JPS6115342B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an absorption refrigerator that configures a refrigeration cycle using water or alcohol as a refrigerant and a salt solution such as a lithium bromide solution as an absorption solution.

Conventionally, this type of refrigerator has an absorber, a generator, a condenser, an evaporator, a solution heat exchanger, a solution pump, a refrigerant pump, and these devices connected through a solution line and a refrigerant line. A refrigeration cycle is formed by exchanging heat with the outside.

In such an absorption refrigerator, the concentration of the solution becomes diluted due to changes in conditions such as a decrease in load or a decrease in cooling water temperature, which causes the refrigerant level in the evaporator to drop, and in some cases, cavitation of the refrigerant pump. This can lead to accidents such as operation without lubrication. In order to prevent this accident, a solution introduction system is installed to guide the solution in the absorber into the evaporator, and when the refrigerant liquid level in the evaporator becomes lower than a predetermined height, the solution is introduced into the evaporator via the solution introduction system. This causes the mixture of solution and solvent to rise in the liquid level, thereby preventing cavitation or the like from occurring.

In this way, in absorption refrigerators that are operated with an absorption solution mixed into the refrigerant in the evaporator, the concentration of absorbent in the refrigerant liquid in the evaporator remains constant for most of the operating period of the refrigerator. This is a rare condition. Concentrations become high when the outside temperature is low, when the cooling water temperature is low, when the load is low, and for a relatively short period of time. In particular, the concentration becomes high only during a very short period of time immediately after the absorption solution is mixed in when the cooling water is at low temperature or when the load is low.

On the other hand, when the absorbent is a LiBr solution and the refrigerant is water, the specific gravity of the mixed liquid in this evaporator is usually 1.0 to 1.1.
The maximum value is about 1.6. However,
As for the power of the refrigerant pump, the output of the pump motor was selected in consideration of the maximum specific gravity of the refrigerant (the highest specific gravity occurs when the absorbent concentration is at its highest concentration) even if the period is short. Therefore, the normal operating point is far away from the motor's rated output point, and the motor is used at a point where its efficiency is poor, resulting in large power consumption.Moreover, the motor's output is also large, which increases equipment costs. It was hot.

The present invention directly or indirectly detects the specific gravity of the refrigerant liquid in the evaporator, and when the specific gravity exceeds a predetermined value, the flow rate of the refrigerant liquid in the evaporator is controlled to be reduced. Except for the above drawbacks,
The purpose of the present invention is to provide an absorption chiller that allows the shaft power of the refrigerant pump to be selected to a value close to the power during normal operation, and that can be operated with high efficiency and that does not require excessive motor output. It is something to do.

The present invention provides absorbers, generators, condensers, evaporators,
In an absorption refrigerator which forms a refrigeration cycle by including a solution heat exchanger, a solution pump, a refrigerant pump, and a solution path and a refrigerant path connected thereto, the solution in the absorber, the generator, or the solution path is evaporated. a specific gravity detection mechanism for detecting a refrigerant liquid specific gravity variation element related to a specific gravity variation of the refrigerant liquid in the evaporator; The absorption refrigerator is characterized in that it is equipped with a flow rate control mechanism that controls the flow rate of refrigerant liquid sprayed into the cold water pipes.

The present invention will be explained with reference to the drawings in accordance with embodiments. As shown in FIG. 1, an absorber A, a generator G, a condenser C, an evaporator E, a solution heat exchanger X, a solution pump
PS, a refrigerant pump PM are provided, and pipes 1, 2, 3, 4, 5, a spray pipe 6, and an overflow pipe 7 are provided as a solution path, and pipes 8 and 7 are provided as a refrigerant path.
9, a spray pipe 10, and a pipe 11 connect the above-mentioned devices to form a refrigeration cycle.

12 is a heating tube, and 13 is a heat source heat amount control valve.
The cooling water system includes a cooling water pump 14, piping 1
5, a cooling water pipe 16, a pipe 17, a cooling water pipe 18, and a pipe 19 are provided to cool the absorber A and the condenser C. 20 is a cold water pipe, pipe 2
1 and 22 lead cold water to the evaporator E.

41 is for guiding the solution in the absorber A into the evaporator E to prevent cavitation.
This is a solution introduction pipe that connects the outlet of the solution pump PS and the inlet of the refrigerant pump PM, and the introduction of the solution is operated by the control valve 42. The control valve 42 includes a detection mechanism that directly or indirectly detects the height of the refrigerant liquid level in the evaporator E (for example, a liquid level gauge 50 in the evaporator E, a thermometer for cooling water temperature, a cooling water outlet temperature, etc.). ) is operated via the control mechanism 51.

43 is a refrigerant liquid introduction pipe connecting the outlet of the refrigerant pump PM and the inlet of the solution pump PS in order to introduce the refrigerant liquid in the evaporator E into the solution line;
The control valve 44 controls the introduction of the refrigerant liquid. The refrigerant liquid introduction pipe 43 is provided to dilute the solution in order to prevent the risk of crystallization of the solution due to an increase in concentration, and the control valve 44 directly or indirectly detects the concentration of the solution. It is operated by a detection mechanism or a signal issued immediately before the device stops operating.

The piping 9 on the outlet side of the refrigerant pump PM is provided with an orifice 45 and a control valve 47 in a bypass 46 in parallel with the orifice 45. Evaporator E
A specific gravity detection mechanism 48 is provided in the refrigerant liquid, and when the specific gravity exceeds a set value, the control mechanism 4 is activated by the signal.
9 closes the control valve 47 to reduce the spray flow rate of the refrigerant liquid.

FIG. 2 shows an embodiment of the specific gravity detection mechanism 48. A reed switch 53 is provided at an appropriate height in a non-magnetic tube 52 extending through the bottom of the evaporator E. An annular float 54 is attached to the outside of the tube 52 so as to be movable up and down. A magnet 55 is provided on a part of the float 54. tube 5
2 is provided with stoppers 56 and 57 that determine the upper and lower limit positions of the float 54, and at the upper limit position, a magnet 55 activates the reed switch 53,
At the lower limit position, the magnet 55 is separated from the reed switch 53 and is not activated. The specific gravity of the material of the float 54 is chosen to be equal to the set specific gravity. For the float 54, a material having a uniform specific gravity equal to the set specific gravity may be selected as a whole, or materials having different specific gravity may be appropriately combined to form the set specific gravity as a whole.

During normal operation, the control valve 47 is fully opened, and the flow rate of the refrigerant liquid sprayed into the cold water pipe 20 is at its maximum value. In this case, since no solution has flowed into the evaporator E or there is only a very small amount remaining, the specific gravity of the refrigerant liquid is at the minimum or close to it (for example, 1.0 to 1.1) and the float 54 of the specific gravity detection mechanism 48
is at the lowest position, the reed switch 53 is not operated, the control valve 47 remains open, and the amount of refrigerant sprayed is at its maximum value.

If the load decreases or the cooling water temperature decreases, the amount of refrigerant absorbed into the solution increases, and if the refrigerant liquid level in the evaporator E falls below the set value, this is detected by the liquid level gauge 50. is detected, the control valve 42 is opened by the control mechanism 51, a part of the solution is introduced into the pipe 8 through the solution introduction pipe 41, enters the lower part of the evaporator E, raises the refrigerant liquid level, and the refrigerant pump PM
It is sent into the piping 9 by.

When the solution is mixed into the refrigerant liquid, the specific gravity increases and can reach a maximum of about 1.6. When the specific gravity exceeds a preset specific gravity setting value (for example, 1.2), the float 54 rises to the top and reaches the highest position, and the reed switch 53 is activated.
is activated to close the control valve 47, and the refrigerant liquid is throttled by the orifice 45 to a low flow rate, and the required power of the pump also falls within the set value. On the other hand, as the specific gravity of the refrigerant increases to the set value, or as the amount of refrigerant spray decreases, the heat transfer of the evaporator E decreases, and the solution cycle moves to the rich side, so the refrigerant liquid level does not drop excessively, and therefore The refrigerant concentration will not become any higher. The solution cycle becomes highly concentrated due to an increase in the chilled water load or a rise in the temperature of the coolant, and the refrigerant liquid level rises and the refrigerant specific gravity decreases, so that the control valve 47 opens again.

Since this embodiment is configured and operates as described above,
When the specific gravity of the refrigerant liquid in the evaporator E temporarily increases, the flow rate of the refrigerant pump PM is reduced to prevent the required power from becoming excessive, and a motor with an output close to the power during normal operation is used. The refrigerant pump PM can be selected to increase efficiency during normal operation and reduce power consumption, and the output of the motor and refrigerant pump PM can be selected to be small, reducing the number of equipment.

Since the specific gravity of the refrigerant liquid becomes large when the load is relatively small with respect to the refrigerating capacity, there is no problem in reducing the amount of spraying.

In FIG. 3, the control valve 47 is provided directly in the pipe 9. In FIG. In this case, the control valve 47 is a stepwise or continuous flow rate control valve, and the specific gravity detection mechanism 48 is a mechanism that detects specific gravity stepwise or continuously.

An example of a stepwise specific gravity detection mechanism is shown in FIG. tube 5
2 has three reed switches 58, 59,
60 is provided, and stoppers 56, 57,
Floats 63, 64, 65 are mounted between 61, 62 so as to be movable up and down. Float 63, 64,
The specific gravity S ₁ , S ₂ , and S ₃ of 65 are different, for example, S ₁
<S ₂ <S ₃ . 66, 67, and 68 are magnets.

When the specific gravity S _R of the refrigerant liquid becomes S _R <S ₁ , all the floats 63, 64, 65 are lowered and the reed switches 58, 59, 60 do not operate, but S ₁ <
When S _R <S ₂ , only the float 54 floats up, actuating the reed switch 58 and emitting a signal.
In the same way, the states S ₂ <S _R <S ₃ and S ₃ <S _R are detected.

Refrigerant pump PM is used for flow control without using a valve.
This may also be done by controlling the rotational speed of the shaft. The rotation speed control includes control of the rotation speed of the motor, control of the gear ratio in the intermediate power transmission mechanism, and the like.

Even when a valve is used, rotation speed control of the refrigerant pump PM can be used in combination. Refrigerant pump PM when the specific gravity of the refrigerant liquid is high, whether used in combination or alone.
may be controlled to stop.

To detect the refrigerant liquid specific gravity variation element that is involved in the specific gravity variation of the refrigerant liquid, the solution concentration may be detected directly or indirectly. Further, even if the refrigerant liquid level is constant, the discharge pressure or differential pressure of the refrigerant pump PM changes depending on the specific gravity, so this discharge pressure or differential pressure may be detected.

The present invention provides absorbers, generators, condensers, evaporators,
In an absorption refrigerator that forms a refrigeration cycle by including a solution heat exchanger, a solution pump, a refrigerant pump, and a solution path and a refrigerant path that connect these, the solution in the absorber, generator, or solution path is evaporated. a specific gravity detection mechanism for detecting a refrigerant liquid specific gravity variation element related to a specific gravity variation of the refrigerant liquid in the evaporator; Equipped with a flow rate control mechanism that controls the flow rate of refrigerant liquid sprayed into the cold water pipes, the output of the refrigerant pump can be appropriately selected to avoid excessive output, improving efficiency during normal operation and reducing power consumption. It is possible to provide an absorption chiller that can reduce consumption and reduce equipment costs by selecting a small motor output, and has an extremely large effect in terms of practical and energy saving. It is.

[Brief explanation of the drawing]

The drawings relate to embodiments of the present invention; FIG. 1 is a flow diagram, FIG. 2 is an explanatory diagram of an embodiment of the specific gravity detection mechanism, FIG. 3 is a flow diagram of another embodiment near the evaporator, and FIG. The figure is an explanatory diagram of another embodiment of the specific gravity detection mechanism. A...absorber, G...generator, C...condenser,
E... Evaporator, X... Solution heat exchanger, PS... Solution pump, PM... Refrigerant pump, 1, 2, 3,
4, 5... Piping, 6... Spray pipe, 7... Overflow pipe, 8, 9... Piping, 10... Spray pipe, 11... Piping, 12... Heating pipe, 13...
Heat source heat amount control valve, 14...Cooling water pump, 15...
...Piping, 16...Cooling water pipe, 17...Piping, 18
...Cooling water pipe, 19...Piping, 20...Cold water pipe,
21, 22...Piping, 41...Solution introduction pipe, 42
... Control valve, 43 ... Refrigerant liquid introduction pipe, 44 ... Control valve, 45 ... Orifice, 46 ... Bypass,
47... Control valve, 48... Specific gravity detection mechanism, 49...
...Control mechanism, 50...Liquid level gauge, 51...Control mechanism, 52...Pipe, 53...Reed switch, 54
...Float, 55...Magnet, 56,57...Stopper, 58,59,60...Reed switch,
61, 62... Stoppa, 63, 64, 65...
Float, 66, 67, 68... magnet.

Claims (1)

[Claims] 1. An absorption refrigerating machine comprising an absorber, a generator, a condenser, an evaporator, a solution heat exchanger, a solution pump, a refrigerant pump, and a solution path and a refrigerant path connected thereto to form a refrigeration cycle. A specific gravity system comprising: a solution introduction system for guiding a solution in the absorber, the generator, or the solution path to the evaporator, and detecting a refrigerant liquid specific gravity variation element related to specific gravity variation of the refrigerant liquid in the evaporator; An absorption refrigerator comprising: a detection mechanism; and a flow rate control mechanism that controls the flow rate of refrigerant liquid sprayed into cold water pipes in the evaporator based on a signal from the specific gravity detection mechanism. 2. The absorption refrigerator according to claim 1, wherein the refrigerant liquid specific gravity variation element is detected by detecting the specific gravity of the refrigerant liquid in the evaporator. 3. The specific gravity detection mechanism is a detection mechanism that holds a float that has a predetermined specific gravity and incorporates a magnet so as to be able to rise and fall, and is equipped with a reed switch that detects movement of the float. absorption refrigerator. 4. The absorption refrigerator according to claim 1, wherein the flow rate control mechanism is a flow rate control valve provided in the discharge side flow path of the refrigerant pump. 5. The absorption refrigerator according to claim 1, wherein the flow rate control mechanism is a mechanism for controlling the rotation speed of the refrigerant pump.