Refrigeration – Structural installation – Geographic – e.g. – subterranean feature
Reexamination Certificate
2002-12-31
2004-06-22
Doerrler, William C. (Department: 3744)
Refrigeration
Structural installation
Geographic, e.g., subterranean feature
C062S527000
Reexamination Certificate
active
06751974
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an improved sub-surface, or in-ground/in-water, heat exchange means incorporating a sub-surface heating mode refrigerant flow regulating device and a cooling mode refrigerant flow regulating device by-pass means, so as to enable additional refrigerant flow around the regulating device in the cooling mode, for use in association with any direct expansion heating/cooling system, or partial geothermal heating/cooling system, utilizing sub-surface heat exchange elements as a primary or supplemental source of heat transfer.
Ground source/water source heat exchange systems typically utilize fluid-filled closed loops of tubing buried in the ground, or submerged in a body of water, so as to either absorb heat from, or to reject heat into, the naturally occurring geothermal mass and/or water surrounding the buried or submerged tubing. Water-source heating/cooling systems typically circulate, via a water pump, water, or water with anti-freeze, in plastic underground geothermal tubing so as to transfer heat to or from the ground, with a second heat exchange step utilizing a refrigerant to transfer heat to or from the water, and with a third heat exchange step utilizing an electric fan to transfer heat to or from the refrigerant to heat or cool interior air space.
Direct expansion ground source heat exchange systems, where the refrigerant transport lines are placed directly in the sub-surface ground and/or water, typically circulate a refrigerant fluid, such as R-22, in sub-surface refrigerant lines, typically comprised of copper tubing, to transfer heat to or from the sub-surface elements, and only require a second heat exchange step to transfer heat to or from the interior air space by means of an electric fan. Consequently, direct expansion systems are generally more efficient than water-source systems because of less heat exchange steps and because no water pump energy expenditure is required. Further, since copper is a better heat conductor than most plastics, and since the refrigerant fluid circulating within the copper tubing of a direct expansion system generally has a greater temperature differential with the surrounding ground than the water circulating within the plastic tubing of a water-source system, generally, less excavation and drilling is required, and installation costs are lower, with a direct expansion system than with a water-source system.
While most in-ground/in-water heat exchange designs are feasible, various improvements have been developed intended to enhance overall system operational efficiencies. Several such design improvements are taught in U.S. Pat. No. 5,623,986 to Wiggs, and in U.S. Pat. No. 5,816,314 to Wiggs, et al., the disclosures of which are incorporated herein by reference. These predecessor designs basically teach the utilization of a spiraled fluid supply line subjected to naturally surrounding geothermal temperatures, with a fully insulated fluid return line. However, since only the fluid return line is insulated, and since both the supply and return lines are all the same size, without a dedicated smaller sized refrigerant liquid/fluid transport line and a dedicated larger sized refrigerant vapor/fluid transport line so as to facilitate appropriate refrigerant supply and return capacity in a deep well (greater than 100 feet deep) direct expansion application, these predecessor designs are intended for a near-surface (within about 5 to 100 feet of the surface) direct expansion system application, when operating in a reverse cycle mode.
Other predecessor vertically oriented geothermal heat exchange designs are disclosed by U.S. Pat. No. 5,461,876 to Dressler, and by U.S. Pat. No. 4,741,388 to Kuriowa. Dressler's '876 patent teaches the utilization of several designs of an in-ground fluid supply and return line, with both the fluid and supply lines shown as being the same size, and not distinguished in the claims, but neglects to insulate either the fluid return line or the fluid supply line, thereby subjecting the heat gained or lost by the circulating fluid to a “short-circuiting” effect as the supply and return lines come into close proximity with one another at various heat transfer points. Dressler also discloses the alternative use of a pair of concentric tubes, with one tube being within the core of the other, with the inner tube surrounded by insulation or a vacuum. While this multiple concentric tube design reduces the “short-circuiting” effect, it is practically difficult to build and maintain and could be functionally cost-prohibitive, and it does not have a dedicated liquid line and a dedicated vapor line. Kuriowa's preceding '388 patent is similar to Dressler's subsequent spiral around a central line claim, but better, because Kuriowa insulates a portion of the return line, via surrounding it with insulation, thereby reducing the “short-circuiting” effect. However, Kuriowa does not have a dedicated liquid line and a dedicated vapor line. The lowermost fluid reservoir claimed by Kuriowa in all of his designs can work in a water-source geothermal system, but can be functionally impractical in a deep well direct expansion system, potentially resulting in system operational refrigerant charge imbalances, compressor oil collection/retention problems, accumulations of refrigerant vapor pockets due to the extra-large interior volume, and the like. Kuriowa also shows a concentric tube design preceding Dressler's, but it is subject to the same problems as Dressler's. Further, both Dressler's and Kuriowa's designs are impractical in a reverse-cycle, deep well, direct expansion system operation since neither of their primary designs provide for, or claim, an insulated smaller interior volume sized liquid line and an un-insulated larger interior volume sized vapor line, which are necessary to facilitate the system's most efficient operational refrigerant charge and the system's compressor's efficient refrigerant supply and return capacities.
Generally, a design which insulates the supply line from the return line and still permits both lines to retain natural geothermal heat exchange exposure, such as a thermally exposed, centrally insulated, geothermal heat exchange unit, as taught by Wiggs in U.S. patent application Ser. No. 10/127,517, which is incorporated herein by reference, would be preferable over non-insulated lines and over designs which insulate a portion of one sub-surface line. However, while Wiggs' '517 Application is an improvement over prior art, in a sub-surface soil application, it could still be subject to some minor short-circuiting effects and to some potentially adverse vapor formation in the liquid line at undesirable locations or times.
In direct expansion applications, supply and return refrigerant lines may be defined based upon whether they supply warmed refrigerant to the system's compressor and return hot refrigerant to the ground to be cooled, or based upon the designated direction of the hot vapor refrigerant leaving the system's compressor unit, which is the more common designation in the trade. For purposes of this present invention, the more common definition will be utilized. Hence, supply and return refrigerant lines are herein defined based upon whether, in the heating mode, warmed refrigerant vapor is being returned to the system's compressor, after acquiring heat from the sub-surface elements, in which event the larger interior diameter, sub-surface, vapor/fluid line is the return line and evaporator, and the smaller interior diameter, sub-surface, liquid/fluid line, operatively connected from the interior air handler to the sub-surface vapor line, is the supply line; or whether, in the cooling mode, hot refrigerant vapor is being supplied to the larger interior diameter, sub-surface, vapor fluid line from the system's compressor, in which event the larger interior diameter, sub-surface, vapor/fluid line is the supply line and condenser, and the smaller int
Doerrler William C.
Patterson Mark J.
Waddey & Patterson , P.C.
Walker Phillip E.
Zec Filip
LandOfFree
Sub-surface and optionally accessible direct expansion... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Sub-surface and optionally accessible direct expansion..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Sub-surface and optionally accessible direct expansion... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3328464