JP2001330273A - Cooling system using solid absorbent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a cooling system for utilizing a solar heat to be simple and practical and besides excellent in performance. SOLUTION: By effecting a flow of hot air heated by a solar heat to a packed bed where air filled with solid absorbent particles, such as granular silica gel, can flow, solid absorbent particles are dehumidified and regenerated, and moisture in air is absorbed in an absorbent to reduce humidity in air. Since an absorption heat is generated when humidity is removed, an air temperature is increased. In reduction of the air temperature by supplying outside air having a low temperature at midnight, to a crushed stone heat storage device, the temperature of crushed stones is reduced. Through the feed of air with decreased humidity to the crushed stones of the decreased temperature, temperature in air is lowered. By humidifying low humidity air, a cooling effect is produced. In this system, since, after the solid absorbent is dehumidified and regenerated, the solid absorbent becomes a high temperature approximately equal to the temperature of hot air, dehumidification is impracticable unless temperature is decreased. As a result, the system cools the solid absorbent through the heat exchanger in a manner that a moisture content in air is not adsorbed when the solid absorbent is cooled by air.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in the performance of a dehumidification type cooling system (desiccant type cooling system) using a particulate solid hygroscopic agent, which is a simple cooling system utilizing solar heat or low-temperature waste heat.

[0002]

2. Description of the Related Art In a conventional heating and hot water supply system utilizing solar heat for a house, a hot air collecting system is increasingly used from the viewpoint of maintenance, easiness of handling, and durability. In this system, solar energy is used only for hot water supply in summer, and heat collection for heating is not required. Therefore, the utilization rate of equipment is poor, and thus there is a problem from the viewpoint of economic efficiency of the system. In summer, various studies have been made to utilize the heat collection for heating for cooling. However, conventionally, as a cooling system using solar heat, although an absorption type cooling system using an aqueous solution of lithium bromide has been experimentally used, it is mainly used, and it is difficult to apply this system to a hot air collecting system. This absorption type air conditioner using an aqueous solution of lithium bromide is a method conventionally used as an air-conditioner using an oil or gas boiler, and boils or condenses an aqueous solution of lithium bromide in a vacuum sealed container. It operates and requires advanced technology in terms of manufacturing technology, and it is difficult to utilize solar heat unless a high-temperature water collecting system of 100 ° C. or higher is used. Therefore, it was not economically justified in terms of cost and was only used experimentally.

[0003] On the other hand, a desiccant type cooling system using a moisture absorbent that absorbs moisture in the air is said to be capable of cooling with a relatively simple device, and is more suitable as a cooling system utilizing natural energy such as solar energy. Research has been done as. Conventionally, a desiccant cooling system experimentally made is made of a disc-shaped moisture-absorbing rotor by wrapping cardboard paper carrying a moisture-absorbing agent around a shaft.
The rotor is divided in half by diameter, and hot air is flown to one side to perform a regenerating process of the hygroscopic agent, and normal temperature air is flown to the other side to perform a dehumidifying process of removing humidity in the air. In this method, the rotor is rotated at a speed of about one rotation per minute, and the regeneration process and the dehumidification process are alternately performed.

[0004]

In the above desiccant cooling method, the regeneration step of the dehumidifier and the dehumidification cooling step are performed at the same time, so that cooling can be performed when hot air for regeneration is obtained, that is, solar heat is collected. Only enthusiastic. In order to be able to perform cooling when it is not collecting heat, a heat storage device is required, which is not attractive in terms of cost.

Outside air is generally used to reduce the temperature of air whose temperature has risen by reducing the humidity in the air through a dehumidifying agent. However, lowering the cooling temperature as much as possible increases the effect of desiccant cooling. Most important to. Therefore, in the case of cooling by outside air, there is a problem that the cooling effect is inferior when the cooling needs to be the highest when the outside air temperature is high.

[0006] The problem of energy and the problem of reducing carbon dioxide emissions have become global political issues, and among technologies for reducing energy consumption for consumer use, it is relatively easy to use solar energy for hot water supply and heating. It has been a long time since its spread promotion policy has been implemented in Japan. Use of solar energy for hot water supply
Although it is already quite common in Japan, everyone has experienced that solar radiation from windows can provide a sufficient heating effect, and it should be easier to use than hot water supply. However, the use of solar heating systems beyond solar radiation through windows is very rare. However, the number of solar houses equipped with a solar heating and hot air system for home heating and hot water supply has been small for more than 20 years, but they have been constructed and are almost technically established. It is in a situation where it can be expected.

[0007] However, since the heating system can be used only in winter, the disadvantage in terms of economy in that respect is also a factor that hinders its spread. Therefore, there is a demand for the development of a simple solar cooling system that can perform cooling by adding a few elements to the heating system.

[0008]

FIG. 1 is a block diagram of a heating / hot water supply system utilizing the solar heat for a house of the above-mentioned hot air collecting type using a hot air collecting system. 1 is a heat collecting roof for heating the air with solar heat to obtain warm air. By operating a fan 4, warm air is taken out from an opening 2 to a triangular duct indicated by 3, and a hot water supply heat of 5 The heat is guided to the crushed stone heat storage device 7 through the heat exchanger and the heat collection duct 6. In addition, warm air is blown into the room from the ceiling outlet 10 through the distribution duct by the air-conditioning fan 8, thereby heating the room. When the hot air passes through the crushed stone heat storage device 7, it applies heat to the crushed stone 7 a to become room temperature air, and enters the heat collecting roof 1 via the return duct 11 to make a full round. The heat stored in the heat storage device 7 is controlled by the air conditioning fan 8 when there is no solar radiation.
The indoor air returns from the slab 12 and is heated through the crushed stones, and becomes warm air, which is blown out from the 10 ceiling outlets and used for heating.

In such a hot air collecting solar house, the hot air taken out of the heat collecting roof in the summer passes through the hot water supply heat exchanger 5 to heat the hot water, and then the heat collecting damper 13 is used.
Is discharged outside through the exhaust port 14 and is not used. FIG. 2 shows the principle of cooling using the hot air that is wasted in the summer. (A) shows the process of regenerating the desiccant with the warm air of the solar heat, and heats and dehumidifies the desiccant when the warm air passes through the desiccant particles 16 placed in the heat insulating box 15. Are discharged from the exhaust port 17.

FIG. 2 (b) shows a cooling process, in which indoor air is dehumidified by passing through the absorbent particles 16, and the air whose temperature has risen due to heat of adsorption is cooled by the crushed stone heat storage device 7, and the air is further cooled. The air whose temperature has been reduced by the latent heat of vaporization after being humidified by the humidifier 20 is blown into the room through the blowout port 19. FIG.
FIG. 2B shows the cooling cycle of FIG. 2B using a psychrometric chart, where the horizontal axis represents the air temperature, the vertical axis represents the absolute humidity of the air,
The downward-sloping line of about 45 ° is a line indicating isenthalpy of air. The point A in FIG.
The relative humidity is a point of 60%, and the process of dehumidifying the air in this state through the desiccant is an isenthalpy change. The air at the outlet of the desiccant is in the state of point B in FIG.
° C, relative humidity 8% and enters crushed stone. Assuming that the crushed stone cools down to 30 ° C. without changing the absolute humidity, FIG.
The temperature reaches 30 ° C. and a relative humidity of 19% and enters the humidifier. When the humidification process is humidified to a relative humidity of 90% by an isenthalpy change, the humidifier outlet state becomes the D point 17 ° C. in FIG.
The absolute humidity is also lower than the point A in FIG. 3 of the indoor air condition, and it can be seen that good cooling is performed.

What is important in this cycle diagram is to cool the sky, which has risen in low humidity to a temperature of about 30 ° C., through a desiccant, and to cool it with outside air using a heat exchanger. Often it cannot be cooled down to 30 ° C. Good cooling is possible by pre-cooling the crushed stones in the open air at midnight.

[0012] Further, when shifting from the regeneration step of FIG. 2 (a) to the cooling step of FIG. 2 (b), if the moisture absorbent remains at the high temperature of the regeneration step, moisture is not absorbed. As a means for solving this problem, a main point of the present invention is to solve the problem by inserting a cooling plate for cooling the moisture absorbent by air in the moisture absorbent packed layer.

【Example】

FIG. 4 is a system configuration diagram of one embodiment of the present invention. Symbols 1 to 13 are the same as those in FIG. 1, reference numeral 21 denotes hygroscopic particles, and reference numeral 22 denotes a cooling plate for cooling the hygroscopic agent by air. When the outside air temperature drops at midnight in summer, for example, from midnight at midnight to 5:00 in the morning, the heat collection fan 4 is operated under timer control to take in outside air from the outside air intake 23 and to the crushed stone heat storage device through the heat collector. Send and let the crushed stone cool.
The air that has come out of the crushed stone is discharged to the outside from a wind-type exhaust damper 24.

When the solar radiation hits the heat collecting roof and the temperature of the heat collecting plate becomes 1
When the temperature reaches 00 ° C. or higher is detected by a heat collecting plate temperature sensor (not shown), the heat collecting fan 4 is operated. In summer, the heat collecting damper 28 is tilted to the right, the hot air from the heat collecting roof does not go to the heat storage device, the damper 29 opens, and a part of the heat collecting hot air heats the hot water supply heat exchanger 27. 32 entrances 3
It returns to the square duct and is sucked into the heat collecting roof again. In the hot water supply heat exchanger 27, water is circulated from the hot water storage tank 33 by the pump 34, turned into hot water in the heat exchanger, returned to the upper part of the hot water storage tank, and stored from the upper part of the hot water storage tank.

The other portion of the collected hot air is discharged from an exhaust port 30 through a damper 29, for example, a spherical silica gel layer 21 which is a moisture absorbent. As the hot air passes through the silica gel layer, moisture adsorbed on the silica gel is desorbed and regenerated. There are two silica gel tanks,
When the lower part of the silica gel layer is detached, the damper 29 is closed, and the damper 29 of the other second silica gel tank is opened to perform regeneration.

A fan (not shown in FIG. 4) blows air to the cooling plate 22 of the silica gel tank where regeneration has been completed, thereby cooling the silica gel. FIG. 5 shows a cross section of the silica gel tank, and (a) shows the same cross section as FIG. 3-5
In the spherical silica gel particles 21 having a diameter of 25 mm, cooling plates having a honeycomb structure in which aluminum thin plates indicated by 22 are bonded in a cardboard shape are arranged at intervals of 20 to 30 mm in the air flow direction. (B) shows a cross section taken along the line BB shown in (a), and the air flows through the gap of the aluminum cardboard cooling plate 22 by operating the cooling fan 39 to cool the silica gel by heat conduction.

In FIG. 5 (a), after the temperature of the silica gel is cooled to about 40 to 30 ° C. by ventilation to the aluminum cooling plate, the damper 37 is opened, the fan 35 is operated, and the room air is discharged While being sucked and flowing through the silica gel packed bed from the bottom to the top, it is absorbed by moisture in the air and becomes dry air and enters the return duct 11 shown in FIG. The dry air that has entered the return duct is further sucked by the air conditioning fan 8 and cooled through the crushed stone heat storage device 7 that is cooled by the outside air at midnight. The temperature of the air-conditioning fan 8 is lowered by being humidified by the humidifier 20, and the air is blown out from the ceiling outlet 10 into the room through the distribution duct 9 to be cooled.

In FIG. 5 (a), the aluminum cardboard cooling plate 22 extends slightly above the silica gel packed bed. When the cooling is continuously performed by the cooling fan 39, the air that has been dehumidified and has exited the silica gel layer can be further cooled by the cooling plate. The effect of continuously flowing the cooling air through the cooling plate during the dehumidifying operation will be described with reference to the diagram of FIG. 3. The process of dehumidifying the indoor air condition A with the silica gel layer is an isenthalpy process of AB, The dehumidification process while cooling air is flowing through the cooling plate changes from A to B ', and is further cooled and humidified with crushed stone, and at the outlet D' point, temperature 15.
At 6 ° C. and 90% humidity, it can be seen that the cooling effect is greater than when no air is passed through the cooling plate.

Considering the case where the humidification step is started without cooling with crushed stones after the dehumidification step, if the cooling plate 22 is not operated, dehumidification by humidification changes from A to B in FIG. No cooling effect is obtained at all. However, when the cooling plate 22 is operating, the temperature becomes B 'after dehumidification as described above, and when humidified from B', the point E and the temperature are 18.3.
It was found that the temperature was 90 ° C. and the humidity was 90%, and a considerable cooling effect could be obtained without cooling by crushed stone. As described above, the effect of installing the cooling plate in the silica gel layer not only cools the silica gel after the regeneration step but also improves the cooling performance. The effect that the cooling plate 22 of FIG. 5A extends from the silica gel layer has the same effect as the cooling by the crushed stone even when there is no cooling by the crushed stone. Needless to say, it is inferior to cooling by crushed stone cooled by outside air at midnight.

[0020]

According to the present invention, cooling and cooling can be performed by using the hot air thrown away in the summer by additionally installing a silica gel tank, a damper, a fan, etc. while keeping the conventional system and elements of the hot air collecting solar house. Although various studies have been made on cooling using solar energy, hope has been almost cut off in terms of economy except for operating a normal air conditioner by solar cell power generation. The method of the present invention contributes to promoting the use of solar heat for heating,
It also gives hope to new research on solar cooling.

[Brief description of the drawings]

FIG. 1 (a) is a configuration diagram of a conventional heating / hot water supply system utilizing solar heat utilizing a hot air collecting system.

FIG. 1B is a sectional view of a heat collecting roof.

FIG. 2 is a diagram illustrating the principle of cooling in a hot air collecting solar heat utilization system.

FIG. 2A is an explanatory view of a regeneration process of a dehumidifier.

FIG. 2B is an explanatory diagram of a cooling process.

FIG. 3 Desiccant cooling cycle on psychrometric chart

FIG. 4 shows a hot air type solar heating / cooling / heating system according to an embodiment of the present invention.
Hot water supply system configuration diagram

FIG. 5 (a) Longitudinal sectional view of a silica gel tank according to one embodiment of the present invention.

FIG. 5 (b) Cross-sectional view of a silica gel tank according to one embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heat collecting roof 2 Hot air outlet from heat collecting roof 3 Heat collecting triangle duct 4 Heat collecting fan 5 Hot water supply heat exchanger 6 Heat collecting duct 7 Crushed stone heat storage device 7a Crushed stone 8 Air conditioning fan 9 Air conditioning distribution duct 10 DESCRIPTION OF SYMBOLS 11 Return duct 12 Air-conditioning air return gusset 13 Heat collection damper 14 Summer exhaust duct 15 Hygroscopic tank 16 Hygroscopic particle 17 Regeneration hot air exhaust port 18 Indoor air intake port 19 Cooling air outlet port 20 Humidifier 21 Silica gel particle 22 Silica gel particle cooling Plate 23 Outside air intake 24 Wind pressure type exhaust damper 25 Intake switching damper 26 Hot water supply heating branch duct control damper 27 Hot water supply heat exchanger 28 Heat collection damper 29 Silica gel regeneration hot air control damper 30 Regeneration hot air exhaust outlet 31 Cooling air suction control damper 32 Return triangular duct 33 Hot water storage tank 34 Heat collection and circulation pump 3 5 Cooling fan 37 Cooling damper 38 Cooling air inlet 39 Cooling fan

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F24J 2/04 F

Claims (1)

[Claims] 1. A warm air generating system for dehumidifying and regenerating the solid moisture absorbent by flowing hot air through the packed bed of the particulate solid moisture absorbent and the solid moisture absorbent, and the solid moisture absorbent By blowing air through the agent-filled layer, adsorbing moisture in the air to the solid desiccant and reducing the humidity in the air, a system for cooling the air with the reduced humidity, After the humidity reduction, the cooling system using a solid adsorbent that obtains a cooling effect by evaporating latent heat of water by humidifying the cooled air, a crushed stone heat storage device that cools the air with the reduced humidity is installed, A cooling plate by an air flow for cooling the solid adsorbent is inserted into the solid adsorbent packed bed at intervals in parallel to the flow direction of the regenerated hot air, and the crushed stone of the crushed stone heat storage device is inserted. In advance, late at night A cooling system using a solid desiccant, which can be cooled by air.