JP3126884B2 - Air conditioner using absorption refrigerator - Google Patents

Abstract

PURPOSE: To suitably perform control conformed to a target as much as possible suppressing generation of overshoot and undershoot by performing an integral calculation when a temperature of a condenser changes in a direction, in which a calculated capacity of an air cooling fan actually comes within a range of a possible capacity of the air cooling fan. CONSTITUTION: When an actual outside air temperature significantly exceeds an assumed outside air temperature, it is desired to increase a cooling capacity, and a control output beyond a capacity of an air cooling fan 17 is sometimes fed to the fan 17. However, the air cooling fan 17 cannot rotate beyond its capacity but acts at its critical capacity in spite of an output from arithmetic means, and an integral calculation of deviation by the arithmetic means is simultaneously stopped. When a period of time elapses and a temperature of a condenser 16 decreases, its temperature changes in a direction, in which a capacity of the air cooling fan is caused to decrease, so that control means dictates start-up of integral calculation of deviation even when a calculated value for the capacity of the air cooling fan 17 exceeds that of an actual capacity of the air cooling fan 17.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner using an absorption refrigerator for general houses and small buildings.

[0002]

2. Description of the Related Art Air conditioners using absorption chillers are currently used for industrial applications such as factories, buildings or large stores.
It is mainly used for commercial facilities.

In a cooling system of an air conditioner using an absorption refrigerator, a refrigerant vapor evaporated in a regenerator is condensed in a water-cooled condenser, and the condensed refrigerant is guided to an evaporator to evaporate. The cooling medium (usually water) circulating between the fan coil unit provided in the room to be cooled by the latent heat of evaporation and the refrigerator is cooled. On the other hand, the operation is performed in a cycle in which the evaporated refrigerant vapor is absorbed into a concentrated solution (absorbing liquid) by a water-cooled absorber and returned to the regenerator again.

In an air conditioner using an absorption type refrigerator of this type, the temperature of a cooling medium circulated in an indoor fan coil unit is cooled to about 7 ° C. in an evaporator, and the cooling medium is cooled in a fan coil in the room. To cool the room air and return it to the evaporator at around 12 ° C. When an aqueous solution of lithium bromide is used as the absorbing solution, it is necessary to maintain the temperature of the absorbing solution in the absorber at around 40 ° C. In order to maintain this temperature, a cooling tower is installed on a rooftop or the like to provide a water cooling circuit. Cooling method is adopted.

[0005] However, the conventional air-conditioning apparatus using a water-cooled absorption chiller has the following problems.

(1) Since the temperature of the absorber is controlled by a water-cooling method, the equipment becomes large and piping is required, which requires a lot of construction cost, and is necessary for general houses and small-scale buildings. Not suitable for cooling.

(2) Since it is necessary to connect the fan coil unit in the room to be cooled and the refrigerator with a pipe for circulating cooling medium, construction costs and equipment costs are high. This is the same for an ammonia absorption refrigerator using ammonia water as the absorbing liquid and the refrigerant.

Therefore, the present inventors perform a cooling cycle operation in which the condenser and the absorber are cooled not by the water cooling system but by the air cooling system, and the air to be cooled is directly passed through the evaporator to be cooled instead of using the cooling medium. Proposing an air conditioner (Japanese Patent Application No. Hei 5)
-22351).

FIG. 5 shows a main part of a modification of an air conditioner using a single-effect absorption refrigerator proposed in the above-mentioned application, and FIG. 6 shows an installation state of the air conditioner.

[0010] As shown in FIG.
The outdoor unit 1 is disposed outside the room 5 of the house to be air-conditioned by a configuration as shown in FIG. 5, and the indoor unit 2 has only the cool air outlet and the indoor air inlet. And is disposed inside the chamber 5. The outdoor unit 1 and the indoor unit 2 are connected by a cooling air blow duct 3 and a room air intake duct 4. Reference numeral 6 denotes a remote controller for starting or stopping the operation of the apparatus, setting or canceling the automatic operation, setting the room temperature, and adjusting the amount of blown cold air.

The interior of the outdoor unit 1 is configured as shown in FIG. 5, in which an aqueous solution of lithium bromide is used as an absorbing liquid and water is used as a refrigerant.

The evaporator 10 has a function of evaporating the refrigerant and cooling the air passing therethrough by the latent heat of evaporation.
The air duct 3 and the intake duct 4 are connected. A blower fan 11 is provided in the intake duct 4.

The regenerator 12 has a function of generating refrigerant vapor by heating the absorption liquid having a low concentration by absorbing the refrigerant by the burner 13 and concentrating the absorption liquid. Fuel gas is supplied to the burner 13 from a fuel supply pipe 14, and the degree of combustion is adjusted by the opening of the fuel supply control valve 15.

The condenser 16 has a function of cooling and liquefying the refrigerant vapor sent from the regenerator 12 by an air-cooling fan 17, and converts a part of the refrigerant into the refrigerant in order to adjust the average concentration of the circulating solution. Store in the tank 18.

The absorber 20 stores the absorbing liquid, has a function of absorbing the refrigerant evaporated in the evaporator 10 into the absorbing liquid, and is air-cooled by the same air-cooling fan 17 as the condenser 16. The absorbent whose concentration has been lowered by absorbing the refrigerant is temporarily stored in the dilute solution tank 21.

Reference numeral 22 denotes a dilute solution tank 21 and a regenerator 12.
A heat exchanger 23 for performing heat exchange between a low-temperature absorbent having a low concentration and flowing toward the absorber 20 and a high-temperature absorbent having a high concentration flowing from the regenerator 12 to the absorber 20 absorbs the refrigerant and has a low concentration. A pump 24 for sending the absorbed liquid from the dilute solution tank 21 to the regenerator 12 is provided between the upstream side of the evaporator 10 and the condenser 16.
And a pressure loss member such as a capillary provided between the downstream side and the downstream side.

V1, V2, V3, V4, and V5 are control valves such as solenoid valves. Particularly, V4 has a check function that does not allow a dilute solution to flow from the dilute solution tank 21 to the refrigerant tank 18 side. It is a valve.

The above air conditioner basically controls each container by controlling the temperature of each container except that a pump 23 is used to send the absorbing liquid from the dilute solution tank 21 to the regenerator 12. A pressure difference is created between them, and the refrigerant and the absorbing liquid are sent out and circulated by the pressure difference.

In this type of air conditioner, even when the operating condition is changed by a user's instruction or the operating condition is changed due to a change in the temperature of the outside air or the like, smooth and stable operation is performed according to the current situation. It is required to continue the operation. Stabilizing the circulation of the refrigerant under various conditions in the absorption refrigerator is one means for achieving this demand.

In an air conditioner of a system in which a pump is used only for supplying a dilute solution to a regenerator and the refrigerant itself is circulated by a pressure difference between various parts in the apparatus, a stable circulation of the refrigerant according to the situation is performed. In order to maintain a stable cooling capacity, it is necessary to adjust the pressure of the condenser so as to maintain a predetermined pressure difference with respect to the evaporator having a preset pressure. Since the pressure of the condenser depends on the temperature of the condenser, the pressure of the condenser can be adjusted by adjusting the temperature of the condenser.

Therefore, the present inventors controlled the motor rotation speed of the air cooling fan for cooling the condenser in accordance with the temperature of the condenser, thereby stably sending the liquefied refrigerant from the condenser to the evaporator, and stabilizing the liquefied refrigerant. An air conditioner capable of exerting cooling capacity has been proposed (Japanese Patent Application No. 5-264296).

[0022]

By the way, in the above-mentioned air conditioner, if a conventional PID control method is used for controlling the motor speed of the air cooling fan for cooling the condenser, for example, the external air which is a disturbance is generated. Controllability may be degraded due to fluctuations in the gas input amount according to the temperature or the opening of the fuel supply control valve.

Therefore, it is conceivable to use an optimal regulator by modern control in order to cope with various load fluctuations. In using the optimum regulator, one of the simplest controls to design and perform the optimum regulator is to integrate the deviation between the preset condenser target temperature and the actually measured condenser temperature, and calculate the integrated value. Some control systems reduce deviations. For example, when the integral value is increasing, the rotational speed of the air-cooling fan is increased in proportion thereto, and conversely, when the integral value decreases, the rotational speed is decreased.

Since the rotation speed of the air-cooling fan obtained by the integral value is calculated from the deviation without relation to the actual rotation performance of the air-cooling fan, the air-cooling fan performance calculated by the control device is actually calculated. May exceed the capacity of the air cooling fan. However, even if the calculated value exceeds the actual capacity, it cannot operate beyond the capacity, so the air-cooling fan operates at the limit value of the capacity and operates according to the calculated value when the calculated value moves within the capacity. It will be.

This will be described in detail.
When changing as shown in (a), the output of the integrator follows the OABCD path shown in FIG. 2 (b). If the limit value of the air-cooling fan is L, the actual The rotation speed (operating amount) follows a path called OAECD. At this time, between the AEs, the original function, that is, the function of increasing the number of revolutions in proportion to the increase in the amount of integration of the deviation, is lost, but it is unavoidable because it operates at the limit of the capacity. However, since the integrator output is wound up by AB between ECs, the original function of reducing the number of revolutions in proportion to the decrease in the amount of integration of the deviation until the output is unwinded from BC is the original function. A so-called reset windup phenomenon occurs in which the rotation speed of the air-cooling fan does not decrease although the integral amount of the deviation decreases without recovery.

For this reason, the recovery of the original function is delayed only during the rewind period, and the setting of the deviation is delayed, so that the target temperature is exceeded, that is, so-called overshoot or undershoot occurs, thereby deteriorating the controllability. there were.

The present invention has been made in view of the above points. Even when the calculated air-cooling fan capacity exceeds the limit of the actual capacity, the control disturbance is minimized, and the control is appropriately performed in accordance with the target as much as possible. It is an object of the present invention to provide an air conditioner using an absorption refrigerator capable of performing various controls.

[0028]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides an evaporator for evaporating a refrigerant, an absorbing liquid for absorbing the refrigerant, and a refrigerant vapor evaporated by the evaporator for the absorbing liquid. Absorber to be absorbed, a regenerator that heats the dilute absorbent that has absorbed the refrigerant vapor to generate refrigerant vapor and a concentrated absorbent, and a condenser that condenses the refrigerant vapor generated by the regenerator, The refrigerant is sent from the condenser to the evaporator by the pressure difference between the condenser and the evaporator, the air in the room to be air-conditioned is directly cooled by the evaporator, and the cooled air is cooled through the duct to the room. In an air conditioner using an absorption refrigerator that performs cooling by blowing air, an air cooling fan that cools the condenser, an outside air temperature detecting unit that detects an outside air temperature, and a gas that is burned by a burner that heats the regenerator The amount as a gas input Gas input detection means for detecting the temperature of the condenser, condenser temperature detection means for detecting the temperature of the condenser, capacity storage means for storing the limit capacity of the air cooling fan, and temperature storage for storing an appropriate target temperature of the condenser. Means for calculating the integral of the deviation between the target temperature and the detected condenser temperature in order to eliminate the deviation between the target temperature and the detected condenser temperature, the condenser temperature (T1) and the outside air temperature (T2). ), Calculating means for calculating an appropriate air-cooling fan capacity from the gas input using an optimal regulator theory, and calculating the air-cooling fan when the capacity of the air-cooling fan calculated by the calculating means exceeds the limit of the air-cooling fan capacity. When the condenser temperature is changing in a direction in which the capacity is further away from the range of the capacity of the air cooling fan, the integral calculation is stopped, and the calculated air cooling fan is stopped. Control means for performing the integral calculation when the condenser temperature changes in a direction in which the cooling capacity falls within the range of the ability of the air-cooling fan to actually output, and the air-cooling fan with the rotation speed calculated by the calculating means. An air conditioner was constituted by the driving means for driving the air-cooling fan.

[0029]

[Function] When the calculated air-cooling fan capacity exceeds the limit of the actual air-cooling fan capacity and the air-cooling fan is operating at the limit capacity, the calculated air-cooling fan capacity is the capacity that the air-cooling fan can actually output. When the condenser temperature changes in a direction further away from the range, the integration calculation is stopped, and the condenser temperature changes in a direction in which the calculated air-cooling fan capacity falls within the range of the capacity that the air-cooling fan can actually output. In some cases, the integral calculation is performed and the air-cooling fan capacity is controlled using the optimal regulator theory, so that the reset windup phenomenon when the air-cooling fan capacity reaches saturation is minimized, and the overshoot and undershoot due to operation delays Shooting can be reduced and the adverse effects of control loop instability can be minimized.

[0030]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows an essential part of an embodiment of an air conditioner using a single-effect absorption refrigerator embodying the present invention. The installation state of the air conditioner according to the present invention is as shown in FIG.

The basic configuration of the air conditioner according to the present invention is the same as the configuration shown in FIG. 5, so that the description thereof will be omitted, and the electric circuit necessary for controlling the device will be mainly described.

T1 is a temperature sensor for detecting the indoor temperature provided on the upstream side of the evaporator 10, T2 is a temperature sensor for detecting the blast temperature, T3 is a level sensor for detecting the liquid level of the regenerator, and T4 is a condenser. Temperature sensor for detecting the outlet temperature of the vessel, T
Reference numeral 5 denotes a temperature sensor for detecting the outside air temperature.

The air conditioner includes a controller 30 including a CPU, a memory, and a drive circuit, and a remote controller 6 (FIG. 6).
) Is received by the receiving unit 2a of the indoor unit 2,
A communication controller 31 for receiving a signal from the receiving unit 2a is provided, and the controller 30 includes temperature sensors T1, T
2, signals from T4, T5 and level sensor T3;
Receiving the signal from the communication controller 31,
The operation of the air-cooling fan 17, the pump 23, and the fuel supply control valve 15 is controlled.

The controller 30 further includes an air cooling fan 1
7, a temperature storage means for storing an appropriate target temperature T0 of the condenser 16 during actual operation according to the function of the air conditioner, and a target temperature T0.
In order to eliminate the deviation between the detected condenser temperature T1 and the target temperature T0, the operation unit performs an integral operation of the deviation between the detected condenser temperature T1 and the condenser temperature T1 and the outside air temperature T1.
2. A calculating means for calculating an appropriate air-cooling fan capacity from the gas input by using the optimal regulator theory, and the capacity of the air-cooling fan 17 calculated by the calculating means is determined by the air-cooling fan 1
7, when the condenser temperature T1 changes in a direction in which the calculated air-cooling fan capacity is further away from the range of the capacity that the air-cooling fan 17 can actually output, the integration calculation is stopped. On the other hand, there is provided control means for performing the integral calculation when the condenser temperature T1 changes so that the calculated capacity of the air-cooling fan 17 falls within the range of the capacity that the air-cooling fan 17 can actually output.

Next, the operation of the cooling cycle will be described with reference to FIG.

Before the start of operation, the valves V1, V3, V5 are closed and the valves V2, V4 are open. All of the absorbing liquid is in the dilute solution tank 21, and the regenerator 12 is empty.

When the start button of the remote controller 6 is turned on, the valves V1, V3, V5 are opened and the valves V2, V
4 is closed (F-1), the motor M ₂ is driven pump 2
3, the absorbing solution is sent from the dilute solution tank 21 to the regenerator 12 (F-2). At this time, C in the controller 30
The PU checks the signal from the level sensor T3 to determine whether or not the liquid level of the regenerator 12 has reached a specified level (F
-3). When the liquid level reaches a specified level, the fuel supply control valve 15 is opened to supply fuel gas from the fuel supply pipe 14 and ignite the burner 13 (F-4).

The refrigerant vapor is generated in the regenerator 12 and the condenser 16
And the temperature of the condenser 16 gradually rises due to the temperature of the refrigerant vapor. CPU in the controller 30 determines whether or not the temperature of the condenser 16 by a signal from the temperature sensor T4 has reached a predetermined value (F-5), the cooling fan 17 by the motor M ₁ is when it reaches a predetermined value (F-
6).

In the condenser 16, the vapor refrigerant sent from the regenerator 12 is liquefied, and the liquefied refrigerant flows into the refrigerant tank 18 via the valve V5. At this time, the CPU in the controller 30 determines whether or not the amount of the refrigerant in the refrigerant tank 18 has reached a predetermined amount (F-7). When the amount of the refrigerant has reached the predetermined amount, the valve V5 is closed (F-8). The fan 11 is rotated (F-9).

At this time, the refrigerant from the condenser 16 flows into the evaporator 10 via the capillary 24, and the refrigerant evaporates in the evaporator 10 and is sent from the room through the intake duct 4 by the blower fan 11 by the latent heat due to the latent heat. Cool the air. The cooled air is sent to the indoor unit 2 through the air duct 3 and is blown out as cold air into the room 5 to cool the room 5 (F-10).

In this cooling operation, the refrigerant evaporated to vapor in the evaporator 10 flows into the absorber 20, where it is absorbed by the absorbing liquid. The absorption liquid whose concentration has been reduced by absorbing the refrigerant once enters the dilute solution tank 21 and is then pumped.
Is exchanged with the high-concentration high-temperature absorbent discharged from the regenerator 12 in the heat exchanger 22 through the valve V3. This state is the steady mode of operation.

When the start button of the remote controller 6 is turned off (F-11), a stop process is performed (F-12) and the process ends. In the stop processing, first, the burner 13 is extinguished, the valves V2 and V4 are opened, and the valve V1 is closed. Next, after a while, the pump 23 is stopped, the valve V3 is closed, and the blower fan 11 and the air cooling fan 17 are stopped. By doing so, the refrigerant in the refrigerant tank 18 and the regenerator 1
All of the absorption liquid in 2 flows into the dilute solution tank 21. This is because while the device is stopped, the refrigerant tank 1
8 and the regenerator 12 to prevent corrosion and dilute the concentrated solution to prevent crystallization.

Next, an air conditioner using an absorption refrigerator is
Control according to the present invention for continuing smooth and stable operation according to the situation at that time will be described.

In this embodiment, first, when creating a servo system model for controlling the outlet temperature of the condenser 16,
The outside air temperature detected by the temperature sensor T5, the amount of supply gas according to the opening of the fuel supply control valve 15 (hereinafter referred to as "gas input"), and the motor M for rotating the air cooling fan 17
The rotation speed of ₁ is input, and the outlet temperature of the condenser 16 detected by the temperature sensor T4 is modeled as an output. An example of this model is shown in Equation 1.

[0046]

[Number 1] _{y (t) + a 1 ·} y (t-1) + a 2 · y (t-2) = b 0 · u b (t) + b 1 · u b (t-1) + b _{2 · u b (t-2} ) + c 0 · u c (t) + c 1 · u c (t-1) + c 2 · u c (t-2) + d 0 · u d (t) + in _{d 1 · u d (t-} 1) + d 2 · u d (t-2) number _{1, u b (t),} u c (t), u d (t)
Are inputs corresponding to the outside air temperature, the gas input, and the number of rotations of the air-cooling fan, respectively, y (t) is an output corresponding to the condenser outlet temperature, and t is the time when sampling is performed in time series. This is the sample number. The model order is second order.

These input / output values can be obtained by operating the air conditioner such that each input value is close to the value in the actual operating environment, and measuring each value at predetermined time intervals. For example, if the environment of the place where the air conditioner is installed has an outside air temperature of about 25 ° C., the environment is created experimentally, and each input / output value is measured at predetermined time intervals. Here, each input / output value is actually measured assuming that the outside air temperature is around 25 ° C.

Equation 1 is an ARX model in which the delay of the system is 0. Here, the ARX model is a discrete-value model that assumes that the input and output of the system to be controlled have a time-series relationship as shown in Equation 1.

Next, by converting the time series model of Equation 1 into a matrix expression (state space type), the state equation of Equation 2 and the output equation of Equation 3 are established.

[0050]

X (t + 1) = AｔX (t) + BU ・ (t)

[0051]

Y (t) = C ・ X (t) + DU ・ (t) In Equations 2 and 3, U (t) is an input, Y (t) is an output, and X (t) is a state variable. is there.

The input U (t) in Equations 2 and 3
(In this embodiment, the outside air temperature, the gas input, and the number of rotations of the air-cooling fan are combined into one matrix.) The output Y (t) (in this embodiment, the condenser outlet temperature) and X (1) are Once obtained, the coefficients A, B, C, and D of the above state equation and output equation can be calculated. Calculating the coefficients A, B, C, and D and formulating the relationship between the input and the output in this manner is called system identification.

FIG. 4 is a state variable diagram of the servo system of the air conditioner according to the present invention, which is modeled as Equations 1 to 3.

In FIG. 4, reference numeral 35 denotes a servo system to be controlled, and 36 denotes a CP in the controller 30 shown in FIG.
This is an additional integrator realized by U. U (k) is the number of rotations of the air-cooling fan which is an input to the control target, x (k) is a state variable, and y (k) is the condenser 1 measured by the temperature sensor T4.
6, r (k) is a target value of the outlet temperature of the condenser 16, e (k) is a difference obtained by subtracting an actually measured value from the target value of the outlet temperature of the condenser 16, and z (k) is This is an integrated value of a difference obtained by subtracting an actually measured value from a target value of the temperature at the outlet of the condenser 16.

In order to realize the control of the state variable diagram shown in FIG. 4, it is necessary to obtain the feedback gains F ₁ and F ₂ . Therefore, next, a method of obtaining the feedback gains F ₁ and F ₂ will be described.

The feedback gains F ₁ and F ₂ are
It is obtained by evaluating the state equation of Equation 2 and finding an optimal solution. Equation 4 is a quadratic form evaluation function serving as an index of this evaluation.

[0057]

(Equation 4) In Equation 4, X ^T and U ^T are transposes of matrices X and U, respectively, and Q and R are weight matrices.

Optimum control is to determine the control input U so as to minimize the value J of the evaluation function shown in equation (4).
An increase in the weight matrix Q results in an increase in the responsiveness of X, while an increase in the weight matrix R results in a decrease in the control input U. In designing an optimal regulator, a designer determines weight matrices Q and R in advance based on the responsiveness required for the system, input restrictions, and the like.

As described above, the value J of the evaluation function shown in Expression 4 is obtained.
Is obtained, the feedback gains F ₁ and F ₂ can be obtained.

In this embodiment, in the output equation of Equation 3, C = [1,0] and D = 0, X (1) is set to an appropriate value, and the feedback gains F ₁ and F ₂ are obtained. . The feedback gains F ₁ and F ₂ are obtained in advance as described above, and stored in the memory of the controller 30 in advance. The memory in which the feedback gain is stored in advance is preferably a non-volatile memory (for example, a ROM) that does not lose its stored contents even if power is not supplied to the air conditioner.

When controlling the temperature at the outlet of the condenser 16, the rotation speed of the air-cooling fan is obtained by the equation 5, and the air-cooling fan 17 is rotated at this rotation speed.

[0062]

(Equation 5) In the equation (5), (r (t) -y (t)) is the condenser 1
6 is a difference obtained by subtracting the actually measured value from the target value of the outlet temperature, that is, e (t).

As described above, by controlling the rotation speed of the air-cooling fan 17 of the air conditioner and adjusting the temperature of the outlet of the condenser 16, control by the optimum regulator can be realized. The range in which this good controllability is obtained is called the allowable operating range of the optimal regulator.

As described above, the feedback gains F ₁ and F ₂ are obtained by actually measuring input / output values under actual conditions in an environment where the outside air temperature is about 25 ° C. When the temperature is around 25 ° C., good controllability can be obtained. However, in an environment where the outside air temperature deviates greatly from this, or when the set temperature is largely changed, the calculated air cooling fan capacity becomes smaller than the actual air cooling fan capacity. The capacity of the fan 17 may be exceeded.

Next, control in such a case will be described.

For example, when the actual outside air temperature greatly exceeds the assumed outside air temperature, it is desired to increase the cooling capacity, and a control output exceeding the capacity of the air cooling fan 17 may be sent to the air cooling fan 17. However, the air-cooling fan 17 cannot operate at the capacity exceeding the capacity, and the air-cooling fan 17 operates at its own limit capacity irrespective of the output from the arithmetic means, and at the same time, the integral calculation of the deviation by the arithmetic means is stopped. When a certain time has elapsed and the temperature of the condenser 16 has decreased, the temperature change is a temperature change in the direction of decreasing the air cooling fan capacity, and the calculated value of the air cooling fan capacity exceeds the actual capacity of the air cooling fan 17. The control means instructs the start of the integral calculation of the deviation, and the integral operation is started.

Therefore, the capacity of the air-cooling fan 17 changes along the OAEF path shown in FIG.
There is no delay with respect to the deviation, and the overshoot can be prevented from expanding. For this reason, even if the calculated value is output beyond the limit of the capacity of the air-cooling fan 17, control disturbance is suppressed to a minimum, and an air conditioner with a wide applicable range can be provided.

In the above example, the case where the control amount exceeds the upper limit of the capacity of the air-cooling fan 17 has been described. However, the present invention is not limited to this, and the lower operation limit of the air-cooling fan 17 (not necessarily stop). Even if the control signal is transmitted with a value exceeding the above, it is possible to detect the temperature change that increases the capacity of the air-cooling fan 17 and apply the same in the same manner to cope with the occurrence of undershoot.

In this embodiment, the optimal regulator is designed using the ARX model, but it may be calculated by using a least square method or a prediction error method using another model.

Further, in the present embodiment, an aqueous solution of lithium bromide was used as the absorbing solution and water was used as the refrigerant. However, the present invention is not limited to this. For example, the present invention can be applied to a case where ammonia is used as the refrigerant. .

[0071]

According to the air conditioner of the present invention, even when the air cooling fan capacity calculated by calculation exceeds the actual air cooling fan capacity and the air cooling fan capacity reaches saturation,
When the calculated air-cooling fan capacity is farther away from the range of the capacity of the air-cooling fan, the integration operation is stopped when the condenser temperature is changed, and the calculated air-cooling fan capacity is actually increased. Integral calculation is performed when the condenser temperature changes within the range of the capacity to be obtained, so that the reset windup phenomenon is minimized, the control delay is eliminated, and the original control contents can be achieved. Control that follows as long as possible can be performed. Therefore, it is possible to provide an air conditioner using an absorption refrigerator that can reduce overshoot and undershoot, suppress significant modulation of control, and can be used well under a wide range of conditions.

[Brief description of the drawings]

FIG. 1 is a block diagram of a main part of an embodiment of an air conditioner according to the present invention.

FIG. 2A is a graph showing a deviation of an air conditioner,
(B) is a graph of the calculated air-cooling fan capacity.

FIG. 3 shows a flowchart of a steady mode of operation of the air conditioner according to the present invention.

FIG. 4 is a state variable diagram of a servo system of the air conditioner according to the present invention, which is modeled as Equations 1 to 3.

FIG. 5 is a block diagram of a main part of a modification of an air conditioner using a single-effect absorption refrigerator proposed in the prior application.

FIG. 6 shows an installation state of the air conditioner shown in FIG.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 outdoor unit 2 indoor unit 3 air duct 4 air intake duct 5 room 6 remote controller 10 evaporator 11 air fan 12 regenerator 13 burner 14 fuel supply pipe 15 fuel supply control valve 16 condenser 17 air cooling fan 18 refrigerant tank 20 absorber 21 dilute solution tank 30 controller 31 communication controller T1, T2, T4, T5 temperature sensor T3 level sensor V1, V2, V3, V4, V5 valve M _1, M ₂ motor

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-1-260268 (JP, A) JP-A-2-259373 (JP, A) JP-A-6-101928 (JP, A) JP-A-6-191928 2927 (JP, A) JP-A-8-29005 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F25B 15/00 306

Claims (2)

(57) [Claims] 1. An evaporator for evaporating a refrigerant, an absorber for storing an absorbing liquid for absorbing the refrigerant and absorbing the refrigerant vapor evaporated by the evaporator to the absorbing liquid, and heating the rare absorbing liquid having absorbed the refrigerant vapor. And a condenser for condensing the refrigerant vapor generated in the regenerator, and a condenser for condensing the refrigerant vapor generated in the regenerator, wherein a pressure difference between the condenser and the evaporator causes the condenser to evaporate from the condenser. An air conditioner using an absorption refrigerator that sends a refrigerant to the evaporator, directly cools room air to be air-conditioned by the evaporator, and blows the cooled air into the room through a duct to perform cooling. In the above, an air cooling fan for cooling the condenser, an outside air temperature detecting means for detecting an outside air temperature, a gas input detecting means for detecting an amount of gas burned by a burner for heating the regenerator as a gas input, and the condensation Condenser temperature detection means for detecting the temperature of the condenser; capacity storage means for storing the limit capacity of the air cooling fan; temperature storage means for storing an appropriate target temperature of the condenser; and a target temperature and the detected condenser temperature. To eliminate the deviation between the target temperature and the detected condenser temperature.
2) a calculating means for calculating an appropriate air-cooling fan capacity from the gas input by using an optimal regulator theory; and calculating when the capacity of the air-cooling fan calculated by the calculating means exceeds a limit of the capacity of the air-cooling fan. When the condenser temperature is changed in a direction in which the air-cooling fan capacity is further away from the range of the capacity of the air-cooling fan, the integration operation is stopped, and the calculated air-cooling fan capacity can actually output the air-cooling fan. Control means for performing the integral calculation when the condenser temperature changes in a direction falling within the range of the capacity; and air-cooling fan driving means for driving the air-cooling fan at the rotation speed calculated by the calculating means. An air conditioner using an absorption refrigerator. 2. The air conditioner using an absorption refrigerator according to claim 1, wherein the condenser temperature detecting means detects a temperature at an outlet of the condenser.