JPH07103602A - Air conditioning system using absorption refrigerator - Google Patents

Abstract

(57) [Abstract] [Purpose] To prevent the crystallization of the absorbing liquid and to provide an efficient air conditioner by changing the average concentration of the absorbing liquid that circulates in the cooling cycle according to the fluctuation of the outside air temperature. . [Structure] The refrigerant tank 18 is opened by opening a valve V4 when the outside air temperature detected by the sensor T5 is lowered.
When the outside air temperature rises, the amount of refrigerant in
By opening 5, the amount of refrigerant in the refrigerant tank 18 is increased.

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 refrigerating machine for general houses and small buildings.

[0002]

2. Description of the Related Art At present, an air conditioner using an absorption chiller is mainly used for industrial or commercial facilities such as a building or a large store.

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 for evaporation. The cooling heat medium (usually water) that circulates between the fan coil unit provided in the room to be cooled and the refrigerator is cooled by the latent heat of vaporization at that time. On the other hand, the evaporated refrigerant vapor is operated in a cycle in which a water-cooled absorber absorbs the concentrated solution (absorption liquid) and returns it to the regenerator.

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

However, the conventional air conditioner using the absorption type refrigerating machine adopting such a water cooling system has the following problems.

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

(2) Since it is necessary to connect the fan coil unit and the refrigerator in the room to be cooled by the pipe for circulating the heating / cooling medium, the construction cost and equipment cost are high. The same applies to an ammonia absorption refrigerator that uses ammonia water as the absorbing liquid and the refrigerant.

Therefore, the present inventors carry out a cooling cycle operation in which the condenser and the absorber are cooled by an air cooling method instead of a water cooling method, and the air to be cooled is directly passed through an evaporator instead of using a cooling / heating medium. A patent application has already been filed for the air conditioner (Japanese Patent Application No. 5-22351).

FIG. 7 shows a main part of a modified example of an air conditioner using the single-effect absorption refrigerator proposed in the above application, and FIG. 8 shows an installed state of the air conditioner.

As shown in FIG. 8, the air conditioner includes an outdoor unit 1
The outdoor unit 1 is disposed outside the room 5 of the house to be air-conditioned with the configuration shown in FIG. 7, and the indoor unit 2 has only the outlet for cool air and the inlet for indoor air. It has and is arranged inside the chamber 5. The outdoor unit 1 and the indoor unit 2 are connected by a blower duct 3 for cold air and an intake duct 4 for indoor air. Reference numeral 6 is a remote controller for starting or stopping the operation of the apparatus, setting or canceling the automatic operation, setting the room temperature, adjusting the amount of blown cold air, and the like.

The inside of the outdoor unit 1 is constructed as shown in FIG. 7, in which an aqueous lithium bromide solution is used as the absorbing liquid and water is used as the refrigerant.

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

The regenerator 12 has the functions of absorbing the refrigerant and heating the absorbent having a low concentration by the burner 13 to generate refrigerant vapor and to concentrate the absorbent. Fuel gas is supplied to the burner 13 from a fuel supply pipe 14, and the degree of combustion is adjusted by a fuel supply control valve 15.

The condenser 16 has a function of cooling the refrigerant vapor sent from the regenerator 12 by the air cooling fan 17 and liquefying it, and a part of the refrigerant is stored in the refrigerant tank in order to adjust the average concentration of the circulating solution. Store in 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 cooled by the same air cooling fan 17 as the condenser 16. The absorbing liquid which has absorbed the refrigerant and has a low concentration is temporarily stored in the dilute solution tank 21.

Reference numeral 22 denotes the regenerator 12 from the dilute solution tank 21.
The heat exchanger 23, which performs heat exchange between the low-temperature and high-concentration absorption liquid flowing from the regenerator 12 and the high-concentration high-temperature absorption liquid toward the absorber 20, absorbs the refrigerant to reduce the concentration. A pump for sending the absorbed liquid from the dilute solution tank 21 to the regenerator 12, and 24 are the upstream side of the evaporator 10 and the condenser 16
Is a pressure loss member such as a capillary provided between the pressure loss member and the downstream side.

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

The above-mentioned air conditioner basically controls each container by controlling the temperature of each container except that the pump 23 is used to deliver the absorbing solution 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 and circulated by the pressure difference.

[0019]

By the way, in the above air conditioner, the lithium bromide aqueous solution used as the absorbing liquid crystallizes lithium bromide when the concentration becomes high at low temperature. If this crystallization occurs in the pipeline in the cooling cycle, the pipeline is blocked and stable operation cannot be performed.

On the other hand, the higher the average concentration of the circulating solution, the higher the cooling capacity of the air conditioner. Therefore, it is desirable to operate by circulating the solution at such a high concentration that lithium bromide does not crystallize.

The present invention has been made in view of the above points. By changing the average concentration of the absorbing liquid circulating in the cooling cycle according to the fluctuation of the outside air temperature, the crystallization of the absorbing liquid is prevented and the efficiency is improved. The purpose is to provide a good air conditioner.

[0022]

In order to achieve the above-mentioned object, the present invention stores an evaporator for evaporating a refrigerant, an absorption liquid for absorbing the refrigerant, and a refrigerant vapor evaporated in the evaporator as the absorption liquid. An absorber that absorbs, a regenerator that heats a rare absorption liquid that has absorbed refrigerant vapor to generate a refrigerant vapor and a concentrated absorption liquid, a condenser that condenses the refrigerant vapor generated in this regenerator, and a circulating refrigerant. A refrigerant tank for accumulating the refrigerant that is not circulated in order to adjust the total amount of the refrigerant tank, and a refrigerant amount detection means for detecting the refrigerant amount of the refrigerant tank, and directly cools the air in the room to be conditioned by the evaporator, In an air conditioner using an absorption refrigerator that cools air by blowing cooled air into a room through an duct, an outside air temperature detecting means for detecting an outside air temperature at a place where the air conditioner is installed, and this outside air temperature detecting means. Outside detected by And configure the air conditioner and a refrigerant amount adjusting means for adjusting the refrigerant amount of the refrigerant tank according to temperature.

[0023]

With the above arrangement, the refrigerant amount adjusting means adjusts the refrigerant amount in the refrigerant tank based on the temperature detected by the outside air temperature detecting means.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.

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

Since the structure of the air conditioner according to the present invention is the same as that shown in FIG. 7, the description thereof will be omitted, but an electric circuit necessary for controlling 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 temperature of the blown air, T3 is a sensor for detecting the liquid level of the regenerator, and T4 is for detecting the temperature of the condenser. Sensor, T5 is a sensor for detecting the outdoor temperature, and T6 is a sensor for detecting the amount of refrigerant in the refrigerant tank.

A controller 30 including a CPU, a memory, and a drive circuit, and a communication controller that receives a setting signal from the remote controller 6 (see FIG. 8) at the receiver 2a of the indoor unit 2 and receives a signal from the receiver 2a. 31 is provided, and the controller 30 uses the sensors T1, T2, T3, T4, T
5, the signal from T6 and the signal from the communication controller 31 are received, and the blower fan 11, the air cooling fan 17, the pump 23,
The operation of the fuel supply control valve 15 of the fuel supply pipe 14 is controlled.

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

Before the start of operation, the valves V1, V3 and V5 are closed and the valves V2 and V4 are open. All the absorbing liquid is contained 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 V are opened.
4 is closed (F-1), the motor M ₂ is driven and the pump 2
The absorption liquid is sent from the dilute solution tank 21 to the regenerator 12 by 3 (F-2). At this time, the CP of the controller 30
U determines the liquid level of the regenerator 12 has reached a specified level by looking at the signal from the sensor T3 (F-3).
When the liquid level reaches the specified level, the fuel supply control valve 1
5 is opened and fuel gas is supplied from the fuel supply pipe 14 to ignite the burner 13 (F-4).

Refrigerant vapor is generated in the regenerator 12 and the condenser 16
The temperature of the condenser 16 gradually rises due to the temperature of the refrigerant vapor. The CPU of the controller 30 determines from the signal from the sensor T4 whether the temperature of the condenser 16 has reached a predetermined value (F-5), and when it reaches the predetermined value, the air-cooling fan 17 is rotated (F- 6).

In the condenser 16, the vapor refrigerant sent from the regenerator 12 is liquefied, and this liquefied refrigerant flows into the refrigerant tank 18 via the valve V5. At this time, the CPU of the controller 30 looks at the signal from the sensor T6 and determines whether the refrigerant in the refrigerant tank 18 has reached a predetermined amount (F-
7) When the predetermined value is reached, the valve V5 is closed (F-
8) Rotate the blower fan 11 (F-9).

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

In this cooling operation, the refrigerant vaporized in the evaporator 10 to become vapor flows into the absorber 20 where it is absorbed by the absorbing liquid. The absorbing liquid, which has absorbed the refrigerant and becomes low in concentration, once enters the dilute solution tank 21 and is then pumped by the pump
As a result, the heat is exchanged with the high-concentration high-temperature absorption liquid sent from the regenerator 12 by the heat exchanger 22 through the valve V3, and is sent to the regenerator 12. This state is the steady mode of operation.

Examples of the temperature and pressure of the container, the absorbing liquid, and the refrigerant in each part of the system during the cooling operation are as follows.

Temperature (° C.) Pressure (Torr) Evaporator 10:10 to 20 10 to 20 Regenerator 12: 60 to 90 90 to 110 Condenser 16: 50 to 80 90 to 110 Absorber 20: 45 to 50 11 Refrigerant tank 18: 30-50 50-40 50 Dilute solution tank 21: 40-60 11 Heat exchanger 22: 30-90-Intake duct 4: 26 (room temperature) -Blower duct 3: 13-20- 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), stop processing is performed (F-12), and then the processing ends. As the stop processing, first, the burner 13 is extinguished, and the valve V2,
Open V4 and close valve V1. Then, 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 are absorbed by the absorbing liquid while the device is stopped.
This is to prevent 2 from corroding and diluting the concentrated solution to prevent crystallization.

Next, the control for changing the average concentration of the absorbing liquid in the cooling cycle with respect to the change of the outside temperature will be described.

FIG. 3 is a diagram for explaining the timing of lowering the average concentration of the absorbing liquid.

FIG. 3 shows a case where the outside air temperature drops sharply. In the figure, t1 is the temperature at which the absorption liquid may crystallize when the outside air temperature falls below the current average concentration of the absorption liquid. However, in actual driving,
If t1 is reached with the current average concentration of the absorbing liquid, the absorbing liquid may crystallize. Therefore, the timing for lowering the concentration of the absorbing liquid must be set to a temperature higher than t1. . t2 is the temperature at the timing of lowering the concentration of this absorbing liquid. In addition, when the outside air temperature sharply drops, it may not be in time even if the concentration of the absorbing liquid is lowered when the outside air temperature reaches t2. Therefore,
Even if the temperature is higher than t2, it is necessary to reduce the concentration of the absorbing liquid when the outside air temperature suddenly drops. t3 is the temperature at the timing of lowering the concentration of the absorbing liquid when the outside air temperature sharply drops.

Now, in FIG. 3, when the outside air temperature begins to drop sharply at a point A with a descending gradient of a predetermined value or more and reaches a temperature t3 at a time m1, the valve V4 is opened for a predetermined time from the time m1 to open the refrigerant tank. A predetermined amount of the refrigerant in 18 is flown into the dilute solution tank 21 to reduce the average concentration of the absorbing liquid in the cooling cycle.

FIG. 4 is a diagram for explaining another timing for lowering the average concentration of the absorbing liquid, which is t1, t2, t in the figure.
3 is the same as that shown in FIG. FIG. 4 shows a case where the outside air temperature gradually decreases.

The outside air temperature gradually falls and at time m2 the temperature t
When it reaches 2, the valve V4 is opened for a predetermined time from the time point m2, and a predetermined amount of the refrigerant in the refrigerant tank 18 is caused to flow into the dilute solution tank 21 to reduce the average concentration of the absorbing liquid in the cooling cycle.

FIG. 5 is a diagram for explaining the timing of increasing the average concentration of the absorbing liquid. Temperatures t1, t2, t in the figure
No. 3 is the same as that shown in FIG. The temperature t4 is set higher than the temperature t3, the outside air temperature is unlikely to reach t1, and even if the concentration is higher than the current average concentration of the absorbing liquid, the absorbing liquid is less likely to be crystallized, but rather high concentration. It is a temperature that allows efficient operation.

As shown in FIG. 5, the outside air temperature rises and time m3
When the temperature reaches the temperature t4 at this time, the valve V5 is opened for a predetermined time from this time point m3 so that the refrigerant from the condenser 16 is accumulated in the refrigerant tank 18 and the refrigerant in the refrigerant tank 18 is increased by a predetermined amount to absorb the absorption liquid in the cooling cycle. Increase the average concentration of.

The temperatures t1 and t described with reference to FIGS. 3, 4 and 5.
2, t3, and t4 are determined in advance for each average concentration of the absorbing liquid, that is, for each refrigerant amount in the refrigerant tank 18, and are stored in the memory of the controller 30. Further, the predetermined value of the steep descending gradient of the outside temperature at the timing described with reference to FIG. 3 is also predetermined and stored in the memory of the controller 30. The predetermined value of the steep falling gradient of the outside air temperature may be set to a different value depending on the average concentration of the absorbing liquid, or may be set to the same value regardless of the average concentration of the absorbing liquid.

FIG. 6 is a flowchart of the average concentration changing process of the absorbing liquid, which is performed in the cooling operation of the air conditioner.

During the cooling operation of step (F-10) in FIG. 2, the processing for changing the average concentration of the absorbing liquid as described in FIGS. 3, 4 and 5 is performed.

First, FIG. 3 showing the current average concentration of the absorption liquid,
The temperatures t1, t2, t3, and t4 described in FIGS. 4 and 5 are read from the memory of the controller 30 (S-1).
The average concentration of the absorption liquid is higher than the concentration of the absorption liquid currently stored in the dilute solution tank 21 before the operation of the air conditioner by subtracting the amount of refrigerant currently stored in the refrigerant tank 18. Is required from that.

Next, the outside air temperature detected by the sensor T5 is t2.
It is determined whether it is the following (S-2). If the outside air temperature is t2 or lower, the average concentration of the absorbing liquid is lowered by opening the valve V4 for a predetermined time (S-6), and the process returns to step (S-1).

If the outside air temperature is not lower than t2, then it is judged whether or not the outside air temperature is lower than t3 (S-3). Outside temperature is t
If it is 3 or less, it is determined whether or not the descending slope until the outside air temperature reaches t3 is a predetermined value or more (S-5). If the descending gradient is equal to or higher than the predetermined value, the average concentration of the absorbing liquid is lowered by opening the valve V4 for a predetermined time (S-6), and the step (S-
Return to 1). If not, the process returns to step (S-2).

In step (S-3), the outside air temperature is t3.
If not, it is determined whether the outside air temperature is t4 or higher (S-4). If the outside air temperature is t4 or higher, the average concentration of the absorbing liquid is increased by opening the valve V5 for a predetermined time (S-
7) and returns to step (S-1). If not, the process returns to step (S-2).

In this embodiment, an aqueous lithium bromide solution was used as the absorbing liquid and water was used as the refrigerant, but the present invention is not limited to this.

[0054]

As described above, according to the present invention,
By changing the average concentration of the absorbing liquid that circulates in the cooling cycle according to the fluctuation of the outside air temperature, it is possible to prevent the absorbing liquid from crystallizing, and to the extent that the average concentration of the circulating absorbing liquid does not crystallize. A high-concentration cooling operation with a high cooling capacity can be performed.

[Brief description of drawings]

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

FIG. 2 shows a flow chart of a steady mode of operation of an air conditioner according to the present invention.

FIG. 3 is a diagram illustrating a change in the outside air temperature and a timing for lowering the average concentration of the absorbing liquid.

FIG. 4 is a diagram illustrating another timing of showing changes in the outside air temperature and lowering the average concentration of the absorbing liquid.

FIG. 5 is a diagram illustrating a change in the outside air temperature and a timing for increasing the average concentration of the absorbing liquid.

FIG. 6 is a flowchart of an average concentration changing process of absorbing liquid, which is performed in a cooling operation of the air conditioner.

FIG. 7 is a block diagram of a main part of a modified example of an air conditioner using a single-effect absorption refrigerator proposed in the prior application.

FIG. 8 shows an installation state of the air conditioner shown in FIG.

[Explanation of symbols]

 1 Outdoor Unit 2 Indoor Unit 3 Blower Duct 4 Intake Duct 5 Room 6 Remote Controller 10 Evaporator 11 Blower Fan 12 Regenerator 13 Burner 16 Condenser 17 Air Cooling Fan 18 Refrigerant Tank 20 Absorber 21 Dilute Solution Tank 30 Controller 31 Communication Control Units T1, T2, T3, T4, T5, T6 Sensors V1, V2, V3, V4, V5 valves

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hideki Furukawa 1-21-18 Inaridai, Sakura City, Chiba Prefecture (72) Kanako Nakayama 7-39-10 Kanagawa Nakamatsu City, Chiba Prefecture

Claims (2)

[Claims] 1. An evaporator that evaporates a refrigerant, an absorber that stores an absorption liquid that absorbs the refrigerant and that absorbs the refrigerant vapor that has evaporated in the evaporator, and a rare absorption liquid that absorbs the refrigerant vapor. A regenerator that generates a refrigerant vapor and a concentrated absorption liquid, a condenser that condenses the refrigerant vapor generated in the regenerator, and a refrigerant tank that stores a refrigerant that is not circulated to adjust the total amount of the circulating refrigerant, A refrigerant amount detecting means for detecting the amount of refrigerant in the refrigerant tank is provided, and the air in the room to be conditioned is directly cooled by the evaporator, and the cooled air is blown into the room through a duct for cooling. In an air conditioner using an absorption chiller, an outside air temperature detecting means for detecting an outside air temperature at a place where the air conditioner is installed, and an amount of refrigerant in the refrigerant tank is adjusted according to the outside air temperature detected by the outside air temperature detecting means. And a refrigerant amount adjusting means An air conditioner characterized by being provided. 2. The refrigerant amount adjusting means includes a first predetermined temperature and a second predetermined temperature higher than the first predetermined temperature.
And a third predetermined temperature higher than the second predetermined temperature for each refrigerant amount in the refrigerant tank, and a predetermined descending gradient of the outside air temperature; When the outside air temperature detected by the air temperature detecting means reaches the first predetermined temperature, the amount of refrigerant in the refrigerant tank is reduced, and the outside air temperature detected by the outside air temperature detecting means reaches the second predetermined temperature. Further, when the temperature suddenly falls below the predetermined descending gradient, the amount of refrigerant in the refrigerant tank is reduced, and when the outside air temperature detected by the outside air temperature detecting means reaches the third predetermined temperature, the amount of refrigerant in the refrigerant tank. The air conditioner according to claim 1, further comprising an increasing / decreasing amount increasing unit.