JP3138784B2 - Adsorption refrigeration system with heat storage function and its operation method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adsorption type refrigeration system suitable for a cogeneration system, and more particularly, to a system having a temperature lower than the atmospheric temperature by using a low level exhaust heat source discharged from a gas engine or the like. The present invention relates to an adsorption-type refrigeration system having a heat storage function, which can store thermal energy, take it out when necessary, and use it for a low-temperature heat source such as cooling, and a method of operating the same.

[0002]

2. Description of the Related Art In recent years, as a part of an energy saving system, a so-called cogeneration system in which a generator is rotated by a gas engine or the like, and at the same time, refrigeration equipment or the like is driven by exhaust heat of the gas engine has attracted attention. By the way, cogeneration systems are generally designed for the daytime when power and heat demands are sufficient, so that efficient operation can be performed at night when there is only a large demand for power and little heat demand. Many users use this system only in the daytime and switch to power purchase at night. However, the operation time of the cogeneration system has been shortened, and the depreciation period has been lengthened accordingly. As a result, there are many cases in which the introduction of the system is delayed.

Therefore, it is required that the cogeneration system can be operated efficiently even at night, and as a solution to this problem, for example, Japanese Utility Model Laid-Open No. 3-46165 discloses
A cogeneration system with a heat storage function is described. Specifically, at night or the like when there is no demand for heat, the absorption refrigerator is operated using the exhaust heat discharged from the engine system as a heat source, and the cold generated at that time is stored in a heat storage tank as cold water, and this is stored. This system can be used when cold heat is required, such as during the day.

[0004]

However, in the case of this system, even if the above-mentioned operational problem is solved, since the heat storage method is to store cold heat generated by the refrigerator as sensible heat, heat is stored. There was a problem that the tank became large and the system became huge. The present invention addresses such a situation, and proposes a refrigeration system using an adsorption-type refrigerator in which heat is stored by changing the phase of a heat storage material during heat storage, to reduce the size and weight of the heat storage tank. The purpose is to contribute to the further spread of cogeneration systems.

[0005]

That is, a feature of the present invention that meets the above-mentioned object is that a plurality of adsorption towers filled with an adsorbent are used, and a condenser and an evaporator are provided so that a refrigerant can circulate in each adsorption tower. Along with the evaporator of the adsorption refrigerating machine operated to switch the adsorption and desorption processes so that at least one of the adsorption towers is in a different step from the other, and the refrigerant of the adsorption refrigerating machine, A heat storage tank filled with a material with a high freezing point as a heat storage material is connected by a pipe that circulates a heat medium,
A cooling heat extraction unit is connected in parallel in the middle of the pipe via a three-way valve to constitute an adsorption refrigeration system having a heat storage function.

The inventions described in claims 2 and 3 specifically show the adsorbent, activated carbon and refrigerant in the above configuration. In the case of claim 2, activated carbon as the adsorbent, alcohol as the refrigerant, Water is used as the heat storage material, and the invention according to claim 3 is characterized in that silica gel is used as the adsorbent, water is used as the refrigerant, and clathrate is used as the heat storage material.

The invention according to a fourth aspect of the present invention relates to a method of operating the refrigeration system, wherein the heat storage material is solidified by circulating the cold output from the evaporator through the heat medium into the heat storage tank. An operation method in which the three-way valve is switched and then the three-way valve is switched, and the cold heat output from the evaporator and the stored cold heat, or only the stored cold heat, is extracted from the cold heat extraction unit to the utilization side via a heat medium. It is characterized by.

[0008]

When the system of the present invention is operated according to the above-described method of the present invention, the cold generated by the adsorption type refrigerator is transmitted to the heat storage tank by the heat medium pipe, whereby the heat storage material in the heat storage tank undergoes a phase change and the cold heat is generated. Is stored. At this time, due to the difference in the freezing point between the heat storage material and the refrigerant, the refrigerant does not solidify in the adsorption refrigerator even with the solidification of the heat storage material in the heat storage tank, and as a result, the refrigerator has no inconvenience. Cold heat is continuously generated, and the heat storage proceeds smoothly.

In addition, unlike an absorption refrigerator or the like, an adsorption refrigerator does not cause crystallization inside, and therefore can generate considerably low-temperature cold heat. Specifically, as described in claim 2, -1 if alcohol is used as the refrigerant.
As described in claim 3, when water is used as the refrigerant, it is possible to output cold heat at a temperature level of 3 ° C. Therefore, the clathrate (solidification point of about 5 ° C.) and water (solidification point of 0 ° C.), which are the heat storage materials in each case, can be sufficiently solidified.

[0010] Further, when utilizing cold heat, by switching the three-way valve interposed in the heat medium pipe, it is possible to easily take out the stored cold heat from the cold heat take-out portion. If this is done, not only the heat stored but also the cold generated by the refrigerator is taken out, and efficient utilization operation is realized.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a piping diagram of the adsorption refrigeration system according to the present invention. In the figure, (1) is an adsorption refrigerator, (2) is a heat storage tank, and (3) is a heat exchanger. (4) is a user-side device connected to the adsorption refrigeration system via the heat exchanger (3).

First, the adsorption refrigerator (1) is a known type provided with a plurality of adsorption towers (5), for example, two adsorption towers (only one of them is shown in the figure). Adsorption tower (5)
A predetermined amount of activated carbon is filled with an adsorbent (not shown), and a heating heat transfer surface (6) and a cooling heat transfer surface (7) are arranged for heating and cooling the adsorbent. Has been established.

The heat transfer surface for heating (6) is a hot water system pipe (8).
When the present system is used as an element of a cogeneration system, for example, an exhaust heat supply mechanism of a gas engine is connected to the end of the hot water system piping (8). On the other hand, the cooling heat transfer surface (7) is connected to a cooling tower (10) via a cooling water system pipe (9). (11), (1)
2) is a hot water pump and a cooling water pump provided in each of the pipes (8) and (9).

In addition, an evaporator (13) and a condenser (not shown) are provided so as to be able to communicate with each adsorption tower (5), and each adsorption tower (5) and these evaporators (13) are provided. A predetermined amount of alcohol is sealed as a refrigerant in a system connecting the condenser and the condenser.

The above refrigerator operates by supplying hot water and cooling water in different orders for each adsorption tower (5) via a hot water system pipe (8) and a cooling water system pipe (9). That is, when heating and cooling of each adsorbent are repeated with hot water and cooling water, the refrigerant is desorbed from one adsorbent and condensed in the condenser, and on the other hand, the evaporator (1) is adsorbed by the other adsorbent.
The refrigerant adhering to 3) is adsorbed, the refrigerant evaporates from the evaporator (13), and a known refrigeration cycle is started.

Next, the heat storage tank (2) stores liquid heat storage material. In this case, for example, a number of ice trays (not shown) are provided inside, and a heat storage material is stored in each ice tray. In the heat storage tank (2), (1
4) is a heat transfer tube, which is disposed around the ice tray.

In the case of the present invention, the selection of the heat storage material to be stored in the heat storage tank (2) is particularly important, and the condition is that the solidification point of the heat storage material is lower than that of the refrigerant of the adsorption refrigerator (1). It is required to be high. For example, when the alcohol is used as a refrigerant, water having a freezing point of 0 ° C. higher than its freezing point of −100 ° C. is used. Also, in general, there are many adsorption refrigerators using water as a refrigerant and silica gel as an adsorbent.
A clathrate with a freezing point of 5 ° C. is used as the heat storage material.

The refrigeration system of the present invention is constituted by the adsorption refrigerator (1), the heat storage tank (2) and the heat exchanger (3). In this case, the adsorption refrigerator is used. A heat medium liquid pipe (15) that circulates through the evaporator (13) of (1) and the heat transfer pipe (14) of the heat storage tank (2) to the heat exchanger (3) is provided. Liquid piping (1
5), a bypass pipe (16) that bypasses the heat transfer pipe (14) and a bypass pipe (17) that bypasses the heat exchanger (3) are connected via three-way valves (18) and (19), respectively. Thus, the entire system is configured. In addition,
(20) is a circulation pump for circulating the heat medium liquid.

Next, as an operation method of the adsorption refrigeration system, a heat storage operation performed at night or the like will be described first. In this case, the three-way valve (18) is switched to a direction in which the bypass pipe (16) is closed, that is, a direction in which the heat medium flows through the heat transfer pipe (14). Further, the three-way valve (19) is switched to a direction in which the bypass pipe (17) is opened, that is, a direction in which the heat medium does not flow through the heat exchanger (3).

In this state, when the adsorption type refrigerator (1) is operated and the circulation pump (20) is driven, cold heat of about -10 ° C. is generated in the evaporator (13) of the adsorption type refrigerator (1). This is transmitted to the heat transfer tube (14) via the heat medium, and the heat storage material having a freezing point of 0 ° C. is cooled and changes into ice. As a result, the cold heat is stored in the heat storage tank (2) as ice. In the case where water is used as the refrigerant, cold heat of about 3 ° C. is generated on the side of the refrigerator (1), and this cools the clathrate having a freezing point of 5 ° C. to store heat.

On the other hand, in the utilization operation for extracting cold heat from the heat storage tank (2) during the daytime or the like, a three-way valve (18)
To the direction in which the bypass pipe (16) is opened, that is, the direction in which the heat medium does not flow through the heat transfer pipe (14), and the three-way valve (19) is closed in the direction to close the bypass pipe (17), that is, the heat medium is Switch to the direction of flow through the heat exchanger (3). Then, the circulation pump (20) is driven together with the driving of the refrigerator (1).

By the above operation, the heat medium is supplied to the evaporator (1).
3), reaching the heat exchanger (3) via the heat transfer surface (14), during which the heat storage material in the heat storage tank (2) is thawed, and together with the cold generated by the refrigerator (1), the heat storage cold is generated. Also heat exchanger (3)
Send to As a result, both the cold generated by the refrigerator and the stored cold are extracted to the use side (4).
In that case, if the adsorption refrigerator (1) is stopped, it is possible to take out only the heat storage to the use side (4).
You can choose how to use it.

Further, while operating the adsorption refrigerator (1),
If the three-way valve (18) is switched to the open side of the bypass pipe (16), only the cold generated by the refrigerator (1) can be taken out while keeping the heat storage amount, and the capacity control during the use operation can be easily performed. Will be.

[0024]

As described above, the present invention comprises an evaporator of an adsorption refrigerator and a heat storage tank filled with a substance having a higher freezing point than the refrigerant of the adsorption refrigerator as a heat storage material. It is connected by piping that circulates the heat medium, and since the cold heat extraction unit is connected in parallel via a three-way valve in the middle of the piping, the adsorption refrigerator is driven by exhaust heat during the time when there is no heat demand, The cold heat can be stored, and continuous operation in a waste heat utilization system such as a cogeneration system can be performed. Therefore, it is effective in improving the economic efficiency and expanding the use of such a waste heat utilization system.

In the system of the present invention, the heat storage is a large amount of latent heat due to the phase change of the heat storage material, so that the heat storage tank can be reduced in size and weight, and the operating and equipment costs of the system can be reduced. It is reduced.

The invention according to claims 2 and 3 specifically shows a refrigerant, a heat storage material, and the like, and the above-mentioned effects can be similarly achieved.

Further, by operating the above adsorption type refrigeration system by the method according to the third aspect, the heat storage operation and the utilization operation in the system can be facilitated. In particular, when the cold heat is taken out, the refrigerator is generated together with the heat storage component. , It is possible to easily and efficiently supply an extremely large amount of cold heat to the user side. Further, since such utilization operation can be performed, in the system of the present invention, if the heat is stored at night, the heat storage can cover approximately half of the load in the daytime, and therefore, the capacity of the installed adsorbent chiller is the conventional capacity. It may be 1/2, which is also effective for reducing equipment costs.

As described above, the adsorption refrigeration system according to the present invention uses a heat storage material that changes phase at a low temperature, and thus is suitable for industrial low temperature applications such as food processing and refrigeration.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of an adsorption refrigeration system having a heat storage function according to the present invention.

[Explanation of symbols]

 (1) Adsorption type refrigerator (2) Heat storage tank (3) Heat exchanger (4) User side equipment (5) Adsorption tower (13) Evaporator (15) Heat medium liquid circulation pipe (19) Three-way valve

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Satoshi Ibe 4-1-2, Hirano-cho, Chuo-ku, Osaka-shi Inside Osaka Gas Co., Ltd. Inside Nishiyodo Air Conditioner Co., Ltd. (72) Inventor Masao Matsushita 1-5-10 Himezato, Nishiyodogawa-ku, Osaka City Inside Nishiyodo Air Conditioner Co., Ltd. Inside Nishi-Yodo Air Conditioner Co., Ltd. (72) Inventor Akiyoshi Sakai 1-5-10 Himezato, Nishiyodogawa-ku, Osaka City Inside Nishi-Yodo Air Conditioner Co., Ltd. (56) References JP-A-4-236076 (JP, A) JP-A-63-194165 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F25B 17/08

Claims (4)

(57) [Claims] 1. A process in which a plurality of adsorption towers filled with an adsorbent are used and connected to a condenser and an evaporator so that a refrigerant can circulate in each of the adsorption towers, and at least one of the adsorption towers is different from the others. Thus, the adsorption, the evaporator of the adsorption refrigerator that enabled the desorption process switching operation, and a heat storage tank filled with a substance having a higher freezing point than the refrigerant of the adsorption refrigerator as a heat storage material. An adsorption-type refrigeration system having a heat storage function, characterized in that the cooling medium is connected by a pipe through which a heat medium circulates, and a cold heat extraction section is provided in parallel in the middle of the circulation pipe via a three-way valve. 2. The adsorption type refrigeration system having a heat storage function according to claim 1, wherein activated carbon is used as an adsorbent, alcohol is used as a refrigerant, and water is used as a heat storage material. 3. The adsorptive refrigeration system having a heat storage function according to claim 1, wherein silica gel is used as an adsorbent, water is used as a refrigerant, and clathrate is used as a heat storage material. A heat storage material is circulated by circulating cold heat output from an evaporator to a heat storage tank via a heat medium using the adsorption refrigeration system having a heat storage function according to claim 1, 2 or 3. The solidified heat is measured, and then the three-way valve is switched, and the cold heat output from the evaporator and the stored cold heat, or only the stored cold heat, is transferred to the use side from the cold heat extraction unit via the heat medium. Driving method characterized by taking out.