JP4546067B2 - Air conditioner - Google Patents

Description

  The present invention relates to an air conditioner in which a heat pump type refrigeration cycle is added to a fan coil function for cooling or heating by supplying cold water or hot water, for example, from a heat storage source.

For example, [Patent Document 1] discloses a technique in which a heat pump type refrigeration cycle is added to a fan coil function for cooling or heating by supplying cold water or hot water from a heat storage source.
In particular, as shown in FIG. 4 of [Patent Document 1], a fan coil (water-to-air heat exchanger) for leading heat source water and a refrigeration cycle room in an air passage (duct) for guiding room air. An air heat exchanger (refrigerant to air heat exchanger) corresponding to the heat exchanger is arranged. The refrigeration cycle includes a water-to-refrigerant heat exchanger corresponding to an outdoor heat exchanger, in addition to a compressor, a four-way valve, a pressure reducing device, and the air heat exchanger. And the circuit provided with the three-way valve which switches and guides the heat source water guide | induced from a heat storage source to a fan coil or a water-to-refrigerant heat exchanger, or both.

In normal air conditioning, the refrigeration cycle is stopped and the three-way valve is switched to guide the heat source water to the fan coil to exchange heat with room air. If the three-way valve is switched to drive the refrigeration cycle to circulate the heat source water to the water-to-refrigerant heat exchanger, a heat pump cycle using the heat source water as a heat source is obtained, and cold air or hot air can be obtained in the air heat exchanger. At this time, the heat source water is not led to the fan coil, so there is no heat exchange effect here.
In the cooling / heating operation by the refrigeration cycle, when further improvement in the cooling / heating capacity is required, the three-way valve is controlled to flow the heat source water to both the fan coil and the water-to-refrigerant heat exchanger at the same time. A fan coil and an air heat exchanger are used together, and it can cope with a larger heat load.
Japanese Examined Patent Publication No. 6-68392

However, the technique according to [Patent Document 1] has the following problems.
(1) Water-to-refrigerant heat exchanger that exchanges heat with low-temperature heat source water when cooling operation using a heat pump refrigeration cycle is performed when the temperature of the heat source water (cold water) supplied from the heat storage source is equal to or lower than a predetermined temperature. Thus, the temperature of the condensate refrigerant becomes too low, and normal operation cannot be performed in the heat pump refrigeration cycle, which may cause a failure.
In addition, when heating operation using a heat pump refrigeration cycle is performed when the temperature of the heat source water (hot water) supplied from the heat storage source is equal to or lower than a predetermined temperature, water-to-refrigerant heat exchange in which the low-temperature heat source water becomes a refrigerant evaporator There is a possibility that the heat source water may be further cooled by heat exchange in the vessel and the heat source water may freeze.

(2) Heat pump heating operation is performed while a supply facility that supplies heat source water from a heat storage source (for example, a heat source water supply pump, a water-saving valve that stops water supply when the refrigeration cycle is stopped) has failed for some reason. In this case, a part of the heat source water circulation circuit (particularly, the inside of the water-to-refrigerant heat exchanger) may be frozen in a very short time (about 30 minutes or less).

  The present invention has been made paying attention to the above-mentioned problems, and the object of the present invention is to provide a heat pump type refrigeration cycle for a fan coil function for cooling or heating by supplying cold water or hot water as heat source water from a heat storage source. In addition, when the temperature of the supplied heat source water is below the specified temperature, the refrigeration cycle operation is automatically stopped to prevent the heat source water from freezing and prevent the components from being punctured. It is an object of the present invention to provide an air conditioner that can improve the efficiency.

The present invention has been made in order to satisfy the above-mentioned object, and is provided with a fan coil provided with a conduction path for heat source water and an air heat exchanger provided with a conduction path for refrigerant and a compression path disposed in a ventilation path for indoor air. Machine, four-way valve, air heat exchanger, pressure reducing device, heat pump type refrigeration cycle in which water / refrigerant heat exchanger with heat source water and refrigerant conduction path are sequentially communicated through refrigerant pipe, and required operation Detects the temperature of the refrigerant introduced into the water / refrigerant heat exchanger during heating operation by the refrigeration cycle and the water circulation means that guides the heat source water supplied from the heat source to the fan coil and the water / refrigerant heat exchanger according to the mode The third temperature sensor, the fourth temperature sensor for detecting the temperature of the refrigerant sucked into the compressor constituting the refrigeration cycle, and the temperature detected by the third temperature sensor is equal to or lower than the first predetermined temperature. Or 4th temperature When the detected temperature of the sensor is below a second predetermined temperature, and a heat source water freezing prevention control means for stopping the operation of the compressor,
The heat source water freeze prevention control means further includes a fifth temperature sensor for detecting the temperature of the refrigerant discharged from the compressor, and when the temperature detected by the fifth temperature sensor is equal to or lower than a predetermined temperature when the compressor is started. The heat source water freeze prevention control is performed by the third temperature sensor or the fourth temperature sensor after a predetermined time has elapsed since the compressor was started.

  According to the present invention, on the premise that a heat pump type refrigeration cycle is added to the fan coil function, the temperature of the heat source water is always detected, and the freezing of the heat source water and the puncture of the constituent devices are surely prevented to ensure safety. There is an effect of improving the reliability.

[Example 1]
Hereinafter, an air-conditioning apparatus according to Embodiment 1 of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration of an air conditioner and a piping system diagram.
In the figure, reference numeral 1 denotes a ventilation path (duct) that communicates with the air-conditioned room. A fan coil 2 having a conduction path for heat source water is arranged on the windward side in the ventilation path 1, and the heat source water and the ventilation path. Heat exchange with the air led to 1 is possible. An air heat exchanger 3 corresponding to the indoor heat exchanger of the refrigeration cycle R is arranged on the leeward side of the fan coil 2 in the ventilation path 1 so that heat can be exchanged between the refrigerant and the air guided to the ventilation path 1. Further, a blower 4 for blowing air into the air-conditioned room is installed on the leeward side of the fan coil 2 and the air heat exchanger 3.

A main unit M is disposed at a predetermined portion outside the ventilation path 1 (or inside the ventilation path 1). The main unit M includes a compressor 13, a four-way valve 12, and an electronic device constituting a refrigeration cycle R. An expansion valve (decompression device) 11 and a water / refrigerant heat exchanger 9 to be described later corresponding to an outdoor heat exchanger are arranged except for the air heat exchanger 3, and these components are communicated via a refrigerant pipe P. .
The electronic expansion valve 11 is disposed between the water / refrigerant heat exchanger 9 and the air heat exchanger 3, and controls the degree of superheat of the refrigerant by providing an appropriate throttle. The water / refrigerant heat exchanger 9 includes a conduction path that guides the refrigerant and a conduction path that leads the heat source water, and can exchange heat between the refrigerant and the heat source water.

Further, the main unit M includes a heat source water inlet portion 5 for introducing heat source water (cold water or hot water) supplied from a heat storage source (not shown), and a heat source water outlet portion 10 for returning the heat source water to the heat storage source. The heat source water inlet portion 5 and the heat source water outlet portion 10 constitute an inlet portion and an outlet portion of a heat source water circulation circuit (water circulation means) N accommodated in the main unit M.
As the heat source water circulation circuit N, heat source water supplied from the heat storage source to the heat source water inlet 5 is led to the fan coil 2 via a water / water heat exchanger 6 described later, and the heat source derived from the fan coil 2 Based on the switching operation of the three-way valve 7, the water is led to the water / water heat exchanger 6 again as indicated by the broken arrow in the figure, and further led to the water / refrigerant heat exchanger 9, and then the heat source water outlet 10. The 1st flow path A which returns to a heat storage source via is provided.

The heat source water circulation circuit N directly passes the heat source water led out from the fan coil 2 without passing through the water / water heat exchanger 6 as shown by the solid line arrow based on the switching operation of the three-way valve 7. The second flow path B leading to the water / refrigerant heat exchanger 9 is provided.
The water / water heat exchanger 6 includes a heat source water that communicates the heat source water inlet passage 5 and the heat source water passage that communicates with the fan coil 2, the three-way valve 7, and the water / refrigerant heat exchanger 9 introduction side. The two heat source water conduction paths of the conduction path are provided so as to intersect each other, and the heat source waters exchange heat with each other while being guided through these heat source water conduction paths.

Further, the air conditioner is based on a remote control panel (remote control) (not shown) for giving an instruction of an operation mode, an air volume, and a set temperature to the user, and based on an instruction on the remote control panel, and from a temperature sensor S described later. A control unit (control means) 15 is provided for receiving the detection signal and controlling the blower 4, the compressor 13, the electronic expansion valve 11, the three-way valve 7 and the like based on the detection result and performing an optimum operation.
As the temperature sensor S, a first temperature sensor S1 that detects the temperature of the heat source water immediately after passing through the heat source water inlet portion 5 guided from the heat storage source is provided in the vicinity of the heat source water inlet portion 5. A heat source derived from the water / refrigerant heat exchanger 9 is provided with a second temperature sensor S2 attached to a pipe communicating the water / refrigerant heat exchanger 9 and the heat source water outlet 10 constituting the heat source water circulation circuit N. The temperature of water is detected.

A third temperature sensor S3 is attached to the refrigerant pipe P between the water / refrigerant heat exchanger 9 and the electronic expansion valve 11 constituting the refrigeration cycle R, and water / The temperature of the refrigerant introduced into the refrigerant heat exchanger 9 is detected.
A fourth temperature sensor S4 is attached to the vicinity of the refrigerant suction portion a of the compressor 13 so as to detect the temperature of the refrigerant sucked into the compressor 13. A fifth temperature sensor S5 is attached to the vicinity of the refrigerant discharge portion b of the compressor 13 so that the temperature of the refrigerant discharged from the compressor 13 can be detected.

The first temperature sensor S1 to the fifth temperature sensor S5 are all thermistor type temperature sensors, and detect the temperature of the air, heat source water or refrigerant in the part to which each is attached, and perform the above control. A detection signal is sent to the unit 15.
Next, the operation of the air conditioner configured as described above will be described.

(1) Normal cooling operation and normal heating operation
When the required cooling / heating capacity is not so large and cold water of less than 25 ° C. is supplied during cooling and hot water of 25 ° C. or more is supplied during heating, the control unit 15 instructs the compressor 13 to stop operating. Therefore, there is no heat exchange effect in the air heat exchanger 3, and only the fan coil 2 is controlled to function.
At this time, the control unit 15 switches the three-way valve 7 to circulate the heat source water in the second flow path B, and performs control so that the heat source water does not flow in the first flow path A. The heat source water of the heat storage source is led from the heat source water inlet 5 to the fan coil 2 through the water / water heat exchanger 6, and from the three-way valve 7 to the heat source water outlet 10 through the water / refrigerant heat exchanger 9. It is discharged and returned to the heat storage source.

In this operation mode, heat exchange between the heat source waters is not performed in the water / water heat exchanger 6, and since the refrigeration cycle operation is stopped, the water / refrigerant heat exchanger 9 also has no heat exchange action. Heat source water is led.
Eventually, the fan coil 2 only exchanges heat with the air guided to the ventilation path 1. If cold water is guided to the heat source water circulation circuit N, the indoor cooling operation is performed, and hot water is guided to the heat source water circulation circuit N. If this is done, the room is heated.

(2) High capacity cooling operation and high capacity heating operation
If the difference between the set temperature and the current room temperature becomes large and the capacity becomes insufficient with only the fan coil function, high-performance air conditioning operation is performed in which the capacity is increased by performing the refrigeration cycle operation.
At this time, there is no change in the switching direction of the three-way valve 7 in the heat source water circulation circuit N, which is the same as the normal air conditioning operation described above, but the control unit 15 starts driving the compressor 13 constituting the refrigeration cycle R. At the same time, the switching control of the four-way valve 12 is performed.

  For example, when there is an instruction for high-capacity cooling operation during the supply of cold water, the cold water led from the heat storage source to the heat source water inlet 5 is conducted only in one heat source water passage of the water / water heat exchanger 6 and the other heat source water. Since it is not led to the conduction path, it is led to the fan coil 2 without increasing in temperature by the water / water heat exchanger 6 and absorbs heat from the air led to the ventilation path 1. The air that is led to the fan coil 2 is cooled down as the air is cooled, and the cool air is led to the air heat exchanger 3 arranged on the leeward side of the fan coil 2.

At the same time, the refrigeration cycle operation is performed, the refrigerant condenses in the water / refrigerant heat exchanger 9, the refrigerant evaporates in the air heat exchanger 3, and heat is taken from the cold air after flowing through the fan coil 2. The cool air is changed to cool air whose temperature has further decreased, and is blown into the room. Therefore, high capacity cooling is obtained.
The cold water absorbed by the fan coil 2 is guided from the three-way valve 7 to the water / refrigerant heat exchanger 9 via the second flow path B. In this water / refrigerant heat exchanger 9, since the refrigerant condenses, cold water exchanges heat with the refrigerant and absorbs the heat of condensation. The water / refrigerant heat exchanger 9 is used as a water heat exchanger, and the heat absorption here is used as the cooling heat amount in the refrigeration cycle R, and the cooling temperature is high in efficiency by taking a difference in use temperature compared to the fan coil function alone. It becomes.

When there is an instruction for high-capacity heating operation during the supply of hot water, the hot water led from the heat storage source to the heat source water inlet 5 is led to the fan coil 2 by the water / water heat exchanger 6 without lowering the temperature, and the room air To dissipate heat. As the fan coil 2 releases warm heat into the room air, the room air rises in temperature and changes to warm air, and is led to the air heat exchanger 3.
At the same time, the refrigeration cycle operation is performed, and the refrigerant is condensed in the air heat exchanger 3 to release the heat of condensation to the warm air guided from the fan coil 2. The warm air changes into warm air whose temperature has further increased, and is blown into the room. Therefore, high capacity heating is obtained.
The hot water that has finished radiating heat with the fan coil 2 is guided from the three-way valve 7 to the water / refrigerant heat exchanger 9 via the second flow path B. The refrigerant evaporates in the water / refrigerant heat exchanger 9 and absorbs heat. The hot water whose temperature has been reduced by the fan coil 2 is further deprived of heat by the water / refrigerant heat exchanger 9, and the heat radiation here is used as the amount of heating heat through the refrigeration cycle. A difference is taken and it becomes efficient heating.

(3) Cooling operation when supplying hot water (reverse cooling) and heating operation when supplying cold water (reverse heating)
Hot water of 25 ° C. or higher is supplied from the heat storage source, but there is a demand for emphasizing the cooling operation for some reason in the air-conditioned room. Moreover, although cold water below 25 degreeC is supplied from the heat storage source, there exists a request | requirement which wants to emphasize heating operation by a certain situation in an air-conditioned room. When these requests are made, the control unit 15 switches the conduction direction of the heat source water from the second flow path B to the first flow path A for the three-way valve 7 and then starts the refrigeration cycle operation.

  If there is an instruction for cooling operation during the supply of hot water, the hot water led from the heat storage source to the heat source water inlet 5 is conducted through one heat source water conduction path of the water / water heat exchanger 6 and then led to the fan coil 2. In the fan coil 2, the hot water exchanges heat with the guided air to lower the temperature, and then the other heat source water conduction path of the water / water heat exchanger 6 from the first flow path A according to the switching direction of the three-way valve 7. To exchange heat with the hot water that has passed through the heat source water inlet 5.

The hot water that has been at a high temperature (45 to 50 ° C.) at the heat source water inlet 5 is reduced in temperature (about 30 ° C.) by heat exchange with the water / water heat exchanger 6, and then guided to the fan coil 2. The hot water exchanges heat with the low-temperature air led to the ventilation path 1 and drops to a temperature close to the air temperature (about 25 ° C.), and further, the hot water and the water / water heat exchanger 6 led from the heat source water inlet 5. To exchange heat.
The heating capacity in the fan coil 2 is invalidated, while the operation for the refrigeration cycle R is started. The refrigerant is condensed and cooled in the water / refrigerant heat exchanger 9 to exchange heat with the hot water whose temperature has been lowered, and then the cooling operation is performed in which the refrigerant is led to the air heat exchanger 3 and evaporated. The air heat exchanger 3 obtains a so-called “reverse cooling” action in which heat is taken from the air that has passed through the fan coil 2 and converted into cold air.

  Similarly, when there is an instruction for heating operation during the supply of cold water, the cold water led from the heat storage source to the heat source water inlet 5 is conducted through one heat source water passage of the water / water heat exchanger 6 and then the fan coil 2. Led to. In the fan coil 2, the cold water exchanges heat with air and rises in temperature, and then enters the other heat source water conduction path of the water / water heat exchanger 6 as the first flow path A according to the switching direction of the three-way valve 7. It is guided and exchanges heat with cold water that has passed through the heat source water inlet 5.

Eventually, the cold water, which has been at a low temperature (about 10 ° C.) at the heat source water inlet portion 5, is led to the fan coil 2 after the temperature rises (about 20 ° C.) by exchanging heat with the water / water heat exchanger 6. The cold water exchanges heat with room air and rises to a temperature close to the air temperature (about 25 ° C.), and further exchanges heat with the low-temperature cold water led from the heat source water inlet 5 and the water / water heat exchanger 6.
The cooling capacity of the fan coil 2 is invalidated, while the operation for the refrigeration cycle R is started. The refrigerant discharged from the compressor 13 is led to the air heat exchanger 3 where the heating operation for condensation is performed. Then, the refrigerant is guided to the water / refrigerant heat exchanger 9, and heat is exchanged with the cold water whose temperature has been increased by heating, whereby the refrigerant evaporates. The air heat exchanger 3 obtains a so-called “reverse heating” action in which condensation heat is applied to the air after flowing through the fan coil 2 to change it into warm air.

By the way, the above-described reverse heating operation is performed in a state where cold water is supplied from a heat storage source such as early spring or late autumn, but a heating action is desired due to a sudden drop in temperature. That is, since cold water is supplied as the heat source water, if the temperature is lowered, the cold water circulating through the heat source water circulation circuit N may be frozen due to the influence.
The control unit 15 always detects the temperature signal of the heat source water (cold water) sent from the first temperature sensor S1 attached between the heat source water inlet 5 and the heat source water introduction part of the water / water heat exchanger 6. And a detection temperature signal of the heat source water sent from the second temperature sensor S2 attached between the heat source water outlet portion and the heat source water outlet portion 10 of the water / refrigerant heat exchanger 9 is stored in the storage circuit. Comparison with reference temperature.

And the control part 15 implements freeze prevention control of the heat source water which circulates through the heat source water circulation circuit N on predetermined conditions. Specifically, if the detected temperature of either the first temperature sensor S1 or the second temperature sensor S2 is less than 2 ° C. and the detected temperature continues for 30 seconds or more, the signal is immediately compressed. An operation stop signal is sent to the machine 13 to stop the operation of the compressor 13.
The heat source water has a water temperature just before natural freezing, and if the refrigeration cycle operation is performed, the heat source water is deprived of heat in the water / refrigerant heat exchanger 9 that performs the evaporation of the refrigerant. Therefore, the heat source water circulating through the heat source water circulation circuit N can be reliably prevented from freezing. And the heat source water does not freeze in the component equipment which comprises the heat source water circulation circuit N, especially the heat source water conduction path of the water / refrigerant heat exchanger 9, and a puncture accident can be prevented.

Even in this state, the supply of the heat source water is continued, and both the first temperature sensor S1 and the second temperature sensor S2 that subsequently detect the temperature of the heat source water send signals that detect 4 ° C. or higher. 15, the control unit 15 determines that the operation has returned to normal and returns the operation of the compressor 13. Therefore, the reverse heating operation is performed in a state where the heat source water is circulating while preventing the heat source water from freezing.
If the first temperature sensor S1 and the second temperature sensor S2 fail for some reason and send an abnormal temperature detection signal, the control unit 15 determines that the sensor is abnormal and determines that the compressor 13 Stop operation.

  Further, instead of the first temperature sensor S1 and the second temperature sensor S2 described above, a temperature sensor made of a bimetal thermo is arranged at the heat source water outlet 10 simply from the water / refrigerant heat exchanger 9. A configuration for detecting the temperature of the heat source water led out to the heat source water outlet 10 is conceivable. Specifically, when the bimetal thermostat detects a predetermined temperature (for example, 0 ° C.), the operation / stop relay of the compressor 13 is shut off, and when it detects that the temperature has returned to an increase (for example, 6 ° C.), the operation / stop relay is turned on. Control to connect.

  However, the bimetal thermo has an operating point and a return point, and only one of them can adjust the accuracy. When adjustment in manufacturing is performed with priority given to the operating point (for example, 0 ° C.), the return point (for example, 6 ° C.) actually becomes 4 ° C. to 8 ° C. Once the compressor is stopped to prevent freezing of the heat source water, it cannot be restored for a long time. During this time, the room temperature decreases and the basic function as an air conditioner is impaired.

  In the above-described embodiment, the thermistor temperature sensors are used for all the temperature sensors S1 to S5, so that the operating temperature and the return temperature are both highly accurate and do not require adjustment in manufacturing. Depending on the setting of the return temperature, when the compressor 13 is stopped to prevent freezing of the heat source water in the heat source water circulation circuit N, the operation of the compressor is resumed after about 3 minutes, so that the room temperature is hardly lowered. I can't see it. That is, it is possible to prevent the heat source water from freezing and the worst-case component puncture accident without impairing the heating operation performance that is the basic function of the air conditioner.

[Example 2]
During the so-called reverse heating operation, when the supply facility that sends the heat source water from the heat storage source fails for some reason and water supply is not performed for that reason, the control unit 15 prevents freezing of the heat source water in the heat source water circulation circuit N. To control.
That is, when cold water is not led to the heat source water circulation circuit N due to a pump failure or the like and does not circulate, it is confirmed that when the heat pump heating operation by the refrigeration cycle R is performed, the cold water freezes in a short time (within about 30 minutes). It was. In particular, since the refrigerant evaporates and takes heat away in the water / refrigerant heat exchanger 9, the cold water on the side of the water conduction path where there is no movement of water quickly freezes.

Although it is only necessary to detect the temperature of the water conduction path inside the water / refrigerant heat exchanger 9, it is actually difficult to detect the temperature inside. When the supply of the heat source water is stopped and the heat source water does not circulate in the heat source water circulation circuit N, the water temperature detection signals from the first temperature sensor S1 and the second temperature sensor S2 are not determined.
Therefore, the control unit 15 receives detection signals from the third temperature sensor S3 provided on the refrigerant introduction side of the water / refrigerant heat exchanger 9 and the fourth temperature sensor S4 provided on the suction unit of the compressor 13. Compared to the reference value stored in the storage circuit, it is determined that the heat source water supply facility has failed for some reason under a predetermined condition, and water supply has not been performed for that reason, and the heat source water circulation circuit N To prevent freezing of the heat source water in

  Specifically, the detected temperature TE of the third temperature sensor S3 provided on the refrigerant introduction side of the water / refrigerant heat exchanger 9 is less than −5 ° C., or is provided in the suction portion a of the compressor 13. When the detected temperature TS of the temperature sensor S4 of 4 is less than 0 ° C. and a detection signal is sent to the control unit 15, control is performed to stop the operation of the compressor 13 assuming that the freeze prevention determination condition is satisfied. Therefore, freezing of the heat exchange water (cold water) circulating in the heat source water circulation circuit N can be reliably prevented.

  Then, the control unit 15 activates a built-in restart timer in synchronism with the operation stop of the compressor 13, and after the elapse of a predetermined time (for example, 2 minutes 30 seconds), the third temperature sensor S3 and the fourth temperature sensor again. The detection signal of S4 is taken in and it is determined whether or not the above-described anti-freezing determination condition is met. The control unit 15 confirms that the anti-freezing determination condition is not satisfied, and then restarts the compressor 13 for the second time.

  Even after the compressor 13 is restarted, the third temperature sensor S3 and the fourth temperature sensor S4 detect the refrigerant temperatures at the respective attachment sites and send the detection signals to the control unit 15. When the control unit 15 receives the detection signal that the detection temperature TE of the third temperature sensor S3 is less than −5 ° C. or the detection temperature TS of the fourth temperature sensor S4 is less than 0 ° C., It is determined that the freeze prevention determination condition is satisfied, and control is performed so as to stop the operation of the compressor 13.

  The control unit 15 activates the restart timer in the same manner as immediately before the operation of the compressor 13 is stopped, and after confirming that the above-described anti-freezing determination condition is not satisfied after a predetermined time (for example, 2 minutes and 30 seconds) has elapsed. Then, the compressor 13 is restarted for the third time. When the freeze prevention determination condition is satisfied again, control is performed to stop the operation of the compressor 13, and “abnormal water supply” is determined and an abnormal code is displayed.

Thus, for example, in the state where the heat source water is not supplied to the heat source water circulation circuit N because the pump for supplying the heat source water (cold water) breaks down and the heat source water is not supplied, the inside of the water / refrigerant heat exchanger 9 in particular. Even if the temperature of the heat source water conduction path is not detected, the compressor 13 is controlled from the temperature detection on the refrigeration cycle R side by the third temperature sensor S3 and the fourth temperature sensor S4 to prevent the heat source water from freezing. And the puncture of the component equipment can be prevented.
Similar to the first embodiment, if the third temperature sensor S3 and the fourth temperature sensor S4 fail for some reason and send an abnormal temperature detection signal, the control unit 15 detects the sensor. It is determined that there is an abnormality and the operation of the compressor 13 is stopped.

  By the way, while the operation of the compressor 13 is stopped for a long time, the compressor 13 may be cooled. At this time, the third temperature sensor S3 provided on the refrigerant introduction side of the water / refrigerant heat exchanger 9 and the fourth temperature sensor S4 provided on the suction portion a of the compressor 13 If the temperature is lower than that, the control unit 15 that performs control based on the detection signal may deviate from the actual determination.

In order to estimate such a state of the compressor 13, the discharge part b of the compressor 13 is provided with a fifth temperature sensor S5, and the control unit 15 always receives a detection signal from the fifth temperature sensor S5. In addition to the judgment conditions.
Specifically, upon receiving a detection signal that the detection temperature TD of the fifth temperature sensor S5 is less than 25 ° C., the control unit 15 sets the elapsed time (3 minutes) after the start of the compressor 13 to the freeze prevention. Add to judgment conditions.

  Since the refrigeration cycle becomes a daily state by setting the above-mentioned delay elapsed time (3 minutes), the air conditioner side when the heat source water supply equipment is operating normally, such as when the water supply is delayed or returned to normal It is possible to prevent the compressor 13 from being stopped due to the erroneous determination. In order to fear freezing and puncture, the basic function such as stopping the compressor 13 (that is, stopping the operation of the air conditioner) is not spoiled.

  As described above, when the detection temperature TE of the third temperature sensor S3 is less than −5 ° C. or the detection temperature TS of the fourth temperature sensor S4 is detected to be less than 0 ° C., the freeze prevention determination condition is satisfied. Therefore, the control unit 15 stops the operation of the compressor 13 and activates the restart timer at the same timing. After a predetermined time (for example, 2 minutes and 30 seconds) has elapsed, the control unit 15 confirms that the anti-freezing determination condition is not met. After confirmation, the compressor 13 is restarted for the second time.

When the compressor 13 is restarted and the operation is continued for a predetermined time (for example, 60 minutes), that is, when the compressor 13 is not stopped without satisfying the freeze prevention determination condition, the control unit 15 Clears the third start / stop count of the compressor 13 described in the second embodiment.
Further, the start / stop count of the compressor 13 in the heat source water freeze prevention control is also cleared by stopping the compressor 13 due to other factors such as operation stop by remote control (remote controller) operation or thermo control.

As described above, since the count of the number of stops of the compressor 13 in the heat source water freeze prevention control is cleared, when the water supply operation of the heat source water supply facility is delayed or returned to normal, the water is normally supplied by a trivial matter. The operation stop of the compressor 13 due to the erroneous determination on the air conditioner side can be suppressed.
Of course, the heat source water freezing prevention control is effective at any time during the reverse heating operation only by clearing the count. While avoiding freezing punctures in the components, it is possible to avoid as much as possible the unnecessary operation stop of the compressor 13 (that is, the operation stop of the air conditioner) and the abnormal code display by the “abnormal water supply” determination. it can.

[Example 3]
Next, a third embodiment of the present invention will be described with reference to the drawings.
FIG. 2 is a schematic configuration of an air conditioner and a piping system diagram.
Although the position of the blower 4 is different from the position in the first embodiment described above in the ventilation path 1, heat is exchanged by blowing air to the fan coil 2 and the air heat exchanger 3 arranged in the ventilation path 1. The air after the heat exchange is guided to the room is not changed.

  The first temperature sensor S1 is attached to the outlet portion of the heat source water conduction path of the fan coil 2, and the second temperature sensor S2 is attached to the intermediate part of the refrigerant conduction path of the air heat exchanger 3. In the main unit Ma, the same heat pump refrigeration cycle R as described above is accommodated except for the air heat exchanger 3, and the same components are assigned the same numbers and a new description is given. Is omitted.

As the heat source water circulation circuit Na, a three-way valve 7 is connected directly from the heat source water inlet 5, the remaining port of the three-way valve 7 is connected to the fan coil 2, and the other port is connected to the water / refrigerant heat exchanger 9. The fan coil 2 communicates with an intermediate portion of a pipe communicating with the fan coil 2. The water / refrigerant heat exchanger 9 and the heat source water outlet 10 are not changed in direct communication.
As the temperature sensor S, a first temperature sensor S1 is attached to a pipe between the heat source water inlet 5 and the three-way valve 7 to detect the temperature of the heat source water immediately after being introduced into the heat source water circulation circuit Na. The second temperature sensor S2 is attached to a pipe communicating the water / refrigerant heat exchanger 9 and the heat source water outlet 10 constituting the heat source water circulation circuit Na, and the heat source water derived from the water / refrigerant heat exchanger 9 is provided. Detect temperature.

  A third temperature sensor S3 is attached to the refrigerant pipe P between the water / refrigerant heat exchanger 9 and the electronic expansion valve 11 constituting the refrigeration cycle R, and water / refrigerant heat exchange is performed during heating operation by the refrigeration cycle R. The temperature of the refrigerant introduced into the vessel 9 is detected. A fourth temperature sensor S4 is attached to the vicinity of the refrigerant suction portion a of the compressor 13, and detects the temperature of the refrigerant sucked into the compressor 13. A fifth temperature sensor S5 is attached to the vicinity of the refrigerant discharge portion b of the compressor 13 to detect the temperature of the refrigerant discharged from the compressor 13.

In the air conditioner configured as described above, in the case of normal cooling, cold water is supplied as heat source water, and the three-way valve 7 is directly guided to the fan coil 2 as indicated by the solid line arrow to release cold heat. The air guided to the ventilation path 1 by driving the blower 4 is changed into cold air and guided to the room through the air heat exchanger 3. The refrigeration cycle R is stopped, and the heat exchange action in the air heat exchanger 3 is not performed.
The chilled water whose temperature has risen derived from the fan coil 2 is led to the water / refrigerant heat exchanger 9, but since there is no heat exchanging action here, it is led out from the heat source water outlet section 10 at that temperature. In the case of normal heating, the only difference is that hot water is supplied as the heat source water, the circulation path of the hot water is not changed, and the refrigeration cycle operation is not changed.

In the case of high-capacity cooling, cold water is introduced as heat source water, and the cold water is circulated in the same manner as normal cooling. At the same time, the operation of the refrigeration cycle R is started, and there is a discharge of cold heat by the fan coil 2 and a discharge of cold heat by the air heat exchanger 3, and a high-capacity cooling operation is obtained. In the case of high-capacity heating, hot water is introduced as heat source water, and hot water is circulated in the same manner as in normal heating, and at the same time, the operation of the refrigeration cycle R is started. There is discharge of warm heat by the fan coil 2 and discharge of warm heat by the air heat exchanger 3, and a high-performance heating operation can be obtained.
In the case of the reverse cooling operation when hot water is guided as the heat source water, the three-way valve 7 is switched in the direction indicated by the broken line arrow in the figure. The hot water introduced from the heat source water inlet 5 is guided to the water / refrigerant heat exchanger 9 along the switching direction of the three-way valve 7 and is discharged from the heat source water outlet 10 as it is.

The refrigeration cycle R performs a cooling operation, and cold air is released in the air heat exchanger 3. Since hot water is not guided to the fan coil 2, the fan coil 2 has no function. The hot water is guided to the water / refrigerant heat exchanger 9 and absorbs the heat of condensation before being discharged. That is, by guiding the hot water to the water / refrigerant heat exchanger 9, a function of lowering the high pressure to some extent can be obtained.
Also in the case of reverse heating operation when cold water is guided as heat source water, the three-way valve 7 is switched in the direction indicated by the broken line arrow in the figure. The cold water introduced from the heat source water inlet 5 is guided to the water / refrigerant heat exchanger 9 along the switching direction of the three-way valve 7 and is discharged from the heat source water outlet 10 as it is.

The refrigeration cycle R performs heating operation, and condensation heat is released in the air heat exchanger 3. Since the cold water is not guided to the fan coil 2, the fan coil 2 has no function. The cold water is led to the water / refrigerant heat exchanger 9, where the latent heat of vaporization is taken away and discharged. That is, by introducing cold water to the water / refrigerant heat exchanger 9, a function of increasing the low pressure to some extent can be obtained.
The control unit 15 always detects the detection temperature signal of the heat source water sent from the first temperature sensor S1 attached between the heat source water inlet 5 and the heat source water introduction part of the water / water heat exchanger 6, and the water / water The detected temperature signal of the heat source water sent from the second temperature sensor S2 attached between the heat source water outlet portion and the heat source water outlet portion 10 of the refrigerant heat exchanger 9 is compared with the stored reference temperature.

And the control part 15 implements freeze prevention control of the heat source water which circulates through the heat source water circulation circuit N on predetermined conditions. The specific numerical values of the heat source water freeze prevention control conditions may be exactly the same as the conditions described in the first embodiment, and therefore, a new description is omitted here by applying the same embodiment.
Further, the control unit 15 detects a temperature detected by a third temperature sensor S3 provided between the water / refrigerant heat exchanger 9 and the electronic expansion valve 11, and a fourth temperature sensor S4 attached to the suction unit of the compressor 13. From this, it is determined that the heat source water supply facility has failed for some reason and water supply has not been performed, and the heat source water circulation circuit N is prevented from freezing. Since the specific numerical value of the heat source water freeze prevention control condition may be exactly the same as the condition described in the second embodiment, a new description is omitted here by applying the same embodiment.

When the control unit 15 receives a detection signal from the fifth temperature sensor S5 attached to the discharge unit b of the compressor 13 and receives a detection signal having a temperature lower than a predetermined temperature, the control unit 15 compresses the freezing prevention determination condition. It is also the same that control is performed by delaying the elapsed time after the machine 13 is activated.
The control unit 15 is also configured to clear the start / stop count of the compressor 13 in the heat source water freeze prevention control when the compressor 13 continues operation for a predetermined time after the start, that is, the operation by remote control operation. The same applies to clearing the start / stop count of the compressor 13 under the heat source water freeze prevention control even when the compressor 13 is stopped due to other factors such as stoppage or thermo control.
Further, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention, and the present invention completely includes all of them. .

The schematic structure and piping figure of the air conditioning apparatus which concern on Example 1 and Example 2 of this invention. The schematic structure and piping figure of the air conditioning apparatus based on Example 3 of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Ventilation path, 2 ... Fan coil, 3 ... Air heat exchanger, 4 ... Blower, 13 ... Compressor, 12 ... Four-way valve, 11 ... Pressure-reducing device (electronic expansion valve), 9 ... Water / refrigerant heat exchanger, R ... refrigeration cycle, N ... heat source water circulation circuit (water circulation means), S1 ... first temperature sensor, S2 ... second temperature sensor, 15 ... control unit (control means), S3 ... third temperature sensor, S4 ... 4th temperature sensor, S5 ... 5th temperature sensor.

Claims (1)

A fan coil disposed in the indoor air ventilation path and provided with a heat source water conduction path; and an air heat exchanger provided with a refrigerant conduction path;
A heat pump type refrigeration cycle in which a water / refrigerant heat exchanger having a compressor, a four-way valve, the air heat exchanger, a pressure reducing device, a heat source water and a refrigerant passage is sequentially communicated via a refrigerant pipe;
Water circulation means for guiding heat source water supplied from a heat source to the fan coil and the water / refrigerant heat exchanger according to a required operation mode;
A third temperature sensor for detecting the temperature of the refrigerant introduced into the water / refrigerant heat exchanger during heating operation by the refrigeration cycle;
A fourth temperature sensor for detecting the temperature of the refrigerant sucked into the compressor constituting the refrigeration cycle;
When the temperature detected by the third temperature sensor falls below the first predetermined temperature, or when the temperature detected by the fourth temperature sensor falls below the second predetermined temperature, the compressor is stopped. Heat source water freeze prevention control means,
The heat source water freeze prevention control means further includes a fifth temperature sensor for detecting the temperature of the refrigerant discharged from the compressor, and the detected temperature of the fifth temperature sensor is equal to or lower than a predetermined temperature when the compressor is started. The air conditioner is characterized in that heat source water freeze prevention control is performed by the third temperature sensor or the fourth temperature sensor after a predetermined time has elapsed since starting the compressor.

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