Patent Application
20050046050
Evaporative coolers are well know and used in warm climates to cool the air. Conventional evaporative coolers work by drawing air from outside through a rigid media soaked with water. As the air flows through the media soaked with water, the water is evaporated by the outside air thereby lowering the temperature of the air. The cooled air is then directed into the area to be cooled.
Conventional evaporative coolers include a number of elements stored in a housing. These elements typically include an air blower, a media pad, a water distribution system, and an electric motor. One type of conventional media pad for an evaporative cooler includes aspenwood excelsior. However, such aspenwood excelsior is subject to degradation and has a relatively short useful life.
Another type of conventional media pad for an evaporative cooler include a cross-corrugated, rigid, non-perforated pad. However, such conventional media pads for evaporative coolers are relatively expensive.
Humidifiers are also well known. Humidifiers supply moisture to the air and maintain desired humidity conditions. Humidifiers typically include a number of elements including a humidifier pad. Conventional humidifier pads include superposed sheets or layers of perforated material which are wetted. A relatively low flow of air is directed into such conventional humidifier pads to cause evaporation of the water. The evaporated water is carried off in the air passing through the humidifier. However, such conventional humidifier pads do not allow for sufficient air flow through the pad sufficient to significantly lower the temperature of the air as do media pads of conventional evaporative coolers.
Accordingly, it would be desirable to provide in an evaporative cooler a media pad of the type conventionally used in a humidifier that has substantial wicking characteristics and also allows for sufficient air flow through the pad(s), for example 3000 cubic feet per minute. Additionally, it would be desirable to provide a media pad for an evaporative cooler that has surfaces that spread water rapidly. Further, it would be desirable to provide a media pad for an evaporative cooler that allows for sufficient air flow through the pad to lower the temperature of the air. It would also be desirable to provide a media pad for an evaporative cooler that has a longer useful life than conventional aspenwood excelsior pads. It would also be desirable to provide a media pad for an evaporative cooler that has a lower cost than conventional cross-corrugated, rigid non-perforated pads. It would still further be desirable to an evaporative cooling system with flexible media having one or more of these or other advantageous features.
A first embodiment relates to a media pad for an evaporative cooler. The media pad includes a plurality of superposed sheets of slit and expanded wicking paper joined together. A pressure drop across the media pad is less than about 0.25 inches of water at an air speed of 225 feet per minute and at about room temperature.
The first embodiment wherein a pressure drop across the media pad is less than about 0.17 inches of water at an air speed of 225 feet per minute and at room temperature.
The first embodiment further comprising a plurality of sheets of slit and expanded substantially nonwicking paper.
The first embodiment wherein a major surface of at least one of the sheets of nonwicking paper is interposed in parallel relationship between, and coupled to, a major surface at least one of the sheets of wicking paper.
The first embodiment wherein the major surface of each of the sheets of nonwicking paper is disposed in contact with the major surface of one of the sheets of wicking paper.
The first embodiment wherein the sheets of wicking paper comprise at least about one-third of the total number of sheets of wicking paper and sheets of nonwicking paper.
The first embodiment wherein the sheets of wicking paper comprise between about one-half to about three-quarters the total number of sheets of wicking paper and sheets of nonwicking paper.
The first embodiment wherein the sheets of wicking paper comprise moisture absorbent paper.
A second embodiment relates to a media pad for an evaporative cooler. The media pad includes means for providing capillary dispersion of water. The media pad also includes means for providing the flow of air through the means for providing capillary dispersion of water. The means for providing capillary dispersion of water has a Klemm greater than about 3 inches in 10 minutes.
The second embodiment wherein the means for providing capillary attraction has a Klemm greater than about 6 inches in 10 minutes.
The second embodiment wherein the means for providing the flow of air provides a pressure drop of less than about 0.2 inches of water at room temperature and an air speed of 225 feet per minute.
The second embodiment wherein the means for providing capillary attraction comprises paper that is water absorbing.
The second embodiment wherein the means for providing capillary attraction comprises wicking paper.
The second embodiment wherein the means for providing the flow of air comprises a plurality of openings in, the wicking paper.
The second embodiment wherein the openings have a generally diamond shape.
A third embodiment relates to an evaporative cooling system. The evaporative cooling system includes a housing having with an evaporative media pad that is flexible. The evaporative cooling system also includes a water circulation system configured to disperse water over the evaporative medium pad. A first portion of the pad is wetted by the water circulation system so that the water is dispersed to a second portion of the pad.
The third embodiment wherein the first portion is an upper portion.
The third embodiment wherein the second portion is a lower portion.
The third embodiment wherein the evaporative media pad comprises paper that is water absorbing.
The third embodiment wherein the evaporative media pad comprises wicking paper.
The third embodiment wherein the moisture absorbent paper has a Klemm greater than about 3 inches in 10 minutes.
The third embodiment wherein the moisture absorbent paper has a Klemm greater than about 6 inches in 10 minutes.
The third embodiment wherein the moisture absorbent paper comprises openings sufficient to provide a pressure drop of less than about 0.2 inches of water at room temperature and an air speed of 225 feet per minute.
Referring to
Media pad 10 is modified from the humidifier pads of the '564 patent in at least two respects: (1) superposed layers or sheets 12, 24, 16 and 18 of media pad 10 have opening or apertures 20 that allow for sufficient flow of air through media pad 10 (such as 3000 cubic feet per minute for the media pads in an evaporative cooler) to provide a suitable cooling effect; and (2) media pad 10 having sheets 12, 14, 16 and 18 in the evaporative cooler provide for sufficient cooling (rather than humidification) of the air. Other than these modifications, the construction and performance of media pad 10 is similar to that of the humidifier pad of the '564 patent.
Referring to
Sheets 12 and 16 are moisture absorbent or wicking paper according to a preferred embodiment. Sheets 14 and 18 are substantially nonwicking paper according to a preferred embodiment. The ratio of wicking sheets to nonwicking sheets in the media pad is greater than about 30 percent, more suitable greater than about 50 percent of the total number of paper sheets (e.g. 8 wicking sheets and 8 non-wicking sheets) according to one embodiment. In another embodiment, the ratio of wicking sheets to nonwicking sheets in the media pad is less than about 75 percent of the total number of paper sheets (e.g. about 12 nonwicking sheets interposed between and among about 16 nonwicking sheets). According to one embodiment, the media pad has 10 wicking sheets and 6 non-wicking sheets. According to other alternative embodiments, the media pad may comprise only wicking sheets or only non-wicking sheets of any combinations thereof.
To manufacture the sheets, a cut or perforation shown as a slit edge 28 in
Referring to
According to a preferred embodiment, the airflow through the pad is in the direction normal to the major surface of the sheet shown in the direction of an arrow 72 in
It is desirable to maximize the airflow through the media pad to provide sufficient evaporation of the water for the evaporative cooler. It is also desirable to minimize the change in pressure of the flow of air (e.g. at about 200 to 300 feet per minute) through the media pad. As used in this disclosure, the term “pressure drop” means and includes the change in the pressure of the flow of air as it enters the media pad at room temperature and as it exits the media pad (i.e. the static pressure difference between the air inlet side and the air outlet side of the media pad). The pressure drop is relatively small due in part to the size and/or alignment of the apertures of the media pad. Very low pressures are generally expressed in inches of water (rather than pounds-force/square inch, pounds per square inch or psi).
A manometer may be used to measure such pressure drop across the media pad according to a preferred embodiment. A manometer is a pressure gauge or instrument for comparing the pressure of gasses. A manometer operates on the principle of allowing gas to exert its elastic force in raising a column of liquid (e.g. mercury, water, etc.) in an open tube. A conventional manometer includes a U-shaped tube with water in it, and as pressure is applied to one side of the tube the water rises in the other side of the tube and the pressure reading is provided in inches of water.
According to one embodiment, the pressure drop across the media pad of a flow of air entering the media pad at about 225 feet per minute at about room temperature is less than about 0.8 inches of water (e.g. about 0.0289018 psi). According to another embodiment, the pressure drop across the media pad of a flow of air entering the media pad at about 225 feet per minute at about room temperature is less than about 0.7 inches of water (e.g. about 0.0252891 psi). According to another embodiment, the pressure drop across the media pad of a flow of air entering the media pad at about 225 feet per minute at about room temperature is less than about 0.31 inches of water (e.g. about 0.0111995 psi). According to another embodiment, the pressure drop across the media pad of a flow of air entering the media pad at about 225 feet per minute at about room temperature is less than about 0.26 inches of water (e.g. about 0.0093931 psi). According to another embodiment, the pressure drop across the media pad of a flow of air entering the media pad at about 225 feet per minute at about room temperature is less than about 0.17 inches of water (e.g. about 0.0061416 psi). According to another embodiment, the pressure drop across the media pad of a flow of air entering the media pad at about 225 feet per minute at about room temperature is less than about 0.015 inches of water (e.g. about 0.0054191 psi). According to a preferred embodiment, the pressure drop across the media pad of a flow of air entering the media pad at about 225 feet per minute at about room temperature is less than about 0.13 inches of water (e.g. about 0.0046965 psi).
The size of the apertures of the sheets of the media pad also defines in part the “evaporative efficiency” of the evaporative cooler having the media pad. The term “evaporative efficiency,” is also known as cooling or saturating efficiency or effectiveness. Evaporative efficiency is a rating of the performance of the evaporative cooler. Evaporative efficiency is conventionally calculated as follows:
Note, the term “dry bulb temperature” refers to the air temperature as measured by ordinary bare thermometers and the term “wet-bulb temperature” refers to thermometers whose bulbs are covered by wetted wicks exposed to rapidly moving air. See Watt et al., EVAPORATIVE AIR CONDITIONING HANDBOOK, 12-22 (Fairmont Press, Inc. 1997); see also ANSI/ASHRAE Standard No. 133-2001 titled “Method of Testing Direct Evaporative Air Coolers” by the American Society of Heating, Refrigeration and Air-Conditioning Engineers, Inc. bearing a designation of “2/02,” which are hereby incorporated by reference.
According to a preferred embodiment, the evaporative efficiency of the evaporative cooler having the flexible media pad(s) is greater than about 50 percent, suitably greater than about 60 percent. According to a preferred embodiment, the airflow across the media pad (e.g. about 3 to 4 flexible media pads of the evaporative cooler) is about 3000 cubic feet per minute.
According to a preferred embodiment, the wicking sheets of the media pad have a Klemm or capillary rise of greater than about 1.75 inches. The term “capillary rise” of water in paper as used in this disclosure means and includes the distance water rises in a strip of paper suspended vertically with its lower end immersed in water. The Klemm method is described in “Capillary Rise in Paper and Paperboard by the Klemm Method” SCAN testing method no. SCAN-P13: 64 (accepted June 1964), which is hereby incorporated by reference.
The capillary rise in paper sheet samples for various media pads were tested according to the Klemm method. The samples were each 6 inches tall. The samples were maintained in water for 10 minutes. The results of the capillary rise observed in the samples are shown in TABLE I.
As can be seen from TABLE 1, the flexible wicking paper has a greater Klemm or capillary rise than the rigid media paper(s).
Referring to
Referring further to
A water recirculation system 54 for recycling non-evaporated water back to pad 10 is shown in
According to a preferred embodiment as shown in
The evaporative cooling system may be placed outdoors as well as indoors according to any preferred or alternative embodiment. The evaporative cooling system is intended to be placed where there is an abundance of fresh air, and may be positioned adjacent to an open window or external door with additional openings on opposite sides of the room according to alternative embodiments. In this way, the evaporative cooling system may draw fresh air from the outside and be drawn through the pad, cooled, filtered and circulated through the room while the hot, stale air is forced out through the openings on the other side of the room.
The evaporative cooling system may be used in a variety of environments, including at least: industrial and commercial settings such as industrial plants, factories, assembly lines, warehouses, commercial kitchens, laundries, dry cleaners, greenhouses, confinement farming such as poultry ranches, hog, dairy, etc., retail outlets, garden centers, auto shops, hotels/resorts, etc., residential settings such as workshops, garages, kennels, horse stables, patios, barns, exercise areas, etc., outdoor settings such as loading docks, construction sites, athletic events, tented parties, sporting events, pools and patios, outdoor retail etc.
It is important to note that the construction and arrangement of the elements of the evaporative cooling system with flexible media as shown in the preferred and other exemplary embodiments is illustrative only. Although only a few embodiments of the present invention have been described in detail in this disclosure, those skilled in the art who review this disclosure will readily appreciate that many modifications are possible (e.g. variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, use of materials, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter disclosed. Accordingly, all such modifications are intended to be included within the scope of the present invention. The order or sequence of any process or method steps may be varied or re-sequenced according to alternative embodiments. Other substitutions, modifications, changes and omissions may be made in the design, operating conditions and arrangement of the preferred and other exemplary embodiments without departing from the spirit of the present invention as expressed in this disclosure.
This application is an application claiming the benefit under 35 USC 119(e) U.S. application No. 60/499,562, filed Sep. 2, 2003, incorporated herein by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 60499562 | Sep 2003 | US |
