JP3307744B2 - Ice heat storage system using absorption heat pump. - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ice heat storage system suitable for a heat storage type air-conditioning system using midnight power or the like, in particular, an absorption heat pump using water as a refrigerant, and the use of ice by utilizing latent heat of vaporization of water. The present invention relates to an ice heat storage system that stores cold heat.

[0002]

2. Description of the Related Art In recent years, the maximum power consumption in summer has increased due to a rapid increase in power used for cooling and the like. On the other hand, as typified by energy saving in a power consuming industry, the industrial industry is trying to reduce the dependence on electric energy, and accordingly, the annual average load factor for power generation equipment tends to decrease. For this reason, a technique for efficiently storing nighttime power energy and using it for cooling or the like has become extremely useful. Further, since a conventional ice heat storage device using a chlorofluorocarbon-based refrigerant is not preferable from the viewpoint of protection of the ozone layer, an ice heat storage system has been attracting attention as a device capable of storing cold heat without using a chlorofluorocarbon-based refrigerant.

The applicant of the present invention has previously proposed an ice heat storage system of this type described in Japanese Patent Application Laid-Open No. 3-912623. In this device, a heat storage body that can have a large water-steam interface area is formed using a water-absorbing polymer gel, and the inside of an ice heat storage tank provided with a plurality of the heat storage bodies is evacuated by a vacuum exhaust device. In addition, a large amount of water in the gel is efficiently frozen with the release of latent heat of evaporation.

On the other hand, as another air conditioning system which does not use a CFC-based refrigerant, a system using an absorption heat pump system is known. This air conditioning system comprises, for example, an evaporator, an absorber, a generator, a condenser and the like using lithium bromide (LiBr) as an absorbent and water as a refrigerant, and discharges latent heat of evaporation of water in the evaporator. To cool the cold water.

[0005]

However, even in such a steam exhaust type ice heat storage system, it is necessary to provide a dedicated exhaust means for discharging the steam to the outside while reducing the pressure in the heat storage tank to a considerably low pressure. There is. In addition, a large amount of water is discharged to the outside of the heat storage tank as water vapor during heat storage, and the amount of water in the heat storage tank is reduced. Therefore, a dedicated means for condensing the discharged water vapor and collecting it again in the heat storage tank is required. .

[0006] Further, in an air conditioning system using an absorption heat pump system, since it is not possible to store cold heat, it is difficult to avoid an increase in the size of the system in order to satisfy the required cooling output. From the point of view, practical use of a combination with a cold heat storage device is desirable, but when using an ice heat storage system of a steam exhaust type and an air conditioning system using an absorption heat pump system, there are a plurality of means having the same function. Therefore, there is a problem to be improved from the viewpoint of simplification of the configuration and cost reduction.

[0007] Therefore, the present invention is capable of efficiently exhausting and recovering steam utilizing a part of the means provided in the absorption heat pump system, and has a simple configuration capable of reducing the size of the air conditioning system. It is an object to provide a low-cost ice heat storage system.

[0008]

In order to achieve the above object, an ice heat storage system using an absorption heat pump according to the first aspect of the present invention evaporates internal water by depressurization and releases external heat by evaporating latent heat. An evaporator that cools the low-temperature heat medium from the evaporator, an absorber connected to the evaporator to absorb the water vapor from the evaporator into the absorbing liquid therein, and a circulating device for the absorbing liquid. A generator for generating steam from the absorbing liquid introduced therein by heat exchange with a high-temperature heat medium from the outside, a condenser connected to the generator to cool and condense the steam from the generator, and An ice heat storage tank for evaporating the water inside by absorbing and generating ice by releasing the latent heat of evaporation to store cold heat, a first exhaust state for depressurizing the evaporator and the absorber, and a second method for depressurizing the ice heat storage tank. in the second exhaust state And exhaust means for moving, by cold energy stored in the heat the ice thermal storage tank and a, and heat exchanger means for cooling the low-temperature heat medium from the outside.

According to the present invention, the exhaust means operates in the first and second exhaust states and depressurizes the absorber, and operates in the second exhaust state to decompress the heat storage tank. A second exhaust pump that guides water vapor from the heat storage tank to the absorber, and a shut-off valve that operates in the second exhaust state and shuts off the connection between the evaporator and the absorber. The invention according to claim 2 , wherein the first exhaust means operates in the first exhaust state, and supplies water condensed in the condenser to the evaporator, and the second exhaust state. And a second water supply means for supplying water condensed in the condenser to the heat storage tank.

[0010]

The exhaust means reduces the pressure in the evaporator and the absorber.
When operated in the exhaust state, the water inside the evaporator evaporates, and the low-temperature heat medium from the outside is cooled by releasing the latent heat of evaporation. On the other hand, when the evacuation means operates in the second evacuation state in which the pressure in the ice heat storage tank is reduced, water in the ice heat storage tank evaporates and ice is produced by the release of the latent heat of evaporation, thereby storing cold heat. The cold stored in the ice storage tank is used to cool the low-temperature heat medium by the heat exchange means. Water vapor discharged from the evaporator in the first exhaust state or water vapor exhausted from the heat storage tank in the second exhaust state is absorbed by the absorbing liquid in the absorber, and the absorbing liquid diluted by this absorption is discharged in the generator. Heat is generated by heat exchange with an external high-temperature heat medium to generate steam, which is regenerated to a predetermined concentration. Further, the steam generated by the generator is cooled by the condenser, condensed, and returns to water.

As described above, by appropriately switching the exhaust state of the exhaust means and the operation state of the heat exchange means, the cooling of the low-temperature heat medium using water as the refrigerant and the cold heat storage are arbitrarily and selectively performed. . In addition, in either the cooling of the low-temperature heat medium or the cold heat storage, the absorption liquid diluted by absorption is regenerated through the generator, so that the cold heat can be efficiently stored and the entire system can be downsized.

According to the first aspect of the present invention, the first
When the first exhaust pump is operated in an exhaust state, that is, in a state where the shut-off valve is opened and the evaporator and the absorber are connected, the evaporator and the absorber are depressurized, and water in the evaporator evaporates. The low-temperature heat medium from the outside is cooled by the release of the latent heat of evaporation. Further, when the first and second exhaust pumps operate in the second exhaust state, that is, in a state in which the shutoff valve is closed and the connection between the evaporator and the absorber is shut off, water in the ice heat storage tank evaporates. Then, ice is produced by the release of the latent heat of evaporation, and cold heat is stored.

Therefore, when performing cold heat storage,
The connection between the evaporator and the absorber is cut off to reduce the load on the first exhaust pump, and the load on the second exhaust pump is greatly reduced by the exhaust of the absorber by the first exhaust pump, resulting in efficient heat storage. Can be performed. Furthermore, in the second aspect of the invention, in the first exhaust state, water condensed in the condenser is sent to the evaporator by the first water sending means.
In the second exhaust state, water condensed in the condenser is sent to the heat storage tank by the second water sending means. Therefore, an appropriate amount of make-up water can be supplied to the evaporator or the ice heat storage tank in accordance with the operation state of the system.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below with reference to the drawings. FIGS. 1 and 2 are views showing an embodiment of an ice heat storage system using an absorption heat pump according to the first or second aspect of the present invention. First, the configuration will be described.

The ice heat storage system of this embodiment performs cold heat storage (ice heat storage) using ice by using a heat cycle of a heat pump system serving as an absorption refrigeration apparatus, and is a main element constituting the heat cycle. It has an evaporator 1, an absorber 2, a generator 3 and a condenser 4. Evaporator 1
Has a heat transfer tube 1a for storing water as a refrigerant therein and for passing cold water (low-temperature refrigerant) from outside above the water surface. The water in the evaporator 1 is sent to the water discharge pipe 12 by the refrigerant liquid pump 11, and is dropped or jetted from the nozzle portion toward the heat transfer pipe 1a. Evaporator 1
The inside is evacuated and decompressed to a predetermined pressure (for example, 6 to 8 mmHg) together with the absorber 2 by the vacuum pump 21, and the pressure is used to evaporate water as a refrigerant. Then, the cold water from the outside which is passed through the heat transfer tube 1a is further cooled by releasing the latent heat of evaporation. The water passed through the heat transfer tube 1a is used, for example, for a cooling device. The absorber 2 contains a predetermined absorbing liquid L, for example, lithium bromide (LiBr), and sends the water vapor from the evaporator 1 to the evaporator 1 through the on-off valve 15 so as to absorb the water into the absorbing liquid L. It is connected. Absorbent liquid L, which absorbs water vapor in absorber 2 and is diluted, is supplied to generator 3 by absorbent pump 22. The generator 3 is a heat transfer tube 3 through which high-temperature steam (a high-temperature heat medium: high-temperature hot water or the like may be passed) from the outside.
a, and heat exchange is performed between the absorbing liquid L introduced from the absorber 2 through the heat transfer tube 3a and the high-temperature heat medium to heat the absorbing liquid L to generate steam. The absorbing solution L heated in the generator 3 and restored to a predetermined concentration is returned into the absorber 2 via the heat exchanger 23 and the liquid return pipe 24. Also,
The absorption liquid L returning from the generator 3 to the absorber 2 and the absorption liquid L sent from the absorber 2 to the generator 3 exchange heat in the heat exchanger 23, and the temperature of the absorption liquid L returning to the absorber 2 decreases. It is supposed to. In this embodiment, since the temperature of the high-temperature medium is considerably high, the absorbing liquid L returned from the generator 3 to the absorber 2 is further cooled by the heat transfer tube 2a through which cooling water passes. The condenser 4 has a heat transfer tube 4a through which cooling water passes.
And connected to the generator 3. The condenser 4 cools and condenses the steam from the generator 3 by the heat transfer tube 4a. Water accumulated in the condenser 4 due to the condensation passes through the first water supply passage 25 (first water supply means) having the on-off valve 25a in the first exhaust state.
In the second exhaust state, the water is sent to a water discharge pipe 35 provided in the ice heat storage tank 5 through a second water supply passage 26 (second water supply means) having an on-off valve 26a.

Numeral 5 denotes an ice heat storage tank, in which a gel-like water-absorbing polymer material containing water (Water Absolute) is provided.
rbable Polymer) is stored.
In addition, a predetermined amount of water is stored. The water-absorbing polymer is used extensively in disposable diapers and sanitary goods,
It absorbs water several times to several tens times or several hundred times its own weight depending on the material, and has the property of becoming a gel. The water in the gel is free water having a melting point of 0 ° C., which is almost the same as ordinary water, and it can be considered that the evaporation, condensation and solidification of the water occur under conditions close to ordinary water. The ice heat storage tank 5 is operated at a predetermined pressure (for example,
It is evacuated and decompressed to 4.5 mmHg) to evaporate the water inside and generate ice by releasing the latent heat of evaporation to store cold heat. The cold stored in the ice storage tank 5 is sent to the heat exchanger 34 by the cold water pump 33 via water, and exchanges heat with cold water (low-temperature heat medium) from outside.
That is, cold water similar to the cold water cooled by the evaporator 1 can also be cooled by the heat exchanger 34. Also,
An absorption type heat pump using water as a refrigerant has a limit of obtaining cold water of 5 ° C to 7 ° C.
Cold water with a low water temperature of about ° C can be obtained.

The on-off valve 15, the vacuum pump 21 and the vacuum primary pump 32 are used to reduce the pressure in the evaporator 1 and the absorber 2
And the second exhaust state for depressurizing the ice heat storage tank 5 constitutes an exhaust means 6 that operates in any one of the exhaust states. The cold water pump 33 and the heat exchanger 34 are used for storing ice heat. The heat exchange means 7 for cooling the cold water (low-temperature heat medium) from the outside by the cold stored in the tank 5. The vacuum pump 21 of the exhaust means 6 is a first exhaust pump that operates in the first and second exhaust states to decompress the absorber 2, and the vacuum primary pump 32 operates in the second exhaust state to store ice heat. A second exhaust pump that depressurizes the tank 5 and guides water vapor from the ice heat storage tank 5 to the absorber 2;
Reference numeral 15 denotes a shutoff valve which closes the valve in the second exhaust state and cuts off the connection between the evaporator 1 and the absorber 2.

In this embodiment, water is externally supplied to the ice heat storage tank 1 every predetermined heat storage time by a supply means (not shown). The cold water in the ice heat storage tank 1 is
When the chilled water pump 33 operates with the valves 6 and 17 opened, the chilled water is stored in the storage tank 18. Reference numeral 19 denotes a supply valve for supplying water to the storage tank 18. Next, the operation will be described.

First, when this system is operated as an absorption refrigeration system, the exhaust means 6 operates in the first exhaust state until the evaporator 1 and the absorber 2 are reduced to a certain reduced pressure state. That is, the vacuum pump 21 operates with the on-off valve 15 opened and the evaporator 1 and the absorber 2 connected.
At this time, the water in the evaporator 1 evaporates, and the cold water that is externally passed through the heat transfer tube 1a is cooled by the release of the latent heat of evaporation. Therefore, daytime cooling or the like using this cold water becomes possible.

On the other hand, when performing ice heat storage at night or the like when the operation of the refrigerating apparatus is stopped, the exhaust means 6 operates in the second exhaust state in which the pressure in the ice heat storage tank 5 is reduced. That is, while the on-off valve 15 is closed and the connection between the evaporator 1 and the absorber 2 is cut off, the vacuum pump 21
Operates, and the primary vacuum pump 32 operates. At this time, the water in the ice heat storage tank 5 evaporates, and the latent heat of evaporation is released, so that ice is produced in the gel contained in the heat storage body 31 in the ice heat storage tank 5, thereby performing cold heat storage. At this time, since the connection between the evaporator 1 and the absorber 2 is cut off by the on-off valve 15, the load on the first vacuum pump 21 is reduced, and the pressure in the absorber 2 is reduced. The load on the pump 32 is greatly reduced. That is, since the pressure difference before and after the vacuum primary pump 32 is about several mmHg, it is higher when the vacuum primary pump 32 is evacuated into the atmosphere (760 mmHg) or into a dedicated condenser (for example, about 35 mmHg). No exhaust capacity is required, and sufficient exhaust is possible. Therefore, efficient heat storage operation becomes possible.

Water vapor discharged from the evaporator 1 in the first exhaust state or water vapor exhausted from the ice heat storage tank 5 in the second exhaust state is absorbed by the absorbing liquid L in the absorber 2 and diluted by the absorption. The absorbed liquid L is heated by heat exchange with steam (high-temperature heat medium) from the outside in the generator 3 to generate steam, and is regenerated to a predetermined concentration. The water vapor generated by the generator 3 is cooled by the condenser 4 and condensed, and returns to water.

As described above, the cold stored in the ice storage tank 5 using the nighttime electric power or the like is used to cool external cold water in the same manner as during the operation of the refrigeration apparatus described above. That is, the chilled water pump 33 is operated with the valves 16 and 17 opened, and the water in the ice heat storage tank 1 and the storage tank 18 is circulated through the heat exchanger 34, and the chilled water ( (For example, 15 ° C.). Therefore, the vacuum pump 21, the motor drive circuit 22, and the primary vacuum pump 32 are operated by using the nighttime electric power or the like, and the generator 3 is supplied with appropriate hot waste water or steam or hot water heated to high temperature using daytime solar heat. , It is possible to perform cold heat storage at low cost, and to consume it, only the cold water pump 33 needs to be driven.

In the first exhaust state, the on-off valve
The water condensed in the condenser 4 by opening 25a is sent to the evaporator 1 through the first water supply passage 25. In the second exhaust state, the water condensed in the condenser 4 by opening the on-off valve 26a. Is supplied to the ice heat storage tank 5 through the second water supply passage 26, so that an appropriate amount of makeup water can be supplied to the evaporator 1 and the ice heat storage tank 5 with a simple configuration in accordance with the operating state of the system.

As described above, in the present embodiment, the cooling of the cold water and the cold heat storage are arbitrarily and selectively performed by appropriately switching the exhaust state of the exhaust means 6 and the operation state of the heat exchange means 7. Moreover, in any case, the absorption liquid L diluted by absorption is regenerated through the generator 3, and the absorber 2, the generator 3, and the condenser 4 and their associated components are shared, so that the cooling and heating can be performed efficiently. Can store heat,
The whole system is downsized. That is, a simple and low-cost ice heat storage system having a configuration capable of efficiently exhausting and recovering steam by utilizing a part of the means provided in the absorption heat pump system is provided. Moreover, since the air conditioning system uses an absorption heat pump system and can store cold heat, the absorption heat pump system can be downsized to about half the conventional size by utilizing the cold heat stored at night or the like during cooling. Thus, the size and cost of the entire air conditioning system can be reduced.

In the above-described embodiment, the absorption type heat pump system is described only as a refrigerator used for cooling or the like as in the case of the ice heat storage tank. However, it goes without saying that the absorption type heat pump system can also be used as a heat pump. In other words, the present invention can be used not only for cooling an external low-temperature heat medium (cold water) by an evaporator for cooling, but also for increasing the temperature of the external heat medium by the heat of condensation in the condenser. The vacuum primary pump 32 is operated with the on-off valve 15 opened to cool the cold water using the evaporator 1 and the ice heat storage tank 5.
Needless to say, it is possible to simultaneously perform the cold heat storage using the heat. Further, the ice heat storage tank 5 does not have to have the heat storage body 31 and may have another type of heat storage means.

[0026]

Operating state of the exhaust state and the heat exchange means of the exhaust means according to the present invention by switching the appropriate water can be carried out arbitrarily selectively cooling and cold thermal storage of cold heat medium to the refrigerant, a low temperature heat Regardless of whether the medium is cooled or stored in the cold storage, the absorption liquid diluted by absorption is regenerated through the generator so that the cold storage can be efficiently performed and the whole system can be downsized. As a result, a part of the means provided in the absorption heat pump system can be used to efficiently exhaust and recover the steam, and the simple and low-cost ice heat storage having a configuration capable of downsizing the air conditioning system. A system can be provided.

According to the first aspect of the present invention, it is possible to switch between a heat cycle including the evaporator and a heat cycle not including the evaporator by opening and closing the shut-off valve. The connection can be cut off to reduce the load on the first exhaust pump, and the load in the second exhaust pump can be significantly reduced by exhaustion in the absorber, so that efficient heat storage can be performed.

According to the second aspect of the present invention, the water condensed in the condenser is sent to the evaporator in the first exhaust state, and the water condensed in the condenser in the second exhaust state. Is supplied to the heat storage tank, so that an appropriate amount of makeup water corresponding to the operation state of the system can be supplied to the evaporator or the ice heat storage tank with a simple configuration.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of an ice heat storage system using an absorption heat pump according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Evaporator 1a, 2a, 3a, 4a Heat transfer tube 2 Absorber 3 Generator 4 Condenser 5 Ice heat storage tank 6 Exhaust means 7 Heat exchange means 11 Refrigerant liquid pump 12 Water discharge pipe 15 Opening / closing valve (shutoff valve) 18 Storage tank 21 Vacuum pump (first exhaust pump) 22 Absorbent pump 23 Heat exchanger 25 First water supply passage (first water supply means) 26 Second water supply passage (second water supply means) 31 Heat storage body 32 Vacuum primary pump (second exhaust pump) ) 33 Chilled water pump 34 Heat exchanger

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Satoshi Hongo 1-35-8 Nihonbashi Kakigara-cho, Chuo-ku, Tokyo Sanken Equipment Co., Ltd. (56) References JP-A-5-332648 (JP, A JP-A-5-248724 (JP, A) JP-A-54-102647 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F24F 5/00

Claims (2)

(57) [Claims] 1. An evaporator for evaporating water inside by depressurization and cooling a low-temperature heat medium from outside by releasing latent heat of evaporation, and an evaporator for absorbing water vapor from the evaporator into an absorbing liquid inside. A generator provided to circulate the absorbing liquid between the connected absorber and the absorber, and generating steam from the absorbing liquid introduced into the inside by heat exchange with an external high-temperature heat medium; and A condenser connected to the generator so as to cool and condense the water vapor from the water, an ice heat storage tank that evaporates the internal water by decompression and absorption, generates ice by releasing the latent heat of evaporation, and stores cold heat, The exhaust system operates in a first exhaust state in which the evaporator and the absorber are depressurized and a second exhaust state in which the ice heat storage tank is depressurized.
Air means operating in the first and second exhaust states and absorbing
A first exhaust pump for depressurizing the vessel, and in the second exhaust state
Activates and decompresses the heat storage tank and water vapor from the heat storage tank
Operating in a second exhaust state with a second exhaust pump that guides air to the absorber.
A shut-off valve that operates to cut off the connection between the evaporator and the absorber, and heat exchange means for cooling the external low-temperature heat medium by the cold stored in the ice heat storage tank. Ice heat storage system using a heat pump. 2. A first water supply means which operates in the first exhaust state and supplies water condensed in the condenser to the evaporator; and operates in the second exhaust state and supplies the water inside the condenser. The ice heat storage system using the absorption heat pump according to claim 1, further comprising: a second water supply unit configured to supply water condensed in (1) to the heat storage tank.