JP2012247118A - Air-cooled heat pump chiller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air-cooled heat pump chiller capable of suppressing power consumption even in a demand control during a heating period.SOLUTION: The air-cooled heat pump chiller includes a refrigerant circuit in which a compressor 100, a water-side heat exchanger 12, an electronic expansion valve 13, and an air-side heat exchanger 102 are connected together using a refrigerant piping, for the refrigerant to be circulated inside, a thermal medium circuit to which the water-side heat exchanger 12 is connected and in which a thermal medium for heat-exchanging with the refrigerant following the water-side heat exchanger 12 circulates, an outlet water temperature sensor 16 for measuring temperature of the thermal medium which flows out of the water-side heat exchanger 12, and an air conditioning control unit 15 which, upon receiving a demand instruction, changes an operation mode to a demand mode from a normal mode. The air conditioning control unit 15, when receives the demand instruction during heating, sets a target value of the thermal medium temperature measured by the outlet water temperature sensor 16 to be a value lower than the target value of normal mode by a predetermined amount, for controlling at least the rotational speed of the compressor 100.

Description

  The present invention relates to an air-cooled heat pump chiller, for example, an air-cooled heat pump chiller that performs demand control in a heating state.

  As a conventional air-cooled heat pump chiller, for example, “When a signal is transmitted from the demand control device 5 and the air conditioner 1 detects this signal, the air conditioner 1 stores the current operating capacity and then drops the operating capacity. When transmission of the signal from the demand control device 5 stops, the air conditioner 1 resumes operation with the memorized driving ability, and the demand control is performed on the plurality of air conditioners 1 by using the centralized controller. There is one that “controls” (see Patent Document 1).

  In such a case, it is stated that “cooling or heating operation can be continued even during demand control, and a decrease in comfort level is reduced” (see Patent Document 1).

  For example, “When the air conditioner detects a demand control signal, the air conditioner is stopped when the air conditioner is in the cooling state, the compressor reverse rotation is stopped, the indoor fan is kept running, and the air conditioner is in an operating state. When heating, the operation of the compressor and the indoor fan is stopped, and when the demand control signal is canceled, the operation state immediately before detection of the demand control signal is restored "(see Patent Document 2).

  In such a case, “In response to a demand control signal input during cooling operation, an air blowing operation is performed to continuously supply air to the human body and improve comfort. Also, a demand control during heating operation. In response to the input of the signal, the blower is also stopped, and the supply of wind to the human body is stopped to improve comfort ”(see Patent Document 2).

  Further, for example, “a temperature difference comparison device 12a, 12b that compares a room temperature detected by the temperature detection devices 7a, 7b and a room temperature set by the temperature setting devices 9a, 9b, and the temperature difference comparison device The operation control device 10a, 10b that controls the operation / stop of the compressors 5a, 5b by the operation signal and the stop signal and the set temperature shift that shifts the set temperature by the temperature difference transmitted from the temperature difference comparison devices 12a, 12b. There is a device composed of devices 13a and 13b (see Patent Document 3).

  In such a case, “power demand control can be performed without deteriorating the optimum environment in the building by setting the set temperature higher in the cooling and lowering in the heating according to the temperature difference between the set temperature and the room temperature” (see Patent Document 3). It is said that.

JP-A-6-341690 (Summary, FIG. 1) JP-A-3-144244 (Pages 1, 2) Japanese Patent Laid-Open No. 10-205851 (Summary, FIG. 1)

  However, in any of Patent Documents 1 to 3, there is a problem that when the demand control is performed in the heating state, the degree of reduction in the amount of power used cannot be increased.

  Specifically, the conventional air-cooled heat pump chiller reduces the amount of power used by reducing the operating capacity of the compressor when performing demand control in a cooling state. The conventional air-cooled heat pump chiller reduces the amount of power used by reducing the operating capacity of the compressor even when demand control is performed in a heating state. However, when the conventional air-cooled heat pump chiller compares the amount of electric power to be reduced in the cooling state and the heating state, even if the demand control is performed based on the operating capacity of the compressor in the heating state, The effect of reducing power consumption was not obtained.

  That is, when demand control is performed in a heating state, the configuration in which the power consumption is controlled based on the operating capacity of the compressor cannot significantly reduce the power consumption.

  The present invention has been made to solve the above-described problems, and provides an air-cooled heat pump chiller that can increase the degree of reduction in power consumption even when demand control is performed in a heating state. It is.

  An air-cooled heat pump chiller according to the present invention connects a compressor, a condenser, an expansion valve, and an evaporator with refrigerant piping, and a refrigerant circuit in which refrigerant circulates and the condenser are connected to flow through the condenser. A heat medium circuit in which a heat medium that exchanges heat with the refrigerant circulates, a heat medium temperature measurement sensor that measures the temperature of the heat medium that has flowed out of the condenser, and a normal mode and a demand mode as operation modes. A control device that executes the demand mode when receiving a demand command, and in the demand mode, the control device sets a target value of the heat medium temperature measured by the heat medium temperature measurement sensor as a target of a normal mode. As the target value A lower than the value, at least the number of revolutions of the compressor is controlled.

  The air-cooled heat pump chiller of the present invention changes the target value of the heat medium temperature of the condenser when demand control is performed in the heating state, so that the degree of reduction in power consumption can be reduced even when demand control is performed in the heating state. It has the effect that it can be enlarged.

It is a block diagram which shows the structure of the air-cooling heat pump chiller in Embodiment 1 of this invention in a schematic diagram. It is a figure which shows the refrigerant circuit of the air-cooling heat pump chiller in Embodiment 1 of this invention. It is a characteristic view of the electric energy used with respect to the operating capacity of the compressor in Embodiment 1 of this invention. It is a characteristic view of the electric energy used with respect to the exit water temperature of the water side heat exchanger of the air cooling heat pump chiller in Embodiment 1 of this invention. It is a flowchart which shows the detail of the demand control process in Embodiment 1 of this invention.

  Hereinafter, embodiments of an air-cooled heat pump chiller according to the present invention will be described in detail with reference to the accompanying drawings.

Embodiment 1 FIG.
FIG. 1 is a block diagram schematically showing a configuration of an air-cooled heat pump chiller according to Embodiment 1 of the present invention. As shown in the figure, the configuration of the air-cooled heat pump chiller 1 includes a blower motor 10, a compressor motor 11, a water side heat exchanger 12, an electronic expansion valve 13, a four-way switching valve 14, An air conditioning control device 15 is provided for overall control. Further, an outlet water temperature sensor 16 that measures the outlet water temperature of the water side heat exchanger 12 and an inlet water temperature sensor 17 that measures the water inlet water temperature of the water side heat exchanger 12 are provided. The “outlet water temperature sensor 16” corresponds to the “heat medium temperature measurement sensor” in the present invention.

  The air-cooled heat pump chiller 1 is a central heat source machine, and the heat source machine is directly cooled by outside air. In other words, the air-cooled heat pump chiller is a heat pump system in which heat exchange is performed by the heat source device performing heat absorption and heat dissipation on the air.

  The blower motor 10 is installed in the vicinity of an air-side heat exchanger 102, which will be described later, and generates a wind flow when the air-side heat exchanger 102 exchanges heat with the outside air.

  The compressor motor 11 is for controlling the operating capacity of the compressor 100 described later, and the operating capacity is controlled by controlling the rotational frequency, for example.

  When the water-side heat exchanger 12 is in cooling, the water supplied from the water inlet of the air-cooled heat pump chiller 1 via the piping from the load side is cooled and then cooled from the water outlet of the air-cooled heat pump chiller 1 via the piping. To the load side. On the other hand, during heating, the water supplied from the water inlet of the air-cooled heat pump chiller 1 through the pipe from the load side is heated and then returned from the water outlet of the air-cooled heat pump chiller 1 to the load side through the pipe. .

  That is, the water side heat exchanger 12 is a condenser. The water-side heat exchanger 12 exchanges heat between the high-temperature and high-pressure refrigerant compressed by the compressor motor 11 and the heat medium flowing from the load side (not shown) of the air-cooled heat pump chiller. The refrigerant and the heat medium are, for example, HFC refrigerants such as R410A, R407C, and R404A, HCFC refrigerants such as R22 and R134a, or natural refrigerants such as hydrocarbon and helium. Moreover, when cooling the load side of an air cooling heat pump chiller, a brine etc. may be sufficient.

  The electronic expansion valve 13 is used in a refrigeration cycle as will be described later. For example, during cooling, the refrigerant that has become high pressure in the compressor 100 is changed to a low-pressure refrigerant. During heating, specifically, for example, the target discharge temperature is determined from the outside air temperature and the outlet water temperature. The opening degree is adjusted so as to approach the discharge temperature.

  That is, the electronic expansion valve 13 adjusts the flow rate of the refrigerant flowing through the refrigerant pipe as an expansion valve of the refrigerant circuit. Adjustment of the aperture of the electronic expansion valve 13 can be performed, for example, by adjusting the aperture of the aperture using a stepping motor (not shown).

  The four-way switching valve 14 is used in a refrigeration cycle as described later, and is a switching valve for refrigerant piping at the inlet and outlet of the compressor 100. Thereby, the direction of the flow of the refrigerant is changed, and cooling and heating are performed by a single unit.

  Next, the air conditioning control device 15 includes a storage unit 20, a calculation unit 21, a communication unit 22, and a control unit 23.

  The storage unit 20 includes, for example, a volatile memory and a nonvolatile memory. In the volatile memory, for example, data in the middle of calculation and data indicating various conditions of the air-cooled heat pump chiller are stored, and in the nonvolatile memory, for example, a program for operating the air-cooled heat pump chiller is stored in advance. Yes.

  The calculation unit 21 executes a predetermined calculation based on a program and data stored in the storage unit 20, thereby calculating a control amount for controlling the blower motor 10, the compressor motor 11, and the like. .

  The communication unit 22 is a so-called communication interface. For example, external control signals and various data signals are transmitted / received. Thereby, when a demand control command comes from the outside, the air cooling heat pump chiller can execute the demand control. Further, the communication unit 22 receives the outlet water temperature and the inlet water temperature measured by the outlet water temperature sensor 16 and the inlet water temperature sensor 17 and further measured by various sensors (not shown) installed in the air-cooled heat pump chiller 1. Various sensor signals are received. Based on these received data, the calculation unit 21 described above executes various calculations based on a prescribed program.

  The control unit 23 is configured mainly with a microprocessor, and controls the entire air conditioning control device 15 based on a prescribed program stored in the storage unit 20, and further, the blower motor 10 and the compressor motor 11. Etc. are appropriately controlled.

  Next, details of the refrigerant circuit of the air-cooled heat pump chiller 1 will be described with reference to FIG.

  That is, FIG. 2 is a diagram illustrating a refrigerant circuit of the air-cooled heat pump chiller 1 according to Embodiment 1 of the present invention.

  First, at the time of cooling operation, the refrigerant compressed by the compressor 100 passes through the four-way switching valve 14, passes through the air side heat exchanger 102, the electronic expansion valve 13, and the water side heat exchanger 12 in this order, and again switches to the four side. After passing through the valve 14, it returns to the compressor 100 via the accumulator 103.

  Next, at the time of heating operation, the refrigerant compressed by the compressor 100 passes through the four-way switching valve 14, then passes through the water side heat exchanger 12, the electronic expansion valve 13, and the air side heat exchanger 102, and again switches to the four side. After passing through the valve 14, it returns to the compressor 100 via the accumulator 103.

  Here, when the amount of refrigerant necessary for the refrigerant circuit is compared during the cooling operation and the heating operation, the water-side heat exchanger 12 is more efficient in condensing the refrigerant than the air-side heat exchanger 102. Therefore, the internal volume on the refrigerant side of the heat exchanger can be reduced. Thereby, the amount of refrigerant required for the refrigerant circuit is smaller during the heating operation than during the cooling operation. Therefore, the excess refrigerant liquid flows into the refrigerant quantity adjustment tank 105 via the bypass pipe 104 and is stored. At this time, the refrigerant amount adjustment tank 105 is filled with the refrigerant liquid. Further, when switching to the cooling operation after the heating operation, the amount of refrigerant necessary for the refrigerant circuit is insufficient. Therefore, the shortage can be compensated for by the refrigerant liquid stored in the refrigerant quantity adjustment tank 105 flowing into the refrigeration cycle. At this time, the refrigerant amount adjustment tank 105 contains only the refrigerant gas. With such a refrigerant circuit, the air-cooled heat pump chiller can perform air conditioning.

  Next, the correlation between the operating capacity of the compressor 100 and the amount of power used will be described in detail with reference to FIG.

  FIG. 3 is a characteristic diagram of the amount of power used with respect to the operating capacity of the compressor 100 according to Embodiment 1 of the present invention. As shown in FIG. 3, the cooling performance 200 and the heating performance 201 have different characteristics when the horizontal axis is the operating capacity of the compressor 100 and the vertical axis is the power consumption. That is, during cooling, the amount of power used is greatly reduced as the operating capacity of the compressor 100 is reduced. Therefore, when performing demand control for suppressing the amount of power used, the amount of power used can be reduced by reducing the operating capacity during cooling operation.

  On the other hand, at the time of heating, even if the operating capacity of the compressor 100 is reduced, the reduction degree of the amount of power used is small. Therefore, when performing demand control, even if the operating capacity is reduced as in cooling, it does not greatly contribute to the reduction in power consumption. As a result, in demand control during cooling, it is preferable to use the operating capacity as a control parameter. However, in demand control during heating, it is not preferable to use the operating capacity as a direct control parameter.

  Next, the correlation between the hot water outlet temperature of the water-side heat exchanger 12 and the amount of power used during heating will be described in detail with reference to FIG.

  FIG. 4 is a characteristic diagram of the amount of power used with respect to the outlet water temperature of the water-side heat exchanger 12 of the air-cooled heat pump chiller 1 according to Embodiment 1 of the present invention. As shown in FIG. 4, the heating performance 301 when the horizontal axis is the hot water outlet temperature, that is, the outlet water temperature, and the vertical axis is the used electric energy, the used electric power greatly increases as the outlet water temperature is lowered. To reduce. Therefore, when performing demand control for suppressing the amount of power used, the amount of power used can be reduced by lowering the outlet water temperature during the heating operation. As a result, in demand control during heating operation, it is preferable to use the outlet water temperature as a control parameter.

  Specifically, the air conditioning controller 15 causes the water-side heat exchanger 12 to reduce the outlet water temperature of the water-side heat exchanger 12 to the temperature of the heat medium during demand operation that is lower than the temperature of the heat medium during normal operation. Reduce the refrigerant pressure. Thereby, the pressure ratio when the refrigerant is sent from the water side heat exchanger 12 to the air side heat exchanger 102 is reduced. As a result, in the refrigerant circuit, the power load of the compressor 100 for supplying the refrigerant from the low pressure side to the high pressure side can be significantly reduced. Therefore, the workload of the compressor motor 11 can be greatly reduced. That is, the amount of power used by the compressor motor 11 can be reduced. As a result, the power consumption of the air-cooled heat pump chiller during heating operation can be greatly reduced. “Normal operation” corresponds to “normal mode” in the present invention, “during demand operation” corresponds to “demand mode” in the present invention, and “temperature of heat medium during normal operation” is The “normal mode target value” corresponds to “the heat medium temperature during demand operation” and the “target value A”.

  Next, on the premise of the configuration of the air-cooled heat pump chiller 1 and the demand control method described above, the outlet water temperature of the water-side heat exchanger 12 is controlled during demand control during heating operation, which is the main part of the present invention. Thus, a process for increasing the degree of reduction in the amount of power used will be described while demand control is being performed during heating.

  FIG. 5 is a flowchart showing details of the demand control process in the first embodiment of the present invention. That is, when performing demand control, the amount of power used is reduced by controlling the outlet water temperature of the water-side heat exchanger 12 during heating. When performing demand control, the amount of power used is reduced by controlling the operating capacity as usual during cooling.

  First, it is confirmed whether or not there is a control signal (S100). That is, it is confirmed whether or not a control signal has arrived at the air-cooled heat pump chiller 1. When there is no control signal (NO in S100), it continues to wait until the control signal arrives again. On the other hand, when there is a control signal (S100 YES), the type of the control signal is determined next.

  That is, it is determined whether or not the control signal is a demand signal (S101). When the control signal is not a demand signal (NO in S101), the supply water temperature standard set value during normal operation is set, and the process ends (S102). For example, the outlet water temperature is set to 45 ° C. In addition, as a range of the outlet water temperature at the time of heating, that is, at the time of heating, for example, it is set at intervals of 5 ° C. between 35 ° C. and 55 ° C. However, the lower limit value and the upper limit value are different depending on the model, for example, 32 to 52 ° C and 35 to 70 ° C, for example. Similarly, the set interval may be other than 5 ° C. or may be 1 ° C. intervals. Further, the setting interval may be dynamically changed during demand control. By doing in this way, control according to the change of an external environment is attained.

  Subsequently, when the control signal is a demand signal (S101 YES), it is determined whether or not it is a default supply water temperature low temperature set value (S103). When it is the default supply water temperature low temperature set value (S103 YES), the supply water temperature low temperature set value during demand operation is set, and the process ends (S104). That is, the outlet water temperature is set lower than the current outlet water temperature so as to reduce the amount of power used. By doing in this way, power consumption can be suppressed. Note that the default here refers to the outlet water temperature for suppressing the amount of power used in advance when a demand signal is received.

  On the other hand, when it is not the default supply water temperature low temperature set value (NO in S103), it is determined whether or not it is an automatic correction signal (S105). If it is an automatic correction signal (YES in S105), the details of the automatic correction signal are determined. Specifically, it is determined whether the signal is a scheduled signal (S106). When it is a scheduled signal (YES in S106), the dynamic supply water temperature / low temperature setting value at the time of demand scheduling operation is set, and the process ends (S107).

  Specifically, the automatic correction mentioned here is not control that sets the outlet water temperature that becomes the target temperature each time, but control that continues to suppress the power consumption for a certain period. For example, if the specified period of time has elapsed after the outlet water temperature has been lowered in order to significantly reduce the amount of power used in the first stage, it is set to suppress the amount of power used at the beginning while suppressing the amount of power used. The outlet water temperature is set to a temperature higher than the outlet water temperature, and after a predetermined time has elapsed, the outlet water temperature is returned to the original supply water temperature standard set value during normal operation. By performing such processing, for example, when the power demand is rapidly tightened, it is possible to significantly reduce the power consumption once and then gradually reduce the power consumption. That is, the value of the outlet water temperature can be changed every predetermined time. As a result, even when the power demand suddenly tightens and then the power demand settles down, it is possible to switch from demand operation to normal operation with a single demand command, so the air-cooled heat pump chiller can be monitored. It can be done efficiently.

  Moreover, the scheduled signal here is a process which repeats the process which suppresses electric power consumption intermittently only for a fixed period, for example. Specifically, this is a process for suppressing the amount of power used only from 10:00 am to 1 pm every Monday for one month. In this way, for example, even in the case of a planned power outage where it is known in advance that the power demand is tight, it is possible to execute the automatically scheduled power consumption reduction process. Of course, it is needless to say that scheduling may be performed only when the power demand is tight on a daily basis. In short, when a demand command is received, the demand operation can be executed for one or more predetermined periods. As a result, when it is clear in advance that power is tight in advance, for example, it can be scheduled to automatically run on demand, so efficient monitoring of power load demand and supply is possible. can do.

  On the other hand, when the signal is not a scheduled signal (NO in S106), it is set to the supply water temperature / low temperature set value manually set during the demand operation, and the process ends (S108). The manual setting at the time of demand operation here is, for example, when the operator is monitoring the power demand and the power demand suddenly starts to be tight for some reason, but the previous power demand cannot be predicted. In addition, as a control amount, while the outlet water temperature is lowered linearly, the demand signal is transmitted after suddenly manually setting the lowering width to be large at first and then to be small. As such a setting method, for example, the amount by which the outlet water temperature is lowered may be controlled by tuning a gain adjustment parameter (not shown).

  Next, when it is not the automatic correction signal (S105 NO), the demand level is subsequently determined (S109). That is, by determining which demand level it is, the amount of power consumption is determined. For example, the outlet water temperature may be 45 ° C. as the demand level i, the outlet water temperature may be 40 ° C. as the demand level ii, and the outlet water temperature may be 35 ° C. as the demand level iii.

  Specifically, if the demand level is i (i in S109), the supply water temperature is set to the low temperature setting value at the time of the demand level i operation, and the process ends (S110). If the demand level is ii (ii of S109), the supply water temperature is set to the low temperature setting value during the operation of the demand level ii, and the process ends (S111). If the demand level is iii (S109 iii), the supply water temperature is set to the low temperature setting value during the demand level iii operation, and the process ends (S112). Note that the demand level is not limited to three levels, and may be a finer level or a lower level. For example, the demand level may be divided into steps of 0.5 ° C., and the demand level may be divided into steps of 10 ° C. In short, the control based on the demand level is a process of setting the outlet water temperature that becomes the target temperature every time. Thus, a plurality of demand commands can be received, and the outlet water temperature can be set according to the type of the received demand commands.

  With the above configuration, when demand control is performed during heating operation, the degree of reduction in power consumption can be increased by changing the target value of the heat medium temperature of the condenser even when demand control is performed in the heating state. Can do. Thereby, energy consumption can be reduced.

  Specifically, when demand control is performed during heating operation, the air conditioning controller 15 lowers the refrigerant pressure of the water-side heat exchanger 12 by lowering the outlet water temperature of the water-side heat exchanger 12. Thereby, the pressure ratio when the refrigerant is sent from the water side heat exchanger 12 to the air side heat exchanger 102 is reduced. As a result, the power load of the compressor 100 can be reduced. Therefore, the amount of power used by the compressor motor 11 can be reduced.

  1: air-cooled heat pump chiller, 10: motor for blower, 11: motor for compressor, 12: water-side heat exchanger, 13: electronic expansion valve, 14: four-way switching valve, 15: air-conditioning control device, 16: outlet water temperature sensor 17: Inlet water temperature sensor, 20: Storage unit, 21: Calculation unit, 22: Communication unit, 23: Control unit, 100: Compressor, 102: Air-side heat exchanger, 103: Accumulator, 104: Bypass piping, 105 : Refrigerant amount adjustment tank, 200: Cooling performance, 201, 301: Heating performance.

Claims (4)

A refrigerant circuit in which a compressor, a condenser, an expansion valve, and an evaporator are connected by a refrigerant pipe, and the refrigerant is circulated therein;
A heat medium circuit that is connected to the condenser and in which a heat medium that exchanges heat with the refrigerant flowing through the condenser circulates;
A heat medium temperature measurement sensor for measuring the temperature of the heat medium flowing out of the condenser;
A control device that has a normal mode and a demand mode as an operation mode, and executes the demand mode when a demand command is received during heating operation;
With
The controller is
In the demand mode, the target value A of the heat medium temperature measured by the heat medium temperature measurement sensor is set to a target value A lower than the target value of the normal mode, and at least the rotation speed of the compressor is controlled. Air-cooled heat pump chiller. The controller is
It receives multiple types of demand commands,
The air-cooled heat pump chiller according to claim 1, wherein the target value A is set according to the type of the received demand command. The controller is
The air-cooled heat pump chiller according to claim 1 or 2, wherein the target value A is changed at predetermined time intervals. The controller is
The air-cooled heat pump chiller according to any one of claims 1 to 3, wherein, when a demand command is received, the demand mode is executed for one or more predetermined periods.

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