JPH05272833A - Control method for freezing output of adsorption type freezer and adsorption type freezer capable of controlling freezing output - Google Patents

Abstract

(57) [Summary] [Purpose] To control the refrigeration output of an adsorption refrigerator. An adsorption refrigerating machine comprising a plurality of adsorbent heat exchangers 3 which are filled with a solid adsorbent and alternately operate as an adsorber and a regenerator, and a common condenser 11 and evaporator 10. The amount of refrigerant vapor from the evaporator to the adsorbent heat exchanger is controlled by the control valve 18 provided in the refrigerant vapor path to control the refrigeration output. [Effect] The supply temperature of cold water can be maintained substantially constant without a buffer water tank, and therefore, a large capacity buffer water tank or no buffer water tank is required. This simplifies equipment and operation. With respect to the increase in the load of the cold water system during the operation in which the refrigerating output is reduced, the refrigerating output can be rapidly increased, and it is possible to appropriately respond to a sudden load change.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adsorption type refrigerating machine for generating cold water for air conditioning and factory processes.

[0002]

2. Description of the Related Art As a conventional typical cold water generator capable of generating cold water by utilizing a heat source such as waste heat,
There are absorption refrigerators that use liquid hygroscopic agents such as lithium chloride, and adsorption refrigerators that use solid adsorbents such as silica gel, zeolite, and activated carbon.

The adsorption type refrigerator comprises a plurality of adsorbent heat exchangers which are filled with a solid adsorbent and alternately operate as an adsorber and a regenerator, and a common condenser and evaporator. While adsorbing the refrigerant vapor by the adsorbent of the adsorbent heat exchanger, hot water as a heat source for regeneration is flowed to the adsorbent heat exchanger on the other side to regenerate the adsorbent. In this adsorption type refrigerator, the capacity of the adsorbent, the time of the batch cycle,
That is, the refrigeration output changes depending on the cycle time and operating conditions, and the refrigeration output also fluctuates during each batch cycle in steady operation. Then, the freezing function is temporarily stopped at the time of switching each batch cycle.

FIG. 3 shows the fluctuation of the refrigerating output in such a batch cycle by the transition of the temperature on the cold water outlet side of the evaporator. The operation shown in FIG. 3 is to cool water at about 14 ° C. at the cold water inlet side and generate cold water at about 9 ° C. at the cold water outlet side. The solid line in the figure indicates the operation at full load. In this case, the broken line corresponds to the case where the cycle time is changed and the refrigerating output is controlled to operate during partial load, as will be described later. In this figure, the symbols T ₁ , T ₂ , T ₃ ; T ₁ ′, T ₂ ′, T ₃ ′ indicate the switching time points of each batch cycle, and the time t ₁ , t ₂ , t ₃ between each of these time points is t ₁ ′, t ₂ ′, t ₃ ′. Each cycle time.

As shown in the figure, at the time of switching the batch cycle, the refrigerating function is temporarily stopped so that the cold water temperature rises. Then, when the predetermined switching is completed and the adsorption by the regenerated adsorbent begins, the adsorption capacity is high at first,
The adsorbed amount of the refrigerant vapor, that is, the evaporated amount of the refrigerant vapor in the evaporator is large, and the cold water temperature rapidly decreases. Then, the target cold water temperature becomes lower than 9 ° C. Next, the cold water temperature gradually rises as the adsorption capacity of the adsorbent gradually decreases with the lapse of operating time, and when the end of the batch cycle is approached, the cold water temperature becomes higher than the target cold water temperature.

In order to buffer the fluctuation of the refrigerating output during such a batch cycle and make the temperature of the cold water to be supplied to the load constant, conventionally, a buffer water tank is generally provided and used.

However, when the refrigerating load decreases, that is, when the operation of the rated refrigerating output is continued without controlling the refrigerating output at the partial load, the cold water temperature at the outlet side of the evaporator continues to decrease, and the buffer Since the water temperature in the water tank gradually decreases and eventually becomes too low, the buffering function ceases to work, and therefore the cold water temperature flowing into the evaporator from the cold water load side also gradually decreases. When the temperature of the chilled water flowing into the evaporator decreases, the pressure of the refrigerant decreases, the amount of the refrigerant driven decreases, the efficiency decreases, and the evaporation temperature decreases. There is a risk of damage to the heat transfer tubes. For this reason, it is necessary to control the refrigeration output according to the load fluctuation.

By the way, since the above-mentioned absorption refrigerating machine uses a liquid as a hygroscopic agent, the refrigerating output can be easily and continuously changed according to the fluctuation of the load by changing the hygroscopic conditions such as the circulating amount and temperature of the hygroscopic liquid. In a conventional adsorption refrigerator using a solid adsorbent, the adsorbent / desorption amount of the refrigerant vapor of the adsorbent in the adsorbent heat exchanger, that is, the refrigerant driving amount, sets the temperature conditions of each part. Then, it will be fixedly decided,
It was difficult to continuously control the refrigeration output by changing the refrigerant driving amount. Therefore, conventionally, in the adsorption refrigerator, the refrigerating output is controlled according to the change of load by the following method.

The cycle time is not changed, and the temperature or flow rate of hot water as a heat source for regenerating the adsorbent is adjusted to regenerate the adsorbent to a state corresponding to the desired adsorption capacity. The cycle time is changed so that the batch cycle switching is temporarily stopped and the cycle time is extended at the time of partial load. The operating state of this method is as shown in FIG.
It is shown by a broken line in the inside. Incidentally, these methods are described in, for example, Japanese Patent Laid-Open No. 3-7859.
It is disclosed in the publication.

[0010]

As can be seen from FIG. 3, neither the method nor the method can control the fluctuation of the refrigerating output during the batch cycle, so that the buffer water tank having a large capacity and the water supply temperature control together therewith can be controlled. A water temperature control valve, etc. is necessary, and the equipment and its operation are complicated. In addition, the method requires a flow rate of hot water as a heat source for regeneration or a temperature control mechanism, which further complicates the equipment and its operation. .. The present invention is intended to solve the above problems.

[0011]

In order to solve the above-mentioned problems, first of all, the present invention is common with a plurality of adsorbent heat exchangers filled with a solid adsorbent and alternately operated as an adsorber and a regenerator. In an adsorption refrigerator composed of a condenser and an evaporator, the amount of refrigerant vapor from the evaporator to the adsorbent heat exchanger is controlled by a control valve provided in the refrigerant vapor path to control the refrigeration output. Suggest a method.

In the above control method, the refrigerant vapor amount is
It is possible to control the cold water temperature at the outlet side or the inlet side of the evaporator of the cold water system passing through the evaporator to be constant.

As a device to which the above control method is applied, a plurality of adsorbent heat exchangers filled with a solid adsorbent and alternately operated as an adsorber and a regenerator, and a common condenser and evaporator are provided. In the adsorption type refrigerating machine composed of and, a control valve having an opening / closing function and a flow rate control function is provided in the refrigerant vapor path from the evaporator to each of the adsorbent heat exchangers, and the evaporation of the cold water system passing through the evaporator is An adsorbing refrigerator having a cold water temperature sensor provided on the outlet side or the inlet side of the container and comprising control means for controlling the control valve based on the cold water temperature on the outlet side or the inlet side measured by the sensor is proposed.

[0014]

[Operation] When the adsorbent filled in the adsorbent heat exchanger that operates as an adsorber has a relatively large adsorbing capacity with respect to the load of the cold water system during operation of the refrigerator, the adsorbent is removed from the evaporator. If the amount of refrigerant vapor to the adsorbent heat exchanger is limited by the control valve, the amount of refrigerant evaporated in the evaporator can be limited, and thus the refrigeration output can be reduced.
Further, with respect to the increase in the load of the cold water system during the operation in which the refrigerating output is reduced, the refrigerating output can be rapidly increased by increasing the opening degree of the control valve.

The control of the amount of refrigerant vapor by the control valve is carried out based on the cold water temperature at the outlet side or the inlet side of the evaporator of the cold water system passing through the evaporator so that the cold water temperature is set to a desired constant value. The control of the refrigeration output can be appropriately performed according to the load of the cold water system.

[0016]

Embodiments of the present invention will now be described with reference to the drawings.
FIG. 1 is a system explanatory view showing the configuration of an embodiment of an adsorption type refrigerator to which the present invention is applied. In the figure, reference numeral 1 is a vacuum container, and this vacuum container 1 is divided by a partition plate 2.
Each of the chambers has an adsorbent heat exchanger 3a, 3a.
b is installed. The adsorbent heat exchangers 3a and 3b have a structure in which a heat transfer surface of a heat transfer tube (not shown) constituting the heat exchanger is filled with a solid adsorbent such as silica gel, and a supply pipe 4a connected to these heat transfer tubes. 4b is connected to the cooling water supply system 6 and the hot water supply system 7 via the switching mechanism 5. The switching mechanism 5 is configured using four switching valves 8a, 8b, 9a, 9c for switching the connection between the cooling water supply system 6 and the hot water supply system 7 and the supply pipes 4a, 4b leading to the adsorbent heat exchangers 3a, 3b. is doing.

Explaining the functions of these switching valves, the switching valves 8a and 8b are the forward path 6a and the return path 6b of the cooling water supply system 6, respectively, and the supply pipes 4 of the adsorbent heat exchangers 3a and 3b.
a, 4b are switched and connected, and the switching valve 9a,
9c is a configuration in which the forward path 7a and the return path 7b of the hot water supply system 7 are switched and connected to the supply pipes 4a and 4b of the adsorbent heat exchangers 3a and 3b, respectively.
When the forward path 6a and the return path 6b of the cooling water supply system 6 are connected to the supply pipe 4a (4b) of the adsorbent heat exchanger 3a (3b) on one side, the adsorbent heat exchanger 3b on the other side is connected. (3
The forward path 7a and the return path 7b of the hot water supply system 7 are connected to the supply pipe 4b (4a) of a) so as to be in a connected state.

Reference numeral 10 is an evaporator, 11 is a condenser,
The evaporator 10 and the condenser 11 are connected to the adsorbent heat exchangers 3a and 3b via refrigerant vapor paths. A heat transfer tube 13 connected to the cold water system 12 is installed in the evaporator 10, and a heat transfer tube 14 connected to the cooling water supply system 6 is installed in the condenser 11. Further, a refrigerant supply pipe 16 provided with an expansion valve 15 is installed between the condenser 11 and the evaporator 10.

A condenser 11 and respective adsorbent heat exchangers 3a,
On-off valves 17a, 17b are provided in the refrigerant vapor path between the 3b, and the evaporator 10 and the respective adsorbent heat exchangers 3a,
Control valves 18a and 18b having an opening / closing function and a flow rate control function are provided in the refrigerant vapor path between the 3b.

Reference numeral 19 is a control means, and 20 is a cold water system 12.
The cold water temperature sensor provided on the outlet side of the evaporator 10, that is, on the cold water outgoing path 12a. The control means 19 controls the opening / closing functions of the four switching valves 8a, 8b, 9a, 9c, the opening / closing valves 17a, 17b, and the control valves 18a, 18b to alternately connect the adsorbent heat exchangers 3a, 3b to adsorbers and The operation is switched to operate as a regenerator, and after switching, the flow rate control function of the control valves 18a and 18b is controlled based on the cold water temperature on the outlet side of the evaporator 10 measured by the cold water temperature sensor 20.

FIG. 1 shows an operating state of a batch cycle in which the adsorbent heat exchanger 3a is operated as an adsorber and the adsorbent heat exchanger 3b is operated as a regenerator. In this operating state, a solid line is shown in the figure. As described above, the switching valves 8a and 8b corresponding to the cooling water supply system 6 are provided on the adsorbent heat exchanger 3a side and the hot water supply system 7 side.
The switching valves 9a and 9b corresponding to No. 3 are switched to the adsorbent heat exchanger 3b side. Further, the open / close valve 17a on the side of the adsorbent heat exchanger 3a is closed and the control valve 18a is open, and the open / close valve 17b of the adsorbent heat exchanger 3b is open and the control valve 18b is closed. The on-off valve 17a and the control valve 18b which are closed are hatched in the figure.

In the above batch cycle, the adsorbent of the adsorbent heat exchanger 3b is heated by the hot water supplied from the hot water supply system 7 to the heat transfer tube through the switching valves 9a and 9b to release the refrigerant vapor. This refrigerant vapor reaches the condenser 11 through the on-off valve 17b as shown by the arrow in the figure, and the condenser 11
The cooling water of the cooling water supply system 6 flowing through the internal heat transfer tube 14 is heat-exchanged and condensed, and the condensate flows into the refrigerant supply tube 16 and is supplied to the evaporator 10 via the expansion valve 15. In this way, the adsorbent is regenerated on the adsorbent heat exchanger 3b side.

On the other hand, on the adsorbent heat exchanger 3a side, since the adsorbent is regenerated in the previous batch cycle in the same manner as described above, the refrigerant vapor in the evaporator 10 is discharged through the control valve 18a. Aspirate and adsorb. The heat of adsorption generated at this time is removed by the cooling water supplied from the cooling water supply system 6 via the switching valves 8a and 8b. Then, as described above, the refrigerant liquid supplied through the refrigerant supply pipe 16 evaporates in the evaporator 10, and at this time, the cold water system 1 flowing through the heat transfer pipe 13
Heat is taken from the cold water of 2 and cooled.

During the above batch cycle, the control valve 18
When a is kept fully open, when the load on the cold water system 12 is small, that is, when the adsorbent has a relatively high adsorbing capacity even during partial load or full load, such as immediately after switching the batch cycle. In this case, the amount of evaporation of the refrigerant in the evaporator 10 also increases, and the amount of heat taken from the cold water in the cold water system 12 also increases, so that there is a disadvantage that the cooling is performed more than necessary.

Therefore, the control means 19 monitors the chilled water temperature at the outlet side of the evaporator 10 by the chilled water temperature sensor 20 in the above operation, and this chilled water temperature is set to a set temperature, for example, 9 ° C.
The flow rate control function of the control valve 18a is controlled so that
That is, when the cold water temperature tends to be lower than the set temperature, the opening degree of the control valve 18a is reduced, and when the cold water temperature tends to be higher than the set temperature, the control valve 18b is lowered.
Increase the opening of.

By thus reducing the opening degree of the control valve 18a and limiting the amount of the refrigerant vapor flowing through the refrigerant vapor path 10a, the adsorption capacity of the adsorbent with respect to the load of the cold water system 12 as in the case described above. Therefore, the evaporation amount of the refrigerant in the evaporator 10 can be appropriately limited even in the case of a relatively large amount, and thus the refrigeration output can be appropriately controlled in accordance with the load of the cold water system.

Therefore, even when the load of the cold water system 12 is small or immediately after the batch cycle is switched, it is possible to prevent excessive cooling of the cold water. Further, by controlling the amount of the refrigerant vapor in this way, it is possible to prevent the refrigerant vapor from being excessively adsorbed to the adsorbent and to maintain the adsorption ability for a long time. Further, since it is not necessary to change the cycle time of the above batch cycle, the rated adsorption capacity of each of the adsorbent heat exchangers 3a and 3b is the same as that in the conventional normal operation, and therefore the load of the cold water system 12 is increased. in case of,
The refrigeration output can be quickly raised to the rated output as needed.

FIG. 2 shows the transition of the cold water temperature at the outlet side of the evaporator 10 when the above control operation is performed. The solid line shows the transition of the cold water temperature during full load operation, and the broken line shows the partial load. It shows the transition of the cold water temperature during the operation.

As shown in this figure, when the control operation of the present invention is applied, the chilled water temperature at the outlet side of the evaporator 10 is changed at the time of batch cycle switching in both full load operation and partial load operation. Although the temperature rises due to a temporary stop of the refrigeration function as in the conventional case, the set temperature rapidly increases thereafter.
It can be seen that the temperature drops to 0 ° C and is maintained at this set temperature thereafter. In the figure, the cold water temperature rises above the set temperature near the end of each batch cycle in full load operation, but such rise in temperature adjusts the adsorbent filling amount, cycle time, etc. This can be prevented. In this way, in the adsorption type refrigerator to which the control operation of the present invention is applied, the cold water temperature can be controlled to be constant, so that the capacity of the buffer water tank can be greatly reduced compared to the conventional one, or the buffer water tank can be eliminated altogether. It is also possible.

The control operation described above controls the refrigerating output in accordance with the load of the cold water system by keeping the cold water temperature at the outlet side of the evaporator 10 constant. Even if the cold water temperature sensor measures the temperature at the inlet side of 10 and the cold water temperature at the inlet side is kept constant, the refrigerating output can be controlled in accordance with the load of the cold water system.

The adsorption type refrigerator to which the control operation of the present invention is applied has a control valve 18 in addition to the above-described configuration shown in the drawings.
With the exception of the configurations of a and 18b, those having an appropriate configuration such as a conventional one can be used. As long as the control valves 18a and 18b have an opening / closing function and a flow rate control function, they may be configured by a single valve as shown in the figure, or may be configured by combining an on / off valve and a flow rate control valve.

[0032]

As described above, the present invention controls the refrigerating output by controlling the refrigerant vapor amount from the evaporator to the adsorbent heat exchanger by the control valve, and therefore has the following effects. It becomes possible to maintain the supply temperature of cold water almost constant without a buffer water tank, so that a large capacity buffer water tank or no buffer water tank is required. This simplifies equipment and operation. With respect to the increase in the load of the cold water system during the operation in which the refrigerating output is reduced, the refrigerating output can be rapidly increased, and it is possible to appropriately respond to a sudden load change.

[Brief description of drawings]

FIG. 1 is a system explanatory diagram showing the configuration of an embodiment of an adsorption refrigerator according to the present invention.

FIG. 2 is an explanatory diagram showing a transition of the cold water temperature on the outlet side of the evaporator of the cold water system in the operation in which the control operation of the present invention is performed.

FIG. 3 is an explanatory diagram showing a transition of the cold water temperature at the outlet side of the evaporator of the cold water system in the operation by the control operation of the conventional adsorption refrigerator.

[Explanation of symbols]

 1 Vacuum Container 2 Partition Plates 3a, 3b Adsorbent Heat Exchanger 4a, 4b Supply Pipe 5 Switching Mechanism 6 Cooling Water Supply System 7 Hot Water Supply System 8a, 8b Switching Valve 9a, 9b Switching Valve 10 Evaporator 11 Condenser 12 Cold Water System 13, 14 Heat transfer pipe 15 Expansion valve 16 Refrigerant supply pipe 17a, 17b Open / close valve 18a, 18b Control valve 19 Control means 20 Cold water temperature sensor

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hideaki Terasawa 478 Bonsai Town, Omiya City, Saitama Prefecture

Claims (5)

[Claims] 1. An adsorption refrigerating machine comprising a plurality of adsorbent heat exchangers filled with a solid adsorbent and alternately operating as an adsorber and a regenerator, and a common condenser and evaporator. Refrigerating output control method for adsorption refrigerator, characterized in that the refrigerating output is controlled by controlling the refrigerant vapor amount from the evaporator to the adsorbent heat exchanger by a control valve provided in the refrigerant vapor path. 2. The adsorption method according to claim 1, wherein the amount of the refrigerant vapor is controlled so that the cold water temperature at the outlet side of the evaporator of the cold water system passing through the evaporator is kept constant. Method for controlling refrigerating output of rotary refrigerator 3. The adsorption method according to claim 1, wherein the amount of refrigerant vapor is controlled so that the cold water temperature at the inlet side of the evaporator of the cold water system passing through the evaporator is constant. Method for controlling refrigerating output of rotary refrigerator 4. An adsorption refrigerating machine comprising a plurality of adsorbent heat exchangers filled with a solid adsorbent and alternately operating as an adsorber and a regenerator, and a common condenser and evaporator. A control valve having an opening / closing function and a flow rate control function is provided in the refrigerant vapor path from the evaporator to each of the adsorbent heat exchangers, and a cold water temperature sensor is provided at the outlet side of the evaporator in the cold water system that passes through the evaporator. An adsorption refrigerator having a control means for controlling the control valve based on the outlet-side cold water temperature measured by the sensor. 5. An adsorption refrigerator comprising a plurality of adsorbent heat exchangers filled with a solid adsorbent and alternately operating as an adsorber and a regenerator, and a common condenser and evaporator, In the refrigerant vapor path from the evaporator to each of the adsorbent heat exchanger, a control valve having an opening and closing function and a flow rate control function is provided, and a cold water system of the cold water system passing through the evaporator is provided with a cold water temperature sensor on the evaporator inlet side, An adsorption refrigerator comprising a control means for controlling the valve based on the cold water temperature on the inlet side of the evaporator measured by this sensor.