JPH0694966B2 - Adsorption refrigerator - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an adsorption refrigerating machine that performs a refrigerating operation by utilizing a refrigerant adsorbing / desorbing action of an adsorbent, and more particularly to condensation on the bottom of a body of the adsorption refrigerating machine. The present invention relates to the adsorption type refrigerating apparatus provided with means for preventing the refrigerant liquid from adhering, evaporating during the adsorption operation, cooling the body, and causing energy loss.

(Prior Art) The problem of global depletion of energy resources in recent years is a very serious problem for the future of Japan, which is poor in energy resources. Especially, wasteful use of energy resources will be severely managed in the future. There is a need.

By the way, among these energy resources,
Cooling water after high temperature heat recovery at a thermal power plant or a low temperature heat source of 80 ° C or less that is generated secondarily in chemical factories etc. is completely used due to problems such as efficiency of recovery equipment and recovery cost. The current situation is that they are discarded without any action.

Also, in the field of solar thermal energy utilization technology, which is being developed with the aim of obtaining clean energy, it is necessary to use a low-temperature heat medium of 80 ° C or less that can be easily obtained with a flat plate collector as a heat source for cooling operation. However, it is known that it is most advantageous in terms of equipment cost and running cost, but even in this case, in the cooling system using the conventional absorption refrigerator, the temperature of the heat source is low, which is common. Air conditioning system temperature conditions (cooling water inlet temperature 30
℃, cooling inlet temperature 12 ° C, cooling outlet temperature 7 ° C) could not be fully exerted, and the equipment cost was inevitably soaring due to the enlargement of the refrigerator.

Therefore, recently, instead of the conventional absorption chiller, it is being reconsidered to incorporate an adsorption chiller that applies a refrigerant adsorption / desorption action of an absorbent such as silica gel or zeolite into an air conditioning system.

FIG. 5 is a sectional view showing an example of such an adsorption refrigerator.

This adsorption refrigerator has a fin-shaped heat transfer tube (2) for passing a heat medium obtained by a solar energy collector or the like inside a horizontally long vacuum container (1) in which a certain amount of refrigerant is sealed.
And evaporative condensation plates (4), (4) 'integrated with the linear manifolds (3), (3)' for passing the heat medium on the use side
And are horizontally installed at a required interval, and the evaporative condensation plates (4) and (4) 'are surrounded by cylindrical divergence-proof shields (5) and (5)', and Heat tube (2)
Zeolite in the facing gap of fins (6) on the outer periphery of
It has a structure in which a solid adsorbent (7) such as activated carbon, activated alumina or silica gel is attached, and during desorption operation,
When a fluid supplied from a heat source is passed through the heat transfer tube (2) to heat and desorb the solid adsorbent (7), the refrigerant vapor desorbed from the solid adsorbent (7) is evaporated and condensed (4). , (4) 'is condensed on the surface and adheres to it. In addition, during the adsorption operation, when cooling water is flowed through the heat transfer tube (2) to cool the solid adsorbent (7), the solid adsorbent (7) becomes a refrigerant vapor in the vacuum container (1) and Since the refrigerant on the surfaces of the evaporative condenser plates (4), (4) 'is adsorbed, the evaporative condenser plates (4), (4),
(4) 'takes heat from the evaporative condensate (4), (4)'
The heat medium on the utilization side that passes through the inside of the linear manifolds (3) and (3) 'integrated with

Thus, the above-mentioned adsorption / desorption is alternately repeated, and the cooled user-side heat medium is used for air conditioning of a building or the like. (JP-A-60-
(See Japanese Patent No. 36852) (Problems to be solved by the invention) However, in the adsorption refrigerator having the above-described conventional structure, a temperature difference between the cooling water inlet and the cooling water outlet on the evaporative condenser side during the adsorbent desorption operation. Therefore, the refrigerant condensation amount, that is,
The thickness of the refrigerant liquid film on the condenser surface varies, and the evaporation speed becomes slow at the part where the liquid film becomes thicker than the set thickness, and the adsorption / desorption cycle time becomes longer and the refrigerant liquid that cannot be held Has fallen to the bottom of the body and adhered to the inner surface, which is consumed as wasted energy for cooling the body during the adsorption operation, and is not output as refrigeration capacity, resulting in a decrease in the efficiency of the entire apparatus.

The present invention was made by focusing on the problem of the refrigerating capacity deterioration caused by the variation of the refrigerant liquid film thickness of the evaporative condensation surface in such a conventional adsorption refrigerator, and the refrigerant dropped at the bottom of the body during desorption operation By heating and returning to the vapor state again, by utilizing the fact that the heat transfer coefficient is inversely proportional to the size of the refrigerant liquid film thickness, more refrigerant is condensed in the thin portion of the refrigerant liquid film, and the liquid film thickness is vaporized. The object of the present invention is to eliminate the above-mentioned problems by making the entire condenser uniform to increase the evaporation speed during the adsorption operation, eliminate energy loss and improve the efficiency of the entire absorption refrigerator.

(Means for Solving Problems) The configuration of the present invention for achieving the above object will be described in detail with reference to FIGS. 1 and 2 corresponding to the embodiment.

The vacuum fuselage (11) in which a predetermined amount of refrigerant is sealed has a first fin flute (12) through which a heat source side heat medium passes.
And a second finch tube (1
4) and are housed in the first finch tube (12)
The fin gap is filled with and held by an adsorbent (18) such as granular silica gel.

The adsorption refrigerator having the above structure further includes a refrigerant heater (22) for heating the refrigerant that drops from the second fin tube to the bottom of the body when the adsorbent is desorbed at the bottom of the body (11). At the same time, the amount of refrigerant enclosed in the body (11) is set to the minimum necessary within the operating temperature range under constant operating conditions.

The refrigerant heater (22) includes an electric heater and the like in addition to a hollow hot water tank for supplying the heat medium on the heat source side to heat the refrigerant from the bottom of the body.

(Operation) In the absorption refrigerating machine of the present invention having the above-described configuration, during the desorption operation, the heat medium on the heat source side is passed through the first finch tube (12) to heat and desorb the adsorbent (18). Cooling water is passed through the fin chute (14) to condense the refrigerant vapor desorbed from the adsorbent (18) on the surface of the second fin chive (14) to form a refrigerant liquid film. Since the cooling water flowing through the fin chute (14) has a temperature difference between the inlet and the outlet, the thickness of the refrigerant liquid film varies, and from the portion where the liquid film becomes excessive, the bottom of the body (11) Refrigerant liquid that is no longer retained in the device drips. However, a refrigerant heater (22) is provided at the bottom of the body (11), and the refrigerant heats and evaporates and returns to the refrigerant vapor again, and the thin portion of the refrigerant liquid film is thick on the surface of the second fin tube (14). The heat transfer coefficient is better than that of the portion, and more cooling vapor is condensed, so that the liquid film thickness is averaged throughout.

At this time, the amount of the refrigerant enclosed in the body (11) is the minimum necessary in the operating temperature range under the preset operating conditions, so that the total amount of the refrigerant liquid is the surface of the second fin tube (14). It is uniformly held in a liquid film state.

Thus, during the adsorption operation, the heat medium on the utilization side is passed through the second finch tube (14) that holds the refrigerant evenly,
When the adsorbent (18) is cooled by passing the cooling water through the first fin chute (12), the adsorbent (18) adsorbs the refrigerant vapor inside the body (11) and the refrigerant from the second fin chute (14). To remove the heat of vaporization from the heat medium on the side of use and cool it, the evaporation speed of the second fin chute (14) becomes uniform, the adsorption / desorption cycle time is shortened, and the refrigerant liquid is transferred to the bottom of the body. It is possible to improve the efficiency of the apparatus by eliminating the problem that the body adheres to the surface and cools the body at the time of adsorption to cause energy loss.

Embodiment An embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a front sectional view of an adsorption refrigerator according to the present invention, FIG. 2 is a side sectional view of the adsorption refrigerator, and FIG. 3 is a circuit of a cooling system to which the adsorption refrigerator is applied. , (A) shows the state during desorption operation, and (b) shows the state during adsorption operation.

In these figures, (11) is a body forming the main body of the adsorption refrigerator, and (12) is a thin cross fin type heat exchanger housed in the internal space (13) of the body (11). First
, A second finch tube (14) arranged in parallel with the first finch tube (12) at a required distance and serving as a condenser and an evaporator, and (15) inside the body (11). A pressure sensor for detecting pressure, wherein a required amount of water or the like is enclosed as a refrigerant in the body (11), and an internal space (13) of the body (11).
Is kept in a vacuum.

The first finch tube (12) has a vertical heat transfer tube (1
On the outer surface of 6), a number of horizontal fins (1
7) is attached, and the fin gaps (1 to 10 mm for fin pitch, 5 to 20 mm for fin height) on the outer circumference of the heat transfer tube (16) are filled with a solid adsorbent (18) such as granular silica gel. It is held by wire meshes (19) and (19) 'stretched on the front and back surfaces of (12). Also,
The second finch tube (14) is a cross fin type heat exchanger similar to the first finch tube (12), and the fins (21) provided on the outer circumference of the heat transfer tube (20) are kept substantially horizontal. Thus, the water condensed on the surface can be retained in a liquid film state having a uniform thickness.

On the other hand, at the bottom of the body (11), a warm water tank (22) for heating the bottom surface (11a) of the body by passing warm water.
It is equipped with.

The amount of the refrigerant enclosed in the body (11) is the minimum necessary amount within the operating temperature range under the preset operating conditions, that is, the amount of the refrigerant on the surface of the second fin chute (14) at the time of completion of desorption. Almost all the amount is retained in the liquid film state,
Moreover, the total amount is defined as the amount adsorbed by the adsorbent (18) when the adsorption is completed.

In the adsorption refrigerator having the above structure, the inlet port (12a) provided in the first finch tube (12) is a three-way valve.
(V ₁ ) via a heat medium outlet (23) of a low temperature heat source (23) such as a solar energy collector, a boiler or a heat exchanger for waste heat recovery.
a) and the cooling water outlet (24a) of the cooling water supply source (24) such as a cooling tower are maintained via pumps (P ₁ ) and (P ₂ ) respectively, and the outlet port (12b) is a three-way valve. It is connected to the heat medium inlet (23a) of the low temperature heat medium (23) and the cooling water inlet (24b) of the cooling water supply source (24) via (V ₂ ).

The inlet port (14a) of the second winch tube (14) is a pump (P) that pumps the heat medium on the utilization side from the heat storage tank (25) via the _three- way valve (V3) through the pipe (26). ₃ ) and the discharge port of the pump (P ₂ ) and
The outlet port (14b) is connected via the three-way valve (V ₄ ) to the heat storage tank (2
A pipe (27) for supplying the heat medium on the utilization side to 5) and a cooling water inlet (24b) of the cooling water supply source (24) are respectively connected.

The heat storage tank (25) is a tank whose upper portion is divided into a low temperature tank (29) and a high temperature tank (30) by a partition wall (28) through which a fluid can pass, and a pump (P ₄ ), The 7 ° C use side heat medium is constantly supplied to the air conditioning heat exchanger (31), and the heat medium whose temperature has risen to 12 ° C is returned to the high temperature tank (30). It absorbs the difference in circulation amount between (P ₃ ) and the pump (P ₄ ), stores the heat medium supplied from the adsorption refrigerator, and cools it to the air conditioning target area during the rest time (time required for desorption). Has the role of continuously supplying cold heat.

On the other hand, the hot water tank (22) provided at the bottom of the body (11) has its inlet (22a) connected to the discharge side of the pump (P ₁ ) and its outlet (22b) at a low temperature heat source (23). ) Is connected to the heat medium inlet (23b).

The refrigerant adjusting device of the present invention has the above-mentioned configuration. Next, its operation will be described step by step.

First, during the desorption operation shown in FIG.
Drive (P ₁ ) and heat medium (60-80 ℃) from the heat medium outlet (23a) of the low temperature heat source (23) through the three-way valve (V ₁ ) to the inlet port (12a) of the first finch tube (12). By heating and desorbing the adsorbent (18), the pump (P ₂ ) is driven, and the _second source is supplied from the cooling water supply source (27) via the three-way valve (V ₃ ).
When the cooling water (30 to 32 ° C.) was supplied to the finch yube (14) of this, and the finch yuve (14) was cooled, it was discharged into the internal space (13) of the body (11) by the desorption of the adsorbent (18). The refrigerant vapor condenses on the surface of the second fin tube (14) and forms a liquid film on the surfaces of the fin (21) and the heat transfer tube (20).

At this time, on the surface of the second fin tube (14), there is a temperature difference in the cooling water between the inlet port (14a) and the outlet port (14b), which causes variations in the thickness of the refrigerant liquid film. The refrigerant liquid that has become too thick to hold due to excessive liquid film thickness forms drops of water on the bottom surface (11a) of the body (11), but the warm water tank (22) below the body (3) has three sides. Valve (V ₅ )
Through the low temperature heat source (23)
The heat medium (60 to 80 ° C) is supplied in parallel with 2), the refrigerant is heated and returns to steam again, and the portion of the surface of the second fin tube (14) where the refrigerant liquid film thickness is thin. Has a better heat transfer coefficient than the thick part of the liquid film, and more refrigerant vapor condenses, so
It will be formed on average over the whole.

Further, since the amount of the refrigerant inside the body (11) is regulated to the minimum necessary in the operating temperature range under the preset operating condition, the entire amount is condensed on the surface of the second fin chute (14) and the body ( The refrigerant liquid is prevented from adhering to the bottom surface (11a) of 11) and the inner peripheral surface.

Next, the state during the adsorption operation shown in FIG. 3B will be described.

Drive the pump (P ₂ ) and use the three-way valve (V
₁ ) through cooling water (30 ~
(32 ° C.) to cool the adsorbent (18) to adsorb the refrigerant vapor in the body (11).
The refrigerant adhering to the surface of (4) evaporates in the body (11) and removes the heat of vaporization from the finch tube (14) to the pump (P
_The heat on the side of use of 12 ° C, which is pumped from the high temperature tank (30) of the heat storage tank (25) through the pipe (26) by the operation of ₃ ) and is supplied to the second finch ube (14) via the _three- way valve (V ₃ ). A pump to cool the medium to about 7 ° C and supply it to the low temperature tank (24) of the heat storage tank (25) from the three-way valve (V ₄ ) through the pipe (27).
(P ₄ ) activates the heat storage tank (25) to the heat exchanger (3
The heat transfer medium of about 7 ℃ is supplied to 1), and the heat medium that takes sensible heat from the air and heats up to 12 ℃ recirculates to the high temperature tank (33). Perform air conditioning.

In the above embodiment, as the refrigerant heater (22) provided at the bottom of the body (11), a hot water tank for heating the refrigerant by supplying the heat medium on the heat source side of the low temperature heat source (23) is used. Although exemplified, the hot water tank (22) can be replaced with an electric heater, a far infrared heater, or the like.

In addition, in the above embodiment, the heat storage tank (25) is provided between the adsorption refrigerator and the air conditioner heat exchanger (31) for the purpose of supplementing the desorption time. When it takes a long time, it is possible to carry out continuous operation by using two or more of the adsorption type refrigerators instead of this and alternately performing adsorption operation and desorption operation.

A prototype of a device having substantially the same type as that of FIG. 1 and FIG.
An experiment was conducted to compare the case of using the refrigerant heater and the case of not using the refrigerant heater during the desorption operation.

The operating conditions are as follows.

Experimental Results When a refrigerant heater is used (present invention) ... (A) When a refrigerant heater is not used (conventional) ... (B) The difference in the speed at which the adsorbent adsorbs the refrigerant during the adsorption time (3.5 minutes) is as shown in the graph of FIG.

As is clear from the above results, when the refrigerant heater is used (the present invention), the adsorption / desorption cycle time is about 20% faster than when it is not used (conventional), and the amount of the adsorbed / desorbed refrigerant is about 20% faster.
It was confirmed that the refrigerating capacity output to the outside was increased by about 30% and about 50%.

(Effects of the Invention) As described above, the adsorption refrigerator according to the present invention is provided with the refrigerant heater for heating and evaporating the refrigerant dripping from the second fin tube to the bottom of the body when the adsorbent is desorbed to the bottom of the body. Since the amount of refrigerant charged inside the fuselage is regulated to the minimum necessary within the operating temperature range under constant operating conditions, the total amount of refrigerant desorbed from the adsorbent is uniform over the entire surface of the fin coil on the condenser / evaporator side. Since it will be retained in a liquid film, the evaporation speed during adsorption operation will be uniformized, the adsorption / desorption cycle time will be shortened, and the refrigerant liquid dropped on the bottom of the fuselage cannot be retained during desorption. It is possible to overcome the inconvenience that it is consumed as wasted energy that evaporates during adsorption and cools the body, and it has the excellent effect of greatly improving the efficiency of the adsorption refrigerator. It

Moreover, according to the present invention, a refrigerant heater is added, and
Since it is possible to improve the capacity of the entire adsorption refrigerator as described above just by defining the amount of refrigerant to be filled, the refrigerator capacity can be reduced accordingly, and the device cost can be reduced, and in particular When a low-temperature heat source is used as the heat source for the refrigerant heater, it is expected that the operating cost will be prevented from soaring, the low-temperature heat source will be effectively used, and energy resources will be saved.

[Brief description of drawings]

FIG. 1 is a front sectional view of an adsorption refrigerator according to the present invention, FIG. 2 is a side sectional view of the adsorption refrigerator, and FIG. 3 is a circuit diagram of a cooling system to which the adsorption refrigerator is applied. (A) shows the state during the desorption operation, and (b) shows the state during the adsorption operation. Fig. 4 is a graph comparing the adsorption speed of the adsorption refrigerating machine of the present invention with that of the conventional adsorption refrigeration machine, and Fig. 5 is a sectional view of the conventional adsorption refrigeration machine. (11) ... Body, (11a) ... Bottom surface, (12) ... First finch tube, (14) ... Second finch tube, (18) ... Adsorbent, (22) ... Refrigerant heater (hot water tank),

Claims (4)

[Claims] 1. A first fin tube for passing a heat medium on the heat source side and a second fin tube for passing a heat medium on the utilization side are housed inside a vacuum body containing a predetermined amount of refrigerant.
An adsorption type refrigerator in which the fin gap of the first fin tube is filled and held with an adsorbent, wherein the refrigerator drips from the second fin tube to the bottom of the body when the adsorbent is attached to and detached from the bottom of the body. And a refrigerant heater that heats and evaporates the refrigerant to be heated, and the amount of the refrigerant enclosed in the body is set to a necessary minimum within an operating temperature range under constant operating conditions. 2. The amount of the refrigerant enclosed in the body is regulated so that the entire amount is retained in a liquid film state on the surface of the second fin tube when the desorption is completed, and the entire amount is adsorbed by the adsorbent when the adsorption is completed. An adsorption refrigerator according to claim 1. 3. The adsorption refrigerator according to claim 1 or 2, wherein the refrigerant heater is a hot water tank provided in contact with the bottom surface of the body. 4. The adsorption refrigerator according to claim 1, wherein the refrigerant heater is an electric heater provided in contact with the bottom surface of the body.