JP4321318B2 - Triple effect absorption refrigerator - Google Patents

Description

  The present invention relates to a triple effect absorption refrigerator suitable for performing stable operation at the start of cooling operation and improving operating efficiency.

  Triple-effect absorption refrigerators (sometimes called triple-effect machines) equipped with high-temperature regenerators, medium-temperature regenerators, and low-temperature regenerators (sometimes referred to as triple-effect regenerators) This is superior to the double effect machine in that the heat generated by heating the dilute solution in the high temperature regenerator is effectively used in the regenerator in the downstream. However, during cooling operation, the pressure in the high-temperature regenerator of the triple effect machine is considerably higher than the pressure in the high-temperature regenerator of the double effect machine, while the flow rate of the rare solution operating in the triple effect machine is the same as that of the double effect machine. In order to be equivalent, the triple effect machine requires a pump with a higher lift than the double effect machine as a pump for returning the dilute solution from the absorber to the high temperature regenerator.

A conventional triple effect machine will be described by borrowing FIGS. 1, 2 and 3 illustrating the triple effect machine of the present invention. The conventional triple effect machine employs one high-lift pump as a feeding means (SP1 and SP2 in FIG. 1) for returning the diluted solution from the absorber 7 to the high-temperature regenerator 2 in the equipment configuration shown in FIG. It was. However, high head pumps are less efficient than low head pumps used in double effect machines. The high-lift pump is shown as “Prior art pump” in FIG. 2, and the low-lift pump used in the dual effect machine is equivalent to the one shown as “One of the present invention alone” in the figure. It can be seen from FIG. 2 that the efficiency of the high head pump is lower than that of the low head pump at the rated flow rate of the absorption chiller.
In the absorption chiller, the pump is inverter controlled based on the pressure of the high temperature regenerator. As shown in FIG. 3, the characteristics of the high head type pump are the fluctuation of the head with respect to the fluctuation range of a certain frequency. The width is larger than the low head type pump. This characteristic causes an increase in the fluctuation range of the solution flow rate.

  Therefore, in the conventional triple effect machine, when the pressure fluctuation of the high temperature regenerator is large as at the start of operation, the pump frequency frequently changes and a stable solution flow rate cannot be obtained. As a result, it took a long time to start cooling. In addition, because the specifications of the high-lift pump have high output, its power consumption is much higher than that of the double-effect machine.

As an example of a conventional double-effect absorption refrigerator, among the high-temperature refrigerant vapor and the intermediate concentrated solution generated in the high-temperature regenerator, the intermediate concentrated solution is sent to the absorber and cooled here, and the intermediate concentrated solution is converted into the evaporator. The refrigerant vapor evaporated in step 1 is absorbed, and the dilute solution in the absorber is sent to the low temperature regenerator by one pump through the pipe, and returned to the high temperature regenerator by another pump through the pipe branched in the middle. There is something.
(For example, see Patent Document 1).

JP-A-7-269978

  As described above, in the conventional triple effect absorption refrigerator, a high head type pump is used to return the diluted solution from the absorber to the high temperature regenerator. When the triple effector starts up, a large pressure fluctuation occurs in the high-temperature regenerator, the frequency applied to the high-lift pump frequently fluctuates, and a stable flow rate cannot be obtained. There was a problem that it took a long time. In addition, since the high head type pump has a high output, its power consumption is much higher than that of the double effect machine.

  The subject of this invention is providing the triple effect absorption refrigerating machine which implement | achieves efficient operation | movement while performing the start-up of cooling operation | movement smoothly.

In order to solve the above problems, the triple effect absorption refrigerator of the present invention is a dilute solution from a high temperature regenerator, a medium temperature regenerator, a low temperature regenerator, a condenser, an evaporator, an absorber and an absorber for cooling operation. This is a triple effect absorption refrigerator equipped with a feeding means for returning the water to the high temperature regenerator. The dilute solution feeding means is a series connection of two pumps controlled by an inverter based on the pressure in the high temperature regenerator. These two pumps have a total head corresponding to the generated pressure in the high-temperature regenerator during the rated capacity operation of the cooling unit, and at the start of the cooling operation, The first pump disposed upstream of the pump is operated, and when the head of the first pump reaches a predetermined value near the total head of the first pump, the spiral type disposed downstream of the first pump The second pump is operated.

Further, another triple effect absorption refrigerator of the present invention includes a high temperature regenerator that heats a dilute solution to generate a high-temperature refrigerant vapor and an intermediate concentrated solution, and a high-temperature refrigerant vapor from the high-temperature regenerator from the high-temperature regenerator. The intermediate temperature regenerator that heats the intermediate concentrated solution to generate the high temperature refrigerant vapor, and the intermediate concentrated solution from the intermediate temperature regenerator is heated by the high temperature refrigerant vapor from the intermediate temperature regenerator to generate the high temperature refrigerant vapor. A low-temperature regenerator with a concentrated solution, a condenser that cools the high-temperature refrigerant vapor from the low-temperature regenerator to form a refrigerant liquid, and evaporates the refrigerant liquid from the condenser to form a low-temperature refrigerant vapor. An evaporator that cools the secondary refrigerant for cooling, an absorber that cools the concentrated solution from the low-temperature regenerator, and absorbs the low-temperature refrigerant vapor from the evaporator into the concentrated solution to form a diluted solution, and the absorber Means to return the dilute solution inside to the high temperature regenerator It is a triple effect absorption refrigerating machine, and the dilute solution feeding means comprises two pumps connected in series with inverters based on the pressure in the high-temperature regenerator, and these two pumps are The total of the total heads has a total head corresponding to the pressure generated in the high-temperature regenerator during the cooling rated capacity operation, and is first arranged upstream of the two pumps when the cooling operation is started. One pump is operated, and when the first pump reaches a predetermined value near the total head of the first pump, a spiral second pump disposed downstream of the first pump is operated. To do. In the triple effect absorption refrigerator and another triple effect absorption refrigerator of the present invention, it is preferable that the first pump and the second pump are spiral pumps of the same model.

  As described above, by using the two pumps of the first pump and the second pump connected in series as the dilute solution feeding means, in response to the pressure fluctuation generated in the high temperature regenerator when starting the cooling operation, Since the head of the feeding means can be finely controlled, the start-up operation can be stabilized. That is, as the pressure in the high-temperature regenerator rises from the initial pressure, the first pump controls from the lowest frequency to almost the highest frequency until the head reaches a predetermined value, and after that, the second pump To the highest frequency within the range of the maximum frequency in the high-temperature regenerator at the rated output of the triple effect absorption refrigerator at the head of the two pumps. On the other hand, when a single high-lift pump is used as the dilute solution feeding means as in the prior art, the high-lift pump is operated while the pressure in the high-temperature regenerator rises from the initial pressure to the maximum pressure. Or it is controlled from the same lowest frequency as the second pump to the highest frequency. Roughly speaking, the two pumps, the first pump and the second pump, can control the head with twice the accuracy of the high head pump, which suppresses the flow fluctuation of the dilute solution caused by the pressure fluctuation in the high temperature regenerator. , Stabilize the start-up operation. In addition, since the first pump 1 is activated when the cold operation is started and the second pump is activated when the pressure in the high-temperature regenerator rises to a predetermined value, the power consumption is higher than that of a conventional high head pump. Can be reduced.

According to the present invention, two pumps are used to return the dilute solution from the absorber to the high temperature regenerator, and the two pumps are sequentially operated in response to the pressure of the high temperature regenerator,
It is possible to provide a triple effect absorption refrigerator that smoothly starts cooling operation and realizes efficient operation.

  Hereinafter, embodiments of a triple effect absorption refrigerator to which the present invention is applied will be described with reference to the drawings. FIG. 1 is a configuration diagram of a triple effect absorption refrigerator according to an embodiment of the present invention, and FIG. 2 shows conventional H (lift) -Q (flow rate) characteristics of a low head pump used in the triple effect absorption refrigerator of the embodiment. FIG. 3 is a diagram showing the frequency characteristics of a low-lift pump in comparison with a conventional high-lift pump, and FIG. 4 is a low-head pump with two units connected in series. FIG. 5 is a control flow chart of two low-head pumps connected in series in the triple effect absorption refrigerator of the embodiment.

  As shown in FIG. 1, the triple effect absorption refrigerator 1 (sometimes referred to as refrigerator 1) of the present embodiment, in order to perform a cooling operation, roughly performs a dilute solution in which a refrigerant is absorbed in an absorbent. Triple effect high-temperature regenerator 2, medium-temperature regenerator 3 and low-temperature regenerator 4 that generate high-temperature refrigerant vapor by heating, respectively, and condensation of the high-temperature refrigerant vapor supplied from the low-temperature regenerator 4 to form a refrigerant liquid 5, an evaporator 6 that evaporates the refrigerant liquid from the condenser 5 into low-temperature refrigerant vapor, absorbs heat from the secondary refrigerant that is circulated for air conditioning, and lowers the temperature of the secondary refrigerant, and a low-temperature regenerator 4, an absorber 7 that introduces the remaining concentrated solution in which refrigerant vapor is generated and absorbs the low-temperature refrigerant vapor from the evaporator 6 into the concentrated solution to generate a diluted solution, and a diluted solution in the absorber 7 as a feeding means. A first pump SP1 and a second pump SP2 connected in series for returning the solution to the high temperature regenerator 2; While the dilute solution returns from the absorber 7 to the high temperature regenerator 2, a low temperature solution heat exchanger 10, an exhaust gas heat exchanger 13, an intermediate temperature solution heat exchanger 11, and a high temperature solution heat exchanger 12 that preheat the dilute solution sequentially A refrigerant drain heat exchanger that introduces a part of the dilute solution sent from the first and second pumps SP1 and SP2 and cools the high-temperature refrigerant vapor sent from the low-temperature generator 4 to the condenser 5 in the middle thereof. 14 and a control device 16 that performs inverter control of the first and second pumps SP1 and SP2 based on the internal pressure P of the high-temperature regenerator 2. The second pump SP2 is disposed on the outlet (downstream) side of the first pump SP1. In addition, as a device that operates only during the heating operation, a heating switching valve 23 provided in a pipe for supplying the high-temperature steam generated in the high-temperature regenerator 2 directly to the evaporator 6 and an intermediate concentrated solution from the intermediate-temperature regenerator 3 are used. And a heating switching valve 24 provided in a pipe to be fed to the absorber 7. These heating switching valves 23 and 24 are opened during heating operation and closed during cooling operation.

  Next, the triple effect absorption refrigerator 1 will be described in further detail with respect to the configuration and the operation during cooling operation. The high temperature regenerator 2 is provided with a burner (not shown) so as to be immersed in a dilute solution stored therein, and the burner burns fuel to heat the dilute solution. The high-temperature refrigerant vapor heated by the high-temperature regenerator 2 and evaporated from the dilute solution is sent from the high-temperature regenerator 2 through the pipe 25 to the heat transfer pipe 18 installed in the intermediate-temperature regenerator 3, and the remaining refrigerant vapor is evaporated. The intermediate concentrated solution is sent into the intermediate temperature regenerator 3 through the pipe 30 and the high temperature solution heat exchanger 12 provided in the pipe 30.

  In the intermediate temperature regenerator 3, the intermediate concentrated solution from the high temperature regenerator 2 is heated by the heat transfer pipe 18 that flows the high temperature refrigerant vapor from the high temperature regenerator 2 to generate refrigerant vapor. The refrigerant vapor merges with the high-temperature refrigerant vapor flowing out from the heat transfer pipe 18 through the pipe 27, and is sent to the heat transfer pipe 19 installed in the low-temperature regenerator 4 through the pipe 26, while the intermediate concentrated solution in the intermediate temperature regenerator 3. Is sent to the low temperature regenerator 4 through the pipe 31 and the intermediate temperature solution heat exchanger 11 provided in the pipe 31.

  In the low temperature regenerator 4, the intermediate concentrated solution from the intermediate temperature regenerator 3 is heated by the heat transfer pipe 19 through which the refrigerant vapor from the intermediate temperature regenerator 3 flows, generating a refrigerant vapor to become a concentrated solution. The refrigerant vapor generated here flows into the condenser 5 from the opening above the partition wall 40 that defines the low temperature regenerator 4 and the condenser 5, and the high temperature refrigerant vapor in the heat transfer pipe 19 is sent through the pipe 28. On the way, the refrigerant is cooled by a refrigerant drain heat exchanger 14 (described later) and supplied to the condenser 5. On the other hand, the concentrated solution in the low temperature regenerator 4 is sent into the absorber 7 through the pipe 32 and the low temperature solution heat exchanger 10 provided in the pipe 40.

  A heat transfer tube 20 through which cooling water flows is installed in the condenser 5. In the condenser 5, the refrigerant vapor supplied from the low-temperature regenerator 4 through the refrigerant drain heat exchanger 14 and the refrigerant vapor flowing in through the partition wall 40 between the low-temperature regenerator 4 and the condenser 5 flow through the cooling water. The refrigerant is cooled by the heat transfer tube 20 to become a refrigerant liquid, and the refrigerant liquid is supplied from the condenser 5 to the evaporator 6 through the pipe 29. Here, the cooling water flowing through the heat transfer tube 20 flows out to a cooling tower (not shown).

  A heat transfer tube 21 through which a secondary refrigerant used for cooling is installed is installed in the evaporator 6. The refrigerant liquid from the condenser 5 is dispersed on the heat transfer pipe 21 and evaporated to become low-temperature refrigerant vapor. At that time, latent heat is taken away from the secondary refrigerant in the heat transfer pipe 21 to produce a low-temperature secondary refrigerant. The secondary refrigerant circulates between the evaporator 6 and the air conditioner for cooling, and is provided for cooling. The evaporator 6 communicates with the absorber 7 so that the low-temperature refrigerant vapor can flow therethrough.

  A heat transfer tube 22 through which cooling water flows is installed in the absorber 7. The concentrated solution sent from the low temperature regenerator 4 is sprayed on the heat transfer tube 22 and cooled by the cooling water in the heat transfer tube 22. The cooled concentrated solution absorbs the low-temperature refrigerant vapor transferred from the evaporator 6 to become a diluted solution and accumulates in the absorber 7. The cooling water flowing through the heat transfer tube 22 in the absorber 7 is supplied from the above-described cooling tower so as to return to the cooling tower from the heat transfer tube 22 through the pipe 33 and the heat transfer tube 21 in the condenser 5. It is circulating.

  The dilute solution accumulated in the absorber 7 is returned to the high temperature regenerator 2 through the return pipe 35 by the two pumps SP1 and SP2 provided in series with the pipe 35. In this returning process, the dilute solution is heated by the concentrated solution sent from the condenser 5 to the absorber 7 in the low-temperature solution heat exchanger 10, and then the exhaust of the burner installed in the high-temperature regenerator 2 is sequentially discharged. The high temperature solution heat exchanger 12 is further heated by the exhaust gas heat exchanger 13 provided in the exhaust gas pipe 37 to be discharged, and then by the intermediate concentrated solution sent from the intermediate temperature regenerator 3 to the low temperature regenerator 4 by the intermediate temperature solution heat exchanger 11. The intermediate concentrated solution sent from the high-temperature regenerator 2 to the intermediate-temperature regenerator 3 is heated and heated to return to the high-temperature regenerator 2. Further, the dilute solution exiting from the absorber 7 is diverted at the outlet side of the second pump SP2 on the downstream side and is partially sent to the refrigerant drain heat exchanger 14 through the pipe 36. The heat exchanger 14 passes the condenser from the low temperature regenerator 4 to the condenser. The concentrated solution sent to 5 is heat-exchanged to cool the concentrated solution, and then flows into the low temperature regenerator 4. Further, the dilute solution in the return pipe 35 is diverted between the low temperature solution heat exchanger 10 and the exhaust gas heat exchanger 13 and is partially sent to the low temperature regenerator 4 through the pipe 37, and also in the medium temperature solution heat exchanger 11 and the high temperature. The flow is divided between the solution heat exchanger 12 and sent to the intermediate temperature regenerator 3 through the pipe 38.

  The first and second pumps connected in series, which is a feature of the present invention, will be described. The first pump SP1 and the second pump SP2 are inverter-controlled canned motor type centrifugal pumps, each having a solution discharge amount (rated flow rate) necessary for the rated output operation of the refrigerator 1. The total of the total heads of the first pump SP1 and the second pump SP2 corresponds to the internal pressure of the high-temperature regenerator 2 during the rated output operation of the refrigerator 1. Here, the two pumps are operated with the same specifications, ie, the same head and the same flow rate at the same frequency. Note that the two pumps do not necessarily have the same specifications, and those having similar specifications may be combined.

  As shown in FIG. 2, each of the first pump SP1 and the second pump SP2 (indicated as “single SP1” in FIG. 2) is higher than the conventional high head pump at the rated flow rate at the rated output of the refrigerator 1. It can be seen that the pump efficiency is high.

  Further, as shown in FIG. 3, the first pump SP1 and the second pump SP2 (shown as SP (1 unit) in FIG. 3) are controlled at the set minimum frequency and the set maximum frequency, respectively. Since the internal pressure of the high-temperature regenerator 2 has risen above the pump head of the set minimum frequency, the frequency applied to the pump SP1 from the control first device 16 increases as the internal pressure of the high-temperature regenerator 2 increases, and the pump head Becomes higher. The conventional high head pump shown for comparison is controlled at the set minimum frequency to the set maximum frequency in the same manner as the low head pump. When the internal pressure of the high-temperature regenerator reaches the lift at the set minimum frequency of the high-lift pump, the high-lift pump has a higher lift than the low-lift first pump SP1 already operated at the set maximum frequency. Driven. Further, when the frequency changes by a certain range (for example, 10 Hz), the change in the head of the high head type pump is large, and the change in the head of the low head type pumps SP1 and SP2 is small. The roughness of this control is the cause of instability at the start-up in the conventional triple effect absorption refrigeration using one high head type pump.

Next, with reference to FIG. 4, the control of two low-head pumps connected in series, that is, SP1 and SP2 in the triple effect absorption refrigeration according to the embodiment of the present invention will be described.
The first pump SP1 and the second pump SP2 are individually inverter-controlled by the control device 16 based on the signal from the pressure gauge 15 that detects the pressure P of the high-temperature regenerator. First, since the pressure of the high-temperature regenerator 2 is equal to or lower than the atmospheric pressure at the beginning of the start-up of the refrigerator, only the first pump SP1 is operated at the set minimum frequency. When the pressure of the high-temperature regenerator 2 becomes equal to or higher than the head at the set minimum frequency of the first pump SP1, the control device 16 increases the frequency to operate the first pump SP1 as the pressure of the high-temperature regenerator 2 increases, thereby operating the first pump The head of SP1 is made to correspond to the pressure of the high temperature regenerator 2. When the pressure of the high-temperature regenerator 2 reaches a predetermined value close to the pressure corresponding to the total head of the first pump SP1, the operation of the second pump SP2 is started at the set minimum frequency. When the pressure of the high-temperature regenerator 2 becomes equal to or higher than the total head at the set maximum frequency of the first pump SP1, the first pump SP1 continues operating in that state and the frequency to the second pump SP2 is set to the minimum set The frequency increases corresponding to an increase in the pressure of the high temperature regenerator 2. At this time, the total lift of the first pump SP1 and the second pump SP2 is the sum of the total lift of the first pump SP1 and the lift corresponding to the frequency to the second pump SP2. When operating the refrigerator at the rated time, the heads of both pumps rise to the sum of the total heads of both pumps. Thus, the refrigerator shifts from the start-up operation to the steady operation.

  During partial load operation where the output of the refrigerator 1 is less than the rated output, the flow rate of the secondary refrigerant produced by the evaporator 6 fluctuates due to cooling load fluctuations, or the temperature of the cooling water supplied to the absorber 7 fluctuates. Therefore, the pressure in the high temperature regenerator 2 may fluctuate greatly. In such a case, by detecting the pressure change of the high temperature regenerator 2 accompanying the fluctuation of the combustion amount each time, controlling the frequency applied to the second pump SP2 as described above, and finely adjusting the head, Partial load operation can be stabilized.

  When the operation of the refrigerator is stopped, inverter control opposite to that at the start of operation of the first pump SP1 and the second pump SP2 is performed. That is, after the frequency to the second pump SP2 is gradually lowered and the frequency reaches the set minimum value, the frequency of the first pump SP1 is gradually lowered to connect other components such as a high-temperature regenerator and them. A dilution operation is performed in which the solution in the pipe is replaced with a dilute solution.

  Control during cooling operation of the refrigerator will be described with reference to FIG. The cooling operation (step 1) is started by combustion of fuel supplied to a burner installed in the high temperature regenerator 2 (step 2). At the beginning of operation, fuel is supplied at a low amount (step 4), and at this time, the first pump SP1 is operated at the set minimum frequency by the control device 16 (step 5). Until the temperature of the high-temperature regenerator 2 increases and reaches the set temperature (step 3), the fuel supply amount is supplied in proportion to the increasing temperature (step 6). When the set temperature is exceeded, the frequency applied from the control device 16 to the first pump SP1 is controlled based on the pressure in the high temperature regenerator 2, and increases as the pressure increases (step 7). When the pressure in the high temperature regenerator 2 reaches the set pressure (step 8), the second pump SP2 is started at the set minimum frequency by the control device (step 9). Thereafter, both the first and second pumps operate. When the frequency applied to the first pump SP1 reaches the set maximum frequency as the pressure in the high temperature regenerator 2 increases (step 10), the frequency applied to the second pump SP2 starts to increase (step 11). When the refrigerator has a rated output, the pressure in the high temperature regenerator 2 becomes the maximum value, and the frequency of the second pump SP2 becomes the set maximum frequency. The first and second pumps are driven at the set maximum frequency at the rated output of the refrigerator, and the total head of both pumps corresponds to the pressure in the high-temperature regenerator 2.

  Hereinafter, the heating operation of the refrigerator 1 will be described with reference to FIG. The refrigerator 1 has a pipe 42 for supplying the high-temperature refrigerant vapor generated in the high-temperature regenerator 2 to the evaporator 6, a heating switching valve 23 provided in the pipe 42, and an intermediate concentrated solution in the high-temperature regenerator 2 as an absorber. 7 and a heating switching valve 24 provided in the pipe 43. For the heating operation, the control device 14 first opens the heating switching valves 23 and 24. The high-temperature refrigerant vapor in the high-temperature regenerator 2 is supplied to the evaporator 6 from the high-temperature regenerator 2 through the pipe 42 through the heating switching valve 23, and the secondary refrigerant flowing through the heat transfer pipe 21 in the evaporator 6 is supplied. Heats to become a refrigerant liquid. On the other hand, the intermediate concentrated solution in the high temperature regenerator 2 flows into the intermediate temperature regenerator 3 through the pipe 30 through the high temperature solution heat exchanger 12, and then passes from the intermediate temperature regenerator 3 through the pipe 31 through the intermediate temperature heat exchanger 11. Further, it passes through the heating switching valve 24 through the pipe 43 branched from the pipe 31 and is sent to the absorber 7. The intermediate concentrated solution flowing into the absorber 7 is mixed with the refrigerant liquid flowing in from the evaporator 6 to become a diluted solution. The dilute solution is accumulated in the absorber 7 that communicates with the evaporator, and from there the low temperature solution heat exchanger 10, the exhaust gas heat exchanger 13, the intermediate temperature heat exchanger 11, and the high temperature solution heat exchanger through the return pipe 35 by the first pump SP1. 12 is returned to the high temperature regenerator 2 in order. The dilute solution is heated by the exhaust gas heat exchanger 13, the intermediate temperature heat exchanger 11, and the high temperature solution heat exchanger 12 on the way back. The secondary refrigerant heated by the high-temperature refrigerant vapor in the evaporator 6 is circulated between the evaporator 6 and the air conditioner for use in heating. When the refrigerator is operated for heating as described above, since the pressure in the high-temperature regenerator 2 is lower than that in the cooling operation, only one of the first pumps SP1 is operated by inverter control.

It is a block diagram of one Embodiment of the triple effect absorption refrigerator which applies this invention. It is a diagram which shows the HQ characteristic of the low head type pump used with the triple effect absorption refrigerator of embodiment compared with the conventional high head type pump. It is a diagram which shows the frequency characteristic of the low head type pump used with the triple effect absorption refrigerator of embodiment compared with the conventional high head type pump. It is a control diagram of the low head pump of 2 units | sets connected in series used with the triple effect absorption refrigerating machine of embodiment. It is a control flowchart of the low head pump of 2 units | sets connected in series used with the triple effect absorption refrigerating machine of embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Triple effect absorption refrigerator 2 High temperature regenerator 3 Medium temperature regenerator 4 Low temperature regenerator 5 Condenser 6 Evaporator 7 Absorber 10 Low temperature solution heat exchanger 11 Medium temperature solution heat exchanger 12 High temperature solution heat exchanger 13 Exhaust gas heat exchange 14 Cooling drain heat exchanger 15 Pressure detector 16 Control device 18 Heat transfer tube (medium temperature regenerator)
19 Heat transfer tube (low temperature regenerator)
20 Heat transfer tube (condenser)
21 Heat transfer tube (evaporator)
22 Heat transfer tube (absorber)
23 Heating switching valve 24 Heating switching valve SP1 First pump (upstream side)
SP2 Second pump (downstream)

Claims (3)

Triple effect absorption refrigeration equipped with a high temperature regenerator, a medium temperature regenerator, a low temperature regenerator, a condenser, an evaporator, an absorber and a feeding means for returning a dilute solution from the absorber to the high temperature regenerator for cooling operation. And the feeding means comprises two pumps that are inverter-controlled based on the pressure in the high-temperature regenerator, connected in series, and the two pumps have a total sum of their heads. The first pump, which has a total head corresponding to the generated pressure in the high-temperature regenerator during the cooling rated capacity operation and is arranged upstream of the two pumps when the cooling operation is started, is activated. And when the head of the first pump reaches a predetermined value near the total head of the first pump, the spiral second pump disposed downstream of the first pump is operated. Triple effect absorption refrigerator. A high temperature regenerator that heats a dilute solution to generate a high temperature refrigerant vapor and an intermediate concentrated solution, and a high temperature refrigerant vapor from the high temperature regenerator is heated by the high temperature refrigerant vapor from the high temperature regenerator to generate a high temperature refrigerant vapor. An intermediate temperature regenerator, a low temperature regenerator that heats the intermediate concentrated solution from the intermediate temperature regenerator by the high temperature refrigerant vapor from the intermediate temperature regenerator to generate a high temperature refrigerant vapor and uses the intermediate concentrated solution as a concentrated solution, and the low temperature A condenser that cools the high-temperature refrigerant vapor from the regenerator to form a refrigerant liquid; an evaporator that evaporates the refrigerant liquid from the condenser to form a low-temperature refrigerant vapor and cools the secondary refrigerant for cooling; An absorber that cools the concentrated solution from the low-temperature regenerator and absorbs the low-temperature refrigerant vapor from the evaporator into the concentrated solution to generate a diluted solution; and the diluted solution in the absorber is converted to the high-temperature regenerator A triple effect absorption refrigerator equipped with feeding means The feeding means is constituted by connecting two pumps that are inverter-controlled based on the pressure in the high-temperature regenerator in series, and the total of the total heads of the two pumps is the rating of the cooling system. Having a total head corresponding to the pressure generated in the high-temperature regenerator during capacity operation, and first operating the first pump disposed upstream of the two pumps when starting the cooling operation; When the first pump reaches a predetermined value close to the total head of the first pump, the spiral second pump disposed downstream of the first pump is operated, and the triple effect absorption type refrigerator. The triple-effect absorption refrigerator according to claim 1 or 2, wherein the first pump and the second pump are spiral pumps of the same model.

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