JPS6249539B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel absorption refrigerating machine that can be simplified and made more compact by omitting a rectifier and an analyzer.

Conventional absorption refrigerators use ammonia and
There are ammonia-water refrigerators that use water as an absorbent, and water-LiBr refrigerators that use water as a refrigerant and lithium bromide liquid as an absorbent, but the former has a temperature below 0°C compared to the latter. Although it has the advantage of being able to be cooled to a considerably lower temperature,
In order to improve efficiency, a rectifier 1 is installed as shown in Figure 1.
3 and an analyzer 14 to separate the water vapor mixed in the ammonia gas evaporated by the generator 8 and to prevent water from entering the condenser 3 and evaporator 1. However, it had the disadvantage of having a complicated structure.

On the other hand, in the latter case, although the rectifier 13 and analyzer 14 are unnecessary, since the interior is kept in a high vacuum, it is easy for non-condensable gases such as air to enter, which prevents the refrigeration effect from decreasing. At the same time, a bleed air recovery device is required to prevent crystal precipitation.
The drawback was that it was cumbersome to handle, such as having to operate the vacuum pump automatically.

The present invention aims to eliminate the drawbacks of the conventional refrigerators mentioned above, to simplify the structure, to simplify handling, and to provide a new absorption refrigerator which can function to improve efficiency. It is characterized by the fact that it uses ammonia as a refrigerant and an ammine complex as an absorbent.

The refrigerator of the present invention will be explained in detail below based on the accompanying drawings.

Currently, a combination of ammine complex and ammonia has been proposed as a chemical reactant for a thermal energy storage system (chemical heat pump system) that utilizes a reversible thermochemical reaction cycle.
As an example, CaCl ₂・4NH ₃ CaCl ₂・2NH ₃ +2NH ₃ △H=125.0Kcal/Kg (43℃) MgBr ₂・6NH ₃ MgBr ₂・2NH ₃ +4NH ₃ △H=134Kcalml/Kg (12℃) be.

They generate heat of formation when two substances react to form a compound, and absorb the heat of decomposition to decompose into the two original substances. It utilizes heat generation and absorption.

On the other hand, ammonia-water systems utilize the difference in the amount of ammonia dissolved in the absorbent (water), and the pressure (P)-temperature (1/T) characteristics of the two are the same as those of ammonia-sodium iodide. The ammine complex system is shown in Figure 4, and the ammonia-water system is shown in Figure 2.

In the former NH ₃ - NaI system, the reaction expressed by the general formula NaI・n ₁ NH ₃ + n ₂ NH ₃ NaI (n ₁ + n ₂ ) NH ₃ takes place,
For example, at 35℃, 1.5Kg/cm ² of NaI・3.5NH ₃ at 35℃,
When 4.2Kg/cm ² of ammonia is applied,
_NaI5.0NH3 .

NaI・3.5NH ₃ +1.5NH ₃ NaI・5.0NH ₃ (35℃, 4.5Kg/cm ² ) This reversible thermochemical reaction is similar to the ammonia-water system and is different from the reaction of the lithium bromide-water system under negative pressure. It has an important feature in that it is carried out within a positive pressure region.

The basis of the present invention is to use such a reversible thermochemical reaction cycle to perform the freezing action. When ammonia is absorbed by the ammine complex, heat is generated, and the It is easy to understand that the phenomenon of heat absorption when ammonia decomposes corresponds to a refrigeration cycle that takes heat from the object to be cooled and releases this heat to the outside of the system.

Examples of the structure of the refrigerator of the present invention are shown in FIGS. 3A and 3B. To explain the structure of FIG. 3A, 1 is an evaporator, 2 is a collector that collects solar heat, is a condenser, 4 is an absorber, 5 is a cooling fan, 6 is a solution pump, 7 is a solution flow rate regulator, 8 is a generator, 9 is an expansion valve, 10 is a solution heat exchanger, 11
is a four-way switching valve, 12 is a heat storage tank, and heat collector 2
Other equipment except for the heat storage tank 12 is assembled integrally.

The heat collector 2 is a heat source device for forming an absorption refrigeration cycle, but it can of course be replaced with a heater using city gas, an electric heater, or an exhaust heat recovery device, or it can be replaced with a heater or an electric heater. may be installed alongside the heat collector 2 and used as an auxiliary heat source during rainy days and at night.

To explain the refrigeration operation of this refrigerator with the structure shown in Fig. 3A, the refrigerant (n ₂ NH ₃ ), which is evaporated by exchanging latent heat of evaporation with cold water in the evaporator 1, is transferred to the four-way switching valve. It flows into the solution flow rate regulator 7 through the solution flow rate controller 7 through the solution heat exchanger 11, and after combining with the concentrated solution (NaI·n ₁ NH ₃ ) sent from the generator 8 via the solution heat exchanger 10, it is sent into the absorber 4.

In the absorber 4, the latent heat of condensation generated when the refrigerant liquefies and the reaction heat generated when the refrigerant is absorbed by the concentrated solution and reacts are released into the atmosphere by the cooling fan 5.

The dilute solution (NaI・(n ₁ +
n ₂ )NH ₃ ) is pumped by the solution pump 6 into the solution heat exchanger 10 and exchanges heat with the concentrated solution leaving the generator 8 to save the amount of heat required by the generator 8.

On the other hand, since the concentrated solution leaving the generator 8 is cooled by this dilute solution, the cooling capacity required in the absorber 4 is reduced.

The dilute solution exiting the solution heat exchanger 10 enters the generator 8 after being heated, and passes through the bottom and the heat collector 2 communicating therewith.
When heated by the sun's heat, it decomposes into a refrigerant and a concentrated solution. Thus, the refrigerant evaporates and the solution is regenerated.

This regenerated concentrated solution is sent to the solution heat exchanger 10 as described above.

The refrigerant generated in the generator 8 passes through the four-way switching valve 11 to the condenser 3, is sent by the cooling fan 5, releases heat to the wind that passes through the absorber 4, condenses and liquefies, and then expands. The pressure is reduced by the valve 9, the water flows into the evaporator 1, and the steps from evaporation are repeated to complete the refrigeration cycle.

Here, a closed circulation system is formed between the generator 8 and the heat collector 2, and the heat collector 2 is larger than the generator 8.
By arranging the dilute solution at a low position, the dilute solution is heated in the heat collector 2 and decomposed into a refrigerant and a concentrated solution.
The generated refrigerant gas rises in the generator 8 along with the concentrated solution by a bubble pump action, and accumulates in the upper part of the generator 8 while exchanging the low concentration liquid and the high concentration liquid in the heat collector 2. . On the other hand, the concentrated solution rises along with the refrigerant gas in the heat collector 2, is extracted, and accumulates in the lower part of the generator 8, where natural circulation is performed by gas-liquid separation. This explanation can be explained on the temperature-pressure diagram of the solution shown in FIG. 4 as follows.

The points indicate the state points of the refrigerant NH ₃ in the evaporator 1,
The steam generated here reaches the absorber 4 and the generator 8
The solution flows out from the solution heat exchanger 10 and is absorbed by the solution after heat exchange (hereinafter referred to as solution), and the heat generated at that time is dissipated to the outside air, and the solution becomes a solution. The solution is pumped up by pump 6 and transferred to heat exchanger 1.
After heat exchange at 0, the temperature and pressure of the solution reach the generator 8. The solution flowing into the heat collector 2 from the generator 8 is heated, releases ammonia refrigerant, increases its concentration, becomes a solution, and flows out to the generator 8 again. The refrigerant gas released at this time is sucked into the condenser 3 and is condensed and liquefied at a point. The liquefied refrigerant becomes a dot while passing through the expansion valve 9 and returns to the generator 1.

That is, the solution is circulated by ..., and the refrigerant gas is circulated by ....

In addition, during heating operation, the condenser 3 is used as a heat exchanger for evaporation, and the refrigerant gas (n ₂ NH ₃ ) that has taken the heat from the outside air and evaporated passes through the four-way valve 11 as shown by the dotted line and changes the solution flow rate. It flows into the regulator 7, merges with the concentrated solution (NaI·n ₁ NH ₃ ) from the generator 8, and is sent to the absorber 4. The absorber 4 absorbs the refrigerant gas, and the diluted diluted solution (NaI・(n ₁ + n ₂ )NH ₃ ) is circulated by the solution pump 6 to the generator 8 via the solution heat exchanger 10 to collect heat. It is heated in vessel 2 and decomposed into a refrigerant and a concentrated solution. The refrigerant generated in the generator passes through the four-way valve 11 to the evaporator 1, where it is used as a heat exchanger for condensation in the evaporator, dissipates heat into the hot water of the heat medium on the user side, condenses, and expands. It is depressurized through valve 9 and enters condenser 3 to complete the cycle.

To explain the refrigeration operation with the structure shown in FIG. 3B, the refrigerant (n ₂ NH ₃ ) that is evaporated by removing latent heat of vaporization from the cold water in the evaporator 1 flows into the absorber 4, and the concentrated solution ( It merges with NaI・n ₁ NH ₃ ) and is absorbed, and the heat generated during absorption is released into hot water. The dilute solution (NaI・(n ₁ + n ₂ )NH ₃ ) generated in the absorber 4 is sent out by the solution pump 6 and eventually reaches the generator 8, and is further circulated between this and the heat collector 2. However, when heated by solar heat, it decomposes into a refrigerant and a concentrated solution.

The refrigerant generated in the generator 8 reaches the condenser 3, where it releases the heat of condensation into hot water and is condensed and liquefied.As it passes through the expansion valve 9, the pressure drops and reaches the evaporator 1, completing the refrigeration cycle.

In addition, when freezing, use the cold water on the outlet side of the evaporator.
The heat on the hot water side is released to the atmosphere, the hot water on the outlet side is used for heating, and the cold water side is replenished with heat from the atmosphere.

In this way, absorption refrigeration operation is carried out using solar heat as a heat source, but the ammine complex of sodium iodide has a liquid phase region and a solid phase region as shown in Figure 5, so it is not necessary to operate at all temperatures. Although it cannot be used in a pressure range, as long as it is used in a liquid phase region, absorption and generation will occur under a positive pressure higher than atmospheric pressure.

In addition, since the ammine complex does not contain other volatile fluids such as water, it does not require any separation equipment such as a rectifier or analyzer, and since the system is under positive pressure, there is no intrusion of air and no air is extracted. No equipment required.

As described above, the present invention uses ammonia as a refrigerant and an ammine complex as an absorbent in an absorption refrigerating machine, so as mentioned above, the rectifier and analyzer can be omitted, greatly simplifying the apparatus. .

Furthermore, since the system is under positive pressure, there is no air intrusion and stable operation is possible.
Since a thermally stable refrigerant is used, a high-performance absorption refrigerator can be provided.

Moreover, since refrigerant gas has a higher pressure and a higher gas density than water etc., the differential pressure for circulation can be increased and the cross-sectional area of the flow path can be reduced, making it possible to use an air-cooled structure, and the required amount of refrigerant. Since only a small amount of absorbent is required, it can be sufficiently used for home use.Furthermore, since the specific gravity of the absorbent is large and the absorption rate is high, the required amount of absorbent is reduced and the device can be made smaller, resulting in excellent practical effects.

[Brief explanation of the drawing]

Figure 1 is a schematic structural diagram of a conventional absorption refrigerator, Figure 2 is a pressure-temperature diagram of the ammonia-water system, and Figure 3 is a diagram of the pressure-temperature diagram of the ammonia-water system.
Figures A and B are schematic structural diagrams of an example of the refrigerator of the present invention;
FIG. 4 is a pressure-temperature diagram, and FIG. 5 is a phase change diagram with respect to temperature and pressure of the ammine complex used in the refrigerator of the present invention. 1...evaporator, 3...condenser, 4...absorber, 8...generator.

Claims (1)

[Scope of Claims] 1. A condenser 3 and a generator 8 are provided on the high pressure side, and an evaporator 1 and an absorber 4 are provided on the low pressure side, and ammonia is used as a refrigerant and an ammine complex is used as an absorbent. An absorption chiller featuring: 2. The absorption refrigerator according to claim 1, wherein the absorbent is an ammine complex of sodium iodide.