Refrigeration cycle system

Abstract

The refrigeration cycle system comprises: a refrigerant circuit which has a compressor and through which a refrigerant is circulated by the compressor; a heat medium circuit which has a heat source si

Description

Technical Field

[0001] The present disclosure relates to a refrigeration cycle system configured to supply a heat medium, such as water having exchanged heat with refrigerant, to a load device. Background Art

[0002] A refrigeration cycle system is known that includes a refrigeration cycle apparatus being a heat source apparatus including a refrigerant circuit in which refrigerant circulates. The refrigeration cycle system is configured to cause a heat medium (for example, water) of a heat medium circuit to exchange heat with refrigerant in the refrigeration cycle apparatus and supply the heat medium after heat exchange to a load device (for example, an air-conditioning apparatus). In a refrigeration cycle system, a heat exchanger in which refrigerant is caused to exchange heat with a heat medium (hereafter, also referred to as a water heat exchanger) experiences a reduction of heat exchange efficiency due to scales depositing with time in a flow passage of the heat medium and generated from calcium or other chemical component contained in the heat medium. When equal to or greater than a certain amount of accretion such as scales deposit on the water heat exchanger, heat exchange between the refrigerant and the heat medium may be extremely inhibited, leading to an abnormal condition. Thus, there is a known refrigeration cycle system that can diagnose the scale depositing status of the accretion. The system prevents clogging of the water heat exchanger, in other words, abnormal condition, from occurring by an operator of a periodical checkup executing cleaning depending on the result of diagnosis (see, for example, Patent Literature 1). The refrigeration cycle system of Patent Literature 1 diagnoses scale depositing status of accretion based on the heat exchange efficiency between the refrigerant and the heat medium. Specifically, the refrigeration cycle system of Patent Literature 1 is configured to calculate a temperature difference between a saturation temperature of the refrigerant and a temperature of the heat medium flowing out of the water heat exchanger, to diagnose the scale depositing status of accretion in the water heat exchanger by using the temperature difference. Citation List Patent Literature

[0003] Patent Literature 1: WO2021 / 250789 Summary of Invention Technical Problem

[0004] However, in general, the saturation temperature of the refrigerant may easily change due to fluctuation of the load and changes in operating conditions because the refrigerants experience repeating refrigeration cycles accompanied by changes of states, pressure changes, and temperature changes during circulation through the refrigerant circuit. Therefore, there have been a challenge in the accuracy of determination in such a configuration as disclosed in Patent Literature 1 in which the scale depositing status of accretion of the water heat exchanger is determined by using the temperature difference between the saturation temperature of the refrigerant and the temperature of the heat medium flowing out of the water heat exchanger, because it is affected by the fluctuation of load and changes in operating conditions.

[0005] The refrigeration cycle system of the present disclosure is made in view of the above problems. Its objective is to provide a refrigeration cycle system that can more accurately determine the scale depositing status of accretion in a flow passage of the heat medium in a water heat exchanger (heat exchanger) than related techniques. Solution to Problem

[0006] The first refrigeration cycle system according to an embodiment of the present disclosure is a refrigeration cycle system including a refrigerant circuit, the refrigerant circuit including a compressor, the compressor being configured to circulate refrigerant in the refrigerant circuit, a heat medium circuit including a heat source-side pump, the heat source-side pump being configured to circulate a heat medium in the heat medium circuit, a heat exchanger configured to cause the refrigerant and the heat medium to exchange heat with each other, and a system controller configured to control the heat source-side pump, the heat medium circuit including a load device provided downstream of the heat exchanger and a bypass pipe bypassing the load device, the refrigeration cycle system comprising: a first detecting unit provided at the heat medium circuit, and configured to detect a pressure difference between forwardly and backwardly adjacent positions of the heat exchanger in the heat medium circuit; and a second detecting unit provided at the heat medium circuit, and configured to detect a bypass pressure difference between the forwardly and backwardly adjacent positions of the bypass pipe in the heat medium circuit, wherein the system controller is configured to obtain pump head of the heat source-side pump from the pressure difference detected by the first detecting unit and a rotation speed of the heat source-side pump, to calculate the bypass pressure difference between the forwardly and backwardly adjacent positions of the bypass pipe in the heat medium circuit based on the pressure difference and the pump head, and compare a difference between the calculated value of the bypass pressure difference and a measured value of the bypass pressure difference detected by the second detecting unit with a difference value stored in advance to determine a depositing status of scales on the heat exchanger.

[0007] The second refrigeration cycle system according to another embodiment of the present disclosure is a refrigeration cycle system including a refrigerant circuit, the refrigerant circuit including a compressor, the compressor being configured to circulate refrigerant in the refrigerant circuit, a heat medium circuit including a heat source-side pump, the heat source-side pump being configured to circulate a heat medium in the heat medium circuit, a heat exchanger configured to cause the refrigerant and the heat medium to exchange heat with each other, and a system controller configured to control the heat source-side pump, the heat medium circuit including a load device provided downstream of the heat exchanger and a bypass pipe bypassing the load device, the refrigeration cycle system comprising: a first detecting unit provided at the heat medium circuit, and configured to detect a pressure difference between forwardly and backwardly adjacent positions of the heat exchanger in the heat medium circuit; and a second detecting unit provided at the heat medium circuit, and configured to detect a pump pressure difference between forwardly and backwardly adjacent positions of the heat source-side pump in the heat medium circuit, wherein the system controller is configured to obtain pump head of the heat source-side pump from the pressure difference detected by the first detecting unit and a rotation speed of the heat sourceside pump, to calculate a bypass pressure difference between the forwardly and backwardly adjacent positions of the bypass pipe in the heat medium circuit based on the pressure difference and the pump head to obtain a first calculated value, calculate the bypass pressure difference between the forwardly and backwardly adjacent positions of the bypass pipe in the heat medium circuit based on the pressure difference detected by the first detecting unit and the pump pressure difference detected by the second detecting unit to obtain a second calculated value, and compare the difference between the first calculated value and the second calculated value of the bypass pressure difference with a difference value stored in advance to determine a depositing status of scales on the heat exchanger.

[0008] The third refrigeration cycle system according to another embodiment of the present disclosure is a refrigeration cycle system including a refrigerant circuit, the refrigerant circuit including a compressor, the compressor being configured to circulate refrigerant in the refrigerant circuit, a heat medium circuit including a heat source-side pump and a load-side pump, the heat source-side pump and the load-side pump being configured to circulate the heat medium in the heat medium circuit, a heat exchanger configured to cause the refrigerant and the heat medium to exchange heat with each other, and a system controller configured to control the heat source-side pump, the heat medium circuit including a load device provided downstream of the heat exchanger, and a free bypass pipe bypassing the load device, the heat source-side pump is configured to pump the heat medium to the heat exchanger, the load-side pump being configured to pump the heat medium to the load device, the refrigeration cycle system comprising: a first detecting unit provided at the heat medium circuit, and configured to detect a pressure difference between forwardly and backwardly adjacent positions of the heat exchanger in the heat medium circuit; and a second detecting unit provided at a loadside of the heat medium circuit and configured to detect a load-side flow rate of the heat medium, wherein the system controller is configured to obtain pump head of the heat source-side pump from the pressure difference detected by the first detecting unit and a rotation speed of the heat source-side pump, calculate the load-side flow rate of the heat medium flowing on the load-side of the heat medium circuit based on the pressure difference and the pump head, and compare a difference between the calculated value of the load-side flow rate, and a measured value of the load-side flow rate detected by the second detecting unit with a difference value stored in advance to determine a depositing status of scales on the heat exchanger.

[0009] A fourth refrigeration cycle system according to another embodiment of the present disclosure is a refrigeration cycle system including a refrigerant circuit, the refrigerant circuit including a compressor, the compressor being configured to circulate refrigerant in the refrigerant circuit, a heat medium circuit including a heat source-side pump and a load-side pump, the heat source-side pump and the load-side pump being configured to circulate a heat medium in the heat medium circuit, a heat exchanger being configured to cause the refrigerant and the heat medium to exchange heat with each other, and a system controller configured to control the heat source-side pump, the heat medium circuit including a load device provided downstream of the heat exchanger, and a free bypass pipe bypassing the load device, the heat source-side pump being configured to pump the heat medium to the heat exchanger, the load-side pump being configured to pump the heat medium to the load device, the refrigeration cycle system comprising: a first detecting unit provided at the heat medium circuit, and configured to detect a pressure difference between forwardly and backwardly adjacent positions of the heat exchanger in the heat medium circuit, and a second detecting unit provided at the heat medium circuit and configured to detect a pump pressure difference between forwardly and backwardly adjacent positions of the heat source-side pump in the heat medium circuit, wherein the system controller is configured to obtain pump head of the heat source-side pump from the pressure difference detected by the first detecting unit and a rotation speed of the heat source-side pump, calculate a loadside flow rate of the heat medium flowing in a load-side of the heat medium circuit based on the pressure difference and the pump head to obtain a first calculated value, calculate the load-side flow rate of the heat medium flowing in a load-side of the heat medium circuit based on the pressure difference detected by the first detecting unit and the pump pressure difference detected by the second detecting unit to obtain the second calculated value, compare a difference between the first calculated value and the second calculated value of the load-side flow rate with a difference value stored in advance to determine a depositing status of scales on the heat exchanger. Advantageous Effects of Invention

[0010] In the first refrigeration cycle system, the second refrigeration cycle system, the third refrigeration cycle system and the fourth refrigeration cycle system of the embodiments of the present disclosure, a depositing status of scales of the heat exchanger is determined by comparing a difference between the calculated value and the measured value of the bypass pressure difference (or load-side flow rate) obtained through different methods by using the first detecting unit and the second detecting unit provided at the heat medium circuit, or a difference between the first calculated value and the second calculated value of the bypass pressure difference (or load-side flow rate), with a difference value stored in advance. In the present disclosure, since both the first detecting unit and the second detecting unit are provided at the heat medium circuit in which scale deposits, by determining the depositing status of scales on the heat exchanger based on their detection values, more accurate determination of the depositing status of scales can be executed in which fluctuation of load and change in operating conditions less affect the determination accuracy, as compared to conventional configurations in which the depositing status of scales of the heat exchanger is determined based on the temperature difference between the saturation temperature of the refrigerant and the temperature of the heat medium flowing out of the heat exchanger. Brief Description of Drawings

[0011] [Fig. 1] Fig. 1 is a circuitry diagram showing a general schematic configuration of a refrigeration cycle system of Embodiment 1 of the present disclosure. [Fig. 2] Fig. 2 is a circuitry diagram showing an exemplary configuration of refrigeration cycle apparatus of Fig. 1. [Fig. 3] Fig. 3 shows a relation of the flow rate and the head loss of a water heat exchanger of Fig. 1. [Fig. 4] Fig. 4 shows a pump head characteristic of a pump of Fig. 1. [Fig. 5] Fig. 5 is a flowchart of scale depositing determination executed by a system controller of Fig. 1. [Fig. 6] Fig. 6 is a circuitry diagram showing modification of the refrigeration cycle apparatus of Fig 2. [Fig. 7] Fig. 7 is a circuitry diagram showing a general schematic configuration of the refrigeration cycle system of Embodiment 2 of the present disclosure. [Fig. 8] Fig. 8 is a flowchart of scale depositing determination executed by the system controller of Fig. 7. Description of Embodiments

[0012] Hereafter, embodiments of the refrigeration cycle system of the present disclosure are described with reference to the drawings. The present disclosure is not limited to the embodiments below, but it can be modified in various ways within the scope of the present disclosure. Further, the refrigeration cycle system shown in the drawing is an example of the refrigeration cycle system of the present disclosure, and the refrigeration cycle system shown in the drawing does not limit the refrigeration cycle system of the present disclosure. Further, the same signs indicate the same or equivalent referents, which applies commonly throughout the entire specification.

[0013] Embodiment 1. (Configuration of refrigeration cycle system 10) Fig. 1 is a circuitry diagram showing a general schematic configuration of a refrigeration cycle system 10 of Embodiment 1 of the present disclosure. Fig. 2 is a circuitry diagram showing an exemplary configuration of the refrigeration cycle apparatus 20 of Fig. 1. In Fig. 2, void arrows with solid edges each indicate the direction in which the refrigerant flows, while the void arrows with dashed edges of Fig. 1 and Fig. 2 each indicate the direction in which the heat medium flows. Referring to Fig. 1 and Fig. 2, a general schematic configuration of the refrigeration cycle system 10 will be described.

[0014] As shown in Fig. 1, the refrigeration cycle system 10 includes a refrigerant circuit 27 in which refrigerant circulates, a heat medium circuit 40 in which a heat medium, such as water, circulates, and a water heat exchanger configured to cause the refrigerant and the heat medium to exchange heat with each other (hereafter also referred to as a heat exchanger 26). Here, it is assumed that the heat medium flowing through the heat medium circuit 40 is water, but other fluids, such as a non-freeze solution, may be applicable. The heat medium circuit 40 includes a heat source-side pump 30 that pumps a heat medium to the heat exchanger 26, and is configured to supply the heat medium having exchanged heat with the refrigerant at the heat exchanger 26 to the load device 70. The load device 70 is, for example, an air-conditioning apparatus.

[0015] The refrigeration cycle system 10 of Fig. 1 includes a plurality of refrigeration cycle apparatuses 20 in each of which the refrigerant circuit 27 is included. Any number of refrigeration cycle apparatuses 20 may be included in the refrigeration cycle system 10. Thus, this is for example, one. The refrigeration cycle apparatus 20 is configured to serve as a heat source apparatus, for example, an air cooling type heat pump chiller. The refrigeration cycle apparatus 20 is configured to include a part of the heat medium circuit 40. The plurality of refrigeration cycle apparatuses 20 each include a heat source-side branch pipe 40a which is described later and provided with a water heat exchanger (heat exchanger 26) and a heat source-side pump 30. In the heat medium circuit 40, the plurality of heat source-side branch pipes 40a are connected in parallel with each other, and connected to a part of the circuit on the loadside. In other words, the refrigeration cycle system 10 is configured such that, a heat medium circulating in one heat medium circuit 40, and refrigerant circulating through a refrigerant circuit 27 of each of a plurality of refrigeration cycle apparatuses 20, are caused to exchange heat, and supply the heat generated at the plurality of refrigeration cycle apparatus 20 to the one or more load devices 70 via the heat medium. The configuration of the heat medium circuit 40 is described later.

[0016] As shown in Fig. 2, the refrigerant circuit 27 is formed such that a compressor 22, an air heat exchanger (heat exchanger 24), an expansion device 25, and the water heat exchanger (heat exchanger 26) are connected into a circuit via refrigerant pipes. The compressor 22 is configured to compress refrigerant and circulate it through the refrigerant circuit 27. The compressor 22 comprises, for example, an inverter compressor configured such that, the capacity, being a delivery rate of refrigerant per unit time, is controlled by altering operation frequency. The heat exchanger 24 comprises, for example, a fin-and-tube heat exchanger, and configured to cause air and refrigerant to exchange heat with each other. A fan 28 supplies outdoor air to the heat exchanger 24 and facilitate heat exchange by the heat exchanger 24. The volume of airflow blown to the heat exchanger 24 is controlled by controlling the rotation speed of the fan 28. The expansion device 25 comprises, for example, an electronic expansion valve, and is configured to regulate the pressure of the refrigerant entering the water heat exchanger (heat exchanger 26) by varying the opening degree thereof. The expansion device 25 decompresses high-pressure refrigerant flowing out of the heat exchanger 24. The heat exchanger 26 is configured to cause the heat medium circulating through the heat medium circuit 40 and the refrigerant flowing through the refrigerant circuit 27 to exchange heat with each other.

[0017] In the refrigerant circuit 27 of Fig. 2, the discharge side of the compressor 22 is connected to the air heat exchanger (heat exchanger 24); the heat exchanger 24 and the expansion device 25 are connected with each other; the expansion device 25 and the water heat exchanger (heat exchanger 26) are connected with each other; and the heat exchanger 26 is connected to the suction-side of the compressor 22. In this case, the heat exchanger 24 serves as a condenser, and the water heat exchanger (heat exchanger 26) serves as an evaporator. In the heat exchanger 26, the heat medium pumped by the heat source-side pump 30, is cooled by the refrigerant decompressed by the expansion device 25 of the refrigerant circuit 27. In the example of Fig. 2, the heat medium and the refrigerant flow in parallel with each other at the heat exchanger 26.

[0018] The configuration of the refrigerant circuit 27 is not limited to this configuration. For example, a configuration may be possible in which, by providing a flow switching device, such as a four-way valve, to the refrigerant discharge side of the compressor 22, a cooling operation in which the refrigerant flows through the compressor 22, the heat exchanger 24, the expansion device 25 and the heat exchanger 26 in order, and the heating operation in which the refrigerant flows through the compressor 22, the heat exchanger 26, the expansion device 25 and the heat exchanger 24 in order, are switched. Further, in the example of Fig. 2, the heat exchanger 24 serving as a condenser may be constituted by an air heat exchanger so that refrigeration cycle apparatus 20 is of air cooling type. However, the heat exchanger 24 may be constituted by a water heat exchanger configuration so that the refrigeration cycle apparatus 20 is of water cooling type.

[0019] Further, the refrigeration cycle apparatus 20 includes a controller 21 configured to control the refrigerant circuit 27 and the heat source-side pump 30. Specifically, the controller 21 controls the frequency of the compressor 22, the opening degree of the expansion device 25, the rotation speed of the fan 28, and the frequency (in other words, a rotation speed) of the heat source-side pump 30.

[0020] The controller 21 is constituted by hardware such as a circuit device that implements the function. Otherwise, the function of the controller 21 may be implemented by having a memory storing a program and a Central Processing Unit (CPU) executing the program.

[0021] The refrigeration cycle apparatus 20 includes a heat exchanger pressure difference detecting unit 31 configured to detect the pressure difference between the inlet side and the outlet side of the heat medium of the water heat exchanger, in other words, the pressure difference between the forwardly and backwardly adjacent positions of the heat exchanger 26 at the heat source-side branch pipe 40a (hereafter, heat exchanger pressure difference). The heat exchanger pressure difference detecting unit 31 comprises, for example, a differential pressure gauge. The controller 21 of the refrigeration cycle apparatus 20 is connected to the heat exchanger pressure difference detecting unit 31, and receives input of, a heat exchanger pressure difference △Phex(i) detected by the heat exchanger pressure difference detecting unit 31. Hereafter, the heat exchanger pressure difference detecting unit 31 may be referred to as a first detecting unit.

[0022] Instead of the differential pressure gauge constituting the heat exchanger pressure difference detecting unit 31, two pressure sensors may be installed at each of the forwardly and backwardly adjacent positions in the heat medium circuit of the heat exchanger 26, respectively, so that the controller 21 acquires the heat exchanger pressure difference APhex(i) therefrom in such a configuration.

[0023] Hereafter, referring to Fig. 1, the configuration of the heat medium circuit 40 will be described. In the example of Fig. 1, two load devices 70 are provided at a part of the circuit on the load-side of the heat medium circuit 40. Any number of load device(s) 70 may be provided at the part of the circuit on load-side of the refrigeration cycle system 10. For example, it may be one, or three or more. The load device 70 may be, for example, an air-conditioning apparatus such as an air handling unit or a fan coil unit. The load device 70 includes a load-side heat exchanger (not shown in the drawings) configured to cause indoor air and the heat medium circulating through the heat medium circuit 40 to exchange heat with each other.

[0024] As shown in Fig. 1, each of the part of the circuit on the load-side of the heat medium circuit 40 includes a plurality of load-side branch pipes 40b connected in parallel with each other, to which the load device 70 is connected, and a second return water-side header pipe 42b to which a downstream end part of each of the plurality of load-side branch pipes 40b is provided. A part of the circuit on the load-side of the heat medium circuit 40 includes a merger section pipe 40c connecting between the second return water-side header pipe 42b and a first return water-side header pipe 42a described later. To each of the load-side branch pipes 40b is provided a load-side expansion valve 71 being, for example, a proportion two-way valve. The load-side expansion valve 71 is provided between a side on which a heat medium flows out of the load device 70 in the load-side branch pipe 40b, in other words, between the load device 70 and the second return water-side header pipe 42b. Further, at the merger section pipe 40c, a load-side flow rate detector 73 configured to detect a flow rate of the heat medium flowing through the part of the circuit on the load-side of the heat medium circuit 40 (hereafter also referred to as a load-side flow rate) is provided. In the refrigeration cycle system 10 of Embodiment 1, the load-side flow rate detector 73 may be omitted.

[0025] As shown in Fig. 1, the heat source-side part of the circuit of the heat medium circuit 40, a first return water-side header pipe 42a connected to the second return water-side header pipe 42b via the merger section pipe 40c, a forward water-side header pipe 41 to which an upstream end part of each of the plurality of load-side branch pipes 40b is connected, a plurality of heat source-side branch pipes 40a to each of which the heat exchanger 26 and the heat source-side pump 30 are provided. The downstream end parts of the plurality of heat source-side branch pipes 40a is connected to the forward water-side header pipe 41, the upstream end parts of the plurality of heat source-side branch pipes 40a are connected to the first return waterside header pipe 42a.

[0026] The first return water-side header pipe 42a distributes a heat medium returning from the load-side part of the circuit to the plurality of heat source-side branch pipes 40a. Each heat source-side pump 30 pumps the heat medium divided at the first return water-side header pipe 42a to the water heat exchanger (heat exchanger 26). The heat medium pumped to the heat exchanger 26 by the heat source-side pump 30 is cooled by exchanging heat with the refrigerant of the refrigerant circuit 27 at the heat exchangers 26. The heat medium cooled at each of the plurality of heat exchanger 26, enters the forward water-side header pipe 41. The forward water-side header pipe 41 allows the flows of the heat medium cooled at the plurality of refrigeration cycle apparatuses 20 entering the forward water-side header pipe 41 to merge and be distributed and supplied to the plurality of load devices 70 provided in the downstream side.

[0027] Further, the heat medium circuit 40 includes, a bypass pipe 80 that bypasses the load-side part of the circuit (in other words, bypasses the plurality of load devices 70). The bypass pipe 80 connects the forward water-side header pipe 41 and the first return water-side header pipe 42a provided at forwardly and backwardly adjacent positions in the heat medium circuit of the plurality of refrigeration cycle apparatuses 20 in the heat medium circuit 40 with each other.

[0028] The refrigeration cycle system 10 of Embodiment 1 as shown in Fig. 1 adopts a single pump system in which the heat source-side pump 30 is provided only at the heat source-side part of the circuit in the heat medium circuit 40. That is, the pump is not provided at the load-side part of the circuit. At the bypass pipe 80 is provided a bypass valve 81 configured to adjust the flow rate of the heat medium flowing through the bypass pipe 80. A single pump system is configured such that a pressure difference between forwardly and backwardly adjacent positions in the heat medium circuit of the bypass pipe 80 (hereafter, also referred to as a bypass pressure difference), in other words, the pressure difference between the forward water-side header pipe 41 provided upstream of the bypass pipe 80 and the first return water-side header pipe 42a provided in downstream thereof is adjusted via the opening degree of the bypass valve 81. Further, the refrigeration cycle system 10 of Embodiment 1 includes a bypass pressure difference detecting unit 90 configured to detect a bypass pressure difference between the forwardly and backwardly adjacent positions in the heat medium circuit of the bypass pipe 80. The bypass pressure difference detecting unit 90 comprises, for example, a differential pressure gauge. Hereafter, the bypass pressure difference detecting unit 90 may be referred to as a second detecting unit.

[0029] The refrigeration cycle system 10 includes a system controller 21a configured to control the heat medium circuit 40. The system controller 21a comprises hardware, such as, a circuit device that implements the function. The system controller 21 a comprises a memory storing a program and a Central Processing Unit (CPU). The CPU executing the program implements the function of the system controller 21 a.

[0030] The system controller 21a is connected to each of the load-side flow rate detector 73, the bypass pressure difference detecting unit 90, and bypass valve 81. The system controller 21a receives each input of a load-side flow rate detected by the loadside flow rate detector 73, and a bypass pressure difference (measured value B of the bypass pressure difference) detected by the bypass pressure difference detecting unit 90. The system controller 21a outputs a designated opening degree to the bypass valve 81.

[0031] The input to the system controller 21a and the output from the system controller 21a as described above are input or output as, for example, an electrical current signal of DC4-20[mA], In this case, an electrical current of each electrical current signal is an electrical current according to the load-side flow rate, the bypass pressure difference, or opening degree designated to the bypass valve 81.

[0032] Instead of using the bypass pressure difference detecting unit 90 as a differential pressure gauge, two pressure sensors may be used, installed at forwardly and backwardly adjacent positions in the heat medium circuit of the bypass pipe 80, in other words, at the forward water-side header pipe 41 and the first return water-side header pipe 42a so that the system controller 21a is configured to obtain a bypass pressure difference.

[0033] In the refrigeration cycle system 10, the controller 21 of the refrigeration cycle apparatus 20, is configured to controls in cooperation with a controller 21 of other refrigeration cycle apparatuses 20, operation of the refrigerant circuit 27 and the heat source-side pump 30 that correspond to the controller 21. For cooperation, one of the plurality of refrigeration cycle apparatuses 20 may be preset as a proxy apparatus, and the controller 21 of the proxy apparatus may execute communications with the controller 21 of each refrigeration cycle apparatus 20 other than the proxy apparatus. In the example of Fig. 1, the controller 21 of the proxy apparatus (refrigeration cycle apparatus 20 shown in the lower part of the drawing) serves as the system controller 21a.

[0034] The system controller 21a acquire an operation frequency Fp(i) of the heat source-side pump 30 and the pressure difference between pressures at forwardly and backwardly adjacent positions respectively of the heat exchanger 26 in the heat medium circuit (heat exchanger pressure difference APhex(i)) from each refrigeration cycle apparatus 20. Further, as described above, the system controller 21a receives input of the load-side flow rate from the load-side flow rate detector 73, and the bypass pressure difference from the bypass pressure difference detecting unit 90 (measured value B of the bypass pressure difference). The system controller 21a, in accordance with the acquired operation frequency Fp(i) of each of the plurality of refrigeration cycle apparatuses 20, and measured value B of the bypass pressure difference, output the opening degree instruction to the bypass valve 81. The bypass valve 81 adjusts the opening degree in accordance with the opening degree instruction from the system controller 21a. With this configuration, the flow rate of the heat medium flowing from the forward water-side header pipe 41 to the first return water-side header pipe 42a via the bypass pipe 80 is adjusted, so that the difference between the flow rate of the heat medium flowing to each refrigeration cycle apparatus 20 being the heat source apparatus, and the flow rate of the heat medium flowing to each load device 70 is adjusted. By conducting the adjustment as described above, the pressure difference between the forward water-side header pipe 41 and the first return water-side header pipe 42a, in other words, the bypass pressure difference, is adjusted. However, also after the adjustment, the bypass pressure difference is detected by the bypass pressure difference detecting unit 90.

[0035] In the refrigeration cycle system 10 of the present disclosure, the system controller 21a is configured to determine a scale depositing status regarding the scale of the water heat exchanger (heat exchanger 26) based on the state of the heat medium circuit 40. The refrigeration cycle system 10 includes a notification unit 99 configured to issue notification of the result of scale depositing determination by the system controller 21a. Notification unit 99 comprise, for example, a liquid crystal display unit or a speaker, and displays the result of scale depositing determination. For example, an operator of a periodical checkup can know the result of scale depositing determination for the heat exchanger 26 by checking the result displayed on the notification unit 99. The system controller 21 a may have a configuration in which, for example, when determining that scale depositing amount on the heat exchanger 26 exceeds a predetermined threshold, the notification unit 99 may signal it, or notify that cleaning is needed.

[0036] Fig. 3 shows a relation between the head loss and the flow rate of the water heat exchanger (heat exchanger 26) of Fig. 1. Fig. 4 shows a pump head characteristic of the pump (heat source-side pump 30) of Fig. 1. Fig. 5 is a flowchart showing scale depositing determination executed by the system controller 21a of Fig. 1. The following describes one example of the scale depositing determination executed by the system controller 21a in the refrigeration cycle system 10 that adopts a single pump system based on Fig. 3-Fig. 5.

[0037] In the refrigeration cycle system 10 of Embodiment 1, the system controller 21a, by using a detection value of the heat exchanger pressure difference detecting unit 31 (heat exchanger pressure difference APhex(i)) and the detection value of the bypass pressure difference detecting unit 90 (measured value B of the bypass pressure difference) as a state of the heat medium circuit 40, determines the scale depositing status regarding the scale of the heat exchanger 26.

[0038] In Fig. 3, the horizontal axis indicates flow rate [m3 / h] of the heat medium flowing through the water heat exchanger (heat exchanger 26), while the vertical axis indicates the head loss [kPa] of the heat medium at the water heat exchanger (heat exchanger 26). In Fig. 4, the horizontal axis indicates a flow rate Vw of the heat medium that can be delivered by the heat source-side pump 30, while the vertical axis indicates the pump head pressure P. The pump head pressure P is an amount of pressure rise of the heat medium by the heat source-side pump 30 and correspond to a pump head of the heat source-side pump 30. Fig. 4 shows pump head curves C1, C2 and C3 representing the relation between flow rate Vw of the heat medium and the pump head pressure P when the operation frequency Fp of the heat source-side pump 30 is Fp1, Fp2 and Fp3 (Fp1<Fp2<Fp3).

[0039] As shown in Fig. 3, when the flow rate of the heat medium flowing through the heat exchanger 26 increases, the head loss, in other words, the pressure difference between the forwardly and backwardly adjacent positions of the heat exchanger 26 in the heat medium circuit increases. Further, as shown in Fig. 4, the larger flow rate Vw of the heat medium delivered by the heat source-side pump 30 is, the smaller the pump head pressure P is. For the same flow rate Vw, the larger the operation frequency Fp of the heat source-side pump 30 is, the larger the pump head pressure P is. For the same pump head pressure P, the larger the operation frequency Fp of the heat sourceside pump 30 is, the higher the flow rate Vw is.

[0040] The system controller 21a, in activation of the refrigeration cycle system 10 after entering of the system in the practical operation, determines the scale depositing status regarding the scale of the heat exchanger 26 by using the heat exchanger pressure difference APhex(i) detected by the heat exchanger pressure difference detecting unit 31 to calculate the bypass pressure difference, and comparing the difference Dab between calculated value A of the calculated bypass pressure difference and measured value B of the bypass pressure difference detected by the bypass pressure difference detecting unit 90 with a difference value stored in advance (difference Dab_0 between calculated value A and measured value B obtained, for example, under initial conditions, such as those during a test run). Specifically, the system controller 21a, when the difference upon activation of the system deviates from a difference value stored in advance by equal to or greater than a certain amount, determines that equal to or greater than a certain amount of the scale has deposited on the heat exchanger 26, and notifies it by the notification unit 99.

[0041] To enable calculation of calculated value A of the bypass pressure difference based on the heat exchanger pressure difference APhex(i) detected by the heat exchanger pressure difference detecting unit 31, characteristics of the heat exchanger 26 shown in Fig. 3, and pump head characteristics of the heat source-side pump 30 shown in Fig. 4 are stored in advance in the system controller 21a in the form of tables or formulae.

[0042] For example, the relation between the head loss in the heat exchanger 26 (in other words, heat exchanger pressure difference APhex(i)) and the flow rate Vw of the heat medium are stored in the form of Formula (1) below. In Formula (1), f1 (APhex(i)) is a function of heat exchanger pressure difference APhex(i). The indices(i) of each parameter denote the number of refrigeration cycle apparatuses 20. The flow rate of the heat medium flowing through the heat exchanger 26 is a flow rate of the heat medium flowing through the heat source-side pump 30, while being a flow rate of the heat medium flowing through the refrigeration cycle apparatus 20 being the heat source apparatus.

[0043] Vw(i) =f1 (APhex(i)) ...(1)

[0044] Further, for example, the relation among the operation frequency Fp of the heat source-side pump 30 (in other words, the rotation speed), the flow rate Vw (i) and the pump head pressure P (in other words, pump head APp(i)) are stored in the form of Formula (2) below. In Formula (2), f2 (Fp, Vw(i)) is a function of the operation frequency Fp of the heat source-side pump 30 and flow rate Vw (i).

[0045] APp(i) =f2 (Fp, Vw(i)) ...(2)

[0046] As shown in Fig. 1, in a configuration in which the refrigeration cycle system 10 includes a plurality of refrigeration cycle apparatuses 20, the refrigeration cycle system 10 includes the heat exchanger pressure difference detecting unit 31. The number of the provided heat exchanger pressure difference detecting unit 31 is the same as the number of refrigeration cycle apparatuses 20 (see Fig. 2). In this case, the system controller 21a employs the heat exchanger pressure differences APhex(i) detected by the plurality of heat exchanger pressure difference detecting unit 31 and measured value B of the bypass pressure difference detected by one bypass pressure difference detecting unit 90 for the scale depositing determination.

[0047] (Upon test run of the refrigeration cycle system 10) Upon a test run right after assembling of the refrigeration cycle system 10, no scale has deposited on the water heat exchanger (heat exchanger 26). In the initial condition, the system controller 21a, acquires a heat exchanger pressure difference APhex(i) detected by the heat exchanger pressure difference detecting unit 31 and the operation frequency Fp of the heat source-side pump 30 of the controller 21 from each of the plurality of refrigeration cycle apparatuses 20. The system controller 21a receives input of measured value B of the bypass pressure difference from the bypass pressure difference detecting unit 90. The system controller 21a calculates the flow rate of the heat medium flowing within the heat exchanger 26, that is, flow rate Vw(i) of the heat medium flowing through the refrigeration cycle apparatus 20 by using Formula (1) based on the acquired heat exchanger pressure difference APhex(i). The system controller 21 a calculates pump head APp(i) by using Formula (2) based on the calculated flow rate Vw (i) and the acquired operation frequency Fp of the heat sourceside pump 30 (in other words, rotation speed). The system controller 21a, for each of the plurality of refrigeration cycle apparatuses 20, calculate the above-described pump head APp(i) by using Formula (1) and Formula (2). The system controller 21a obtains the mean value of the difference between pump head APp(i) at each refrigeration cycle apparatus 20 and the heat exchanger pressure difference APhex(i) by using Formula (3) below, and determines the obtained mean value as calculated value A of the bypass pressure difference.

[0048] A=Ave(APp(i) -APhex(i)) ...(3)

[0049] In other words, calculated value A of the bypass pressure difference is an average for all the heat source-side branch pipes 40a of the pressure differences, each being a pressure difference (APp(i) -APhex(i)) at heat source-side branch pipe 40a between forwardly and backwardly adjacent positions of the refrigeration cycle apparatus 20 in the heat medium circuit. Then, the system controller 21a calculates a difference between calculated value A of the bypass pressure difference obtained by using Formula (3), in other words, a bypass pressure difference calculated based on a state of the heat source-side part of the circuit of the heat medium circuit 40, and measured value B of the bypass pressure difference directly detected at the bypass pressure difference detecting unit 90, and stores them as the difference Dab_0 under the initial condition.

[0050] (In activation of the refrigeration cycle system 10) In activation of the refrigeration cycle system 10 after entering the practical operation, scale depositing amount on the heat exchanger 26 gradually increases. In activation of the refrigeration cycle system 10 after entering the practical operation, the system controller 21a, being similar to the test run, acquires each heat exchanger pressure difference APhex(i) and measured value B of the bypass pressure difference, calculates calculated value A of the bypass pressure difference, to obtain the difference between calculated value A and measured value B. Then, in activation of the refrigeration cycle system 10 after entering the practical operation, the system controller 21a determines the scale depositing status of the scale for the plurality of heat exchangers 26 by comparing the difference obtained upon activation and the difference obtained at the initial condition.

[0051] Referring to Fig. 5, the flow of the scale depositing determination executed by the system controller 21a in activation of the refrigeration cycle system 10 after entering the practical operation will be described. Upon activation of the refrigeration cycle system 10, the system controller 21a acquires heat exchanger pressure difference APhex(i) detected by the heat exchanger pressure difference detecting unit 31 from the controller 21 of each of the plurality of refrigeration cycle apparatuses 20 (step S10). The system controller 21a acquires operation frequency Fp of the heat source-side pump 30 from the controller 21 of each of the plurality of refrigeration cycle apparatuses 20. The system controller 21a receives input of measured value B of the bypass pressure difference from the bypass pressure difference detecting unit 90.

[0052] The system controller 21a, for each refrigeration cycle apparatus 20, calculates flow rate Vw(i) of the heat medium flowing through the heat exchanger 26, that is, the flow rate of the heat medium flowing through the refrigeration cycle apparatus 20 based on acquired heat exchanger pressure difference APhex(i) by using Formula (1) (step S11). The system controller 21a calculates pump head APp(i) by using Formula (2) based on flow rate Vw (i) calculated in step S11, and acquired operation frequency Fp of the heat source-side pump 30 (step S12). The system controller 21a performs the calculation of steps S11 and S12 for each refrigeration cycle apparatus 20, and obtains calculated value A of the bypass pressure difference by using Formula (3) based on pump head APp(i) calculated in step S12 and heat exchanger pressure difference APhex(i) acquired in step S10 (step S13).

[0053] Calculated value A of the bypass pressure difference obtained here reflects the state of the flow passage of the heat medium in the heat exchanger 26 of each of the plurality of refrigeration cycle apparatuses 20. When the scale depositing amount on the heat exchanger 26 increases at the plurality of refrigeration cycle apparatuses 20, head loss of the heat medium in the heat exchanger 26 (in other words, heat exchanger pressure difference APhex(i)) increases due to friction, or other causes, the flow rate [m3 / h] increases, the pump head pressure P of the heat source-side pump 30 (in other words, pump head APp(i)) decreases. Therefore, when the amount of depositing scales increases, pump head APp(i) decreases, and heat exchanger pressure difference APhex(i) increases, so that calculated value A of the bypass pressure difference decreases.

[0054] The system controller 21a calculates difference Dab between calculated value A of the bypass pressure difference obtained by calculating in step S13 and measured value B of the bypass pressure difference input from the bypass pressure difference detecting unit 90 (step S14). The system controller 21a determines whether the difference Dab obtained upon activation deviates by equal to or greater than a certain amount from the difference value stored in advance (in other words, difference Dab_0 acquired with the initial condition) (step S15). When difference Dab upon activation of the system deviates by equal to or greater than a certain amount from difference Dab_0 under the initial condition (step S15; YES), the system controller 21a determines that equal to or greater than a certain amount of the scale has deposited on each of the plurality of heat exchangers 26 of the refrigeration cycle system 10 and issues notification by the notification unit 99, etc. (step S16).

[0055] Here, the case where the difference Dab upon activation of the system deviates by equal to or greater than a certain amount from the difference Dab_0 under the initial condition can be determined by a value obtained by subtracting difference Dab_0 under the initial condition from the difference upon activation of the system based on the absolute value thereof, irrespective of the positive or negative sign.

[0056] As described above, the refrigeration cycle system 10 of Embodiment 1 being a single pump system, in activation after entering the practical operation the system controller 21a, calculates difference Dab between calculated value A and measured value B of the bypass pressure difference, and compares calculated difference Dab upon activation of the system with difference Dab_0 under the initial condition calculated in advance upon a test run and stored, so that it can determine the chronical scale depositing status of the scale on the heat exchanger 26 based on the comparison result.

[0057] Further, the determination criteria for determining that equal to or greater than a certain amount of scales has deposited on each of the plurality of heat exchangers 26 of the refrigeration cycle system 10 may be, for example, by learning difference Dab, making determination based on learned difference Dab. In this case, the system controller 21a has a function to store and learn calculated value A, measured value B and difference Dab therebetween. The system controller 21a, in the process of operating the refrigeration cycle system 10, learns difference Dab, and executes the determination of scale depositing status of scales based on learned difference Dab.

[0058] The method for determining the scale depositing status of the heat exchanger 26 is not limited to the example of Fig. 5. In the example of Fig. 5, pump head APp(i) of the heat source-side pump 30 is calculated based on the heat exchanger pressure difference APhex(i) detected by the heat exchanger pressure difference detecting unit 31, the bypass pressure difference is calculated based on heat exchanger pressure difference APhex(i) and calculated pump head △Pp(i), and the depositing status of scales is determined based on difference Dab between calculated value A of the calculated bypass pressure difference, and measured value B of the bypass pressure difference detected by the bypass pressure difference detecting unit 90. Hereafter, a method is described in which, instead of measured value B, calculated value C obtained with a method different from that of calculated value A, is compared with calculated value A to determine the depositing status of scales.

[0059] Fig. 6 is a circuitry diagram showing a modification of the refrigeration cycle apparatus 20 of Fig. 2. In Fig. 6, void arrows with solid edges each indicate the direction in which the refrigerant flows, while the void arrows with dashed edges each indicate the direction in which the heat medium flows.

[0060] In the refrigeration cycle apparatus 20 of Fig. 6, a heat source-side branch pipe 40a is provided with a heat exchanger pressure difference detecting unit 31 configured to detect a pressure difference between pressures at forwardly and backwardly adjacent positions respectively of the heat exchanger 26 in the heat medium circuit, and a pump pressure difference detecting unit 32 configured to detect a pump pressure difference being a pressure difference between pressures at forwardly and backwardly adjacent positions respectively in the heat medium circuit of the heat source-side pump 30 (in other words, pump head). The pump pressure difference detecting unit 32 is, for example, a differential pressure gauge. In the example of Fig.6, the heat exchanger pressure difference detecting unit 31 may be referred to as a first detecting unit, and the pump pressure difference detecting unit 32 may be referred to as a second detecting unit. Instead of employing a differential pressure gauge as a pump pressure difference detecting unit 32, two pressure sensors provided at forwardly and backwardly adjacent positions in the heat medium circuit of the heat source-side pump 30 may be used.

[0061] The system controller 21a obtains the bypass pressure by using Formula (4) below, to obtain calculated value C. Pump head APp(i) being a parameter of calculated value A has been calculated from heat exchanger pressure difference APhex(i) detected by the heat exchanger pressure difference detecting unit 31 by using Formula (1) and Formula (2). However, APp_a(i) in Formula (4) calculated for acquiring value C is a measured value of pump head directly detected by the pump pressure difference detecting unit 32.

[0062] C=Ave(APp_a(i) -APhex(i)) ...(4)

[0063] Upon test run of the refrigeration cycle system 10, the system controller 21a calculates each of calculated value A of the bypass pressure difference and calculated value C, calculates the difference thereof and stores it as difference Dac_0 at the initial condition. Upon activation of the refrigeration cycle system 10 after entering the practical operation, the system controller 21a calculates each of calculated value A of the bypass pressure difference and calculated value C, calculates difference Dac, and compares difference upon activation of the system Dac with difference Dac_0 at the initial condition, to determine the scale depositing status regarding the scale of the heat exchanger 26.

[0064] As described above, in a configuration in which the heat exchanger pressure difference detecting unit 31 and the pump pressure difference detecting unit 32 are employed to execute scale depositing determination, second detecting units (pump pressure difference detecting units 32) of the number corresponding to the number of the provided refrigeration cycle apparatuses 20 . On the other hand, as described above, as shown in Fig. 1 -Fig. 5, in the configuration in which the heat exchanger pressure difference detecting unit 31 and the bypass pressure difference detecting unit 90 are employed for scale depositing determination, one second detecting unit (bypass pressure difference detecting unit 90 of Fig. 1) suffices irrespective of the number of refrigeration cycle apparatuses 20, so that the configuration of the refrigeration cycle system 10 can be simplified.

[0065] As described above, the refrigeration cycle system 10 according to Embodiment 1 includes, a refrigerant circuit 27 that includes a compressor 22 and in which refrigerant is caused to circulate by the compressor 22, a heat medium circuit 40 including a heat source-side pump 30, in which a heat medium is caused to circulate the heat source-side pump 30, a heat exchanger 26 configured to cause the refrigerant and the heat medium to exchange heat with each other, and a system controller 21a configured to control a heat source-side pump 30, wherein the heat medium circuit 40 includes a load device 70 provided downstream of the heat exchanger 26, a bypass pipe 80 bypassing the load device 70. Further, the refrigeration cycle system 10 includes a first detecting unit (heat exchanger pressure difference detecting unit 31) provided in the medium circuit 40, and configured to detect a pressure difference between pressures at forwardly and backwardly adjacent positions respectively of the heat exchanger 26 in the heat medium circuit, a second detecting unit (bypass pressure difference detecting unit 90) provided at the heat medium circuit 40, and configured to detect a bypass pressure difference between forwardly and backwardly adjacent positions in the heat medium circuit of the bypass pipe 80. The system controller 21a is configured to obtain pump head (APp(i)) of the heat source-side pump 30 from the pressure difference (heat exchanger pressure difference APhex(i)) detected by the first detecting unit and the rotation speed (for example, operation frequency Fp) of the heat source-side pump 30, and calculate a bypass pressure difference between forwardly and backwardly adjacent positions of the bypass pipe 80 in the heat medium circuit based on the pressure difference (heat exchanger pressure difference APhex(i)) and the pump head (APp(i)). The system controller 21a determines the scale depositing status regarding the scale of the heat exchanger 26 by comparing difference Dab between calculated value A of the calculated bypass pressure difference and measured value B of the bypass pressure difference detected by the second detecting unit with the difference value stored in advance (for example, difference Dab_0 under the initial condition).

[0066] As described above, in the refrigeration cycle system 10 according to Embodiment 1, the depositing status of scales on the heat exchanger 26 is determined by comparing difference Dab between calculated value A and measured value B of the bypass pressure difference obtained by using the first detecting unit and the second detecting unit provided at the heat medium circuit 40 through different methods with the difference value stored in advance. Since both the first detecting unit and the second detecting unit are provided at the heat medium circuit 40 in which scales deposit, in the configuration of the present disclosure in which the scale depositing status regarding the scale of the heat exchanger 26 is determined based on difference Dab between calculated value A and measured value B of the bypass pressure difference obtained by using their detection values (heat exchanger pressure difference APhex(i) and measured value B of the bypass pressure difference), more accurate determination can be executed in which fluctuation of load and change in operating conditions less affect the determination accuracy compared to conventional configurations in which the depositing status of scales of the heat exchanger is determined based on the temperature difference between the saturation temperature of the refrigerant and the temperature of the heat medium flowing out of the heat exchanger.

[0067] Further, in the modification of Fig. 6, the refrigeration cycle system 10 includes a, a refrigerant circuit 27 including a compressor 22 being configured to circulate refrigerant in the refrigerant circuit, a heat medium circuit 40 including a heat sourceside pump 30 configured to circulate a heat medium in the heat medium circuit, a heat exchanger 26 configured to cause the refrigerant and the heat medium to exchange heat with each other, and a system controller 21a configured to control the heat source-side pump 30 wherein the heat medium circuit 40 includes a load device 70 provided downstream of the heat exchanger 26, and a bypass pipe 80 bypassing the load device 70. Further, the refrigeration cycle system 10 includes a first detecting unit (heat exchanger pressure difference detecting unit 31) provided at the heat medium circuit 40, and configured to detect the pressure difference between pressures at forwardly and backwardly adjacent positions respectively of the heat exchanger 26 in the heat medium circuit, and a second detecting unit (pump pressure difference detecting unit 32) provided at the heat medium circuit 40 and configured to detect pump pressure difference of the heat source-side pump 30 being pressure difference between pressures at forwardly and backwardly adjacent positions respectively in the heat medium circuit. The system controller 21 a obtains the pump head (APp(i)) of the heat source-side pump 30 from the pressure difference (heat exchanger pressure difference △Phex(i)) detected by the first detecting unit and the rotation speed (for example, operation frequency Fp) of the heat source-side pump 30, to calculate the bypass pressure difference between the forwardly and backwardly adjacent positions of bypass pipe in the heat medium circuit based on the pressure difference (heat exchanger pressure difference APhex(i)) and the pump head (APp(i)) to obtain a first calculated value (calculated value A), as well as calculating the bypass pressure difference forwardly and backwardly adjacent positions of the bypass pipe 80 in the heat medium circuit based on the pressure difference (heat exchanger pressure difference APhex(i)) detected by the first detecting unit and the pump pressure difference detected by the second detecting unit (measured value APp_a(i) of pump head) to obtain the second calculated value (calculated value C). The system controller 21a then compares difference Dacb between the first calculated value (calculated value A) and the second calculated value (calculated value C) of the bypass pressure difference with the difference value stored in advance (Dac_0 at the initial condition) to determine the scale depositing status regarding the scale of the heat exchanger 26.

[0068] As described above, in the modification of Fig. 6, the depositing status of scales on the heat exchanger 26 is determined by comparing difference Dac between the first calculated value (calculated value A) and the second calculated value (calculated value C) of the bypass pressure difference obtained by using the first detecting unit and the second detecting unit provided at the heat medium circuit 40 and obtained through different methods, with a difference value stored in advance (difference Dac_0 at the initial condition). Since both the first detecting unit and the second detecting unit are provided at the heat medium circuit 40 in which scales deposit, in the configuration of the present disclosure in which the scale depositing status regarding the scale of the heat exchanger 26 is determined based on difference Dac between the first calculated value and the second calculated value of the bypass pressure difference obtained by using their detection values (heat exchanger pressure difference APhex(i) and a measured value APp_a(i) of pump head), fluctuation of load and change in operating conditions less affect the determination accuracy as compared to conventional configurations in which the depositing status of scales of the heat exchanger is determined based on the temperature difference between the saturation temperature of the refrigerant and the temperature of the heat medium flowing out the heat exchanger, so that accurate determination can be performed.

[0069] The system controller 21a stores difference Dac_0 calculated in the initial condition in which no scale has deposited on the heat exchanger 26 as a difference value stored in advance. Therefore, since it is possible to execute scale depositing determination upon activation of the system by using the initial condition obtained on the configuration of the refrigeration cycle system, determination accuracy increases.

[0070] The refrigeration cycle system 10 includes a plurality of refrigeration cycle apparatuses 20 each including a refrigerant circuit 27, a heat source-side pump 30 and a heat exchanger 26, wherein the heat medium circuit 40 includes a plurality of heat source-side branch pipes 40a to which a heat source-side pump 30 and a heat exchanger 26 of each refrigeration cycle apparatus 20 are provided, and the plurality of heat source-side branch pipes 40a are connected in parallel with each other and are connected to the load-side.

[0071] In this way, even in a case where the refrigeration cycle system 10 includes a plurality of refrigeration cycle apparatuses 20, in the same way as the case where the refrigeration cycle system 10 includes only one refrigeration cycle apparatus 20, the state of the heat medium circuit 40 can be determined based on the scale depositing status regarding the scale of the plurality of heat exchangers 26.

[0072] Further, the refrigeration cycle system 10 includes a notification unit 99 having a display unit or a speaker. The system controller 21a is configured to notify that scale has deposited by the notification unit 99 when difference Dab(or difference Dac) deviates from a difference value stored in advance by equal to or greater than a certain amount.

[0073] With this configuration, for example, an operator of a periodical checkup can know equal to or greater than a certain amount of scales has deposited on the heat exchanger 26, and upon notification, can take a measure such as cleaning of the heat exchanger 26. Therefore, emergence of abnormality, such as clogging of or extreme decline of heat exchange efficiency of the heat exchanger 26 due to scale deposition, can be avoided.

[0074] Embodiment 2. Fig. 7 is a circuitry diagram showing a general schematic configuration of the refrigeration cycle system 110 according to Embodiment 2 of the present disclosure. While the refrigeration cycle system 10 of Embodiment 1 adopts a single pump system, the refrigeration cycle system 110 of Embodiment 2 of adopts a multi-pump system. In the refrigeration cycle system 110 of Embodiment 2, a second detecting unit employed for determination of the scale depositing status is different from that of Embodiment 1. Based on Fig. 7, the circuit configuration of the refrigeration cycle system 110 of Embodiment 2 will be described. In Embodiment 2, for components and configurations same as Embodiment 1, same signs are attached and the explanation therefore are omitted. Differences from Embodiment 1 will be the focus of the following explanation.

[0075] As shown in Fig. 7, in the refrigeration cycle system 110 in which a multi-pump system is adopted, a pump is provided at each of the heat source-side part of the circuit and the load-side part of the circuit of the heat medium circuit 140. Hereafter, a pump provided at the heat source-side part of the circuit is referred to as a heat source-side pump 30, while a pump provided at the load-side part of the circuit is referred to as a load-side pump 144. In Embodiment 2, a pipe that bypasses the load-side part of the circuit, in other words, a pipe that bypasses the plurality of load devices 70 in the heat medium circuit 140 is a free bypass pipe 180 without a bypass valve 81 (see Fig. 1).

[0076] The configuration of the heat source-side part of the circuit in the heat medium circuit 140 is same as Embodiment 1 shown in Fig. 1. The heat source-side part of the circuit includes a plurality of heat source-side branch pipes 140a to each of which the heat exchanger 26 and heat source-side pump 30 are provided, a first return water-side header pipe 142a to which each upstream end part of the plurality of heat source-side branch pipes 140a is connected, and a first forward water-side header pipe 141a to which each downstream end part of plurality of heat source-side branch pipes 140a is connected.

[0077] Being similar to the case of Embodiment 1 shown in Fig. 1, the load-side part of the circuit of the heat medium circuit 140, a plurality of load-side branch pipes 140b to each of which a load device 70 and a load-side expansion valve 71 are provided, a second return water-side header pipe 142b to each of which a downstream end part of each of the plurality of load-side branch pipes 140b is connected, a merger section pipe 140c connecting the second return water-side header pipe 142b with the first return water-side header pipe 142a of the heat source apparatus side, and a load-side flow rate detector 73 provided at the merger section pipe 140c. In the heat medium circuit 140 of the Embodiment 2, the forward water-side header pipe 141 includes a heat source apparatus (refrigeration cycle apparatus 20) side first forward water-side header pipe 141a, and a load device 70 side second forward water-side header pipe 141b, and the first forward water-side header pipe 141a and the second forward water-side header pipe 141b are connected by the connecting pipe 140d to which load-side pump 144 is connected.

[0078] In the example of Fig. 7, the refrigeration cycle system 10 is configured to distribute the heat medium cooled by four refrigeration cycle apparatuses 20 to two load devices 70 and circulate it. Specifically, the heat medium circuit 40 is configured such that the four heat source-side branch pipes 40a, the first forward water-side header pipe 141a, the three connecting pipes 140d, the second forward water-side header pipe 141b, the two load-side branch pipes 140b, the second return water-side header pipe 142b, the merger section pipe 140c, and the first return water-side header pipe 142a are connected sequentially. Each of two connecting pipes 140d of the three connecting pipes 140d is provided with a load-side pump 144 configured to pump the heat medium to a second forward water-side header pipe 141b on the load-side from the first forward water-side header pipe 141 a on the heat source-side. At the rest of the three connecting pipes 140d, that is, the one connecting pipe 140d a forward waterside expansion valve 145 being, for example, a proportion two-way valve is provided.

[0079] The system controller 21a is connected to the load-side flow rate detector 73, a load-side flow rate detected by the load-side flow rate detector 73 is input to the system controller 21a. To the system controller 21 a are connected each of the load-side pump 144 and the forward water-side expansion valve 145, and the system controller 21a is configured to control the frequency of the load-side pump 144 and the opening degree of the forward water-side expansion valve 145.

[0080] In the heat medium circuit 140, the free bypass pipe 180 connects the first forward water-side header pipe 141a and the first return water-side header pipe 142a being both end parts of the heat source-side part of the circuit. The free bypass pipe 180, when the flow rate of the heat medium flowing through each water heat exchanger (heat exchanger 26) is greater than the flow rate of the heat medium flowing through each load device 70, causes the heat medium of the amount corresponding to the difference between the flow rates to flow from the first forward water-side header pipe 141a to the first return water-side header pipe 142a while bypassing the two load devices 70.

[0081] Further, in the refrigeration cycle system 110 of Embodiment 2, being similar to Embodiment 1, the system controller 121a determines the scale depositing status of the water heat exchanger (heat exchanger 26) based on the state of the heat medium circuit 140. In Embodiment 1, as the state of the heat medium circuit 40, a pressure difference between pressures at forwardly and backwardly adjacent positions of the heat exchanger 26 in the heat medium circuit detected by the heat exchanger pressure difference detecting unit 31 and a bypass pressure difference between forwardly and backwardly adjacent positions of the bypass pipe 80 in the heat medium circuit detected by the bypass pressure difference detecting unit 90 are used. In Embodiment 2, as the state of the heat medium circuit 40, a pressure difference between pressures at forwardly and backwardly adjacent positions of the heat exchanger 26 in the heat medium circuit detected by the heat exchanger pressure difference detecting unit 31 and a flow rate of the heat medium flowing in the load-side and detected by the loadside flow rate detector 73 (hereafter referred to as a load-side flow rate) are used. In other words, in Embodiment 2 the first detecting unit corresponds to the heat exchanger pressure difference detecting unit 31, and the second detecting unit corresponds to the load-side flow rate detector 73.

[0082] (Upon test run of the refrigeration cycle system 110) Upon a test run right after assembling of the refrigeration cycle system 110, no scale deposits on the water heat exchanger (heat exchanger 26). In this initial condition, the system controller 121a acquires pressure difference between pressures at forwardly and backwardly adjacent positions respectively of the heat exchanger 26 in the heat medium circuit detected by their respective heat exchanger pressure difference detecting units 31 (heat exchanger pressure difference △Phex(i)) from the controller 21 of each of plurality of refrigeration cycle apparatuses 20. The system controller 121a receives input of the measured value FB of the load-side flow rate detected by the load side flow rate detector 73.

[0083] The system controller 121a, first, obtains calculated value A of the bypass pressure difference by using Formula (1) to Formula (3), from acquired plurality of heat exchanger pressure differences APhex(i). In other words, the system controller 21 a uses Formula (1) to obtain the flow rate of the refrigerant flowing within the heat exchanger 26, in other words, flow rate Vw (i) in the refrigeration cycle apparatus 20 from the acquired heat exchanger pressure difference APhex(i), obtains pump head APp(i) from flow rate Vw (i) by using Formula (2), and obtains calculated value A of the bypass pressure difference by using Formula (3) from pump head APp(i) and heat exchanger pressure difference APhex(i).

[0084] Then, the system controller 121a obtains bypass flow rate of the heat medium flowing through the free bypass pipe 180 from Formula (5) below to obtain calculated value BFa by using calculated value A of the bypass pressure difference and Cv value of the free bypass pipe 180 learned in advance (hereafter, Cv).

[0085] BFa=Cvx(A[kPa]A0.5) ...(5)

[0086] Here, for Cv value of the free bypass pipe 180, already-learned Cv value obtained by learning Cv value is acquired upon a test run. Cv value of the free bypass pipe 180 doesn’t vary essentially expect for a special condition such as a failure, those learned upon a test run can be used after activation in practical operation.

[0087] Further, the system controller 121a obtains a load-side flow rate being a flow rate of the heat medium flowing on the load-side from Formula (6) below by using calculated value BFa of the bypass flow rate, and flow rate Vw(i) of the heat medium flowing through each of the refrigeration cycle apparatuses 20, to obtain calculated value FA. Specifically, calculated value FA of the flow rate of the heat medium flowing in the loadside is obtained by subtracting calculated value BFa of the bypass flow rate obtained by using Formula (5) from the total flow rate of the flow rate Vw(i) of the heat medium flowing to each refrigeration cycle apparatus 20 for all the refrigeration cycle apparatuses 20 of the refrigeration cycle system 10.

[0088] FA=Total(Vw(i)) -BFa...(6)

[0089] The system controller 21a calculates the difference between calculated value FA of the load-side flow rate obtained by using Formula (6), in other words, the load-side flow rate obtained from the state of the heat source-side part of the circuit of the heat medium circuit 40, and measured value FB of the load-side flow rate detected by the load-side flow rate detector 73, and stores the calculated difference as difference Dfab_0 at the initial condition.

[0090] (Upon activation of the refrigeration cycle system 110) In activation of the refrigeration cycle system 110 after entering the practical operation, the scale depositing amount on the heat exchanger 26 gradually increases. In activation of the refrigeration cycle system 110 after entering the practical operation, the system controller 121a, being similar to the test run, acquires each heat exchanger pressure difference APhex(i) and the measured value FB of the load-side flow rate, and obtains calculated value FA of the load-side flow rate, to obtain difference Dfab between calculated value FA and measured value FB. Then, in activation of the refrigeration cycle system 110 after entering the practical operation, the system controller 121a determines the scale depositing status of the scale for the plurality of heat exchangers 26 by comparing difference obtained upon activation Dfab with difference Dfab_0 obtained upon a test run.

[0091] Fig. 8 is a flowchart showing the scale depositing determination executed by the system controller 121a of Fig. 7. Referring to Fig. 8, the flow of the scale depositing determination executed by the system controller 121a in activation of the refrigeration cycle system 110 after entering the practical operation of the system will be described. Upon activation of the refrigeration cycle system 110, the system controller 121a acquires heat exchanger pressure difference APhex(i) detected by the heat exchanger pressure difference detecting unit 31 (see Fig. 2) from the controller 21 of each of plurality of refrigeration cycle apparatuses 20 (step S20). Further, the system controller 121a acquires the operation frequency Fp of the heat source-side pump 30 (in other words, rotation speed) from the controller 21 of each of plurality of refrigeration cycle apparatuses 20. The system controller 121a receives input of load-side a flow rate of heat medium flowing through the load-side of the merger section pipe 40c, in other words, measured value FB of the load-side flow rate from the load-side flow rate detector 73.

[0092] The system controller 121a, for each refrigeration cycle apparatus 20, calculates the flow rate of the heat medium flowing through the heat exchanger 26, that is, flow rate Vw(i) of the heat medium flowing through the refrigeration cycle apparatus 20 from heat exchanger pressure difference APhex(i) by using Formula (1) (step S21). Further, the system controller 121a calculates pump head APp(i) by using Formula (2) based on flow rate Vw (i) calculated in step S21, and acquired operation frequency Fp of the heat source-side pump 30 (in other words, rotation speed) (step S22). The system controller 121a, for each refrigeration cycle apparatus 20, performs calculation of step S11 and S22, obtains calculated value A of the bypass pressure difference by using Formula (3) based on pump head APp(i) calculated in step S22 and heat exchanger pressure difference APhex(i) acquired in step S20 (step S23). The system controller 121a obtains bypass flow rate, by using Formula (5) from calculated value A of the bypass pressure difference, and Cv value of the free bypass pipe 180 learned in advance to obtain calculated value BFa (step S23). The system controller 121a, for each refrigeration cycle apparatus 20, obtains load-side flow rate by using Formula (6) based on flow rate Vw (i) calculated in step S21, and calculated value BFa of the bypass flow rate calculated in step S23, to obtain calculated value FA (step S24).

[0093] The calculated value FA of the load-side flow rate obtained here reflects the state of the flow passage of the heat medium in the heat exchanger 26 of each of the plurality of refrigeration cycle apparatuses 20. When the amount of depositing scales increases on the heat exchanger 26 of each of the plurality of refrigeration cycle apparatuses 20, friction or other factor causes head loss of the heat medium in the heat exchanger 26 (in other words, heat exchanger pressure difference APhex(i)) increases, so that flow rate [m3 / h] increases, while pump head pressure P of the heat source-side pump 30 (in other words pump head APp(i)) decreases. Therefore, when the amount of scales depositing increases, pump head APp(i) decreases, and heat exchanger pressure difference APhex(i) increases, so that calculated value A of the bypass pressure difference decreases, while calculated value FA of the load-side flow rate increases.

[0094] The system controller 121a obtains difference Dfab between calculated value FA of the load-side flow rate calculated in step S24, and measured value FB of the loadside flow rate detected by the load-side flow rate detector 73 (step S25). Then, the system controller 121a determine whether difference Dfab obtained upon activation of the system deviates from difference Dfab_0 stored in advance (in other words, difference Dfab_0 acquired at the initial condition) by equal to or greater than a certain amount (step S26). When difference upon activation of the system Dfab deviates by equal to or greater than a certain amount from difference Dfab_0 at the initial condition (step S26; YES), the system controller 121a determines that equal to or greater than a certain amount of the scale has deposited on each of the plurality of heat exchangers 26 of the refrigeration cycle system 110 and issues notification by the notification unit 99, etc. (step S27).

[0095] Here, the case where difference upon activation of the system Dfab deviates by equal to or greater than a certain amount from difference Dfab at the initial condition may be determined from the absolute value of the obtained value, being obtained by subtracting difference Dfab_0 at the initial condition from difference upon activation of the system Dfab, irrespective of the positive or negative sign.

[0096] As described above, in the refrigeration cycle system 110 of Embodiment 2 being of a multi-pump system, in activation after entering the practical operation, the system controller 21a calculates difference Dfab between calculated value FA and measured value FB of the load-side flow rate, and compares calculated difference upon activation of the system Dfab with difference Dfab_0 at the initial condition calculated and stored in advance upon a test run, so that it can determine the chronical scale depositing status of the scales on the heat exchanger 26 based on the comparison result.

[0097] Instead of the measured value FB of the load-side flow rate, scale depositing determination can be executed by using calculated value FC of the load-side flow rate obtained by a method different from that for calculated value FA. For example, as shown in Fig. 6, the heat exchanger pressure difference detecting unit 31 and the pump pressure difference detecting unit 32 are provided at the heat source-side branch pipe 40a of each refrigeration cycle apparatus 20, and calculated value FC of the load-side flow rate is obtained from Formulae (4) -(6), by using their detection values. The system controller 121a calculates difference Dfac between calculated value FA of the load-side flow rate obtained by using Formulae (1) -(3), (5), and (6) and calculated value FC of the load-side flow rate, and when difference Dfac deviates by equal to or greater than a certain amount from difference Dfac_0 calculated upon a test run, determines that equal to or greater than a certain amount of the scale has deposited on each of the plurality of heat exchangers 26 of the refrigeration cycle system 110, and issues notification of it by the notification unit 99, etc.

[0098] As described above, the refrigeration cycle system 110 according to Embodiment 2 includes a refrigerant circuit 27 including a compressor 22 configured to circulate refrigerant, a heat medium circuit 40 including a heat source-side pump 30 and a loadside pump 144, the heat source-side pump 30 and the load-side pump 144 being configured to circulate the heat medium, a heat exchanger 26 configured to cause the refrigerant and the heat medium to exchange heat with each other, and a system controller 121a configured to control the heat source-side pump 30. The heat medium circuit 40 incudes a load device 70 provided downstream of the heat exchanger 26, and a free bypass pipe 180 that bypasses the load device 70. The heat source-side pump 30 is configured to pump the heat medium to the heat exchanger 26, and the load-side pump 144 is configured to pump the heat medium to the load device 70. Further, the refrigeration cycle system 110 includes a first detecting unit (heat exchanger pressure difference detecting unit 31) provided at the heat medium circuit 40 and configured to detect a pressure difference between pressures at forwardly and backwardly adjacent positions respectively of the heat exchanger 26 in the heat medium circuit, and a second detecting unit (load-side flow rate detector 73), provided at a load-side of the heat medium circuit 40 and configured to detect a load-side flow rate of the heat medium. The system controller 121a obtains pump head (APp(i)) of the heat sourceside pump 30 from the pressure difference (heat exchanger pressure difference △Phex(i)) detected by the first detecting unit, and the rotation speed (for example, operation frequency Fp) of the heat source-side pump 30, and calculates the load-side flow rate of the heat medium flowing on the load-side of the heat medium circuit 40 based on the pressure difference (heat exchanger pressure difference APhex(i)) and the pump head (APp(i)). The system controller 121a compares the difference Dfab between calculated value FA of the load-side flow rate and measured value FB of the load-side flow rate detected by the second detecting unit with a difference value stored in advance (for example, difference Dfab_0 at the initial condition), to determine the scale depositing status regarding the scale of the heat exchanger 26.

[0099] As described above, in the refrigeration cycle system 110 according to Embodiment 2, depositing status of scales on the heat exchanger 26 is determined by comparing difference Dfab between calculated value A of the load-side flow rate and measured value B obtained by the first detecting unit and the second detecting unit provided at the heat medium circuit 40 through different methods with a difference value stored in advance. Since both the first detecting unit and the second detecting unit are provided at the heat medium circuit 40 in which scales deposit, in the configuration of the present disclosure in which the scale depositing status regarding the scale of the heat exchanger 26 is determined based on difference Dfab between calculated value FA and measured value FB of the load-side flow rate obtained by using their detection values (heat exchanger pressure difference APhex(i) and measured value FB of the load-side flow rate), more accurate determination can be executed in which fluctuation of load and change in operating conditions less affect the determination accuracy compared to conventional configurations in which the depositing status of scales of the heat exchanger is determined based on the temperature difference between the saturation temperature of the refrigerant and the temperature of the heat medium flowing out of the heat exchanger.

[0100] The modification of the refrigeration cycle system 110 of Embodiment 2 (see Fig. 6), includes a refrigerant circuit 27 including a compressor 22 configured to circulate refrigerant, a heat medium circuit 40 that includes a heat source-side pump 30 and a load-side pump 144, configured to circulate a het medium, a heat exchanger 26 configured to cause the refrigerant and the heat medium to exchange heat with each other, and a system controller 121a configured to control the heat source-side pump 30. The heat medium circuit 40 includes a load device 70 provided downstream of the heat exchanger 26 and a free bypass pipe 180 that bypasses the load device 70. The heat source-side pump 30 is configured to pump the heat medium to the heat exchanger 26, and the load-side pump 144 is configured to pump the heat medium to the load device 70. The refrigeration cycle system 110 includes a first detecting unit (heat exchanger pressure difference detecting unit 31) provided at the heat medium circuit 40 and configured to detect a pressure difference between pressures at forwardly and backwardly adjacent positions respectively of the heat exchanger 26 in the heat medium circuit, a second detecting unit (pump pressure difference detecting unit 32) provided at a heat medium circuit 40 and configured to detect a pump pressure difference being a pressure difference between pressures at forwardly and backwardly adjacent positions of the heat source-side pump 30 in the heat medium circuit. The system controller 121a obtains pump head (APp(i)) of the heat source-side pump 30 from the pressure difference (heat exchanger pressure difference APhex(i)) detected by the first detecting unit and the rotation speed (for example, operation frequency Fp) of the heat sourceside pump 30, calculates the load-side flow rate of the heat medium flowing in the loadside of the heat medium circuit 40 based on the pressure difference (heat exchanger pressure difference APhex(i)) and the pump head (APp(i)) to obtain the first calculated value (calculated value FA), and calculates the load-side flow rate of the heat medium flowing in the load-side of the heat medium circuit 40 based on a pressure difference detected by the first detecting unit and a pump pressure difference (measured value of pump head APp_a(i)) detected by the second detecting unit to obtain a second calculated value (calculated value FC). The system controller 121a determines the scale depositing status regarding the scale of the heat exchanger 26 by comparing the difference Dfac between the first calculated value and the second calculated value of the load-side flow rate with the difference value stored in advance (difference at initial condition Dfac_0).

[0101] As described above, in the modification of the refrigeration cycle system 110 (see Fig. 6), the depositing status of scales on the heat exchanger 26 is determined by comparing difference Dfac between the first calculated value (calculated value FA) and the second calculated value (calculated value FC) of the load-side flow rate obtained through different methods by using the first detecting unit and the second detecting unit provided at the heat medium circuit 40, with the difference value stored in advance (difference at initial condition Dfac_0). Further, since both the first detecting unit and the second detecting unit are provided at the heat medium circuit 40 in which scales deposit, in the configuration of the present disclosure in which the scale depositing status regarding the scale of the heat exchanger 26 is determined based on difference Dfac between the first calculated value and the second calculated value of the load-side flow rate obtained by using their detection values (heat exchanger pressure difference △Phex(i) and a measured value of pump head APp_a(i)), more accurate determination can be executed in which fluctuation of load and change in operating conditions less affect the determination accuracy compared to conventional configurations in which the depositing status of scales of the heat exchanger is determined based on the temperature difference between the saturation temperature of the refrigerant and the temperature of the heat medium flowing out the heat exchanger. Reference Signs List

[0102] 5 10, 110: refrigeration cycle system, 20: refrigeration cycle apparatus, 21: controller, 21a, 121a: system controller, 22: compressor, 24: heat exchanger, 25: expansion device, 26: heat exchanger, 27: refrigerant circuit, 28: fan, 30: heat sourceside pump, 31: heat exchanger pressure difference detecting unit, 32: pump pressure difference detecting unit, 40, 140: heat medium circuit, 40a, 140a: heat source-side 10 branch pipe, 40b, 140b: load-side branch pipe, 40c, 140c: merger section pipe, 41, 141: forward water-side header pipe, 42a, 142a: first return water-side header pipe, 42b, 142b: second return water-side header pipe, 70: load device, 71: load-side expansion valve, 73: load-side flow rate detector, 80: bypass pipe, 81: bypass valve, 90: bypass pressure difference detecting unit, 99 notification unit, 140d: connecting pipe, 141a: first 15 forward water-side header pipe, 141b: second forward water-side header pipe, 144: load-side pump, 145: forward water-side expansion valve, 180: free bypass pipe.

Claims

1. A refrigeration cycle system including a refrigerant circuit, the refrigerant circuit including a compressor, the compressor being configured to circulate refrigerant in the refrigerant circuit, a heat medium circuit including a heat source-side pump, the heat source-side pump being configured to circulate a heat medium in the heat medium circuit, a heat exchanger configured to cause the refrigerant and the heat medium to exchange heat with each other, and a system controller configured to control the heat source-side pump, the heat medium circuit including a load device provided downstream of the heat exchanger and a bypass pipe bypassing the load device, the refrigeration cycle system comprising:a first detecting unit provided at the heat medium circuit, and configured to detect a pressure difference between forwardly and backwardly adjacent positions of the heat exchanger in the heat medium circuit; anda second detecting unit provided at the heat medium circuit, and configured to detect a bypass pressure difference between forwardly and backwardly adjacent positions of the bypass pipe in the heat medium circuit,wherein the system controller is configured toobtain pump head of the heat source-side pump from the pressure difference detected by the first detecting unit and a rotation speed of the heat sourceside pump, to calculate the bypass pressure difference between the forwardly and backwardly adjacent positions of the bypass pipe in the heat medium circuit based on the pressure difference and the pump head, andcompare a difference between the calculated value of the bypass pressure difference and a measured value of the bypass pressure difference detected by the second detecting unit with a difference value stored in advance to determine a depositing status of scales on the heat exchanger.

2. A refrigeration cycle system including a refrigerant circuit, the refrigerant circuit including a compressor, the compressor being configured to circulate refrigerant in therefrigerant circuit, a heat medium circuit including a heat source-side pump, the heat source-side pump being configured to circulate a heat medium in the heat medium circuit, a heat exchanger configured to cause the refrigerant and the heat medium to exchange heat with each other, and a system controller configured to control the heat source-side pump, the heat medium circuit including a load device provided downstream of the heat exchanger and a bypass pipe bypassing the load device, the refrigeration cycle system comprising:a first detecting unit provided at the heat medium circuit, and configured to detect a pressure difference between forwardly and backwardly adjacent positions of the heat exchanger in the heat medium circuit; anda second detecting unit provided at the heat medium circuit, and configured to detect a pump pressure difference between forwardly and backwardly adjacent positions of the heat source-side pump in the heat medium circuit,wherein the system controller is configured toobtain pump head of the heat source-side pump from the pressure difference detected by the first detecting unit and a rotation speed of the heat source-side pump, to calculate a bypass pressure difference between forwardly and backwardly adjacent positions of the bypass pipe in the heat medium circuit based on the pressure difference and the pump head to obtain a first calculated value,calculate the bypass pressure difference between the forwardly and backwardly adjacent positions of the bypass pipe in the heat medium circuit based on the pressure difference detected by the first detecting unit and the pump pressure difference detected by the second detecting unit to obtain a second calculated value, andcompare a difference between the first calculated value and the second calculated value of the bypass pressure difference with a difference value stored in advance to determine a depositing status of scales on the heat exchanger.

3. A refrigeration cycle system including a refrigerant circuit, the refrigerant circuit including a compressor, the compressor being configured to circulate refrigerant in the refrigerant circuit, a heat medium circuit including a heat source-side pump and a loadside pump, the heat source-side pump and the load-side pump being configured to circulate the heat medium in the heat medium circuit, a heat exchanger configured to cause the refrigerant and the heat medium to exchange heat with each other, and a system controller configured to control the heat source-side pump, the heat medium circuit including a load device provided downstream of the heat exchanger, and a free bypass pipe bypassing the load device, the heat source-side pump being configured to pump the heat medium to the heat exchanger, the load-side pump being configured to pump the heat medium to the load device,the refrigeration cycle system comprising:a first detecting unit provided at the heat medium circuit, and configured to detect a pressure difference between forwardly and backwardly adjacent positions of the heat exchanger in the heat medium circuit; anda second detecting unit provided at a load-side of the heat medium circuit and configured to detect a load-side flow rate of the heat medium,wherein the system controller is configured toobtain pump head of the heat source-side pump from the pressure difference detected by the first detecting unit and a rotation speed of the heat source-side pump,calculate the load-side flow rate of the heat medium flowing on the load-side of the heat medium circuit based on the pressure difference and the pump head, andcompare a difference between the calculated value of the load-side flow rate, and a measured value of the load-side flow rate detected by the second detecting unit with a difference value stored in advance to determine a depositing status of scales on the heat exchanger.

4. A refrigeration cycle system including a refrigerant circuit, the refrigerant circuit including a compressor, the compressor being configured to circulate refrigerant in the refrigerant circuit, a heat medium circuit including a heat source-side pump and a loadside pump, the heat source-side pump and the load-side pump being configured to circulate the heat medium in the heat medium circuit, a heat exchanger being configured to cause the refrigerant and the heat medium to exchange heat with eachother, and a system controller configured to control the heat source-side pump, the heat medium circuit including a load device provided downstream of the heat exchanger, and a free bypass pipe bypassing the load device, the heat source-side pump being configured to pump the heat medium to the heat exchanger, the load-side pump being configured to pump the heat medium to the load device, the refrigeration cycle system comprising:a first detecting unit provided at the heat medium circuit, and configured to detect a pressure difference between forwardly and backwardly adjacent positions of the heat exchanger in the heat medium circuit, anda second detecting unit provided at the heat medium circuit and configured to detect a pump pressure difference between forwardly and backwardly adjacent positions of the heat source-side pump in the heat medium circuit,wherein the system controller is configured toobtain pump head of the heat source-side pump from the pressure difference detected by the first detecting unit and a rotation speed of the heat source-side pump, calculate a load-side flow rate of the heat medium flowing in a load-side of the heat medium circuit based on the pressure difference and the pump head to obtain a first calculated value,calculate the load-side flow rate of the heat medium flowing in the load-side of the heat medium circuit based on the pressure difference detected by the first detecting unit and the pump pressure difference detected by the second detecting unit to obtain the second calculated value, andcompare a difference between the first calculated value and the second calculated value of the load-side flow rate with a difference value stored in advance to determine a depositing status of scales on the heat exchanger.

5. The refrigeration cycle system of any one of claims 1 to 4, wherein the system controller is configured to store the difference calculated at an initial condition in which no scale has deposited on the heat exchanger as the difference value stored in advance.

6. The refrigeration cycle system of any one of claims 1 to 5, further comprising a plurality of refrigeration cycle apparatuses each having the refrigerant circuit, the heat source-side pump and the heat exchanger, wherein5 the heat medium circuit includes a plurality of heat source-side branch pipes toeach of which the heat source-side pump and the heat exchanger of each of the refrigeration cycle apparatuses are provided, and the plurality of heat source-side branch pipes are connected in parallel with each other and connected to the load-side.

7. 10 The refrigeration cycle system of any one of claims 1 to 6, further comprising anotification unit including a display unit or a speaker, wherein the system controller is configured such that when the difference deviates from a difference value stored in advance by equal to or greater than a certain amount, and the system controller is configured to cause the notification unit to issue15 notification that the scales have deposited.INTERNATIONAL SEARCH REPORT International application No. PCT / JP2022 / 038500A. CLASSIFICATION OF SUBJECT MATTER F25B l / 00(2006.01)i;F2SB 49 / 02(2006.01)1 FI: F25B1 / 00 399Y; F25B49 / 02 510F; F25B49 / 02 550 According to International Patent Classification (IPC) or to both national classification and IPC B. FIELDS SEARCHED Minimum documentation searched (classification system followed by classification symbols) F25B1 / 00-49 / 04; F24F5 / 00 Documentation searched other than minimum documentation to the extent that such documents are included in the fields searched Published examined utility model applications of Japan 1922-1996 Published unexamined utility model applications of Japan 1971-2022 Registered utility model specifications of Japan 1996-2022 Published registered utility model applications of Japan 1994-2022 Electronic data base consulted during the international search (name of data base and, where practicable, search terms used) C. DOCUMENTS CONSIDERED TO BE RELEVANT Category* Citation of document, with indication, where appropriate, of the relevant passages Relevant to claim No. A JP 2021-76259 A (DAIKIN IND LTD) 20 May 2021 (2021-05-20) entire text, all drawings 1-7 A JP 2019-52811 A (TAKASAGO THERMAL ENGINEERING) 04 April 2019 (2019-04-04) paragraph [0073], fig. 1 1-7 A WO 2020 / 148887 Al (MITSUBISHI ELECTRIC CORP) 23 July 2020 (2020-07-23) entire text, all drawings 1-7 | | Further documents are listed in the continuation of Box C. | V | See patent family annex. * Special categories of cited documents: “A” document defining the general state of the art which is not considered to be of particular relevance “E” earlier application or patent but published on or after the international filing date “L” document which may throw doubts on priority claim(s) or which is cited to establish the publication date of another citation or other special reason (as specified) “O” document referring to an oral disclosure, use, exhibition or other means “P” document published prior to the international filing date but later than the priority date claimed “T” later document published after the international filing date or priority date and not in conflict with the application but cited to understand the principle or theory underlying the invention “X” document of particular relevance; the claimed invention cannot be considered novel or cannot be considered to involve an inventive step when the document is taken alone “Y” document of particular relevance; the claimed invention cannot be considered to involve an inventive step when the document is combined with one or more other such documents, such combination being obvious to a person skilled in the art document member of the same patent family Date of the actual completion of the international search Date of mailing of the international search report 23 December 2022 10 January 2023 Name and mailing address of the ISA / JP Authorized officer Japan Patent Office (ISA / JP) 3-4-3 Kasumigaseki, Chiyoda-ku, Tokyo 100-8915 Japan Telephone No.INTERNATIONAL SEARCH REPORT Information on patent family members International application No. PCT / JP2022 / 038500Patent document cited in search report Publication date (day / month / year) Patent family member)s) Publication date (day / month / year) JP 2021-76259 A 20 May 2021 US 2022 / 0235945 Al entire text, all drawings EP 4040069 Al CN 114616429 A JP 2019-52811 A 04 April 2019 (Family: none) WO 2020 / 148887 Al 23 July 2020 GB 2595378 A entire text, all drawings

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