Air conditioning coil

Heat exchange – With impeller or conveyor moving exchange material – Mechanical gas pump

Reexamination Certificate

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Details

C165S124000, C165S145000, C165S146000

Reexamination Certificate

active

06276443

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of The Invention
This invention is directed to air conditioning coils and methods of their use.
2. Description of Related Art
Many prior art air conditioning systems require relatively large evaporator coils to achieve higher energy efficiencies. In certain systems it is desired to expose more face area of a coil to an air stream utilizing lower “face velocity,” but without enlarging coil height. The “face velocity” of an air conditioning coil is often defined as the total volummetric air flow passing through the coil divided by the total effective upstream side surface area of the coil. For example, the face velocity of a coil having a 2.0 square foot face area across which a 1200 cubic feet/minute air flow occurs would be 600 feet/minute. In various prior art systems refrigerant coils (such as conventional A-coils) used in the indoor sections of air conditioning equipment have a coil face velocity maintained within the 100-500 feet/minute velocity range. A coil face velocity above about 500 feet/minute may result in an unacceptable degree of condensate “blow through” or “blow off” and may raise the air pressure drop across the coil to an undesirable level.
Various prior art coils have two refrigerant coil slabs of a multi-row, multi-circuit construction for purposes of heat exchange efficiency. This multi-row/multi-circuit configuration may result in an air pressure drop across the coil that, as a practical matter, precludes the use in the coil of “enhanced” fins (i.e., fins of, for example, a lanced or louvered construction designed to increase the air-to-fin heat exchange efficiency). Typically fin spacing in prior art coils is between 10 to 22 fins/inch.
FIGS. 1A and 1B
show a prior art coil C as disclosed in U.S. Pat. No. 5,207,074 that has a single row/single circuit design with fin spacing in the range of about 16 fins/inch to about 22 fins/inch. Face velocity for such a coil is from about 100 feet/minute to about 200 feet/minute. By “single row/single circuit” is meant that there is a single row R of tubing, typically copper tubing, on each side of each coil and the tubing on each side is a single elongated piece with a plurality of U-turns extending through a plurality of fins F.
FIG. 2
shows another prior art single row/single circuit coil L as disclosed in U.S. Pat. 5,664,431 with single tubing rows T passing through a plurality of fins P. Fin spacing for such a coil may be 16-22 fins/inch and a typical face velocity of 300-450 feet/minute.
FIG. 3
shows prior art coils S, as disclosed in U.S. Pat. No. 5,284,027, each dual row/dual circuit tubing B on each side extending through a plurality of fins N, e.g. with fin spacing of 10-16 fins/inch and a typical face velocity of 170-250 feet/minute.
Another important consideration in coil design for heat pumps is the desire to maintain a certain volummetric relationship between an indoor heat exchanger and an outdoor heat exchanger. Using fewer rows of tubing reduces volummetric capacity and often a receiver is added to maintain the desired relationship (e.g. 0.8:1 to 1.2:1) between an indoor coil and an outdoor coil.
In many prior art coils each side or “slab” of the coil has the same number of rows of tubing and the same fin spacing.
There has long been a need for an effective and efficient air conditioning coil. There has long been a need for such a coil with increased capacity without significantly enlarging coil height. There has long been a need for such a coil with more exposed face area.
SUMMARY OF THE PRESENT INVENTION
The present invention discloses, in certain aspects, discloses an air conditioning coil with four slabs in a side-by-side double “A” configuration. Each of two outer slabs has two rows of tubing, e.g. (in a single circuit or in two circuits) with fin spacing between 10 and 16 fins/inch. In one aspect the fin spacing is 14 fins/inch. Each of two inner slabs has one row of tubing in a single circuit, e.g. with a fin spacing between 16 and 22 fins/inch. In one aspect fin spacing is 20 fins/inch.
In certain aspects the pressure drop across the two row slabs is within 10% of the pressure drop across the one-row slabs and, in certain preferred embodiments, the pressure drop is within 5%. This similarity in pressure drop provides relatively even air distribution across the coil face.
In certain aspects each of the slabs has tube spacing of one inch on center (“tube spacing” is the distance from the center of one tube to the center of another) that is about the same as the width of the fins (“fin width” is the distance from a fin leading edge to a fin trailing edge).
In certain embodiments, using twice the number of tubes in the two-row coils increases the coils volummetric capacity by about 100% (e.g. 40 tubes in the two-row slabs as compared to 20 tubes in the one-row slab).
In another embodiment of a coil according to the present invention in which there are two outer slabs and two inner slabs in a double “A” configuration, the outer slabs are two-row or three-row (in a single circuit or in multiple circuits) and the inner slabs are one-row or two-rows (in a single circuit or in multiple circuits), with fin spacing as described above.
What follows are some of, but not all, the objects of this invention. Objects other than the specific objects stated below, additional objects and purposes will be readily apparent to one of skill in this art who has the benefit of this invention's teachings and disclosures. It is, therefore, an object of at least certain preferred embodiments of the present invention to provide new, useful, unique, efficient and nonobvious air conditioning coils;
Such coils with multiple slabs with slabs having different members of tubing rows;
Such coils with slabs having a plurality of fins and different slabs having different fin spacing;
Such coils with relatively increased volummetric capacity without relatively increased height;
Such coils with different slabs (different numbers of rows and/or fin spacing) but with similar air pressure drop across the slabs;
Such slabs with tube spacing similar to fin width per row; and
Methods of using such coils.
Certain embodiments of this invention are not limited to any particular individual feature disclosed here, but include combinations of them distinguished from the prior art in their structures and functions. Features of the invention have been broadly described so that the detailed descriptions that follow may be better understood, and in order that the contributions of this invention to the arts may be better appreciated. There are, of course, additional aspects of the invention described below and which may be included in the subject matter of the claims to this invention. Those skilled in the art who have the benefit of this invention, its teachings, and suggestions will appreciate that the conceptions of this disclosure may be used as a creative basis for designing other structures, methods and systems for carrying out and practicing the present invention. The claims of this invention are to be read to include any legally equivalent devices or methods which do not depart from the spirit and scope of the present invention.
The present invention recognizes and addresses the previously-mentioned problems and long-felt needs and provides a solution to those problems and a satisfactory meeting of those needs in its various possible embodiments and equivalents thereof. To one of skill in this art who has the benefits of this invention's realizations, teachings, disclosures, and suggestions, other purposes and advantages will be appreciated from the following description of preferred embodiments, given for the purpose of disclosure, when taken in conjunction with the accompanying drawings. The detail in these descriptions is not intended to thwart this patent's object to claim this invention no matter how others may later disguise it by variations in form or additions of further improvements.


REFERENCES:
patent: 1846608 (1932-02-01), Phelps
patent: 2584442 (1952-02-01), Frie
patent: 35

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