Refrigeration – Processes – Gas and liquid contact
Reexamination Certificate
2001-07-27
2002-12-24
Doerrler, William C. (Department: 3744)
Refrigeration
Processes
Gas and liquid contact
C062S305000, C062S309000, C062S310000, C062S314000
Reexamination Certificate
active
06497107
ABSTRACT:
FIELD OF THE INVENTION
1. The present invention relates to methods of indirect-evaporation cooling of fluids and to heat exchange apparatus for affecting these methods.
2. The invention can be used for air conditioning, as well as cooling liquids and gases in different technological processes. It can be used to cool materials that can be conveyed along the heat transfer surfaces of the apparatus by methods other than fluidization.
BACKGROUND
The use of Evaporative methods to cool gases is well-known. The use of adjacent channels or heat transfer services to allow an evaporation in one channel to provide cooling for material in the second channel is also well-known, see. Niehart 2,174,060.
The methods and apparatus to cool air through evaporation have proved useful over many years. However they have certain drawbacks and limitations due to their designs.
There is known in the art a method of indirect-evaporation cooling of air, comprising cooling the flow of outside air over a heat exchange apparatus (USSR Patent No. 979796).
The outside air is pushed over a heat transfer surface, or moisture proof plates of the Dry Channel. The apparatus is comprised of a number of vertical moisture-proof plates which divides alternately Dry Channels and Wet Channels. At the outlet from the Dry Channel the flow of air is divided into two flows, namely, the cooled product flow and working flow to the evaporation or wet channel. The cooled flow goes to the consumer, and the evaporative flow is directed in counter flow of the Dry Channel, in the Wet Channel. The flows are controlled by the creation of aerodynamic resistance at the Dry Channel outlet. The heat transfer between the dry and Wet Channels causes heat to be drawn out of the outside air in the Dry Channel across the heat transfer surface and into the evaporation of the water in the Wet Channel. Cooling the air by the heat transfer surface occurs from the inlet of the Dry Channel to the exit. This allows air temperatures at the end of the Dry Channel to approach the dew point temperature of the air entering the Dry Channel.
The essential disadvantages of the described method and the apparatus for effecting same are: 1) the Product Fluid can not be cooled even in an ideal case lower than the temperature of the dew point of outside air; 2) the impossibility of cooling materials other than air or gas and; 3) difficult to realize cooling process for use in vehicles.
In addition to the above indirect-evaporation cooler there is a conceptual method and design apparatus for Evaporating and Cooling Water disclosed in Maisotsenko patent USSR Patent No. 690271 and USSR Patent No. 641260 where by single pass of air is used to cool water. In this method and apparatus the outside air flow is pushed down a Dry Channel with a heat transfer surface between the dry and wet channels and turned 180 degrees at the end of the channel and pushed up in counter flow across the water wetted heat transfer surface. Evaporation of water from the Wet Channel then draws heat across the heat transfer surface cooling the air in the Dry Channel and also cooling the water in the Wet Channel. Enough water is drawn over the Wet Channel to allow evaporation and collection of cooled water at the bottom of the channel which becomes the cooled product. Cooling the air in the Dry Channel allows for water temperatures at the bottom of the channel to approach the dew point temperature of the outside air.
The essential disadvantages of the described method and the apparatus for effecting same are: 1) the water being cooled can not be cooled even in an ideal case lower then the dew point temperature of outside air; 2) The ability to cool only water; 3) This process does not use an induced draft exhaust system and; 4) The description of the materials and accessories needed to design and make the cooler make for impractical application.; 5) Cooling potential of this evaporation process is limited; 6) The heat transfer rate in the channels, especially the Dry Channels is low.
Rotenberg 5,187,946, which is copied from Russian patent 2046257 Maisotsenko, there is disclosed a Wet-Dry Channel heat exchange system with an evaporative cooler. This does not address the issues of the limitation of ambient air, the limited efficiency of this design or the separate product channel being cooled by the wet channel.
The use of desiccants in evaporative coolers is common, see Belding 6,050,100, where the desiccant dehumidifies the air, both the air that goes to a dry side of an indirect evaporative cooler and the air that is separated and sent to the wet side to evaporate the water and cool the dry side air flow for later use. The desiccant is by way of a desiccant wheel. Additionally, the use of the desiccant and separately treating the two air streams in Belding yields a primary stream for the dry side that is more humid and cooler than the drier and warmer secondary stream that is used for the wet side.
Unlike the disclosed invention herein, Belding does not use the same flow for the dry and wet side flows. As a result, the cooling is not great and there is no separation of product so only air can be cooled. Finally, the method requires complex components and separate treatment of the flows with added mechanics and energy requirements.
Lowenstein in 5,351,497 and his paper on “Seasonal Performance of a Liquid Desiccant Air Conditioner” ASHRAE Symposia 1995 makes use of liquid desiccant on the dry side of an indirect evaporative cooler. Similar to Belding, the dry side air is separate and is the cooled product air.
Lowenstein uses the liquid desiccant to dehumidify the desired air flow for a living area, and the evaporative cooling is used to aid in absorbing the latent heat that is released by the dehumidification.
Lowenstein's absorber, throughout makes use of liquid desiccant for dehumidifying air, does not make use of the unique feature of the within application. It does not give the advantages of lower temperature and controlled humidity.
Separate absorbers, using liquid desiccants were also discussed in Martinez and Khan, “Heat and Mass Transfer Performance Analysis of a Compact, Hybrid Liquid Desiccant Absorber”, 1996 IEEE. The discussion teaches a result contrary to the within disclosure that such an absorber could not be used alone to condition and cool air for living space.
The objectives of this invention is to make an improved method and apparatus for evaporation of a liquid to provide cooling for gases, liquids or other materials. The invention allows for cooling to a lower temperature than other methods. Its further objective is to make use of the cool product gas flow to cool other materials in an improved way without adding vapor or humidity to the product.
Further objectives of the invention is to make use of drying agents or desiccants to enhance the efficiency of the invention and its ability to cool. A further innovation is to make use of solid desiccants on a membrane or substrate to allow transpiration of vapor and fluid that is absorbed in the dry channel by the desiccants and then released in the wet channel by evaporation processes and thus cool the membrane and the dry channel.
The water vapor transpires through the solid desiccant and membrane.
Additional objects of the invention are to allow the desiccants to be concentrated and recycled to provide more efficiency to the cycle. The invention uses the recycling of the desiccant in combination with the use of the desiccant as part of the wet channel to accomplish both objects.
SUMMARY OF INVENTION
The main object of the invention is to provide an economical and environmentally safe method of cooling by indirect-evaporation and heat exchange apparatus, wherein the Product Fluid can be cooled to or lower than the dew point temperature of outside air. The object set forth is solved in different ways by using a core piece of heat and mass exchange apparatus in combination with the cooling process or processes that are desired. This core piece of apparatus can deliver cooling fluid by either producing cooled liquid or c
Gillan Alan D.
Gillan Leland E.
Heaton Timothy L.
Maisotsenko Valeriy
Doerrler William C.
Dorr, Carson , Sloan & Birney, P.C.
Idalex Technologies, Inc.
Zec Filip
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