JPH0441272B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a water-lithium bromide absorption type water chiller/heater that can perform cooling and heating in one unit. The present invention relates to an absorption chiller/heater that is suitable for improving operability and is equipped with a mechanism for efficiently discharging liquid.

[Conventional technology]

Conventional hot water extraction methods for this type of water cooler/heater include: (a) introducing refrigerant vapor generated in a regenerator directly into an evaporator or absorber and exchanging heat with hot water flowing through the evaporator tube group; How to extract hot water from the evaporator group. Related devices of this type include, for example, Japanese Patent Application Laid-open No. 58-96963 and Utility Model Application No. 57-
No. 116076 is mentioned.

(b) A method in which the steam piping of the regenerator is branched and introduced into a separately installed hot water heat exchanger, and hot water is taken out from this hot water heat exchanger. An example of a related device of this type is JP-A-49-78251.

(c) During heating, the concentration of the solution in the regenerator is made extremely dilute to suppress the rise in boiling point, and the refrigerant vapor generated in the regenerator is sent directly to the condenser, or by condensation and re-evaporation in a low-temperature regenerator. A method in which hot water is extracted from the condenser tube group by introducing heat into the condenser tube group and exchanging heat with the hot water flowing through the condenser tube group. Related devices of this type include, for example, JP-A-57-
No. 73367 and JP-A-57-136063 are cited.

However, in method (a) above, since the solution is circulated in series from the high temperature regenerator to the low temperature regenerator, it is necessary to bypass the absorber during heating, and a switching valve is required for this purpose. This switching valve has the disadvantage that it requires a durable and expensive valve because hot solution and refrigerant vapor flow through it. In addition, method (b) requires a separate heat exchanger, which has the drawbacks of high cost and large space occupancy. Method (c) has a simple structure as an absorption type water chiller/heater, but it requires switching the load piping connection from the evaporator tube group to the condenser tube group during cooling and heating, and the operation during cooling is difficult. It has the disadvantage of complicating things.

In addition, during heating, it is necessary to operate a refrigerant spray pump to drain the refrigerant liquid from the evaporator to the absorber, and compared to methods (a) and (b), less consideration has been given to power saving.

An object of the present invention is to provide an absorption type water chiller/heater that extracts hot and cold water from an evaporator and uses the same solution circulation path during cooling as well as during heating, thereby simplifying the configuration, improving reliability, saving power, and reducing the size of the machine. It is about providing.

[Means to solve the problem]

In an absorption-type water chiller/heater that has multiple regenerators, condensers, evaporators, absorbers, heat exchangers, solution pumps, and refrigerant spray pumps connected via piping, the steam pipe connecting the condenser gas phase and the evaporator A bubble pump is provided at a position where the liquid refrigerant flows from the liquid refrigerant supply pipe from the bottom of the evaporator, and the liquid refrigerant of the evaporator pumped up by the refrigerant vapor generated in the regenerator is guided to the absorber. In addition to providing a pipe, a bypass pipe for bypassing refrigerant vapor is connected to the evaporation conduit that connects the bubble pump and the regenerator.

[Effect]

The refrigerant vapor generated in the regenerator is blown into the bottom of the bubble pump, while the liquid refrigerant in the evaporator flows into the bottom of the bubble pump via the refrigerant conduit and mixes with the vapor to form a two-phase gas-liquid phase. Since the gas-liquid two-phase head in the bubble pump is lower than the liquid refrigerant in the vessel and the liquid head to the bottom of the bubble pump, the liquid rises in the gas-liquid pump and is sent to the absorber. Since the pressure loss of the gas-liquid two-phase flow rising through the bubble pump becomes large when the amount of steam is large, by bypassing the flow through the bypass pipe, the pressure loss can be reduced and the bubble pump can be operated with high efficiency.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 5. In Fig. 1, 1 is a high temperature regenerator;
2 is a low temperature regenerator, 3 is a condenser, 4 is an evaporator, 5 is an absorber, 6 is a low temperature heat exchanger, 7 is a high temperature heat exchanger,
8 is a circulation pump, 9 is a refrigerant spray pump, 10 is a U-shaped seal that transfers the condensed liquid refrigerant from the condenser 3 to the evaporator 4,
11 is a U-shaped seal pipe that connects the condenser 3 and evaporator 4, and 12 is a spray liquid that connects the discharge port of the refrigerant pump 9 and the spray header 21 via a float valve. A conduit, 14 is a refrigerant tank, 15 is a branch pipe that branches from the spray liquid conduit 12 and communicates liquid refrigerant to the U-shaped seal pipe 11 via an inverted U-shaped seal, 16 is a refrigerant blow pipe, 2
4 is a bubble pump, 25 is a gas-liquid separator, 26 is an evaporation conduit, 27 is a refrigerant liquid conduit, 28 is a steam pipe, and 29 is a bypass pipe.

Next, the operation of this embodiment having the above configuration will be explained.

First, the case of cooling operation will be explained. The refrigerant vapor generated in the high-temperature regenerator 1 is guided into the low-temperature regenerator 2, condenses and liquefies by exchanging heat with the solution flowing down outside the tube, flows into the condenser 3 via the throttle 18, and cools the cooling water 3a. cooled down. The refrigerant vapor generated in the low-temperature regenerator 2 passes through the mist separator to the condenser 3.
It condenses and liquefies by exchanging heat with the cooling water 3a flowing through the heat transfer tube group, and flows into the evaporator 4 together with the refrigerant from the high-temperature regenerator 1 via the liquid refrigerant conduit 10 and the throttle 17. . In the evaporator 4, the liquid refrigerant is sprayed onto the heat transfer tube group by the refrigerant spray pump 9, evaporates by exchanging heat with the cooling water 4a flowing through the tube group, and removes the latent heat of vaporization from the cold water 4a, so that the refrigerating effect is achieved. can get. This evaporated refrigerant flows out into the absorber 5 and is absorbed by the absorbent solution flowing down the tube group cooled by the cooling water 5a in the absorber tube group. The solution in the absorber 5 is passed through the low temperature heat exchanger 6 by the circulation pump 8, divided and a part is supplied to the low temperature regenerator 2, the divided part is supplied to the low temperature regenerator 2, and the rest is The refrigerant is further supplied to the high-temperature regenerator 1 via a high-temperature heat exchanger 7 and a flow rate control mechanism (not shown), where refrigerant vapor is generated and concentrated.
The solution concentrated in the high temperature regenerator 1 is returned to the absorber 5 via the high temperature heat exchanger 7 and the low temperature heat exchanger 6 together with the concentrated solution in the low temperature regenerator 2. At this time, the liquid is sprayed from the spray header 22 onto the absorber heat transfer tube group by an ejector pump that uses part of the liquid discharged from the circulation pump 8 as a driving source.

In order to realize the cooling cycle with the above operation,
It is necessary to prevent refrigerant vapor from flowing from the condenser 3 to the evaporator 4 via the U-shaped seal pipe 11. In an absorption type water chiller/heater that uses water or an alcohol such as methanol as a refrigerant, the differential pressure between the condenser 3 and the evaporator 4 during cooling is small, and the differential pressure can be maintained sufficiently at the liquid column head of the refrigerant liquid. For example, under normal operating conditions when water is used as a refrigerant, the differential pressure is at most about 0.7 mAq, and the height of the entire absorption type water chiller/heater is approximately 1.5 m or more, so the gas phase of the condenser 3 and When the U-shaped sealed tube 11 communicating with the evaporator 4 is filled with refrigerant liquid, refrigerant vapor flows from the condenser 3 to the evaporator 4 via the U-shaped sealed tube 11 due to the differential pressure maintenance function of the liquid column head. This can prevent the influx. However, if the refrigerant liquid is simply filled, the refrigerant vapor from the condenser 3 will condense and liquefy on the refrigerant liquid surface forming the U seal, and the refrigerant liquid will be gradually heated and re-boiled on the evaporator 4 side of the U seal. Toshi,
The differential pressure maintenance function may be destroyed.

In the present invention, during cooling, the pressure inside the evaporator 4 is changed by operating the refrigerant spray pump 9, and the cooled refrigerant liquid having almost the same saturation pressure is continuously supplied from the branch pipe 15 to the U-shaped seal pipe 11. The difference maintenance function of the liquid column head can be maintained without causing reboiling, and the refrigerant vapor does not flow from the condenser 3 to the evaporator 4 via the U-shaped seal pipe 11 and the bubble pump 24, making it possible to realize a cooling cycle. .

Furthermore, if the connection point between the branch pipe 15 and the U-shaped seal tube is connected from the bottom of the U-shaped seal tube 11 to the evaporator 4 side, the refrigerant liquid from the bottom of the U-shaped seal tube 11 to the condenser 3 side will hardly move. . In this case, the surface concentration of the refrigerant liquid on the side of the condenser 3 is approximately at the condensation temperature, and the concentration at the bottom is approximately at the evaporation temperature, so that so-called temperature stratification hardly causes condensation and liquefaction. This has the effect of suppressing performance degradation.

In addition, the U-shaped seal pipe 11 and the steam conduit 26 are
By configuring the liquid path with a double pipe configuration, it can be made compact. However, if the refrigerant liquid splashes on the side of the U-shaped seal tube 11 that connects to the condenser 3, it will condense in the tube and transfer heat to the evaporator, causing a decrease in refrigerating capacity. Care must be taken in this regard when incorporating these devices within the evaporator shell. For example, by forming the side of the gas-liquid separator 25 that opens into the evaporator 4 or the absorber 5 into a louver shape from which the liquid is discharged, it is possible to prevent the refrigerant liquid or the absorption liquid from entering.

Next, the case of heating operation will be explained. In this case, the operation of the refrigerant spray pump 9 is stopped. Then, the liquid seal of the U-shaped seal tube 11 is broken, and some of the refrigerant vapor flows out from the gas vent hole b into the evaporator 4, but the rest passes through the evaporator tube 26, and most of the refrigerant vapor flows into the bypass tube. A part of the refrigerant vapor flows into the bubble pump 24 and mixes with the refrigerant in the refrigerant tank 14 via the refrigerant conduit 27, forming a two-phase flow and flowing into the bubble pump tube 24.
The refrigerant vapor flows out into the evaporator 4 and the liquid refrigerant flows out into the absorber 5 via the blow pipe 16.

The liquid refrigerant sent to the absorber 5 is mixed with the solution.
Dilute the cycle solution. Therefore, even if the evaporation pressure in the low-temperature regenerator 2 increases during heating, the boiling point can be kept below 100°C, and the pressure in the high-temperature regenerator 1 will not exceed atmospheric pressure.

The refrigerant vapor generated in the low-temperature regenerator 2 passes through the U-shaped seal pipe 11 and the vapor conduit 26, and most of it flows into the evaporator 4 via the bypass pipe 29, and the remaining refrigerant vapor also flows into the bubble pump 24, gas-liquid separator 25,
It flows out to the evaporator 4 via the steam conduit 28, exchanges heat with the hot water 4a flowing through the evaporator tube group, condenses, and flows into the refrigerant tank 14. At this time, the latent heat of condensation of the refrigerant vapor provides a heating effect.

The refrigerant liquefied in the evaporator 4 is discharged to the absorber 5 by the bubble pump 24.

Further, the solution is circulated in the same manner as during cooling operation.
Therefore, there is no need to provide any special flow path.

In addition, in order to prevent the solution circulation pump 8 from idling, a liquid level detector 40 is provided at the bottom of the absorber 5, and when the amount of liquid remaining at the bottom of the absorber 5 becomes extremely small, the circulation pump 8 and the refrigerant pump 9 are activated. A safety device is provided to stop the burner 30 and cooling water pump. When the external liquid level detector 40 operates, it is considered that crystallization occurs in the solution return channel from the regenerator, and in that case, the bubble pump 24 operates and automatically removes the solution. Dilute. Even if the liquid level detector 40 is restored, unless the refrigerant pump 9 is operated for a while using a timer or the like, the crystallization operation will be performed during that time.

Since the automatic crystallization operation is performed as described above, the reliability of the water chiller/heater is high and the operability is good.

The characteristics of the bubble pump 24 can be evaluated based on the amount of pumped refrigerant G, the amount of vapor of the driving refrigerant D, the tube length L of the bubble pump, and the suction head Hs. Hs constant, D
As D increases, G increases, but there is a certain limit, and increasing D beyond this point gradually decreases. Furthermore, when Hs is increased while Q is constant, G increases.

Fig. 2 shows the liquid pumping characteristics of a bubble pump that illustrates this. When Hs/L is large, that is, when the refrigerant liquid level in the evaporator is high, G is large, and the refrigerant liquid can be quickly discharged from the evaporator 4 to the absorber 5 in a short time. Further, even if the refrigerant vapor amount D increases, G will not increase beyond a certain limit. However, in the container liquid separator 25, when the refrigerant vapor amount D increases, the refrigerant vapor flow rate increases, the separation performance decreases, and the refrigerant liquid returns to the evaporator 4 again. Therefore, the amount of liquid that must be pumped by the bubble pump 24 increases, and as a result, Hs becomes higher and balanced. According to the experimental results, the inner diameter is 28mm and the length L is 0.6m.
Approximately 150 kg/h of refrigerant liquid is pumped using the bubble pump 24.
Kg/h of refrigerant vapor from the condenser can be discharged from the steamer to the absorber, and Hs at that time is at most 140
mm. At this time, approximately 70 kg/h of refrigerant vapor is bypassed. However, when the entire amount of refrigerant vapor was supplied to the bubble pump 24, Hs exceeded 280 mm, making it difficult to configure the heating cycle. In order to achieve such an appropriate design, a steam bypass pipe 29 for the bubble pump 24 is required. In addition, the bypass pipe 29
By connecting the liquid refrigerant of the evaporator 4 and the liquid refrigerant of the evaporator 4 through a thin conduit 39, the design of the refrigerant vapor distribution between the bubble pump 24 and the bypass pipe 29 becomes very easy. This is because the flow resistance pressure drop of the bypass pipe 29 is controlled by the amount of liquid refrigerant supplied through the thin conduit 39, so when Hs is high, a large amount of refrigerant vapor is supplied to the bubble pump 24, and when Hs is low, This is because the refrigerant liquid is no longer supplied from the thin conduit 39 and the refrigerant vapor flows in a single phase through the bypass pipe 29, so that a self-control mechanism can be constructed in which the amount of bypass is further increased.

Furthermore, since Hs can be made significantly smaller than in a rotary pump which has a cavitation limit, it can be lowered to the position of the refrigerant tank 14. Further, since the refrigerant tank 14 can be provided separately for the heating cycle and placed below the evaporator shell, there is an advantage that the space factor is improved and the water cooler/heater can be made more compact.

Furthermore, if the low-temperature regenerator 2 is a scattering type heat exchanger, the amount of accumulated liquid is small, so not only can the amount of solution be reduced, but also the amount of refrigerant that must be stored in the refrigerant tank 14 can be reduced, so the overall size can be reduced. There is an effect.

With the above configuration, this embodiment has the following effects.

1. Since the cold water and hot water outlets are common in the evaporator pipe group, there is no need to switch the piping connections between the load and the water cooler/heater, and operability is good.

2. The refrigerant pump can be stopped during heating, so power can be saved. On the other hand, during cooling, the refrigerant spray pump 9 can powerfully spray the refrigerant liquid onto the heat transfer tube group, and since the heat transfer coefficient is proportional to the 1/2 to 1/3 power of the amount of spraying, the heat transfer area of the evaporator can be saved.

3. Since the heating/cooling switching valve does not get stuck during the cycle, reliability is improved and costs can be reduced.

4. The solution circulation system is the same as that for cooling and heating, and there are no parts blocked by valves, so there is no solution stagnation, the corrosive environment is gentle, and there is no need to worry about local corrosion deterioration.

5. Heating operation constitutes a cycle with extremely low concentration, making it difficult to crystallize.

6 The amount of refrigerant vapor supplied to the bubble pump can be reduced, and the amount of currency refrigerant vapor in the vessel liquid separator is reduced, so the vessel liquid separation performance can be improved, allowing a more compact vessel liquid separator and the size of the bubble pump to be reduced. It can also be made smaller, reducing costs.

FIG. 3 is an explanatory diagram showing another embodiment of the present invention, in which a bubble pump 24 and a steam bypass pipe 29 are shown.
A thin conduit 39 communicating with the bypass pipe 27 and the gas phase part of the high temperature regenerator 1 are connected to the steam conduit 26 and the valve 40.
Connect via A.

When the valve 40A is opened during heating, the refrigerant in the refrigerant tank 14 is discharged to the absorber 5, but the refrigerant vapor generated in the high temperature regenerator 1 passes through the low temperature regenerator 2 and is mixed with the solution with a slight amount of heat. By being exchanged and cooled, the superheated state becomes saturated steam, and hot water is guided from the bypass pipe 29, the bubble pump 24, the bubble separator 25, and the steam conduit 28 to the evaporator 4 and passed through the pipe. This embodiment differs from the previous embodiment in that it is heated and that the U-shaped seal tube 11 is not provided. There is an effect that the structure can be made more compact due to the absence of the U-shaped seal tube 11.

In this embodiment, since the refrigerant vapor generated in the high temperature regenerator 1 is guided to the evaporator 4, the pressure loss in the steam system is increased, so the steam conduit 26 and the valve 10A are
This has the effect of reducing the size of. In addition, in order to guide the refrigerant vapor that has passed through the low-temperature regenerator 2 to the valve 40A, superheated steam generated in the high-temperature regenerator 1 (130℃~
The temperature is 100°C or less, which is less corrosive than when the refrigerant is passed through (150°C) or when a mixture of refrigerant vapor and solution is passed, making it a milder corrosive environment, which is advantageous in terms of valve durability.

Furthermore, if the valve body of the valve 40A is operated by the pressure of the refrigerant liquid discharged from the refrigerant pump 9, for example, by providing a diaphragm bellows, etc., by driving it with a piston, or by other methods, the refrigerant pump 9 It can be closed only during operation, and cooling operation can be configured.

Of course, the same effect can be obtained by using a solenoid valve as the valve 40A.

FIG. 4 shows yet another embodiment of the invention. This embodiment differs in that the discharge of the bubble pump 24 is directly connected to the absorber 5 without providing a gas-liquid separator, and that the branch of the bypass pipe 29 is replaced by the steam conduit 26. Since there is no gas-liquid separator, it has the advantage of being able to be configured compactly. In addition, since the bypass pipe 29 is traded in, a U-shaped seal is formed at this branch part, and refrigerant vapor is supplied to the bubble pump pipe 24 earlier than steam is supplied to the bypass pipe 29, so for example, from cooling to heating. When switching to the cycle, first, the bubble pump 24 is operated to discharge the liquid refrigerant from the evaporator 4, which has the effect of quickly reducing the absorbent concentration of the solution in the cycle. Also, valve 40
By opening A slightly, the liquid refrigerant in the evaporator 4 can be discharged during the cycle, so for example, if the temperature of the high-temperature regenerator 1 becomes abnormally high, or if the refrigerant in the evaporator 4 becomes supercooled. , when the liquid level in the absorber 5 drops abnormally and the solution pump 8 idles,
If the valve 40A is opened in the event of an abnormality such as a power outage trip, a large amount of refrigerant vapor can be sent to the evaporator 4 to dilute the solution in the absorber 5 without making the solution concentration in the high temperature regenerator 1 abnormally high, thereby providing a safety device. You can get the effect as.

FIG. 5 shows yet another embodiment of the invention. A functional pump is not required by connecting the liquid refrigerant distribution device to the solution heating outlet of the low temperature regenerator via the ejector pump 41 and connecting the bottom of the evaporator to the ejector to recirculate the unevaporated liquid. Although techniques for facilitating maintenance and reducing costs are known, the ejector pump 4 for liquid refrigerant to be sent to the refrigerant liquid distribution device is known.
An example of a combination configuration of No. 1 and the present invention is shown. An ejector pump 41 is provided in place of the refrigerant pump 9. The driving liquid refrigerant for the ejector pump 41 is supplied from a branch pipe 42 that branches between the steam conduit 26 and the valve 40A. At this time, if the openings of the ejector pump 41 and branch pipe 42 are located above the steam supply section at the bottom of the bubble pump, liquid refrigerant will not rise into the spray duct 12 during heating, and it will act as a bypass pipe for refrigerant vapor. . This embodiment has the advantage of high reliability since there is no refrigerant pump.

〔Effect of the invention〕

As described above, according to the present invention, liquid refrigerant in the evaporator can be efficiently discharged to the absorber using a bubble pump provided with a bypass pipe, so cold and hot water can be taken out from the evaporator in common, and the bubble separator and bubble This has the effect of making the pump pipe smaller.

[Brief explanation of drawings]

Fig. 1 is a cycle flow diagram of one embodiment of the present invention, Fig. 2 is a pumping characteristic of a bubble pump, and Figs. 3, 4, and 5 are cycle flows of other embodiments of the present invention. It is a diagram. 1...High temperature regenerator, 2...Low temperature regenerator, 3...
Condenser, 4... Evaporator, 5... Absorber, 6... Low temperature heat exchanger, 7... High temperature heat exchanger, 8... Circulation pump, 9... Refrigerant spray pump, 10... Refrigerant liquid conduit, 11... U-shaped seal pipe, 12... Refrigerant spray conduit, 13... Float valve, 14... Refrigerant tank, 15... Branch pipe, 16... Refrigerant blow pipe, 1
7,18...Aperture, 19,20...Eliminator, 21,22,23...Spray header, 24...
...bubble pump, 25... gas-liquid separator, 26... vapor conduit, 27... refrigerant conduit, 28... vapor conduit,
29... Bypass pipe, 30... Burner, 31...
Once-through boiler, 32... Gas-liquid separator, 33... Bypass pipe, 34... Float box, 35... Float valve, 39... Thin conduit, 40... Bottom detector, 40A... Valve, 41... ejector pump.

Claims (1)

[Scope of Claims] 1. In an absorption type water chiller/heater in which a plurality of regenerators, condensers, evaporators, absorbers, heat exchangers, solution pumps, and refrigerant spray pumps are connected via piping, the condenser gas phase and the evaporator A bubble pump is provided in the middle of the steam pipe connecting the evaporator to the evaporator at a position where the liquid refrigerant flows in from the liquid refrigerant supply pipe from the bottom of the evaporator, and the evaporator is pumped with refrigerant vapor generated in the regenerator. 1. An absorption chiller/heater, characterized in that a pipe is provided for guiding the liquid refrigerant to the absorber, and a bypass pipe for bypassing the refrigerant vapor is connected to the vapor conduit connecting the bubble pump and the regenerator. 2. Claims characterized in that a U-shaped seal pipe is provided in the steam conduit connecting the condenser, the bubble pump, and the bypass pipe, and a branch pipe branched from the refrigerant pump discharge side is connected to the U-shaped seal pipe. The absorption type water chiller/heater according to item 1. 3. The absorption type according to claim 1, characterized in that a solenoid valve is provided in the evaporation pipe that connects the regenerator, the bypass pipe, and the bubble pump, and is closed when the cooling water pump is turned on. Hot and cold water machine. 4. A thin conduit connecting the bypass pipe and the evaporator is provided, and when the refrigerant liquid level in the evaporator is high, the refrigerant liquid is supplied to the bypass pipe via the thin conduit,
2. The absorption type water chiller/heater according to claim 1, wherein when the liquid level of the evaporator is low, the opening of the thin conduit in the evaporator is located in the gas phase region. 5. In an absorption type water chiller/heater that is constructed by connecting multiple regenerators, condensers, evaporators, absorbers, heat exchangers, solution pumps, and refrigerant spray pumps, the refrigerant generated by the high-temperature regenerator passes through the low-temperature regenerator heating section. A pipe is provided that branches the vapor and communicates with the evaporator via a valve, and a bubble pump is provided in the middle of this pipe at a position where the liquid refrigerant flows from the liquid refrigerant supply pipe from the bottom of the evaporator.
A bypass pipe is provided to guide the liquid refrigerant of the evaporator pumped up by the refrigerant vapor generated in the regenerator to the absorber, and to bypass the refrigerant vapor to a vapor conduit connecting the bubble pump and the regenerator. An absorption type water chiller/heater that is characterized by being connected to. 6. The absorption type according to claim 5, characterized in that a solenoid valve is provided in the steam pipe communicating with the regenerator, the bypass pipe, and the bubble pump, and is closed when the cooling water pump is turned on. Hot and cold water machine. 7. A thin conduit is provided to connect the bypass pipe and the evaporator, and when the refrigerant liquid level in the evaporator is high, the refrigerant liquid is supplied to the bypass pipe via the thin conduit,
6. The absorption type water chiller/heater according to claim 5, wherein when the liquid level of the evaporator is low, the opening of the thin conduit in the evaporator is located in the gas phase region.