JP3054553B2 - Absorption chiller / heater failure diagnosis device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for diagnosing a failure of an absorption chiller / heater.

[0002]

2. Description of the Related Art As shown in FIG. 5, an absorption chiller / heater has a condenser (11) and a low-temperature regenerator (12) disposed on an upper body (1) and an evaporator disposed on a lower body (2). Vessel (21) and absorber (22), burner
A high-temperature regenerator (3) equipped with (31), a high-temperature heat exchanger (4), a low-temperature heat exchanger (5), etc., are connected to each other by piping, and an absorbent pump (6).
Thus, the absorbing liquid is circulated between the high-temperature regenerator (3), the low-temperature regenerator (12) and the absorber (22) to realize a refrigeration cycle or a heat release cycle. Evaporator (21) and condenser
Cooling water from a cooling tower (not shown) flows through the cooling water pipe passing through (11).

In the meantime, in the absorption type chiller / heater, various abnormalities may occur, such as contamination of the cooling water, an abnormality in the circulating amount of the absorbing liquid, an abnormality in the degree of vacuum, and mixing of the absorbing liquid into the refrigerant (refrigerant mixing). There is. As the cooling water stain progresses, foreign matter such as dust adheres to the inner surface of the cooling water pipe, lowering the heat transfer coefficient, and
Since the cooling effect in (22) becomes insufficient, the temperature of the absorbing liquid increases, the steam pressure in the lower body (2) increases, and the refrigeration capacity decreases. As a result, the amount of heat input to the high-temperature regenerator (3) increases in order to supply the cold water at the target temperature, and the concentration of the absorbing liquid increases.

[0004] When the absorbing liquid is mixed with the refrigerant, the boiling point of the refrigerant rises and the performance of the evaporator (21) and the absorber (22) is reduced. Also, when the degree of vacuum in the lower body (2) is reduced, the evaporator (2) is also used.
1) and the capacity of the absorber (22) will be reduced. As a result, the amount of heat input to the high-temperature regenerator (3) similarly increases, and the concentration of the absorbing solution increases.

As described above, since various abnormalities cause an increase in the concentration of the absorbing solution, the concentration of the absorbing solution is monitored in order to detect the degree of the overall abnormality of the absorption type chiller / heater. In particular, the low-temperature heat exchanger (12)
The increase in the concentration of the absorbing liquid (concentrated liquid) supplied to the absorber (22) through (5) directly causes the crystallization of the absorbing liquid, which may cause the operation of the water heater / heater to be stopped. Therefore, the concentration of the concentrated liquid is used as an index for monitoring such an abnormality.

FIG. 4 is a graph showing the relationship between the refrigeration load and the concentration of the concentrated liquid when the absorption chiller / heater is in a normal operation state, using the cooling water inlet temperature as a parameter. A deviation between the measured value of the concentrated solution concentration and the normal value of the concentrated solution concentration shown in FIG. 4 is calculated, and when the concentrated solution concentration deviation exceeds a predetermined evaluation reference value, it is determined that an abnormality has occurred. I can do it.

On the other hand, in order to detect an abnormality of various heat exchangers such as the condenser (11) and the absorber (22), an abnormality degree A represented by the following equation 2 is defined, and based on the abnormality degree, Diagnosis of various failures is performed.

A = (ΔT−ΔTn) / ΔTn where ΔT is a measured value of the logarithmic average temperature difference, and ΔTn is a normal value of the logarithmic average temperature difference.

[0008]

The absorber (22)
In addition, since the cooling water flowing through the cooling water pipe in the condenser (11) comes into contact with the outside air in the process of circulating between the cooling tower and the cooling tower, it is inevitable that foreign matters such as dust and dirt are mixed. These foreign substances adhere to the inner surface of the cooling water pipe as the operation time elapses, and lower the heat transfer coefficient. Since the problem of such cooling water contamination is essentially different from the problem of refrigerant mixing and vacuum abnormality caused by the failure of the chiller / heater itself, it is appropriate to distinguish the cooling water contamination from other abnormalities. .

However, in the conventional failure diagnosis, it was not possible to distinguish between cooling water contamination and other causes, and thus there was a problem that accurate failure diagnosis was difficult. SUMMARY OF THE INVENTION An object of the present invention is to provide a failure diagnosis device that can eliminate the influence of cooling water contamination when detecting an abnormality in the concentration of a concentrated liquid, thereby realizing accurate failure diagnosis.

[0010]

SUMMARY OF THE INVENTION A failure diagnosis apparatus for an absorption type chiller / heater according to the present invention comprises a temperature measuring means for measuring the temperatures of a refrigerant and a cooling water which exchange heat in a condenser, and a temperature measuring means. Based on the measurement data, temperature difference data representing the average temperature difference between the refrigerant and the cooling water is calculated, and the temperature difference data is compared with its normal value to calculate abnormality degree data representing the degree of abnormality of the condenser. Device abnormality degree data calculating means, a concentrated liquid concentration deriving means for deriving the concentrated liquid concentration by measurement or estimation based on the measured data, and a concentrated liquid concentration deviation calculating means for calculating a deviation between the derived concentrated liquid concentration and a normal value thereof And a concentrated liquid concentration deviation correcting means for correcting the calculated concentrated liquid concentration deviation according to the size of the calculated condenser abnormality degree data.

In a specific configuration, the logarithmic average temperature difference can be used as the temperature difference data, and the degree of abnormality A defined by the equation 2 can be used as the degree of abnormality data.

[0012]

[Action] In the absorption type chiller / heater, the cooling water is supplied to the absorber (2
After passing through 2), it passes through a condenser (11). Therefore, when cooling water contamination occurs, not only the absorber (22) but also the condenser
The effect appears in (11). By the way, generally a condenser
(11) is arranged on the upper body (1) and is separated from the absorber (22) of the lower body (2) by a partition. Therefore, the vacuum abnormality of the absorber (22) and the influence of refrigerant mixing do not appear in the condenser (11).
As a cause of the abnormality of (11) and the absorber (22), the contamination of cooling water is common. Therefore, the condenser (11) and the absorber (22)
Abnormalities are linked to each other for cooling water contamination,
There will be a certain correlation between the two. On the other hand, as for the absorber (22), when the cooling water is contaminated, the heat transfer coefficient of the cooling water pipe is reduced as described above, and the cooling effect in the absorber (22) becomes insufficient. The deviation increases.

As described above, the change in the degree of abnormality of the condenser and the change in the concentration deviation of the concentrated liquid are linked to each other with respect to the contamination of the cooling water, and there is a certain correlation between the two. FIG. 3 qualitatively shows the correlation between the two. In an operation state in which all the abnormalities except for the cooling water contamination are eliminated, the condenser with time elapses, that is, with the progress of the cooling water contamination. (11)
The abnormal degree Acond and the concentrated solution concentration deviation dDs_dco are increasing at a constant rate.
Therefore, by multiplying the condenser abnormality degree by an appropriate correction coefficient, it is possible to estimate the deviation of the concentration of the concentrated liquid caused only by the cooling water contamination.

Therefore, in the present invention, the abnormal degree data representing the abnormal degree of the condenser (11) is calculated, and the concentrated liquid concentration deviation is corrected according to the magnitude of the abnormal degree data. The correction amount of the data can be calculated, for example, by multiplying the condenser abnormality degree data by a correction coefficient. In this case, the correction amount is subtracted from the concentrated concentration deviation to obtain the corrected concentrated concentration deviation. Get.

In general, the corrected concentrated concentration deviation dD
s' is, as shown in the following equation 3, a concentrated liquid concentration deviation dDs caused only by the cooling water stain from the concentrated liquid concentration deviation dDs based on the measurement.
It is obtained by subtracting Ds_dco.

## EQU3 ## dDs' = dDs-dDs_dco

Here, the concentrated liquid concentration deviation dDs_dco can be defined as a function f of the degree of abnormality Acond of the condenser as shown in the following equation 4, and this function is experimentally determined in advance.

## EQU4 ## dDs_dco = f (Acond)

FIG. 2 shows the influence of the cooling water stain included in the change of the concentrated liquid concentration deviation when the cooling water stain and other abnormalities occur, and the influence of other causes. By subtracting the influence of the cooling water stain calculated by the above equation 4 from the concentrated liquid concentration deviation, the influence other than the cooling water stain can be quantitatively grasped.

[0018]

According to the failure diagnosis apparatus for an absorption type water heater / cooler according to the present invention, the influence of cooling water contamination can be eliminated when judging the abnormality of the concentrated liquid concentration. Failure diagnosis can be performed.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a double effect absorption type chiller / heater shown in FIG. 5 will be described in detail with reference to the drawings. The chiller / heater uses water as a refrigerant and lithium bromide as an absorbing liquid. When supplying cold water, the refrigerant evaporated in the high-temperature regenerator (3) passes through the low-temperature regenerator (12) to the condenser (11). The heat exchanges with the cooling water flowing in the condenser (11) to condense and liquefy, and then flows toward the evaporator (21). Then, the liquefied refrigerant evaporates by exchanging heat with cold water flowing in the evaporator (21),
Cold water flowing in the evaporator (21) is cooled by the heat of vaporization at that time.

The refrigerant evaporated in the evaporator (21) is supplied to the absorber (22)
Is absorbed by the absorbing liquid. The absorption liquid whose concentration has been reduced by absorbing the refrigerant is subjected to a low-temperature heat exchanger by an absorption liquid pump (6).
It is sent to the high temperature regenerator (3) via (5) and the high temperature heat exchanger (4). The absorption liquid sent to the high temperature regenerator (3) is burner (31)
As a result, the refrigerant evaporates and the medium-absorbent liquid flows through the high-temperature heat exchanger (4) to the low-temperature regenerator (12). In the low-temperature regenerator (12), the absorbing liquid is heated by the refrigerant vapor from the high-temperature regenerator (3), and the refrigerant vapor is further separated to increase the concentration. The high-concentration absorbent is sent to the absorber (22) via the low-temperature heat exchanger (5) and is sprayed.

A piping connected to a heat exchanger such as an absorber (22), an evaporator (21), and a condenser (11) includes a cooling water inlet temperature sensor (71) and a cooling water intermediate temperature sensor (72). , Absorbent inlet temperature sensor (73), Absorbent outlet temperature sensor (74), Chilled water inlet temperature sensor (76), Chilled water outlet temperature sensor (77), Condensed refrigerant temperature sensor (79), Cooling water outlet temperature sensor (70 ), A low-temperature regenerator temperature sensor (701), an upper body pressure sensor (702), and the like.

FIG. 1 shows a configuration of a failure diagnosis apparatus according to the present invention. Various measurement data obtained from the above-mentioned sensor group (7) are supplied to an arithmetic unit (8) composed of a microcomputer, and are described later. The abnormality detection is performed as described above, and the failure is determined. The determination result is output to a display device (9) such as a display, a printer, and a warning lamp.

The arithmetic unit (8) includes calculation circuits (81) to (89) to be described later, each of which is constituted by a computer program, and an abnormality detection circuit (80). Upper body saturated steam temperature calculation circuit (8
1) is the upper body saturated steam temperature Tc from the pressure Pup in the upper body obtained from the upper body pressure sensor (702) using the following equation (5).
on is calculated.

[0024]

Tcond = [− b + {b ² −4 · c · (a−lnPup)} ^0.5 ] / {2
・ (A−lnPup)} − 237.0 where a, b, and c are constants and are 8.0509, −168, respectively.
Set to 5.1, -90991.

The condenser logarithmic average temperature difference calculating circuit (82) includes an upper body saturated steam temperature Tcond obtained from the upper body saturated steam temperature calculating circuit (81) and a cooling water obtained from the cooling water outlet temperature sensor (70). Outlet temperature Tco_out and cooling water intermediate temperature Tco_m obtained from cooling water intermediate temperature sensor (72)
The logarithmic average temperature difference ΔTcond of the condenser (11) is calculated from the id by using the following equation (6).

[0026]

ΔTcond = {(Tcond−Tco_mid) + (Tcond−Tco_ou)
t)} / ln {(Tcond-Tco_mid) / (Tcond-Tco_out)}

The refrigeration load calculation circuit (83) calculates the chilled water flow rate Vc obtained from the chilled water flow rate sensor (78), the chilled water outlet temperature Tc_out obtained from the chilled water outlet temperature sensor (77), and the chilled water inlet temperature sensor (76). Obtained cold water inlet temperature Tc
_In is used to calculate the refrigeration load Lc using Equation 7 below.

[0028]

Lc = Vc × (Tc_out−Tc_in)

A circuit for calculating a normal value of the logarithmic average temperature difference of the condenser (84)
Calculates the normal value ΔTcond_n of the logarithmic average temperature difference of the condenser (11) from the refrigeration load Lc obtained from the refrigeration load calculation circuit (83) using the following equation (8).

[0030]

ΔTcond_n = A × Lc Here, A is a constant determined by the characteristics of the absorption-type water heater / cooler, and is obtained experimentally.

The concentrated liquid concentration estimating circuit (85) calculates the low temperature regenerator temperature Ts_hi obtained from the low temperature regenerator temperature sensor (701).
And the concentration Ds of the concentrated liquid is estimated from the upper body saturated steam temperature Tcond obtained from the upper body saturated steam temperature calculation circuit (81) using the following equation (9).

[0032]

Ds = {(Ts_hi−283.0) × 139.0} / (Tcond + 273.0) −102.4

The concentrated liquid concentration normal value calculation circuit (86) calculates the cooling water inlet temperature Tco_in from the cooling water inlet temperature sensor (71).
Then, the normal value Ds_n of the concentration of the concentrated liquid is calculated from the refrigeration load Lc from the refrigeration load calculation circuit (83) using the graph shown in FIG. Here, in the graph of FIG. 4, the change of the concentrated liquid concentration is approximated by a quadratic function for each of the plurality of cooling water inlet temperatures, and the concentrated liquid concentration at an arbitrary cooling water inlet temperature is calculated by interpolation calculation. You.

The condenser abnormality degree calculating circuit (87) calculates a logarithmic average temperature difference ΔTcond of the condenser (11) obtained from the condenser logarithmic average temperature difference calculating circuit (82), and calculates a normal value of the condenser logarithmic average temperature difference. From the normal value ΔTcond_n of the logarithmic average temperature difference of the condenser (11) obtained from the circuit (84), the degree of abnormality Acond of the condenser (11) is calculated using the following equation (10).

[0035]

Acond = (ΔTcond−ΔTcond)
_N) / ΔTcond_n

The concentrated liquid concentration deviation calculating circuit (88) includes a concentrated liquid concentration Ds obtained from the concentrated liquid concentration estimating circuit (85) and a concentrated liquid concentration normal value obtained from the concentrated liquid concentration normal value calculating circuit (86). Ds_n
Is used to calculate the concentrated solution concentration deviation dDs using the following equation (11).

[0037]

## EQU11 ## dDs = Ds-Ds_n

Further, the corrected concentrated concentration deviation calculating circuit (89)
The concentrated liquid concentration deviation d obtained from the concentrated liquid concentration deviation calculation circuit (88)
From Ds and the condenser abnormality degree Acond obtained from the condenser abnormality degree calculation circuit (87), the concentrated liquid concentration deviation dDs' corrected using the following equation 12 is calculated.

[0039]

DDs' = dDs-k.times.Acond Here, k is a ratio between the degree of abnormality Acon of the condenser shown in FIG.
(For example, 0.01) and is determined experimentally in advance.

The abnormality detecting circuit (80) has a corrected concentrated liquid concentration deviation dD obtained from the corrected concentrated liquid concentration deviation calculating circuit (89).
By comparing s' with a predetermined threshold value, an abnormal signal indicating the degree of abnormalities other than the cooling water contamination is created and output to the display device (9). For example, when dDs ′ <t1, “normal” When t1 ≦ dDs ′ ≦ t2, “slightly abnormal” When dDs ′> t2, it is determined as “abnormal”. Here, t1 and t2 are predetermined thresholds.

According to the above fault diagnosis apparatus, since the concentrated liquid concentration deviation from which the influence of the cooling water contamination is removed can be obtained, accurate failure diagnosis can be performed by using the concentrated liquid concentration deviation as an index.

The description of the above embodiments is for the purpose of illustrating the present invention, and should not be construed as limiting the invention described in the claims or reducing the scope thereof. Further, the configuration of each part of the present invention is not limited to the above-described embodiment, and it is needless to say that various modifications can be made within the technical scope described in the claims. For example, the correction equation for the concentrated concentration deviation is given by Equation 12 above.
However, the present invention is not limited to this, and can be expressed by another linear equation or quadratic equation.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a failure diagnosis device according to the present invention.

FIG. 2 is a graph showing the influence of cooling water contamination included in the concentrated liquid concentration deviation and the effect other than cooling water contamination.

FIG. 3 is a graph showing a relationship between a condenser abnormality degree and a concentrated liquid concentration deviation caused only by cooling water contamination.

FIG. 4 is a graph showing a relationship between a refrigeration load and a concentration of a concentrated liquid.

FIG. 5 is a diagram showing a configuration of an absorption chiller / heater in which the present invention is to be implemented.

[Explanation of symbols]

 (7) Sensor group (8) Arithmetic unit (82) Condenser logarithmic average temperature difference calculation circuit (85) Concentrated liquid concentration estimation circuit (86) Concentrated liquid concentration normal value calculation circuit (87) Condenser abnormal degree calculation circuit (88 ) Concentration deviation calculation circuit (89) Correction concentration deviation calculation circuit (80) Abnormality detection circuit (9) Display

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Shoji Yasuda 2-5-5 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (56) References JP-A-63-297970 (JP, A) JP-A Hei 7-91783 (JP, A) Akiichi Takada, "Absorption Refrigerator", 1st edition, Japan Refrigeration Association, March 15, 1982, p. 252-253 (58) Field surveyed (Int. Cl. ⁷ , DB name) F25B 49/04

Claims (2)

(57) [Claims] 1. An absorption type chiller / heater having a condenser and an absorber, in which an absorption liquid (concentrated liquid) is sprayed toward a cooling water pipe in the absorber, for detecting an abnormality in the concentration of the concentrated liquid. An apparatus for diagnosing a failure by: a temperature measuring means for measuring the temperature of the refrigerant and the cooling water, which performs heat exchange in the condenser; and an average temperature of the refrigerant and the cooling water based on the data measured by the temperature measuring means. Calculating a temperature difference data representing the difference, comparing the temperature difference data with a normal value thereof, and calculating an abnormality degree data indicating an abnormality degree of the condenser; and measuring the concentration of the concentrated liquid. Alternatively, a concentrated liquid concentration deriving means derived by estimation based on measurement data, a concentrated liquid concentration deviation calculating means for calculating a deviation between the derived concentrated liquid concentration and a normal value thereof, and a magnitude of the calculated condenser abnormality degree data The concentrated liquid calculated according to Comprising a concentrated solution concentration deviation correction means for correcting the time difference, modified concentrated liquid fault diagnosis device of an absorption chiller-heater and performing failure diagnosis based on the density difference. 2. The temperature difference data is a log average temperature difference, and the abnormality degree data is an abnormality degree A defined by the following equation 1 using a measured value ΔT and a normal value ΔTn of the log average temperature difference as variables. Item 2. The failure diagnosis device according to Item 1. A = (ΔT−ΔTn) / ΔTn