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

Abstract

According to a deterioration diagnosis device for a water heat exchanger according to the present embodiment, when a differential pressure flow rate specified by a differential pressure flow rate specifying unit is greater than a capacity flow rate specified by a capacity flow rate specifying unit, a deterioration pattern determining unit determines that a deterioration pattern of the water heat exchanger is a flow path closing pattern in which the inside of a water pipe is closed, and, when an actual temperature difference specified by an actual temperature difference specifying unit is greater than an estimated temperature difference specified by an estimated temperature difference specifying unit, the deterioration pattern determining unit determines that the deterioration pattern of the water heat exchanger is a heat transfer inhibition pattern in which heat transfer of a heat transfer unit is inhibited.

Description

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

[0001] An embodiment of the present invention relates to a deterioration diagnosis device and a deterioration diagnosis method for a water heat exchanger.

[0002] For example, Patent Document 1 discloses an abnormality monitoring device for a heat exchanger that monitors both the differential pressure of the water supply pressure at the inlet and outlet of a heat exchanger and the heat exchange performance of the heat exchanger in a heat exchanger such as a feedwater heater installed in the condensate or feedwater system of a power plant, thereby making it possible to determine not only whether scale has adhered, but also whether the scale has adhered to the inner or outer surface of the heat exchange tube, or to a part of the water supply flow path other than the heat exchange tube.

[0003] Patent No. 2675684

[0004] However, while the device of Patent Document 1 can identify the presence of scale and the location of the scale, it cannot determine how the heat exchanger has deteriorated, that is, the deterioration pattern of the heat exchanger. In particular, in a water heat exchanger that exchanges heat between water and a refrigerant, possible deterioration patterns include deterioration due to blockage of the flow path and deterioration due to inhibition of heat transfer by scale. If it is possible to determine the deterioration pattern, more appropriate measures can be taken.

[0005] Therefore, this embodiment provides a deterioration diagnosis device and a deterioration diagnosis method that can determine the pattern of deterioration in a water heat exchanger that exchanges heat between water flowing in a water pipe and a refrigerant flowing in a refrigerant pipe.

[0006] The deterioration diagnosis device for a water heat exchanger according to this embodiment includes a water heat exchanger having a heat transfer unit between a water pipe through which water flows and a refrigerant pipe through which a refrigerant flows, and performing heat exchange between the water flowing in the water pipe and the refrigerant flowing in the refrigerant pipe via the heat transfer unit; a differential pressure flow rate specifying unit that specifies a flow rate estimated from a pressure difference between the water pressure in the water pipe upstream of the water heat exchanger and the water pressure in the water pipe downstream of the water heat exchanger as a differential pressure flow rate; a capacity flow rate specifying unit that estimates the flow rate of water flowing in the water pipe based on the 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 the temperature difference between the temperature of the water flowing in the water pipe and the temperature of the refrigerant flowing in the refrigerant pipe as an actual temperature difference; and a temperature difference specifying unit that estimates the temperature difference between the temperature of the water flowing in the water pipe and the temperature of the refrigerant flowing in the refrigerant pipe based on the capacity of the water heat exchanger and specifies the estimated temperature difference as a capacity flow rate. and a deterioration pattern determination unit that determines a deterioration pattern of the water heat exchanger based on the differential pressure flow rate determined by the differential pressure flow rate determination unit, the capacity flow rate determined by the capacity flow rate determination unit, the actual temperature difference determined by the actual temperature difference determination unit, and the estimated temperature difference determined by the estimated temperature difference determination unit.If the differential pressure flow rate determined by the differential pressure flow rate determination unit is greater than the capacity flow rate determined by the capacity flow rate determination unit, the deterioration pattern of the water heat exchanger is a flow path blockage pattern in which the water piping is blocked, and if the actual temperature difference determined by the actual temperature difference determination unit is greater than the estimated temperature difference determined by the estimated temperature difference determination unit, the deterioration pattern of the water heat exchanger is a heat transfer inhibition pattern in which the heat transfer property of the heat transfer section is inhibited.

[0007] The deterioration diagnosis method for a water heat exchanger according to this embodiment is a method for diagnosing deterioration of a water heat exchanger that includes a heat transfer unit between a water pipe through which water flows and a refrigerant pipe through which a refrigerant flows, and that performs heat exchange between the water flowing in the water pipe and the refrigerant flowing in the refrigerant pipe via the heat transfer unit, and includes the following steps: a differential pressure flow rate determination process that determines a flow rate estimated from a pressure difference between the water pressure in the water pipe upstream of the water heat exchanger and the water pressure in the water pipe downstream of the water heat exchanger as a differential pressure flow rate; a capacity flow rate determination process that estimates the flow rate of water flowing in the water pipe based on the capacity of the water heat exchanger and determines the estimated flow rate as a capacity flow rate; an actual temperature difference determination process that determines the temperature difference between the temperature of the water flowing in the water pipe and the temperature of the refrigerant flowing in the refrigerant pipe as an actual temperature difference; and an actual temperature difference determination process that estimates the temperature difference between the temperature of the water flowing in the water pipe and the temperature of the refrigerant flowing in the refrigerant pipe based on the capacity of the water heat exchanger and determines the estimated temperature difference. as an estimated temperature difference; and a deterioration pattern determination process that determines a deterioration pattern of the water heat exchanger based on the differential pressure flow rate determined by the differential pressure flow rate determination process, the capacity flow rate determined by the capacity flow rate determination process, the actual temperature difference determined by the actual temperature difference determination process, and the estimated temperature difference determined by the estimated temperature difference determination process. In the deterioration pattern determination process, if the differential pressure flow rate determined by the differential pressure flow rate determination process is greater than the capacity flow rate determined by the capacity flow rate determination process, the deterioration pattern of the water heat exchanger is determined to be a flow path blockage pattern in which the water piping is blocked, and if the actual temperature difference determined by the actual temperature difference determination process is greater than the estimated temperature difference determined by the estimated temperature difference determination process, the deterioration pattern of the water heat exchanger is determined to be a heat transfer inhibition pattern in which the heat transfer property of the heat transfer section is inhibited.

[0008] FIG. 1 is a diagram schematically showing an example of the configuration of a chiller system according to a first embodiment; FIG. 2 is a block diagram schematically showing an example of the configuration of a control device according to a second embodiment; FIG. 3 is a diagram schematically showing an example of the configuration of a chiller system according to a third embodiment; and FIG. 4 is a diagram schematically showing an example of the configuration of a chiller system according to a fourth embodiment.

[0009] Hereinafter, several embodiments of a deterioration diagnosis device and a deterioration diagnosis method for a water heat exchanger will be described with reference to the drawings. Note that substantially the same elements in several embodiments are given the same reference numerals, and descriptions thereof will be omitted.

[0010] 1 includes a refrigeration cycle unit 200 and a user-side unit 300. The chiller system 100 performs heat exchange between a refrigerant flowing through the refrigeration cycle unit 200 and water flowing through the user-side unit 300, thereby cooling or heating an object or space that is a temperature control target of 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 connected in sequence by the refrigerant pipe 208.

[0012] The compressor 201 is configured to be able to compress a refrigerant. The compressor 201 can change its operating frequency by, for example, known inverter control. The compressor 201 may also be configured so that its operating frequency cannot be changed, i.e., its operating frequency is fixed.

[0013] The air heat exchanger 202 is, for example, a fin-and-tube type heat exchanger. That is, the air heat exchanger 202 is a heat exchanger configured such that a refrigerant pipe 208 is inserted through a plurality of flat plate-shaped fins. A fan 203 is disposed near the air heat exchanger 202. The air heat exchanger 202 exchanges heat between the air sent from the fan 203 and the refrigerant passing through the air heat exchanger 202.

[0014] The expansion valve 204 is configured to have an adjustable valve opening. The expansion valve 204 includes, for example, a valve body having a through hole, a needle that can advance and retract relative to the through hole, and a power source that advances and retracts the needle. When the through hole is blocked by the needle, the expansion valve 204 blocks the flow of refrigerant in the refrigeration cycle unit 200. At this time, the expansion valve 204 is in a closed state, and the opening of the expansion valve 204 is at its smallest. 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 opening of the expansion valve 204 is at its largest.

[0015] The water heat exchanger 205 exchanges heat between water flowing in the water pipe 301 to be heated or cooled and the refrigerant flowing in the refrigerant pipe 208. The pump 302 pumps the water in the water pipe 301 toward 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 by sandwiching multiple stacked heat exchange plates between a pair of cover plates in the stacking direction. At least one of the cover plates has multiple joints that function as inlets and outlets for water and refrigerant. The water heat exchanger 205 is connected to a water pipe 301 through which water flows and a refrigerant pipe 208 through which refrigerant flows, and is provided with a heat transfer section 205a in which the water and refrigerant exchange heat by alternately separating the water flow path and the refrigerant flow path with plates.

[0017] The accumulator 206 has a case made of a metal such as steel. A liquid-phase refrigerant is accommodated in the lower part of the accumulator 206. A gas-phase refrigerant is accommodated in the upper part of the accumulator 206. The accumulator 206 supplies the gas-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 direction of refrigerant flow in the refrigerant pipe 208. In the heating operation state and the cooling operation state, the direction of refrigerant flow in the refrigerant pipe 208 is switched to the opposite direction.

[0019] When the refrigeration cycle unit 200 is switched to a heating operation state, the water flowing in the water pipe 301 is heated by the water heat exchanger 205. In the heating operation state, the refrigerant flows 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 to a high temperature in the compressor 201 condenses in the water heat exchanger 205 and exchanges heat with the water in the water pipe 301. This heats the water flowing through the water pipe 301. At this time, the water heat exchanger 205 functions as a condenser that condenses the refrigerant. The refrigerant that has exchanged heat with the water in the water heat exchanger 205 is depressurized in the expansion valve 204 and further exchanges heat with air blown by the fan 203 in the air heat exchanger 202. At this time, the air heat exchanger 202 functions as an evaporator that evaporates the refrigerant. The refrigerant that has exchanged heat with the air in the air heat exchanger 202 is returned to the compressor 201 via the accumulator 206, heated again, and sent to the water heat exchanger 205. By circulating the refrigerant in this manner, the water heat exchanger 205 heats the water flowing through the water pipe 301.

[0021] On the other hand, when the refrigeration cycle unit 200 is switched to a cooling operation state, the water flowing in the water pipe 301 is cooled by the water heat exchanger 205. In the cooling operation state, the refrigerant flows 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 to a high temperature in compressor 201 condenses in air heat exchanger 202 and exchanges heat with air blown by fan 203. At this time, air heat exchanger 202 functions as a condenser that condenses the refrigerant. The refrigerant that has exchanged heat with the air in air heat exchanger 202 is depressurized in expansion valve 204 and further exchanges heat with water in water pipe 301 in water heat exchanger 205. This cools the water flowing in water pipe 301. At this time, water heat exchanger 205 functions as an evaporator that evaporates the refrigerant. The refrigerant that has exchanged heat with the air in water heat exchanger 205 is returned to compressor 201 via accumulator 206, heated again, and sent to air heat exchanger 202. By circulating the refrigerant in this manner, water heat exchanger 205 cools the water flowing in water pipe 301.

[0023] Chiller system 100 is provided with an accumulator-side refrigerant pressure gauge 221 and an accumulator-side refrigerant thermometer 231 in a portion of refrigerant piping 208 closer to accumulator 206 than compressor 201. Chiller system 100 is also provided with an anti-accumulator-side refrigerant pressure gauge 222 and an anti-accumulator-side refrigerant thermometer 232 in a portion of refrigerant piping 208 on the opposite side of accumulator 206 than compressor 201.

[0024] The chiller system 100 is provided with an upstream water pressure gauge 321 and an upstream water temperature gauge 331 in the portion of the water piping 301 that is upstream of the water heat exchanger 205. The chiller system 100 is also provided with a downstream water pressure gauge 322 and a downstream water temperature gauge 332 in the portion of the water piping 301 that is downstream of the water heat exchanger 205.

[0025] Next, a detailed description will be given of the control device 400 that controls the chiller system 100. The control device 400 is configured, for example, mainly using a computer, and is capable of controlling the overall operation of the chiller system 100 based on a control program, various setting data, etc. The control device 400 also functions as an example of a deterioration diagnosis device for the water heat exchanger 205, and is configured to be able to diagnose deterioration of the water heat exchanger 205.

[0026] The control device 400 is connected to various drive system components such as the above-mentioned compressor 201, fan 203, expansion valve 204, four-way valve 207, pump 302, etc. The control device 50 is also connected to various sensor system components such as the above-mentioned accumulator-side refrigerant pressure gauge 221, accumulator-side refrigerant thermometer 231, counter-accumulator-side refrigerant pressure gauge 222, counter-accumulator-side refrigerant thermometer 232, upstream-side water pressure gauge 321, upstream-side water thermometer 331, downstream-side water pressure gauge 322, downstream-side water thermometer 332, etc.

[0027] 2, the control device 400 executes a degradation diagnosis program to virtually realize, by software, a differential pressure flow rate identification processing unit 401, a capacity flow rate identification processing unit 402, an actual temperature difference identification processing unit 403, an estimated temperature difference identification processing unit 404, a degradation pattern determination processing unit 405, and a notification processing unit 406. Note that the differential pressure flow rate identification processing unit 401, the capacity flow rate identification processing unit 402, the actual temperature difference identification processing unit 403, the estimated temperature difference identification processing unit 404, the degradation pattern determination processing unit 405, and the notification processing unit 406 may be realized by hardware or a combination of software and hardware.

[0028] The differential pressure flow rate determining process 401 is an example of a differential pressure flow rate determining process, and is capable of executing a differential pressure flow rate determining process. The differential pressure flow rate determining process is a process for determining, as a differential pressure flow rate, a flow rate estimated from the pressure difference between the water pressure detected by the upstream water pressure gauge 321 in the portion of the water piping 301 upstream of the water heat exchanger 205 and the water pressure detected by the downstream water pressure gauge 322 in the portion of the water piping 301 downstream of the water heat exchanger 205. In other words, the larger the pressure difference between the water pressure upstream of the water heat exchanger 205 and the water pressure downstream of the water heat exchanger 205, the larger the water flow rate can be estimated to be, and conversely, the smaller the pressure difference, the smaller the water flow rate can be estimated to be.

[0029] The capacity flow rate specification processing unit 402 is an example of a capacity flow rate specification unit and is capable of executing a capacity flow rate specification process. The capacity flow rate specification process is a process of estimating the flow rate of water flowing through the water pipe 301 based on the capacity of the water heat exchanger 205 and specifying the estimated flow rate as the capacity flow rate.

[0030] The capacity of the water heat exchanger 205 can be estimated based on the enthalpy change of the refrigerant flowing through the refrigerant pipe 208, the amount of refrigerant circulating through the refrigerant pipe 208, and the like. The enthalpy change of the refrigerant flowing through the refrigerant pipe 208 can be calculated based on the pressure of the refrigerant flowing through the refrigerant pipe 208 detected by the accumulator-side refrigerant pressure gauge 221 and the anti-accumulator-side refrigerant pressure gauge 222, and the temperature of the refrigerant flowing through the refrigerant pipe 208 detected by the accumulator-side refrigerant thermometer 231 and the anti-accumulator-side refrigerant thermometer 232, and the like. The amount of refrigerant circulating through the refrigerant pipe 208 can be calculated based on the drive frequency of the compressor 201, the density of the refrigerant filled in the refrigerant pipe 208, and the like. The density of the refrigerant filled in the refrigerant pipe 208 varies mainly depending on the type of refrigerant, but can also vary depending on the amount of refrigerant filled, the ambient temperature, and the like.

[0031] The capacity of the water heat exchanger 205 can be estimated more accurately by also reflecting changes in the temperature of the water flowing through the water pipe 301 detected by the upstream water thermometer 331 and the downstream water thermometer 332.

[0032] The actual temperature difference identification processor 403 is an example of an actual temperature difference identification unit and is capable of executing an actual temperature difference identification process. The actual temperature difference identification process is a process for identifying the temperature difference between the temperature of the water flowing in the water pipe 301 and the temperature of the refrigerant flowing in the refrigerant pipe 208 in the water heat exchanger 205 as an actual temperature difference. In other words, the actual temperature difference can be defined as the temperature difference between the water and the refrigerant flowing in the water heat exchanger 205. The temperature of the water flowing in the water pipe 301 in the water heat exchanger 205 can be detected by the upstream water thermometer 331 and the downstream water thermometer 332. The temperature of the refrigerant flowing in the refrigerant pipe 208 can be detected by the accumulator-side refrigerant thermometer 231 and the anti-accumulator-side refrigerant thermometer 232.

[0033] The estimated temperature difference determination processing unit 404 is an example of an estimated temperature difference determination unit and is capable of executing an estimated temperature difference determination process. The estimated temperature difference determination process is a process of estimating the temperature difference between the temperature of the water flowing in the water pipe 301 and the temperature of the refrigerant flowing in the refrigerant pipe 208 in the water heat exchanger 205 based on the capacity of the water heat exchanger 205, and identifying the estimated temperature difference as the 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 flowing in the refrigerant piping 208 and the amount of refrigerant circulating in the refrigerant piping 208, and can be estimated more accurately by also reflecting the change in the temperature of the water flowing in the water piping 301.

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

[0036] More specifically, if the differential pressure flow rate identified by the differential pressure flow rate identification processing processing unit 401 is greater than the capacity flow rate identified by the capacity flow rate identification processing processing unit 402 by a predetermined reference amount or more, the deterioration pattern determination processing unit 405 determines that the deterioration pattern of the water heat exchanger 205 is a "flow path blockage pattern." The flow path blockage pattern is a deterioration pattern in which scale has adhered to the water pipe 301, causing blockage inside the water pipe 301. The predetermined reference amount for determining whether or not a "flow path blockage pattern" has occurred can be changed and set as appropriate.

[0037] Furthermore, if the actual temperature difference identified by the actual temperature difference identification processing processing unit 403 is greater than the estimated temperature difference identified by the estimated temperature difference identification processing processing unit 404 by a predetermined reference amount or more, the deterioration pattern determination processing unit 405 determines that the deterioration pattern of the water heat exchanger 205 is a "heat transfer inhibition pattern." The heat transfer inhibition pattern is a deterioration pattern in which scale adheres to the heat transfer section 205a, inhibiting the heat transfer of the heat transfer section 205a. The predetermined reference amount for determining whether or not a "heat transfer inhibition pattern" has occurred can be changed and set as appropriate.

[0038] In the water heat exchanger 205, there may be cases where only deterioration in the "flow path blockage pattern" has occurred, cases where only deterioration in the "heat transfer inhibition pattern" has occurred, or cases where deterioration in both the "flow path blockage pattern" and the "heat transfer inhibition pattern" has occurred simultaneously.

[0039] The notification processing unit 406 is an example of a notification unit and is capable of executing notification processing. The notification processing is processing for notifying the result of the deterioration pattern determination by the deterioration pattern determination processing unit 405. The notification processing may, for example, be performed as visual information via a display output device (not shown) provided in the control device 400, as auditory information via an audio output device (not shown) provided in the control device 400, or as both visual and auditory information. The display output device is, for example, a display, etc. The audio output device is, for example, a speaker, etc.

[0040] If the deterioration pattern determination processing unit 405 determines that the deterioration pattern is a "flow path blockage pattern," the notification processing unit 406 notifies the water heat exchanger 205 that deterioration in the "flow path blockage pattern" has occurred. Furthermore, if the deterioration pattern determination processing unit 405 determines that the deterioration pattern is a "heat conductivity obstruction pattern," the notification processing unit 406 notifies the water heat exchanger 205 that deterioration in the "heat conductivity obstruction pattern" has occurred.

[0041] Furthermore, when the deterioration pattern determination processing unit 405 determines that the deterioration pattern is both the "flow path blockage pattern" and the "heat transfer inhibition pattern," the notification processing unit 406 may be configured to notify that deterioration in the "flow path blockage pattern" and deterioration in the "heat transfer inhibition pattern" has occurred in the water heat exchanger 205, or may be configured to notify only one of the deterioration patterns. When notifying only one of the deterioration patterns, for example, a deterioration pattern with a greater degree of deterioration may be selected and notified, or a deterioration pattern previously designated by the user may be notified.

[0042] The control device 400 of the chiller system 100 described above can determine whether the deterioration pattern of the water heat exchanger 205 is a "flow path blockage pattern" or a "heat transfer inhibition pattern" based on the magnitude relationship between the differential pressure flow rate determined by the differential pressure flow rate determination processor 401 and the capacity flow rate determined by the capacity flow rate determination processor 402, and the magnitude relationship between the actual temperature difference determined by the actual temperature difference determination processor 403 and the estimated temperature difference determined by the estimated temperature difference determination processor 404. Furthermore, in some cases, deterioration of both the "flow path blockage pattern" and the "heat transfer inhibition pattern" may occur simultaneously in the water heat exchanger 205. In such cases, it can be determined that both the "flow path blockage pattern" and the "heat transfer inhibition pattern" have occurred simultaneously. This makes it possible to determine the type of deterioration pattern of the water heat exchanger 205, which exchanges heat between the water flowing in the water pipe 301 and the refrigerant flowing in the refrigerant pipe 208, and to take more appropriate measures depending on the deterioration pattern that has occurred.

[0043] In both of the two types of deterioration patterns, the "flow path blockage pattern" and the "heat transfer inhibition pattern," the flow paths in the water pipe 301 eventually become blocked. However, in the initial stage, that is, when the flow paths begin to become blocked, the following differences are observed between the respective deterioration patterns. That is, in the "flow path blockage pattern," there is a significant increase in pressure loss of the water flowing in the water pipe 301, while in the "heat transfer inhibition pattern," there is a significant deterioration in the heat transfer performance of the heat transfer section 205a.

[0044] Therefore, by comparing the magnitude relationship between the differential pressure flow rate determined by the differential pressure flow rate determining processor 401 and the capacity flow rate determined by the capacity flow rate determining processor 402, it is possible to determine whether a "flow path blockage pattern" has occurred. That is, when scale clogs the water pipe 301, the pressure loss of the water flowing through the water pipe 301 increases. When the pressure loss of the water flowing through the water pipe 301 increases, the differential pressure flow rate determined by the differential pressure flow rate determining processor 401 is likely to increase due to the increased pressure loss, but the capacity flow rate determined by the capacity flow rate determining processor 402 is based on the capacity of the water heat exchanger 205 and is therefore less susceptible to the increased pressure loss and therefore less likely to change. Therefore, when the differential pressure flow rate determined by the differential pressure flow rate determining processor 401 is sufficiently larger than the capacity flow rate determined by the capacity flow rate determining processor 402, it can be determined that the deterioration pattern of the water heat exchanger 205 is a "flow path blockage pattern."

[0045] Furthermore, by comparing the magnitude relationship between the actual temperature difference identified by the actual temperature difference identification processor 403 and the estimated temperature difference identified by the estimated temperature difference identification processor 404, it is possible to determine whether a "heat transfer inhibition pattern" has occurred. That is, when scale adheres to the heat transfer section 205a, the heat transfer performance of the heat transfer section 205a deteriorates. When the heat transfer performance of the heat transfer section 205a deteriorates, the actual temperature difference identified by the actual temperature difference identification processor 403 tends to increase due to the deterioration of heat transfer performance. However, the estimated temperature difference identified by the estimated temperature difference identification processor 404 is based on the capacity of the water heat exchanger 205 and is therefore less susceptible to the deterioration of heat transfer performance and therefore less likely to change. Therefore, when the actual temperature difference identified by the actual temperature difference identification processor 403 is significantly larger than the estimated temperature difference identified by the estimated temperature difference identification processor 404, it can be determined that the deterioration pattern of the water heat exchanger 205 is a "heat transfer inhibition pattern."

[0046] As described above, the present application discloses an embodiment that makes it possible to determine the pattern in which the water heat exchanger 205 is deteriorating by focusing on the significant differences between deterioration patterns observed in the early stages of flow path blockage.

[0047] Second Embodiment The control device 400 illustrated in Fig. 3 is configured to include an actual flow rate specifying processor 407 instead of the capacity flow rate specifying processor 402. The control device 400 executes a degradation diagnosis program to virtually realize the actual flow rate specifying processor 407 in software. Note that the actual flow rate specifying processor 407 may be realized in hardware or a combination of software and hardware.

[0048] The actual flow rate identification processing unit 407 is an example of an actual flow rate identification unit, and is capable of executing an actual flow rate identification process. The actual flow rate identification process is a process for identifying the flow rate of water actually flowing through the water pipe 301 as the actual flow rate. The flow rate of water actually flowing through the water pipe 301 can be detected by a flow meter 341 illustrated in FIG. 4. In this case, the flow meter 341 is provided in a portion of the water pipe 301 that is upstream of the water heat exchanger 205. However, the flow meter 341 may also be provided in a portion of the water pipe 301 that is downstream of the water heat exchanger 205, or in a portion of the water pipe 301 within the water heat exchanger 205, as long as the portion is capable of detecting the flow rate of water actually flowing through the water pipe 301.

[0049] The deterioration pattern determination processing unit 405 determines that the deterioration pattern of the water heat exchanger 205 is a ``flow path blockage pattern'' if the differential pressure flow rate identified by the differential pressure flow rate identification processing unit 401 is greater than a predetermined standard amount than the actual flow rate identified by the actual flow rate identification processing unit 407.

[0050] The second embodiment also makes it possible to determine the pattern of deterioration of the water heat exchanger 205, which exchanges heat between the water flowing in the water pipe 301 and the refrigerant flowing in the refrigerant pipe 208.

[0051] Furthermore, the differential pressure flow rate determined by the differential pressure flow rate determination processing unit 401 can be compared with an actual measured value rather than an estimated value, making it possible to more accurately determine whether a "flow path blockage pattern" has occurred.

[0052] In the second embodiment, the control device 400 includes an actual flow rate specifying processing unit 407 together with the capacity flow rate specifying processing unit 402, and may appropriately select either the capacity flow rate specified by the capacity flow rate specifying processing unit 402 or the actual flow rate specified by the actual flow rate specifying processing unit 407 and compare it with the differential pressure flow rate specified by the differential pressure flow rate specifying processing unit 401. Alternatively, 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 may be specified as an average, median, maximum, minimum, etc., and the specified value may be compared with the differential pressure flow rate specified by the differential pressure flow rate specifying processing unit 401.

[0053] (Third embodiment) The chiller system 100 illustrated in FIG. 5 is configured to have multiple, in this case two, refrigeration cycle units 200 for one user unit 300. In other words, multiple, in this case two, refrigerant pipes 208 are associated with one water pipe 301.

[0054] In this configuration example, the deterioration pattern determination processing unit 405 is able to determine the deterioration pattern using the capacity of the water heat exchanger 205 estimated in relation to one refrigerant pipe 208 and the water pipe 301, and is also able to determine the deterioration pattern using the capacity of the water heat exchanger 205 estimated in relation to the other refrigerant pipe 208 and the water pipe 301.

[0055] When a deterioration pattern is determined using the capacity of the water heat exchanger 205 estimated in the relationship between one refrigerant pipe 208 and the water pipe 301, the notification processing unit 406 can issue a notification that deterioration has occurred in the relationship with that one refrigerant pipe 208. When a deterioration pattern is determined using the capacity of the water heat exchanger 205 estimated in the relationship between the other refrigerant pipe 208 and the water pipe 301, the notification processing unit 406 can issue a notification that deterioration has occurred in the relationship with the other refrigerant pipe 208. That is, according to this configuration example, it is possible to identify which of the multiple refrigerant pipes 208 the water heat exchanger 205 is in relation to and, ultimately, which of the multiple refrigeration cycle units 200 the water heat exchanger 205 is in relation to.

[0056] In addition, even if a deterioration pattern is determined using the capacity of the water heat exchanger 205 estimated in relation to the relationship between any one of the multiple refrigerant pipes 208 and the water pipe 301, the notification processing unit 406 may be configured to notify that deterioration has occurred in the water heat exchanger 205 in relation to all of the multiple refrigerant pipes 208, including the other refrigerant pipes 208.

[0057] 6 is configured such that a plurality of water heat exchangers 205, in this case two, are connected in series on a single water pipe 301. An intermediate water pressure gauge 323 and an intermediate water temperature gauge 333 are provided in the water pipe 301 in a portion between the plurality of water heat exchangers 205. That is, the configuration example of the fourth embodiment is configured such that a plurality of the configurations exemplified in the first embodiment described above, in this case two, are connected in series. According to this configuration example, the deterioration pattern determination processing unit 405 can determine the deterioration pattern for each of the plurality of water heat exchangers 205.

[0058] When a deterioration pattern is determined for one of the water heat exchangers 205, the notification processing unit 406 can issue a notification that deterioration has occurred in that one of the water heat exchangers 205. Furthermore, when a deterioration pattern is determined for the other of the water heat exchangers 205, the notification processing unit 406 can issue a notification that deterioration has occurred in the other of the water heat exchangers 205. In other words, according to this configuration example, it is possible to identify which of the water heat exchangers 205 has deteriorated.

[0059] In addition, even if a deterioration pattern is determined to exist in any one of the multiple water heat exchangers 205, the notification processing unit 406 may be configured to notify that deterioration has occurred in the entire group of multiple water heat exchangers 205, including the other water heat exchangers 205.

[0060] (Other Embodiments) Note that this embodiment is not limited to the above-described embodiments, and various modifications and extensions can be made without departing from the spirit of the present invention. For example, an embodiment may be formed by appropriately combining at least two or more of the above-described embodiments. Furthermore, the differential pressure flow rate, capacity flow rate, actual temperature difference, and estimated temperature difference are not limited to the above-described identification methods, and can be identified using various well-known methods.

[0061] Although several embodiments of the present invention have been described above, these embodiments are presented merely as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, modifications, etc. can be made without departing from the spirit of the invention. The present embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention described in the claims and their equivalents.

[0062] In the drawing, 205 indicates a water heat exchanger, 205a indicates a heat transfer section, 208 indicates a refrigerant piping, 301 indicates a water piping, 400 indicates a control device (water heat exchanger deterioration diagnosis device), 401 indicates a differential pressure flow rate identification processing section (differential pressure flow rate identification section), 402 indicates a capacity flow rate identification processing section (capacity flow rate identification section), 403 indicates an actual temperature difference identification processing section (actual temperature difference identification section), 404 indicates an estimated temperature difference identification processing section (estimated temperature difference identification section), 405 indicates a deterioration pattern determination processing section (deterioration pattern determination section), and 407 indicates an actual flow rate identification processing section (actual flow rate identification section).

Claims

1. A water heat exchanger having a heat transfer unit between a water pipe through which water flows and a refrigerant pipe through which a refrigerant flows, exchanging heat between the water flowing in the water pipe and the refrigerant flowing in the refrigerant pipe via the heat transfer unit; a differential pressure flow rate determination unit that determines a flow rate estimated from a pressure difference between the water pressure in the water pipe upstream of the water heat exchanger and the water pressure in the water pipe downstream of the water heat exchanger as a differential pressure flow rate; a capacity flow rate determination unit that estimates the flow rate of water flowing in the water pipe based on the capacity of the water heat exchanger and determines the estimated flow rate as a capacity flow rate; an actual temperature difference determination unit that determines the temperature difference between the temperature of the water flowing in the water pipe and the temperature of the refrigerant flowing in the refrigerant pipe as an actual temperature difference; and an estimated temperature difference determination unit that estimates the temperature difference between the temperature of the water flowing in the water pipe and the temperature of the refrigerant flowing in the refrigerant pipe based on the capacity of the water heat exchanger and determines the estimated temperature difference as an estimated temperature difference. a deterioration pattern determination unit that determines a deterioration pattern of the water heat exchanger based on the differential pressure flow rate identified by the differential pressure flow rate identifying unit, the capacity flow rate identified by the capacity flow rate identifying unit, the actual temperature difference identified by the actual temperature difference identifying unit, and the estimated temperature difference identified by the estimated temperature difference identifying unit, wherein the deterioration pattern determination unit determines that the deterioration pattern of the water heat exchanger is a flow path blockage pattern in which the water piping is blocked, if the differential pressure flow rate identified by the differential pressure flow rate identifying unit is greater than the capacity flow rate identified by the capacity flow rate identifying unit, and determines that the deterioration pattern of the water heat exchanger is a heat transfer inhibition pattern in which the heat transfer property of the heat transfer section is inhibited, if the actual temperature difference identified by the actual temperature difference identifying unit is greater than the estimated temperature difference identified by the estimated temperature difference identifying unit.

2. A deterioration diagnosis device for a water heat exchanger as described in claim 1, further comprising an actual flow rate determination unit which determines the flow rate of water actually flowing within the water piping as the actual flow rate, and wherein the deterioration pattern determination unit determines that the deterioration pattern of the water heat exchanger is the flow path blockage pattern if the differential pressure flow rate determined by the differential pressure flow rate determination unit is greater than the actual flow rate determined by the actual flow rate determination unit.

3. A method for diagnosing deterioration of a water heat exchanger having a heat transfer unit between a water piping through which water flows and a refrigerant piping through which a refrigerant flows, and exchanging heat between the water flowing in the water piping and the refrigerant flowing in the refrigerant piping via the heat transfer unit, comprising: a differential pressure flow rate determination process for determining a flow rate estimated from a pressure difference between the water pressure in the water piping upstream of the water heat exchanger and the water pressure in the water piping downstream of the water heat exchanger as a differential pressure flow rate; a capacity flow rate determination process for estimating the flow rate of water flowing in the water piping based on the capacity of the water heat exchanger and determining the estimated flow rate as a capacity flow rate; an actual temperature difference determination process for determining the temperature difference between the temperature of the water flowing in the water piping and the temperature of the refrigerant flowing in the refrigerant piping as an actual temperature difference; and an estimated temperature difference determination process for estimating the temperature difference between the temperature of the water flowing in the water piping and the temperature of the refrigerant flowing in the refrigerant piping based on the capacity of the water heat exchanger and determining the estimated temperature difference as an estimated temperature difference. a deterioration pattern determination process for determining a deterioration pattern of the water heat exchanger based on the differential pressure flow rate identified by the differential pressure flow rate identification process, the capacity flow rate identified by the capacity flow rate identification process, the actual temperature difference identified by the actual temperature difference identification process, and the estimated temperature difference identified by the estimated temperature difference identification process, wherein the deterioration pattern determination process determines that the deterioration pattern of the water heat exchanger is a flow path blockage pattern in which the water piping is blocked, if the differential pressure flow rate identified by the differential pressure flow rate identification process is greater than the capacity flow rate identified by the capacity flow rate identification process, and determines that the deterioration pattern of the water heat exchanger is a heat transfer inhibition pattern in which the heat transfer property of the heat transfer section is inhibited, if the actual temperature difference identified by the actual temperature difference identification process is greater than the estimated temperature difference identified by the estimated temperature difference identification process.

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