JP3399664B2 - Air conditioner using absorption refrigerator - Google Patents

Description

Description: 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. 2. Description of the Related Art Air conditioners using absorption chillers are currently mainly used in industrial and commercial facilities such as buildings and large stores. 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 air-conditioned and the refrigerator is cooled by the latent heat of evaporation. 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. The method of cooling with is taken. [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. 4 shows an essential part of a modification of the air conditioner using the single-effect absorption refrigerator proposed in the above-mentioned application, and FIG. 5 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. 4, 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 cool air to be blown. The interior of the outdoor unit 1 has a configuration as shown in FIG. 4, in which an aqueous solution of lithium bromide is used as an absorbing solution, and water is used as a refrigerant. The evaporator 10 evaporates the refrigerant under reduced pressure,
It has a function of cooling the air passing therethrough by the latent heat of evaporation, and is connected to the air duct 3 and the intake duct 4. A blower fan 11 is provided in the intake duct 4. The regenerator 12 has a function of generating refrigerant vapor by heating the rare absorbing liquid having a reduced concentration by absorbing the refrigerant by the burner 13 and concentrating the concentration of the absorbing liquid. Fuel gas is supplied to the burner 13 from a fuel supply pipe 14, and the degree of combustion is determined by a fuel supply control valve 15.
Is adjusted by The condenser 16 has a function of cooling and liquefying the refrigerant vapor sent from the regenerator 12 by the air-cooling fan 17, and a part of the refrigerant is stored in the refrigerant tank 18 to adjust the concentration of the circulating solution. To store. 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 diluted absorbing liquid whose concentration has been lowered by absorbing the refrigerant is temporarily stored in the diluted solution tank 21. Reference numeral 22 denotes a dilute solution tank 21 and a regenerator 12.
A heat exchanger 23 for exchanging heat between a low-temperature diluted absorbent having a low concentration toward the regenerator 12 and a high-temperature concentrated absorbent having a high concentration flowing from the regenerator 12 to the absorber 20. The lowered diluted absorbing solution is supplied from the diluted solution tank 21 to the regenerator 12.
A pump 24 is a pressure loss member such as a capillary provided between the upstream side of the evaporator 10 and the downstream side of the condenser 16. V1, V2, V3, V4, and V5 are all valves such as solenoid valves.
This is a valve having a check function that does not allow the refrigerant to flow from the side to the refrigerant tank 18 side. 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 is sent out and circulated by the pressure difference. By the way, the condenser 16 of the above-mentioned air conditioner is provided with a number of pipes having cooling fins formed at intervals of 2 mm on the outside. To cool and vaporize the refrigerant vapor by sending air from the air-cooling fan 17. However, while the condenser 16 has been used for a long period of time, dust and dirt accumulate between the cooling fins to cause clogging, dirt adheres to the cooling fins, and the cooling fins themselves deteriorate. There is a risk. If this state is left, the condenser 1
Since the cooling capacity of the condenser 6 decreases, the condensed refrigerant temperature of the condenser 16 continues to rise even if the air cooling fan 17 is rotated at the maximum capacity, and it is impossible to lower the condensed refrigerant to an appropriate temperature. Generally, since there is a correlation between the pressure and the temperature, in order to send the refrigerant from the condenser 16 to the evaporator 10 by the pressure difference, the outlet temperature of the condenser 16 must be higher than the inlet temperature of the evaporator 10. In other words, it is necessary to keep the outlet temperature of the condenser 16 constant for the evaporator 10 having a preset pressure, but the cooling capacity of the condenser 16 decreases, If the outlet temperature of the condenser 16 becomes too high, the condenser 16 and the evaporator 10
The pressure difference becomes too large, causing a rapid pressure drop at the inlet of the evaporator 10, causing a phenomenon (flashing) in which the refrigerant is vaporized and blown out.
There is a problem that the cooling efficiency of the air at 0 is greatly reduced. The present invention has been made in view of the above points, and detects when the cooling fins of a condenser have deteriorated over time or are blocked due to dirt and the cooling capacity of the condenser has been reduced. The amount of fuel gas supplied to the burner that heats the regenerator is reduced to an allowable value to reduce the amount of refrigerant vapor generated, thereby lowering the outlet temperature of the condenser, and allowing the condenser to evaporate. It is an object of the present invention to provide an air conditioner that can prevent a problem of sending out a condensed refrigerant. In order to achieve the above object, the present invention provides an evaporator for evaporating a refrigerant and a refrigerant vapor storing an absorbing liquid for absorbing the refrigerant and evaporating in the evaporator. An absorber for absorbing the absorbing liquid, a regenerator for heating the diluted absorbing liquid that has absorbed the refrigerant vapor to generate the refrigerant vapor and the concentrated absorbing liquid, and a cooling fin for condensing the refrigerant vapor generated in the regenerator. Having a condenser, causing the refrigerant to be sent from the condenser to the evaporator by a pressure difference between the condenser and the evaporator, and directly cooling the indoor air to be air-conditioned by evaporating the refrigerant in the evaporator. In an air conditioner using an absorption refrigerator that blows the cooled air into a room through a duct to perform cooling, an air-cooling fan that cools the condenser and a burner that heats the regenerator are used for combustion. Gas supply Fuel supply control means for controlling the temperature based on the difference between the room temperature and the set temperature, and the condenser outlet at a rotational speed determined stepwise or steplessly based on the outside air temperature and the supplied gas amount. Air-cooling fan rotation control means for controlling the rotation of the air-cooling fan so as to maintain the temperature at a predetermined appropriate condenser outlet temperature; and a gas supply amount for keeping the gas supply amount within a predetermined range stepwise or steplessly. Storage means for storing the allowable range of the condenser outlet temperature when it is determined that the condenser outlet temperature continues to rise even if the air-cooling fan rotates at the maximum capacity for a predetermined time or more, and the condenser outlet temperature and the proper condenser outlet temperature And control means for reducing the gas supply amount to an allowable limit based on the allowable range stored in the storage means when the difference from the predetermined value does not fall below a predetermined value. According to the present invention, the air conditioner is started, the number of rotations of the air-cooling fan for keeping the condenser outlet temperature constant is detected, and the air-cooling fan is condensed even though it is rotating at the maximum capacity. The fuel gas supply amount to the burner for heating the regenerator when it is determined that the outlet temperature of the regenerator has continued to rise, or when the difference between the outlet temperature of the condenser and the appropriate outlet temperature of the condenser does not fall below a predetermined value. Is reduced to an acceptable value to reduce the amount of refrigerant vapor generated, thereby reducing the condenser outlet temperature. Therefore, even if the cooling capacity of the condenser is reduced, it is possible to prevent the refrigerant from being sent from the condenser to the evaporator. 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 configuration of the air conditioner according to the present invention is the same as that shown in FIG. 4, and therefore the description thereof is omitted. However, water is used as the refrigerant and lithium bromide is used as the absorbing liquid. Referring to FIG. 1, the electric circuit required for controlling the air conditioner according to the present invention and the operation of the device will be described. T1 is a sensor for detecting the indoor temperature provided on the upstream side of the evaporator 10, T2 is a sensor for detecting the air temperature provided on the downstream side of the evaporator 10, and T3 is a liquid level detection of the regenerator. T4 is a sensor for detecting the condenser temperature, T5 is a sensor for detecting the outside air temperature, and T6 is a sensor for detecting the condenser outlet temperature. The air conditioner includes a controller 30 including a CPU, a memory, and a drive circuit, and a remote controller 6.
A communication controller 31 is provided for receiving the setting signal from the receiving unit 2a of the indoor unit 2 and receiving a signal from the receiving unit 2a (see FIG. 5).
Upon receiving signals from T2, T4, T5, T6 and the level sensor T3 and a signal from the communication controller 31, the blower fan 11, the air cooling fan 17, the pump 23, the fuel supply pipe 14
Fuel supply control valve 15, valves V1, V2, V3, V4, V
5 is controlled. Next, the operation of the cooling cycle will be described with reference to FIG. Before starting the 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 and V5 are opened and the valves V2 and V4 are opened.
Closes (F-1), the motor M ₂ is driven pump 23
As a result, the absorbent is sent from the dilute solution tank 21 to the regenerator 12 (F-2). At this time, the CPU of the controller 30
Determines from the signal from the level sensor T3 whether or not the liquid level of the regenerator 12 has reached a specified level (F-
3). When the liquid level has reached the 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 increases. The CPU of the controller 30 determines whether or not the temperature of the condenser 16 has reached a predetermined value based on a signal from the temperature sensor T4 (F−
5), when it reaches a predetermined value to rotate the cooling fan 17 by the motor M ₁ (F-6). In the condenser 16, the refrigerant vapor 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 controller 3
The CPU within 0 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) and the blower fan 11 is turned off. Rotate (F-9). At this time, the refrigerant from the condenser 16 flows into the evaporator 10 via the capillary 24, where the refrigerant evaporates and takes away latent heat of evaporation. Cools the air coming from. 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 and vaporized in the evaporator 10 flows into the absorber 20, where it is absorbed by the absorbing liquid. The diluted absorption liquid whose concentration has been lowered by absorbing the refrigerant once enters the diluted solution tank 21 and is then pumped.
3, heat exchange with the high-concentration, high-concentration absorbent sent out of the regenerator 12 in the heat exchanger 22 through the valve V3,
It is sent to the regenerator 12. This state is the steady mode of operation. Here, the temperature and pressure of the container, the absorbing liquid, and the refrigerant in each part of the system during the cooling cycle operation are as follows. Temperature (° C.) Pressure (Torr) Evaporator 10: 10-20 10-20 Regenerator 12: 60-90 90-110 Condenser 16: 50-80 90-110 Absorber 20: 45-50 11 Refrigerant tank 18: 30 to 50 40 to 50 Dilute solution tank 21: 40 to 60 11 Heat exchanger 22: 30 to 90-Intake duct 4: 26 (room temperature)-Blast duct 3: 10 to 15-Dilute solution: 35 -40 concentration: 61% concentrated solution: 90 concentration: 64.8% When the start button of the remote controller 6 is turned off (F-
11) After the stop processing is performed (F-12), the processing ends. As the stop processing, first, the burner 13 is extinguished, and the valve V2,
Open V4 and close valve V1. 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 absorbing liquid in the regenerator 12 all flow into the dilute solution tank 21. This is because the refrigerant tank 18 and the regenerator 1
2 to prevent corrosion and dilute the concentrated solution to prevent crystallization. By the way, the above air conditioner basically controls each container by controlling the temperature of each container except that the pump 23 is used to send the absorbing liquid from the absorber 20 to the regenerator 12. A pressure difference is created between them, and the refrigerant is sent and circulated by the pressure difference. Therefore, since the refrigerant is also sent from the condenser 16 to the evaporator 10 by the pressure difference, the outlet temperature of the condenser 16 is always constant with respect to the evaporator 10 having a preset pressure (in this embodiment, the outlet temperature is constant). 45 ° C.). Here, the temperature of the condenser 16 depends on the change in the amount of refrigerant vapor generated based on the change in the amount of heating in the regenerator 12 and the change in the outside air temperature. For example, if the amount of generated refrigerant vapor increases or the outside air temperature increases, the condenser 16
Therefore, in order to keep the outlet temperature of the condenser 16 constant, the rotation speed of the air-cooling fan 17 must be increased or decreased according to the temperature change. Therefore, the outlet temperature of the condenser 16 is always detected by the sensor T6, and the detected temperature is sent to the controller 30. The controller 30 corrects the outlet temperature of the condenser 16 (the outlet temperature of the condenser 16 stored in the memory). In this embodiment, 4
The rotation speed of the motor M1 of the air-cooling fan 17 is controlled so as to be maintained at 5 ° C.). However, as described above, the condenser 16
When the rotation speed of the air-cooling fan 17 is controlled based only on the outlet temperature of the outdoor unit, in a situation where the installation environment of the outdoor unit is unexpectedly poor or the outdoor unit has an abnormality and the outlet temperature of the condenser 16 is difficult to decrease, It is conceivable that the air-cooling fan 17 may abnormally rotate at a high speed and greatly affect the life and performance of the device. Therefore, it is absolutely necessary to stop the rotation at a certain speed. Therefore, the air-cooling fan 17 for a certain period of time
May be stored in the memory 32 so that the rotation of the air-cooling fan 17 does not exceed this allowable range. Further, if the allowable range of the number of revolutions of the air-cooling fan 17 is set in a stepwise manner as described below, fine-grained control is possible. That is, the provisional value of the rotation speed of the air-cooling fan 17 for keeping the outlet temperature of the condenser 16 at 45 ° C. depends on the outside air temperature, the heating amount in the regenerator 12, that is, the amount of the fuel gas supplied from the fuel supply pipe 14. The allowable range of the rotation speed of the air-cooling fan 17 for a combination of a certain outside air temperature and the amount of the supplied fuel gas is stored in the memory 32 in advance.
From the combination of the outside air temperature detected by the sensor T5 and the amount of the supplied fuel gas, the rotation of the air cooling fan 17 may be controlled so as not to exceed the allowable range stored in the memory 32. On the other hand, the amount of refrigerant vapor generated in the regenerator 12 which affects the temperature of the condenser 16 is based on the amount of fuel gas supplied from the fuel supply pipe 14 for heating the regenerator 12. Is controlled by the controller 30 opening and closing the fuel supply control valve 15. The control of the supply amount of the fuel gas by the controller 30 is performed based on the air conditioning load calculated from the difference between the room temperature detected by the sensor T1 and the set temperature set by the remote controller 6. That is, in the controller 30, the sensor T
The air-conditioning load is calculated from the difference between the room temperature detected in step 1 and the set temperature set by the remote control device 6, and then the amount of air to be blown from the blower fan 11 that matches the obtained air-conditioning load is determined. The amount of evaporation required for the evaporator 10 is calculated from the amount of air blown. The amount of heat of the burner 13 required to generate the refrigerant having the evaporation amount obtained by this calculation in the regenerator 12 is calculated, and the fuel gas supply amount is adjusted by the fuel supply control valve 15 so that the amount of heat is obtained. Open and close to adjust. If the cooling capacity of the condenser 16 is reduced and the outlet temperature of the condenser 16 cannot be reduced to an appropriate temperature even if the air cooling fan 17 is rotated at the maximum capacity, Since the condensed refrigerant temperature of 16 depends on the outside air temperature and the amount of refrigerant vapor generated in the regenerator 12, if the amount of refrigerant vapor generated in the regenerator 12 is reduced (that is, the fuel supply control valve 15 is adjusted) If the amount of supply of the fuel gas is reduced, the outlet temperature of the condenser 16 can be reduced. However, in order to lower the outlet temperature of the condenser 16, the supply amount of the fuel gas cannot be reduced without limit. That is, as described above, the supply amount of the fuel gas is basically calculated to an optimum value based on the air conditioning load. If the supply amount of the fuel gas is reduced from that value, the evaporator 10 The cooling efficiency of the air in the air necessarily decreases. For this reason, even if the supply of fuel gas is reduced by reducing the cooling efficiency in the evaporator 10 to some extent in order to lower the outlet temperature of the condenser 16 and the supply of the fuel gas is reduced, it is necessary to keep the fuel gas within a certain limit. Cycle operation is not possible. Therefore, in this embodiment, when the outlet temperature of the condenser 16 continues to rise or cannot be lowered to the proper temperature even when the air-cooling fan 17 is rotated at the maximum capacity, the memory is stored in advance. An allowable range of the supply amount of the fuel gas is set at 32, and the supply of the fuel gas is reduced within the allowable range. In this case, if the permissible range is determined stepwise according to, for example, the air-conditioning load, more fine-grained control is possible. Next, the operation when the cooling capacity of the condenser 16 is reduced will be described with reference to FIG. Here, it is assumed that data of the allowable range of the rotation speed of the air-cooling fan 17 and data of the allowable range of the supply amount of the fuel gas are already stored in the memory 32. When the air conditioner is started and the operation of the air cooling fan 17 is started (P-1), the outlet temperature of the condenser 16 is detected by the sensor T6, and the air cooling fan is controlled by the controller 30 so as to maintain the outlet temperature of the condenser 16 at 45C. 17 is controlled (P-2). Further, the actual rotation speed of the air cooling fan 17 for keeping the outlet temperature of the condenser 16 at 45 ° C. is detected and stored in the memory 32 (P-3). Next, whether or not the rotation speed of the air-cooling fan 17 detected in step (P-3) has reached the upper limit of the rotation speed stored in the memory 32, that is, whether the air-cooling fan 17
It is determined whether or not is rotating at the maximum capacity (P-
4). If the rotation of the air cooling fan 17 has not reached the maximum capacity, the process returns to step (P-3). On the other hand, when it is determined that the rotation of the air-cooling fan 17 has reached the maximum capacity, measurement is performed for a certain time from that point in time, and it is determined whether the rotation of the maximum capacity continues during that time (P-5). If the rotation speed of the air-cooling fan 17 decreases before the fixed time elapses, the data of the rotation speed stored in the memory 32 is cleared, and the process returns to step (P-3). On the other hand, if it is determined that the rotation of the air-cooling fan 17 at the maximum capacity has continued for a certain period of time, the sensor T6
Is stored in the memory 32 in chronological order (P-6). When the air-cooling capacity of the condenser 16 decreases due to clogging of the cooling fins of the condenser 16 as the use period of the air conditioner becomes longer, the air-cooling fan 17 rotates at the maximum capacity for a certain period of time or more. Also, the outlet temperature of the condenser 16 is hardly reduced. If the outlet temperature of the condenser 16 stored in time series in step (P-6) continues to rise, the opening and closing of the fuel supply control valve 15 is immediately adjusted to reduce the fuel gas supply amount to an allowable range. (P-10). On the other hand, in step (P-7), the condenser 16
If it is determined that the outlet temperature has not risen, the difference from the proper condenser outlet temperature (45 ° C. in this embodiment) stored in the memory 32 is stored in chronological order (P−
8). If the difference does not become equal to or less than the predetermined value after the measurement for a certain period of time (P-9), the opening and closing of the fuel supply control valve 15 is adjusted to reduce the supply amount of the fuel gas to an allowable range (P-10). . If the difference is equal to or less than the predetermined value, the data stored in time series up to that point is cleared, and the process returns to step (P-3). In the above embodiment, when the air-cooling fan 17 rotates at the maximum capacity, the outlet temperature of the condenser 16 rises (1) or (2) the difference between the outlet temperature of the condenser 16 and the proper outlet temperature is equal to or more than a certain value. Although the supply amount of the fuel gas is reduced by combining the two determination criteria, only one of the determination means may be provided. As described above, the air conditioner according to the present invention has the ability to cool the condenser due to the deterioration of the cooling fins of the condenser over time or the blocking due to dirt. The decrease is detected from the fluctuation of the rotation speed of the air-cooling fan, and the supply amount of the fuel gas to the burner for heating the regenerator is reduced to an allowable value to reduce the amount of the refrigerant vapor generated, thereby reducing the amount of the refrigerant vapor. Can prevent the phenomenon that the refrigerant is vaporized and blown out at the inlet of the evaporator due to insufficient cooling in the condenser (flushing), and the stable cooling operation of the air conditioner can be prevented. It becomes possible.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of an embodiment of an air conditioner according to the present invention. FIG. 2 shows a flowchart of an operation operation in a steady mode of the air conditioner according to the present invention. FIG. 3 is a flowchart showing an operation when a cooling fin of a condenser of an air conditioner according to the present invention is clogged. FIG. 4 is a block diagram of a modification of the air conditioner proposed by the present applicant. FIG. 5 shows an installation state of the air conditioner. [Description of Signs] 1 outdoor unit 2 indoor unit 3 ventilation duct 4 air intake duct 5 room 6 remote controller 10 evaporator 11 ventilation 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, T3, T4, T5, T6 Sensor V1, V2, V3, V4, V5 Valve

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F25B 15/00 306

Claims (1)

(57) [Claim 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, A regenerator for heating the diluted absorbing liquid that has absorbed the vapor to generate a refrigerant vapor and a concentrated absorbing liquid, and a condenser with cooling fins for condensing the refrigerant vapor generated by the regenerator; The refrigerant is sent from the condenser to the evaporator by a pressure difference between the evaporator and the evaporator, the air in the room to be air-conditioned is directly cooled by evaporation of the refrigerant in the evaporator, and the cooled air is passed through a duct. In an air conditioner using an absorption refrigerator that blows air into a room to perform cooling, an air cooling fan that cools the condenser, and a gas supply amount for burning by a burner that heats the regenerator are set to a room temperature and a set temperature. Based on the difference between A fuel supply control means for controlling the condenser outlet temperature to a predetermined appropriate condenser outlet temperature within a range of a rotational speed determined stepwise or steplessly based on the outside air temperature and the supplied gas amount. Air-cooling fan rotation control means for controlling the rotation of the air-cooling fan; storage means for storing an allowable range of the gas supply amount in order to keep the gas supply amount in a predetermined range stepwise or steplessly; When the condenser outlet temperature is determined to continue to increase even if it rotates at the maximum capacity for a certain period of time or when the difference between the condenser outlet temperature and the proper condenser outlet temperature does not become a predetermined value or less, the storage is performed. Control means for reducing the gas supply amount to an allowable limit based on the allowable range stored in the means.