JP6072901B2 - Heat pump device and air conditioning system - Google Patents

Description

  The present invention relates to a heat pump device capable of defrosting operation. In particular, it relates to the determination to start the defrosting operation.

  Usually, in an evaporator in a heat pump apparatus, when the evaporation temperature is 0 ° C. or lower and the dew point temperature of air or lower, a frosting phenomenon occurs in which frost grows on the evaporator surface. When such a frosting phenomenon occurs, an increase in ventilation resistance and an increase in thermal resistance in the evaporator are caused, and the operation efficiency in the evaporator is reduced. Therefore, in the heat pump device, it is necessary to perform a defrosting operation (defrosting operation) that guides refrigerant discharged from the compressor to the evaporator and removes frost that has grown on the surface of the evaporator.

  Conventionally, there is a heat pump device capable of performing a defrosting operation for melting frost attached to an evaporator. As such a device, “a heat pump device in which the start timing of the defrost operation is determined so that the one-cycle average COP (performance coefficient, operation efficiency) from the start of the heating operation to the end of the defrost operation is maximized” has been proposed. (For example, refer to Patent Document 1). The heat pump device calculates a current COP and a one-cycle COP based on the refrigerant condensation temperature and the refrigerant evaporation temperature. When it is determined that the current COP is smaller than one cycle COP, the start of the defrosting operation is commanded.

JP 2010-060150 A

  In the heat pump device described in Patent Document 1, the COP is estimated and calculated using the refrigerant condensation temperature and the refrigerant evaporation temperature. However, for example, when the compressor frequency, the air temperature, or the like changes, at least one of the refrigerant condensing temperature and the evaporation temperature changes, and the COP also changes accordingly. For this reason, for example, when the calculated COP decreases even though the evaporator is not frosted, it may be determined that it is the start timing of the defrosting operation.

  This invention was made in order to solve the said subject, and it aims at providing the heat pump apparatus which can determine the defrost start more correctly.

In order to solve the above-described problems, a heat pump device according to the present invention includes a compressor, a condenser, an expansion device, and an evaporator connected to form a refrigerant circuit, and a condenser that detects a saturation temperature of the condenser as a condensation temperature. Temperature detection means, evaporation temperature detection means for detecting the saturation temperature of the evaporator as the evaporation temperature, compressor frequency detection means for detecting the rotation frequency of the compressor as the compressor frequency, compressor frequency, condensation temperature and evaporation temperature Calculate the corrected condensing temperature and the corrected evaporating temperature based on the above, calculate the current operating efficiency by dividing the ability based on the corrected condensing temperature by the power consumption calculated from the difference between the corrected condensing temperature and the corrected evaporating temperature, at least it calculates the average operating efficiency until defrosting completion from start of operation when the at was defrosting time, when judged that the operation efficiency is equal to or less than the average operating efficiency evaporator And a control unit that performs processing for determining the start of defrosting.

  According to this invention, the condensation temperature and the evaporation temperature are corrected, and the operation efficiency and the like are calculated based on the corrected condensation temperature and the corrected evaporation temperature. It is possible to accurately determine the start.

It is a figure which shows schematic structure of the heat pump apparatus 100 concerning Embodiment 1 of this invention. It is a block diagram which shows the outline of the input-output relationship of the signal in the control system of the heat pump apparatus 100 concerning Embodiment 1 of this invention. It is a figure which shows the graph of the relationship between time and COP in Embodiment 1 of this invention. It is a figure which shows the graph of the relationship between the time in 1 cycle in Embodiment 1 of this invention, and COP. It is a figure which shows the flowchart of an example of the flow of the process regarding the defrost start determination control of the heat pump apparatus. It is a figure which shows the graph of the relationship between the instantaneous COP and average COP in Embodiment 1 of this invention. It is a figure which shows the graph of the relationship between the instantaneous COP and 1 cycle average COP in Embodiment 1 of this invention. It is a figure which shows the graph of the relationship between the instantaneous COP and average COP in Embodiment 1 of this invention. It is a figure which shows the relationship between the compressor frequency F in Embodiment 1 of this invention, evaporation temperature Te, and the condensation temperature Tc. It is a figure which shows the relationship between the evaporator intake air temperature Tae and the evaporation temperature Te in Embodiment 1 of this invention. It is a figure which shows the relationship between the condenser intake air temperature Tac and the condensation temperature Tc in Embodiment 1 of this invention. It is a figure which shows the flowchart of an example of the flow of a process regarding the defrost start determination control of the heat pump apparatus 100 concerning Embodiment 1 of this invention. It is a figure which shows the relationship between the instantaneous heating capability and 1 cycle average heating capability in Embodiment 2 of this invention. It is a figure which shows the time change of the instantaneous COP and heating capability in Embodiment 2 of this invention. It is a figure which shows the change of the instantaneous COP and heating capability when the condenser intake air temperature Tac in Embodiment 2 of this invention changes. It is a figure which shows the change of the instantaneous COP and the heating capability when the evaporator intake air temperature Tae in Embodiment 2 of this invention changes. It is a figure which shows the flowchart of an example of the flow of the process regarding the defrost start determination control of the heat pump apparatus 100 concerning Embodiment 2 of this invention. It is the figure which showed the time change of the instantaneous COP and heating capability in Embodiment 3 of this invention. It is the figure which showed the time change of the instantaneous COP and heating capability in Embodiment 3 of this invention.

Embodiment 1 FIG.
FIG. 1 is a diagram showing a schematic configuration of a heat pump apparatus 100 according to Embodiment 1 of the present invention. The refrigerant circuit configuration and operation of the heat pump apparatus 100 will be described with reference to FIG. The heat pump apparatus 100 is an apparatus such as a refrigeration apparatus that performs a cooling operation on a target space or an object by circulating a refrigerant, an air conditioning system that performs a cooling operation or a heating operation that heats an air-conditioning target space. is there. Here, it demonstrates as what is an air conditioning system as a representative. Here, in the following drawings including FIG. 1, the size relationship of each component may be different from the actual one. In addition, in the following drawings including FIG. 1, the same reference numerals denote the same or equivalent parts, and this is common to the whole text of the embodiments described below. . And the form of the component represented by the whole text of specification is an illustration to the last, Comprising: It is not limited to the form described in the specification.

  As shown in FIG. 1, the heat pump device 100 includes a compressor 1, a condenser 2, an expansion device 3, and an evaporator 4 that are sequentially connected in series by a refrigerant pipe to form a heat pump circuit. Further, a condenser fan 5 and condensation temperature detection means 11 are provided in the vicinity of the condenser 2. An evaporator fan 6 and an evaporation temperature detecting means 12 are provided in the vicinity of the evaporator 4. The condensing temperature detecting means 11 and the evaporating temperature detecting means 12 detect the temperature, respectively, and send a signal including the detected temperature value (detected value) to the control device 50 for overall control of the heat pump device 100.

  The compressor 1 sucks refrigerant flowing through the refrigerant pipe, compresses the refrigerant, and discharges the refrigerant in a high temperature / high pressure state. The condenser 2 performs heat exchange between the refrigerant and the fluid to condense the refrigerant. In this embodiment, the fluid is air. The expansion device 3 decompresses and expands the refrigerant passing through the refrigerant pipe. The expansion device 3 may be constituted by a throttle device such as an electronic expansion valve. The evaporator 4 performs heat exchange between the refrigerant and air, and evaporates the refrigerant. The condenser fan 5 supplies air to the condenser 2. The evaporator fan 6 supplies air to the evaporator 4.

  The condensation temperature detection means 11 is a detection device such as a temperature sensor that detects the saturation temperature (condensation temperature) of the condenser 2. The evaporation temperature detection means 12 is a detection device such as a temperature sensor that detects the saturation temperature (evaporation temperature) of the evaporator 4. The evaporator suction air temperature detection means 13 serving as the evaporator suction temperature detection means is a detection device such as a temperature sensor that detects the temperature of the air flowing into the evaporator 4 (evaporator suction air temperature). The condenser suction air temperature detection means 14 serving as the condenser suction temperature detection means is a detection device such as a temperature sensor that detects the temperature of the fluid (air) flowing into the condenser 2 (condenser suction air temperature). . The compressor frequency detection means 15 is a device that detects the rotation frequency of the compressor (hereinafter referred to as the compressor frequency).

  The control device 50 is composed of, for example, a microcomputer. For example, the rotational frequency of the compressor 1, the condenser fan 5 and the evaporation based on the detection values (condensation temperature detected by the condensation temperature detection means 11, evaporation temperature detected by the evaporation temperature detection means 12, etc.) from each detection means described above. Control is performed by determining the rotational speed of the fan 6 for equipment. For example, the opening degree of the expansion device 3 is controlled. Moreover, when changing the flow path of a refrigerant | coolant by driving | operating like an air conditioning system etc., it has the function to control switching of the four-way valve (illustration omitted) which is a flow path switching apparatus of a refrigerant | coolant. . The operation of the control device 50 according to the present embodiment will be described in detail later with reference to FIG.

  Here, operation | movement of the heat pump apparatus 100 is demonstrated easily based on the flow of a refrigerant | coolant. When the heat pump device 100 starts operation, the compressor 1 is first driven. The high-temperature and high-pressure gas refrigerant compressed by the compressor 1 is discharged from the compressor 1 and flows into the condenser 2. In the condenser 2, the gas refrigerant that has flowed in is condensed while dissipating heat to the fluid to be heat exchanged, and becomes a low-temperature and high-pressure refrigerant. This refrigerant flows out of the condenser 2, is decompressed by the expansion device 3, and becomes a gas-liquid two-phase refrigerant. This gas-liquid two-phase refrigerant flows into the evaporator 4. The refrigerant that has flowed into the evaporator 4 absorbs heat from the air, thereby evaporating. This refrigerant flows out of the evaporator 4 and is sucked into the compressor 1 again. Here, during the operation of the heat pump device 100, the condensation temperature detection means 11 and the evaporation temperature detection means 12 each detect the temperature and send a signal related to the detection value to the control device 50.

  FIG. 2 is a block diagram schematically showing the input / output relationship of signals in the control system of the heat pump apparatus 100 according to Embodiment 1 of the present invention. Based on FIG. 2, the function of the control apparatus 50 is demonstrated in detail. As illustrated in FIG. 2, the control device 50 includes a memory 51 serving as a storage device and a calculation unit 52 that performs calculation processing based on the detection value. The memory 51 stores, for example, detection values detected by the condensation temperature detection means 11, the evaporation temperature detection means 12, the evaporator intake air temperature detection means 13, the condenser intake air temperature detection means 14, and the compressor frequency detection means 15 as data. (Remember. Then, the calculation unit 52 performs calculation processing based on the detection value stored in the memory 51. As described above, the control device 50 sends signals to the compressor 1, the four-way valve (not shown), the expansion device 3, the condenser fan 5, and the evaporator fan 6 based on the calculation result in the calculation unit 52. To control.

  For example, when the control device 50 controls the heating operation of the heat pump device 100, the instantaneous COP (= COP) representing the current operation efficiency is estimated from the equation (1) based on the condensation temperature Tc and the evaporation temperature Te. (Hereinafter referred to as computation). Here, Formula (1) is a definition formula of Carnot efficiency. The power consumption is calculated by the condensation temperature Tc−evaporation temperature Te.

[Equation 1]
COP = (Tc + 273.15) / (Tc−Te) (1)

  FIG. 3 is a graph showing a relationship between time and COP in the first embodiment of the present invention. Based on FIG. 3, the relationship between the time of the heat pump apparatus 100 and the instantaneous COP will be described. In FIG. 3, the horizontal axis represents time, and the vertical axis represents COP. In the heat exchange between the refrigerant and the air in the evaporator 4, when the temperature of the refrigerant is 0 ° C. or less and the air dew point temperature or less, moisture contained in the air adheres to the evaporator 4 and turns into frost. A growing frosting phenomenon occurs. When the frosting phenomenon in the evaporator 4 proceeds, the amount of heat exchange in the evaporator 4 decreases due to an increase in ventilation resistance and an increase in thermal resistance, and the instantaneous COP decreases as shown in FIG. Therefore, defrosting is necessary. Here, a defrosting operation in which a high-temperature refrigerant is passed through the evaporator 4 for defrosting will be described, but the defrosting method is not limited, for example, overheating with a heater or the like.

  In the instantaneous COP (= COP) shown in the equation (1), the decrease in the evaporation temperature Te is larger than the condensation temperature Tc together with the frost formation, and the decrease in the instantaneous COP due to the frost formation can be accurately captured. For example, the condensation temperature Tc, which was Tc = 49 ° C. at the start of operation, becomes Tc = 47 ° C. immediately before the start of defrosting, and is reduced by about 2 ° C. On the other hand, the evaporation temperature Te is Te = −2 ° C. at the start of operation, but immediately before the start of defrosting, becomes Te = −6 ° C., decreases by about 4 ° C., and instantaneous COP decreases with frost formation. Become.

  FIG. 4 is a graph showing a relationship between time and COP in one cycle in Embodiment 1 of the present invention. The one-cycle average COP of the heat pump apparatus 100 will be described based on FIG. The operation efficiency in the case of the operation accompanied by the defrosting operation is evaluated by the one-cycle average COP when the cycle from the start of the normal operation to the end of the defrosting operation is defined as one cycle as shown in FIG. Here, since the defrosting operation does not contribute to the operation, the instantaneous COP becomes zero. Therefore, if the defrosting operation is started at a timing at which the one-cycle average COP becomes the highest, energy saving can be effectively realized, and therefore the start timing becomes important.

  FIG. 5 is a diagram illustrating a flowchart of an example of a process flow relating to the defrosting start determination control of the heat pump apparatus 100. FIG. 6 is a graph showing a relationship between the instantaneous COP and the average COP in the first embodiment of the present invention. FIG. 7 is a graph showing a relationship between the instantaneous COP and the one-cycle average COP in the first embodiment of the present invention. FIG. 8 is a graph showing a relationship between the instantaneous COP and the average COP in Embodiment 1 of the present invention. Based on FIGS. 5-8, the flow of the process regarding the defrost start determination control of the heat pump apparatus 100 is demonstrated. Here, in FIGS. 6 to 8, the horizontal axis represents time, and the vertical axis represents COP.

  Based on FIG. 5, the process regarding the defrost start which the control apparatus 50 performs is demonstrated. When the heat pump device 100 starts operation, the control device 50 stores the condensation temperature Tc, which is a detection value detected by the condensation temperature detection unit 11, and the evaporation temperature Te, which is a detection value detected by the evaporation temperature detection unit 12, in the memory 51. (Step S101). And the calculating part 52 calculates the instantaneous COP (= COP) represented by the said Formula (1) (step S102). Thereafter, as shown in FIG. 6, an average COP (= COP_AVE) from the start of normal operation (heating operation) to the present time is calculated (step S103).

  As shown in FIG. 7, the defrosting start timing at which the one-cycle COP (= COP_CYCLE) becomes the highest is when the instantaneous COP (= COP) decreases to the one-cycle average COP (= COP_CYCLE) due to frost formation.

  The one-cycle average COP (= COP_CYCLE) when the defrosting operation is started at the present time is expressed by the following equation (2) using the average COP (= COP_AVE) from the start of the normal operation to the current time.

[Equation 2]
COP_CYCLE = C1 × COP_AVE (2)

  Here, as shown in FIG. 7, C1 on the right side of the formula (2) takes into account the decrease in average COP due to the defrosting operation. This C1 may be a preset constant. For example, when the 1-cycle average COP is 96% of the average COP (= COP_AVE) during the heating operation due to the defrosting operation, C1 = 0.96. Moreover, about C1, since the optimal value changes with a defrost system, the specification of an apparatus, etc., you may set the value used as an optimal value each time without setting it as a constant.

  The one-cycle average COP when the defrosting operation is started at the current time is calculated from the above equation (2) and compared with the current instantaneous COP (= COP) (step S104). If it is determined as a result of the comparison that the relationship shown in the following formula (3) is established (step S104; YES), the defrosting operation is started (step S105). On the other hand, if it is determined that the following expression (3) is not established (step S104; NO), the process returns to step S101 and the processing steps are repeated.

[Equation 3]
COP ≦ COP_CYCLE (3)

  However, in the above explanation, the frequency of the compressor 1 is constant, the temperature of the air flowing into the evaporator 4 (evaporator suction temperature) is constant, and the temperature of the air flowing into the condenser 2 (condenser suction temperature) is It holds for the case where it is constant. In practice, the frequency of the compressor 1, the temperature of the intake air of the evaporator 4 and the temperature of the intake air of the condenser 2 often change with time.

  When the frequency of the compressor 1, the temperature of the intake air of the evaporator 4 and the temperature of the intake air of the condenser 2 change, the condensation temperature Tc and the evaporation temperature Te change. For example, when the frequency of the compressor 1 increases, the difference between the condensation temperature Tc and the evaporation temperature Te increases, and the instantaneous COP in the equation (1) decreases. Further, when the temperature of the intake air of the condenser 2 rises, the condensation temperature Tc rises and the instantaneous COP of the equation (1) falls. Moreover, if the temperature of the suction air of the evaporator 4 falls, the evaporation temperature Te will fall and the instantaneous COP of Formula (1) will fall.

  In this way, when the frequency of the compressor 1, the temperature of the intake air of the evaporator 4 or the temperature of the intake air of the condenser 2 is changed, the instantaneous COP is reduced, and when the above formula (3) is satisfied, frost formation occurs. In spite of not doing, it will make a misjudgment and will start defrosting operation.

  Therefore, in order to avoid erroneous determination, in this embodiment, the corrected evaporation temperature and condensation temperature are calculated as follows. First, an evaporation temperature and a condensation temperature when operating at a predetermined reference compressor frequency F0, a reference evaporator suction air temperature Tae0, and a reference condenser suction air temperature Tac0 are set as a reference evaporation temperature Te0 and a reference condensation temperature Tc0. And

  Next, the compressor frequency detection means 15 detects the actual compressor frequency F. Further, the evaporator intake air temperature detecting means 13 detects the actual evaporator intake air temperature Tae. The condenser intake air temperature detection means 14 detects the actual condenser intake air temperature Tac. The evaporating temperature detecting means 12 detects the actual evaporating temperature Te. The condensation temperature detection means 11 detects the actual condensation temperature Tc. Based on the above detection values, the evaporating temperature when operating (heating operation) at the reference compressor frequency F0, the reference evaporator suction air temperature Tae0, and the reference condenser suction air temperature Tac0 in the current frosting state ( Correction evaporating temperature Te_mod) and condensing temperature (correcting condensing temperature Tc_mod).

  FIG. 9 is a diagram showing a relationship among the compressor frequency F, the evaporation temperature Te, and the condensation temperature Tc in the first embodiment of the present invention. Specifically, the evaporation temperature Te and the condensation temperature Tc are corrected according to the difference ΔF between the actual compressor frequency F and the reference compressor frequency F0. As shown in FIG. 9, when ΔF is positive, the condensation temperature Tc is decreased according to the absolute value of ΔF, and the evaporation temperature Te is corrected to be increased. On the contrary, when ΔF is negative, the condensation temperature Tc is increased according to the absolute value of ΔF, and the evaporation temperature Te is corrected to decrease. By doing so, it is possible to calculate the corrected evaporation temperature Te_mod and the corrected condensation temperature Tc_mod when the compressor 1 currently driven at the compressor frequency F is driven at the reference compressor frequency F0. Here, when control is performed so that the condensation temperature Tc does not change even if the compressor frequency F changes, the condensation temperature Tc and the corrected condensation temperature Tc_mod are the same. Further, when control is performed so that the evaporation temperature Te does not change even when the compressor frequency F changes, the evaporation temperature Te and the corrected evaporation temperature Te_mod are the same. For this reason, there is no need to perform correction, but here it is assumed that the correction is equivalent to the case where condensation temperature Tc = correction condensation temperature Tc_mod and evaporation temperature Te = correction evaporation temperature Te_mod (hereinafter, referred to as “condensation temperature Tc = correction condensation temperature T_mod” The same).

  FIG. 10 is a diagram showing the relationship between the evaporator intake air temperature Tae and the evaporation temperature Te in Embodiment 1 of the present invention. Further, the evaporation temperature Te is corrected according to the difference ΔTae between the actual evaporator intake air temperature Tae and the reference evaporator intake air temperature Tae0. As shown in FIG. 10, when ΔTae is positive, correction is made in a direction to lower the evaporation temperature Te according to the absolute value of ΔTae. On the other hand, when ΔTae is negative, correction is made to increase the evaporation temperature Te according to the absolute value of ΔTae. By doing in this way, correction | amendment evaporation temperature Te_mod when the evaporator suction air temperature Tae is the reference | standard evaporator suction air temperature Tae0 at the present time becomes computable.

  FIG. 11 is a diagram showing the relationship between the condenser intake air temperature Tac and the condensation temperature Tc in the first embodiment of the present invention. Further, the condensation temperature Tc is corrected according to the difference ΔTac between the actual condenser intake air temperature Tac and the reference condenser intake air temperature Tac0. As shown in FIG. 11, when ΔTac is positive, correction is made in the direction of decreasing the condensation temperature Tc according to the absolute value of ΔTac. On the contrary, when ΔTac is negative, the condensation temperature Tc is corrected in accordance with the absolute value of ΔTac. By doing so, the corrected condensing temperature Tc_mod when the condenser intake air temperature Tac is the reference condenser intake air temperature Tac0 at the present time can be calculated.

  As described above, the actual condensing temperature Tc and the evaporation temperature Te are corrected based on the compressor frequency F, the evaporator intake air temperature Tae, and the condenser intake air temperature Tac. Here, the condensation temperature Tc can be corrected based on the compressor frequency F and corrected based on the condenser intake air temperature Tac. In this embodiment, the compressor frequency F and the condenser intake air temperature Tac are used. Make corrections that reflect both. At this time, after performing correction based on the compressor frequency F, correction based on the condenser intake air temperature Tac may be performed, or correction may be performed in the reverse order. Similarly, the evaporation temperature Te can be corrected based on the compressor frequency F and corrected based on the evaporator intake air temperature Tae. In the present embodiment, the compressor frequency F and the evaporator intake air are corrected. Correction that reflects both of the temperatures Tae is performed. At this time, after performing correction based on the compressor frequency F, correction based on the evaporator intake air temperature Tae may be performed, or correction may be performed in the reverse order. By performing the correction, the instantaneous COP when operating at the reference compressor frequency F0, the reference evaporator intake air temperature Tae0, and the reference condenser intake air temperature Tac0 in the current frosting state is calculated based on the equation (4). can do.

[Equation 4]
Instant COP = (Tc_mod + 273.15)
/ (Tc_mod−Te_mod) (4)

  FIG. 12 is a view illustrating a flowchart of an example of a flow of processing relating to defrosting start determination control of the heat pump apparatus 100 according to Embodiment 1 of the present invention. Here, the process regarding control of the defrost start determination using Formula (4) is demonstrated.

  When the heat pump device 100 starts operation, the control device 50 uses the condensation temperature detection means 11 to condense temperature Tc, the evaporation temperature detection means 12 to evaporate temperature Te, the evaporator intake air temperature detection means 13 to Tae, and the condenser intake air temperature. Tac is detected by the detection means 14 (step S301). Then, based on each detected value, a corrected evaporation temperature Te_mod and a corrected condensing temperature Tc_mod are calculated (step S302). Further, based on the corrected evaporation temperature Te_mod and the corrected condensing temperature Tc_mod, the instantaneous COP (= COP) represented by the above equation (4) is calculated (step S303). Further, as shown in FIG. 6, an average COP (= COP_AVE) from the start of normal operation to the present time is calculated (step S304).

  As shown in FIG. 7, the defrosting start timing at which the one-cycle COP (= COP_CYCLE) becomes the highest is when the instantaneous COP (= COP) decreases to the one-cycle average COP (= COP_CYCLE) due to frost formation. Therefore, the one-cycle average COP is calculated based on the above equation (2) and compared with the current instantaneous COP (= COP) (step S305). As a result of the comparison, if it is determined that the relationship shown in Expression (3) is established (step 305; YES), the defrosting operation is started (step 306). On the other hand, if it is determined that the relationship shown in Expression (3) is not established (step S305; NO), the process returns to step S301 and the processing steps are repeated.

  The instantaneous COP shown in the equation (4) does not change depending on the compressor frequency F, the evaporator intake air temperature Tae, and the condenser intake air temperature Tac, and decreases only by frost formation. Therefore, the equations (2) to (4) Since the defrosting start timing is determined from the value calculated based on the above, the defrosting operation can be started at the optimum timing without erroneous determination. For this reason, 1-cycle average COP becomes high and can be connected to energy saving.

Embodiment 2. FIG.
In Embodiment 1 mentioned above, in order to avoid a misjudgment about the start timing of a defrost operation, it corrected with respect to the evaporation temperature Te or the condensation temperature Tc. In this embodiment, misjudgment is avoided without correcting the evaporation temperature Te or the condensation temperature Tc.

  For this reason, in this Embodiment, while the control apparatus 50 performs a defrost start determination process based on Formula (1) to Formula (3), it represents with following formula (5) from the compressor frequency F and the condensation temperature Tc. The determination based on the instantaneous heating capability (instant capability) Qh to be performed is also performed.

[Equation 5]
Qh = (Tc + 273.15) × F (5)

  FIG. 13 is a graph showing a relationship between the instantaneous heating capacity and the one-cycle average heating capacity in the second embodiment of the present invention. Based on FIG. 13, the relationship between the time and the capability (heating capability) of the heat pump apparatus 100 will be described. In FIG. 13, the horizontal axis represents time, and the vertical axis represents ability. When the frosting phenomenon in the evaporator 4 proceeds, the amount of heat exchange in the evaporator 4 decreases due to an increase in ventilation resistance and an increase in thermal resistance, and the instantaneous heating capacity Qh decreases as shown in FIG. By adding this decrease in the instantaneous heating capacity Qh to the defrosting start determination condition, it is possible to avoid erroneous determination even if the compressor frequency F, the evaporator intake air temperature Tae, and the condenser intake air temperature Tac change. Become.

  The determination is made based on a comparison between the one-cycle average heating capacity (average capacity) Qh_CYCLE and the instantaneous heating capacity Qh when the defrosting operation is started at the present time. Here, the one-cycle average heating capacity Qh_CYCLE is expressed as in Expression (6) using the average heating capacity Qh_AVE from the start of normal operation to the present time.

[Equation 6]
Qh_CYCLE = C2 × Qh_AVE (6)

  C2 on the right side of the above equation (6) takes into account the decrease in the average heating capacity Qh_AVE due to the defrosting operation as shown in FIG. This C2 may be a preset constant. For example, when the 1-cycle average heating capacity Qh_CYCLE becomes 96% of the average heating capacity Qh_AVE during the heating operation due to defrosting, C2 = 0.96. Moreover, about C2, since an optimal value changes with a defrosting system and the specification of an apparatus, you may set to the value used as an optimal value each time without setting it as a constant.

  FIG. 14 is a diagram showing temporal changes in instantaneous COP and heating capacity in the second embodiment of the present invention. In FIG. 14, the horizontal axis represents time, and the vertical axis represents COP and capability. When the frosting phenomenon in the evaporator 4 progresses, both the instantaneous COP and the instantaneous heating capacity decrease due to an increase in ventilation resistance and an increase in thermal resistance. At this time, when the compressor frequency F is increased, the condensation temperature Tc is increased and the evaporation temperature Te is decreased. Therefore, the instantaneous COP represented by the equation (1) is decreased, but the condensation temperature Tc and the compressor frequency are decreased. Since F increases together, the instantaneous heating capacity Qh expressed by the equation (5) increases.

  FIG. 15 is a diagram showing changes in instantaneous COP and heating capacity when the condenser intake air temperature Tac in the second embodiment of the present invention changes. In FIG. 15, the horizontal axis represents time, and the vertical axis represents COP and capability. When the frosting phenomenon in the evaporator 4 proceeds, both the instantaneous COP and the instantaneous heating capacity Qh are reduced due to the increase in the ventilation resistance and the increase in the thermal resistance. At this time, when the condenser intake air temperature Tac rises, the condensation temperature Tc rises, and in the instantaneous COP expressed by the formula (1), the denominator increase becomes larger than the numerator increase, and the decrease. To do. On the other hand, as the condensing temperature Tc increases, the instantaneous heating capacity Qh expressed by the equation (5) increases.

  FIG. 16 is a diagram showing changes in instantaneous COP and heating capacity when the evaporator intake air temperature Tae in the second embodiment of the present invention changes. In FIG. 16, the horizontal axis represents time, and the vertical axis represents COP and capability. When the frosting phenomenon in the evaporator 4 progresses, both the instantaneous COP and the instantaneous heating capacity decrease due to an increase in ventilation resistance and an increase in thermal resistance. At this time, when the evaporator intake air temperature Tae is decreased, the evaporation temperature Te is decreased. Therefore, the instantaneous COP represented by the equation (1) has a large denominator, and the instantaneous COP is decreased. On the other hand, the instantaneous heating capacity Qh represented by the equation (4) that does not include the evaporation temperature Te does not change.

  Thus, even when the instantaneous COP expressed by the equation (1) falls below the average COP as in the equation (3) at the time of the compressor frequency change, the evaporator intake air temperature change, and the condenser intake air temperature change, The instantaneous heating capacity Qh does not fall below the one-cycle average heating capacity Qh_CYCLE. For this reason, it turns out that it is not a COP fall by defrosting but a COP fall by a compressor frequency change, an evaporator intake air temperature change, or a condenser intake air temperature change.

  On the contrary, when the instantaneous COP (= COP) and the instantaneous heating capacity Qh decrease at the same time, it can be determined that it is due to frost formation. Therefore, the control device 50 determines that both the expression (3) and the following expression (7) When it is determined that it has been established, the defrosting operation is started.

[Equation 7]
Qh ≦ Qh_CYCLE (7)

  FIG. 17 is a view showing a flowchart of an example of a flow of processing relating to defrosting start determination control of the heat pump apparatus 100 according to Embodiment 2 of the present invention. When the heat pump device 100 starts operation, the control device 50 is detected by the compressor frequency F detected by the compressor frequency detection means 15, the condensation temperature Tc detected by the condensation temperature detection means 11, and the evaporation temperature detection means 12. Each value of the evaporation temperature Te is stored in the memory 51 (step S401). And the calculating part 52 calculates the instantaneous heating capability Qh represented by the instantaneous COP (= COP) represented by the said Formula (1) and Formula (5) (step S402).

  Thereafter, as shown in FIG. 6, an average COP (= COP_AVE) and an average heating capacity Qh_AVE from the start of normal operation to the present time are calculated (step S403).

  Next, the one-cycle average COP when the defrosting operation is started at the present time is calculated from the above equation (2), and the one-cycle average heating capacity is calculated from the above equation (6), and the current instantaneous COP (= COP) and The instantaneous heating capacity (= Qh) is compared (step S404). As a result of the comparison, if it is determined that the relationship of the above formulas (3) and (7) is established (step S404; YES), the defrosting operation is started (step S405). On the other hand, if it is determined that either of the above formulas (3) and (7) is not established (step S403; NO), the process returns to step S401, and the processing steps are repeated.

  The frosting phenomenon is the only factor that satisfies the relations of both the equations (3) and (7). Therefore, according to the heat pump device 100 of the present embodiment, the compressor frequency F, the evaporator suction air temperature Tae or the condenser suction is obtained by using the above formulas (3) and (7) for the defrosting start determination. Even when the air temperature Tac changes, the defrosting operation can be started at an optimal timing without erroneous determination, and energy saving can be achieved.

Embodiment 3 FIG.
In said Embodiment 1 and Embodiment 2, you may make it perform the correction which changes C1 and C2 according to the last defrost driving | operation. For example, the reference defrosting operation time is determined in advance, and when the previous defrosting operation time is longer than the reference defrosting operation time, the correction is performed so that C1 in Expression (2) or C2 in Expression (6) is increased. To do. On the other hand, when the last defrosting operation time is shorter than the reference defrosting operation time, C1 in Expression (2) or C2 in Expression (6) is corrected to be reduced.

  FIG. 18 is a diagram showing temporal changes in instantaneous COP and heating capacity in the third embodiment of the present invention. As shown in FIG. 18, the long defrosting time means that the COP and capacity reduction due to the defrosting operation is too large, and the heating operation time is too long. C2 in equation (6) should be increased.

  FIG. 19 is a diagram showing temporal changes in instantaneous COP and heating capacity according to Embodiment 3 of the present invention. As shown in FIG. 19, the short defrosting time means that the decrease in COP and capacity due to the defrosting operation is too small and the heating operation time is too short. C2 in Formula (6) is good to make small.

  As described above, by correcting C1 in formula (2) or C2 in formula (6), the calculation accuracy of the one-cycle average COP and the one-cycle average heating capacity can be improved. For this reason, the defrosting operation can be started at a more optimal timing, which leads to energy saving.

Embodiment 4 FIG.
In the first embodiment and the second embodiment described above, the evaporator suction air temperature Tae may be the evaporator suction air wet bulb temperature.

  In the first embodiment and the second embodiment, the condenser 2 exchanges heat between air and the refrigerant. However, the condenser 2 may exchange heat between the refrigerant and water, for example. In this case, the condenser intake air temperature Tac becomes the condenser inflow water temperature.

  In the first embodiment, the condensing temperature and the evaporating temperature are corrected based on all the detected values of the evaporator intake air temperature detecting means 13, the condenser intake air temperature detecting means 14, and the compressor frequency detecting means 15. However, the present invention is not limited to this. The present invention can be realized even when any of the above detection means is used.

  Further, in the second embodiment, the condensation temperature and the evaporation temperature are not corrected. However, as in the first embodiment, the corrected condensation temperature or the corrected evaporation temperature is calculated, and the corrected condensation temperature or the corrected evaporation temperature is obtained. Based on this, the instantaneous heating capacity Qh and the like may be calculated.

  DESCRIPTION OF SYMBOLS 1 Compressor, 2 Condenser, 3 Expansion device, 4 Evaporator, 5 Condenser fan, 6 Evaporator fan, 11 Condensation temperature detection means, 12 Evaporation temperature detection means, 13 Evaporator suction air temperature detection means, 14 Condenser Intake air temperature detection means, 15 compressor frequency detection means, 50 control device, 51 memory, 52 arithmetic unit, 100 heat pump device.

Claims (11)

A compressor, a condenser, an expansion device and an evaporator are connected by piping to form a refrigerant circuit,
Condensation temperature detection means for detecting the saturation temperature of the condenser as a condensation temperature;
Evaporating temperature detecting means for detecting the saturation temperature of the evaporator as an evaporating temperature;
Compressor frequency detection means for detecting a rotation frequency of the compressor as a compressor frequency;
A corrected condensing temperature and a corrected evaporating temperature are calculated based on the compressor frequency and the condensing temperature and the evaporating temperature, and an ability based on the corrected condensing temperature is calculated from a difference between the corrected condensing temperature and the corrected evaporating temperature. Calculate the current operating efficiency divided by power consumption, calculate at least the average operating efficiency from the start of operation to the end of defrosting when defrosting is performed at the current time, and the operating efficiency is less than the average operating efficiency A heat pump device comprising: a control device that performs a process of determining the start of defrosting of the evaporator when it is determined that the defrosting has occurred . The controller is
Based on the average of the operating efficiency of the OPERATION start to the current point, the heat pump apparatus according to claim 1 for calculating the average operating efficiency. The control device calculates a difference between the compressor frequency value and a predetermined reference compressor frequency value,
When the difference is positive, according to the absolute value of the difference, calculate the corrected evaporation temperature and the corrected condensation temperature to increase the evaporation temperature and decrease the condensation temperature,
3. The heat pump according to claim 2, wherein when the difference is negative, the corrected evaporation temperature and the corrected condensation temperature that lower the evaporation temperature and increase the condensation temperature are calculated according to an absolute value of the difference. apparatus. Further comprising an evaporator suction temperature detection means for detecting a temperature at which air flows into the evaporator as an evaporator suction temperature;
The control device calculates a difference between the value of the evaporator suction temperature and a value of a predetermined reference evaporator suction temperature,
If the difference is positive, according to the absolute value of the difference, calculate the corrected evaporation temperature to raise the evaporation temperature,
4. The heat pump device according to claim 2, wherein, when the difference is negative, the correction evaporation temperature that lowers the evaporation temperature is calculated according to an absolute value of the difference. A condenser suction temperature detecting means for detecting a temperature at which the fluid flows into the condenser as a condenser suction temperature;
The control device calculates a difference between the value of the condenser suction temperature and a predetermined reference condenser suction temperature,
If the difference is positive, according to the absolute value of the difference, calculate the corrected condensing temperature to lower the condensing temperature,
The heat pump device according to any one of claims 2 to 4, wherein when the difference is negative, the corrected condensing temperature is calculated so as to increase the condensing temperature according to an absolute value of the difference. A compressor, a condenser, an expansion device and an evaporator are connected by piping to form a refrigerant circuit,
Condensation temperature detection means for detecting the saturation temperature of the condenser as a condensation temperature;
Evaporating temperature detecting means for detecting the saturation temperature of the evaporator as an evaporating temperature;
Compressor frequency detection means for detecting a rotation frequency of the compressor as a compressor frequency;
Based on the condensation temperature and the evaporation temperature, at least the average operation efficiency from the start of operation to the end of the defrost when defrosting is performed at the present time, and based on the calculated average operation efficiency of the evaporator A control device that performs processing for determining the start of defrosting,
The controller is
Dividing the capacity based on the condensing temperature by the power consumption calculated from the difference between the condensing temperature and the evaporating temperature to calculate the current operating efficiency, and from the condensing temperature and the compressor frequency in the condenser The average operating efficiency from the start of operation to the end of defrosting is calculated based on the average of the operating efficiency from the start of operation to the current time and the average of the capacity, when defrosting is performed at the current time. and calculates the average power, the operation when efficiency is determined that the average operating efficiency or less and the capacity is below the average capacity, the evaporator line cormorants heat pump apparatus a process of starting the defrosting of. The controller is
The heat pump device according to claim 6, wherein the average capacity is corrected based on a difference between a defrosting operation time performed last time and a preset reference defrosting operation time. The controller is
Calculate the difference between the previous defrost operation time and the reference defrost operation time,
When the difference is positive, according to the absolute value of the difference, perform correction to increase the average ability,
The heat pump apparatus according to claim 7, wherein when the difference is negative , correction is performed so that the average ability is lowered according to an absolute value of the difference. The controller is
The heat pump apparatus as described in any one of Claims 1-8 which correct | amends the said average operation efficiency based on the difference of the defrost operation time performed last time and the reference | standard defrost operation time set beforehand. The controller is
Calculate the difference between the previous defrost operation time and the reference defrost operation time,
When the difference is positive, according to the absolute value of the difference, perform a correction that increases the average operating efficiency,
The heat pump apparatus according to claim 9, wherein when the difference is negative , correction is performed so that the average operation efficiency is lowered according to an absolute value of the difference.   The air conditioning system which performs air conditioning of object space using the heat pump apparatus as described in any one of Claims 1-10.

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