) is equal to or higher than the first end reference temperature higher than 0 ° C., or the continuation of the first temperature rise state. An air conditioner characterized in that an integrated value of time is equal to or greater than a first end reference time. In claim 3,
The controller (90) activates the compressor (21) to restart the cooling operation when at least one of the first end condition and the predetermined second end condition is satisfied during the melting operation. Configured as
The second end condition is the duration of the second temperature rise state in which the measured value of the liquid side temperature sensor (65) is equal to or higher than the second end reference temperature higher than the first end reference temperature, or the second increase The air conditioner is characterized in that the integrated value of the duration time of the temperature state is a condition that the second end reference time is shorter than the first end reference time. In claim 4,
The controller (90) operates the compressor (21) when at least one of the first end condition, the second end condition, and the predetermined third end condition is satisfied during the melting operation. Configured to resume the cooling operation,
The third end condition is that the time from the start of the melting operation until the measured value of the liquid side temperature sensor (65) reaches the second end reference temperature is equal to or less than a predetermined determination reference time, and the liquid It is a condition that the duration of the state where the measured value of the side temperature sensor (65) is equal to or higher than the second end reference temperature is equal to or longer than a third end reference time shorter than the second end reference time. Air conditioner to do.

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