Deterioration diagnosis device for water heat exchanger, and deterioration diagnosis method for water heat exchanger

Abstract

A deterioration diagnosis device for a water heat exchanger according to the present embodiment, in which a deterioration pattern determining unit determines that the deterioration pattern of the water heat exchanger is a channel blockage pattern with blockage in a water pipe when a differential pressure flow rate specified by a differential-pressure flow-rate specifying unit is larger than a capacity flow rate specified by a capacity flow-rate specifying unit, and the deterioration pattern determining unit determines that the deterioration pattern of the water heat exchanger is a heat transfer inhibition pattern with inhibited heat transfer in a heat transfer unit when an actual temperature difference specified by an actual temperature difference specifying unit is larger than an estimated temperature difference specified by an estimated temperature difference specifying unit.

Description

Technical Field

[0001] Embodiments of the present invention relate to a deterioration diagnosis device for a water heat exchanger and a deterioration diagnosis method for the water heat exchanger.Background Art

[0002] For example, Patent Literature 1 discloses an abnormality monitoring device for a heat exchanger such as a feedwater heater installed in the condensate and feedwater systems of a power plant, the abnormality monitoring device monitoring both of the differential pressure of a feedwater pressure at the inlet and outlet of the heat exchanger and the heat exchange performance of the heat exchanger, allowing for the determination of not only the presence or absence of scale deposits but also whether the scale has adhered to the inner or outer surface of the heat exchange tube or whether the scale has adhered to feedwater channel parts other than the heat exchange tube.Citation ListPatent Literature

[0003] Patent Literature 1: Japanese Patent No. 2675684Summary of InventionTechnical Problem

[0004] Although the device of Patent Literature 1 can determine the presence of a scale deposit and locate the scale deposit, the device cannot determine the process of deterioration of the heat exchanger, that is, the pattern of the deterioration of the heat exchanger. In particular, in a water heat exchanger for heat exchange between water and a refrigerant, it is assumed that the deterioration patterns include a pattern of deterioration caused by a blocked channel and a pattern of interruption of heat transfer due to a scale. If the pattern of deterioration can be determined, more proper measures can be carried out.

[0005] Therefore, the present embodiment provides a deterioration diagnosis device and a deterioration diagnosis method that can determine the pattern of deterioration of a water heat exchanger for heat exchange between water passing through a water pipe and a refrigerant passing through a refrigerant pipe.Solution to Problem

[0006] A deterioration diagnosis device for a water heat exchanger according to the present embodiment, including: the water heat exchanger including a heat transfer unit between a water pipe that passes water and a refrigerant pipe that passes a refrigerant, the water heat exchanger exchanging, via the heat transfer unit, heat between water passing through the water pipe and the refrigerant passing through the refrigerant pipe; a differential-pressure flow-rate specifying unit that specifies, as a differential pressure flow rate, a flow rate estimated from a pressure difference between a water pressure upstream of the water heat exchanger on the water pipe and a water pressure downstream of the water heat exchanger on the water pipe; a capacity flow-rate specifying unit that estimates a flow rate of water passing through the water pipe based on a capacity of the water heat exchanger and specifies the estimated flow rate as a capacity flow rate; an actual temperature difference specifying unit that specifies, as an actual temperature difference, a temperature difference between a temperature of water passing through the water pipe and a temperature of the refrigerant passing through the refrigerant pipe; an estimated temperature difference specifying unit that estimates, based on the capacity of the water heat exchanger, a temperature difference between the temperature of water passing through the water pipe and the temperature of the refrigerant passing through the refrigerant pipe, and specifies the estimated temperature difference as an estimated temperature difference; and a deterioration pattern determining unit that determines a deterioration pattern of the water heat exchanger based on the differential pressure flow rate specified by the differential-pressure flow-rate specifying unit, the capacity flow rate specified by the capacity flow-rate specifying unit, the actual temperature difference specified by the actual temperature difference specifying unit, and the estimated temperature difference specified by the estimated temperature difference specifying unit, wherein the deterioration pattern determining unit determines that the deterioration pattern of the water heat exchanger is a channel blockage pattern with blockage in the water pipe when the differential pressure flow rate specified by the differential-pressure flow-rate specifying unit is larger than the capacity flow rate specified by the capacity flow-rate specifying unit, and the deterioration pattern determining unit determines that the deterioration pattern of the water heat exchanger is a heat transfer inhibition pattern with inhibited heat transfer in the heat transfer unit when the actual temperature difference specified by the actual temperature difference specifying unit is larger than the estimated temperature difference specified by the estimated temperature difference specifying unit.

[0007] A deterioration diagnosis method for a water heat exchanger according to the present embodiment, including a heat transfer unit between a water pipe that passes water and a refrigerant pipe that passes a refrigerant, the water heat exchanger exchanging, via the heat transfer unit, heat between water passing through the water pipe and the refrigerant passing through the refrigerant pipe, the deterioration diagnosis method including: differential-pressure flow-rate specifying processing that specifies, as a differential pressure flow rate, a flow rate estimated from a pressure difference between a water pressure upstream of the water heat exchanger on the water pipe and a water pressure downstream of the water heat exchanger on the water pipe; capacity flow-rate specifying processing that estimates a flow rate of water passing through the water pipe based on a capacity of the water heat exchanger and specifies the estimated flow rate as a capacity flow rate; actual temperature difference specifying processing that specifies, as an actual temperature difference, a temperature difference between a temperature of water passing through the water pipe and a temperature of the refrigerant passing through the refrigerant pipe; estimated temperature difference specifying processing that estimates, based on the capacity of the water heat exchanger, a temperature difference between the temperature of water passing through the water pipe and the temperature of the refrigerant passing through the refrigerant pipe, and specifies the estimated temperature difference as an estimated temperature difference; and deterioration pattern determining processing that determines a deterioration pattern of the water heat exchanger based on the differential pressure flow rate specified by the differential-pressure flow-rate specifying processing, the capacity flow rate specified by the capacity flow-rate specifying processing, the actual temperature difference specified by the actual temperature difference specifying processing, and the estimated temperature difference specified by the estimated temperature difference specifying processing, wherein the deterioration pattern determining processing determines that the deterioration pattern of the water heat exchanger is a channel blockage pattern with blockage in the water pipe when the differential pressure flow rate specified by the differential-pressure flow-rate specifying processing is larger than the capacity flow rate specified by the capacity flow-rate specifying processing, and the deterioration pattern determining processing determines that the deterioration pattern of the water heat exchanger is a heat transfer inhibition pattern with inhibited heat transfer in the heat transfer unit when the actual temperature difference specified by the actual temperature difference specifying processing is larger than the estimated temperature difference specified by the estimated temperature difference specifying processing.Brief Description of Drawings

[0008] [Figure 1] Figure 1 is a schematic diagram showing a configuration example of a chiller system according to a first embodiment. [Figure 2] Figure 2 is a schematic block diagram showing a configuration example of a control device according to the first embodiment. [Figure 3] Figure 3 is a schematic block diagram showing a configuration example of a control device according to a second embodiment. [Figure 4] Figure 4 is a schematic diagram showing a configuration example of a chiller system according to the second embodiment. [Figure 5] Figure 5 is a schematic diagram showing a configuration example of a chiller system according to a third embodiment. [Figure 6] Figure 6 is a schematic diagram showing a configuration example of a chiller system according to a fourth embodiment. Description of Embodiments

[0009] Hereinafter, embodiments relating to a deterioration diagnosis device and a deterioration diagnosis method for a water heat exchanger will be described with reference to the accompanying drawings. In the embodiments, substantially the same elements are indicated by the same reference numerals, and the explanation thereof is omitted.(First Embodiment)

[0010] A chiller system 100 shown in Figure 1 includes a refrigeration cycle unit 200 and a use-side unit 300. The chiller system 100 exchanges heat between a refrigerant passing through the refrigeration cycle unit 200 and water passing through the use-side unit 300, enabling cooling and heating of an object and a space that are to be subjected to temperature control by the chiller system 100.

[0011] The refrigeration cycle unit 200 includes a compressor 201, an air heat exchanger 202, a fan 203, an expansion valve 204, a water heat exchanger 205, an accumulator 206, a four-way valve 207, and a refrigerant pipe 208. The compressor 201, the air heat exchanger 202, the expansion valve 204, the water heat exchanger 205, the accumulator 206, and the four-way valve 207 are sequentially connected via the refrigerant pipe 208.

[0012] The compressor 201 is configured to compress the refrigerant. For example, the compressor 201 can change the operation frequency under known inverter control. The compressor 201 may be configured with an unchangeable operation frequency, that is, a fixed operation frequency.

[0013] The air heat exchanger 202 is, for example, a fin-and-tube heat exchanger. That is, the air heat exchanger 202 is a heat exchanger configured with the refrigerant pipe 208 inserted into a plurality of flat fins. The fan 203 is disposed near the air heat exchanger 202. The air heat exchanger 202 exchanges heat between air fed from the fan 203 and the refrigerant passing through the air heat exchanger 202.

[0014] The expansion valve 204 is configured to regulate the valve position. The expansion valve 204 includes, for example, a valve body having a through hole, a needle that can be moved into and out of the through hole, and a power source that moves the needle forward and backward. When the through hole is closed by the needle, the expansion valve 204 interrupts the passage of the refrigerant in the refrigeration cycle unit 200. At this time, the expansion valve 204 is in a closed state, and the expansion valve 204 has the minimum opening. When the needle is farthest from the through hole, the amount of refrigerant flowing through the refrigeration cycle unit 200 is maximized. At this time, the expansion valve 204 has the maximum opening.

[0015] The water heat exchanger 205 exchanges heat between water passing through a water pipe 301 to be heated or cooled and the refrigerant passing through the refrigerant pipe 208. A pump 302 pumps water in the water pipe 301 into the water heat exchanger 205.

[0016] The water heat exchanger 205 is a so-called plate type water heat exchanger. The water heat exchanger 205 is configured such that a plurality of stacked heat exchanging plates are held by a pair of cover plates in the stacking direction. At least one of the cover plates has a plurality of couplings that act as an inlet and an outlet of water and the refrigerant. The water heat exchanger 205 includes a heat transfer unit 205a connected to the water pipe 301 that passes water and the refrigerant pipe 208 that passes the refrigerant, the heat transfer unit 205a including water channels and refrigerant channels alternately separated by plates, allowing heat exchange between water and the refrigerant.

[0017] For example, the accumulator 206 has a metallic case such as a steel case. A refrigerant in a liquid phase is stored in the lower part of the accumulator 206. A refrigerant in a gaseous phase is stored in the upper part of the accumulator 206. The accumulator 206 supplies the gaseous-phase refrigerant to the compressor 201.

[0018] The four-way valve 207 switches the refrigeration cycle unit 200 between a heating operation state and a cooling operation state by switching the flowing directions of the refrigerant in the refrigerant pipe 208. Between the heating operation state and the cooling operation state, the flowing direction of the refrigerant is switched to the opposite direction in the refrigerant pipe 208.

[0019] When the refrigeration cycle unit 200 is switched to the heating operation state, water passing through the water pipe 301 is heated by the water heat exchanger 205. In the heating operation state, the refrigerant passes through the compressor 201, the water heat exchanger 205, the expansion valve 204, the air heat exchanger 202, and the accumulator 206 in this order.

[0020] More specifically, the refrigerant heated by the compressor 201 is condensed in the water heat exchanger 205 and exchanges heat with water in the water pipe 301. Thus, water passing through the water pipe 301 is heated. At this time, the water heat exchanger 205 acts as a condenser for condensing the refrigerant. The refrigerant having exchanged heat with water in the water heat exchanger 205 is decompressed in the expansion valve 204 and then further exchanges heat with air, which is fed from the fan 203, in the air heat exchanger 202. At this time, the air heat exchanger 202 acts as an evaporator for evaporating the refrigerant. The refrigerant having exchanged heat with air in the air heat exchanger 202 is returned to the compressor 201 through the accumulator 206, is heated again, and then is transferred to the water heat exchanger 205. The circulation of the refrigerant allows the water heat exchanger 205 to heat water passing through the water pipe 301.

[0021] When the refrigeration cycle unit 200 is switched to the cooling operation state, water passing through the water pipe 301 is cooled by the water heat exchanger 205. In the cooling operation state, the refrigerant passes through the compressor 201, the air heat exchanger 202, the expansion valve 204, the water heat exchanger 205, and the accumulator 206 in this order.

[0022] More specifically, the refrigerant heated by the compressor 201 is condensed in the air heat exchanger 202 and exchanges heat with air fed from the fan 203. At this time, the air heat exchanger 202 acts as a condenser for condensing the refrigerant. The refrigerant having exchanged heat with air in the air heat exchanger 202 is decompressed in the expansion valve 204 and then further exchanges heat with water, which passes through the water pipe 301, in the water heat exchanger 205. Thus, water passing through the water pipe 301 is cooled. At this time, the water heat exchanger 205 acts as an evaporator for evaporating the refrigerant. The refrigerant having exchanged heat with air in the water heat exchanger 205 is returned to the compressor 201 through the accumulator 206, is heated again, and then is transferred to the air heat exchanger 202. The circulation of the refrigerant allows the water heat exchanger 205 to cool water passing through the water pipe 301.

[0023] The chiller system 100 includes an accumulator-side refrigerant pressure gauge 221 and an accumulator-side refrigerant thermometer 231 at portions closer to the accumulator 206 than the compressor 201 on the refrigerant pipe 208. In addition, the chiller system 100 includes an opposite accumulator-side refrigerant pressure gauge 222 and an opposite accumulator-side refrigerant thermometer 232 at portions on the opposite side of the compressor 201 from the accumulator 206 on the refrigerant pipe 208.

[0024] The chiller system 100 includes an upstream-side water pressure gauge 321 and an upstream-side water temperature gauge 331 at portions upstream of the water heat exchanger 205 on the water pipe 301. Furthermore, the chiller system 100 includes a downstream-side water pressure gauge 322 and a downstream-side water temperature gauge 332 at portions downstream of the water heat exchanger 205 on the water pipe 301.

[0025] A control device 400 for controlling the chiller system 100 will be specifically described below. For example, the control device 400 is mainly composed of a computer and can control the overall operation of the chiller system 100 based on a control program and various kinds of setting data. In addition, the control device 400 functions as an example of a deterioration diagnosis device for the water heat exchanger 205 and is configured to diagnose deterioration of the water heat exchanger 205.

[0026] Various driving-system components such as the compressor 201, the fan 203, the expansion valve 204, the four-way valve 207, and the pump 302 are connected to the control device 400. In addition, various sensor-system components such as the accumulator-side refrigerant pressure gauge 221, the accumulator-side refrigerant thermometer 231, the opposite accumulator-side refrigerant pressure gauge 222, the opposite accumulator-side refrigerant thermometer 232, the upstream-side water pressure gauge 321, the upstream-side water temperature gauge 331, the downstream-side water pressure gauge 322, and the downstream-side water temperature gauge 332 are connected to the control device 400.

[0027] As shown in Figure 2, by implementing a deterioration diagnosis program, the control device 400 virtually implements a differential-pressure flow-rate specifying processing unit 401, a capacity-flow-rate specifying processing unit 402, an actual-temperature-difference specifying processing unit 403, an estimated-temperature-difference specifying processing unit 404, a deterioration pattern determining processing unit 405, and a notification processing unit 406 by software. In addition, the differential-pressure flow-rate specifying processing unit 401, the capacity-flow-rate specifying processing unit 402, the actual-temperature-difference specifying processing unit 403, the estimated-temperature-difference specifying processing unit 404, the deterioration pattern determining processing unit 405, and the notification processing unit 406 may be implemented by hardware or a combination of software and hardware.

[0028] The differential-pressure flow-rate specifying processing unit 401 is an example of a differential-pressure flow-rate specifying unit and can perform differential-pressure flow-rate specifying processing. The differential-pressure flow-rate specifying processing is processing for specifying, as a differential pressure flow rate, a flow rate estimated from a pressure difference between a water pressure detected by the upstream-side water pressure gauge 321 at a portion upstream of the water heat exchanger 205 on the water pipe 301 and a water pressure detected by the downstream-side water pressure gauge 322 at a portion downstream of the water heat exchanger 205 on the water pipe 301. In other words, it can be estimated that the flow rate of water increases with a pressure difference between a water pressure upstream of the water heat exchanger 205 and a water pressure downstream of the water heat exchanger 205, whereas the flow rate of water decreases with a reduction in pressure difference.

[0029] The capacity-flow-rate specifying processing unit 402 is an example of a capacity flow-rate specifying unit and can perform capacity flow-rate specifying processing. The capacity flow-rate specifying processing is processing for estimating the flow rate of water passing through the water pipe 301 based on the capacity of the water heat exchanger 205 and specifying the estimated flow rate as a capacity flow rate.

[0030] The capacity of the water heat exchanger 205 can be estimated based on the enthalpy change of the refrigerant passing through the refrigerant pipe 208 or the circulation amount or the like of the refrigerant in the refrigerant pipe 208. The enthalpy change of the refrigerant passing through the refrigerant pipe 208 can be calculated based on the pressure of the refrigerant passing through the refrigerant pipe 208 or the temperature of the refrigerant passing through the refrigerant pipe 208. The pressure of the refrigerant is detected by the accumulator-side refrigerant pressure gauge 221 or the opposite accumulator-side refrigerant pressure gauge 222, and the temperature of the refrigerant is detected by the accumulator-side refrigerant thermometer 231 or the opposite accumulator-side refrigerant thermometer 232. The circulation amount of the refrigerant in the refrigerant pipe 208 can be calculated based on the driving frequency of the compressor 201 or the density of the refrigerant contained in the refrigerant pipe 208. The density of the refrigerant contained in the refrigerant pipe 208 varies depending on the kind of refrigerant and may be changed by the influence of the amount of the contained refrigerant or the ambient temperature or the like.

[0031] Furthermore, the capacity of the water heat exchanger 205 can be estimated with higher accuracy by reflecting a temperature change of water passing through the water pipe 301, the water temperature being detected by the upstream-side water temperature gauge 331 and the downstream-side water temperature gauge 332.

[0032] The actual-temperature-difference specifying processing unit 403 is an example of an actual temperature difference specifying unit and can perform actual temperature difference specifying processing. The actual temperature difference specifying processing is processing for specifying, as an actual temperature difference, the temperature difference between the temperature of water passing through the water pipe 301 and the temperature of the refrigerant passing through the refrigerant pipe 208 in the water heat exchanger 205. That is, the actual temperature difference can be defined as a temperature difference between water and the refrigerant in the water heat exchanger 205. The temperature of water passing through the water pipe 301 in the water heat exchanger 205 can be detected by the upstream-side water temperature gauge 331 and the downstream-side water temperature gauge 332. The temperature of the refrigerant passing through the refrigerant pipe 208 can be detected by the accumulator-side refrigerant thermometer 231 and the opposite accumulator-side refrigerant thermometer 232.

[0033] The estimated-temperature-difference specifying processing unit 404 is an example of an estimated temperature difference specifying unit and can perform estimated temperature difference specifying processing. The estimated temperature difference specifying processing is processing for estimating, based on the capacity of the water heat exchanger 205, the temperature difference between the temperature of water passing through the water pipe 301 and the temperature of the refrigerant passing through the refrigerant pipe 208 in the water heat exchanger 205, and specifying the estimated temperature difference as an estimated temperature difference.

[0034] As described above, the capacity of the water heat exchanger 205 can be estimated based on the enthalpy change of the refrigerant passing through the refrigerant pipe 208 or the circulation amount or the like of the refrigerant in the refrigerant pipe 208. In addition, the capacity can be estimated with higher accuracy by reflecting a temperature change of water passing through the water pipe 301.

[0035] The deterioration pattern determining processing unit 405 is an example of a deterioration pattern determining unit and can perform deterioration pattern determining processing. The deterioration pattern determining processing is processing for determining the deterioration pattern of the water heat exchanger 205 based on the differential pressure flow rate specified by the differential-pressure flow-rate specifying processing unit 401, the capacity flow rate specified by the capacity-flow-rate specifying processing unit 402, the actual temperature difference specified by the actual-temperature-difference specifying processing unit 403, and the estimated temperature difference specified by the estimated-temperature-difference specifying processing unit 404.

[0036] More specifically, when the differential pressure flow rate specified by the differential-pressure flow-rate specifying processing unit 401 is larger than the capacity flow rate specified by the capacity-flow-rate specifying processing unit 402 by a predetermined reference amount or more, the deterioration pattern determining processing unit 405 determines that the deterioration pattern of the water heat exchanger 205 is "channel blockage pattern". The channel blockage pattern is a deterioration pattern in which scale deposited in the water pipe 301 blocks the water pipe 301. The predetermined reference amount for determining the presence or absence of "channel blockage pattern" can be changed and set as appropriate.

[0037] Furthermore, the deterioration pattern determining processing unit 405 determines that the deterioration pattern of the water heat exchanger 205 is "heat transfer inhibition pattern" when the actual temperature difference specified by the actual-temperature-difference specifying processing unit 403 is larger than the estimated temperature difference specified by the estimated-temperature-difference specifying processing unit 404 by the predetermined reference amount or more. The heat transfer inhibition pattern is a deterioration pattern in which scale deposited on the heat transfer unit 205a inhibits the heat transfer of the heat transfer unit 205a. The predetermined reference amount for determining the presence or absence of "heat transfer inhibition pattern" can be changed and set as appropriate.

[0038] In the water heat exchanger 205, only deterioration in "channel blockage pattern" may occur, only deterioration in "heat transfer inhibition pattern" may occur, or deterioration in both "channel blockage pattern" and "heat transfer inhibition pattern" may occur.

[0039] The notification processing unit 406 is an example of a notification unit and can perform notification processing. The notification processing is processing for notification of the determination result of a deterioration pattern determined by the deterioration pattern determining processing unit 405. In the notification processing, for example, notification may be provided as visual information through a display output device (not shown) provided for the control device 400, may be provided as auditory information through a speech output device (not shown) provided for the control device 400, or may be provided as visual information and auditory information. The display output device is, for example, a display. The speech output device is, for example, a speaker.

[0040] When the determination result of the deterioration pattern determined by the deterioration pattern determining processing unit 405 is "channel blockage pattern", the notification processing unit 406 notifies the water heat exchanger 205 of the occurrence of deterioration in "channel blockage pattern". When the determination result of the deterioration pattern determined by the deterioration pattern determining processing unit 405 is "heat transfer inhibition pattern", the notification processing unit 406 notifies the water heat exchanger 205 of the occurrence of deterioration in "heat transfer inhibition pattern".

[0041] When the determination result of the deterioration pattern determined by the deterioration pattern determining processing unit 405 is "channel blockage pattern" and "heat transfer inhibition pattern", the notification processing unit 406 may notify the water heat exchanger 205 of the occurrence of deterioration in "channel blockage pattern" and deterioration in "heat transfer inhibition pattern" or only one of the deterioration patterns. When notification of only one of the deterioration patterns is provided, for example, a deterioration pattern at a higher degree of deterioration may be selected for notification, or a user-specified deterioration pattern may be selected for notification.

[0042] According to the control device 400 of the chiller system 100 described above, based on the magnitude relationship between the differential pressure flow rate specified by the differential-pressure flow-rate specifying processing unit 401 and the capacity flow rate specified by the capacity-flow-rate specifying processing unit 402 and the magnitude relationship between the actual temperature difference specified by the actual-temperature-difference specifying processing unit 403 and the estimated temperature difference specified by the estimated-temperature-difference specifying processing unit 404, it is possible to determine whether the deterioration pattern of the water heat exchanger 205 is "channel blockage pattern" or "heat transfer inhibition pattern". In the water heat exchanger 205, deterioration may occur in both "channel blockage pattern" and "heat transfer inhibition pattern" at the same time. In such a case, it is possible to determine that deterioration patterns of "channel blockage pattern" and "heat transfer inhibition pattern" occur at the same time. Therefore, a deterioration pattern can be determined for the water heat exchanger 205 for heat exchange between water passing through the water pipe 301 and the refrigerant passing through the refrigerant pipe 208, and thus more proper measures can be carried out according to the deterioration pattern occurring in the water heat exchanger 205.

[0043] In any one of the two patterns of "channel blockage pattern" and "heat transfer inhibition pattern", the channel in the water pipe 301 is blocked in the end. However, in the early stage, that is, at the beginning of the blockage of the channel, differences in the deterioration patterns are recognized as follows: In "channel blockage pattern", the pressure loss of water passing through the water pipe 301 increases significantly, whereas in "heat transfer inhibition pattern", the heat transfer capability of the heat transfer unit 205a deteriorates significantly.

[0044] Thus, according to a comparison in the magnitude relationship between the differential pressure flow rate specified by the differential-pressure flow-rate specifying processing unit 401 and the capacity flow rate specified by the capacity-flow-rate specifying processing unit 402, it is possible to determine whether or not "channel blockage pattern" has occurred. Specifically, when scale clogs the water pipe 301, the pressure loss of water passing through the water pipe 301 increases. When the pressure loss of water passing through the water pipe 301 increases, the differential pressure flow rate specified by the differential-pressure flow-rate specifying processing unit 401 is likely to increase due to the influence of the increase in pressure loss, whereas the capacity flow rate specified by the capacity-flow-rate specifying processing unit 402 is less affected by the increase in pressure loss and thus is less likely to change because the capacity flow rate is based on the capacity of the water heat exchanger 205. Therefore, when the differential pressure flow rate specified by the differential-pressure flow-rate specifying processing unit 401 is sufficiently larger than the capacity flow rate specified by the capacity-flow-rate specifying processing unit 402, the deterioration pattern of the water heat exchanger 205 can be determined as "channel blockage pattern".

[0045] Furthermore, according to a comparison in the magnitude relationship between the actual temperature difference specified by the actual-temperature-difference specifying processing unit 403 and the estimated temperature difference specified by the estimated-temperature-difference specifying processing unit 404, it is possible to whether or not "heat transfer inhibition pattern" has occurred. That is, scale deposited on the heat transfer unit 205a deteriorates the heat transfer capability of the heat transfer unit 205a. When the heat transfer capability of the heat transfer unit 205a deteriorates, the actual temperature difference specified by the actual-temperature-difference specifying processing unit 403 is likely to increase due to the influence of the deterioration of the heat transfer capability, whereas the estimated temperature difference specified by the estimated-temperature-difference specifying processing unit 404 is less affected by the deterioration of the heat transfer capability and thus is less likely to change because the estimated temperature difference is based on the capacity of the water heat exchanger 205. Therefore, when the actual temperature difference specified by the actual-temperature-difference specifying processing unit 403 is sufficiently larger than the estimated temperature difference specified by the estimated-temperature-difference specifying processing unit 404, the deterioration pattern of the water heat exchanger 205 can be determined as "heat transfer inhibition pattern".

[0046] As described above, the present application discloses the embodiment that focuses on the significant differences in deterioration patterns recognized in the initial stage of channel blockage, enabling the determination of the deterioration pattern of the water heat exchanger 205.(Second Embodiment)

[0047] A control device 400 shown in Figure 3 includes an actual-flow-rate specifying processing unit 407 instead of a capacity-flow-rate specifying processing unit 402. The control device 400 virtually implements the actual-flow-rate specifying processing unit 407 by software by executing a deterioration diagnosis program. The actual-flow-rate specifying processing unit 407 may be implemented by hardware or a combination of software and hardware.

[0048] The actual-flow-rate specifying processing unit 407 is an example of an actual flow-rate specifying unit and can perform actual flow-rate specifying processing. The actual flow-rate specifying processing is processing for specifying, as an actual flow rate, the flow rate of water actually passing through a water pipe 301. The flow rate of water actually passing through the water pipe 301 can be detected by a flowmeter 341 shown in Figure 4. In this case, on a water pipe 301, the flowmeter 341 is provided at a portion upstream of a water heat exchanger 205. For example, the flowmeter 341 may be provided at a portion downstream of the water heat exchanger 205 on the water pipe 301 or may be provided at a portion in the water heat exchanger 205 on the water pipe 301 as long as the flowmeter 341 can detect the flow rate of water actually passing through the water pipe 301.

[0049] When the differential pressure flow rate specified by a differential-pressure flow-rate specifying processing unit 401 is larger than the actual flow rate specified by the actual-flow-rate specifying processing unit 407 by a predetermined reference amount or more, a deterioration pattern determining processing unit 405 determines that the deterioration pattern of the water heat exchanger 205 is "channel blockage pattern".

[0050] Also in a second embodiment, a deterioration pattern can be determined for the water heat exchanger 205 for heat exchange between water passing through the water pipe 301 and a refrigerant passing through a refrigerant pipe 208.

[0051] Furthermore, a differential pressure flow rate specified by the differential-pressure flow-rate specifying processing unit 401 can be compared with an actual measured value instead of an estimated value, enabling further accurate determination of whether or not "channel blockage pattern" has occurred.

[0052] In the second embodiment, the control device 400 includes the actual-flow-rate specifying processing unit 407 as well as the capacity-flow-rate specifying processing unit 402 and may select, as appropriate, the flow rate value of one of the capacity flow rate specified by the capacity-flow-rate specifying processing unit 402 and the actual flow rate specified by the actual-flow-rate specifying processing unit 407 and compare the flow rate value with the differential pressure flow rate specified by the differential-pressure flow-rate specifying processing unit 401. Alternatively, for example, the mean value, the median value, the maximum value, and the minimum value may be specified for the capacity flow rate specified by the capacity-flow-rate specifying processing unit 402 and the actual flow rate specified by the actual-flow-rate specifying processing unit 407, and the specified value may be compared with the differential pressure flow rate specified by the differential-pressure flow-rate specifying processing unit 401.(Third Embodiment)

[0053] A chiller system 100 shown in Figure 5 includes a plurality of refrigeration cycle units 200, in this case, the two refrigeration cycle units 200 for a use-side unit 300. In other words, a plurality of refrigerant pipes 208, in this case, the two refrigerant pipes 208 are associated with a water pipe 301.

[0054] In this configuration example, a deterioration pattern determining processing unit 405 can determine a deterioration pattern by using the capacity of a water heat exchanger 205, the capacity being estimated in the relationship between one of the refrigerant pipes 208 and the water pipe 301, and the deterioration pattern determining processing unit 405 can also determine a deterioration pattern by using the capacity of the water heat exchanger 205, the capacity being estimated in the relationship between the other refrigerant pipe 208 and the water pipe 301.

[0055] When a deterioration pattern is determined by using the capacity of the water heat exchanger 205, the capacity being estimated in the relationship between one of the refrigerant pipes 208 and the water pipe 301, a notification processing unit 406 can provide notification on the occurrence of deterioration in relation to one of the refrigerant pipes 208. When a deterioration pattern is determined by using the capacity of the water heat exchanger 205, the capacity being estimated in the relationship between the other refrigerant pipe 208 and the water pipe 301, the notification processing unit 406 can provide notification on the occurrence of deterioration in relation to the other refrigerant pipe 208. In other words, according to this configuration example, which one of the plurality of refrigerant pipes 208 relates to a deterioration of the water heat exchanger 205 can be identified, and which one of the plurality of refrigeration cycle units 200 relates to a deterioration of the water heat exchanger 205 can be identified.

[0056] Even if a deterioration pattern is determined by using the capacity of the water heat exchanger 205, the capacity being estimated in the relationship between one of the plurality of refrigerant pipes 208 and the water pipe 301, the notification processing unit 406 may provide notification on the occurrence of deterioration in the water heat exchanger 205 in relation to the overall refrigerant pipes 208 including the other refrigerant pipe 208.(Fourth Embodiment)

[0057] A chiller system 100 shown in Figure 6 includes a plurality of water heat exchangers 205, in this case, the two water heat exchangers 205 connected in series on a water pipe 301. On the water pipe 301, an intermediate water pressure gauge 323 and an intermediate water temperature gauge 333 are provided at portions between the plurality of water heat exchangers 205. In other words, in the configuration example of a fourth embodiment, the components shown in the first embodiment, in this case, two of the components are connected in series. According to the configuration example, a deterioration pattern determining processing unit 405 can determine a deterioration pattern for each of the water heat exchangers 205.

[0058] When a deterioration pattern is determined for one of the water heat exchangers 205, a notification processing unit 406 can provide notification on the occurrence of deterioration in one of the water heat exchangers 205. When a deterioration pattern is determined for the other water heat exchanger 205, the notification processing unit 406 can provide notification on the occurrence of deterioration in the other water heat exchanger 205. In other words, according to this configuration example, which one of the water heat exchangers 205 has deteriorated can be identified.

[0059] Furthermore, even if a deterioration pattern is determined for one of the plurality of water heat exchangers 205, the notification processing unit 406 may provide notification on the occurrence of deterioration in the overall water heat exchangers 205 including the other water heat exchanger 205.(Other Embodiments)

[0060] The present embodiment is not limited to the foregoing embodiments and can be changed or extended in various ways within the scope of the invention. For example, at least two or more of the embodiments may be combined as appropriate. Furthermore, a differential pressure flow rate, a capacity flow rate, an actual temperature difference, and an estimated temperature difference can be specified using various known techniques as well as the foregoing technique.

[0061] While the embodiments of the present invention have been described, these embodiments have been presented by way of example only and are not intended to limit the scope of the invention. These novel embodiments can be embodied in a variety of other forms, and various omissions, substitutions, and changes can be made without departing from the spirit of the invention. The present embodiment and modifications thereof are included in the scope and spirit of the invention and are included in the scope of the claimed invention and their equivalents.Reference Signs List

[0062] In the drawings, 205 denotes a water heat exchanger, 205a denotes a heat transfer unit, 208 denotes a refrigerant pipe, 301 denotes a water pipe, 400 denotes a control device (a deterioration diagnosis device for a water heat exchanger), 401 denotes a differential-pressure flow-rate specifying processing unit (differential-pressure flow-rate specifying unit), 402 denotes a capacity-flow-rate specifying processing unit (capacity flow-rate specifying unit), 403 denotes an actual-temperature-difference specifying processing unit (actual temperature difference specifying unit), 404 denotes an estimated-temperature-difference specifying processing unit (estimated temperature difference specifying unit), 405 denotes a deterioration pattern determining processing unit (deterioration pattern determining unit), and 407 denotes an actual-flow-rate specifying processing unit (actual flow-rate specifying unit).

Claims

1. A deterioration diagnosis device for a water heat exchanger, comprising: the water heat exchanger including a heat transfer unit between a water pipe that passes water and a refrigerant pipe that passes a refrigerant, the water heat exchanger exchanging, via the heat transfer unit, heat between water passing through the water pipe and the refrigerant passing through the refrigerant pipe; a differential-pressure flow-rate specifying unit that specifies, as a differential pressure flow rate, a flow rate estimated from a pressure difference between a water pressure upstream of the water heat exchanger on the water pipe and a water pressure downstream of the water heat exchanger on the water pipe; a capacity flow-rate specifying unit that estimates a flow rate of water passing through the water pipe based on a capacity of the water heat exchanger and specifies the estimated flow rate as a capacity flow rate; an actual temperature difference specifying unit that specifies, as an actual temperature difference, a temperature difference between a temperature of water passing through the water pipe and a temperature of the refrigerant passing through the refrigerant pipe; an estimated temperature difference specifying unit that estimates, based on the capacity of the water heat exchanger, a temperature difference between the temperature of water passing through the water pipe and the temperature of the refrigerant passing through the refrigerant pipe, and specifies the estimated temperature difference as an estimated temperature difference; and a deterioration pattern determining unit that determines a deterioration pattern of the water heat exchanger based on the differential pressure flow rate specified by the differential-pressure flow-rate specifying unit, the capacity flow rate specified by the capacity flow-rate specifying unit, the actual temperature difference specified by the actual temperature difference specifying unit, and the estimated temperature difference specified by the estimated temperature difference specifying unit, wherein the deterioration pattern determining unit determines that the deterioration pattern of the water heat exchanger is a channel blockage pattern with blockage in the water pipe when the differential pressure flow rate specified by the differential-pressure flow-rate specifying unit is larger than the capacity flow rate specified by the capacity flow-rate specifying unit, and the deterioration pattern determining unit determines that the deterioration pattern of the water heat exchanger is a heat transfer inhibition pattern with inhibited heat transfer in the heat transfer unit when the actual temperature difference specified by the actual temperature difference specifying unit is larger than the estimated temperature difference specified by the estimated temperature difference specifying unit.

2. The deterioration diagnosis device for a water heat exchanger according to claim 1, further comprising an actual flow-rate specifying unit that specifies, as an actual flow rate, a flow rate of water actually passing through the water pipe, wherein the deterioration pattern determining unit determines that the deterioration pattern of the water heat exchanger is the channel blockage pattern when the differential pressure flow rate specified by the differential-pressure flow-rate specifying unit is larger than the actual flow rate specified by the actual flow-rate specifying unit.

3. A deterioration diagnosis method for a water heat exchanger including a heat transfer unit between a water pipe that passes water and a refrigerant pipe that passes a refrigerant, the water heat exchanger exchanging, via the heat transfer unit, heat between water passing through the water pipe and the refrigerant passing through the refrigerant pipe, the deterioration diagnosis method comprising: differential-pressure flow-rate specifying processing that specifies, as a differential pressure flow rate, a flow rate estimated from a pressure difference between a water pressure upstream of the water heat exchanger on the water pipe and a water pressure downstream of the water heat exchanger on the water pipe; capacity flow-rate specifying processing that estimates a flow rate of water passing through the water pipe based on a capacity of the water heat exchanger and specifies the estimated flow rate as a capacity flow rate; actual temperature difference specifying processing that specifies, as an actual temperature difference, a temperature difference between a temperature of water passing through the water pipe and a temperature of the refrigerant passing through the refrigerant pipe; estimated temperature difference specifying processing that estimates, based on the capacity of the water heat exchanger, a temperature difference between the temperature of water passing through the water pipe and the temperature of the refrigerant passing through the refrigerant pipe, and specifies the estimated temperature difference as an estimated temperature difference; and deterioration pattern determining processing that determines a deterioration pattern of the water heat exchanger based on the differential pressure flow rate specified by the differential-pressure flow-rate specifying processing, the capacity flow rate specified by the capacity flow-rate specifying processing, the actual temperature difference specified by the actual temperature difference specifying processing, and the estimated temperature difference specified by the estimated temperature difference specifying processing, wherein the deterioration pattern determining processing determines that the deterioration pattern of the water heat exchanger is a channel blockage pattern with blockage in the water pipe when the differential pressure flow rate specified by the differential-pressure flow-rate specifying processing is larger than the capacity flow rate specified by the capacity flow-rate specifying processing, and the deterioration pattern determining processing determines that the deterioration pattern of the water heat exchanger is a heat transfer inhibition pattern with inhibited heat transfer in the heat transfer unit when the actual temperature difference specified by the actual temperature difference specifying processing is larger than the estimated temperature difference specified by the estimated temperature difference specifying processing.

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