JP2011052838A - Refrigerating air conditioning device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To properly control the operating capacity of a compressor, the degree of supercooling at an outlet of a condenser, and the degree of superheating at an outlet of an evaporator, according to operating conditions. <P>SOLUTION: This refrigerating air-conditioning device is composed of a plurality of refrigerating cycles 2, utilizes a liquid medium on a heat source side and a load side, and supplies cold/heat to the load side by heating/cooling a heat medium. A total value of the compressor operating capacities of the refrigerating cycles, and the degree of supercooling of the outlet of the condenser and the degree of superheating of the outlet of the evaporator, are controlled to keep temperature difference between a load-side heat medium inflow temperature of a load-side heat exchanger of the refrigerating cycle positioned in the most upstream to a flow channel of the load-side heat medium and a load-side heat medium outflow temperature of the load-side heat exchanger of the refrigerating cycle positioned in the most downstream to the flow channel of the load-side heat medium, at a prescribed value. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a refrigeration air conditioner, and more particularly to a refrigeration air conditioner that uses liquid media such as water and brine on a heat source side and a load side, and supplies cold and hot heat to the load side by heating and cooling the heat medium.

Conventionally, as this type of apparatus, for example, two heat pump water heaters configured with a refrigeration cycle comprising a compressor, a condenser, a heating heat exchanger, an expansion mechanism, and an evaporator are provided, and the condensers of two heat pump water heaters Has been proposed in which the condensing temperature is increased stepwise along the flow direction of the fluid to be heated (see, for example, Patent Document 1). reference).
In such a thing, since the condensation temperature of an upstream heat pump water heater can be lowered | hung, it is supposed that it can drive | operate with high efficiency compared with the heat pump water heater comprised with the single refrigerating cycle.

In addition, as an example of a refrigeration air conditioner that supplies cold and hot heat, a plurality of refrigeration cycles including a compressor, a condenser, an expansion valve, and an evaporator are provided, and each evaporator is connected in series to a circuit of a fluid to be cooled. Thus, there has been proposed one in which the evaporation temperature of each refrigeration cycle is lowered stepwise along the flow direction of the fluid to be cooled (see, for example, Patent Document 2).
In such a case, for example, when chilled water having a large temperature difference is cooled in stages as the fluid to be cooled, the evaporation temperature of the evaporator of each refrigeration cycle can be set in order from the flow direction of the chilled water. It is said that it can drive.

Japanese Patent No. 3987990 (FIGS. 5 and 6) JP 2006-329601 A (FIG. 1)

  However, by connecting the condensers of the two heat pump water heaters in series with the circuit of the fluid to be heated, the condensation temperature is increased stepwise along the flow direction of the fluid to be heated. If so, how can the compressor operating capacity of each heat pump water heater be controlled to achieve high-efficiency operation, and what if the evaporator-side heat medium that is the heat source is connected in series? In fact, there is no consideration about the fact that it is impossible to realize high-efficiency operation according to the load and operating conditions.

  In addition, by connecting the evaporators of a plurality of refrigeration cycles in series with the circuit of the fluid to be cooled, the evaporation temperature of each refrigeration cycle decreases stepwise along the flow direction of the fluid to be cooled. The compressor capacity of each refrigeration cycle is controlled by an inverter based on the outside air temperature and the refrigerant pressure, but the capacity of each compressor with respect to operating conditions such as evaporator outlet superheat However, there is no consideration on how to control high-efficiency operation, and the fact is that high-efficiency operation according to load and operating conditions cannot be realized.

  In view of the above, the present invention is a refrigeration air conditioner configured by a plurality of refrigeration cycles, using a liquid medium on a heat source side and a load side, and heating / cooling the heat medium to supply cold / hot heat to the load side. Therefore, it is an object of the present invention to appropriately control the operation capacity of the compressor and the degree of supercooling of the condenser outlet and the degree of superheat of the evaporator outlet in accordance with the operating conditions.

  The refrigeration air conditioner according to the present invention includes a plurality of refrigeration cycles configured by annularly connecting a compressor having a variable operating capacity, a heat source side heat exchanger, a pressure reducing device, and a load side heat exchanger, The heat source side heat exchanger of each refrigeration cycle is configured to radiate or absorb heat to the heat source side heat medium, and the flow path of the heat source side heat medium is configured to flow in series through the heat source side heat exchanger of each refrigeration cycle. The load-side heat exchanger is configured to cool or heat the load-side heat medium and supply cold / heat, and the flow path of the load-side heat medium flows in series through the load-side heat exchanger of each refrigeration cycle, The load-side heat medium inflow temperature of the load-side heat exchanger of the refrigeration cycle positioned upstream with respect to the flow path of the load-side heat medium and the load of the refrigeration cycle positioned downstream of the load-side heat medium flow path Detects the load side heat medium outflow temperature of the side heat exchanger And a control device that controls the total value of the compressor operating capacity of each refrigeration cycle so that the temperature difference between the load-side heat medium inflow temperature and the load-side heat medium outflow temperature becomes a predetermined value. And.

  According to the refrigerating and air-conditioning apparatus of the present invention, the load-side heat medium inflow temperature of the load-side heat exchanger of the refrigeration cycle located in the uppermost stream with respect to the flow path of the load-side heat medium and the flow path of the load-side heat medium On the other hand, since the total value of the compressor operating capacity of each refrigeration cycle is controlled so that the temperature difference between the load side heat medium outflow temperature of the load side heat exchanger of the refrigeration cycle located on the most downstream side becomes a predetermined value. Even with a plurality of refrigeration cycles, the load side heat medium outflow temperature can be adjusted to the target water temperature set by the user of the refrigeration air conditioner with a simple heat medium temperature detecting means, and each refrigeration cycle However, it is possible to cover the heat load in a well-balanced manner, increasing the operating efficiency of the entire apparatus and obtaining a highly efficient refrigeration air conditioner.

It is a refrigerant circuit diagram of the refrigerating and air-conditioning apparatus according to Embodiment 1 of the present invention. It is a Mollier diagram of the refrigerating and air-conditioning apparatus according to Embodiment 1 of the present invention. It is a figure which shows the temperature state of the heat-source side water heat exchanger and load side water heat exchanger of the refrigerating air-conditioning apparatus which concerns on Embodiment 1 of this invention. It is a flowchart which shows the control action of the refrigerating air-conditioning apparatus which concerns on Embodiment 1 of this invention. It is a figure which shows the control characteristic of the refrigerating air conditioner which concerns on Embodiment 1 of this invention. It is a figure which shows the control characteristic of the refrigerating air conditioner which concerns on Embodiment 1 of this invention. It is a figure which shows the control characteristic of the refrigerating air conditioner which concerns on Embodiment 1 of this invention. It is a circuit diagram of the refrigerating and air-conditioning apparatus according to Embodiment 1 of the present invention. It is a circuit diagram of the refrigerating and air-conditioning apparatus according to Embodiment 1 of the present invention. It is a figure which shows the difference with the refrigeration air conditioning apparatus which concerns on Embodiment 1 of this invention, and the conventional refrigeration cycle. It is a refrigerant circuit diagram of the refrigerating and air-conditioning apparatus according to Embodiment 1 of the present invention. It is a figure which shows the characteristic of the refrigerating air conditioner which concerns on Embodiment 1 of this invention. It is a refrigerant circuit diagram of the refrigerating and air-conditioning apparatus according to Embodiment 2 of the present invention. It is a Mollier diagram of the refrigerating and air-conditioning apparatus according to Embodiment 2 of the present invention. It is a figure which shows the relationship between the evaporator exit superheat degree and COP of the refrigerating air conditioning apparatus which concerns on Embodiment 2 of this invention. It is a figure which shows the form of the internal heat exchanger used with the refrigerating air conditioning apparatus which concerns on Embodiment 2 of this invention. It is a refrigerant circuit diagram of the refrigerating and air-conditioning apparatus according to Embodiment 3 of the present invention.

Embodiment 1 FIG.
A first embodiment of the present invention is shown in FIG. FIG. 1 is a refrigerant circuit diagram of the refrigerating and air-conditioning apparatus of the present invention. A refrigeration cycle 2a, 2b having the same circuit configuration is mounted in a heat source machine 1 which is a refrigeration air conditioner. The refrigeration cycle 2a includes a compressor 3a, a heat source side water heat exchanger 4a that is a heat source side heat exchanger, an expansion valve 5a that is a pressure reducing device, and a load side water heat exchanger 6a that is a load side heat exchanger. As shown in the figure, the refrigerant circuit is configured in an annular connection. Similarly, the refrigeration cycle 2b also includes a compressor 3b, a heat source side water heat exchanger 4b, an expansion valve 5b, and a load side water heat exchanger 5b, which are connected in an annular shape as shown. A refrigerant circuit is configured. In the following description, for example, when the refrigeration cycles 2a and 2b are collectively referred to as the refrigeration cycle 2, the same applies to other devices and other embodiments. The heat exchanger 4, the expansion valve 5, and the load-side water heat exchanger 6 are called respectively.

  As the refrigerant circulating in the refrigeration cycle 2, R410A which is a pseudo azeotropic refrigerant mixture is used. The compressor 3 is capacity-controlled by controlling the number of revolutions by an inverter (not shown), and is constituted by, for example, a scroll compressor equipped with a DC brushless motor. The heat source side water heat exchanger 4 and the load side water heat exchanger 6 are configured by plate heat exchangers, and perform heat exchange between the heat medium and the refrigerant. The expansion valve 5 is composed of an electronic expansion valve whose opening degree is variably controlled. The refrigerant circuit is connected in a ring shape, and the refrigerant flows in the order of the compressor 3, the heat source side water heat exchanger 4, the expansion valve 5, and the load side water heat exchanger 6. The heat-source-side water heat exchanger 4 and the load-side water-heat exchanger 6 constitute a heat medium flow path so that the heat medium and the refrigerant that circulate each flow countercurrently. Here, examples of the heat medium include water and brine.

  In the refrigeration cycle 2, refrigerant pressure detectors 23 a and 23 c are provided on the discharge side of the compressor 3, and refrigerant pressure detectors 23 b and 23 d are provided on the suction side of the compressor 3. measure. Further, the heat medium temperature detectors 21 a and 21 c are disposed on the load side heat medium inflow side of the load side water heat exchanger 6, and the heat medium temperature detectors 21 b and 21 d are disposed on the load side heat medium outflow side of the load side water heat exchanger 6. Are provided to detect the temperature of the heat medium at each set location. Furthermore, the heat medium temperature detectors 21e and 21g are arranged on the heat source side heat medium inflow side of the heat source side water heat exchanger 5, and the heat medium temperature detectors 21f and 21h are arranged on the heat source side heat medium outflow side of the heat source side water heat exchanger 5. Are provided to detect the temperature of the heat medium at each set location. Furthermore, refrigerant temperature detectors 22a and 22c are provided on the discharge side of the compressor 3, refrigerant temperature detectors 22b and 22d are provided on the suction side of the compressor 3, and refrigerant temperature detection is provided on the refrigerant outflow side of the heat source side water heat exchanger 4. Containers 22e and 22f are provided to detect the refrigerant temperature at the installation location. In the following description, the heat medium temperature detector is generically referred to as the heat medium temperature detector 21, the refrigerant temperature detector is generically referred to as the refrigerant temperature detector 22, and the refrigerant pressure detector is generically referred to as the refrigerant pressure. Each detector will be referred to as a detector 23.

  The refrigeration cycles 2a and 2b are configured such that the load-side water heat exchanger 6 is in series with the load-side heat medium circuit 51a, and the heat-source-side water heat exchanger 4 is connected to the heat-source-side heat medium circuit 51b. It is configured to be in series. Further, the load-side heat medium circuit 51a is arranged so that the inlet is on the refrigeration cycle 2a side and the outlet is on the refrigeration cycle 2b side, and the heat source-side heat medium circuit 51b is on the refrigeration cycle 2b side. Each outlet is configured to be on the refrigeration cycle 2a side.

  Next, the operation | movement operation | movement in this refrigeration air conditioner is demonstrated using FIG. 2 and FIG.

  First, the refrigerant circuit operation will be described. Since the operation of the refrigeration cycle is the same as that of the refrigeration cycles 2a and 2b, the refrigeration cycle 2a will be described as a representative. The high-temperature and high-pressure gas refrigerant (A1) discharged from the compressor 3a flows into the heat source side water heat exchanger 4a, and is condensed and liquefied by releasing heat to the cooling water that is the heat source side heat medium (B1). The high-pressure liquid refrigerant that has flowed out of the heat-source-side water heat exchanger 4a is decompressed by the expansion valve 5a, becomes a low-pressure two-phase refrigerant, and flows into the load-side water heat exchanger 6a (C1). The load-side water heat exchanger 6a evaporates and gasifies by absorbing heat from the cold water that is the load-side heat medium (D1), cools the water, and generates cold water. The low-pressure gas refrigerant that has flowed out of the load-side water heat exchanger 6a is sucked into the compressor 3a.

  Next, operations of the heat source side heat medium circuit 51b and the load side heat medium circuit 51a will be described. Cooling water and cold water are conveyed by water pumps 31b and 31a.

  First, the operation of the heat source side heat medium circuit 51b will be described. For example, the cooling water at 35 ° C. that is the heat source side heat medium flows into a heat source side device (not shown) such as a cooling tower and drops to 30 ° C., for example, and then the heat source side water of the heat source unit 1, that is, the refrigeration cycle 2b. It flows into the heat exchanger 4b. The cooling water that has flowed into the heat source unit 1 is heated by the refrigerant of the heat source side water heat exchanger 6b and the temperature rises, for example, flows out to 32.5 ° C., and then flows out, and then the heat source side water heat exchanger 4a of the refrigeration cycle 2a. Flow into. Again, the cooling water is heated by the refrigerant, and the temperature further rises, for example, 35 ° C. and flows out of the heat source unit 1. Thereafter, the cooling water again flows into the heat source side device. The condensation temperature of the refrigeration cycle 2 is higher at the downstream of the heat source side flow path, and the condensation temperature of the refrigeration cycle 2b is lower as it is positioned upstream of the heat source side heat medium circuit.

  Next, the operation of the load side heat medium circuit 51a will be described. For example, cold water of 7 ° C., which is a load-side heat medium, flows into a load-side device (not shown) such as a fan coil and rises to, for example, 12 ° C., and then the load of the heat source unit 1, specifically the refrigeration cycle 2a. It flows into the side water heat exchanger 6a. The cold water that has flowed into the heat source unit 1 is cooled by the refrigerant of the load-side water heat exchanger 6a and the temperature thereof drops, for example, becomes 9.5 ° C., then flows out, and then flows to the load-side water heat exchanger 6b of the refrigeration cycle 2b. Inflow. Again, the cold water is cooled by the refrigerant, and the temperature further decreases, for example, reaches 7 ° C. and flows out of the heat source unit 1. Thereafter, the cold water flows into the load side device again. At this time, the evaporating temperature of the refrigeration cycle 2 becomes lower as the downstream side of the load side flow path.

  Next, the control operation of this refrigeration air conditioner will be described based on the flowchart of FIG. Since the operation of the refrigeration cycle 2 is common to the refrigeration cycles 2a and 2b, only the refrigeration cycle 2a will be described here. First, when the heat source device 1 starts operation, the control device 41 performs initial setting. That is, the target outlet water temperature of cold water set by the user of the refrigeration air conditioner, the flow rates of the water pumps 31b and 31a of the heat source side device and the load side device, and the heat medium temperature supplied from the heat source side device to the heat source unit 1 From the cooling water inlet water temperature detected by the detector 21g, the cold water inlet water temperature detected by the heat medium temperature detector 21a supplied from the load side device to the heat source unit 1, and the like, the rotational speed of the compressor 3a and the opening of the expansion valve 5a Is set (step S1). After starting operation in this state, each actuator is automatically controlled according to the operation state, and the rotation speed of the compressor 3a is determined based on a fixed value or a difference between the cold water inlet temperature and the target value, and the expansion valve is opened. The degree is determined based on the heat source inlet water temperature and the cold water inlet water temperature.

  The total operating capacity of the compressor 3 is the difference between the cold water inlet water temperature detected by the heat medium temperature detector 21a, the target value set by the load side device, and the load side water heat exchangers of the refrigeration cycles 2a and 2b. It is determined according to the capacity. For example, if the load-side water heat exchangers 6a and 6b have the same capacity, half of the amount of heat to be processed by the load-side water heat exchanger 6 may be distributed to the refrigeration cycles 2a and 2b and processed. The operation capacities of 3a and compressor 3b are set to be equal to each other.

  At this time, if the total operating capacity of the compressor 3 is larger than the load, the chilled water outlet water temperature decreases, and conversely, if the total operating capacity is smaller than the load, the chilled water outlet water temperature increases. Therefore, the total operating capacity of the compressor 3 is controlled based on the cold water outlet water temperature.

  That is, it is determined whether or not the cold water outlet water temperature is a set value (set temperature) (step S2). If it is determined that the cold water outlet water temperature is the set temperature, the process proceeds to step S6. If it is determined in step S2 that the chilled water outlet water temperature is not the set value, then it is checked whether or not the chilled water outlet water temperature is lower than the set temperature (step S3), and if the chilled water outlet water temperature is lower than the set temperature. If it is determined, the total compressor operating capacity is reduced (step S4), and then the process proceeds to step S6.

  Further, if it is determined in step S3 that the chilled water outlet water temperature is not lower than the set temperature, it is determined that the chilled water outlet water temperature is higher than the set temperature and the total compressor operating capacity is increased (step S5), and then the processing is performed. To step S6.

  The operating capacities of the compressors 3a and 3b are changed by increasing or decreasing the rotational speed, the rotational speed is increased when the operating capacity is increased, and the rotational speed is decreased when the operating capacity is decreased. Thereby, the target operating capacity is realized.

  In step S6, it is determined whether or not the condensation temperature converted from the pressure detected by the pressure detector 23a or 23c of the refrigeration cycle 2 is within the operation range of the heat source unit 1. If it is determined in step S6 that the condensation temperature is within the operating range of the heat source unit 1, the process proceeds to step S10. If it is determined in step S6 that the condensing temperature is not within the operating range of the heat source unit 1, then it is checked whether the condensing temperature exceeds the upper limit (step S7), and the condensing temperature exceeds the upper limit. If it is determined that the operating capacity of the compressor 3 of the corresponding refrigeration cycle 2 is decreased and the operating capacity of the compressor 3 of the other refrigeration cycle 2 is increased (step S8), the process proceeds to step S10. .

  If it is determined in step S7 that the condensing temperature does not exceed the upper limit value, it is determined that the condensing temperature is lower than the lower limit value, and the operating capacity of the compressor 3 of the corresponding refrigeration cycle 2 is increased. After reducing the operating capacity of the compressor 3 of the refrigeration cycle 2 (step S9), the process proceeds to step S10.

  Thereby, it is possible to suppress an increase in the condensation temperature while keeping the total compressor operating capacity constant.

  In step S10, the refrigerant superheat degree SH at the outlet of the load-side water heat exchanger 6 acting as an evaporator is calculated, and it is determined whether or not the refrigerant superheat degree SH is a target set value (eg, 3 ° C.). Here, the refrigerant superheat degree SH at the outlet of the load-side water heat exchanger 6 is obtained by calculating the saturation gas temperature from the value detected by the refrigerant temperature detector 22b and the value detected by the pressure detector 23b on the suction side of the compressor 3. A value calculated by the difference between the calculated value and the calculated value is used. If the opening degree of the expansion valve 5 is small, the flow rate of the refrigerant flowing through the load-side water heat exchanger 6 decreases, so the refrigerant superheat degree SH at the outlet of the load-side water heat exchanger increases, and conversely the opening degree of the expansion valve 5 increases. If larger, the refrigerant superheat degree SH at the outlet of the load side water heat exchanger becomes smaller. If it is determined in step S10 that the refrigerant superheat degree SH (hereinafter referred to as intake SH) at the outlet of the load-side water heat exchanger is a set value, the process returns to step S2.

  If it is determined in step S10 that the inhalation SH is not the set value (3 ° C.), it is next determined whether or not the inhalation SH has exceeded the set value (3 ° C.) (step S11). If it is determined that the temperature has exceeded (3 ° C.), the opening degree of the expansion valve 5 is increased (step S12), and the process returns to step S2.

  If it is determined in step S11 that the suction SH does not exceed the set value (3 ° C.), the opening of the expansion valve 5 is reduced (step S13), and the process returns to step S2.

  Thereby, the refrigerant | coolant superheat degree SH (suction | inhalation SH) of the target load side water heat exchanger exit is realizable.

  Next, the relationship between the total capacity of the compressor 3 (total compressor operating capacity), the operating capacity of the compressors 3a and 3b, and the operating efficiency will be described with reference to FIG. FIG. 5 is a diagram showing characteristics when the refrigeration cycles 2a and 2b have the same specifications and configuration, and the heat source apparatus 1 performs an operation of cooling the load-side heat medium. The horizontal axis of the figure shows the capacity ratio of the compressors 3a and 3b. When the capacities of the compressors 3a and 3b coincide, the compressor capacity ratio is 100%. COP indicates the operation efficiency of the heat source unit 1, the cooling capacity of the heat source unit 1 (= total value of the capacities of the load-side water heat exchangers 2a and 2b), and the total input of the heat source unit 1 (compressors 3a and 3b and The ratio of the electric power of the actuator and the control device 41). The COP ratio is a COP ratio based on the COP when the compressor capacity ratio is 100%. The compressor rotational speed ratio indicates the rotational speed ratio of each compressor based on the rotational speed of the compressors 3a and 3b when the compressor capacity ratio is 100%. The total capacity indicates a value obtained by dividing the total rotational speed of the compressors 3a and 3b by the rotational speed when the compressor capacity ratio is 100%.

  As shown in FIG. 5, when the compressor capacity ratio is 100%, the COP ratio is 100%. That is, the operating efficiency is maximized when the rotation speeds of the compressors 3a and 3b are the same. Further, if the compressor operating capacity ratio is between 90% and 110%, the COP ratio is within -1%. If the operating capacity ratio is within this range, highly efficient operation is possible.

  FIG. 6 shows the relationship between the average condensation temperature, average evaporation temperature and compressor operating capacity ratio of the refrigeration cycles 2a and 2b of this embodiment and the average value of the compressor efficiency of the compressors 3a and 3b. The compressor efficiency is determined by the condensation temperature, evaporation temperature, and compressor speed. Here, the compressor efficiency uses a weighted average value considering the capacity ratio of the refrigeration cycles 2a and 2b with respect to the full capacity. When the compressor capacity ratio at which the COP ratio is maximized is 100%, the average compressor efficiency is also maximized. That is, if the compressor operating capacity ratio is determined so as to maximize the average compressor efficiency from the current condensing temperature and evaporation temperature, highly efficient operation can be performed.

  FIG. 7 shows the relationship between the compressor capacity ratio and the cooling capacity ratio of the refrigeration cycles 2 a and 2 b with respect to the cooling capacity of the heat source apparatus 1. When the compressor capacity ratio at which the COP ratio is maximum is 100%, the cooling capacity ratio of the refrigeration cycle 2a is 52.7%, the cooling capacity ratio of the refrigeration cycle 2b is 47.3%, and the cooling capacity of the refrigeration cycle 2a is refrigeration. It becomes larger than cycle 2b. This is because the refrigerant flow rate increases because the evaporation temperature of the refrigeration cycle 2a on the upstream side of the load-side heat medium circuit is higher than that of the refrigeration cycle 2b, as shown in FIG.

  In the present embodiment, the heat source side water heat exchanger 4 is connected in series to the heat source side flow path, and the load side water heat exchanger 5 is connected in series to the load side flow path. The effect of connecting the heat exchangers in series will be described taking the heat source side as an example. FIG. 8 shows a condition where the cooling water inlet temperature of the heat source unit 1 is 30 ° C. and the outlet temperature is 35 ° C., and there is only one heat source side water heat exchanger 4 (one condensing circuit). It is the figure showing the characteristic of the temperature difference of the cooling water and refrigerant | coolant in a heat exchanger when the heat source side water heat exchanger 4 is arrange | positioned in series (2 condensation circuit). The temperature change in the two-condensing circuit in this case is expressed as shown in FIG. 3, the refrigeration cycle 2b is operated at the condensation temperature CTb, and the refrigeration cycle 2a is operated at the condensation temperature CTa. The temperature difference is ΔCTb and ΔCTa. For example, when the temperature difference with the cooling water inlet / outlet temperature in each heat source side water heat exchanger 4 is controlled similarly, ΔCTb = ΔCTa. At this time, since the cooling water inlet / outlet temperature of the heat source side water heat exchanger 4a is 2.5 ° C. higher than that of the heat source side water heat exchanger 4b, the condensation temperature CTa of the refrigeration cycle 2a is 2. 5 ° C higher.

The horizontal axis in FIG. 8 represents the refrigerant condensing temperature, and in the two condensing circuit, the average value of each refrigeration cycle 2 (CTa + CTb) / 2. The vertical axis temperature difference in the graph (A) of FIG. 8 represents the logarithm average temperature difference between the cooling water and the refrigerant condensing temperature, and in the case of one condensing circuit, the temperature difference = (cooling water outlet temperature 35 ° C.−cold water inlet temperature). 30 ° C.) / Ln {(refrigerant condensation temperature−cold water inlet temperature 30 ° C.) / (Refrigerant condensation temperature−cooling water outlet temperature 35 ° C.)}. In the case of the two-condensing circuit, the temperature difference of the refrigeration cycle 2a = (cooling water outlet temperature 35 ° C.−cooling water inlet temperature 32.5 ° C.) / Ln {(refrigerant condensing temperature CTa−cold water inlet temperature 32.5 ° C.) / ( Refrigerant condensing temperature CTa−cooling water outlet temperature 35 ° C.)} and refrigeration cycle 2b temperature difference = (cooling water outlet temperature 32.5 ° C.−cooling water inlet temperature 30 ° C.) / Ln {(refrigerant condensing temperature CTb−cold water inlet) Temperature 30 ° C.) / (Refrigerant condensation temperature CTb−cooling water outlet temperature 2.5 ° C.)}.
The vertical axis temperature difference in the graph (B) of FIG. 8 represents the difference between the temperature difference of the two condensation circuits and the temperature difference of the one condensation circuit obtained as described above.

  As shown in FIG. 8, the temperature difference between the cooling water and the refrigerant condensing temperature is larger in the two condensing circuit than in the one condensing circuit, and the heat exchange amount in the two condensing circuit is increased accordingly. In the case of performing the operation with the same heat exchange amount, the condensing temperature can be lowered in the 2 condensing circuit than in the 1 condensing circuit, and thus the operation can be performed with higher efficiency. Further, the temperature difference increase width of the two condensing circuit is increased as the refrigerant condensing temperature is lower. That is, the effect of the two condensing circuit is increased under the condition that the average condensing temperature is lower than that of one condensing and the operating condition where the heat source side inlet / outlet temperature difference is large.

  Up to this point, the effect of connecting the heat exchangers in series has been described by taking the case of the heat source side heat exchanger as an example, but the same effect can be obtained with a load side water heat exchanger used as an evaporator.

  Next, the effect under the condition in which the heat source and the load side temperature difference are enlarged will be described. First, the heat source side inlet / outlet temperature difference will be described. When the cooling tower, which is the heat source side device, is sufficiently larger than the heat source unit 1, the temperature of the water flowing out of the cooling tower is almost the same as the outside air. Therefore, the temperature of the heat medium flowing into the heat source unit 1 is constant. Become. FIG. 9 shows the relationship between the COP and the average condensing temperature when the heat source side temperature difference is increased, that is, the outlet water temperature is increased under the condition that the load side heat medium circuit inlet / outlet temperature difference is constant. The horizontal axis indicates the difference between the inflow and outflow temperatures of the heat source side water heat exchanger 4, and the COP ratio indicates a value based on the COP when the inlet / outlet temperature difference is 5 ° C. The average condensation temperature of 2 condensation indicates the arithmetic average value of the condensation temperatures of the refrigeration cycles 2a and 2b.

  Although the COP ratio decreases as the temperature difference on the heat source side increases, the COP ratio of the two condensing circuit is higher than that of the one condensing circuit, and the COP difference also increases. This is because the average condensation temperature is lowered and the input of the heat source unit 1 is lowered. As described above, since the COP drop due to the temperature difference expansion can be suppressed in the two-condensing circuit, the operation can be performed more efficiently than the single condensation.

  Next, the influence of the load side inlet / outlet temperature difference will be described. Since the load-side outlet water temperature is determined by the refrigeration air conditioner installer, the heat source unit 1 is controlled so that the outlet water temperature is constant. FIG. 10 shows the relationship between COP and average evaporation temperature when the heat source side heat medium circuit inlet / outlet temperature difference is constant and the load side inlet water temperature is changed to increase the load side temperature difference. The horizontal axis and the COP ratio are the same as in the heat source side example, and the average evaporation temperature of two evaporations indicates the arithmetic average value of the evaporation temperatures of the refrigeration cycles 2a and 2b.

  Although the COP is improved as the load side temperature difference is increased, the COP of the two evaporation circuit is higher than that of the one evaporation circuit, and the difference of the COP is also increased. This is because the input of the heat source device 1 decreases because the average evaporation temperature increases. As described above, in the two evaporation circuit, the COP is improved by the temperature difference expansion, so that the operation can be performed more efficiently than the one evaporation circuit.

  In order to realize this operation, capacity control of the compressor by the inverter is essential, and conversely, capacity control by the inverter compressor and the heat exchanger of the heat source side heat medium circuit and the load side heat medium circuit are connected in series. By connecting, the effects of 2 condensation and 2 evaporation can be obtained at the same time, so that operation with remarkably high efficiency is possible as compared with the 1 condensation and 1 evaporation circuit.

  As in the present embodiment, a plurality of refrigeration cycles 2 equipped with a compressor 3 having a variable operating capacity are provided, and a heat source side water heat exchanger 4 and a load side water heat exchanger 6 are respectively connected to a heat source side heat medium circuit and a load. When connecting in series with the side heat medium circuit, the load side outflow temperature can be matched with the target value by determining the total operating capacity of the compressor 3 from the difference between the load side inflow temperature and the outflow temperature.

  In this embodiment, the load side heat medium circuit inlet is on the refrigeration cycle 2a side and the heat source side heat medium circuit inlet is on the refrigeration cycle 2b side, but the heat source side heat medium circuit inlet may be on the refrigeration cycle 2a side. Since the refrigeration cycle 2a has a large cooling capacity, when the heat source side inlet temperature is the same, the condensation temperature is more likely to rise than the refrigeration cycle 2b. Therefore, by providing the heat source side heat medium circuit inlet on the refrigeration cycle 2a side, an increase in the condensation temperature of the refrigeration cycle 2a can be suppressed.

  Further, by determining the capacity ratio of the compressor 3 of each refrigeration cycle 2 according to the load-side heat exchanger capacity and the compressor rated capacity, it is possible to realize highly efficient operation.

  Further, the operating capacity of the compressor 3 is determined so that the average compressor efficiency obtained from the condensing temperature, the evaporating temperature, the compressor rotation speed of each refrigeration cycle 2 and the inlet / outlet temperature difference of each load-side water heat exchanger 6 is maximized. By doing so, highly efficient operation can be realized.

  Moreover, even when the heat source side water flow rate decreases and the temperature difference between the inlet and outlet of the heat source side heat medium circuit increases, it is possible to suppress a decrease in operation efficiency. On the other hand, when the load-side outlet water temperature is operated at a constant level, a highly efficient operation can be realized by increasing the load-side inlet / outlet temperature difference. Due to these synergistic effects, it is possible to realize an operation that is always more efficient than a normal circuit regardless of the heat source and the load side temperature difference.

  Also, since the condensation temperature tends to rise in the refrigeration cycle downstream of the heat source side heat medium circuit, when the condensation temperature exceeds the specified value, the compressor capacity of the corresponding refrigeration cycle is reduced to suppress the condensation temperature rise. can do. Then, by increasing the compressor operating capacity of the refrigeration cycle with a low condensing temperature so that the total operating capacity matches, the chilled water outlet temperature can be stabilized at the target value even when the condensing temperature exceeds a predetermined value. Can do.

  Further, since the evaporating temperature of the refrigeration cycle upstream of the load side heat medium circuit is likely to increase, the evaporating temperature can be increased by increasing the compressor capacity of the corresponding refrigeration cycle 2 when the evaporating temperature exceeds a predetermined value. The rise can be suppressed. Then, by reducing the compressor operating capacity of the refrigeration cycle having a low evaporation temperature so that the total operating capacity matches, the chilled water outlet temperature can be stabilized at the target value even when the evaporation temperature exceeds a predetermined value. it can.

  In addition, when the pump of the heat source side heat medium circuit is variable, or using means (not shown) such as providing a circuit that bypasses the inlet / outlet of the heat source side heat medium circuit via a flow rate adjustment valve, By adopting a configuration in which the flow rate passing through the exchanger can be adjusted, when the heat source side water heat exchanger 4 is condensed and the condensation temperature becomes a predetermined value or less, or the heat source side water heat exchanger 4 is used by evaporation. When the evaporation temperature sometimes exceeds a predetermined value, reducing the flow rate that passes through the heat source side water heat exchanger increases the outflow temperature of each heat source side water heat exchanger, thus increasing the condensation temperature. Can do.

  Further, when the load-side heat medium circuit pump is variable, or using means (not shown) such as providing a circuit for bypassing the inlet / outlet of the load-side heat medium circuit via a flow rate adjustment valve, By adopting a configuration in which the flow rate passing through the exchanger can be adjusted, when the load-side water heat exchanger 6 is used for condensation, the condensation temperature becomes a predetermined value or less, or the load-side water heat exchanger 6 is used for evaporation. When the evaporation temperature sometimes exceeds a predetermined value, reducing the flow rate that passes through the load-side water heat exchanger reduces the outflow temperature of each load-side water heat exchanger, thus reducing the evaporation temperature. Can do.

  In addition, in the conventional constant speed machine, when the power source frequency is 50 Hz and 60 Hz, the capability is small at 50 Hz but the COP is high. In a refrigerating and air-conditioning apparatus whose operating capacity is variable by an inverter such as the heat source apparatus 1, the maximum value of the operating capacity of the compressor is changed according to the supplied power frequency, so that the equipment designer can change from the conventional constant speed machine. Can be easily replaced.

  In addition, this Embodiment is not limited to the structure from two refrigeration cycles, A heat-source side and load side heat-medium circuit are each connected in series using the refrigeration cycle more than that as shown in FIG. You may do it.

  As shown in FIG. 12, by increasing the number of connected refrigeration cycles, the average condensation temperature decreases and the average evaporation temperature increases, so that the COP is further improved and highly efficient operation is possible.

  In addition, although R410A was mentioned as an example and demonstrated as a refrigerant | coolant, the same effect is acquired even if it is another refrigerant | coolant, for example, R407C, R404A, NH3, CO2.

Embodiment 2. FIG.
FIG. 13 is a refrigerant circuit diagram of a refrigerating and air-conditioning apparatus according to Embodiment 2 of the present invention. In the figure, the same parts as those in Embodiment 1 are denoted by the same reference numerals. In the refrigeration cycle 2 of the present embodiment, heat exchange is performed between the refrigerant flowing out of the heat source side water heat exchanger 4 that is a condenser and the refrigerant flowing out of the load side water heat exchanger 6 that is an evaporator. The internal heat exchanger 7 is provided. As the internal heat exchanger 7, for example, a double tube type is used. In addition, refrigerant temperature detectors 22g and 22h for detecting the temperature of the refrigerant flowing out of the internal heat exchanger 7 and flowing into the expansion valve 5 are provided. Other configurations and compressor operating capacity control are the same as those in the first embodiment, and are therefore omitted.

  FIG. 14 is a Mollier diagram showing the operation of the refrigeration cycle 2 of the present embodiment using the internal heat exchanger 7. Since the operation of the refrigeration cycle is the same as that of the refrigeration cycles 2a and 2b, the refrigeration cycle 2a will be described as a representative. The high-temperature and high-pressure gas refrigerant (A1) discharged from the compressor 3a flows into the heat source side water heat exchanger 4a, and is condensed and liquefied by releasing heat to the cooling water that is the heat source side heat medium (B1). The temperature of the liquefied high-pressure liquid refrigerant is further lowered by exchanging heat with the low-pressure gas refrigerant in the internal heat exchanger 7a (B1a). The liquid refrigerant that has flowed out of the internal heat exchanger 7a is decompressed by the expansion valve 5a to become a low-pressure two-phase refrigerant, and flows into the load-side water heat exchanger 6a (C1). The load-side water heat exchanger 6a evaporates and gasifies by absorbing heat from the cold water that is the load-side heat medium (D1a), cools the water, and generates cold water. The low-pressure gas refrigerant that has flowed out of the load-side water heat exchanger 6a is heated by the internal heat exchanger 7a and sucked into the compressor 3a (D1).

  FIG. 15 shows the relationship between evaporator superheat and COP. The abscissa indicates the outlet superheat degree of the load-side water heat exchanger 6 used as an evaporator, and the ordinate indicates the COP ratio based on the COP when the outlet superheat degree is 3 ° C. It can be seen that the COP decreases as the evaporator outlet superheat increases. That is, the load-side water heat exchanger 6 is operated more efficiently when it is used in a state where the degree of superheat is as low as possible.

  In the refrigeration cycle, if the refrigerant sucked into the compressor 3 becomes two-phase and enters a liquid back state, problems such as shaft seizure due to a decrease in the lubricating oil concentration in the compressor 3 and overcurrent due to liquid compression are likely to occur. Therefore, in the refrigeration cycle 2 that does not include the internal heat exchanger 7 as in the first embodiment, the load-side water heat exchanger 6 that is employed as an evaporator flows out in order to suppress liquid back to the compressor 3. By making the refrigerant to be heated into a superheated gas state, liquid back to the compressor 3 is suppressed.

  When the load-side water heat exchanger 6 is a plate heat exchanger, refrigeration oil is likely to accumulate when an overheated gas region is generated in the plate heat exchanger. Since the superheated gas region is eliminated by making the outlet into saturated gas, the refrigerating machine oil can be prevented from staying, and the compressor 3 can be prevented from being exhausted.

  In the present embodiment, the internal heat exchanger 7 is provided and heat exchange is performed between the refrigerant flowing out of the heat source side water heat exchanger acting as a condenser and the refrigerant flowing out of the load side water heat exchanger acting as an evaporator. Thus, the refrigerant flowing out of the load-side water heat exchanger can be superheated and gasified using the refrigerant flowing out of the heat source-side water heat exchanger as a heat source. That is, since the refrigerant sucked into the compressor 3 can be brought into the superheated gas state while efficiently using the load-side water heat exchanger, the reliability of the heat source device 1 is improved while performing a highly efficient operation. To do.

  The internal heat exchanger 7 is not limited to a double tube type, and a plate heat exchanger may be used. Further, as shown in FIG. 16, the refrigerant pipe on the outlet side of the load-side water heat exchanger, that is, the internal heat exchanger low-pressure side pipe 61, the refrigerant pipe on the heat-source-side water heat exchanger outlet side, that is, the internal heat exchanger high-pressure side pipe 62. You may use what wound up.

  The heat exchange amount of the internal heat exchanger 7 is determined by the temperature difference between the heat source side water heat exchanger outlet and the load side water heat exchanger outlet temperature. If the temperature difference is large, the heat exchange amount increases. If the temperature difference is small, the heat exchange amount is The amount decreases. When the suction superheat degree of the compressor 3 is controlled to be constant, the evaporator outlet may be two-phase depending on the operation state, and the heat exchanger may not be used effectively. Therefore, in the second embodiment, the refrigerant temperature detectors 22e and 22g may be provided at the high-pressure side inlet / outlet of the internal heat exchanger 7, and the load-side water heat exchanger outlet may be controlled to be a saturated gas.

  Specifically, with respect to the refrigeration cycle 2a, first, the internal heat exchanger 7e is determined from the refrigerant temperature at the high-pressure side inlet / outlet of the internal heat exchanger detected by the refrigerant temperature detectors 22e and 22g and the pressure detected by the pressure detector 23a on the high-pressure side. The high pressure side inlet enthalpy H1 and the high pressure side outlet enthalpy H2 are estimated. Here, if the internal heat exchanger low-pressure side inlet enthalpy is H3 and the internal heat exchanger low-pressure side outlet enthalpy is H4, the flow rate of refrigerant passing through the internal heat exchanger 7 is equal in each refrigeration cycle 2, so H1-H2 = H4-H3 holds. Here, since it is desired to control H3 to be a saturated gas, H3 is a saturated gas enthalpy determined by the pressure detected by the pressure detector 23b. Further, since H1 and H2 are estimated, H4 is determined. Therefore, the target temperature of the refrigerant temperature detector 22b from the pressure detectors 23b and H4, that is, the low pressure side outlet superheat degree of the internal heat exchanger 7 is determined. .

  In this way, by changing the target suction superheat degree according to the operating state, the evaporator outlet can always be in a saturated gas state, and the heat exchanger can be effectively used. Therefore, the heat source unit 1 can be operated efficiently. Become.

  In addition, the refrigerant temperature detector was previously provided at the outlet of the internal heat exchanger and the enthalpy was estimated, but the outlet of the heat source side water heat exchanger was provided with a refrigerant container having a volume such that the inside of the container was always in a two-phase state. Thus, the saturated heat enthalpy may always be used for the internal heat exchanger high-pressure side inlet.

Embodiment 3 FIG.
FIG. 17 is a refrigerant circuit diagram of a refrigerating and air-conditioning apparatus according to Embodiment 3 of the present invention. In the drawing, the same parts as those of Embodiment 2 are given the same reference numerals. In the refrigeration air conditioner of the present embodiment, the refrigeration cycle 2 includes a four-way valve 8a (8b) and check valves 9a, 9b, 9c, 9d (9e, 9) so that cold water and hot water can be generated by the load-side water heat exchanger 6. 9f, 9g, 9h) and four-way valves 8c, 8d in the heat source side heat medium circuit and the load side heat medium circuit, respectively, and the heat source side water heat exchanger 4 and the load side water heat exchanger regardless of the operation mode. 6 is different from the above-described second embodiment in that the refrigerant and the heat medium flow are opposed to each other in the sixth embodiment, and other configurations are the same as those in the second embodiment.

  According to the present embodiment, the flow of the refrigerant and water flows when the four-way valve 8 is switched to the solid line side when making cold water in the load-side water heat exchanger 6 and when the four-way valve 8 makes hot water. Each flow is switched to the dotted line side. Since the refrigeration cycles 2a and 2b are the same, the refrigeration cycle 2a will be described as a representative. First, when making cold water with the load side water heat exchanger 6, the high-temperature and high-pressure gas refrigerant discharged from the compressor 3a flows into the heat source side water heat exchanger 4a after passing through the four-way valve 8a in the direction of the solid line, It is condensed and liquefied by dissipating heat to the cooling water that is the heat source side heat medium. The liquefied high-pressure liquid refrigerant passes through the check valve 9a and flows into the internal heat exchanger 7a, and the temperature is further lowered by exchanging heat with the low-pressure gas refrigerant. The liquid refrigerant that has flowed out of the internal heat exchanger 7a is decompressed by the expansion valve 5a to become a low-pressure two-phase refrigerant, and flows into the load-side water heat exchanger 6a after passing through the check valve 9d. The load-side water heat exchanger 6a evaporates and gasifies by absorbing heat from the cold water that is the load-side heat medium, cools the water, and generates cold water. The low-pressure gas refrigerant that has flowed out of the load-side water heat exchanger 6a passes through the four-way valve 8a in the direction of the solid line, is heated by the internal heat exchanger 7a, and is sucked into the compressor 3a.

  Next, operation | movement of the refrigerating cycle in the case of making warm water with the load side water heat exchanger 6 is demonstrated. The high-temperature and high-pressure gas refrigerant discharged from the compressor 3a passes through the four-way valve 8a in the dotted line direction, then flows into the load-side water heat exchanger 6a, and is condensed and liquefied by releasing heat to the load-side heat medium water. Then, the water is heated to produce warm water. The liquefied high-pressure liquid refrigerant passes through the check valve 9b and flows into the internal heat exchanger 7a, and the temperature is further lowered by exchanging heat with the low-pressure gas refrigerant. The liquid refrigerant that has flowed out of the internal heat exchanger 7a is decompressed by the expansion valve 5a to become a low-pressure two-phase refrigerant, and flows into the heat source side water heat exchanger 4a after passing through the check valve 9c. The heat source side water heat exchanger 4a evaporates and gasifies by absorbing heat from the heat source side heat medium. The low-pressure gas refrigerant that has flowed out of the heat source side water heat exchanger 4a passes through the four-way valve 8a in the direction of the dotted line, and is then heated by the internal heat exchanger 7a and sucked into the compressor 3a.

  Next, the operation of the heat source side heat medium circuit and the load side heat medium circuit during cold water generation will be described. When cold water is generated by the load-side water heat exchanger 6, the respective heat media pass through the solid line portions of the four-way valves 8c and 8d, respectively. Moreover, when producing | generating warm water with the load side water heat exchanger 6, each heat medium each passes the dotted-line part of the four-way valves 8c and 8d, respectively. First, the operation at the time of cold water generation will be described. At the time of cold water generation, the water conveyed by the water pump 31a passes through the four-way valve 8c in the direction of the solid line and then flows into the refrigeration cycle 2a, that is, the load-side water heat exchanger 6a. The cold water cooled by the load side water heat exchanger 6a is then further cooled by the refrigeration cycle 2b, that is, the load side water heat exchanger 6b. The water that has flowed out of the load-side water heat exchanger 6b again passes through the four-way valve 8c in the direction of the solid line and flows to the load-side device. In the heat source side heat medium circuit, the water conveyed by the water pump 31b passes through the four-way valve 8d in the direction of the solid line and then flows into the refrigeration cycle 2b, that is, the heat source side water heat exchanger 4b. The water whose temperature has been raised in the heat source side water heat exchanger 4b is further raised in temperature in the refrigeration cycle 2a, that is, the heat source side water heat exchanger 4a. The water that has flowed out of the heat source side water heat exchanger 4a again passes through the four-way valve 8d in the direction of the solid line and flows to the heat source side device.

  Next, the operation of the heat source side heat medium circuit and the load side heat medium circuit during hot water generation will be described. The water conveyed by the water pump 31a passes through the four-way valve 8c in the direction of the dotted line, and then flows into the refrigeration cycle 2b, that is, the load-side water heat exchanger 6b. The hot water heated by the load side water heat exchanger 6b is then further heated by the refrigeration cycle 2a, that is, the load side water heat exchanger 6a. The water that has flowed out of the load-side water heat exchanger 6a again passes through the four-way valve 8c in the dotted line direction and flows to the load-side device. In the heat source side heat medium circuit, the water conveyed by the water pump 31b passes through the four-way valve 8d in the dotted line direction, and then flows into the refrigeration cycle 2a, that is, the heat source side water heat exchanger 4a. The water cooled by the heat source side water heat exchanger 4a is then further cooled by the refrigeration cycle 2b, that is, the heat source side water heat exchanger 4b. The water that has flowed out of the heat source side water heat exchanger 4b again passes through the four-way valve 8d in the dotted line direction and flows to the heat source side device.

  In this embodiment, since the refrigeration cycle 2, the heat source side heat medium circuit, and the load side heat medium circuit are each provided with the four-way valve 8, cold / warm water can be generated by the load side water heat exchanger 6, and therefore, to the load side device. The temperature range of the water to be conveyed can be expanded, and a highly convenient operation can be realized.

  As an example of use of the present invention, the present invention is particularly useful for a refrigerating and air-conditioning apparatus that uses liquid media such as water and brine on the heat source side and load side, and supplies cold and hot heat to the load side by heating and cooling the heat medium.

  1 heat source machine, 2a, 2b, 2x, 2y refrigeration cycle, 3a, 3b, 3x, 3y compressor, 4a, 4b, 4x, 4y heat source side water heat exchanger, 5a, 5b, 5x, 5y expansion valve, 6a, 6b, 6x, 6y Load side water heat exchanger, 7a, 7b Internal heat exchanger, 8a-8d Four-way valve, 9a-9h Check valve, 21a-21p Heat medium temperature detector, 22a-22h Refrigerant temperature detector, 23a-23d, 23w-23z Pressure detector, 31a, 31b Water pump, 41 Control device, 51a Load side heat medium circuit, 51b Heat source side heat medium circuit, 61 Internal heat exchanger low pressure side piping, 62 Internal heat exchanger high pressure Side piping.

Claims (14)

Provided with a plurality of refrigeration cycles configured by annularly connecting a compressor having a variable operating capacity, a heat source side heat exchanger, a pressure reducing device, and a load side heat exchanger,
In the heat source side heat exchanger of each refrigeration cycle, the heat source side heat medium radiates or absorbs heat, and the flow path of the heat source side heat medium is configured to flow in series through the heat source side heat exchanger of each refrigeration cycle,
In the load-side heat exchanger of each refrigeration cycle, the load-side heat medium is cooled or heated to supply cold / hot heat, and the flow path of the load-side heat medium flows through the load-side heat exchanger of each refrigeration cycle in series. Configured,
The load-side heat medium inflow temperature of the load-side heat exchanger of the refrigeration cycle positioned upstream with respect to the flow path of the load-side heat medium and the load of the refrigeration cycle positioned downstream with respect to the flow path of the load-side heat medium A heat medium temperature detecting means for detecting the load side heat medium outflow temperature of the side heat exchanger;
The total value of the compressor operating capacity of each refrigeration cycle is controlled so that the temperature difference between the load-side heat medium inflow temperature and the load-side heat medium outflow temperature detected by the heat medium temperature detection means becomes a predetermined value. A control device;
A refrigerating and air-conditioning apparatus comprising:   The control device controls the compressor operating capacity by determining the compressor operating capacity ratio of each refrigeration cycle so as to be proportional to the compressor rated capacity of each refrigeration cycle or the rated capacity of the load-side heat exchanger. The refrigerating and air-conditioning apparatus according to claim 1. The load side heat exchanger of each refrigeration cycle is provided with a heat medium temperature detecting means for detecting the inflow temperature and the outflow temperature of the load side heat medium
The controller determines that the temperature difference between the inflow temperature and the outflow temperature of the load-side heat exchanger detected by the temperature detection means of each refrigeration cycle is proportional to the compressor rated capacity of each refrigeration cycle or the rated capacity of the load-side heat exchanger. The refrigerating and air-conditioning apparatus according to claim 1, wherein the compressor operating capacity is controlled to do so. Refrigerant temperature detection means for detecting the condensation temperature and evaporation temperature of each refrigeration cycle,
The control device estimates the compressor efficiency from the condensation temperature and evaporation temperature detected by the refrigerant temperature detecting means of each refrigeration cycle and the compressor operating capacity so that the average value of the compressor efficiency of each refrigeration cycle is maximized. The refrigeration air conditioner according to any one of claims 1 to 3, wherein the compressor operating capacity is controlled.   5. The internal heat exchanger for exchanging heat between the refrigerant flowing out of the heat source side heat exchanger and the refrigerant flowing out of the load side heat exchanger is provided in each refrigeration cycle. A refrigeration air conditioner according to claim 1. Refrigerant temperature detection means for detecting the inflow temperature and the outflow temperature of the high-pressure side refrigerant of the internal heat exchanger of each refrigeration cycle, and the outflow temperature of the low-pressure side refrigerant of the internal heat exchanger,
The refrigerating and air-conditioning apparatus according to claim 5, wherein the control means controls the decompression device so that the low-pressure side inlet of the internal heat exchanger becomes saturated gas.   The heat source side heat exchanger of the refrigeration cycle located on the most upstream side with respect to the flow path of the load side heat medium is configured to be the most downstream with respect to the flow path of the heat source side heat medium. The refrigerating and air-conditioning apparatus according to any one of claims 1 to 6. A refrigeration cycle configured by annularly connecting a compressor having a variable operating capacity, a refrigerant flow path switching valve for switching a refrigerant flow path, a heat source side heat exchanger, a pressure reducing device, and a load side heat exchanger. A heat source side heat medium flow switching valve for switching the heat medium flow path of the heat source side heat medium circuit connected to the heat source side heat exchanger of each refrigeration cycle, and a load side heat exchanger of each refrigeration cycle A load-side heat medium flow switching valve for switching the heat medium flow path of the connected load-side heat medium circuit;
In the heat source side heat exchanger of each refrigeration cycle, the heat source side heat medium radiates or absorbs heat, and the flow path of the heat source side heat medium is configured to flow in series through the heat source side heat exchanger of each refrigeration cycle,
Further, the load-side heat medium is cooled or heated in the load-side heat exchanger of each refrigeration cycle to supply cold / hot heat, and the flow path of the load-side heat medium flows in series through the load-side heat exchanger of each refrigeration cycle. Configured as
A refrigerant flow path switching valve for each refrigeration cycle so that the refrigerant passing through the heat source side heat exchanger and the load side heat exchanger and each heat medium always flow countercurrently regardless of the operation mode. A refrigeration air conditioner comprising a control device for controlling a heat source side heat medium flow switching valve and a load side heat medium flow switching valve.   The refrigerating and air-conditioning apparatus according to any one of claims 1 to 8, wherein the refrigerating and air-conditioning apparatus includes three or more refrigerating cycles. Refrigerant temperature detection means for detecting the condensation temperature of each refrigeration cycle,
When the condensing temperature of each refrigeration cycle exceeds a predetermined value, the control device reduces the compressor operating capacity of the refrigeration cycle where the condensing temperature exceeds the predetermined value, and compresses the refrigeration cycle whose condensing temperature is lower than the predetermined value. 9. The refrigerating and air-conditioning apparatus according to claim 1, wherein the compressor operating capacity of each refrigeration cycle is controlled so as to increase the machine operating capacity. Refrigerant temperature detection means for detecting the evaporation temperature of each refrigeration cycle,
When the evaporation temperature of each refrigeration cycle is equal to or higher than a predetermined value, the control device increases the compressor capacity of the refrigeration cycle where the evaporation temperature is equal to or higher than the predetermined value, and the compressor of the refrigeration cycle whose evaporation temperature is equal to or lower than the predetermined value. 9. The refrigeration air conditioner according to claim 1, wherein the compressor capacity of each refrigeration cycle is controlled so as to reduce the capacity. Refrigerant temperature detection means for detecting the condensation temperature and evaporation temperature of each refrigeration cycle, and a heat source side heat medium flow adjustment device for adjusting the flow rate of the heat source side heat medium in the flow path of the heat source side heat medium,
When the condensation temperature becomes a predetermined value or less when the heat source side heat exchanger is used for condensation, or when the evaporation temperature becomes a predetermined value or more when the heat source side heat exchanger is used for evaporation, the control device The refrigerating and air-conditioning apparatus according to claim 1 or 8, wherein the flow rate adjusting device is controlled so that the flow rate decreases. Refrigerant temperature detection means for detecting the condensation temperature and evaporation temperature of each refrigeration cycle, and a load-side heat medium flow adjustment device for adjusting the flow rate of the load-side heat medium in the flow path of the load-side heat medium,
When the condensation temperature becomes a predetermined value or less when the load side heat exchanger is used for condensation, or when the evaporation temperature becomes a predetermined value or more when the load side heat exchanger is used for evaporation, the control device The refrigerating and air-conditioning apparatus according to claim 1 or 8, wherein the flow rate adjusting device is controlled so as to reduce a flow rate.   The refrigerating and air-conditioning apparatus according to any one of claims 1 to 13, wherein a maximum value of a compressor operating capacity of each refrigeration cycle is changed according to a power supply frequency supplied to the control device.

Images