JPH0612477Y2 - Refrigeration equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a refrigerating device that switches, for example, from heating to defrosting based on the detection result of the heat source side heat exchanger temperature.

(Prior Art) As a conventional example of the above refrigerating apparatus, for example,
The device described in JP-A-54-140344 can be mentioned. In the above device, during the heating operation in which the refrigerant discharged from the compressor is circulated from the use side heat exchanger to the heat source side heat exchanger, when frost occurs in the heat source side heat exchanger, the outside temperature Since the temperature difference obtained by subtracting this heat source side heat exchanger temperature increases with the increase in the amount of frost, it is designed to switch to the defrosting operation when the temperature difference exceeds the reference temperature difference. There is. Further, the temperature of the heat source side heat exchanger rises due to the completion of defrosting, and when the temperature exceeds the reference temperature, the defrosting operation is automatically returned to the heating operation.

(Problems to be solved by the invention) By the way, in recent years, an indoor heat exchanger as a usage-side heat exchanger is provided in one outdoor unit that internally houses an outdoor heat exchanger as a heat source-side heat exchanger and a compressor. A multi-type air conditioner, which is configured by connecting a plurality of indoor units respectively installed in parallel with each other, has been put into practical use. As an outdoor heat exchanger in such an air conditioner, it is necessary to have a large heat exchange capacity commensurate with the total heat exchange capacity of each indoor heat exchanger. Therefore, a large outdoor heat exchanger is also used in terms of shape. ing. And, in such an outdoor heat exchanger, in order to reduce the occupied floor area, the height is made large and the thickness is made thin, and a plurality of parallel pipe paths are provided inside the inlet,
It is also designed to improve the heat exchange efficiency as a configuration in which the refrigerant is split and merged at the outlet.

However, in the outdoor heat exchanger as described above, a large uneven flow is likely to occur due to, for example, the pressure difference of the circulating refrigerant in the height direction, and thus, for example, to cause a positional difference in the defrosting speed, When determining the completion of defrosting with a temperature sensor attached to a pipe path with a large refrigerant flow rate, there is a problem such as switching to heating operation with unmelted residue left on the pipe path with a small refrigerant flow rate. Has become. Also, while monitoring the condensation pressure during cooling operation at the temperature of the outdoor heat exchanger described above, when operating while preventing the occurrence of abnormally high pressure, it is not possible to fully grasp the temperature state of the entire outdoor heat exchanger. However, there was also a problem that the response in the event of an abnormality was delayed.

The present invention has been made in view of the above, and an object thereof is to provide a refrigeration apparatus capable of more accurately grasping a temperature state in a large heat source side heat exchanger, and thus performing more appropriate operation. is there.

(Means for Solving the Problem) Therefore, as shown in FIG. 1, in the refrigerating apparatus according to the first aspect of the present invention, the heat source side heat exchanger 12 and the use side heat exchanger 20 are provided in the compressor 1. Are connected to each other via a four-way switching valve 9 so as to be able to circulate the refrigerant, and temperature sensors 35, 35 for detecting the temperature of the heat source side heat exchanger 12 are provided at a plurality of different positions in the heat source side heat exchanger 12. And the operation control means 45 for controlling the operation based on the respective detected temperatures of the temperature sensors 35, 35, and further in the cooling operation mode from the respective detected temperatures of the plurality of temperature sensors 35, 35. Is the maximum temperature, the average temperature in the heating operation mode, and the minimum temperature in the defrosting operation mode. The operation control means 45 has a heat source side heat exchanger temperature determining means 50. It is a sign.

(Operation) In the refrigeration apparatus according to the first aspect, the temperature sensors 35, 35 detect temperatures at a plurality of different positions in the heat source side heat exchanger 12, so that the heat source side heat exchanger 12 is large. It is possible to grasp a more accurate temperature state in the case of forming a temperature difference locally, and in order to detect an abnormally high pressure during cooling operation, the temperature sensors 35, 35 described above are used.
By monitoring the highest temperature among the detected temperatures in, it is possible to quickly respond when an abnormality occurs. In addition, by starting and ending the defrosting operation based on the lowest temperature among the above detected temperatures, it is possible to prevent the excessive frosting amount locally, and to perform defrosting quickly. It is possible to return to the heating operation without being left unmelted. Further, during heating operation, the temperature of the heat source side heat exchanger 12 is detected as a refrigerant evaporation temperature, and based on the detected temperature, a liquid pipe connecting the heat source side heat exchanger 12 and the use side heat exchanger 20 to each other. In the case where the degree of superheat control of the electric expansion valve provided in the above is performed to automatically adjust the amount of the circulating refrigerant, the average temperature of the temperatures detected by the temperature sensors 35, 35 is calculated to perform the above operation. Operation that better matches the heat exchange capacity of the side heat exchanger 12 can be maintained.

(Embodiment) Next, a concrete embodiment of the refrigerating apparatus of the present invention will be described in detail with reference to the drawings.

FIG. 2 is a refrigerant circuit diagram of a refrigerating machine in one embodiment of the present invention in which the first to fourth indoor units A to D are connected to one outdoor unit X to constitute a multi-type air conditioner. Shows.

The compressor 1 is installed in the outdoor unit X,
This compressor 1 is a so-called two-inverter in which a first compressor 2 of variable rotational speed controlled by an inverter and a second compressor 3 of constant rotational speed are connected in parallel to each other and housed in a housing. The first and second compressors 2 and 3 are respectively provided on their suction sides with a first accumulator 4,
They are connected to each other via 5. And the compressor 1
The discharge pipe 6 and the suction pipe 8 provided with the second accumulator 7 are connected to a four-way switching valve 9, and the four-way switching valve 9 further includes a first gas pipe 10 and a second gas pipe 11 respectively.
And are connected. An outdoor heat exchanger (heat source side heat exchanger) 12 is connected to the first gas pipe 10, and a first electric expansion valve 13 and a liquid receiver 14 are sequentially provided in the outdoor heat exchanger 12. The liquid pipe 15 is further connected. The tip of the liquid pipe 15 has a second electric expansion valve 16 ...
6 is branched into four liquid branch pipes 17, ... 17 provided, and the tip of the second gas pipe 11 is also provided with the gas branch pipe mufflers 18 ,. It is also branched into four gas branch pipes 19 ... And these liquid branch pipes 17 ... 17 and gas branch pipes 19 ... 19
And the indoor heat exchangers 20 (only the first indoor unit A is shown) 20 installed in the first to fourth indoor units A to D are respectively connected as use-side heat exchangers to circulate the refrigerant. The circuit is configured.

In the discharge pipe 6, a discharge pipe muffler 21 and a first opening / closing valve 22 are sequentially provided from the compressor 1 side, and the pipe between the two 21 and 22 and the first electric expansion in the liquid pipe 15 are arranged. The valve 13 is connected to the outdoor heat exchanger 12 side by a first bypass pipe 24 provided with a second opening / closing valve 23. Further, the first gas pipe 10 and the suction pipe 8 are connected by a second bypass pipe 26 provided with a third opening / closing valve 25, and the discharge pipe 6 is connected to a midway portion of the second bypass pipe 26. A heat exchange section 28 is provided in a heat storage tank 27 that is provided around the heat storage tank 27. These first and second bypass pipes 24 and 26 form a refrigerant circulation path during a defrosting operation described later.

Further, the discharge pipe 6 and the suction pipe 8 are connected to each other by a fourth opening / closing valve 29.
Are connected to each other by a third bypass pipe 30 which is interposed therebetween. This is to quickly equalize the pressure inside the refrigerant circuit by opening the fourth on-off valve 29 after the operation of the compressor 1 is stopped. It is for doing. Further, the liquid branch pipe 17 to which the first indoor unit A is connected is connected to the first bypass pipe 24 by the fourth bypass pipe 32 provided in the fifth opening / closing valve 31, and the first indoor unit A is connected. A parallel circuit of a sixth on-off valve 33 and a check valve 34 is provided in the gas branch pipe 19 which is provided, and these are used, for example, as a drying room for clothes after washing in a changing room in an unused bathroom. , The connection of the drying unit for blowing hot air into the drying chamber
The indoor unit A is configured so that it can be connected. In this case, the opening / closing operation of the fifth and sixth opening / closing valves 31 and 33 is performed in order to perform the refrigerant circulation control different from that of the other indoor units BD to the drying unit. The details are omitted, and the first indoor unit A is connected to the following, therefore, the fifth opening / closing valve 31 is kept closed, the sixth opening / closing valve 33 is kept open, and the fourth pressure equalizing unit is used. The refrigerant circulation control during the cooling / heating operation performed by closing the opening / closing valve 29 will be described.

In the heating operation in the air conditioner having the above-described configuration, the four-way switching valve 9 is compressed to the switching position shown by the solid line in the figure, the first opening / closing valve 22 is opened, and the second and third opening / closing valves 23 and 25 are closed. By operating the machine 1 and causing the refrigerant discharged from the compressor 1 to flow from each indoor heat exchanger 20 serving as a condenser to the outdoor heat exchanger 12 serving as an evaporator, as indicated by a solid arrow in the figure. To do. In this case, the superheat degree control of the evaporated refrigerant is performed by the first electric expansion valve 13, and the second electric expansion valves 16 ,.
The refrigerant distribution amount to each indoor heat exchanger 20 is controlled by controlling the opening degree so that the condensed refrigerant temperatures at the outlets of the indoor heat exchangers 20 become the same temperature. It should be noted that the second electric expansion valve 16 corresponding to the indoor unit of the stop room has a predetermined stop opening degree (an opening degree capable of flowing a slight amount of refrigerant commensurate with natural heat dissipation in order to prevent liquid return to the compressor 1). ).

In the cooling operation, the four-way switching valve 9 is switched to the switching position shown by the broken line in the figure from the above, and the refrigerant discharged from the compressor 1 is transferred to the outdoor heat exchanger 12 serving as the condenser as shown by the broken line arrow in the figure.
To the respective indoor heat exchangers 20 ... At this time, the first electric expansion valve 1
3 is fully opened, and the second electric expansion valves 16 ... 16 control the degree of superheat of the refrigerant. The second electric expansion valve 16 corresponding to the indoor unit in the cooling stop room is fully closed.

The defrosting operation for removing the frost generated in the outdoor heat exchanger 12 during the above heating operation is performed by the second opening / closing valve 23 and the third opening / closing valve 2.
5 and 5 respectively, the first on-off valve 22 is closed, the four-way switching valve 9 is switched to the switching position shown by the broken line in the drawing, and the first and second electric expansion valves 13 and 16 are all closed. Close it.

Thereby, the high temperature gas refrigerant discharged from the compressor 1 is
As shown by the one-dot chain line arrow in FIG. 2, it is directly supplied to the outdoor heat exchanger 12 through the first bypass pipe 24,
Defrosting is performed by using the compression work in the compressor 1 as a defrosting heat source. The refrigerant that has passed through the outdoor heat exchanger 12 is
The heat is returned from the first gas pipe 10 to the compressor 1 through the second bypass pipe 26. At this time, the amount of heat stored in the heat storage tank 27 is added to the circulating refrigerant. That is, the amount of external heat dissipated from the discharge pipe 6 that is maintained at a high temperature state by the flow of the high-temperature discharged gas refrigerant from the compressor 1 is stored in the heat storage agent in the heat storage tank 27 during the heating operation, and this is stored. It is designed to be used as a heat source for defrosting. Therefore, the defrosting operation can be completed in a shorter time.

In order to control the degree of superheat during the cooling / heating operation, the refrigerant circuit includes first to fifth temperature sensors 3 including a thermistor.
5 to 39 are provided, and in order to detect the temperature of the outdoor heat exchanger 12 as the temperature of the evaporated refrigerant during the heating operation, the outdoor heat exchanger 12 has the first temperature at two different positions. Sensors 35, 35 are attached. That is, the outdoor heat exchanger 12 in the above-mentioned multi-type air conditioner needs a large heat exchanger capacity commensurate with the total heat exchange capacity of the four indoor heat exchangers 20.
For this reason, it is necessary to configure it as an outdoor heat exchanger that is also large in shape, but this is configured with a large height and a thin thickness in order to reduce the occupied floor area,
A plurality of parallel pipe paths are provided inside, and the refrigerant is split and merged at the inlet and the outlet to improve heat exchange efficiency. More specifically, eight parallel pipe paths each having four pipes per path are provided, and a total of 32 horizontally extending pipes are arranged vertically. The whole is divided into an upper side and a lower side, and two outdoor fans (not shown) are arranged adjacent to each other. In such a configuration, a drift is likely to occur due to the pressure difference of the circulating refrigerant in the height direction and the like, so that the temperature difference in the vertical direction becomes relatively large. Therefore, the first temperature sensors 35, 35 are attached to the bottom side pipes on the upper side and the lower side, respectively.

The second temperature sensor 36 for detecting the superheat temperature of the evaporative gas refrigerant returned from the outdoor heat exchanger 12 to the compressor 1 during the heating operation, and the indoor heat exchangers during the heating operation. Each of the third temperature sensors 37, ... 37 for detecting the temperature of the condensed refrigerant at the outlet of the 20 is connected to the indoor heat exchanger 20.
..20 are respectively attached to the liquid side connecting pipes that connect the liquid branch pipes 17 ,. On the other hand, the fourth temperature sensor 38 and the fifth temperature sensor 39 that detect the evaporative refrigerant temperature and the evaporative gas refrigerant superheat temperature during the cooling operation are respectively the indoor heat exchangers 20 ... 20 and the gas branch pipes 19 ... 19. Are attached to each. Further, a room temperature sensor 40 for detecting a room temperature is arranged in each of the indoor units A to D, and an outside air temperature sensor 41 for detecting a temperature of outside air near the outdoor heat exchanger 12 is arranged in the outdoor unit X, respectively. Has been done.

Next, regarding the control of the operation in the air conditioner,
This will be described with reference to the operation control system diagram in the figure.

As shown in the figure, each of the indoor units A to D has an indoor control device 43 (only the first indoor unit A is shown).
Each of the indoor control devices 43 is connected to the driving remote controller 44 and the room temperature sensor 40 and the fourth temperature sensor 38 described above. Each of the operation remote controllers 44 has an operation switch, a cooling / heating changeover switch, and a temperature setting switch for setting a desired room temperature. The operation switch is ON, and the room temperature detected by the room temperature sensor 40 is the room temperature. Is not reaching the set room temperature (when the indoor thermostat is ON), the heating operation request signal or the cooling operation request signal is sent from each indoor control device 43 to the outdoor unit X according to the switching position of the cooling / heating switch. The temperature difference ΔT between the room temperature detected by the room temperature sensor 40 and the set room temperature at this time, and the fourth temperature sensor 3
The detected temperature signal Te at 8 is also output.

On the other hand, the outdoor unit X is an outdoor control device (operation control means).
The outdoor control device 45 is provided with an operation request unit grasping section 46, a frequency control section 47, and a valve control section 48. The operation request unit grasping section 46 discriminates the indoor unit outputting the operation request signal for heating or cooling and outputs the operation unit signal to the frequency control section 47 and the valve control section 48. As a result, the frequency control unit 47 first sums the rated capacities of the indoor units that are requested to operate based on the operation unit signal, and the maximum temperature in the temperature difference signal ΔT from the indoor units that are requested to operate. The difference is extracted, and the initial frequency corresponding to the combination of the total rated capacity and the maximum temperature difference is selected from the initial frequency data table. Then, after the operation of the compressor 1 is started at this frequency and the number of revolutions corresponding to the initial frequency is reached, the load is changed by PID control, for example, in accordance with the subsequent change in the total value of the temperature difference signal ΔT. The operating frequency corresponding to the above is sequentially generated, and the compressor 1 is operated at this frequency. When the number of operating rooms on the indoor side increases or decreases, the control is repeated from the control for newly selecting the initial frequency in the above procedure. When the above operating frequency exceeds the upper limit of the variable frequency range of the first compressor 2, the second compressor 3 is started and the frequency of the power supply applied to the second compressor 3 (for example, commercial frequency). The frequency obtained by subtracting (60 Hz) from the operating frequency is output to the inverter control device 49, and the first compressor 2 is operated at this frequency.

On the other hand, in the valve control unit 48, switching of the four-way switching valve 9 according to a heating or cooling operation request, opening / closing control of the first to third opening / closing valves 22, 23, 25, and first and second electric expansion. The opening degree of the valves 13 and 16 is controlled. During heating operation, the detected superheat degree obtained by subtracting the outdoor heat exchanger temperature from the temperature detected by the second temperature sensor 36, and during cooling operation,
The temperature detected by the fifth temperature sensor 39 and the fourth temperature sensor 38
In order to maintain the detected superheat degree obtained by the difference from the detected temperature Te at the reference superheat degree, the first electric expansion valve 1
3. The opening degree of the second electric expansion valve 16 ... 16 is controlled.

By the way, the temperature of the outdoor heat exchanger is detected by the two first temperature sensors 35, 35 as described above, and the respective detected temperatures are further provided in the outdoor control device 45. It is input to the respective temperature monitoring units (heat source side heat exchanger temperature determining means) 50. When the operation unit signal corresponding to the heating operation request signal is input from the operation request unit grasping section 46 to the temperature monitoring section 50, the average temperature of the detected temperatures is calculated as the temperature monitoring section 5
0 is calculated, and this is output to the valve control unit 48 as the outdoor heat exchanger temperature. Therefore, the superheat control at the time of heating is performed based on the average temperature of the outdoor heat exchanger 12, and even if there is a local difference in the heat exchange state in the outdoor heat exchanger 12, the total heat The superheat degree control more suited to the exchange capacity will be performed.

Further, at the time of heating operation, in the temperature monitoring unit 50,
The lowest temperature among the temperatures detected by the first temperature sensors 35, 35 is extracted, and the temperature difference obtained by subtracting this temperature from the outside air temperature detected by the outside air temperature sensor 41 is compared with the defrosting start reference temperature difference. It is also made to do. When the temperature difference becomes smaller than the defrosting start reference temperature difference, the defrosting start signal is output to the frequency control unit 47 and the valve control unit 48. As a result, the switching to the defrosting operation described above is performed, and the defrosting operation is started. By thus starting defrosting based on the minimum temperature in the outdoor heat exchanger 12, the defrosting operation can be switched earlier without causing an excessive amount of frost formation, so that the defrosting operation can be performed more reliably in a shorter time. Defrosting can be performed.

Further, at the time of the defrosting operation, in the temperature monitoring unit 50, similarly to the above, the lowest temperature among the temperatures detected by the first temperature sensors 35, 35 is compared with the defrosting completion reference temperature,
When the defrosting completion reference temperature is exceeded, a defrosting completion signal is output to the frequency controller 47 and the valve controller 48. As a result, by performing the defrosting operation based on the minimum temperature in the outdoor heat exchanger 12, the defrosting operation with no unmelted residue is performed.

On the other hand, the operation monitoring unit grasping unit 4 is added to the temperature monitoring unit 50.
When the operation unit signal corresponding to the cooling operation request signal is input from 6, the highest temperature among the temperatures detected by the first temperature sensors 35, 35 is extracted, and this temperature is set as the high pressure regulation reference temperature. Monitor to compare. When this reference temperature is exceeded, a high voltage abnormality signal is output to the frequency control unit 47. As a result, the frequency control unit 47 performs control to gradually reduce the compression capacity of the compressor 1, and thereby the operation in which the increase in high pressure is suppressed is performed. In this way, by monitoring the high pressure based on the maximum temperature detected by the outdoor heat exchanger 12, it is possible to perform a quick control while suppressing an excessive increase in pressure.

In addition, although the case where two temperature sensors 35, 35 are provided in the outdoor heat exchanger 12 has been described above, the same operation as above can be performed when more temperature sensors are provided. Further, in the above description, a multi-type air conditioner in which a plurality of indoor units A to D are connected has been described as an example, but also in an air conditioner in which one indoor unit is connected and a refrigeration device other than the air conditioner. The present invention can be applied and configured.

(Effect of the Invention) As described above, in the refrigerating apparatus according to the first aspect of the present invention, the heat source side heat exchanger is operated based on the detected temperature at a plurality of different positions. Even when the size of the exchanger becomes large and a local temperature difference occurs, more appropriate operation based on a more accurate temperature state can be maintained. That is, by monitoring the maximum temperature among the detected temperatures during the cooling operation, it is possible to quickly respond to abnormally high pressure. In addition, by starting and ending the defrosting operation based on the lowest temperature among the above detected temperatures, it is possible to prevent the excessive frosting amount locally, and to perform defrosting quickly. It is possible to return to the heating operation without being left unmelted. Furthermore, by performing the superheat control during the heating operation based on the average temperature of the detected temperatures, it is possible to maintain the operation that is more suitable for the heat exchange capacity of the heat exchanger on the heat source side.

[Brief description of drawings]

FIG. 1 is a functional block diagram of the present invention, FIG. 2 is a refrigerant circuit diagram of a refrigerating apparatus in one embodiment of the present invention configured as a multi-type air conditioner, and FIG. 3 is an operation control system diagram of the air conditioner. Is. 1 ... Compressor, 9 ... four-way switching valve, 12 ... Outdoor heat exchanger (heat source side heat exchanger), 20 ... Indoor heat exchanger (use side heat exchanger), 35 ... First temperature Sensor, 45 ... Outdoor control device (operation control means), 50 ... Temperature monitoring unit (heat source side heat exchanger temperature determination means).

Claims (1)

[Scope of utility model registration request] 1. A heat source side heat exchanger (12) and a utilization side heat exchanger (20) are connected to a compressor (1) through a four-way switching valve (9) so that refrigerant can be circulated, and the heat source is also provided. Temperature sensors (35) (35) for detecting the temperature of the side heat exchanger (12)
Are attached to the heat source side heat exchanger (12) at a plurality of different positions, and these temperature sensors (35) (3) are attached.
The operation control means (45) for controlling the operation based on each temperature detected in 5) is provided, and further the plurality of temperature sensors (3).
5) From the respective detected temperatures in (35), the maximum temperature in the cooling operation mode, the average temperature in the heating operation mode, and the minimum temperature in the defrosting operation mode are obtained. A refrigeration system having the operation control means (45) having (50).