JP3732893B2 - Control method of absorption chiller / heater - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a control method for an absorption chiller / heater, and more particularly to a control method capable of suppressing temperature fluctuation of a hot fluid taken out from an evaporator.
[0002]
[Prior art]
In order to perform comfortable air conditioning, it is necessary to keep the temperature of the hot fluid taken out from the evaporator constant. For this reason, the rotational speed of the absorption liquid pump is controlled by the frequency calculated based on the temperature of the cooling water supplied to the absorber and the condenser and the temperature of the regenerator, and the temperature fluctuation of the thermal fluid taken out from the evaporator is reduced. Things have been done.
[0003]
[Problems to be solved by the invention]
However, when the capacity control of the absorption chiller / heater is controlled by ON / OFF, by HIGH / LOW / OFF, or when the combustion amount changes suddenly even by proportional control, the intermediate liquid is temporarily removed from the high-temperature regenerator. There is a problem that the temperature of the hot fluid taken out from the evaporator fluctuates greatly.
[0004]
Moreover, the phenomenon that the liquid level rises transiently at the time of start-up occurs, and the absorption liquid pump is temporarily stopped and controlled. This phenomenon has a problem that it frequently occurs in a high-temperature regenerator having a pumping pipe, and this has been a problem to be solved.
[0005]
[Means for Solving the Problems]
The present invention has been made to solve the above-described problems of the prior art, and is connected to an absorber, a condenser, a regenerator, etc. via an absorption liquid pump / refrigerant pump, etc. In an absorption chiller / heater configured to selectively obtain a cold / warm fluid from a heat exchanger built in an evaporator to be formed, and to control the frequency of an absorption liquid pump by an inverter,
[0006]
When the combustion signal of the combustion heating device installed in the regenerator is captured and the combustion amount is increased by 30% or more, the frequency calculated based on the temperature of the cooling water supplied to the absorber and the condenser, the temperature of the regenerator, etc. is predetermined. The frequency calculated based on the temperature of the cooling water, the temperature of the regenerator, etc. when the combustion amount is rapidly reduced by 30% or more is corrected to a frequency smaller than that and larger than the original frequency. A control method of the first configuration in which the rotation is corrected to a frequency larger than that based on a predetermined arithmetic expression and smaller than the original frequency, and the rotation of the absorbent pump is controlled based on the corrected frequency;
[0008]
In the control method of the first configuration, the rotation of the absorbent pump is controlled based on the frequency obtained by correcting the frequency calculated and calculated appropriately until a predetermined time elapses, and the calculation is corrected after the predetermined time elapses. A control method of the second configuration in which the rotation of the absorbing liquid pump is controlled based on the frequency that is not
[0009]
In the control method of the second configuration, a control method of the third configuration in which correction is performed such that the coefficient of the correction arithmetic expression gradually decreases or gradually increases and the correction amount becomes zero in a predetermined time;
By providing the above, the problems of the prior art are solved.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described with reference to the drawings. In the figure, reference numeral 1 is provided with a combustion device 2 such as gas / kerosene, and a high-temperature regenerator that generates a refrigerant vapor by heating a dilute liquid of an absorbing liquid to concentrate it into an intermediate liquid, and 3 is pumped from this regenerator. 4 is a low-temperature regenerator that heats the intermediate liquid with the refrigerant vapor from the gas-liquid separator to make a concentrated liquid, and 5 is from both the regenerators 1 and 4. The condenser 6 cools and condenses the refrigerant vapor, the evaporator 7 scatters and drops the refrigerant liquid from the refrigerant spreader 7A, and evaporates the refrigerant vapor from the low-temperature regenerator 4 An evaporative absorber comprising an absorber 8 that is absorbed in a concentrated liquid to maintain the inside of the vessel at a low pressure, 9 and 10 are low-temperature and high-temperature heat exchangers, 11 is an evaporative absorber 6 and the like using the “flow” of the absorbed liquid as power. An ejector 12 for drawing the gas body is provided below the ejector. A gas-liquid separation chamber 13 for separating the rare liquid and the non-condensable gas stores the non-condensable gas separated in the gas-liquid separation chamber, and discharges the non-condensable gas from the attached palladium cell 14 to the atmosphere. These are the storage chambers, and these are the pumping pipe 21, the intermediate liquid pipe 22, the concentrated liquid pipe 23, the rare liquid pipe 24 having the absorption liquid pump P1, the rare liquid pipes 25 and 26, the refrigerant pipe 27, and the refrigerant liquid pipe 28. , the refrigerant liquid pipe 29 having a refrigerant pump P2, cold / warm switching tube 30 having a cold / warm switching valve V 1, the extraction pipe 31, 32, are connected by a non-condensable gas risers 34, the condenser 5 and evaporative absorber While allowing extraction of non-condensable gas from the vessel 6 to the storage chamber 13, a circulation cycle of refrigerant and absorption liquid is formed, and cold water or hot water selectively taken out from the heat exchanger 41 provided inside the evaporator 7 Either can be circulated and supplied to a heat load (not shown) It has become the jar.
[0011]
Reference numeral 35 denotes a cold / hot water pipe for circulating and supplying cold water cooled by the heat exchanger 41 or heated hot water to a heat load (not shown) such as cooling / heating, with a cold / hot water pump P3 interposed therebetween, A temperature detector 51 for detecting the temperature of the cold / hot water discharged from the evaporator 7 after being cooled or heated is attached.
[0012]
Reference numerals 42 and 43 denote coolers provided inside the condenser 5 and the absorber 8, which are connected by a cooling water pipe 36 having a cooling water pump P 4, so that a cooling tower, the absorber 8 and the condenser (not shown) are connected. The cooling water is configured to circulate between the two. 52 is a temperature detector that is attached to the cooling water pipe and detects the temperature of the cooling water flowing into the absorber 8, and 53 is a temperature detector that is attached to the high temperature regenerator 1 and detects the temperature of the absorbing liquid in the high temperature regenerator. The detector 54 is a liquid level detector that is attached to the gas-liquid separator 3 and detects the liquid level of the absorbing liquid in the gas-liquid separator 3 and 33 is connected to a vacuum pump (not shown). Bleeding pipe, 37 is a pressure equalizing pipe having an on-off valve V2 that is opened during hot water supply operation, 38 is an overflow pipe, 55 is a rare liquid damper, 56 is an intermediate liquid damper, 57 is a refrigerant liquid damper, and 100 is a controller of this apparatus. It is.
[0013]
In the cold / warm switching type absorption chiller / heater having the above-described configuration, the refrigerant refrigeration in the heat exchanger 41 of the evaporator 7 is performed by performing an absorption refrigeration cycle by circulating the refrigerant and the absorption liquid during the cooling operation performed by taking out the chilled water. The water in the heat exchanger can be cooled to about 6-8 ° C. and supplied by latent heat of vaporization, while the supply of the cooling water to the coolers 41 and 43 is stopped during the heating operation performed by taking out the hot water. By switching the cold / warm switching valve V1 from closed to open, the high-temperature absorption liquid and the refrigerant vapor flow from the gas-liquid separator 3 to the evaporation absorber 6 via the cold / warm switching pipe 30, and the heat exchanger Hot water heated by the latent heat of condensation of the refrigerant at 41 (or this heat and the sensible heat of the absorbing liquid) is supplied.
[0014]
In the above operation, the controller 100 controls the combustion of the combustion device 2 by calculating and calculating a required combustion amount based on the difference between the temperature detected by the temperature detector 51 and a preset temperature or the rate of change thereof. . Further, the absorption liquid pump P1 is controlled to be ON / OFF based on the level of the absorption liquid detected by the liquid level detector 54 to maintain the liquid level of the absorption liquid within a predetermined range, and the rotation speed during operation is set to the temperature. Control is performed based on the temperature detected by the detectors 52 and 53.
[0015]
That is, the frequency of the electric power supplied to the motor M1 that drives the absorption liquid pump P1 is based on the temperature of the cooling water detected by the temperature detector 52 and the temperature of the absorption liquid of the high-temperature regenerator 1 detected by the temperature detector 53. For example, the calculation is performed from the relational expression in FIG.
[0016]
Then, when varying more than 30% than the combustion amount of up to Re combustion amount pixels of the combustion device 2, it is based on the temperature at which the temperature detector 52, 53 is detected when the change in the direction of increasing relation 2 From the frequency obtained by calculating from the relational expression of FIG. 2 based on the temperature detected by the temperature detectors 52 and 53 when the combustion amount changes in the direction of decreasing. Correct in the increasing direction.
[0017]
This correction may be performed in the same manner over a predetermined time, for example, 1 minute, or may be performed so that the correction after the predetermined time becomes zero.
[0018]
FIG. 3 shows a correction at a predetermined rate over a predetermined time (in this case, 1 minute). When a control signal for rapidly reducing the combustion amount is output to the combustion device 2, the correction coefficient is applied over the predetermined time. Is fixed to 1.2, and when a control signal for rapidly increasing the combustion amount is output to the combustion apparatus 2, the correction coefficient is fixed to 0.8 over a predetermined time.
[0019]
That is , when the control signal for suddenly decreasing the cooling / heating load and reducing the combustion amount of the combustion device 2 by 30% or more is output to the combustion device 2, the temperature detectors 52 and 53 are set at predetermined time intervals (for example, 5 seconds). Electric power having a frequency obtained by multiplying a frequency obtained by calculating from the relational expression of FIG. 2 based on the detected temperature by 1.2 is supplied to the motor M1, and the rotational speed of the absorbent pump P1 is set to a predetermined time (in this case, 1 minute). When the control signal for rapidly increasing the cooling / heating load and increasing the combustion amount of the combustion device 2 by 30% or more is output to the combustion device 2, the temperature is detected every predetermined time (for example, 5 seconds). 2 is supplied to the motor M1 at a frequency obtained by multiplying the frequency obtained by calculating from the relational expression of FIG. 2 based on the temperature detected by the chambers 52 and 53 to the motor M1, and the rotational speed of the absorbent pump P1 is set for a predetermined time. (In this case 1 minute) control
[0020]
Therefore, when the combustion amount of the combustion device 2 rapidly decreases, the bubbles heated by the combustion device 2 and rising in the pumped liquid pipe 21 together with the absorbing liquid disappear or rapidly decrease. However, when the amount of combustion is suddenly reduced, the amount of circulation of the absorbent by the absorbent pump P1 is limited to a predetermined time. Since the liquid level of the absorption liquid in the gas-liquid separator 3 is prevented from abruptly decreasing and the amount of combustion in the combustion device 2 increases rapidly, the combustion device 2 is heated and rises in the lift pipe 21. Since bubbles are generated or suddenly increase in the absorbed liquid, the sudden increase in the amount of combustion leads to an increase in the liquid level of the absorbent liquid in the pumping pipe 21 and the absorption liquid pump P1 is stopped due to the liquid level in the gas-liquid separator 3. It is easy to cause, but absorbs when the amount of combustion increases rapidly Since the circulation amount of the absorption liquid by the pump P1 is reduced for a predetermined time, the rapid rise of the liquid level of the absorbing liquid in the gas-liquid separator 3 is prevented.
[0021]
That is, by controlling the rotational speed of the absorbent pump P1 when the combustion amount of the combustion device 2 changes greatly as described above, fluctuations in the absorbent circulation are suppressed, thereby reducing the fluctuation range of the refrigerating capacity. And comfortable cooling / heating can be realized.
[0022]
Further, the correction coefficient may be gradually decreased or increased, and may be changed as shown in FIG. 4 so that the correction amount becomes zero in a predetermined time (for example, 1 minute).
[0023]
By controlling the rotational speed of the absorption liquid pump P1 in this way, fluctuations in the absorption liquid circulation are further suppressed, so that more comfortable cooling / heating can be realized.
[0024]
Further, as a correction of the power frequency supplied to the motor M1, a constant may be simply added or subtracted. That is, when the cooling / heating load is suddenly reduced and the combustion amount of the combustion apparatus 2 is suddenly reduced by, for example, 30% or more, the calculation is performed from the relational expression of FIG. 2 based on the temperature detected by the temperature detectors 52 and 53 every predetermined time. The motor M1 is supplied with electric power having a frequency obtained by adding a predetermined number, for example, 5% of the rated frequency, to the frequency obtained in this manner, and the number of revolutions of the absorbing liquid pump P1 is controlled over a predetermined time, thereby rapidly increasing the cooling / heating load. When the combustion amount of the combustion apparatus 2 is rapidly increased by, for example, 30% or more, a predetermined number, for example, a rated frequency is obtained by calculating from the relational expression of FIG. 2 based on the temperature detected by the temperature detectors 52 and 53 every predetermined time. A frequency obtained by subtracting 5% of the frequency may be supplied to the motor M1, and the rotational speed of the absorbing liquid pump P1 may be controlled over a predetermined time.
[0025]
That is, the correction coefficient referred to in the present invention includes not only a coefficient as a multiplier but also a constant to be added and a constant to be subtracted.
[0026]
The constant to be added or subtracted may be gradually reduced or gradually increased so that the correction amount becomes zero in a predetermined time (for example, 1 minute).
[0027]
The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit described in the claims.
[0028]
For example, when the correction coefficient is gradually decreased or gradually increased, it may be changed as a linear function or a cubic function in addition to being changed as a linear function of time.
[0029]
Further, a temperature detector 51A is provided instead of the temperature detector 51, and based on a difference between the temperature of cold / warm water returning to the evaporator 7 detected by the temperature detector 51A and a preset temperature, or a rate of change thereof. Thus, the present invention can also be applied to an absorption chiller / heater of the type that controls the combustion amount of the combustion device 2.
[0030]
Moreover, the basic frequency of the electric power supplied to the motor M1 that drives the absorbing liquid pump P1 is also applied based on only the absorbing liquid temperature of the high-temperature regenerator 1 detected by the temperature detector 53. it can.
[0031]
Moreover, an absorption chiller / heater having a structure that does not include the gas-liquid separator 3 may be used, or an absorption chiller / heater that integrates the gas-liquid separator 12 and the storage chamber 13 may be applied.
[0032]
【The invention's effect】
As described above, according to the control method of the present invention, fluctuations in the circulation of the absorbing liquid are suppressed, so that the fluctuation range of the refrigerating capacity is reduced and comfortable cooling / heating can be realized. In particular, in the control method according to claim 3 in which the correction coefficient is gradually increased or decreased, fluctuations in the absorption liquid circulation are further suppressed, so that more comfortable cooling / heating can be realized.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram illustrating an example of a device configuration.
FIG. 2 is a relational diagram for obtaining a fundamental frequency for driving an absorbing liquid pump.
FIG. 3 is an explanatory diagram showing a first setting procedure for correction coefficients;
FIG. 4 is an explanatory diagram showing a second setting procedure of correction coefficients.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 High temperature regenerator 2 Combustion apparatus 3 Gas-liquid separator 4 Low temperature regenerator 5 Condenser 6 Evaporation absorber 7 Evaporator 7A Refrigerant spreader 8 Absorber 8A Absorbent liquid spreader 9 Low temperature heat exchanger 10 High temperature heat exchanger 11 Ejector 12 Gas-liquid separation chamber 13 Storage chamber 14 Palladium cell 21 Lifting pipe 22 Intermediate liquid pipe 23 Concentrated liquid pipe 24 Diluted liquid pipe 25-26 Diluted liquid pipe 27 Refrigerant pipe 28/29 Refrigerant liquid pipe 30 Cold / warm switching pipe 31- 33 Extraction pipe 34 Non-condensable gas rise pipe 35 Cold / hot water pipe 36 Cooling water pipe 37 Pressure equalizing pipe 38 Overflow pipe 41 Heat exchanger 42/43 Cooler 51 / 51A / 52/53 Temperature detector 54 Liquid level detector 55 Diluted liquid Damper 56 Intermediate liquid damper 57 Refrigerant liquid damper 100 Controller M1 Motor P1 Absorbing liquid pump P2 Refrigerant pump P3 Cold / hot water pump P4 Cooling water pump P5 Second absorbing liquid pump V1 Cooling / warming Kawaben

Claims (3)

Cooling / heating fluid is connected to the absorber / condenser / regenerator etc. via the absorption liquid pump / refrigerant pump, etc., and either the cold / warm fluid from the heat exchanger built in the evaporator forming the circulation cycle of refrigerant and absorption liquid. In an absorption chiller / heater whose frequency is controlled by an inverter with an absorption liquid pump, the combustion signal of the combustion heating device installed in the regenerator is captured and absorbed when the combustion amount is rapidly increased by 30% or more. The frequency calculated based on the temperature of the cooling water supplied to the condenser and condenser, the temperature of the regenerator, etc. is corrected to a frequency that is smaller than that based on the prescribed formula and larger than the original frequency, and the amount of combustion When the frequency is rapidly decreased by 30% or more, the frequency calculated based on the cooling water temperature, the regenerator temperature, etc., is larger than that based on a predetermined arithmetic expression, and is the original frequency. Small frequency correction, the control method of the absorption chiller, characterized by controlling the rotation of the absorbent pump based on the frequency that the correction is. Until the predetermined time elapses, the rotation of the absorbent pump is controlled based on the frequency obtained by appropriately correcting the frequency calculated and calculated. After the predetermined time has elapsed, the rotation of the absorbent pump is performed based on the frequency that is calculated and not corrected. the method of claim 1 Symbol placement and controls the. The control method according to claim 2 , wherein correction is performed such that a coefficient of the correction formula gradually decreases or gradually increases and the correction amount becomes zero in a predetermined time.

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