JP5537257B2 - Refrigeration cycle equipment - Google Patents

Description

  The present invention relates to a refrigeration cycle apparatus that determines whether a discharge temperature sensor has dropped out.

  Conventionally, in this type of refrigeration cycle apparatus, as disclosed in Patent Document 1, a refrigeration circuit in which a compressor, a heat exchanger, a decompression means, and an evaporator are connected in an annular shape, and the temperature of refrigerant discharged from the compressor are detected. A discharge temperature sensor, and when the discharge temperature detected by the discharge temperature sensor is equal to or lower than a predetermined temperature after a predetermined time has elapsed since the start of the compressor, it is determined that the discharge temperature sensor is in an abnormal state There was something to do.

  Moreover, in a heat pump hot water supply apparatus, as disclosed in Patent Document 2, a compressor, a hot water supply heat exchanger, a decompression unit, a refrigeration circuit in which an evaporator is connected in an annular shape, and a discharge temperature for detecting the temperature of refrigerant discharged from the compressor A boiling temperature sensor that detects a temperature at the outlet of the hot water supply heat exchanger, and the boiling temperature sensor detects a discharge temperature detected by the discharge temperature sensor after a predetermined time has elapsed since the start of the compressor. When the temperature is equal to or lower than the temperature to be detected, it has been determined that the discharge temperature sensor is in an abnormal drop-off state.

JP 05-99543 A JP 2003-222406 A

  However, in this conventional patent document 1, since it is not possible to determine abnormality until a predetermined time has elapsed, there is a possibility that the high temperature and high pressure state may be continued for a long time. Thus, if the predetermined time is set to a short time or the predetermined temperature is set to a low temperature, there is a problem that false detection increases in a situation where the ambient temperature is low.

  Moreover, in the thing of patent document 2, when a boiling target temperature is high temperature, it may become an overheated state with a hot water supply heat exchanger until predetermined time passes after the start-up of a compressor. There was a possibility of adversely affecting the durability of the equipment. Therefore, if the predetermined time is set to a short time, there is a problem that false detection increases in a situation where the ambient temperature is low.

  SUMMARY OF THE INVENTION An object of the present invention is to determine an abnormal drop-off state of a discharge temperature sensor more accurately and in a shorter time than in the past.

Therefore, in order to solve the present invention, a refrigeration circuit in which a compressor, a heat exchanger, a decompression unit, and an evaporator are connected in an annular shape, a discharge temperature sensor that detects the temperature of refrigerant discharged from the compressor, Pressure detection means for detecting the refrigerant pressure, and in a refrigeration cycle apparatus that is in a supercritical state on the high pressure side, the discharge temperature detected by the discharge temperature sensor after the start of starting the compressor is a predetermined temperature or less, When the high pressure side pressure detected by the pressure detection means is equal to or higher than a lower limit predetermined pressure at which the compressor and the refrigeration cycle can be regarded as operating normally, the discharge temperature sensor It was determined that it was in an abnormal state, and the operation was stopped.

In addition, a refrigeration circuit in which a compressor, a heat exchanger, a decompression unit, and an evaporator are connected in an annular shape, a discharge temperature sensor that detects the temperature of refrigerant discharged from the compressor, and a pressure detection that detects refrigerant pressure on the high-pressure side A refrigeration cycle apparatus that is in a supercritical state on the high-pressure side, and a discharge temperature detected by the discharge temperature sensor after a predetermined start-up time has elapsed from the start of startup of the compressor is equal to or lower than a predetermined temperature, and When the high pressure side pressure detected by the pressure detecting means is equal to or higher than a predetermined pressure that is a lower limit at which the compressor and the refrigeration cycle can be regarded as operating normally, the discharge temperature sensor is in an abnormal state of dropping. Judgment was made and the operation was stopped.

In addition, a refrigeration circuit in which a compressor, a heat exchanger, a decompression unit, and an evaporator are connected in an annular shape, a discharge temperature sensor that detects the temperature of refrigerant discharged from the compressor, and a pressure detection that detects refrigerant pressure on the high-pressure side A refrigeration cycle apparatus that is in a supercritical state on the high-pressure side, the discharge temperature detected by the discharge temperature sensor is equal to or lower than a predetermined temperature after the start of the compressor, and the pressure detection means When the state in which the high pressure side pressure to be detected is equal to or higher than the lower limit predetermined pressure at which the compressor and the refrigeration cycle are normally operated continues for a predetermined determination time, or from the start of starting the compressor discharge temperature of the discharge temperature sensor is detected after a predetermined determination time elapses longer predetermined start-up time than is the predetermined temperature or lower, and the high pressure side pressure where the pressure detecting means detects the Wherein if the compressor and the refrigeration cycle is the lower limit of the predetermined pressure or more which can be regarded to be operating normally, it is determined that the dropping abnormal state of the discharge temperature sensor, and to stop the operation.

  As described above, according to the present invention, it is possible to reduce the possibility of erroneous detection of the dropout abnormality of the discharge temperature sensor as much as possible, and at the same time, it is possible to determine the dropout abnormal state at an early stage. It becomes possible to prevent this from happening.

The schematic block diagram of the heat pump hot-water supply apparatus of one Embodiment of this invention Flow chart showing the operation of the same embodiment

Next, a heat pump hot water supply apparatus according to an embodiment of the refrigeration cycle apparatus of the present invention will be described with reference to the drawings.
1 is a compressor that compresses refrigerant, 2 is a hot water supply heat exchanger as a heat exchanger that exchanges heat between the compressed high-temperature and high-pressure refrigerant and hot water, and 3 is a decompression that depressurizes the refrigerant radiated by the hot water supply heat exchanger 2 Electronic expansion valve as means, 4 is an air heat exchanger as an evaporator for evaporating a low-temperature and low-pressure refrigerant, 5 is a blowing means for blowing outside air to the air heat exchanger 4, 6 is a compressor 1, hot water supply heat exchanger 2 is a refrigeration circuit in which an electronic expansion valve 3 and an air heat exchanger 4 are annularly connected by a refrigerant pipe 7. The refrigeration circuit 6 uses carbon dioxide as a refrigerant and is designed to be in a supercritical state on the high pressure side.

  8 is a hot water storage tank for storing hot water for hot water supply, 9 is a water supply pipe connected to the lower part of the hot water storage tank 8, 10 is a hot water supply pipe connected to the upper part of the hot water storage tank 8, and 11 is a lower part of the hot water storage tank 8 and a hot water supply heat exchanger 2. , 12 is a return pipe connecting the outlet side of the hot water heat exchanger 2 and the upper part of the hot water storage tank 8, and 13 is provided in the middle of the forward pipe 11, and hot water taken out from the lower part of the hot water storage tank 8 is heated. This is a circulation pump that circulates to the exchanger 2 and returns to the upper part of the hot water storage tank 8.

  14 is a discharge temperature sensor for detecting the temperature of the refrigerant discharged from the compressor 1, 15 is a pressure sensor as pressure detection means for detecting the high-pressure side pressure of the refrigeration circuit 6, and 16 is provided in the blowing path of the blowing means 5. An outside air temperature sensor that detects the outside air temperature, 17 is an incoming water temperature sensor that detects the temperature of hot water flowing into the hot water supply heat exchanger 2, and 18 is a boiling temperature sensor that detects the temperature of hot water flowing out of the hot water supply heat exchanger 2. , 19 are hot water storage temperature sensors which are provided in plural above and below the side surface of the hot water storage tank 8 and detect the hot water storage temperature.

  Reference numeral 20 denotes a control means for controlling the heat pump hot water supply apparatus, which stores a program for controlling the operation in advance and has a calculation, comparison, storage function, and clock function.

  Next, the operation of the heat pump hot water supply apparatus will be described. When the control means 20 receives a boiling operation request, the control means 20 drives the compressor 1, the blower means 5 and the circulation pump 13 at predetermined initial rotational speeds, respectively. 3 is controlled to a predetermined initial opening, and the boiling operation is started (step S1), and the time counting from the start of the operation is started.

  Before the time count from the start of operation exceeds a predetermined start-up time (here, 10 minutes) (No in step S2), the high pressure side pressure detected by the pressure sensor 15 is normal for the compressor 1 and the refrigeration circuit 6. If a state higher than the lower limit predetermined pressure (here, 8 MPa) that can be regarded as operating is continued for a predetermined determination time (here, 3 minutes) (Yes in step S3), the process proceeds to the next step.

  In step S4, when the refrigerant discharge temperature detected by the discharge temperature sensor 14 is higher than a predetermined temperature (here, 50 ° C.), the compressor 1 and the refrigeration circuit 6 operate normally, and the discharge temperature Since the sensor 14 can be regarded as functioning normally, the operation is continued as it is (step S5).

  On the other hand, if the refrigerant discharge temperature detected by the discharge temperature sensor 14 is lower than the predetermined temperature in step S5, the result of step S4 is No, the process proceeds to step S6, and the high-pressure side pressure detected by the pressure sensor 15 is again detected. It is checked whether the compressor 1 and the refrigeration circuit 6 are in a state higher than a lower limit predetermined pressure (here, 8 MPa) that can be regarded as operating normally.

  If the pressure is higher than the predetermined pressure, the discharge temperature does not rise despite the fact that the pressure on the high pressure side of the refrigeration circuit 6 has risen normally. The determination is YES in step S6, and the process proceeds to the next step S7. Immediately, the operation of the compressor 1, the electronic expansion valve 3, the blower 5, and the circulation pump 13 is stopped to stop the operation.

  As described above, after the start of the compressor 1, the state in which the discharge temperature detected by the discharge temperature sensor 14 is equal to or lower than the predetermined temperature and the high pressure side pressure detected by the pressure sensor 15 is equal to or higher than the predetermined pressure is predetermined. If it continues for a period of time, it is determined that the discharge temperature sensor 14 is in an abnormal state, so that the abnormal state can be determined at an early stage, and the refrigeration circuit 6 can be prevented from becoming an abnormally high temperature and high pressure state. In addition, even if the refrigeration circuit 6 is in an abnormally high temperature and high pressure state, the abnormal state can be determined in a short time, so that the time that adversely affects the refrigeration circuit 6 can be suppressed.

  On the other hand, when the discharge temperature sensor 14 is operating normally in a normal mounting state, a predetermined determination time elapses with the high-pressure side pressure rising to a predetermined pressure or higher, so the result is YES in step S3. Proceeding to S4, the discharge temperature sensor 14 detects a predetermined temperature or higher, the compressor 1 and the refrigeration circuit 6 are operating normally, and the discharge temperature sensor 14 can be regarded as functioning normally, so the operation is continued as it is (Step S5).

  Here, when the outside air temperature is extremely low and it takes a long time to start up the refrigeration circuit 6, a predetermined start-up time elapses without the refrigerant pressure rising to the predetermined pressure. In step S4, the discharge temperature is checked by the discharge temperature sensor 14. However, since it takes time to start up the refrigeration circuit 6, a predetermined temperature or less is detected, and the process proceeds to step S6.

  At this time, since the high-pressure side pressure detected by the pressure sensor 15 is lower than the lower limit predetermined pressure at which the compressor 1 and the refrigeration circuit 6 can be regarded as operating normally, the discharge temperature sensor 14 is in an abnormal drop-off state. The operation is continued by repeating step S4 and step S6, and when the discharge temperature is raised to a predetermined temperature or higher, the process proceeds to step S5, and the compressor 1 and the refrigeration circuit 6 operate normally. Continue driving as it is.

  In this way, when the outside air temperature or the ambient temperature of the refrigeration circuit 6 is low and it takes a long time to start up the refrigeration circuit 6, the discharge temperature sensor 14 is not erroneously detected as a drop-off abnormal state, and carelessly. Never stop driving.

  Further, when a predetermined start-up time from the start of operation elapses before the predetermined determination time elapses after the refrigerant pressure has increased to the predetermined pressure, the discharge temperature detected by the discharge temperature sensor 14 in step S4 is the predetermined temperature. If not, if it is detected in step S6 that the high-pressure side pressure detected by the pressure sensor 15 is higher than the lower limit predetermined pressure at which the compressor 1 and the refrigeration circuit 6 can be regarded as operating normally. Then, it is determined that the discharge temperature sensor 14 is in an abnormal state, and the result of step S6 is Yes, and the process proceeds to the next step S7, and immediately the operation of the compressor 1, the electronic expansion valve 3, the blower 5, and the circulation pump 13 is stopped. Stop operation.

  As described above, the discharge temperature detected by the discharge temperature sensor 14 after the predetermined start-up time from the start of the compressor 1 is equal to or lower than the predetermined temperature, and the high-pressure side pressure detected by the pressure sensor 15 is equal to or higher than the predetermined pressure. In some cases, since it is determined that the discharge temperature sensor 14 is in an abnormal state, even if the outside air temperature or the ambient temperature of the refrigeration circuit 6 is low and it takes time to start up the refrigeration circuit 6, it is accurate. In addition, it is possible to detect an abnormal drop-off state of the discharge temperature sensor 14 and to safely stop the operation.

  As described above, according to the present invention, it is possible to reduce the possibility of erroneous detection of an abnormal state of dropout of the discharge temperature sensor as much as possible, to prevent the operation from being inadvertently stopped, and to determine the abnormal state of dropout at an early stage. It is possible to prevent the refrigeration circuit from becoming an abnormally high temperature and high pressure state.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without changing the gist. For example, the present invention can be applied to an air conditioner or a hydrocarbon refrigerant can be used as a refrigerant. It is also possible to operate at supercritical pressure on the high pressure side. Further, instead of the pressure sensor 15, a pressure switch that operates at a predetermined pressure or higher may be used.

1 Compressor 2 Hot Water Heat Exchanger (Heat Exchanger)
3 Electronic expansion valve (pressure reduction means)
4 Air heat exchanger (evaporator)
6 Refrigeration circuit 14 Discharge temperature sensor 15 Pressure sensor (pressure detection means)
20 Control means

Claims (3)

A compressor, a heat exchanger, a decompression means, a refrigeration circuit in which an evaporator is connected in an annular shape, a discharge temperature sensor for detecting the temperature of refrigerant discharged from the compressor, and a pressure detection means for detecting a refrigerant pressure on the high-pressure side In a refrigeration cycle apparatus that is in a supercritical state on the high-pressure side, the discharge temperature detected by the discharge temperature sensor is equal to or lower than a predetermined temperature after the start of startup of the compressor, and the pressure detection means detects If the high-pressure side pressure is equal to or higher than the lower limit predetermined pressure at which the compressor and the refrigeration cycle can be considered to be operating normally, it is determined that the discharge temperature sensor is in an abnormal state. The refrigeration cycle apparatus characterized in that the operation is stopped. A compressor, a heat exchanger, a decompression means, a refrigeration circuit in which an evaporator is connected in an annular shape, a discharge temperature sensor for detecting the temperature of refrigerant discharged from the compressor, and a pressure detection means for detecting a refrigerant pressure on the high-pressure side In a refrigeration cycle apparatus that is in a supercritical state on the high-pressure side, a discharge temperature detected by the discharge temperature sensor after a predetermined start-up time has elapsed since the start of starting the compressor is equal to or lower than a predetermined temperature, and When the high pressure side pressure detected by the pressure detecting means is equal to or higher than a predetermined lower limit pressure at which the compressor and the refrigeration cycle can be regarded as operating normally, it is determined that the discharge temperature sensor is in an abnormal state. The refrigeration cycle apparatus characterized in that the operation is stopped. A compressor, a heat exchanger, a decompression means, a refrigeration circuit in which an evaporator is connected in an annular shape, a discharge temperature sensor for detecting the temperature of refrigerant discharged from the compressor, and a pressure detection means for detecting a refrigerant pressure on the high-pressure side In a refrigeration cycle apparatus that is in a supercritical state on the high-pressure side, the discharge temperature detected by the discharge temperature sensor is equal to or lower than a predetermined temperature after the start of startup of the compressor, and the pressure detection means detects When the state where the high-pressure side pressure is equal to or higher than the lower limit predetermined pressure at which the compressor and the refrigeration cycle are normally operating continues for a predetermined determination time, or after the start of the compressor, discharge temperature of the discharge temperature sensor after determination time longer the predetermined start-up time than is detected is lower than a predetermined temperature, and high pressure side pressure where the pressure detecting means detects the said If compressor and the refrigeration cycle is higher than a predetermined pressure lower limit which can be regarded to be operating normally, and characterized in that determining that a falling abnormal state of the discharge temperature sensor, and to stop the operation Refrigeration cycle equipment.

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