JPH0829028A - Abnormal state sensing device of absorptive cold and hot water machine - Google Patents

Abstract

PURPOSE:To detect an abnormal state in an absorbing device under a simple configuration in an absorptive cold and hot water machine having an evaporator and an absorbing device and the like. CONSTITUTION:An abnormal state sensing device is comprised of a group of sensors 7 for measuring a representing temperature at one position or at a plurality of positions in regard to cooling water and absorption liquid related to a heat exchanging operation at an absorbing device. Measured, data obtained from the group of sensors 7 is supplied to a calculator 8. The calculator 8 is comprised of a circuit 81 for calculating an actual difference of average temperatures under utilization of an easy calculation equation defined by the four rules of arithmetic calculation, a circuit 82 for calculating a heat exchanging amount at the absorbing device, and a circuit 84 for comparing an actual difference in average temperatures with a rational average temperature difference under the same heat exchanging amount in response to a heat exchanging amount obtained from the circuit and calculating a degree of abnormal state in the absorbing device.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an absorption chiller / heater,
In particular, the present invention relates to an abnormality detection device that detects an abnormality of the absorber.

[0002]

2. Description of the Related Art An absorption chiller-heater, as shown in FIG. 4, has a condenser (11) and a low temperature regenerator (12) arranged on an upper body (1), and an evaporator arranged on a lower body (2). Vessel (21) and absorber (22), burner
High temperature regenerator (3) with built-in (31), high temperature heat exchanger (4), low temperature heat exchanger (5) etc.
By (6), the absorption liquid is absorbed by the high temperature regenerator (3) and the low temperature regenerator (1).
It is circulated between 2) and the absorber (22) to realize a refrigeration cycle or a heat radiation cycle. The cooling water pipe that passes through the evaporator (21) and the condenser (11) has a cooling tower.
Cooling water from (not shown) flows.

By the way, in the absorption chiller-heater, various abnormalities such as contamination of cooling water, abnormal amount of absorbed liquid circulation, abnormal vacuum degree, mixing of absorbing liquid with refrigerant (mixing of refrigerant), etc. may occur. There is When the cooling water becomes dirty, foreign matter such as dust adheres to the inner surface of the cooling water pipe, reducing the heat transfer coefficient, and
Since the cooling effect in (11) and the absorber (22) becomes insufficient, the refrigerating capacity decreases. If the absorbing liquid mixes with the refrigerant,
The boiling point of the refrigerant rises, and as a result, the temperature inside the lower body (2) rises, resulting in deterioration of the capabilities of the evaporator (21) and the absorber (22). Also, when the vacuum level of the lower body (2) drops, the evaporator (21)
And the capacity of the absorber (22) will be reduced.

Therefore, in order to diagnose various abnormalities inside the chiller / heater, various changes in the logarithmic mean temperature difference of various heat exchangers such as the evaporator (21), the absorber (22), and the condenser (11) are monitored. (March 11, 1994, The Japan Society of Mechanical Engineers RC123
See pages 77-82). A temperature sensor such as a thermocouple or thermistor is attached to the inlet / outlet of each heat exchanger in order to measure the fluid temperature at the inlet / outlet of each heat exchanger.

Further, the applicant has proposed a method of diagnosing various failures based on the abnormality degree defined by the following degree 2 as an index showing the degree of abnormality of each part of the chiller heater. are doing.

[0006]

## EQU00002 ## A = (. DELTA.T-.DELTA.Tn) /. DELTA.Tn Here, .DELTA.T is an actual logarithmic average temperature difference (measured value) based on measurement, and .DELTA.Tn is an ideal logarithmic average temperature difference (normal value).

[0007]

However, in order to calculate the logarithmic mean temperature difference and the degree of abnormality, 3 to 4 temperature sensors are required for one heat exchanger, and particularly in the absorption type chiller-heater. , If all the heat exchangers are equipped with the necessary temperature sensors, then a total number of temperature sensors must be equipped. However, in calculating the logarithmic average temperature difference, a special program or memory for logarithmic calculation is required, which causes a problem that the circuit scale becomes large. An object of the present invention is to provide an abnormality detection device for an absorption chiller-heater which can detect an abnormality in the absorber with a simple structure.

[0008]

An abnormality detecting device for an absorption chiller-heater according to the present invention has a representative temperature at one or a plurality of positions for cooling water and absorbing liquid involved in heat exchange in the absorber. And a calculation formula of temperature difference data defined by the four arithmetic operations of the representative temperature are stored, and the actual temperature difference data is calculated from the measurement data by the temperature measurement device using the calculation formula. Temperature difference data calculation means, heat exchange amount in the absorber, or heat exchange amount deriving means for deriving the other heat exchange amount that changes according to the heat exchange amount by measurement and calculation, and ideal in normal operation Based on the heat exchange amount obtained from the ideal temperature difference data storage means in which the temperature difference data of is stored in relation to the heat exchange amount and the heat exchange amount deriving means, the actual difference obtained from the temperature difference data calculation means temperature The data was compared with the ideal temperature difference data in the same heat exchange amount, which comprises an abnormality determination means for creating abnormal data representing the abnormality of the absorber.

In a specific configuration, the heat exchange amount derivation means is composed of temperature sensors (71) and (72) for measuring the temperature of cooling water at the inlet and outlet of the absorber, and a flow rate sensor for measuring the flow rate of the cooling water. (75), and arithmetic means for calculating the heat exchange amount of the absorber based on the measurement data of these sensors.

In another specific configuration, the heat exchange amount derivation means includes temperature sensors (76) (77) for measuring the temperature of cold water at the inlet and outlet of the evaporator, and a flow rate sensor for measuring the flow rate of the cold water. (78) and arithmetic means for calculating the heat exchange amount of the evaporator based on the measurement data of these sensors.

Further, in the concrete configuration, the abnormality determining means is configured such that the actual temperature difference data ΔT and the ideal temperature difference data ΔTn.
Is used as a variable to calculate the degree of abnormality A defined by the above equation 2,
This is output as abnormal data.

[0012]

In the above-described abnormality detecting device, temperature difference data defined by simple four arithmetic expressions are used as an index for evaluating abnormality of the absorber, instead of the conventional logarithmic average temperature difference. The temperature difference data may be, for example, the difference between the inlet temperature Ta_in of the absorbing liquid (concentrated liquid) dispersed in the absorber and the outlet temperature Tco_out of the cooling water flowing out from the absorber.
(Ta_in-Tco_out) can be defined.

By the way, when the heat exchange performance of the heat exchanger is absolutely evaluated, the logarithmic mean temperature difference is a suitable evaluation index.
It is appropriate to perform a relative evaluation by comparing the logarithmic mean temperature difference of each heat exchanger with the value during normal operation. In this case, the significance of the absolute value of the logarithmic average temperature difference is low.

On the other hand, like the above-mentioned temperature difference data, the temperature difference data defined by the four arithmetic operations of the representative temperatures of the cooling water and the absorbing liquid in the absorber are not necessarily highly significant as absolute values. It can be an appropriate index when performing relative evaluation for the purpose of failure diagnosis of the absorption chiller-heater.

Therefore, in the present invention, paying attention to this point, the representative temperatures of the cooling water and the absorbing liquid in the absorber are measured, and the temperature difference data is calculated based on the measured data. And
The temperature difference data is compared with the ideal temperature difference data at the same heat exchange amount to calculate the abnormal data. The abnormality data represents the degree of abnormality relative to normal operation.

Here, it is necessary to compare the actual temperature difference data and the ideal temperature data with the same heat exchange amount. In the specific configuration of the present invention, the inlet / outlet temperature difference of the cooling water in the absorber and the cooling water flow rate are compared. The heat exchange amount in the absorber is calculated by multiplying by.

In another specific configuration, the heat exchange amount of the evaporator, that is, the refrigerating load is calculated by multiplying the cold water inlet / outlet temperature difference in the evaporator by the cold water flow rate. Since the heat exchange amount in the absorber and the heat exchange amount in the evaporator are in proportion to each other, it is possible to use any heat exchange amount as a reference when calculating the abnormal data.

As the abnormality data, the above-mentioned abnormality degree A proposed by the applicant can be adopted. In this case, the abnormality degree is calculated according to the load even when the load is low, and the abnormality can be determined based on the abnormality degree. Therefore, for example, in preparation for a heavy load such as summer, maintenance and inspection of the chiller-heater can be performed early to avoid operation stoppage at a high load.

[0019]

According to the abnormality detecting apparatus for the absorption chiller-heater according to the present invention, the temperature difference data is defined by a simple arithmetic operation instead of the conventional logarithmic mean temperature difference. The measurement of the representative temperature, which is the basis of the above, can be performed at two or three points, which reduces the number of temperature sensors as compared with the conventional case. Of course, the temperature difference data can be calculated only by the four arithmetic operations, and the conventional logarithmic calculation is not required. Therefore, the circuit scale is reduced and the overall configuration is simplified.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An example in which the present invention is applied to a double-effect absorption-type chiller-heater shown in FIG. 4 will be described in detail below with reference to the drawings. The absorption chiller-heater uses water as a refrigerant and lithium bromide as an absorbing liquid, and when supplying chilled water, a high temperature regenerator is used.
The refrigerant evaporated in (3) passes through the low temperature regenerator (12) and then the condenser (1
It flows to 1), exchanges heat with the cooling water flowing in the condenser 11 to condense and liquefy, and then flows to the evaporator 21. The liquefied refrigerant exchanges heat with the cold water flowing in the evaporator (21) to evaporate, and the heat of vaporization at that time cools the cold water flowing in the evaporator (21).

The refrigerant evaporated in the evaporator (21) absorbs the refrigerant (22)
Is absorbed by the absorbent. The absorption liquid, which has become thinner due to absorption of the refrigerant, is cooled by the 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).
The refrigerant is heated by the evaporation of the refrigerant, and the medium-concentration absorption 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 absorbing solution having a high concentration is sent to the absorber (22) through the low temperature heat exchanger (5) and is scattered.

The pipes connected to the heat exchangers such as the absorber (22), the evaporator (21), the condenser (11), and the like, in order to measure the temperature and flow rate of fluids involved in heat exchange, Cooling water inlet temperature sensor (71), cooling water intermediate temperature sensor (72), absorbing liquid inlet temperature sensor (73), absorbing liquid outlet temperature sensor (74), cold water inlet temperature sensor (76), cold water outlet temperature sensor (77 ), Condensed refrigerant temperature sensor (79), cooling water outlet temperature sensor (70)
A sensor group consisting of etc. is provided.

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

The arithmetic unit (8) comprises calculation circuits (81), (82), (83) and (84) and a failure judgment circuit (85), which will be described later, each of which is composed of a computer program. The absorber average temperature difference calculation circuit (81) includes a cooling water inlet temperature Tco_in obtained from the cooling water inlet temperature sensor (71) and a cooling water intermediate temperature Tco_mid obtained from the cooling water intermediate temperature sensor (72).
And the absorption liquid obtained from the absorption liquid inlet temperature sensor (73)
(Concentrated liquid) inlet temperature Ta_in and absorption liquid outlet temperature sensor
From the absorption liquid (rare liquid) outlet temperature Ta_out obtained from (74), the average temperature difference Tm of the absorber (22) is calculated by the following mathematical expression 3.

[0025]

## EQU00003 ## Tm = {(Ta_in + Ta_out)-(Tco_in + Tco_mid)} / 2 The average temperature difference Tm calculated by the above Equation 3 is the absorber.
It represents the difference between the average temperature of the absorbing liquid flowing in (22) and the average temperature of the cooling water, and the logarithmic average temperature difference of the absorber (22) is an approximate value.

Here, the average temperature difference Tm of the absorber (22) is not limited to the formula defined by the formula 3, but various values defined by the formulas shown in the following formula 4 may be adopted. It is possible.

[0027]

## EQU00004 ## Tm = Ta_in- (Tco_in + Tco_mid) / 2 Tm = Ta_out- (Tco_in + Tco_mid) / 2 Tm = (Ta_in + Ta_out) / 2-Tco_in Tm = (Ta_in + Ta_out) / 2-Tco_ain_out-Tm = Tm. Tm = Ta_out-Tco_mid Tm = Ta_in-Tco_mid

The absorber heat exchange amount calculation circuit (82) has a cooling water inlet temperature Tco obtained from the cooling water inlet temperature sensor (71).
_In, the cooling water intermediate temperature Tco_mid obtained from the cooling water intermediate temperature sensor (72), and the cooling water flow rate sensor (7
From the cooling water flow rate Vco obtained from 5), the heat exchange amount Qabs of the absorber (22) is calculated by the following equation 5.

[0029]

## EQU00005 ## Qabs = Vco.times. (Tco_mid-Tco_in)

The refrigeration load calculation circuit (83) includes a cold water inlet temperature Tc_in obtained from the cold water inlet temperature sensor (76) and a cold water outlet temperature Tc obtained from the cold water outlet temperature sensor (77).
From _out and the cold water flow rate Vc obtained from the cold water flow rate sensor (78), the heat exchange amount of the evaporator (21) is calculated by the following equation 6.
That is, the refrigeration load Lc is calculated.

[0031]

[Equation 6] Lc = Vc × (Tc_in−Tc_out)

The absorber abnormality degree calculating circuit (84) is obtained from the absorber average temperature difference Tm obtained from the absorber average temperature difference calculating circuit (81) and the absorber heat exchange amount calculating circuit (82). The abnormality degree Aabs of the absorber (22) is calculated by the following equation 7 based on the absorber heat exchange amount Qabs.

[0033]

## EQU00007 ## Aabs = (Tm-Tmn) / Tmn

Here, Tmn is an ideal average temperature difference at the time of normal operation, and the absorber heat exchange amount Qabs is previously set.
Is stored in the memory in the form of a graph or a table.

In FIG. 2, the abscissa indicates the heat exchange amount of the absorber, and the ordinate indicates the average temperature difference. The change a of the ideal average temperature difference Tmn and the average temperature difference obtained based on the actual measurement are shown. Tm
3 is a graph showing the change b of The abnormality degree Aabs defined by the above equation 7 is a value obtained by normalizing the difference between the actual average temperature difference Tm and the ideal average temperature difference Tmn in the arbitrary heat exchange amount shown in FIG. 2 by the ideal average temperature difference Tmn. , It is a universal index that indicates the degree of abnormality of the absorber regardless of the amount of heat exchange.

The amount of heat exchange to be used as a reference when calculating the degree of abnormality of the absorber (22) is not limited to the amount of heat exchange of the absorber (22), but is also proportional to this. It is also possible to adopt the heat exchange amount of the vessel (21), that is, the refrigeration load. In this case, the refrigeration load Lc obtained from the refrigeration load calculation circuit (83) shown in FIG. 1 is supplied to the absorber abnormality degree calculation circuit (84),
It is used to calculate the degree of abnormality.

The failure determination circuit (85) compares the absorber abnormality degree obtained from the absorber abnormality degree calculation circuit (84) with a predetermined evaluation standard to determine the degree of failure and displays the result.
It is output to (9).

When the average temperature difference of the above equation 3 is adopted in the above abnormality detecting device, the same level of reliability as that of the conventional abnormality detection due to the logarithmic average temperature difference is maintained by a simple calculation that does not require logarithmic calculation. As it is, the abnormality of the absorber can be detected and the failure can be determined. Here, when comparing the failure determination based on the average temperature difference according to the simple calculation formula of the present invention and the conventional failure determination based on the logarithmic average temperature difference, any failure determination is determined by the absolute value of the temperature difference. Relative ratio based on normal temperature difference
Since the judgment is made based on the (abnormality), it is meaningless to perform logarithmic calculation, and it can be said that both judgments have no superiority or inferiority.

As described above, in the present invention, since a simple calculation formula that does not require logarithmic calculation is adopted, the circuit scale becomes smaller than the conventional one, and when mounting the circuit board on the control panel of the water chiller / heater. It is advantageous.

Further, when the average temperature difference of the above equation 4 is adopted, the required temperature measurement is reduced from the conventional 4 points to 3 points or 2 points. Therefore, the temperature sensor to be installed in the absorption chiller / heater. The number is reduced and the configuration becomes simple.

Although the above-mentioned abnormality detecting device is intended for the absorber (22), the abnormality can be detected for the condenser (11) in the same manner. FIG. 3 shows the configuration of the abnormality detecting device for the condenser (11), and similarly to the above, the measurement data from the sensor group (7) is supplied to the arithmetic device (80), and the condenser (11) Failure determination is performed based on the abnormality detection, and the result is displayed on the display device (9).

The arithmetic unit (80) includes a circuit (86) for calculating the average temperature difference of the condenser and a circuit (8) for calculating the heat exchange amount of the condenser.
7), a circuit (88) for calculating the degree of abnormality of the condenser, and a failure determination circuit (89). Condenser average temperature difference calculation circuit (8
In 6), the cooling water intermediate temperature Tco_mid obtained from the cooling water intermediate temperature sensor (72) and the cooling water outlet temperature sensor
Cooling water outlet temperature Tco_out obtained from (70) and condensed refrigerant temperature Tv obtained from condensed refrigerant temperature sensor (79)
From _cond, the average temperature difference Tm ′ of the condenser is calculated by the calculation formula shown in Expression 8 below.

[0043]

## EQU00008 ## Tm '= {(Tv_cond-Tco_mid) + (Tv_cond-Tco_out)} / 2

As the average temperature difference of the condenser, it is possible to adopt a simpler calculation formula defined by the measurement data of 2 points. Further, if the circuit scale is not a problem, the conventional logarithmic average temperature difference may be adopted.

In the condenser heat exchange amount calculation circuit (87), the cooling water intermediate temperature Tc obtained from the cooling water intermediate temperature sensor (72) is obtained.
The condenser heat exchange amount Qcond is calculated by the following equation 9 from o_mid, the cooling water outlet temperature Tco_out obtained from the cooling water outlet temperature sensor (70), and the cooling water flow rate Vco obtained from the cooling water flow rate sensor (75). It

[0046]

## EQU00009 ## Qcond = Vco.times. (Tco_out-Tco_mid)

The condenser abnormality degree calculation circuit (88) obtains the actual condenser average temperature difference Tm 'obtained from the condenser average temperature difference calculation circuit (86) and the condenser heat exchange amount calculation circuit (87). The abnormality degree Acond of the condenser (11) is calculated by the following equation 10 based on the generated condenser heat exchange amount Qcond.

[0048]

## EQU10 ## Acond = (Tm'-Tmn ') / Tmn'

Here, Tmn 'is an ideal average temperature difference during normal operation, and the heat exchange amount Qco of the condenser is previously set.
It is stored in the memory after being graphed or tabulated in relation to nd.

The condenser abnormality degree obtained from the condenser abnormality degree calculation circuit (88) is supplied to the failure determination circuit (89) and compared with a predetermined evaluation standard. Then, the failure judgment circuit (89) judges the degree of failure based on the comparison result, and outputs the result to the display device (9).

According to the abnormality detecting device for the condenser shown in FIG. 3, not only the abnormality of the condenser can be accurately detected and the maintenance and inspection can be performed early even when the chiller-heater has a partial load. In terms of circuit configuration, the same effect as that of the abnormality detecting device for the absorber shown in FIG. 1 can be obtained.

The above description of the embodiments is for explaining the present invention, and should not be construed as limiting the invention described in the claims or reducing the scope. The configuration of each part of the present invention is not limited to the above-mentioned embodiment, and it goes without saying that various modifications can be made within the technical scope described in the claims.

For example, in the above embodiment, the flow rate of the cooling water or the cooling water is actually measured when the heat exchange amount of the condenser (11) and the absorber (22) or the evaporator (21) is calculated. In the case of a constant flow rate, it is possible to derive the heat exchange amount by calculation based on only the measured data of the cooling water or the inlet / outlet temperature of the cold water.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an abnormality detection device according to the present invention.

FIG. 2 is a graph showing changes in average temperature difference with respect to heat exchange amount.

FIG. 3 is a block diagram showing a configuration of an abnormality detection device for a condenser.

FIG. 4 is a diagram showing a configuration of an absorption chiller-heater in which the present invention is implemented.

[Explanation of symbols]

 (71) Cooling water inlet temperature sensor (72) Cooling water intermediate temperature sensor (73) Absorbing liquid inlet temperature sensor (74) Absorbing liquid outlet temperature sensor (8) Computing device (9) Display device

Claims (4)

[Claims] 1. In an abnormality detection device for an absorption chiller-heater equipped with an evaporator, an absorber, etc., a representative of cooling water and absorbing liquid involved in heat exchange in the absorber at one or a plurality of positions, respectively. Temperature measurement means for measuring temperature, a calculation formula of temperature difference data defined by the four arithmetic operations of the representative temperature is stored, and using the calculation formula, actual temperature difference data is obtained from the measurement data by the temperature measurement device. A temperature difference data calculating means for calculating, a heat exchange amount in the absorber, or a heat exchange amount deriving means for deriving another heat exchange amount that changes depending on the heat exchange amount, by a heat exchange amount deriving means during normal operation. The ideal temperature difference data, ideal temperature difference data storage means stored in relation to the heat exchange amount, based on the heat exchange amount obtained from the heat exchange amount derivation means,
The temperature difference data calculation means compares the actual temperature difference data with the ideal temperature difference data at the same heat exchange amount, and an abnormality determination means for generating abnormality data indicating an abnormality of the absorber is provided. Abnormality detection device for absorption type water heaters and heaters. 2. The heat exchange amount derivation means is a temperature sensor (71) (72) for measuring the temperature of cooling water at the inlet and outlet of the absorber.
The abnormality detection according to claim 1, further comprising: a flow rate sensor (75) for measuring the flow rate of the cooling water; and a calculation means for calculating the heat exchange amount of the absorber based on the measurement data of these sensors. apparatus. 3. The heat exchange amount derivation means is a temperature sensor (76) (77) for measuring the temperature of cold water at the inlet and outlet of the evaporator.
The abnormality detection device according to claim 1, further comprising: a flow rate sensor (78) for measuring the flow rate of the cold water; and a calculation means for calculating the heat exchange amount of the evaporator based on the measurement data of these sensors. . 4. The abnormality determination means is used for the actual temperature difference data T.
The abnormality detection device according to claim 1, wherein the abnormality degree A defined by the following equation 1 is calculated using m and the ideal temperature difference data Tmn as variables, and this is output as abnormality data. ## EQU1 ## A = (Tm-Tmn) / Tmn