JPS6013017Y2 - Absorption chiller with heating/cooling switching and automatic concentration adjustment mechanism - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an absorption refrigerator equipped with a mechanism that switches between heating and cooling modes and automatically adjusts the concentration of a circulating solution.

Generally, when an absorption refrigerator is used for cooling and heating, it requires a switching mechanism for heating and cooling, and a mechanism that automatically changes the concentration of the circulating solution to prevent it from crystallizing under fluctuating conditions during cooling operation. Since these mechanisms are provided separately, the structure becomes complicated and the manufacturing cost increases.

The present invention aims to solve these problems by equipping the absorption refrigerator with a mechanism that switches between heating and cooling modes and automatically adjusts the concentration of the circulating solution, thereby enhancing its functionality and simplifying its structure. The purpose is to

・For this reason, the absorption refrigerator having the cooling/heating switching and concentration automatic adjustment mechanism of the present invention is composed of a regenerator, 9 separators, @ condenser, evaporator, absorber, and heat exchanger. A thick flow path led from the bottom includes an overflow part and a reservoir part for maintaining a constant liquid level height, and an opening of a first conduit for discharging the overflowing liquid from this to the evaporator. A refrigerant bleeder is connected to a constant liquid level device having a constant liquid level device, and a refrigerant bleeder is connected to the reservoir portion of the constant liquid level device through a second conduit, and a thick flow path is connected to the evaporator from the upper side of the refrigerant reservoir. The first conduit is formed as a thin U$-shaped conduit, and the second conduit is connected to the second conduit.
The pipe is formed as a thick U-shaped conduit.

In the above-mentioned absorption refrigerator, a constant liquid level device with an overflow section and a refrigerant section is provided, and the reservoir section and the refrigerant reservoir are connected by a thick U-shaped conduit.
Therefore, the liquid level in the U-shaped conduit is not exceeded, and a constant liquid level is maintained in the constant liquid level device, making it possible to reliably adjust the concentration of the solution according to the operating conditions. Since the refrigerant can be retained even when the operation is stopped, it not only contributes to energy saving but also has the advantage that the operation can be restarted easily and smoothly.

In particular, a thick flow path is connected to the evaporator from the upper side of the refrigerant reservoir, so when the liquid accumulated in the refrigerant reservoir reaches the flow path, the refrigerant bypasses the evaporator, thereby preventing overconcentration of the circulating solution. There is no possibility of operation failure due to crystal precipitation.

Furthermore, the refrigerant is circulated during heating switching by the action of the thick flow path connected from the bottom of the condenser to the constant liquid level device, the aforementioned thick U-shaped conduit, and the thick flow path from the upper side of the refrigerant reservoir to the evaporator. By returning it to a solution, the concentration during heating can be diluted, and at the same time it can form a path for refrigerant vapor during heating, resulting in the following effects.

(1) Automatic switching function for heating and cooling can be obtained.

(2) The automatic adjustment function of the circulating solution concentration is performed as follows during cooling and heating.

It operates as follows in response to changes in cooling water temperature from the cooling rated point.

a When the cooling water temperature rises, the concentration of the circulating solution is automatically increased to prevent a drop in cooling capacity, but the solution has the property of precipitating crystals depending on the concentration and temperature, so it prevents operation failure due to crystallization. Therefore, if the refrigerant liquid level rises excessively, overflow occurs due to the above-mentioned thick flow path connected to the side surface of the refrigerant reservoir 19 to prevent the refrigerant concentration from becoming more concentrated than the maximum allowable concentration.

Further, even when the operation is stopped, the refrigerant can be retained in the thick U-shaped conduit described above.

b. When the cooling water temperature becomes low, the concentration of the circulating solution is automatically lowered to prevent operation failure due to freezing of the refrigerant in the evaporator due to an excessive increase in absorption capacity.

By significantly lowering the concentration of the circulating solution during heating, efficiency is improved, and operation failure due to crystallization of the solution due to a drop in outside temperature is prevented.

In addition, since the conduit 17 that guides the liquid overflowing from the constant liquid level device to the evaporator 4 is formed as a thin U-shaped conduit, there is a sufficient pressure difference between the space on the condenser 3 side and the evaporator 4. is maintained, and the liquid in the evaporator 4 is efficiently evaporated.

Next, an example of the present invention will be explained with reference to the drawings.
Fig. 11 shows the system before installing the heating/cooling switching/concentration automatic adjustment mechanism - FJ tube, regenerator 1, separator 2. Condenser 3. Evaporator 4. The absorber 5° and the heat exchanger 6 or 98 are connected by piping and filled with the required amount of solution.

Cooling pipes 7.8 in the absorber 5 and condenser 3 are connected to a cooling tower 9 via a cooling water circulation pump 10, and a cold and hot water pipe 11 in the evaporator 4 circulates cold and hot water to an air conditioner 12 such as a fan coil. They are connected via a pump 13.

The heater 14 of the regenerator 1 may be an external combustion type burner using gas, oil, etc. or an internal heating type steam pipe, hot water pipe, etc., but a burner is shown here.

Aqueous ammonia (refrigerant: ammonia, absorbent: water), lithium bromide aqueous solution (refrigerant: water, absorbent: lithium bromide), etc. have been put into practical use as solutions used in this absorption refrigerator, but in this paper, The device of the invention has a regenerator 1. The pressure difference between the high pressure side pressure of the condenser 3 and the low pressure side pressure of the absorber 5 and evaporator 4 (hereinafter referred to as
It's simply called pressure difference.

) is relatively small, and the case where a lithium bromide aqueous solution is used will be explained below.

In the case of the cooling action of an absorption refrigerator, the regenerator 1 is used in the heater 14.
When the solution inside is heated to boiling, along with water vapor bubbles,
The solution rises and is separated into water vapor and concentrated solution in the separator 2. The water vapor then condenses into water in the condenser 3 (evaporator 4 removes heat from the hot and cold water pipe 11 and evaporates. do.

At this time, cold water is created in the hot and cold water pipe 11.

On the other hand, the concentrated solution descends from the separator 2, passes through the heat exchanger 6, enters the absorber 5, absorbs the water vapor exiting the evaporator 4, accelerates evaporation in the evaporator 4, and becomes diluted by itself. It becomes a solution and returns to the regenerator 1 via the heat exchanger 6, where the same cycle is repeated.

In the case of heating, cooling water is not passed through the cooling pipes 7 and 1, and the water vapor leaving the separator 2 does not condense in the condenser 3, but instead enters the evaporator 4 and releases the heat of condensation in the hot and cold water pipe 11, where it is condensed. do.

At this time, hot water is created in the cold/hot water pipe 11.

The rest is the same as □ Cooling action, so the explanation will be omitted.

This type of refrigerator evaporates the refrigerant at a low temperature, so the inside of the refrigerator is kept at a high vacuum, and the regenerator 1. The pressure of the condenser 3 is 60-70 Hgabs, the pressure of the evaporator 4. The pressure in the absorber 5 is about 6 to 7 WIHgabS.

-□ Fig. 2 shows the flow of incorporating the heating/cooling switching and automatic concentration adjustment mechanism of the present invention.

The heating/cooling switching and automatic concentration adjustment mechanism is provided in the above-mentioned absorption refrigerator by using a constant liquid level device 16 that is connected to the condenser 3 via the introduction pipe 15 and a U-shaped conduit that connects this to the evaporator 4. evaporator U seal 17, a refrigerant reservoir 19 connected to the constant liquid level device 16 via a refrigerant reservoir U seal 18 as a U-shaped conduit, and a connecting pipe connecting this refrigerant reservoir 1-9 to the evaporator 4. It consists of 20.

Since this cooling/heating switching/concentration automatic adjustment mechanism has two functions: automatic concentration adjustment and cooling/heating switching, the automatic concentration adjustment will be explained first.

In an absorption refrigerator that uses an aqueous lithium bromide solution as an absorbent, if the concentration of the solution is too low, the absorption capacity of the absorber 6 will decrease and the refrigeration capacity will decrease, and if the concentration is too high, the solution will crystallize. Refrigerant freezing may occur, making operation impossible. Therefore, the solution concentration must be constantly adjusted in response to conditions such as fluctuations in the amount of cooling water, fluctuations in the temperature of the cooling water, fluctuations in the amount of cold and hot water, fluctuations in the temperature of cold and hot water, and fluctuations in the refrigeration load. It is necessary to adjust it appropriately.

By utilizing the fact that the pressure difference between the high-pressure side pressure and the low-pressure side pressure, which is determined by the temperature of the cooling water entering the condenser 3, changes in response to the above fluctuation conditions, the refrigerant contained in the circulating solution is By automatically separating and storing the refrigerant in the refrigerant reservoir 19, when the pressure difference is small, the amount stored is reduced to dilute the concentration of the circulating solution, and when the pressure difference is large, the amount stored is increased to reduce the concentration of the circulating solution. At the same time, by setting the maximum allowable concentration and preventing the circulating solution concentration from becoming thicker than the maximum concentration even if the pressure difference becomes too large, the circulating solution concentration can be maintained at an appropriate level under all operating conditions. By doing so, it is possible to prevent the power of crystals.

FIG. 3 shows a detailed structure of an example of a heating/cooling switching/concentration automatic adjustment mechanism.

In FIG. 3, the refrigerant condensed in the condenser 3 is transferred to the inlet pipe 15.
The liquid is then introduced into the constant liquid level device 16.

The constant liquid level device 16 has an overflow part 16a and a reservoir part 16b, and the refrigerant from the condenser 3 flows into this reservoir part 1.
By pouring the liquid into the side 16b, the liquid level in the reservoir 16b remains constant even if the operating conditions change.

The overflowing refrigerant then enters the evaporator 4 through the evaporator U-seal 17 as a narrow U-shaped conduit.

In this way, the space on the condenser 3 side and the evaporator 4 are connected through a thin U-shaped conduit, so a sufficient pressure difference is maintained between the two, and evaporation in the evaporator 4 is performed efficiently. .

Further, the refrigerant in the reservoir 16b enters the refrigerant reservoir 19 through the refrigerant reservoir U seal 18, which is a thick U-shaped conduit, and accumulates in the refrigerant reservoir 19 to a height H corresponding to the pressure difference.

The height H corresponding to the pressure difference changes as the pressure difference changes, and as a result, the circulating solution concentration changes as the amount of refrigerant that accumulates changes.

A connecting pipe 20 leading from the upper side of the refrigerant reservoir 19 to the evaporator 4
is highest at the connection point between i and the refrigerant reservoir 19, as shown in FIG. 3, thereby determining the location of the overflow of the refrigerant reservoir 19 and determining the maximum concentration of the circulating solution.

As a specific example of this, FIG. 5 shows cycles M and N in the case of automatic concentration adjustment.

When the temperature of the cooling water increases, when the load is high, or when the amount of cooling water decreases, the pressure difference increases, and the above-mentioned height H increases and the concentration of the circulating solution increases.

In addition, when the salinity of the cooling water decreases, when the load is low, or when the amount of cooling water increases, the pressure difference becomes smaller, the above-mentioned height H becomes smaller, and the circulating solution concentration becomes thinner.
In this way, the appropriate concentration is always achieved.

In the above automatic concentration adjustment during cooling operation, the constant liquid level device 1.6 and the refrigerant reservoir 19 are connected via the refrigerant reservoir U seal 18, which is a thick U-shaped conduit, so that the concentration can be adjusted reliably. In addition, stable operation and energy-saving operation can be achieved.

That is, as mentioned above, since the pipe 18 connecting the constant liquid level device 16 and the refrigerant reservoir 19 is a thick U-shaped conduit,
In addition to the amount of refrigerant corresponding to the height H corresponding to the pressure difference between the condenser 3 and the evaporator 4, a constant amount of refrigerant can always be held in the U-shaped conduit.

For this reason, for example, □ Even if there is an urgent change in operating conditions such as a sudden increase in the pressure difference due to a sudden rise in the cooling water temperature, the refrigerant can be reliably held at a height H (commensurate with the distance where the pressure difference increases). This prevents the refrigerant from blowing into the evaporator 4, allowing stable operation, and also helps save energy by eliminating the generation of ineffective refrigerant (refrigerant that does not contribute to cooling). .

In addition, during cooling operation, depending on the state of the cooling load, the operation and stop may be repeated, and when it is stopped, there will be no pressure difference between the condenser and evaporator, so the refrigerant reservoir 19 will be closed until the difference in height H disappears.
The refrigerant moves from the side to the constant liquid level device 16 side, but the refrigerant reservoir U seals 1, 8. Since refrigerant can always be kept inside the constant liquid level device 16 and the refrigerant reservoir 19, it is possible to smoothly transition to steady operation at the time of restart, and the step of storing refrigerant ( During this time, it does not contribute to cooling.

), allowing efficient operation.

Next, to explain the effect of cooling/heating switching, the third
The evaporator U seal 17 and refrigerant reservoir U seal 18 shown in the figure are as follows:
The pressure difference is maintained by liquid sealing with refrigerant.

When the heating operation starts, the cooling water is not passed through the cooling pipes 7 and 8 as described above, so the pressure difference at the start of the heating operation is larger than the pressure difference during the cooling operation, and the evaporator U seal 17 and the refrigerant reservoir U The seal 18 no longer blocks the refrigerant, and the refrigerant is expelled to the evaporator 4, and the evaporator U seal 17 and the refrigerant reservoir U seal 18 form a vapor circuit.

When the liquid blockage is removed, the pressures in the condenser 3 and evaporator 4 become almost the same.

In addition, in order to return all the refrigerant in the refrigerant reservoir 19 to the circulating solution during heating, the inlet pipe 15. The refrigerant reservoir U seal 18 and the connecting pipe 20 are made thick enough to allow steam to pass through, and the evaporator U seal 17
As mentioned above, the tube is relatively thin so that the liquid in the evaporator 4 can be efficiently evaporated.

A specific example in which the refrigerant accumulated in the refrigerant reservoir 19 is actively expelled is shown in FIG.

That is, by communicating the refrigerant reservoir U seal 18 with the connecting pipe 20 and providing the refrigerant return pipe 21 and pressure equalization hole 22 in the communication portion, the steam flowing through the refrigerant reservoir U seal 18 and the connecting pipe 20 during heating can be The refrigerant coming from the refrigerant return pipe 21 is made into small droplets and transported to the evaporator 4' by the ejector effect, whereby all the refrigerant in the refrigerant reservoir 19 returns to the circulating solution.

In this way, as shown in FIG. 5, the concentration of the circulating solution during heating can be made thinner than the concentration of the circulating solution during cooling.

□. That is, the concentration range that can be changed by the cooling/heating switching/concentration automatic adjustment mechanism during cooling operation is within cycles M and N in FIG. 5.

During cooling operation, refrigerant accumulates in the evaporator U seal 17 and the refrigerant reservoir U seal 18, and the refrigerant reservoir U seal 18
is thick because it serves as a steam circuit during heating, so a large amount of refrigerant accumulates, and when heating operation starts, this refrigerant returns to the circulating solution, so the circulating solution concentration Q during heating operation is thinner than the circulating solution concentration during cooling operation. It will become.

In addition, when cooling operation is started from a state where there is no refrigerant in the air conditioning/heating switching/concentration automatic adjustment mechanism during heating operation, the refrigerant condensed in the condenser 3 is transferred to the evaporator U seal 17 and the refrigerant reservoir U seal 1.
8 is naturally sealed with liquid, allowing cooling operation.

Although the above explanation is for a single-effect absorption refrigerator, it goes without saying that the same holds true for a double-effect absorption refrigerator.

As mentioned above, according to the absorption refrigerator of the present invention, it is possible to efficiently switch between heating and cooling and automatically adjust the concentration of the solution using a simple mechanism incorporated between the condenser and the evaporator. It is possible to obtain rich functionality with an inexpensive structure.

In particular, in the absorption refrigerator of the present invention, a constant liquid level device having an overflow part and a reservoir part is provided, and the reservoir part and the refrigerant reservoir are connected by a thick U-shaped conduit, so that the differential pressure varies. Even during this period, the refrigerant in the U-shaped conduit does not escape to the evaporator, and a constant liquid level is always maintained in the reservoir of the constant liquid level device, allowing the concentration of the solution to be adjusted according to the operating conditions. This can be done reliably, and since the refrigerant can be retained even when the operation is stopped, it not only contributes to energy saving but also has the advantage that the operation can be restarted easily and smoothly.

Furthermore, the condenser and constant liquid level device are connected through a thick channel,
Since the liquid overflowing from the constant liquid level device is sent to the evaporator through a thin U-shaped conduit, a sufficient pressure difference is maintained between the space on the condenser side and the evaporator, and the evaporation in the evaporator is maintained. It also has the advantage of being efficient.

[Brief explanation of the drawing]

Figure 1 is a system diagram of an absorption refrigerator before incorporating the heating/cooling switching and automatic concentration adjustment mechanism, Figure 2 is a system diagram of an absorption refrigerator incorporating the heating/cooling switching and automatic concentration adjustment mechanism of the present invention, and Figure 3 4 is a vertical sectional view showing a detailed structure of the air-conditioning/heating switching/concentration automatic adjustment mechanism, FIG. 4 is a longitudinal sectional view showing a part of FIG. 3 in detail, and FIG. 5 shows the characteristics of the absorption refrigerator according to the present invention. This is a graph showing. 1. Regenerator, 2. Separator, 3. Condenser, 4. Evaporator, 5. Absorber, 6. Heat exchanger, 7.8. Cooling pipe, 9. Cooling tower. , 10. Cooling water circulation pump, 11.
・Cold/hot wood pipe, 12.・Air conditioner, 13.・Cold/hot water circulation pump, 14.・Heater, 15.・Introduction pipe as a flow path.
16... Constant liquid level device, 16a... Overflow part, 1
6b... Reservoir part, 17... Evaporator U as a U-shaped conduit
Seal, 18... Refrigerant reservoir U seal as a U-shaped conduit,
19. Refrigerant reservoir, 20. Connecting pipe as flow path, 21.
・Refrigerant return pipe, 22...Pressure equalization hole.

Claims (1)

[Scope of utility model registration request] Regenerator 19 Separator 2. Condenser 3. Evaporator 4. Absorber 5.
In an absorption refrigerator consisting of a heat exchanger 6, the condenser 3
An overflow part 16a and a reservoir part 16b are used to maintain a constant liquid level.
and an opening of a first conduit 17 for guiding the overflowing liquid from this to the evaporator 4, and a reservoir 16b of this constant liquid level device 16. A refrigerant reservoir 19 communicated with a second conduit 18 is provided, a thick channel 20 is connected to the evaporator 4 from the upper side of the refrigerant reservoir 19, and the first conduit 17 is connected to a thin U-shaped conduit. An absorption refrigerator having a heating/cooling switching and automatic concentration adjustment mechanism, characterized in that the second conduit 18 is formed as a thick U-shaped conduit.