JP3676019B2 - Refrigerant heating type air conditioner - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a refrigerant heating air conditioner, and more particularly to a technique for preventing freezing of brine in a water pipe connected to a water heat exchanger.
[0002]
[Prior art]
In recent years, heat pump type air conditioners that perform heating using air as a heat source are increasing in place of conventional cooling only machines.
[0003]
However, in a heat pump type air conditioner, when the outside air temperature is extremely low, the difference between the evaporation temperature of the refrigerant in the outdoor heat exchanger (air heat exchanger) and the outside air temperature becomes very small, and heating becomes almost impossible. was there. Therefore, in addition to a normal air heat exchanger, a water heat exchanger (refrigerant heater) is provided in the outdoor unit, and between the refrigerant and the heated brine (antifreeze) supplied from a heated brine supply source (boiler, etc.). By performing the heat exchange (that is, refrigerant heating), a refrigerant heating type that supplies a relatively high-temperature refrigerant to the compressor has appeared. In the refrigerant-heated air conditioner, the latent heat of condensation in the indoor heat exchanger can be ensured regardless of the outside air temperature, so that sufficient heating is possible even in severe winter. In addition, in order to detect whether or not heat exchange is being performed in the water heat exchanger, water temperature sensors are attached to the inlet side water pipe and the outlet side water pipe to detect the inlet side water temperature and the outlet side water temperature. Is done.
[0004]
[Problems to be solved by the invention]
In the above-described refrigerant heating type air conditioner, when the operation of the air conditioner is stopped in severe winter, there is a possibility that the water pipe connecting the heating brine supply source and the water heat exchanger may be damaged.
[0005]
In general, supply of heated brine to the water heat exchanger is performed only during the heating operation of the air conditioner. Therefore, in a factory or an office building on a holiday, the brine stays in the water pipe exposed to the outside air. become. Brine is difficult to freeze even when the water temperature is lowered to about −20 ° C., but when it is exposed to a lower temperature for a long time, it freezes in the water pipe depending on the composition (weight ratio of ethylene glycol or the like). In this case, the water pipe is cracked due to the volume expansion of the brine, and even if the heating brine is supplied again along with the heating operation of the air conditioner, the heating brine flows out from the crack and the refrigerant cannot be heated. As a result, repair work such as pipe replacement is required, and sufficient heating is not performed until the repair work is completed, so that the function as an air conditioner is significantly impaired.
[0006]
This invention is made | formed in view of the said condition, and it aims at providing the refrigerant | coolant heating type air conditioner which prevented the freezing of the brine in the water piping connected to a water heat exchanger.
[0007]
[Means for Solving the Problems]
In order to solve the above problems, in the invention of claim 1, an outdoor unit having a water heat exchanger and a compressor used for refrigerant heating, an indoor unit connected to the outdoor unit via a refrigerant circuit, A heating brine supply source for supplying heating brine to the water heat exchanger, an inlet side water temperature sensor for detecting inlet side hot water of the water heat exchanger, and an outlet side for detecting outlet water temperature of the water heat exchanger In a refrigerant heating air conditioner comprising a water temperature sensor, the inlet side water temperature and the outlet side water temperature are detected at predetermined time intervals while the compressor is stopped, and the inlet side water temperature and the outlet side water temperature are If at least one of is the first predetermined temperature or less and the second predetermined temperature or higher, it is operated the heating brine source, equipped with a heating brine supply control means for heating the brine circulating into the water heat exchanger We propose that the.
[0008]
According to the present invention, for example, when the inlet side water temperature or the outlet side water temperature of the water heat exchanger becomes equal to or lower than the first predetermined temperature while the air conditioner is stopped, the heated brine supply control means supplies water to the heated brine supply source. Heat brine is supplied to the heat exchanger to prevent freezing of the brine in the water piping. Even if either one of the water temperature sensors fails, the detected value is lower than the second predetermined temperature, so that the control by the heating brine supply control means is performed based on the detected value of the normal water temperature sensor.
[0009]
According to a second aspect of the present invention, an outdoor unit having a water heat exchanger and a compressor used for refrigerant heating, an indoor unit connected to the outdoor unit via a refrigerant circuit, and the water heat exchanger A refrigerant comprising a heated brine supply source for supplying heated brine to the inlet, an inlet-side water temperature sensor for detecting the inlet-side water temperature of the water heat exchanger, and an outlet-side water temperature sensor for detecting the outlet-side water temperature of the water heat exchanger. In the heating type air conditioner, when the compressor is stopped, the inlet side water temperature and the outlet side water temperature are detected at predetermined time intervals, and at least one of the inlet side water temperature and the outlet side water temperature is a first predetermined temperature. If the temperature or less and the second predetermined temperature or higher, the heating brine supply source by running heated brine circulating into the water heat exchanger, at least one of a third predetermined between the inlet-side water temperature and the outlet temperature If it exceeds over the time to a predetermined time, provides that the regardless of the operating conditions of the outdoor unit, equipped with a heating brine supply control means to stop the supply of the heating brine is stopped the heating brine source .
[0010]
According to the present invention, for example, when the inlet side water temperature or the outlet side water temperature of the water heat exchanger becomes equal to or lower than the first predetermined temperature while the air conditioner is stopped, the heated brine supply control means supplies water to the heated brine supply source. Heat brine is supplied to the heat exchanger to prevent freezing of the brine in the water piping. Then, when the inlet side water temperature or the outlet side water temperature exceeds the third predetermined temperature for a predetermined time due to an increase in the outside air temperature or supply of heated brine, the inlet side water temperature or the outlet side water temperature again becomes equal to or lower than the first predetermined temperature. Until the heating brine supply is stopped.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic configuration diagram of a refrigerant heating air conditioner including one outdoor unit 1 and a plurality of indoor units 3a, 3b,... (Hereinafter, represented as indoor units 3a, 3b). In the figure, the refrigerant circuit is indicated by a solid line, and the electric circuit is indicated by a one-dot chain line.
[0012]
In the outdoor unit 1, a variable capacity compressor 5 using an inverter, an electromagnetic four-way valve 7, an air heat exchanger 9 and a water heat exchanger 11 arranged in parallel, an accumulator 13, an electric fan 15, etc. And an outdoor ECU 17 that controls the drive of the compressor 5, the four-way valve 7, the electric fan 15, and the like.
[0013]
The outdoor ECU 17 includes an input / output interface, a ROM, a RAM, a timer counter, and the like in addition to the CPU serving as a control center. The input interface includes an inlet temperature Tri and an intermediate temperature of the air heat exchanger 9. In addition to the liquid temperature sensor 41 and the coil temperature sensor 43 for detecting Trm, various sensors such as an inlet water temperature sensor 45 and an outlet water temperature sensor 47 for detecting the inlet side water temperature Twi and the outlet side water temperature Two of the water heat exchanger 11 are provided. Connected.
[0014]
In the indoor units 3a and 3b, an indoor heat exchanger 21, an electric fan 23, an electric expansion valve 25, and the like, and an indoor ECU 27 that drives and controls the electric fan 23 and the electric expansion valve 25 are accommodated. ing.
[0015]
The equipment in the outdoor unit 1 and each of the indoor units 3a and 3b are connected by refrigerant pipes 51 to 64. The refrigerant circulates in the direction indicated by the solid line arrow during the refrigerant heating operation, and the broken line in the normal heating operation. The refrigerant circulates in the direction indicated by the arrow. In the figure, 31 and 33 are electromagnetic shut-off valves that are opened and closed by the outdoor ECU 17 and close the refrigerant pipes 58 and 61 to the air heat exchanger 9 or the water heat exchanger 11. Reference numeral 35 denotes a check valve that allows the refrigerant to flow only in one direction, and is interposed in the pipe of the refrigerant pipe 60.
[0016]
The water heat exchanger 11 is connected to a boiler 75 serving as a heating brine supply source via two water pipes 71 and 73. Both the water pipes 71 and 73 are equipped with the above-described inlet water temperature sensor 45 and outlet water temperature sensor 47, respectively, and the temperature of the brine flowing through the pipes by these water temperature sensors 45 and 47 is the inlet side water temperature Twi and the outlet side. It is detected as the water temperature Two. The outdoor ECU 17 is connected to a control board (not shown) of the boiler 75 and performs operation control (ignition / combustion control, brine temperature control, water pump drive control, etc.) of the boiler 75.
[0017]
Hereinafter, the operation of the present embodiment will be described.
[0018]
In the air conditioner of the present embodiment, the cooling operation or the heating operation is performed by switching the four-way valve 7 by the outdoor ECU 17. When the outside air temperature falls below a predetermined temperature and heating using air as a heat source cannot be performed, the outdoor ECU 17 switches from the normal heating operation to the refrigerant heating / heating operation. That is, the shut-off valve 31 is opened while the shut-off valve 31 is closed, and the supply destination of the liquid refrigerant from each of the indoor units 3a and 3b is changed from the air heat exchanger 9 to the water heat exchanger 11. Then, the electric fan 15 is stopped, and the heating brine is supplied from the boiler 75 to the water heat exchanger 11.
[0019]
As a result, the liquid refrigerant from the indoor heat exchanger 21 flows into the water heat exchanger 11 via the refrigerant pipes 57 and 61, and is relatively hot (for example, 20 to 40) by heat exchange with the heating brine therein. ° C) gas refrigerant. The gas refrigerant flows into the accumulator 13 through the refrigerant pipes 62 and 63 and is further sucked into the compressor 5 through the refrigerant pipe 64. The gas refrigerant sucked into the compressor 5 is compressed and becomes high temperature and high pressure, and flows into the indoor heat exchanger 21 of each indoor unit 3a, 3b via the refrigerant pipes 51-54. The high-temperature gas refrigerant gradually condenses in the indoor heat exchanger 21 and becomes liquid refrigerant again while heating the indoor air blown to the electric fan 23 by releasing heat energy.
[0020]
In the present embodiment, when the main power supply is turned on to the air conditioner, the outdoor ECU 17 is set at a predetermined control interval regardless of the operation state of the outdoor unit 1 (during operation, stop, alarm output, etc.) in FIG. The heating brine supply control subroutine shown in FIG. 3 is repeatedly executed. When the outdoor ECU 17 starts this subroutine, it first reads the inlet side water temperature Twi and the outlet side water temperature Two detected by the water temperature sensors 45 and 47 in step S1 of FIG. 2, and then the heating brine supply flag FHB is set in step S3. It is determined whether or not 1. The heating brine supply flag FHB is a flag indicating that the heating brine is supplied from the boiler 75 to the water heat exchanger 11, and its initial value is set to zero.
[0021]
Since the determination in step S3 is No (negative) in the initial control, the outdoor ECU 17 determines that the inlet side water temperature Twi is equal to or lower than the first predetermined temperature Tw1 (−18 ° C. in the present embodiment) in step S5. It is determined whether or not the temperature is equal to or higher than the temperature Tw2 (in this embodiment, −40 ° C.). If the determination in step S5 is No, the outdoor ECU 17 further determines in step S7 whether or not the outlet water temperature Two is equal to or lower than the first predetermined temperature Tw1 and equal to or higher than the second predetermined temperature Tw2. If No, return to the start and repeat the control.
[0022]
Here, the first predetermined temperature Tw1 is a temperature at which the brine is likely to freeze, and when the detection result of the water temperature sensors 45 and 47 falls below the first predetermined temperature Tw1, the temperature decrease is quickly eliminated. There is a need. Further, the second predetermined temperature Tw2 is a temperature that is impossible in normal times, and is recognized by the outdoor ECU 17 only when the water temperature sensors 45 and 47 fail or when the lead wires are disconnected. Therefore, when the outdoor side ECU 17 recognizes that the inlet side water temperature Twi or the outlet side water temperature Two has fallen below the second predetermined temperature Tw2, the outdoor ECU 17 turns on a warning lamp to notify that a sensor failure has occurred. Is performed by a subroutine not described here.
[0023]
On the other hand, when the determination in step S5 or step S7 becomes Yes (positive) due to a decrease in the outside air temperature, the outdoor ECU 17 starts supplying the heating brine to the water heat exchanger 11 to the boiler 75 in step S9. In step S11, the heating brine supply flag FHB is set to 1. Thereby, the temperature of the brine which distribute | circulates the inside of both the water piping 71 and 73 rises rapidly, and the freezing which becomes a damage factor of the water piping 71 and 73 is prevented beforehand.
[0024]
After the supply of the heating brine is started, the determination in step S3 is Yes, so that the outdoor ECU 17 proceeds to step S13 in FIG. 3, and the inlet side water temperature Twi is set to the third predetermined temperature Tw3 (in this embodiment). , 40 ° C.) or below a second predetermined temperature Tw2. If the determination in step S13 is Yes due to a temperature rise due to the supply of heated brine or a failure of the water temperature sensors 45, 47, the outdoor ECU 17 determines whether the outlet water temperature Two has exceeded the third predetermined temperature Tw3 in step S15. Alternatively, it is further determined whether or not the temperature falls below the second predetermined temperature Tw2.
[0025]
If the determination in step S15 is also Yes, the outdoor ECU 17 determines whether or not the timer start flag Fts having an initial value 0 is 1 in step S17. Since this determination is No for the first time, the outdoor ECU 17 starts measuring time with the built-in timer t in step S19, sets the timer start flag Fts to 1 in step S21, and returns to the start. If the determination in steps S13 and S15 is Yes again next time, the outdoor ECU 17 determines whether or not the time measured by the timer t has reached a predetermined time ta (10 seconds in the present embodiment) in step S23. However, while this determination is No, the determinations in steps S13 and S15 are repeated.
[0026]
When the determinations in steps S13 and S15 are Yes over a predetermined time ta, the outdoor ECU 17 stops supplying the heating brine to the hydrothermal exchanger 11 to the boiler 75 in step S25, and the heating brine in step S27. The supply flag FHB and the timer start flag Fts are reset to zero. Thereby, the operation of the boiler 75 is stopped and the consumption of energy is suppressed until the determination in step S5 or step S7 becomes Yes again.
[0027]
When the determination in step S13 or step S15 becomes No for some reason after the timer t starts counting, the outdoor ECU 17 resets the timer start flag Fts to 0 in step S29. In this case, even if the determinations in steps S13 and S15 are Yes again, the timing by the timer t is newly started from that point. That is, in this embodiment, the supply of the heating brine is stopped only when the inlet side water temperature Twi and the outlet side water temperature Two exceed the third predetermined temperature Tw3 over a predetermined time ta, Hunting in operation control is prevented.
[0028]
As described above, in this embodiment, since the supply control of the heating brine to the hydrothermal exchanger 11 is performed based on the inlet side water temperature Twi and the outlet side water temperature Two regardless of the operating state of the air conditioner, the severe winter The freezing of the brine in the water pipes 71 and 73 at the time can be effectively prevented. In addition, when the inlet side water temperature Twi or the outlet side water temperature Two falls below the second predetermined temperature Tw2, the supply of the heating brine based on the temperature is not performed. Is suppressed.
[0029]
The description of the specific embodiment is finished above, but the present invention is not limited to the above-described embodiment. For example, the above embodiment is applied to an air conditioner composed of one outdoor unit and a plurality of indoor units. However, the above embodiment is applied to one unit of both units or a plurality of outdoor units. May be. The values of the predetermined temperature and the predetermined time can be arbitrarily changed, and the specific configuration of the apparatus and the control procedure can be appropriately changed without departing from the spirit of the present invention.
[0030]
【The invention's effect】
As described above, according to the refrigerant heating air conditioner of the present invention, when at least one of the inlet side water temperature and the outlet side water temperature is equal to or lower than the first predetermined temperature and equal to or higher than the second predetermined temperature, the outdoor unit is stopped. Because the heated brine supply source is made to supply the heated brine to the water heat exchanger regardless of the inside , the water exposed to the outside air even when the operation of the air conditioner is stopped in the severe winter season etc. Freezing of brine in the piping can be completely prevented.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of an air conditioner according to an embodiment of the present invention.
FIG. 2 is a flowchart showing a procedure of a heating brine supply control subroutine.
FIG. 3 is a flowchart showing a procedure of a heating brine supply control subroutine.
[Explanation of symbols]
1 outdoor unit 3a, 3b indoor unit 11 water heat exchanger 17 outdoor ECU
45 Inlet side water temperature sensor 47 Outlet side water temperature sensor 71, 73 Water pipe 75 Boiler

Claims (2)

An outdoor unit having a water heat exchanger and a compressor used for refrigerant heating, an indoor unit connected to the outdoor unit via a refrigerant circuit, and a heating brine supply for supplying heating brine to the water heat exchanger A refrigerant heating air conditioner comprising: a source; an inlet side water temperature sensor that detects an inlet side water temperature of the water heat exchanger; and an outlet side water temperature sensor that detects an outlet side water temperature of the water heat exchanger.
While the compressor is stopped, the inlet side water temperature and the outlet side water temperature are detected at predetermined time intervals, and at least one of the inlet side water temperature and the outlet side water temperature is equal to or lower than a first predetermined temperature and a second predetermined temperature. A refrigerant heating air conditioner comprising heating brine supply control means for operating the heating brine supply source and heating the brine to be circulated to the water heat exchanger when the temperature is equal to or higher than the temperature. An outdoor unit having a water heat exchanger and a compressor for heating the refrigerant, an indoor unit connected to the outdoor unit via a refrigerant circuit, and a heating brine supply for supplying heating brine to the water heat exchanger A refrigerant heating air conditioner comprising: a source; an inlet side water temperature sensor that detects an inlet side water temperature of the water heat exchanger; and an outlet side water temperature sensor that detects an outlet side water temperature of the water heat exchanger.
While the compressor is stopped, the inlet side water temperature and the outlet side water temperature are detected at predetermined time intervals, and at least one of the inlet side water temperature and the outlet side water temperature is equal to or lower than a first predetermined temperature and a second When the temperature is equal to or higher than a predetermined temperature, the heating brine supply source is operated to heat the brine to be circulated to the water heat exchanger, and at least one of the inlet side hot water and the outlet side hot water has a third predetermined temperature at a predetermined time. The refrigerant-heated air is provided with heating brine supply control means for stopping the heating brine supply source and stopping the supply of the heating brine regardless of the operation status of the outdoor unit. Harmony machine.

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