JP3534968B2 - Refrigerant heating air conditioner - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerant heating type air conditioner which is provided with a refrigerant heating device for heating a refrigerant during heating and performs a refrigerant recovery operation at the start of heating operation.

[0002]

2. Description of the Related Art In a refrigerating cycle of an air conditioner for heating or cooling a room, heat of combustion is used as a heat source instead of using heat absorbed in an outdoor heat exchanger, which is an evaporator during heating, as a heat source. There is a refrigerant heating type. This refrigerant heating type air conditioner has an advantage that the heating capacity does not depend on the outside air temperature unlike the heat pump type that uses the atmosphere as a heat source, and the heating capacity according to the combustion amount can be exhibited even at a low outside air temperature. .

When the heating operation of the refrigerant heating type air conditioner is started, since the outdoor heat exchanger is not used, the refrigerant recovery operation for recovering the refrigerant existing in the outdoor heat exchanger is performed. With this refrigerant recovery operation, a constant amount of refrigerant can be maintained during the refrigeration cycle during heating operation. Conventionally, this refrigerant recovery operation has been performed for a certain period of time since the start of heating operation.

The conventional refrigerant heating type air conditioner will be described below with reference to the drawings. 8 and 9
Shows a refrigeration cycle unit and control operation diagram of an air conditioner equipped with a conventional refrigerant heating device. In FIG. 8, 1
Is a variable capacity (frequency) type compressor, 2 is a two-way valve for allowing the refrigerant to flow, 3 is an indoor heat exchanger on the use side, 4 is a two-way valve for allowing the refrigerant to flow to the heating apparatus for heating the heating, and 5 is Refrigerant heating device which is a heat source for heating, 6 is an outdoor heat exchanger for cooling, 7 is a first check valve for stopping the flow of refrigerant during heating, 8 is a decompressor for cooling, and 9 is a flow of refrigerant during heating. It is the second check valve to stop.

In the air conditioner equipped with the refrigerant heating device configured as described above, when cooling is selected after the operation described with reference to FIG. 9, the four-way valve 2 is turned on and the compressor 1 is turned on. Refrigerant flows in the direction of the dashed arrow of
The indoor heat exchanger 3 on the use side has a low temperature and a low pressure and can be cooled, and the cooling operation is performed until a stop command is input. When heating is selected, the refrigerant collected in the outdoor heat exchanger 6 is recovered in the heating cycle. This is because the outdoor heat exchanger 6 is connected to the suction side of the compressor 1 by turning off the four-way valve 2 and the two-way valve 4, and the compressor 1 is turned on to move the refrigerant to the indoor heat exchanger 3. The refrigerant is prevented from accumulating in the outdoor heat exchanger 6 which is not used during the heating operation. Next, after the set time has elapsed, the recovery of the refrigerant is completed, the two-way valve 4 is opened, the refrigerant is allowed to flow to the refrigerant heating device 5, and the combustion is turned on, so that the indoor heat exchanger 3 becomes high temperature and high pressure, and heating operation becomes possible. . Next time a stop command is input,
The compressor 1, the combustion, and the two-way valve 4 are turned off, and the heating operation ends.

As another conventional example, a pressure gauge and a two-way valve are installed between the outdoor heat exchanger and the four-way valve, and the pressure is set to a set pressure (0
It has been proposed that the refrigerant recovery operation is performed until the pressure becomes lower than the set pressure if the pressure is higher than kg / cm ² ) and the heating operation is started without the refrigerant recovery operation if the pressure is lower than the atmospheric pressure (Japanese Patent Laid-Open No. 1-1455).
3 gazette).

[0007]

However, the following problems have been encountered in the refrigerant recovery operation of the above-described conventional refrigerant heating type air conditioner. That is, in order to maintain a constant amount of refrigerant during the refrigeration cycle during heating operation, the time required to recover the maximum retention amount of the refrigerant in response to a request from the outdoor heat exchanger 6 in which the refrigerant accumulates at low temperatures. Will be set as the refrigerant recovery operation time. When the refrigerant recovery operation is performed for an unnecessarily long time, there is no refrigerant to be recovered, the suction pressure of the compressor 1 becomes equal to or lower than the atmospheric pressure, and sliding occurs due to the thermal stress due to the temperature difference between the low temperature suction section inside the cylinder of the compressor 1. It becomes a problem in the reliability of the part. In particular, when the refrigerant recovery operation time is set to a constant value assuming a cold stagnation operation, the refrigerant stagnation amount is small when the operation is resumed after a short stop, and the state below the atmospheric pressure of the compressor 1 is long. There was a drawback that

Further, the lengthening of the refrigerant recovery operation delays the start of the heating operation, delays the blowing of warm air, and lengthens the time required to reach the indoor set temperature, which causes a problem in terms of comfort. . On the other hand, on the contrary, when the refrigerant recovery time is short, the amount of refrigerant required for heating operation is insufficient, and the refrigerant heating device 5
There is a problem that normal heating cannot be performed due to a phenomenon such as an abnormal rise in the temperature of.

In the other conventional example, since the pressure gauge is used, the cost is relatively high, and the cost is further increased if the pressure sensor used for other control is used. Therefore, in view of the above problems, an object of the present invention is a refrigerant heating type that can improve the reliability and comfort of the compressor with an inexpensive structure without complicating the structure of the refrigeration cycle. An object is to provide an air conditioner.

[0010]

In order to solve the above problems, a refrigerant heating type air conditioner according to claim 1 of the present invention comprises a variable capacity compressor, a four-way valve, an indoor heat exchanger, a pressure reducer, and The check valve of No. 1 and the outdoor heat exchanger are connected in an annular shape, and the refrigerant heating device is connected to the suction side of the compressor from between the indoor heat exchanger and the decompressor via a two-way valve to form a refrigeration cycle. Comparing the compressor intake temperature detecting means for detecting the compressor intake temperature, the temperature setting part for storing the set temperature, and the compressor intake temperature detected by the compressor intake temperature detecting means and the set temperature of the temperature setting part When the compressor suction temperature detected by the compressor suction temperature detecting means becomes equal to or lower than the set temperature during the refrigerant recovery operation in which the two-way valve is closed, the means and the time measuring means for storing the set time are provided. After the time of the time measuring means has elapsed, the refrigerant recovery operation ends It is also provided with a control means for opening control of the two-way valve so that.

As described above, the refrigerant recovery operation is terminated after the time of the time measuring means has elapsed from the time when the compressor intake temperature detected by the compressor intake temperature detecting means becomes lower than the set temperature during the refrigerant recovery operation. Therefore, the operation in which the suction pressure of the compressor falls below the atmospheric pressure is eliminated, and the reliability of the compressor can be improved. Further, when the refrigerant recovery operation is completed, the two-way valve is opened by the control means and the refrigerant is heated by the refrigerant heating device to enable the heating operation. In this way, the refrigerant recovery operation can be shortened while maintaining the amount of refrigerant required for heating operation, so the time from the start of heating operation to the blowing of warm air can be shortened, and the set temperature can be reached faster, improving comfort. Can be planned.

According to a second aspect of the present invention, there is provided a refrigerant heating type air conditioner in which a variable capacity compressor, a four-way valve, an indoor heat exchanger, a pressure reducer, a first check valve, and an outdoor heat exchanger are connected in an annular shape. A refrigerant suction device is connected between the indoor heat exchanger and the pressure reducer to the suction side of the compressor via a two-way valve to form a refrigeration cycle, and compressor suction temperature detection means for detecting the compressor suction temperature, A storage means for storing the detected compressor suction temperature, a comparison means for comparing the previously detected compressor suction temperature by the storage means with the detected compressor suction temperature, and a clock means for storing the set time. Provided, the refrigerant recovery operation ends after the time of the time measuring means has elapsed from the time when the time change of the compressor intake temperature detected by the compressor intake temperature detection means changed from decreasing to increasing during the refrigerant recovery operation with the two-way valve closed. To open the two-way valve to control Those digits.

As described above, the refrigerant recovery operation is terminated after the time of the time measuring means has elapsed from the time when the time change of the compressor intake temperature detected by the compressor intake temperature detection means changes from decrease to increase during the refrigerant recovery operation. As a result, the operation in which the suction pressure of the compressor falls below the atmospheric pressure is eliminated, and the reliability of the compressor can be improved. Moreover, since the refrigerant recovery time is determined by the change in the compressor suction temperature, it is not necessary to set a specific compressor suction temperature, and the specification can be easily determined. Further, when the refrigerant recovery operation is completed, the two-way valve is opened by the control means and the refrigerant is heated by the refrigerant heating device to enable the heating operation. In this way, the refrigerant recovery operation can be shortened while maintaining the amount of refrigerant required for heating operation, so the time from the start of heating operation to the blowing of warm air can be shortened, and the set temperature can be reached faster, improving comfort. Can be planned.

A refrigerant heating type air conditioner according to a third aspect of the present invention is, in the first or second aspect, provided with compressor capacity control means for controlling so as to reduce the capacity of the compressor as the refrigerant recovery operation time elapses. It is a thing. As a result, it is possible to improve the reliability of the compressor by reducing the load on the sliding portion that is susceptible to thermal stress due to the temperature difference between the low suction temperature of the compressor vane and the compressor temperature.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION A refrigerant heating type air conditioner according to a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a refrigeration cycle diagram in a refrigerant heating type air conditioner of a first embodiment of the present invention. This refrigeration cycle consists of a variable capacity (frequency) type compressor 1, a four-way valve 2,
The indoor heat exchanger 3, the decompressor 8, the first check valve 7, the outdoor heat exchanger 6, and the second check valve 9 are annularly connected, and the outdoor heat exchanger 6 and the second check valve are connected. The above-mentioned four-way valve 2 is disposed between 9 and the flow of the refrigerant can be switched between the indoor heat exchanger 3 and the outdoor heat exchanger 6 by means of this four-way valve 2, and between the indoor heat exchanger 3 and the decompressor 8. A refrigerant heating device 5 is connected between the compressor 1 and the second check valve 9 via a two-way valve 4. The above configuration is similar to that of the conventional example, and the same parts are denoted by the same reference numerals. Here, the flow of the refrigerant during the heating operation is indicated by a solid line, and the flow of the refrigerant during the cooling operation is indicated by a broken line.

Further, in FIG. 1, 10 is a suction temperature thermistor (compressor suction temperature detecting means) of the compressor. The compressor suction temperature thermistor 10 detects the compressor suction temperature when the refrigerant recovery operation is performed by controlling the two-way valve 4 to be closed. Then, the control means is provided for controlling the opening of the two-way valve so that the refrigerant recovery operation is terminated after the time of the time measuring means has elapsed from the time when the compressor suction temperature becomes equal to or lower than the set temperature.

FIG. 2 is a schematic block diagram of the control means (control circuit). This figure shows a microcomputer (microcomputer) 11
A heating start signal and a signal from the compressor intake temperature thermistor 10 are input to the control circuit equipped with. The heating activation signal here may be a signal from the indoor unit, the outdoor unit, or the switch 18. Further, the microcomputer 11 has a temperature setting unit for storing the set temperature, and a comparing unit 12 for comparing the compressor intake temperature detected by the compressor intake temperature thermistor 10 with the set temperature of the temperature setting unit, and the set time. Memorizing timing means are provided.

The output of this control circuit outputs a signal from the microcomputer 11 to drive the variable displacement compressor 1.
There are three. Further, a signal can be output from the microcomputer 11 to energize the relay coil 17 of the two-way valve 4 to turn on the contact 17a to turn on (open) the two-way valve 4. Furthermore, 15
Is a power supply, 14 is an amplifier, and 16 is a power switch. Next, the operation of the refrigerant heating type air conditioner configured as described above will be described based on the control operation diagram of FIG.

The outdoor microcomputer 11 receives the heating operation start signal from the switch 18 and starts the heating operation. Next, the refrigerant recovery operation is started, and the variable capacity compressor 1 is operated at the set operation frequency while the two-way valve 4 remains OFF (closed).
As a result, the piping path from the first check valve 7 to the suction of the compressor 1 and the refrigerant of the outdoor heat exchanger 6 are collected in the discharge piping path of the compressor 1 (mainly the indoor heat exchanger 3). At this time, the suction temperature t is detected by the compressor suction temperature thermistor 10 and compared with the temperature t ₁ set by the temperature setting unit. The refrigerant recovery operation is stopped and the two-way valve 4 is controlled in the opening direction after the time T0 has elapsed from the time when the suction temperature t becomes equal to or lower than the set temperature t ₁ . After that, by flowing the refrigerant to the refrigerant heating device 5 and turning on the combustion of the refrigerant heating device 5, the indoor heat exchanger 3 becomes high temperature and high pressure, and the heating operation becomes possible. Next, when a stop command is input, the compressor 1, the refrigerant heating device 5, and the two-way valve 4 are turned off, and the heating operation ends.

In the refrigerant recovery operation, the refrigerant circulation amount decreases as the recovery time elapses, so the heat absorption capacity decreases, and the suction portion of the compressor 1 does not become a heating state, and the suction temperature thermistor 1
At 0, a temperature close to the saturation temperature corresponding to the suction pressure can be measured. This suction temperature of the compressor is set according to the operation characteristics of the refrigerant heating type air conditioner, and the refrigerant recovery operation is terminated after a lapse of time at the second unit level, so that the suction pressure of the compressor 1 is equal to or lower than the atmospheric pressure. Therefore, the reliability of the compressor 1 can be improved. Further, since the refrigerant recovery operation can be shortened, the time from the start of the heating operation to the blowing of warm air can be shortened, and the set temperature can be reached sooner to improve comfort.

In this embodiment, the time count T0
After the lapse of time, the refrigerant recovery operation is stopped, but the time counting time may be set to zero by setting the compressor suction temperature optimally. A refrigerant heating type air conditioner according to a second embodiment of the present invention will be described with reference to FIGS. 4 and 5. Compared to the first embodiment, the schematic configuration diagram of the refrigeration cycle and the control circuit in this embodiment is provided with a storage means for storing the compressor suction temperature instead of the temperature setting section, and the comparison means stores The compressor suction temperature t _n-1 previously detected by the means and the detected compressor suction temperature t _n are compared. Other configurations are similar to those of the first embodiment.

Next, the operation of the refrigerant heating type air conditioner will be described with reference to the control operation diagram of FIG. First
In the same manner as in the embodiment of FIG.
By operating the variable displacement compressor 1 at a set operating frequency until OFF, the piping path from the first check valve 7 to the suction of the compressor 1 and the refrigerant in the outdoor heat exchanger 6 are compressed by the compressor. It is collected in the first discharge pipe path (mainly the indoor heat exchanger 3). At this time, the suction temperature t _n is detected by the compressor suction temperature thermistor 10, and the previously detected compressor suction temperature and the suction temperature detected this time are compared. Then, the refrigerant recovery operation is stopped and the two-way valve 4 is controlled in the opening direction after the lapse of the time T0 from the time when the previously detected suction temperature t _n-1 becomes equal to or lower than the suction temperature t _n .

As shown in FIG. 5, the time-dependent change in the compressor suction temperature varies with the passage of time after the compressor is stopped, but shows a minimum value and then a rising tendency. If enough time has passed after the compressor has stopped (when it is cold), the temperature of the refrigerant heater will also drop to near ambient temperature. The refrigerant dissolved in the compressor oil evaporates, causing a slight temperature rise. Similarly, when the compressor 1 has stopped and only a short time has passed (when it is hot), it similarly drops sharply to the minimum value after the start of the refrigerant recovery operation, but the residual heat of the refrigerant heating device 5 causes heat transfer and compression in the refrigeration cycle. Evaporation of the refrigerant dissolved in the machine oil causes a remarkable temperature rise.

Since such a temperature change is detected by the compressor intake temperature thermistor 10 to determine the refrigerant recovery operation time, it is not necessary to set a specific compressor intake temperature, and the specification can be easily determined. Further, the operation in which the suction pressure of the compressor 1 becomes equal to or lower than the atmospheric pressure is eliminated, and the reliability of the compressor 1 can be improved. Further, since the refrigerant recovery operation can be shortened, the time from the start of the heating operation to the blowing of warm air can be shortened, and the set temperature can be reached sooner to improve comfort.

In this embodiment, the time count T0
After the lapse of time, the refrigerant recovery operation is stopped, but the time counting time may be set to zero by setting the condition of t _n ≧ t _n−1 multiple times in the compressor suction temperature comparison means. Third of this invention
The refrigerant heating type air conditioner of the embodiment will be described with reference to FIGS. 6 and 7. The schematic configuration diagram of the refrigeration cycle and the control circuit in this embodiment is the first or second
In the embodiment of the present invention, a compressor capacity control means for controlling the capacity of the compressor to gradually decrease with the passage of the refrigerant recovery operation time is provided. Specifically, the compressor capacity control means provided in the second embodiment compares the compressor suction temperature t _n-1 previously detected by the compressor suction temperature thermistor 10 with the suction temperature t _n detected this time. If the previously detected suction temperature t _n-1 is not low, the operating frequency of the variable displacement compressor 1 is lowered in minute steps such as Hz ₁ , Hz _2, ... Hz _n .

FIG. 7 shows the change characteristics of the suction temperature and the operating frequency of the compressor. When the operating frequency of the compressor 1 is lowered in small steps, and if the previously detected intake temperature t _n-1 is lower than the presently detected intake temperature t _n , after the elapsed time T0,
The refrigerant recovery operation is stopped and the two-way valve 4 is controlled in the opening direction. As a result, the piping path from the first check valve 7 to the suction of the compressor 1 and the refrigerant in the outdoor heat exchanger 6 are recovered in the discharge piping path of the compressor 1 (mainly the heat exchanger 3).

As described above, since the operating frequency of the compressor 1 is decreased in minute steps as the refrigerant recovery operation elapses, thermal stress is applied due to the temperature difference between the low intake temperature of the compressor vane and the compressor temperature. It is possible to reduce the load on the easily sliding portion and improve the reliability of the compressor 1. Although the same effect can be obtained by providing the compressor capacity control means in the first embodiment, the compressor capacity control means in this case detects the suction temperature t by the compressor suction temperature thermistor 10 and If the suction temperature t is not lower than the set temperature t _{1 as} compared with the temperature t ₁ set in the setting unit, the operating frequency of the variable displacement compressor 1 is similarly lowered in minute steps. .

Further, in the present embodiment, the step of uniformly reducing the compressor operating frequency is provided in minute steps, but a time interval of lowering may be set. Further, the same effect can be obtained by providing the step of decreasing the compressor operating frequency according to the decrease of the compressor suction temperature.

[0029]

According to the refrigerant heating type air conditioner of the present invention, from the time when the compressor suction temperature detected by the compressor suction temperature detection means becomes equal to or lower than the set temperature during the refrigerant recovery operation. Since the refrigerant recovery operation is terminated after the time of the time measuring means has elapsed, the operation in which the suction pressure of the compressor becomes equal to or lower than the atmospheric pressure is eliminated, and the reliability of the compressor can be improved. Further, when the refrigerant recovery operation is completed, the two-way valve is opened by the control means and the refrigerant is heated by the refrigerant heating device to enable the heating operation. In this way, the refrigerant recovery operation can be shortened while maintaining the amount of refrigerant required for heating operation, so the time from the start of heating operation to the blowing of warm air can be shortened, and the set temperature can be reached faster, improving comfort. Can be planned.

According to the refrigerant heating type air conditioner of the second aspect of the present invention, at the time when the time change of the compressor suction temperature detected by the compressor suction temperature detecting means during the refrigerant recovery operation changes from decrease to increase. Since the refrigerant recovery operation is ended after the time of the time measuring means has elapsed, the operation in which the suction pressure of the compressor becomes equal to or lower than the atmospheric pressure is eliminated, and the reliability of the compressor can be improved. Moreover, since the refrigerant recovery time is determined by the change in the compressor suction temperature, it is not necessary to set a specific compressor suction temperature, and the specification can be easily determined. Further, when the refrigerant recovery operation is completed, the two-way valve is opened by the control means and the refrigerant is heated by the refrigerant heating device to enable the heating operation. In this way, the refrigerant recovery operation can be shortened while maintaining the amount of refrigerant required for heating operation, so the time from the start of heating operation to the blowing of warm air can be shortened, and the set temperature can be reached faster, improving comfort. Can be planned.

According to the third aspect of the present invention, since the compressor capacity control means for controlling the capacity of the compressor to decrease with the passage of the refrigerant recovery operation time is provided, the low intake temperature of the compressor vane and the like and the compressor temperature are controlled. It is possible to improve the reliability of the compressor by reducing the load on the sliding portion that is susceptible to thermal stress due to the temperature difference.

[Brief description of drawings]

FIG. 1 is a refrigeration cycle diagram of a refrigerant heating type air conditioner according to a first embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of a control circuit according to the first embodiment.

FIG. 3 is a control operation diagram according to the first embodiment.

FIG. 4 is a control operation diagram of a refrigerant heating type air conditioner according to a second embodiment of the present invention.

FIG. 5 is a graph showing a change over time of a compressor suction temperature in the second embodiment.

FIG. 6 is a control operation diagram of a refrigerant heating type air conditioner according to a third embodiment of the present invention.

FIG. 7 is a graph showing the change characteristics of the suction temperature and the operating frequency of the compressor in the third embodiment.

FIG. 8 is a refrigeration cycle diagram of a conventional refrigerant heating type air conditioner.

FIG. 9 is a control operation diagram of a conventional refrigerant heating type air conditioner.

[Explanation of symbols]

1 Capacity (frequency) variable type compressor 2 four-way valve 3 Indoor heat exchanger 4 two-way valve 5 Refrigerant heating device 6 outdoor heat exchanger 7 First check valve 8 Cooling decompressor 9 Second check valve 10 Compressor suction temperature thermistor 11 Outdoor microcomputer

─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Takahiko Ao 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) References JP-A-3-95360 (JP, A) JP-A-7- 190531 (JP, A) JP-A-1-314866 (JP, A) Actual development 56-47451 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) F25B 13/00

Claims (3)

(57) [Claims] 1. A variable capacity compressor, a four-way valve, an indoor heat exchanger, a pressure reducer, a first check valve, and an outdoor heat exchanger are annularly connected, and between the indoor heat exchanger and the pressure reducer. To a suction side of the compressor through a two-way valve to connect a refrigerant heating device to form a refrigeration cycle, a compressor suction temperature detecting means for detecting the compressor suction temperature, and a temperature setting section for storing the set temperature. When,
Comparing means for comparing the compressor suction temperature detected by the compressor suction temperature detecting means with the set temperature of the temperature setting section, and a time measuring means for storing the set time are provided, and the two-way valve is closed. During the refrigerant recovery operation, the two-way valve is opened to terminate the refrigerant recovery operation after the time of the time measuring means elapses from the time when the compressor intake temperature detected by the compressor intake temperature detection means becomes equal to or lower than the set temperature. A refrigerant heating type air conditioner comprising a control means for controlling. 2. A variable capacity compressor, a four-way valve, an indoor heat exchanger, a pressure reducer, a first check valve, and an outdoor heat exchanger are annularly connected, and between the indoor heat exchanger and the pressure reducer. To a suction side of the compressor via a two-way valve to connect a refrigerant heating device to form a refrigeration cycle, and a compressor suction temperature detecting means for detecting the compressor suction temperature and the detected compressor suction temperature are stored. Storage means, a comparison means for comparing the compressor suction temperature detected previously by the storage means with the detected compressor suction temperature, and a clock means for storing the set time, and the two-way valve is closed. During the refrigerant recovery operation, the refrigerant recovery operation is terminated so that the refrigerant recovery operation is terminated after a lapse of time of the time measuring means from the time when the time change of the compressor intake temperature detected by the compressor intake temperature detection means changes from decrease to increase. The provision of control means for controlling the opening of the one-way valve Characteristic refrigerant heating type air conditioner. 3. The refrigerant heating type air conditioner according to claim 1, further comprising compressor capacity control means for controlling the capacity of the compressor to decrease with the passage of the refrigerant recovery operation time.