AU708106B2

AU708106B2 - Method and apparatus for cooling fluid and dehumidifying and cooling gas

Info

Publication number: AU708106B2
Application number: AU75055/96A
Authority: AU
Inventors: Tsutomu Hirose; Yukito Kawakami; Toshimi Kuma
Original assignee: CHIEKO KUMA; Seibu Giken Co Ltd
Current assignee: KUMA CHIEKO; Seibu Giken Co Ltd
Priority date: 1995-11-07
Filing date: 1996-11-06
Publication date: 1999-07-29
Anticipated expiration: 2016-11-06
Also published as: KR100461934B1; KR19990067373A; CN100378425C; WO1997017586A1; CN1201516A; AU7505596A

Description

Method and Apparatus for Cooling Fluid and Dehuidifying and Cooling Gas Field of the Invention The present invention relates to a method and a device for refrigerating fluid by heat exchange between fluids such as between air and air or between liquid and gas, and, as an application of them, to a method and device for desiccative refrigeration of gas such as air.

Background of the Invention For refrigerating gas, such as air, or liquid, generally used has been a freezer which performs refrigeration by heat of vaporization of Freon gas (chlorofluoro hydrocarbons: a trademark of duPont, liquidized by compressing volatile refrigerant such as Freon gas using a compressor. In such a freezer, for emitting compression heat of Freon gas, used is a cooling tower which performs refrigeration by passing Freon gas in a spiral hose on which water is flowed downward and also by heat of vaporization of the water brought about by flowing air in the counter direction.

It is requested in general air conditioning to obtain air of comfortable temperature and humidity, and it is necessary to lower both temperature and humidity in processing outer air of high temperature and high humidity.

As Freon gas is compressed by a compressor in such air conditioning, energy consumption is large and also destruction of ozone layer in the air by Freon gas is a serious matter. Large energy is consumed in a cooling tower, too.

Summary of the Invention The present invention is to provide a method and a device for refrigeration of fluid such as gas, like air, and liquid by using a heat exchanger, and as an application of them, to continuously supply air of comfortable temperature and humidity or gas of low temperature and low humidity by desiccative refrigeration of gas such as air using little energy and without using Freon gas.

In the present invention, in order to refrigerate high temperature fluid B by sensible heat exchange between low temperature gas A and high temperature fluid B using a cross-flow type heat exchanger or other heat exchangers in which two kinds of fluids of different temperature do not directly contact with each other, the low temperature gas A is put in the saturated condition with volatile liquid vapor such as water vapor, and then in the condition in which a large amount of minute water or other volatile liquid drops are further added to it being uniformly dispersed, an air flow Aa in the condition in which a large amount of minute liquid drops float in the gas. This is sent into one flow passage of the heat exchanger and the high temperature fluid B is sent into the other flow passage to vaporize the minute liquid drops M in the gas Aa mentioned above by sensible heat of the fluid B via the heat exchanger and to refrigerate the gas Aa by the vaporization heat of the liquid drops, thus refrigerating the fluid B in high efficiency by heat exchange between this cooled gas flow Aa and the fluid B.

Brief Description of the Drawings Fig. 1 is an explanatory drawing and a partially enlarged drawing of it showing an example of the method and the device for fluid refrigeration of the present invention; Fig. 2 is a perspective view showing an example of a cross-flow type heat exchanger and a partially enlarged drawing of it; Fig. 3 is a sectional view showing another example of the method and the device for fluid refrigeration of the present invention; Fig. 4 is an explanatory drawing of still another example of the method and the device for fluid refrigeration of the present invention; Fig. 5 is a psychometric chart showing data of fluid refrigeration shown in Fig. 4; Fig. 6 is an explanatory drawing showing a contrasting example of the method and the device for fluid refrigeration; Fig. 7 is a psychometric chart showing data of fluid refrigeration shown in Fig. 6; Fig. 8 is an explanatory drawing showing still another example of the method and the device for fluid refrigeration of the present invention; Fig. 9 is a psychometric chart showing data of fluid refrigeration shown in Fig. 8; Fig. 10 is an explanatory drawing showing data of fluid refrigeration of the present invention using aqueous solution of methanol; Fig. 11 is a psychometric chart showing data of refrigeration using aqueous solution of methanol; Fig. 12 is an explanatory drawing showing still another example of the method and the device for fluid refrigeration of the present invention; Fig. 13 is a perspective view of a counter-flow type heat exchanger; Fig. 14 is a perspective view showing an example of a heat exchanger combining a counter-flow and a cross-flow; Fig. 15 is a perspective view showing another example of a cross-flow type heat exchanger; Fig. 16 is an explanatory drawing showing an example of the method and the device for desiccative refrigeration of gas of the present invention; Fig. 17 is an explanatory drawing showing another example of the method and the device for desiccative refrigeration of gas of the present invention; Fig. 18 is an explanatory drawing showing still another example of the method and the device for desiccative refrigeration of gas of the present invention; Fig. 19 is a vertical section of a device for refrigeration in a refrigerator according to the present invention applied for refrigerator; Fig. 20 is a perspective view of a device for refrigeration in a refrigerator according to the present invention, a portion being broken away for the purpose of illustration; and Fig. 21 is a vertical section of a device for refrigeration according to the present invention applied for refrigerator.

Detailed Description of the Preferred Embodiments In the invention according to Claim 1, volatile liquid mist is added to a gas flow A to its saturation to form a gas flow Aa in which a large amount of misty minute liquid drops M float. Said gas flow Aa is passed through one flow passage of a heat exchanger with multiple flow passages, and fluid B to be refrigerated is passed through the other flow passage of the heat exchanger so that sensible heat of the fluid B is given to the gas flow Aa while the gas flow Aa passes through one flow passage of the heat exchanger, to elevate the temperature of the gas flow Aa. As the saturation ratio of the gas phase part (for example relative humidity in the case that the volatile liquid is water) lowers, a large amount of minute liquid drops M floating in the gas flow Aa are vaporized, and the temperature of the gas flow Aa drops continuously by heat of vaporization of the liquid drops to continuously I) 3 refrigerate the fluid B. Thus a gas flow Aa, in which a large amount of minute liquid drops M float, is heated by sensible heat exchange to the fluid B in the passage of the heat exchanger and fluid B is refrigerated by vaporization of minute liquid drops M which takes away heat of vaporization and by tempreture lowering of the gas Aa.

Example 1 Flat sheets 1 and corrugated sheets 2 of 3.0 mm wave length and 1.6 mm wave height, both consisting of metal sheet such as aluminum or synthetic resin sheet such as polyester, are laminated alternately and in such a manner that the direction of waves of the corrugated sheets 2 crosses rectangularly every step, and adhered to each other to obtain a cross-flow type heat exchanger 3 as shown in Fig. 2. When small concaves and convex are formed by a blast, etc. on the sheet surface, the sheets become hydrophilic and the surface area increases at the same time.

Aluminum sheet can be made hydrophilic by soaking the sheet in aqueous solution of sodium phosphate, sodium hypochlorite, chromic acid, phosphoric acid, oxalic acid or caustic soda or by soaking in boiling water in a short time to produce a hydrophilic substance on the surface of the aluminum sheet. When the sheet surface is changed to be hydrophilic, it can be prevented to decrease the ventilation of gas in small channels by the pressure drop by the water drop in the case that the fluid B is air or other gas.

As a cross-flow type heat exchanger 3, a combination of. flat sheets 1 and corrugated sheets 2 was shown as an example. When small waves are formed in the flat sheet part, the surface area is further increased to increase heat exchange efficiency. When the surfaces of the flat sheet 1 and the corrugated sheet 2 are made black, radiation and absorption of radiant heat increase to improve heat exchange efficiency.

As shown in Fig. 2 and Fig. 3, the cross-flow type heat exchanger 3 is set so that one group of small channels 4 are almost vertical and the other group of small channels 5 are almost horizontal. As shown in Fig. 3, a duct 8a and a duct 8b are installed at a flow inlet 4a and at a flow exit 4b of the group of small channels 4, respectively. A duct 8a is equipped with a fan Fa and a water spray 6. A duct 9a and a duct 9b are installed at a flow inlet and a flow outlet 5b of the group of small channels 5 (Fig. respectively.

The duct 9a is equipped with a fan F. In the drawing, Va is a valve that regulates spray amount of the water spray 6.

A water spray 6 is preferably possible to distribute uniformly water drops as small as possible such as an air mist nozzle. Water drops are preferably as small as possible such as around 10p m. When the largest diameter of water drops sprayed by an air mist nozzle is adjusted to around 280 Pt m, diameters of about 70 of water drops are smaller than 100 Ai m and the effect of the present invention is fully displayed.

An air mist nozzle is to spray using water and air, and sprayed water drops become smaller when both water and air are pressurized. The size of sprayed water drops is easily affected by air pressure and it is desirable to give pressure of more than 3 kgf/cm 2 A nozzle using liquid only may be adopted.

Now the action of this refrigerating device is explained. As shown in Fig. 3, the water spray 6 mentioned above is used for an outer air or room air flow A to spray to the air flow A a large amount of minute water drops so that temperature drops by heat of vaporization of water drops and relative humidity is increased. It is further made into an air flow Aa in which a large amount of minute water drops M float and the air flow Aa is sent into many flow passage inlets 4a of the heat exchanger 3 by emitting pressure of the fan Fa.

When high temperature air flow B is sent into a flow passage inlet 5a of the heat exchanger 3 by the fan F, on the other hand, the air flow Aa takes sensible heat of the high temperature air flow B through a partition wall 1 (cf.

Fig. 2) of the flow passage while the air flow Aa passes through the flow passage of the heat exchanger 3 to elevate temperature of the air flow Aa.

As a result, relative humidity of the air flow Aa lowers and a large amount of minute water drops M contained in the air flow Aa vaporize to lower temperature of the air flow Aa by the heat of vaporization of the water drops and to refrigerate the high temperature air flow B through the partition wall 1.

The refrigeration principle of this refrigerating device is explained further in detail. Vapor pressure of liquid is larger in liquid drop condition than in the condition when liquid keeps horizontal surface, and the smaller the liquid drop diameter is, the larger the vapor pressure of liquid is. This phenomenon is expressed as follows as Kelvin's formula log(pr/p)=26M/ prRT In this formula, p is vapor pressure on horizontal surface, pr is vapor pressure of liquid drop of radius r, M is mol mass, 6 is surface tension, p is liquid density, R is gas constant and T is absolute temperature.

Therefore, the smaller the radius of water drops is, the faster their vaporization is and the stronger the refrigeration effect becomes.

Furthermore in the process of vaporizing sprayed water drops M in the heat exchanger 3, the diameter of water drops M becomes smaller. And the smaller the diameter of water drops M becomes, the higher the vapor pressure becomes. Therefore vaporization of water drops M goes on acceleratedly in the heat exchanger 3. That is to say, minute water drops M vaporize in the heat exchanger 3 in an extremely short time to take away much heat of vaporization.

According to the formula mentioned above, in case of water of 189C, vapor pressure increases by 0.1 compared to that in the condition of water surface being flat when the radius of water drops becomes 1 u and by about when the radius of water drops becomes 10 m p. Vapor pressure is almost doubled when the radius of water drops is further lowered to 1 m g When air in which such a large amount of minute water drops M float is sent into the heat exchanger 3 as mentioned so far, observed is a phenomenon that water drops M vaporize rapidly in the heat exchanger 3.

Tests were performed using this refrigerating device. As shown in Fig.

4, an air flow A of temperature 25.99C, absolute humidity 8.05 g/kg and relative humidity 39 is passed through a water spray 6 to lower its temperature to 17.59C and at the same time to make it into an air flow Aa having 100% of relative humidity in which a large amount of minute water drops M float. This air flow Aa is sent into an inlet 4a of small channels 4 arranged almost perpendicularly in the heat exchanger 3 at the air flow speed of 2 m/sec.. On the other hand, a high temperature air flow B of temperature 70.69C, absolute humidity 10.44 g/kg and relative humidity 5.2 is sent into a flow inlet 5a of small channels arranged almost horizontally in the heat exchanger 3 at the air flow speed of 2 m/sec. by the blower F. The small channels 4 do not have to be exactly perpendicular: It is good enough if water drops pass through floating in the air. Fig. 5 is psychometric chart showing air refrigeration in this case and Table 1 is the test result.

Table 1 (with spray) Example 1 when the air flow B is of high temperature) Temperature Absolute Humidity Relative Humidity -C Ar Flow A 25.9 8.05 39 Air Flow Aa 17.5 100 Air Flow B 70.6 10.44 5.2 upply Air SA 18.6 10.44 78 ensible Heat xchange B-SA xchange- x 100 97.9% (1) Efficiency B- Aa Sensible heat exchange is performed between the high temperature air flow B and the air flow Aa, and temperature of the air flow Aa is continuously lowered by vaporization of minute water drops floating in the air flow Aa as mentioned above, refrigerating the air flow B to lower its temperature without increasing absolute humidity to make it into comfortable air of temperature 18.6°C, absolute humidity 10.44 g/kg and relative humidity 78 to be used as supply air SA. The air flow Aa becomes an air flow Ab of temperature 30.7°C and relative humidity 100 by passing through the heat exchanger 3. This air flow Ab is emitted in the atmosphere.

The sensible heat exchange efficiency n7i in this case becomes 97.9 as shown by the formula in Table 1, which shows that the heat exchange efficiency is very high. In the formula B, SA, Aa show temperature of each air. The amount of water drops sprayed is about 8 15 liters per hour.

The flow amount of the air flows A and B in this case is about 180 m 3 /hour.

The heat exchanger size is 0.25m X 0.25m 0.0625 m 2 in area, the surface area of its inlets 4a, 5a are 0.0625 m 2 respectively, and channel opening rate is about 40%. Therefore cross sectional area of small channels is 0.0625 m 2 x 40% 0.025 m 2 and, as wind velocity is 2 m/sec., wind volume is 0.025 m 2 x 2 m/sec. 180 mS/hour.

To compare with this, test data of the case using the same cross-flow type heat exchanger as used in Example 1 and without using a water spray in an air flow for refrigeration is shown in Fig. 6, Table 2 and psychometric chart in Fig. 7.

Table 2 Contrasting Example when the air flow B is of high temperature) Temperature Absolute Humidity Relative Humidity C (fg/kg) Air Flow A 22.3 7.58 Air Flow B 67.2 11.34 7 Supply Air Ba 36.0 11.34 31 Sensible Heat xchag B tBa Exchange 7 x 100 69.5% (2) Efficiency B- A In the formula B, Ba, A show tempetature of each air.

An air flow A of temperature 22.3°C becomes an air flow Ab of temperature 62.0 C by sensible heat exchange, and a high temperature air flow B of temperature 67.2°C becomes an air flow Ba of temperature 36.0°C by sensible heat exchange. Absolute humidity does not change in the air flow A and the air flow B.

The sensible heat exchange efficiency nr in this case is 69.5 as shown by formula in Table 2. When water is sprayed, the sensible heat exchange efficiency is 97.9 When water is not sprayed, it is 69.5 Thus spraying water increases the heat exchange efficiency by about 30 The other experimental conditions are same as the case of spraying water in Example 1.

Example 2 Using this refrigerating device similarly as shown in Fig. 8, air of temperature 25.7°C, absolute humidity 12.20 g/kg and relative humidity 59.0 is made into an air flow A of wind velocity 2 m/sec.. This is passed through a water spray 6 to obtain an air flow Aa of temperature 20.2C, relative humidity 100% and in which a large amount of misty minute water drops float uniformly.

This air flow Aa is sent into an inlet 4a of small channels 4 of a heat exchanger. On the other hand, high temperature air to be refrigerated of ~111 temperature 34.2 absolute humidity 14.41 g/kg and relative humidity 43 is made into an air flow B of wind velocity 2 m/sec., which is sent into an inlet 5a of small channels 5 of the heat exchanger. Sensible heat exchange is performed between the high temperature air flow B and the air flow Aa, and the air flow B becomes refrigerated air SA of temperature 20.60C, absolute humidity 14.41 g/kg and relative humidity 95 The air flow Aa becomes an air flow Ab of temperature 25°C and relative humidity about 100 which is emitted in the atmosphere. The psychometric chart in this case is shown in Fig. 9 and the test data in Table 3.

Table 3 (with spray) Exam le 1 (air flow B is of the normal temperature) Temperature Absolute Humidity Relative Humidity °C (g/kg) Air Flow A 25.7 12.20 59.0 Air Flow Aa 20.2 100 Air Flow B 34.2 14.41 43 Supply Air SA 20.6 14.41 Sensible Heat Exchange SA x 100 97.1% (3) Efficiency

B-A

As shown in the drawing, heat of vaporization of water drops in the air flow Aa is transmitted to the air flow B via the partition wall to lower temperature of the air flow B without changing absolute humidity, as shown in the psychometric chart, along the horizontal line of the psychometric chart until it reaches the point SA (20.6 and temperature of the air flow Aa rises until it reaches the point Ab along the line of relative humidity 100 Sensible heat exchange efficiency in this case is 97.1 as shown by formula in Table 3, which is almost same as sensible heat exchange efficiency of Example 1. That is to say, when temperature of the fluid B lowers, temperature of the supply air SA is 20.6 0C, which is appropriate for air conditioning, the amount of water sprayed may be decreased. The amount of water sprayed is about 8 liters/hour.

Example 3 As shown in Fig. 1, added to the device shown in Fig. 3 explained in Example 1 are a water tank D that receives water drops emitted together with an air flow Ab, a recirculation device of water pooled in said tank D, i.e., a pump P, a water leading pipe 10, an electric valve Va and a water level regulating device, a water level float Vs, a water level sensor Se, an electric valve Vb, a spray amount regulating device of a water drop spraying device 6, a thermocouple Ta, a thermocouple Tb, an electric signal amplifier C, and an electric valve Va. In the drawing, parts numbered in the same way as in Fig. 3 are not explained as they are the same parts explained in Fig. 3 in Example 1.

Installed is a water leading pipe 10 that recirculates water in a water tank D into a water spray 6, and it is provided with a pump P and an electric valve Va in the middle of it. A water supply pipe 11 is installed to a water tank D. A water level float Vs is floated on the water surface 13 in the water tank D. An on-off electromagnetic valve Vb at the water supply pipe 11 and a water level sensor Se are connected. As shown in the enlarged drawing of the part Q of Fig. 1, change of water level is caught by the water level float Vs and the water level sensor Se. When the water level goes down to 13 L, the electromagnetic valve Vb opens to supply water. When the water level goes up to 13 H, the electromagnetic valve Vb closes to stop water supply.

Arranged are a temperature sensor for gas flow A such as a thermocouple Ta on the upstream side of the water spray 6, another temperature sensor such as a thermocouple Tb in the fluid B. Said thermocouples Ta and Tb are connected with an electric signal amplifier C.

Temperature difference between these two thermocouples Ta and Tb is caught and put in the electric signal amplifier C. As the temperature difference increases, the electric valve Va is operated to increase the volume of water sprayed, and as the temperature difference lowers, the volume of water sprayed is lowered. The flow velocity of the air flow Aa is increased at need by increasing both the volume of water spray and the output of the fan Fa.

In this case, when sprayed amount from the water spray 6 is too much, minute water drops gather on the inner wall of small channels 4 of the heat exchanger 3 and drip down without fully vaporizing. The surface area of the water flow is extremely small compared with that of minute water drops, and there is too little water vaporization with the quantity of heat taken away from a high temperature air flow B to contribute to refrigeration.

Therefore temperature of the air flow Aa cannot be fully lowered, which makes full drop of the temperature of the high temperature air flow B impossible. When water is sprayed so that minute water drops M in the air flow Aa are contained uniformly and in a necessary amount, refrigeration efficiency becomes high and water can be saved.

Example 4 Instead of water (boiling point 100 used in the spray 6, used can be volatile organic liquid such as ethanol (boiling point 78.3 methyl acetate (boiling point 56.3 and methanol (boiling point 64.7 or mixed liquids of such volatile organic liquid and water.

Minute particles of desiccant silica gel are sprinkled on and adhered to both surfaces of a partition wall 1, and a corrugated sheet 2 of wave length 3.4 mm and wave height 1.7 mm (see Fig.2), both consisting of a 25 L -thick aluminum sheet, both of which are laminated alternately to obtain a crossflow type heat exchanger 3 of 250 mm X 250 mm X 250 mm in size. A refrigerating device shown in Fig. 10 is constructed using this heat exchanger 3. Fig. 10 also shows data of a case using this device and 45 aqueous solution of methanol instead of water used for the spray 6 in Examples 1 and 2. In this case, as aqueous solution of methanol is used instead of water, its boiling point goes down and temperature of the air flow A which was 25.9 °C lowered to 14.6 °C after spraying aqueous solution of methanol (air flow Aa).

Low temperature air SA of 17.2 °C was obtained by heat exchange of this air flow Aa of 14.6 °C and a high temperature air flow B of 51.3 °C.

Thus in order to obtain air SA of lower temperature, it is better to spray liquid which has low boiling point than spraying water only. Psychometric chart of Fig. 11 is one that shows condition changes of the air flow B SA and the air flow A Aa Ab mentioned above.

Example The device of the present example, as shown in Fig. 12, consists of the device explained in Example 1 to which added is a device for recirculating a gas flow Ab exhausted from the outlet 4b of the heat exchanger 3 to a highly humid gas flow Aa and to which a humidifier 7 is provided upstream the water spray 6. In Fig. 12, the outlet 4b of the heat exchanger 3 and the fan Fc are connected by a duct 8e, and the fan Fc and the flow passage of the highly humid gas flow Aa are connected with the duct 8d. A diverging duct K for sending in outer air OA when necessary is connected to a part of the duct 8e.

The humidifier 7 is provided with a valve V in the midway of a water supply pipe Wp so that water can be supplied when humidification is necessary. As a humidifier 7, there are an ultrasonic type and one using multiple woven cloths soaked in water.

A gas flow Aa is passed through the heat exchanger 3, and exhaust gas Ab from the outlet 4b is recirculated by a fan Fc to be used as a gas flow Ac.

This gas flow Ac is passed through a humidifier 7 when necessary and is made into the gas flow Aa in which a large amount of minute water drops M float by a spray 6 to be recirculated and sent into the heat exchanger 3.

In Fig. 12, the duct 8e is provided with a refrigerating part Co in the middle of it and many fins Fe are provided on the outer surface of the duct 8e which are covered by a cover. A fan Fd is connected to this. By refrigerating the fin Fe by the fan Fd, fluid Ab in the duct 8e is refrigerated to refrigerate and condense humidity in the highly humid fluid Ab.

Condensed water is pooled in the tank Da and water in the tank is drained and sent back to water spray humidifier 6 from time to time by a valve Vc.

The refrigeration method of fluid of the present invention has been so far explained in an example of refrigeration method of air using a cross-flow type heat exchanger. It is a matter of course that the same can be done in refrigeration of gas other than air or liquid such as water.

As a heat exchanger, it is also possible to use, instead of the cross-flow type mentioned above, a diagonal cross-flow type, a counter-flow type shown in Fig. 13 or one that is a combination of a counter-flow type and a cross-flow type shown in Fig. 14. In both of the counter-flow type heat exchanger shown in Fig. 13 and one that is a combination of a counter flow and a cross flow shown in Fig. 14, a gas flow Aa in which minute water drops float and fluid B pass through small channels in the direction of arrows in the drawings, and are exhausted as a gas flow Ab and fluid SA, respectively, to perform sensible heat exchange between both fluids of Aa and B. Also used can be a cross-flow type heat exchanger constructed with many spacers 12, between flat plates 1, in such a manner that the direction of a spacer crosses rectangularly every step as shown in Fig. 15, and a heat exchanger which is a counter-flow type or a combination of a counter-flow and a crossflow like the honeycomb laminate mentioned above.

Example 6 As shown in Fig. 16, a cross-flow type heat exchanger 3 of 250 mm x 250 mm x 250 mm and a spray humidifier 6 are arranged, and a dehumidifier rotor 14 is arranged ahead the heat exchanger 3. The dehumidifier rotor 14 is constructed by forming a honeycomb laminate, to which adsorbent or hygroscopic agent is combined, into a cylindrical shape of 320 mm diameter and 200 mm width. The dehumidifier rotor 14 is divided into an adsorbing zone 16 and a reactivating zone 17 by separators 15, The rotor is provided with a flowing passage by a duct (not shown in the drawing) as shown by arrows B HA SA. The dehumidifier rotor 14 is continuously rotated and operated at 16 r.p.h. in the direction of the arrow in the drawing. Outer air OA of temperature 34.0 0 C, absolute humidity 14.4 g/kg and relative humidity 43.1 is made into an air flow B by a fan Fb, and the air flow B is sent into the adsorbing zone 16 of the dehumidifier rotor 14 at wind velocity 2 m/sec..

Humidity in the air flow B is adsorbed and removed by this dehumidifier to obtain a dry air flow HA. Then the dry air flow HA is sent into the inlet 5a of horizontal small channels 5 of the heat exchanger 3.

Outer air OA is heated up to around 80 °C by the heater H and is sent into the reactivating zone 17 of the dehumidifier rotor 14 in the direction of the arrow in the drawing as reactivation air RA. The dehumidifier rotor 14 is dehumidified and reactivated in the reactivating zone 17, and the reactivation air RA is emitted in the air as humid exhaust air EA.

On the other hand, when an air flow A of temperature 26 °C and relative humidity 58 was humidified by the spray humidifier 6 to have 100 relative humidity, temperature of the air flow Aa became 17.0 'C.

Water is sprayed further to this air flow Aa so that minute water drops numerously float in it. The air flow Aa is sent into the flow inlet 4a of the heat exchanger 3.

The dry air flow HA mentioned above, by passing through the heat exchanger 3, performed sensible heat exchange with the air flow Aa in which minute water drops numerously float, and was refrigerated by heat of vaporization of minute water drops in the air flow Aa in the heat exchanger 3, which is similar to the explanation of Example 1, to obtain comfortable supply air SA of temperature 20.5 absolute humidity 4.5 g/kg and relative humidity 30 As is seen from this example, by dehumidifying outer air of temperature 34 0 C, absolute humidity 14.4 g/kg and relative humidity 43.1 and by passing the obtained dry air, whose temperature has been elevated by heat of adsorption of humidity and whose humidity has lowered, through the heat exchanger 3, refrigerated dry air of temperature 20.5 absolute humidity 4.5 g/kg and relative humidity 30 can be obtained. In using'this air for air conditioning, it can be appropriately humidified to obtain comfortable air conditions.

It is a matter of course that a two-cylindered type dehumidifier which is filled with hygroscopic agent, a cylindrical-type or a Kathabar (trade mark) type dehumidifier provided from Kathabar company, U.S.A can be used as a dehumidifier besides a rotary-type dehumidifier used in the present example. This Kathabar type dehumidifier is an apparatus in which an aqueous solution of lithium chloride is dropped in a container and at the same time air is sent in from a window of the container to absorb the humidity in the air in the lithium chloride solution.

Example 7 In the present example, explained is a process of dehumidification by a dehumidifier rotor after refrigeration of high temperature air of 70.0 °C by a heat exchanger.

As shown in Fig. 17, a spray humidifier 6 is installed on the upper side of a cross-flow type heat exchanger 3, and a dehumidifier rotor 14 behind the heat exchanger 3. When water is sprayed by a spray humidifier 6 to outer air OA of temperature 26.0 C, absolute humidity 12.2 g/kg and relative humidity 58 through a fan Fa till its relative humidity reaches 100 temperature of the outer air OA goes down to 17.5 Water is further sprayed to this air and the obtained air flow Aa, in which a large amount of minute water particles float, is passed through one flow passage 4a of the heat exchanger 3.

On the other hand, an air flow B of temperature 70.0 absolute humidity 14.4 g/kg and relative humidity 7 is sent into an inlet 5a of the heat exchanger 3 by the fan Fb at wind velocity of 2 m/sec.. The air flow B becomes a low temperature air flow Ba by sensible heat exchange in the heat exchanger.

Absolute humidity of the air flow Ba is substantially same as that of the air flow B. The air flow Aa becomes an air flow Ab of temperature 30.0 °C and relative humidity about 100 at the outlet of the heat exchanger 3 after passing through the heat exchanger and is exhausted in outer air. The dehumidifier rotor 14 is rotated and operated at 16 r.p.h. in the direction of the arrow in the drawing.

The refrigerated air flow Ba mentioned above is sent into the adsorbing zone 16 of this dehumidifier rotor 14 to obtain a dry air flow HA of temperature 55 absolute humidity 4.5 g/kg and relative humidity 5 by adsorbing/removing humidity. Operation of the dehumidifier rotor 14 is as explained in Example 5. Though dehumidification of high temperature air by adsorption system is extremely difficult, simple and effective dehumidification can be proceeded to obtain refrigerated dry air if a dehumidifier is used after refrigeration by a heat exchanger ahead the dehumidifier as shown in this example.

Example 8 The air flow HA obtained in Example 7 is 55.0 °C in temperature and in relative humidity. Its temperature is too high and its relative humidity is too low for general air conditioning. Therefore the present example is to pass this air flow HA further through the second heat exchanger 3b to obtain supply air SA of temperature and humidity appropriate for air conditioning.

As shown in Fig. 18, a high temperature air flow B is passed through the cross-flow type heat exchanger 3a and the dehumidifier rotor 14 as in Example 7 to obtain an air flow HA. As the operation so far is utterly same as in Example 7, repetition of explanation is omitted. The second cross-flow type heat exchanger 3b is installed behind the dehumidifier rotor 14, in the flow passage of the air flow HA flowing out of the outlet of process air. A spray humidifier 6b is installed upstream a flow passage 4 of the second heat exchanger 3b as in Example 7 mentioned above. As the effect of this second heat exchanger 3b is same as that of the heat exchanger 3 of Example 7 mentioned above, its explanation is omitted.

On the other hand, a dry air flow HA which has passed through the adsorbing zone 16 of the dehumidifier rotor 14 is sent into a flow passage inlet 5a of small channels 5 horizontally arranged in the heat exchanger 3b.

It performs sensible heat exchange with a refrigerated air flow Aa containing a large amount of minute water drops to obtain comfortable supply air SA of temperature 20.5 absolute humidity 4.5 g/kg and relative humidity 30 In regulating air conditions of supply air SA, the water amount sprayed to the air flow Aa is controlled to change temperature of supply air SA. When humidity of supply air SA is too low, lowering reactivation temperature of the dehumidifier rotor lowers dehumidifying efficiency of the dehumidifier rotor 14 to increase humidity of the supply air SA to carry out comfortable air conditioning at will.

In Examples 6 8 explained above, by spraying to the air flow Aa a liquid having low boiling point such as ethanol, methyl acetate and methanol, instead of water used in the spray humidifier, temperature of the supply air flow SA can be further lowered.

Moreover, an ultrasonic mist-forming device can be used as a mist forming means in every example. Besides an air mist nozzle, one fluid nozzle which does not use air can be used as a water spray. In the examples above, relative humidity was made 100 in one step of a spray humidifier and at the same time a large amount of minute water particles were made to float. It is also possible to install spray humidifiers in plural steps so that humidification is performed in the first step till relative humidity becomes 100 and a large amount of minute water particles are made to float in the second step. The essential thing is to pass through a heat exchanger air whose relative humidity is 100 and in which a large amount of minute water particles of around 10 A in diameter float.

A heat exchanger shown as an example in the above Examples was one that was formed by laminating a corrugated sheet and a flat sheet alternately. The present invention does not restrict a heat exchanger to this: Whatever is good as far as it has plural flow passages whose surface area is large such as a heat pipe provided at both ends with flow passages having many heat exchange fins.

Example 9 In Fig. 19, 18 is a known freezer containing a compressor (not shown in the drawing) inside, and 19 is a heat exchanger, one flow passage 20 of which is in a spiral state and the other flow passage 21 of which is in a jacket state surrounding the spiral flow passage Hot Freon gas or other refrigerants from the compressor flow in one flow passage 20 of the heat exchanger 19 and cooling water flows in the other flow passage 21 of the heat exchanger 19.

Other flow passage 21 of the heat exchanger 19 is connected to one flow passage of a cross-flow type heat exchanger 3 by a pipe 22 to which a circulating pump 23 is installed. That is to say, the heat exchanger 19 and the cross-flow type heat exchanger 3 are set so that cooling water circulates between them in airtight condition. In the drawing, 9a and 9b are chambers.

Fa is a blower whose inhaling side is open to the atmosphere and whose exhausting side is connected to the upper end of a chamber 24. The lower end of the chamber 24 is connected to the other flow passage inlet 4a of the cross-flow type heat exchanger 3. And the other flow passage outlet of the cross-flow type heat exchanger 3 is open to the atmosphere.

A spraying device 6 is installed inside the chamber 24 to make relative humidity of the air in the chamber 24 up to 100 and, at the same time, to bring about such condition that a large amount of minute water drops float, misty condition. As a spraying device 6, an air spraying nozzle, for example, is used to which a pressurizing pump P for water and a compressor are connected.

D is a water receiving tank which is installed under the cross-flow type heat exchanger 3 and which is provided with a drain pipe 26.

As shown in Fig. 20, this cross-flow type heat exchanger 3 is placed so that the axis of one group of its small channels 4 is almost vertical and that of the other group of its small channels 5 is almost horizontal, and a chamber 24 is installed at a flow inlet 4a of the small channels 4 and is provided with a blower Fa and a water spray 6. Chambers 9a, 9b are installed at a flow inlet 5a and at a flow outlet 5b of the small channels 5, and are connected to a pipe 22.

The action of the structure mentioned above is explained below. Now a refrigerating means using a cross-flow type heat exchanger 3 is explained.

A blower Fa is run to produce a gas flow A, to which water drops are sprayed by a water spraying device 6 to get a gas flow Aa. The quantity of water sprayed is to be more than the vaporizing quantity by spraying. Then a part of water drops sprayed vaporize, taking away evaporation heat to lower temperature of the gas flow Aa sent into the chamber 24. At the same time the air in the chamber 24, the gas flow Aa, comes to have relative humidity of 100 and comes into condition in which a large amount of minute water particles float in the air, misty condition.

Then this air, in which a large amount of minute water drops float, goes into one group of the small channels 4 of the cross-flow type heat exchanger 3.

When a freezer 18 (Fig. 19) is in operation, the refrigerant which is sent into one flow passage 20 of the heat exchanger 19 is high in temperature and performs heat exchange with water which is sent into the other flow passage 21 of the heat exchanger 19.

The water sent into the other flow passage 21 of the heat exchanger 19 is circulated by a pump 23 and is sent into the other group of the small channels 5 of the cross-flow type heat exchanger 3 through the pipe 22 and the chamber 9a. Sensible heat exchange is performed between one group of the small channels 4 and the other group of the small channels 5 through a separating wall 1. That is to say, the cooling water that passes through the other group of the small channels 5 is cooled by the gas flow Aa that passes through one group of the small channels 4 and, at the same time, the gas flow Aa that passes through one group of the small channels 4 is heated.

Then relative humidity of the gas flow Aa that passes through one group of the small channels 4 becomes lower than 100 and a large amount of minute water particles contained in it vaporize, taking away evaporation heat to cool the gas flow Aa.

In such a process, temperature of the gas flow Aa that passes through one group of the small channels 4 is kept almost constant in low degrees.

Therefore the cooling water that passes through the other group of the small channels 5 is cooled continuously in full range and in full length of the small channels 5a of the heat exchanger 3, and its temperature is kept almost constant.

In this case, when the sprayed quantity from the water spraying device 6 is too much, minute water drops gather on the separating wall in the small channels 4 of the cross-flow type heat exchanger 3 to cohere, forming huge water drops and water currents which, with much smaller surface areas compared with minute water drops, cannot fully lower temperature of the gas flow Aa by the heat taken from the refrigerant and, therefore, cannot fully lower temperature of the refrigerant. When minute water drops in the gas flow Aa are sprayed so that a little more than the necessary minimum is contained uniformly, cooling efficiency is high and, what is more, water can be saved.

Water drops that did not vaporize in the small channels 4 of the crossflow type heat exchanger 3 are pooled in the water tank D and are discharged from the drain pipe 26. As mentioned above, water quantity sprayed from the water spraying device 6 is almost same as vaporizing quantity in the small channels 4 of the cross-flow type heat exchanger 3.

Therefore water quantity pooled in the water tank D is little and there is no problem if all of it is thrown away. Thus, water sprayed from the water spraying device 6 is used without being circulated with no possibility of algae growing.

In the examples mentioned above, explained were examples using water as liquid to be cooled. It is also considered to add to the water antifreeze agent such as ethylene glycol to about 50 in volume, taking freezing in winter in consideration or to add an anticorrosive in order to prevent corrosion of the heat exchanger 19 and the cross-flow type heat exchanger 3.

Example Fig. 21 shows another example of a refrigerating device of a freezer in this example. The difference from the example of Fig. 19 is as follows: In Example 9 shown in Fig. 19, water is passed through the other group of the small channels 5 of the cross-flow type heat exchanger 3: In this example an air flow from a blower F is passed through the other group of the small channels 5 of the cross-flow type heat exchanger 3.

That is to say, F is a blower connected to the inlet of the chamber 9a.

The outlet of the chamber 9a is connected to the inlet of the other group of the small channels 5 of the cross-flow type heat exchanger 3. The outlet of the small channels 5 is connected to the inlet of the chamber 9b and the outlet of the chamber 9b is connected to a radiator 28.

A pipe 27 is installed so that refrigerant from the freezer 18 is passed through the radiator 28. As the structure of this example is same as that of Example 9 except the difference mentioned above, its explanation is omitted.

In this example, air passes through the other group of the small channels 5 of the cross-flow type heat exchanger 3 by the blower F, being cooled in the meantime, and reaches the radiator 28. Hot refrigerant from the freezer 18 is sent into the radiator 28 through the pipe 27 to emit heat of the refrigerant. Air that has passed through the small channels 5 is to be sent into this radiator 28.

In other words, the radiator 28 is cooled by the air flow cooled while passing through the other group of the small channels 5 of the cross-flow type heat exchanger 3, and the efficiency is much better than that of direct cooling type by outer air.

In the experiments by the applicants, a cross-flow type heat exchanger 3 same as that of Example 9 shown in Fig. 19 above was used: Air was passed through the small channels 4 of the cross-flow type heat exchanger 3 by the blower Fa at the velocity of 2 mn/sec. when outer air temperature was °C and relative humidity was 39 and 12 liters/hour of water was sprayed by the spraying device 6. Then temperature of the air that goes from the cross-flow type heat exchanger 3 to the radiator 28 was 18.6 °C and the cooling effect of the refrigerant became extremely high.

In this example, a refrigerating device of a freezer of the present invention can be installed ahead of a radiator of an air conditioning device already installed, and efficiency of a freezer of an air conditioning device already installed and of a refrigerator etc. can be increased through simple and easy work.

Effect of the Invention The present invention is constructed as explained above, and its principle is to pass as a gas flow for refrigeration a foggy gas flow Aa, having 100% of relative humidity and in which a large amount of minute water drops float uniformly, through one flow passage of a heat exchanger having plural fluid flow passages, and to pass fluid B to be refrigerated such as air or water through the other flow passage, thus contacting the gas flow Aa with minute water drops floating and the fluid B with a partition wall between them to heat the gas flow Aa to lower relative humidity of the gas flow Aa and to evaporate minute water drops, by whose heat of vaporization the gas flow Aa is refrigerated and fluid B is refrigerated too through the partition wall. Its characteristic is that it can regulate refrigeration level of the fluid B by controlling water amount sprayed by the water spray 6. Or by increasing sprayed water amount as temperature difference between the gas flow Aa and the high temperature air flow B grows larger, the fluid Aa increases refrigeration level of the high temperature air flow B in proportion to temperature difference between the fluid Aa and the high temperature air flow B and the air flow B can be refrigerated to an almost constant comfortable temperature. Furthermore, dry refrigerated air can be easily obtained by combining this refrigeration device and a dehumidifier.

As explained in Example 1, a cross-flow type heat exchanger 3 was provided with a spray humidifier 6. An air flow Aa with a large amount of minute water drops floating, as an air flow for refrigeration, refrigerated a high temperature air flow B with an extremely high sensible heat exchange efficiency of about 97 When the same cross-flow type heat exchanger that was used in Example 1 is used and no spray nor humidifier is used for an air flow for refrigeration, sensible heat exchange efficiency is 63 as shown as a contrasting example in Example 1. From this it can be seen that heat exchange efficiency in fluid refrigeration of the present invention is extremely high.

The energy consumption necessary for this heat exchange is about 250 W of operating energy of fans. The heat energy needed for refrigeration of fluid B, on the contrary, is one and a half times to several ten times of the energy consumption, for example, which value increases as temperature of the fluid B elevates.

This refrigeration device for fluid can be used for refrigeration of gas and also for desiccative refrigeration of gas by adding a dehumidifier as shown in Examples 6 8, thus for an air-conditioning apparatus. As the operation cost in this case is extremely low as mentioned above, it is not necessary to use room air in recirculation repeatedly for desiccative cooling in a closed room: Desiccative air-cooling can be continued, taking in fresh outer air continuously. Therefore increase of injurious gas such as carbon dioxide in room air can be completely prevented to provide comfortable space.

Furthermore, there is no environmental problem raised as Freon gas is not used like in prior air-cooling, and it has an excellent effect from a hygienic point of view as there is no need to use a compressor and hot air by waste heat might not generate bacteria or mold.

Claims

1. A method for refrigerating a fluid, comprising the steps of: adding a volatile liquid mist to a flow of a gas to saturate the cooling gas with vapor of the said volatile liquid, to cause a large amount of misty minute liquid drops of said volatile liquid to float in the gas and to form a cooling gas; passing the cooling gas through first flow channels of a heat exchanger having first and second flow channels, the first flow channels being non-porous and being separated from the second flow channels; passing the fluid through the second flow channels of the heat exchanger, so that heat from the fluid is transferred to the cooling gas, while the cooling gas passes through the first flow channels of the heat exchanger to elevate the temperature of the cooling gas; allowing a portion of the minute liquid drops floating in the cooling gas to vaporize due to the elevated temperature of the cooling gas; continuously lowering the temperature of the cooling gas by the heat of vaporization of the minute liquid drops evaporated in step and continuously refrigerating the fluid through heat exchange with the cooling gas having a temperature continuously lowered in step

2. A method for refrigerating a fluid according to claim 1, wherein: a temperature difference is evaluated between the cooling gas and the fluid before the cooling gas and the fluid are passed through the heat exchanger; and ,o the amount of minute liquid drops caused to float in step is changed according to corresponding changes in the temperature difference between the cooling gas and the fluid. 25

3. A method for refrigeration of fluid according to claim 1, wherein: oo•;a temperature difference is evaluated between the cooling gas and the fluid before the cooling gas and the fluid are passed through the heat exchanger; the cooling gas is passed through the heat exchanger at a flow velocity; and the flow velocity at which the cooling gas flow is passed through the heat S 30 exchanger is changed corresponding to changes in the temperature difference between the cooling gas and the fluid.

4. A method for refrigerating a fluid according to any one of claims 1 to 3, wherein step comprises the substeps of: (al) adding the volatile liquid to saturate the cooling gas; and (a2) after step adding the volatile liquid to cause a large amount of misty minute liquid drops to flow in the cooling gas.

A method for refrigerating a fluid according to any one of claims 1 to 4, wherein: the cooling gas enters and leaves the first flow channels of the heat exchanger respectively through an inlet and an outlet of the first flow channels; and [N:\LIBZZ]OOO89:NJC 23 the cooling gas is recirculated such that the volatile liquid mist is added to the cooling gas after the cooling gas exits the outlet and before the cooling gas reenters the inlet.

6. A method for refrigerating a fluid according to any one of claims 1 to wherein the volatile liquid is selected from the group consisting of water, a volatile organic liquid and a mixture of water and a volatile organic liquid.

7. A method for refrigerating a fluid according to any one of claims 1 to 6, wherein the volatile liquid is added in step by spraying the volatile liquid in a stream of air from a gas/liquid mixing nozzle. o

8. A method of refrigerating a fluid according to any one of claims 1 to 7, wherein the diameter of misty minute liquid drops is not more than 2 8 0gm.

9. A method for refrigerating a fluid, according to any one of claims 1 to 8, further comprising the step of dehumidifying the fluid before passing the fluid through the second flow channels of the heat exchanger.

10. A method for refrigerating a fluid, according to any one of claims 1 to 9, further comprising the step of dehumidifying the fluid after the fluid passes through the second flow channels of the heat exchanger.

0011. A method for refrigerating a fluid, according to any one of the preceding claims further comprising the step 20 passing the fluid dehumidified in step through the second flow channels of the second heat exchanger, so that heat from the fluid is transferred to the 0 •cooling gas, while the cooling gas passes through the first flow channels of the second *4 heat exchanger to elevate temperature of the cooling gas and vaporize a portion of the minute liquid drops floating in the cooling gas. :0 25

12. A device for refrigerating a fluid, comprising: 000 mist-forming means for adding a liquid mist of a volatile liquid to a flow of 40 gas to saturate the gas with volatile liquid vapor, to cause a large amount of misty minute Sliquid drops to float in the gas and to form a cooling gas; a heat exchanger having first and second flow channels, the first flow channels 00*00 30 being non-porous and being separated from the second flow channels; "means for directing the cooling gas through the first flow channels of the heat exchanger so that a portion of the minute liquid drops floating in the cooling gas is allowed to vaporize due to elevated temperature of the cooling gas; and means for directing the fluid through the second flow channels of the heat exchanger.

13. A device for refrigerating a fluid according to claim 12, further comprising means for introducing a volatile liquid vapor provided upstream from the mist-forming means such that the gas flows from the means for introducing a volatile liquid vapor, and flows to the mist forming means. (N:\LIBZZ]00089:NJC 24

14. A device for refrigerating a fluid according to claim 12 or 13, further comprising: ductwork for directing the cooling gas from an outlet of the first flow channels of the heat exchanger to an inlet of the first flow channels of the heat exchanger; and a fan provided in the ductwork and directed toward the inlet of the first flow channels of the heat exchanger.

A device for refrigerating a fluid according to any one of claims 12 to 14, wherein the heat exchanger is selected from the group consisting of a heat exchanger in which the first and second flow channels extend generally perpendicular to one another, a lo heat exchanger in which the first and second flow channels extend diagonal to one another, a heat exchanger in which the first and second flow channels extend generally parallel to one another, a combination heat exchanger in which the first and second flow channels extend generally perpendicular to one another toward inlets and outlets of the flow channels but extend generally parallel to one another toward middle portions of the flow channels, the combination heat exchanger having alternating layers of flat sheets and corrugated sheets laminated together.

16. A device for refrigerating a fluid according to any one of claims 12 to wherein the heat exchanger is selected from the group consisting of a heat exchanger in which the first and second flow channels extend generally perpendicular to one another, a heat exchanger in which the first and second flow channels extend diagonal to one another, a heat exchanger in which the first and second flow channels extend generally parallel to one another, a combination heat exchanger in which the first and second flow channels extend generally perpendicular to one another toward inlets and outlets of the flow channels but extend generally parallel to one another toward middle portions of the S 25 flow channels, the combination heat exchanger having alternating layers of flat sheets and S* spacers laminated together, the spacers extending the direction of the flow channels.

17. A device for refrigerating a fluid according to any one of claims 12 to 16, o o wherein heat exchanger has a surface which is hydrophilic.

18. A device for refrigerating a fluid according to any one of claims 12 to 17, 30 wherein the heat exchanger has walls extending between the first and second flow channels, and minute particles are rigidly adhered onto the walls of the heat exchanger.

19. A device for refrigerating a fluid according to claim 18, wherein the minute particles are of adsorbent.

A device for refrigerating a fluid according to any one of claims 12 to 19, further comprising dehumidifying means provided on an upstream side of the second flow channels of the heat exchanger for dehumidifying the fluid before the fluid is directed through the second flow channels of the heat exchanger.

21. A device for refrigerating a fluid according to any one of claims 12 to further comprising dehumidifying means provided on a downstream side of the second [N:\LIBZZI0089:NJC flow channels of the heat exchanger for dehumidifying the fluid after the fluid is directed through the second flow channels of the heat exchanger.

22. A device for refrigerating a fluid according to any one of claims 12 to 21, comprising: mist forming means for adding a liquid mist of a volatile liquid to a flow of gas to saturate the gas with liquid vapor, to cause a large amount of misty minute liquid drops to float in the gas and to form a cooling gas; first and second heat exchangers respectively having first and second flow channels; o means for directing the cooling gas through the first flow channels of the first and second heat exchangers; means for directing the fluid through the second flow channels of the first heat exchanger; a dehumidifier provided on a downstream side of the second flow channels of the first heat exchanger and on an upstream side of the second flow channels of the second heat exchangers; means for directing the fluid from the second flow channels of the first heat exchanger to the dehumidifier; and means for directing the fluid from the dehumidifier to the second flow channels of the second heat exchanger. i i

23. A device for refrigerating a fluid according to claim 22, further comprising means for introducing a volatile liquid vapor provided upstream from the mist-forming means such that the gas flows from the means for introducing a volatile liquid vapor, and flows to the mist forming means.

24. A device for refrigerating a fluid according to claim 22, further comprising: ductwork for directing the cooling gas from an outlet of the first flow channels •:of the heat exchanger to an inlet of the first flow channels of the heat exchanger; and a fan provided in the ductwork and directed toward the inlet of the first flow channels of the heat exchanger. S* 30

25. A device for refrigerating a fluid according to claim 22, wherein the heat exchanger is selected from the group consisting of a heat exchanger in which the first and S second flow channels extend generally perpendicular to one another, a heat exchanger in S which the first and second flow channels extend diagonal to one another, a heat exchanger S• in which the first and second flow channels extend generally parallel to one another, a combination heat exchanger in which the first and second flow channels extend generally perpendicular to one another toward inlets and outlets of the flow channels but extend generally parallel to one another toward middle portions of the flow channels, the combination heat exchanger having alternating layers of flat sheets and corrugated sheets laminated together. [N:\LIBZZ]0OOO89:NJC 26

26. A device for refrigerating a fluid according to claim 22, wherein the heat exchanger is selected from the group consisting of a heat exchanger in which the first and second flow channels extend generally perpendicular to one another, a heat exchanger in which the first and second flow channels extend diagonal to one another, a heat exchanger in which the first and second flow channels extend generally parallel to one another, a combination heat exchanger in which the first and second flow channels extend generally perpendicular to one another toward inlets and outlets of the flow channels but extend generally parallel to one another toward middle portions of the flow channels, the combination heat exchanger having alternating layers of flat sheets and spacers laminated o together, the spacers extending the direction of the flow channels.

27. A device for refrigerating a fluid to cool a radiator comprising: mist forming means for adding a liquid mist for a volatile liquid to a flow of gas to saturate the gas with volatile liquid vapor, to cause a large amount of misty minute liquid drops to float in the gas and to form a foggy gas stream; a first heat exchanger having first and second groups of channels, the first flow channels being non-porous and being separated from the second flow channels; means for directing the foggy gas stream through the first group of channels of the first heat exchanger so that a portion of the misty minute liquid drops floating in the foggy gas stream is allowed to vaporize due to elevated temperature of the cooling gas; means for directing the fluid through the second group of channels of the first heat exchanger; a second heat exchanger connected to the radiator and provided downstream from the second group of channels of the first heat exchanger for exchanging heat between the fluid directed through the first heat exchanger and the radiator.

28. A device for refrigerating a heated fluid to cool a radiator according to claim 9. 27, wherein the fluid is selected from the group consisting of water and a liquid mixture containing water. o

•29. A device for refrigerating a fluid to cool a radiator according to claim 27, wherein the fluid is a gas.

30 30. A method for refrigerating a fluid according to any one of claims 1 to 11, further comprising the steps of: providing aluminum sheets; soaking the aluminum sheets in a solution selected from the group consisting of an aqueous solution of sodium phosphate, sodium hypochlorite, chromic acid, phosphoric acid, oxalix acid, caustic soda and boiling water; forming the heat exchanger having first and second flow channels from the aluminum sheets soaked in the solution.

31. A device for refrigerating a fluid according to claim 12, wherein the heat exchanger is formed of metal sheets having concave and convex surface portions.

32. A method for refrigerating a fluid, comprising the steps of: [N:\LIBZZ000IO89:NJC 27 adding a volatile liquid mist to a flow of a gas to saturate the cooling gas with vapor of the said volatile liquid, to cause a large amount of misty minute liquid drops of said volatile liquid to float in the gas and to form a cooling gas; passing the cooling gas through first flow channels of a heat exchanger s having first and second flow channels such that the minute liquid drops are entrained across an entire cross section of the first flow channels, the first flow channels being separated from the second flow channels; passing the fluid through the second flow channels of the heat exchanger, so that heat from the fluid is transferred to the cooling gas, while the cooling So gas passes through the first flow channels of the heat exchanger to elevate the temperature of the cooling gas; allowing a portion of the minute liquid drops floating in the cooling gas to vaporize due to the elevated temperature of the cooling gas; continuously lowering the temperature of the cooling gas by the heat of vaporization of the minute liquid drops evaporated in step and continuously refrigerating the fluid through heat exchange with the cooling gas having a temperature continuously lowered in step

33. A device for refrigerating a fluid, comprising: mist-forming means for adding a liquid mist of a volatile liquid to a flow of gas to saturate the gas with volatile liquid vapor, to cause a large amount of misty minute liquid drops to float in the gas and to form a cooling gas; a heat exchanger having first and second flow channels, the first flow channels being separated from the second flow channels; *.means for directing the cooling gas through the first flow channels of the heat 25 exchanger so that the minute liquid drops are entrained across an entire cross section of the first flow channels and so that a portion of the minute liquid drops floating in the cooling gas is allowed to vaporiae due to elevated temperature of the cooling gas; and S• means for directing the fluid through the second flow channels of the heat exchanger. 30

34. A method for refrigerating a fluid, comprising the steps of: adding a volatile liquid mist to a flow of a gas to saturate the cooling gas S with vapor of the said volatile liquid, to cause a large amount of misty minute liquid o drops of said volatile liquid to float in the gas and to form a cooling gas; passing the cooling gas through first flow channels of a heat exchanger having first and second flow channels, the first flow channels being separated from the second flow channels; passing the fluid through the second flow channels of the heat exchanger, so that heat from the fluid is transferred to the cooling gas, while the cooling gas passes through the first flow channels of the heat exchanger to elevate the temperature of the cooling gas; [N:\LIBZZ]0OOO89:NJC 28 allowing a portion of the minute liquid drops floating in the cooling gas to vaporize due to the elevated temperature of the cooling gas; continuously lowering the temperature of the cooling gas by the heat of vaporization of the minute liquid drops evaporated in step continuously refrigerating the fluid through heat exchange with the cooling gas having a temperature continuously lowered in step and allowing a portion of the minute liquid drops floating in the cooling gas to exit the first flow of channels after passing through the heat exchanger.

A device for refrigerating a fluid, comprising: mist-forming means for adding a liquid mist of a volatile liquid to a flow of gas to saturate the gas with volatile liquid vapor, to cause a large amount of misty minute liquid drops to float in the gas and to form a cooling gas; a heat exchanger having first and second flow channels, the first flow channels being separated from the second flow channels; means for directing the cooling gas through the first flow channels of the heat exchanger so that a portion of the minute liquid drops floating in the cooling gas is allowed to vaporize due to elevated temperature of the cooling gas and so that a portion of the minute liquid drops floating the cooling gas is allowed to exit the first flow of channels alter passing through the heat exchanger; and means for directing the fluid through the second flow channels of the heat exchanger.

36. A device for refrigerating a fluid, comprising: mist-forming means for adding a liquid mist of a volatile liquid to a flow of S: 2gas to saturate the gas with volatile liquid vapor, to cause a large amount of misty minute 25 liquid drops to float in the gas and to form a cooling gas; *a heat exchanger having first and second flow channels, the first flow channels being separated from the second flow channels, the first flow channels not having a water retention covering formed thereon; o• *means for directing the cooling gas through the first flow channels of the heat S 30 exchanger so that a portion of the minute liquid drops floating in the cooling gas is allowed to vaporize due to elevated temperature of the cooling gas; and means for directing the fluid through the second flow channels of the heat exchanger

37. A device for refrigerating a fluid substantially as hereinbefore described with reference to any one of the accompanying drawings and/or examples. [N:\LIBZZ0IOO89:NJC 29

38. A method for refrigerating a fluid substantially as hereinbefore described with reference to any one of the accompanying drawings and/or examples. Dated 21 May, 1999 Seibu Giken Co., Ltd. Patent Attorneys for the Applicant/Nominated Person SPRUSON FERGUSON a a. a a a a. a a a a a. a a a a a a a. a a. a. IN:\LIBZZ]0OOB9:NJC