JPS6225947B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention provides a method for controlling the timing of stopping an absorption refrigerator, in particular, measuring the concentration of an absorption solution in the absorption refrigerator before stopping, and determining the relationship with this concentration. This invention relates to a method for determining an appropriate time to stop an absorption refrigerator.

[Prior art]

Conventionally, when stopping the operation of an absorption chiller (stopping the supply of heat source to the generator), the operation was stopped according to the completion time of the building's predetermined air conditioning time (end time), or when the air temperature Based on our experience, the air conditioning system stops several minutes before the end of the specified air conditioning time, and even if it stops several minutes before, the exact number of minutes before it stops depends entirely on the operator's intuition. There was no determination of stop times based on scientific numbers.

[Purpose of the invention]

In the present invention, the time required for the room temperature to reach the upper limit of the allowable room temperature range during air conditioning after the supply of heat source to the generator is stopped depends on the outside air temperature, but if the outside air temperature is constant, the room temperature at the time of the stop is In addition, considering that the concentration of the absorption solution is highly dependent on the concentration of the absorption solution, the concentration of the absorption solution should be measured and the supply of heat source to the generator should be stopped as early as possible in relation to the concentration to avoid wasteful energy consumption. The purpose is to avoid

[Structure of the invention]

Conventionally, when stopping operation of an absorption chiller, the refrigerant liquid from the evaporator side is transferred to the absorption solution side to prevent crystals from forming in the solution even if the temperature of the absorption solution drops to room temperature during the stoppage. and lowering the overall concentration of the absorption solution. Normally, the refrigerant liquid on the evaporator side that is heated and regenerated by energy such as gas in the generator would evaporate and move to the absorption solution side in the form of vapor while exerting a refrigeration effect. When the absorption chiller stops operating, the high-concentration absorbent solution is destroyed because it moves to the absorption solution side in the form of a refrigerant and dilutes the high-concentration absorbent solution as described above without exerting its freezing effect. Although it has cooling capacity, i.e., concentration energy, it ends up being completely unused.

The present invention aims to effectively utilize the concentration energy possessed by this high concentration absorption solution when stopping the absorption refrigerator and also to prevent precipitation of crystals before the heat source supply is stopped. The concentration of the absorbing solution or the concentration and the load condition are detected, the detected concentration of the absorbing solution or the concentration and the load condition, the preset concentration of the absorbing solution or the concentration and the load condition, and the heat source supply stop time. From the relationship between the time from This is a method of controlling the supply stop time of the heat source.

The relationship between the concentration of the absorption solution and the time when the supply of heat source to the generator is stopped will be explained based on FIG. 1.

When the supply of heat to the generator of an absorption _chiller that is operated under conditions such that the room temperature is The time it takes to reach T ₁ depends on the building's thermal capacity, cold (hot) water piping capacity, and other factors. However, since the heat capacity of the building is constant, the factors that affect the time it takes to reach T ₁ are the room temperature at the time of stopping the supply of heat source to the generator of the absorption chiller, the outside temperature, and the temperature of the absorption solution. There is concentration. Although the influence of the temperature of the absorption solution may be considered, there is almost no difference in temperature depending on the operating conditions, so the difference in temperature of the absorption solution can be ignored. In other words, if the room temperature immediately before the supply of heat source is stopped is T and the outside temperature is the same, then the change in room temperature when the concentration of the absorbing solution is C ₁ immediately before the time T _S when supply of the heat source to the generator is stopped is If the concentration of the solution is _C2 , which _is higher than _C1 , then the change in room temperature will be shown by line _l2 .
That is, if the concentration of the absorption solution is high before the supply of heat source to the generator is stopped, the temperature is at the upper limit of the room temperature tolerance range after the supply of heat source to the generator is stopped.
The time required to reach T ₁ is longer than when the concentration of the absorption solution is low. That is, the higher the concentration of the absorption solution, the higher the concentration energy. For example, if the room temperature before stopping the operation of the absorption refrigerator is T and the outside temperature is the same, when the concentration of the absorption solution is C ₁ , the indoor temperature will be T ₁ in △T minutes after the supply of heat source to the generator is stopped.
However, when the concentration of the absorption solution is C ₂ (△
T + △T ₁ ) minutes later, the room temperature becomes T _1. Therefore, when the concentration of the absorption solution is C ₁ , the concentration of the absorption solution is C 1 at △T minutes before the end of the workday, and when the concentration of the absorption solution is C ₂ , the temperature becomes T _1.
If the heat source supply to the generator is stopped △T ₁ minute earlier than when the work day ends, that is, △T + △T ₁ minutes before the end of the work day, the room temperature will be the upper limit of the allowable room temperature range at the end of the work day.
T ₁ , and wasteful energy consumption can be prevented.

The value of △T or △T + △T ₁ is determined by calculating the cooling capacity that can be released from the concentrated energy stored in the absorption solution before stopping, and calculating the number of minutes after the heat source stops based on the air conditioning load at that time. It is possible to calculate the degree to which air conditioning is possible, but when an absorption refrigerator is installed to air condition a certain room, the relationship between this time and the concentration of absorption solution under various load conditions must be tested in advance. You can also ask for it. From these results, if we assume that the shortest time among the times determined for a specific absorption solution concentration is ΔT for that concentration, then
By simply measuring the concentration, it is possible to know how many minutes before the end of the specified air conditioning the heat source supply should be stopped, making it possible to stop the heat source earlier than when relying on conventional methods. Therefore, energy can be saved. Furthermore, if the stop time is controlled based on both of the load conditions (for example, outside temperature and room temperature) in addition to the concentration of the absorbing solution, more detailed or effective control becomes possible. That is, when determining the concentration of the absorption solution under various load conditions and the air conditioning available time △T after the heat source is stopped, when the concentration of the absorption solution is the same, when the outside temperature is T ₂ , △T is X ₂ minutes,
Suppose that ΔT is X ₃ minutes when the outside temperature is higher than that, T ₃ . In this case, X ₃ is shorter, but if the heat source stop time is controlled using only the concentration of the absorbing solution as an index, it will be possible to prevent the room temperature from rising above the room temperature allowable range before the end of the specified air conditioning under any load. Therefore, the heat source supply must be stopped before X ₃ minutes, which is the time when the outside temperature is high. When controlling the stop time, if the outside temperature is T ₃ , the stop time is X ₃ before the end of the specified air conditioning.
The heat source supply can be stopped before the outside temperature reaches T ₂
In this case, it is only necessary to stop the heat source supply before X ₂ minutes, which allows for more precise control.

Figure 2 is for explaining the location and method of measuring the concentration of the absorption solution in the present invention, where GH is a high temperature generator, GL is a low temperature generator, C is a condenser, A is an absorber, and E is a In the evaporator, L ₁ is an absorber liquid level detector, L ₂ is an evaporator liquid level detector, 1 is an absorption solution withdrawal pipe from the absorber, and 2 is a concentrated absorption solution supply pipe to the absorber.

In the apparatus shown in FIG. 2, the concentration of the absorption solution may be detected at either the outlet section 1 of the absorber A or the concentrated solution outlet section 2 of the absorption solution heat exchanger. The concentration of the absorption solution can be easily determined by a conventional method from the temperature and specific gravity of the absorption solution. The temperature can be determined using a normal temperature sensor such as a thermocouple or a resistance temperature detector, and the specific gravity can be determined using a buoyancy meter, an α-ray densitometer, or a vibrating specific gravity meter. Alternatively, the concentration of the absorption solution can be determined by measuring the amount of separated refrigerant liquid using the liquid level detector _L2 of the evaporator, and estimating the average concentration of the absorption solution based on this amount. It can also be determined by measuring the amount of absorption solution in the absorber using the absorber liquid level detector _L1 . It is also possible to estimate the absorption solution concentration from the generator outlet solution temperature and condensation temperature.

Next, an embodiment of the present invention will be described based on FIG.

In Figure 3, the symbols GH, GL, C, A, E, 1
and 2 have the same meaning as shown in FIG.
3 is a cold water pump, 4 is an air conditioner, 5 is a fan, 6 is a building, 7 is a controller, 8 is a room temperature sensor, 9
is an outside temperature sensor, 10 is a concentration detection sensor, 1
1 is a refrigerator control panel, 12 is a stop signal, 13 is a duct (outward), and 14 is a duct (return).

The controller 7 has each sensor 8, 9, 10
The system receives signals from the refrigerator, performs calculations, and determines the time at which the refrigerator should be stopped. Then, when the stop time comes, the controller 7 sends a message to the refrigerator control panel 11.
A stop signal 12 is sent to stop the refrigerator, or when the stop time is reached, a buzzer or other device is used to notify the operator that the stop time has arrived. The controller 7 may be built into the control panel or may be installed separately. Room temperature may be measured at one location, but preferably at multiple locations. In this case, the average value for each room may be used, or
The highest value may be used.

Not only when one refrigerator is installed,
It is also possible to have multiple units installed.

〔Effect of the invention〕

In the present invention, by measuring the concentration of the absorption solution, the heat source supply to the absorption refrigerator can be stopped in accordance with the concentration or earlier than conventionally due to the relationship between the concentration and the load. Since the concentration energy possessed by the absorbing solution can be effectively used, it is possible to save the heat amount of the heat source and the power cost.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the relationship between the concentration of the absorption solution and the time it takes for the room temperature to reach the upper limit of the allowable room temperature range after the supply of heat source to the absorption refrigerator is stopped.
3 and 3 are diagrams showing one embodiment of the present invention. T...Room temperature, T _p ...Lower limit of room temperature tolerance, T ₁
... Upper limit of room temperature allowable range, T _S ... Heat source supply stop time, T _L , T _H ... Time when room temperature reaches the upper limit of room temperature allowable range, GH... High temperature generator, GL... Low temperature generator, C...Condenser, A...Absorber, E...Evaporator, _L1 ...Absorber solution level detector, _L2 ...Evaporator refrigerant level detector, 1...Absorption solution draw-out pipe, 2... ...Absorption solution supply pipe, 3...Cold water pump,
4... Air conditioner, 5... Fan, 6... Building, 7...
...Controller, 8...Room temperature sensor, 9...
Outside temperature sensor, 10...Solution concentration sensor, 1
1... Refrigerator control panel, 12... Stop signal, 13...
...Duct (outward), 14...Duct (return).

Claims (1)

[Claims] 1. In an absorption refrigerator whose operation is started and stopped according to the usage time, the concentration of an absorption solution before the heat source supply is stopped is detected, and the detected concentration of the absorption solution is combined with a preset value. From the relationship between the concentration of the absorbing solution and the time from the time the heat source supply is stopped until the room temperature reaches the upper limit of the room temperature tolerance range, find the time until the room temperature reaches the upper limit of the room temperature tolerance range after the heat source supply is stopped. , a method of controlling the supply stop time of the heat source of the absorption chiller based on this determined time. 2. Detect the concentration and load conditions of the absorption solution before the supply of the heat source is stopped, and based on the detected concentration and load conditions, set the concentration and load conditions of the absorption solution in advance and the room temperature from the time when the supply of the heat source is stopped. In relation to the time it takes to reach the upper limit of the tolerance range,
Claim 1 requires the time required for the room temperature to reach the upper limit of the room temperature tolerance range after the supply of the heat source is stopped.
A method for controlling the supply stop time of a heat source of an absorption refrigerator as described above.