Abstract:
A direct expansion/direct exchange (“DX”) geothermal heating/cooling system having a plurality of pin restrictors positioned in housing units at ground accessible locations. The pin restrictors are preferably located near the compressor unit and on the field side of the distributor. Refrigerant is substantially equally distributed by a distributor to substantially equally sized line sets in the DX system with multiple wells. The distributors are place in either horizontal or vertical inclinations with the pin restrictors situated on the field side of the distributor in each individual liquid refrigerant transport line. A cut-off ball valve is located within the liquid refrigerant transport line on each side of the respective pin restrictor housing units. A filter/dryer is place within the same liquid refrigerant transport line segment as the pin restrictor(s) with a refrigerant flow shut-off valve being situated on each side of the liquid line segment containing the filter/dryer and the distributor.

Description:
[0001]     This is a non-provisional application claiming priority based upon co-pending U.S. Patent Application Ser. No. 60/806,739 filed Jul. 7, 2006 entitled “Advanced Direct Exchange Geothermal Heating/Cooling System Design.” 
     
    
       [0002]     I, B. Ryland Wiggs, of Franklin, Tenn., have invented a new and useful “Advanced Direct Exchange Geothermal Heating/Cooling System Design”.  
         [0003]     A portion of the disclosure of this patent document contains material that is subject to copyright. The copyright owner has no objection to the authorized facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever.  
         [0004]     All patents and publications discussed herein are hereby incorporated by reference in their entirety.  
       BACKGROUND OF THE INVENTION  
       [0005]     The present invention relates to a geothermal direct exchange (“DX”) heating/cooling system, which is also commonly referred to as a “direct expansion” heating/cooling system, comprising various design improvements.  
         [0006]     Geothermal 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 fluid transport tubing. The tubing loop is extended to the surface and is then used to circulate one of the naturally warmed and naturally cooled fluid to an interior air heat exchange means.  
         [0007]     Common and older design geothermal water-source heating/cooling systems typically circulate, via a water pump, a fluid comprised of water, or water with anti-freeze, in plastic (typically polyethylene) underground geothermal tubing so as to transfer geothermal heat to or from the ground in a first heat exchange step. Via a second heat exchange step, a refrigerant heat pump system is utilized to transfer heat to or from the water. Finally, via a third heat exchange step, an interior air handler (comprised of finned tubing and a fan) is utilized to transfer heat to or from the refrigerant to heat or cool interior air space.  
         [0008]     Newer design geothermal DX heat exchange systems, where the refrigerant fluid transport lines are placed directly in the sub-surface ground and/or water, typically circulate a refrigerant fluid, such as R-22 or the like, in sub-surface refrigerant lines, typically comprised of copper tubing, to transfer geothermal heat to or from the sub-surface elements via a first heat exchange step. DX systems only require a second heat exchange step to transfer heat to or from the interior air space, typically by means of an interior air handler. Consequently, DX systems are generally more efficient than water-source systems because less heat exchange steps are required and because no water pump energy expenditure is necessary. Further, since copper is a better heat conductor than most plastics, and since the refrigerant fluid circulating within the copper tubing of a DX 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 DX system than with a water-source system.  
         [0009]     While most in-ground/in-water DX heat exchange designs are feasible, various improvements have been developed intended to enhance overall system operational efficiencies. Several such design improvements, particularly in direct expansion/direct exchange geothermal heat pump systems, are taught in U.S. Pat. No. 5,623,986 to Wiggs; in U.S. Pat. No. 5,816,314 to Wiggs, et al.; in U.S. Pat. No. 5,946,928 to Wiggs; and in U.S. Pat. No. 6,615,601 B1 to Wiggs, the disclosures of which are incorporated herein by reference. Such disclosures encompass both horizontally and vertically oriented sub-surface heat geothermal heat exchange means, utilizing historically conventional refrigerants, such as R-22, as well as utilizing a newer design of refrigerant identified as R-410A. R-410A is an HFC azeotropic mixture of HFC-32 and HFC-125.  
         [0010]     DX heating/cooling systems have several primary objectives. The first is to provide the greatest possible operational efficiencies. This directly translates into providing the lowest possible heating/cooling operational costs, as well as other advantages, such as, for example, materially assisting in reducing peaking concerns for utility companies. The second is to operate in an environmentally safe manner via the utilization of environmentally safe components and fluids.  
         [0011]     Historically, DX heating/cooling systems, even though more efficient than other conventional heating/cooling systems, have experienced practical limitations created by the relatively large surface land areas necessary to accommodate the sub-surface heat exchange tubing. For example, with R-22 systems, a typical land area of 500 square feet per ton of system design capacity was required in first generation designs to accommodate a shallow (within 10 feet of the surface) matrix of multiple, distributed, copper heat exchange tubes, or about one to two 50 foot to 100 foot (maximum) depth wells/boreholes per ton of system design capacity, spaced at least about 20 feet apart, were required. Such requisite surface areas effectively precluded system applications in many commercial and/or high density residential applications. An improvement over such predecessor designs was taught by Wiggs via the utilization of an R-410A refrigerant that operated at about a 40% higher pressure than R-22 systems, and that were able to efficiently operate at DWDX system depths, of about 300 to 350 feet per well/borehole.  
         [0012]     While a number of former DX system designs work, as a primary objective is to increase the efficiency and reliability of DX system designs, particularly in light of rapidly accelerating energy costs, extensive testing has demonstrated a number of design improvements that will enhance the efficiency and reliability of older DX system designs.  
         [0013]     It is an object of the subject inventions to improve upon earlier and former DX system technologies, so as to provide ultra-efficient, environmentally safe, DX system designs. The present inventions provide a solution to these preferable objectives, as hereinafter more fully described.  
       SUMMARY OF THE INVENTION  
       [0014]     The subject inventions primarily relate to DX system advantages when installed with DWDX system vertically oriented sub-surface geothermal heat exchange means, although various advantages are also present in near-surface (100 feet deep or less) DX system applications, particularly such as involving a trench system design, a pit system design, or any combination of the above. Thus, it is an object of the present inventions to further enhance and improve the efficiency and practical applicability of predecessor direct expansion/direct exchange (“DX”) geothermal heating/cooling systems. This is accomplished by means of providing the following:  
         [0015]     1. Providing pin restrictors, in housing units, at an accessible location, typically above-ground, for a DX system operating in the heating mode, where the pin restrictors are preferably located near the compressor unit, but on the field side of any distributor. Typical predecessor DX system designs utilized self-adjusting expansion valves in the heating mode, or utilized manually adjusted heating valves. The problem with self-adjusting heating valves in a DX system in the heating mode is that the refrigerant has to travel so far in the sub-surface environment, the automatic valve is constantly “hunting” for an optimum setting, resulting in rather continuous and inefficient swings in set points. The problem with a manually adjusted valve is that a precise optimum setting is a matter of luck, rather than design. Earlier pin restrictor designs by Wiggs taught the placement of the heating mode pin restrictors at or near the bottom of a deep well DX system design, or at the distal end of a mostly horizontal sub-surface refrigerant transport tubing design. While this design was a major improvement over predecessor technology, providing uniform refrigerant flow through systems with multiple combined wells/line sets, the ability to service or change the pin restrictor was cumbersome. Therefore, the placement of the pins in an above-ground location, in a manner so as to still insure uniform refrigerant flow through systems with multiple combined wells/line sets would be preferable. This is accomplished by means of equally distributing refrigerant flow through a distributor to equally sized line sets in a system with multiple wells, all while placing the distributors in at least one of an exactly horizontal and a vertical inclination, with the pin restrictors situated on the field side of the distributor in each individual liquid refrigerant transport line going to the subsurface geothermal heat transfer field below ground/water level. An individual liquid refrigerant transport line must be distributed to each pin restrictor. Further, it is advantageous to insure the pin restrictors are easily serviced by means of a cut-off ball valve located within the liquid refrigerant transport line on each side of respective pin restrictor housing units. Placing pin restrictors on each individual distributed liquid refrigerant transport line helps to insure an equal refrigerant flow rate and pressure into each respective geothermal heat exchange loop, and also provides a means to check for any restrictions in individual distributed heat exchange loops.  
         [0016]     Further, the use of a filter/dryer for refrigerant is a useful and common piece of equipment used in DX systems, as is well understood by those skilled in the art. However, historically in the DX field, filter/dryers have been placed within the compressor box itself. Thus, when the filter/dryer needs to be changed, the historical and common practice in the DX HVAC field has been to open the compressor box, re-claim all refrigerant the within the box, change the filter/dryer, and then replace the refrigerant that had been reclaimed. Typically, many compressor boxes in the DX field even have no isolation valves so as to limit refrigerant reclaiming to the refrigerant within the box. Thus, a design improvement, so as to materially facilitate servicing and reduce servicing time/expense, would be to place the filter/dryer within the same liquid refrigerant transport line segment as the pin restrictor(s), with a refrigerant flow shut-off valve being situated on each side of the liquid line segment containing the filter/dryer and the distributor (if there are more than one sub-surface liquid refrigerant transport lines).  
         [0017]     Since such a liquid line segment will be relatively heavy. Thus, so as not to incur a bent or crimped liquid refrigerant transport line via gravity over a period of time, it would be preferable for the field side cut-off valves to be situated on at least one of the ground and a solid support so as to carry the weight of the subject liquid line segment.  
         [0018]     Restrictions in at least one of a distributed geothermal heat exchange loop will be evidenced by a decreased refrigerant flow rate, by a higher temperature in the cooling mode and/or by a lower temperature in the heating mode. The cut-off valves on the other geothermal heat exchange loop(s) can be slightly engaged, a little at a time, until the loop temperatures of an operational system all evenly match. When the temperatures all match, the amount of restriction to the good geothermal heat exchange loop, via the degree of cut-off valve engagement, can be measured to determine the amount of restriction in the bad, restricted, heat exchange loop. If all multiple loops combined, with equal restrictions in each, provide the minimum necessary refrigerant flow rate for the particular DX system, the faulty restricted loop will not have to be replaced.  
         [0019]     2. The sizing of the heating mode pin restrictors for a DX system operating in the heating mode, with R-410A refrigerant, must be within the following size parameters, plus no more than 5%, and less no more than 17% of the area of each below identified pin diameter size in inches. If the pin size is increased by more than 5%, the sensible interior heat produced is lowered and the operational efficiency levels decrease. If the pin size is decreased by more than 17%, when one switches from the cooling mode to the heating mode at the end of a cooling season, the head pressure of the refrigerant may be excessively high, so as to shut the system off via its internal high pressure cut-off switch.  
         [0020]     ((or formula) (Calculation is 15% to 30% less than conventional R-22 chart sizes, with 15% being preferable to permit cooling to heating switch-over without too high of a head pressure.) (Plus, one must add additional refrigerant to offset the increased superheat caused by the smaller pin size, or premature compressor failure will result . . . this is taken into account in charging formula.))  
                                             *For A Single Line Set Trench System or DWDX System       (One Pin) - Heating Mode                Compressor Size   Pin Diameter Size In Inches                       13,400   0.033           16,000   0.036           18,000   0.038           19,000   0.039           20,000   0.040           20,100   0.040           21,000   0.042           22,000   0.043           23,000   0.044           24,000   0.045           25,000   0.046           26,000   0.047           26,800   0.048           27,000   0.048           28,000   0.049           29,000   0.050           30,000   0.051           31,000   0.051           32,000   0.052           33,000   0.053           34,000   0.053           35,000   0.054           36,000   0.054           37,000   0.055           38,000   0.056           39,000   0.056           40,000   0.057           41,000   0.057           42,000   0.058           43,000   0.058           44,000   0.059           45,000   0.059           46,000   0.059           47,000   0.060           48,000   0.060           49,000   0.060           50,000   0.061           51,000   0.061           52,000   0.062           53,000   0.062           54,000   0.063           55,000   0.063           56,000   0.064           57,000   0.064           58,000   0.065           59,000   0.065           60,000   0.065                      
 
         [0021]    
       
         
               
             
               
               
               
             
           
               
                   
               
               
                   
               
               
                 *For A Double Line Set Trench System or DWDX System (Two 
               
               
                 Pins . . . One Respectively Sized Pin In Each of the Two Pin Housing 
               
               
                 Sections of the Liquid Line Assembly Segment) - Heating Mode 
               
             
          
           
               
                   
                 Compressor Size 
                 Pin Diameter Size In Inches 
               
               
                   
                   
               
               
                   
                 26,000 
                 0.033 
               
               
                   
                 27,000 
                 0.034 
               
               
                   
                 28,000 
                 0.035 
               
               
                   
                 29,000 
                 0.035 
               
               
                   
                 30,000 
                 0.036 
               
               
                   
                 31,000 
                 0.036 
               
               
                   
                 32,000 
                 0.037 
               
               
                   
                 33,000 
                 0.037 
               
               
                   
                 34,000 
                 0.038 
               
               
                   
                 34,170 
                 0.038 
               
               
                   
                 35,000 
                 0.038 
               
               
                   
                 36,000 
                 0.038 
               
               
                   
                 37,000 
                 0.039 
               
               
                   
                 38,000 
                 0.040 
               
               
                   
                 39,000 
                 0.040 
               
               
                   
                 40,000 
                 0.040 
               
               
                   
                 41,000 
                 0.041 
               
               
                   
                 42,000 
                 0.041 
               
               
                   
                 43,000 
                 0.041 
               
               
                   
                 44,000 
                 0.042 
               
               
                   
                 45,000 
                 0.042 
               
               
                   
                 46,000 
                 0.042 
               
               
                   
                 47,000 
                 0.042 
               
               
                   
                 48,000 
                 0.042 
               
               
                   
                 49,000 
                 0.043 
               
               
                   
                 50,000 
                 0.043 
               
               
                   
                 51,000 
                 0.043 
               
               
                   
                 52,000 
                 0.044 
               
               
                   
                 53,000 
                 0.044 
               
               
                   
                 54,000 
                 0.044 
               
               
                   
                 55,000 
                 0.045 
               
               
                   
                 56,000 
                 0.045 
               
               
                   
                 57,000 
                 0.045 
               
               
                   
                 58,000 
                 0.046 
               
               
                   
                 59,000 
                 0.046 
               
               
                   
                 60,000 
                 0.046 
               
               
                   
                   
               
             
          
         
       
     
         [0022]    
       
         
               
             
               
               
               
             
           
               
                   
               
               
                   
               
               
                 *For A Triple Line Set Trench System or DWDX System (Three 
               
               
                 Pins . . . One Respectively Sized Pin In Each of the Three Pin Housing 
               
               
                 Sections of the Liquid Line Assembly Segment) - Heating Mode 
               
             
          
           
               
                   
                 Compressor Size 
                 Pin Diameter Size In Inches 
               
               
                   
                   
               
               
                   
                 54,000 
                 0.036 
               
               
                   
                 55,000 
                 0.036 
               
               
                   
                 56,000 
                 0.037 
               
               
                   
                 57,000 
                 0.037 
               
               
                   
                 58,000 
                 0.037 
               
               
                   
                 59,000 
                 0.038 
               
               
                   
                 60,000 
                 0.038 
               
               
                   
                 83,000 
                 0.044 
               
               
                   
                   
               
             
          
         
       
     
         [0023]    
       
         
               
             
               
               
               
             
           
               
                   
               
               
                   
               
               
                 *For A Quadruple Line Set Trench System or DWDX System (Four 
               
               
                 Pins . . . One Respectively Sized Pin In Each of the Four Pin Housing 
               
               
                 Sections of the Liquid Line Assembly Segment) - Heating Mode 
               
             
          
           
               
                   
                 Compressor Size 
                 Pin Size 
               
               
                   
                   
               
               
                   
                 83,000 
                 0.038 
               
               
                   
                   
               
             
          
         
       
     
         [0024]     In the alternative, the following formula may be used to determine the correct heating mode pin size:  
         [0025]     For a 13,400 BTU through a 44,000 BTU compressor size (not air handler size and not system design size, but the actual size of the compressor in the compressor unit/box), multiply the compressor size in thousandths by 0.000065. Match the resulting number, which will be the area of the orifice, to the closest pin size diameter. For example, if the system has a 21,000 BTU compressor, multiple 21 by 0.000065, which equals a 0.001365 area, which is nearest to a 0.042 pin restrictor size diameter.  
         [0026]     For a 45,000 BTU through a 60,000 BTU compressor size (not air handler size and not system design size, but the actual size of the compressor in the compressor unit/box), multiply the compressor size in thousandths by 0.000058. Match the resulting number, which will be the area of the orifice, to the closest pin size diameter. For example, if the system has a 54,000 BTU compressor, multiple 54 by 0.000058, which equals a 0.003132 area, which is nearest to a 0.063 pin restrictor size diameter.  
         [0027]     Regarding the above formula, when one wishes to use two, three, or more pin restrictors for one system, in a situation where the heat exchange tubing is distributed into two or more geothermal heat exchange sub-surface fields, the final calculated area needs to be divided by 2, 3, etc., and then matched to the nearest pin size used.  
         [0028]     3. Although in a typically cooling to heating season period, the ground, which has been absorbing rejected heat all summer, will typically cool enough to permit instant DX system heating mode operation with only a properly sized heating mode pin restrictor, if the seasonal change is extremely abrupt and fast, a pressure regulated heating mode refrigerant by-pass vale within a heating mode by-pass line around the heating mode pin restrictor may be necessary so as to permit instant system heating mode operation without the system tripping off via its safety high pressure cut off switch. To accomplish this optional heating mode protective means, one should preferably add a heating mode by-pass pressure regulated valve, also referred to as an automatic expansion valve (“AXV”), so as to assist transition from the cooling mode to the heating mode so that the valve opens to an interior diameter of at least the size of the actual BTU size, in thousandths, of the compressor in the compressor unit/box multiplied by 0.00008, with no less than multiplied by 0.00006, and with preferably no more than multiplied by 0.00016, to be opened when the refrigerant head pressure is 375 psi (plus or minus 5 psi) or greater, and to be closed when the refrigerant head pressure is below 375 psi (plus or minus 5 psi). Match the resulting number, which will be the area of the orifice, to the closest pin size diameter if to be measured in pin restrictor sizing. The higher the refrigerant pressure, the greater the opening in the valve. The valve should begin to open at an 0.00008, and should be no larger than 0.00016. When the DX system refrigerant head pressure in the heating mode is less than 375 psi, the valve will be fully closed, thereby forcing the refrigerant flow through the properly designed pin restrictor orifice opening only.  
         [0029]     4. The cooling mode TXV by-pass pin restrictor size must be within the following size parameters:  
                                                   COMPRESSOR BTU SIZE               (NOT TS MODEL SIZE)   PIN SIZE IN INCHES                           16,000   .044           18,000   .048           21,000   .050           24,000   .054           25,000   .055           26,000   .056           29,000   .059           32,000   .062           33,000   .062           34,000   .062           35,000   .063           36,000   .064           38,000   .065           42,000   .069           44,000   .070           48,000   .073           50,000   .075           51,000   .076           54,000   .078           55,000   .079           56,000   .080           57,000   .081           60,000   .083           83,000   .098                      
 
         [0030]     In the alternative, the following formula may be used to determine the correct TXV by-pass pin size:  
         [0031]     For a 21,000 BTU through a 32,000 BTU compressor size (not air handler size and not system design size, but the actual size of the compressor in the compressor unit/box), multiply the compressor size in thousandths by 0.000095. Match the resulting number, which will be the area of the orifice, to the closest pin size diameter. For example, if the system has a 21,000 BTU compressor, multiple 21 by 0.000095, which equals a 0.001995 area, which is nearest to a 0.050 pin restrictor size diameter.  
         [0032]     For a 33,000 BTU compressor size (not air handler size and not system design size, but the actual size of the compressor in the compressor unit/box), multiply the compressor size in thousandths by 0.000091. Match the resulting number, which will be the area of the orifice, to the closest pin size diameter. For example, if the system has a 33,000 BTU compressor, multiple 33 by 0.000091, which equals a 0.0030 area, which is nearest to a 0.062 pin restrictor size diameter.  
         [0033]     For a 34,000 BTU through a 55,000 BTU compressor size (not air handler size and not system design size, but the actual size of the compressor in the compressor unit/box), multiply the compressor size in thousandths by 0.000088. Match the resulting number, which will be the area of the orifice, to the closest pin size diameter. For example, if the system has a 48,000 BTU compressor, multiple 48 by 0.000088, which equals a 0.004224 area, which is nearest to a 0.073 pin restrictor size diameter.  
         [0034]     For a 56,000 BTU through a 83,000 BTU compressor size (not air handler size and not system design size, but the actual size of the compressor in the compressor unit/box), multiply the compressor size in thousandths by 0.00009. Match the resulting number, which will be the area of the orifice, to the closest pin size diameter. For example, if the system has a 60,000 BTU compressor, multiple 60 by 0.00009, which equals a 0.0054 area, which is nearest to a 0.083 pin restrictor size diameter.  
         [0035]     Regarding the above formulas, when one wishes to use two, three, or more pin restrictors for one system, in a situation where the heat exchange tubing is distributed into two or more air handlers, for example, the final calculated area needs to be divided by 2, 3, etc., and then matched to the nearest pin size used.  
         [0036]     5. Add a cooling mode TXV by-pass pressure regulated valve, also referred to as an automatic expansion valve (“AXV”), so as to assist transition from the heating mode to the cooling mode in a DX system.  
         [0037]     Add a cooling mode by-pass pressure regulated valve, also referred to as an automatic expansion valve (“AXV”), so as to assist transition from the heating mode to the cooling mode so that the valve opens to an interior diameter of at least the size of the actual BTU size, in thousandths, of the compressor in the compressor unit/box multiplied by 0.00009, with no less than multiplied by 0.00009, and with preferably no more than multiplied by 0.00018, to be opened when the refrigerant suction pressure is 85 psi (plus or minus 5 psi) or less, and to be closed when the refrigerant suction pressure is above 85 psi (plus or minus 5 psi). Match the resulting number, which will be the area of the orifice, to the closest pin size diameter if to be measured in pin restrictor sizing. The lower the refrigerant pressure, the greater the opening in the valve.  
         [0038]     Alternately, although not as precise as individually tailored by-pass valves for each respective compressor size, a one size fits all valve opening to the actual BTU size, in thousandths, of a five ton compressor in the compressor unit/box multiplied by 0.00009, with no less than multiplied by 0.00009, and with preferably no more than multiplied by 0.00018, to be opened when the refrigerant suction pressure is 85 psi (plus or minus 5 psi) or less, and to be closed when the refrigerant suction pressure is above 85 psi (plus or minus 5 psi), may be used for systems with 1 through 5 ton compressor units.  
         [0039]     The AXV should be an external equalized valve, with a capillary tube extended from the valve to the low pressure vapor line exiting the air handler. The valve should preferably be an adjustable type valve that can be set to shut off at any pressure between 40 psi and 100 psi., with an 85 psi shut off point being preferable for a DX system application.  
         [0040]     6. For maximum cooling capacity and humidity removal, the receiver size must be sized at 1 pound for every 40 feet of ⅜ inch O.D. liquid line depth within a DWDX system design, or the equivalent thereof when other line set sizes are utilized, exclusive of the trenched line(s) to/from the well(s) and the compressor unit.  
         [0041]     For maximum cooling operational efficiencies and minimum vertical well refrigerant pressure drop, the receiver size must be sized at 1 pound for every 50 feet of ⅜ inch O.D. liquid line depth within a DWDX system design, or the equivalent thereof when other line set sizes are utilized, exclusive of the trenched line(s) to/from the well(s) and the compressor unit, and exclusive of any other DX system refrigerant containment components.  
         [0042]     7. Differing air handler manufacturers utilize differing finned tubing lengths per ton of size design capacity. However, most air handler manufacturers utilize finned tubing with 12 to 14 fins per inch length. Since differing manufacturers utilize differing lengths of tubing per ton of design capacity, it is inefficient to prescribe a certain tonnage air handler to be used with a particular DX system BTU compressor size. Further, to optimize DX system efficiencies, testing has shown it is impractical to match a 3 ton compressor with a 3 ton air handler, as most all predecessor conventional system designs call for. Testing has shown that in order to optimize the efficiency of a DX system design, the air handler must be sized to 120% of the maximum system design load and must have 60 feet per ton, plus or minus 5 feet, of finned 3/8 inch O.D. interior heat exchange tubing. 55 to 60 feet is preferable in heating mode. 60 to 65 feet is preferable in cooling mode.  
         [0043]     8. The DX system charging formula, using R-410A refrigerant (all known predecessor DX systems sold operate on an R-22, or similar, refrigerant with significantly lower operating pressures than R-410A) for a DWDX system, with a preferred sub-surface ⅜ inch O.D. liquid refrigerant grade transport line in the well/borehole, with a 0.032 inch wall thickness, and a sub-surface ¾ inch O.D., or larger, vapor refrigerant grade geothermal heat exchange transport line in the well/borehole, is calculated by adding the sum of the following:  
         [0044]     A. Total depth of the ⅜ inch O.D. liquid line in well times 0.0375 pounds  
         [0045]     B. 50% of total length of finned ⅜ inch O.D. tubing in air handler multiplied by 0.0375 pounds.  
         [0046]     C. Compressor unit/box content of liquid refrigerant. For an ETA system, for a 1.5 to a 4 ton system, add 1.5 pounds. For a 4.1 to a 5 ton system, add 2 pounds.  
         [0047]     D. Add the amount of liquid refrigerant contained in the system&#39;s filter/dryer (for example, a Parker Bi-Directional R-410A Heat Pump Filter/Dryer Model BF164-XF holds about 0.761875 pounds), exclusive of the filter/dryer in the compressor box, which has already been taken into account in the compressor unit/box content.  
         [0048]     E. Add the amount of liquid refrigerant in all liquid line ball cut-off valves (typically about 0.05 pounds), exclusive of the ball cut-off valves in the compressor box, which have already been taken into account in the compressor unit/box content.  
         [0049]     F. Measure the total liquid transport line length between the top of the well/borehole and the compressor unit/box and multiply by the full liquid weight content of the line in pounds. For example, multiply by 0.0375 pounds if it is a ⅜ inch O.D. line, but multiply by 0.06875 if it is a ½ inch O.D line.  
         [0050]     G. Measure the total liquid transport line length between the air handler and the compressor unit/box and multiply by the full liquid weight content of the line in pounds. For example, multiply by 0.0375 pounds if it is a ⅜ inch O.D. line, but multiply by 0.06875 if it is a ½ inch O.D line.  
         [0051]     H. For a cooling mode charge, add an additional 1 pound of refrigerant for every 40 feet of ⅜ inch O.D. refrigerant grade liquid line in the well for maximum system operational capacity and humidity removal. If humidity removal is not a concern, add an additional 1 pound of refrigerant for every 50 feet of ⅜ inch O.D. refrigerant grade liquid line in the well for maximum efficiency.  
         [0052]     I. If the system is designed to operate in a reverse-cycle mode (heating and cooling), the system must have a liquid line receiver that holds the preferred charge differential between the heating mode and the cooling mode. Additionally, the receiver will have some constant amount of liquid content in its bottom, regardless of the system operational mode, which constant amount of refrigerant, in pounds, must be added. For example, a typically well designed receiver usually always holds 0.75 pounds, regardless of whether operating in the heating or the cooling mode.  
         [0053]     Prior DX system designs with receivers either failed to specify a receiver with only one refrigerant entrance and exit and/or failed to specify the amount of refrigerant the receiver was to hold and/or referenced a receiver percentage content equal to some uniform percentage (such as 40% for example) of the total system charge, typically all without defining how to determine the exact system charge. Consequently, prior DX receiver designs have been generally useless. Testing has shown that the receiver content must be as hereinabove described, with only one refrigerant entrance and exit, for a reverse-cycle DX system to operate at one of its optimum capacity and efficiency. No known person has heretofore discovered or taught the receiver capacity in a DX system is dependent upon well/borehole depth with specified and certain liquid refrigerant transport line sizes.  
         [0054]     J. If the system is designed to operate in the heating mode with a heating mode pin expansion device installed, the weight, in pounds, of the liquid content of the pin restrictor housing design must be added to the total.  
         [0055]     The total of the appropriate above sums will equal the correct system charge.  
         [0056]     To determine the optimum charge in DX systems utilizing other than ⅜ inch O.D. liquid refrigerant transport lines and ¾ inch O.D. vapor refrigerant transport lines, the charge should preferably be determined by the above formula, except the equivalent refrigerant content of the actual interior volume of the liquid refrigerant transport line used must be matched to the interior volume of a ⅜ O.D. liquid refrigerant transport line as per the above formula. For example, if multiple liquid refrigerant transport lines of a smaller interior diameter were utilized than that of a ⅜ inch O.D. refrigerant grade copper tube, then the content of all multiple smaller lines must match that of the content of a system designed with at least one of one and multiple ⅜ inch O.D. refrigerant grade copper tube(s). As another example, if a larger liquid refrigerant transport line was used than that of a ⅜ inch O.D. refrigerant grade copper tube, then the interior content of the larger tube must match that of the content of a system designed with at least one of one and multiple ⅜ inch O.D. refrigerant grade copper tube(s).  
         [0057]     9. Place a rubber mat over the top of all DX system geothermal heat exchange wells in lightening prone areas. Additionally, in areas prone to lightening strikes, all copper tubing within trenches between wells and compressor units should preferably be insulated with plastic or rubber material that is not electrically conductive, such as expanded foam polyethylene and/or neoprene. This will assist in mitigating lightening strikes in lightening prone areas, such as Florida.  
         [0058]     Copper tubing well installation spools, with pre-assembled line sets for DX system field loop installations, should preferably have at least a 24 inch wide holding tube diameter, with both insulated and un-insulated refrigerant transport lines on the same holding spool, with spiraled fiber tape to keep the lines together. The holding spool should preferably have sides extending past the outer layer of the refrigerant transport lines, but with a four foot, or less, diameter so as to facilitate shipping on a four foot wide pallet. Prior to assembly, the line set, with a cementitious grout-filled (preferably Grout 111) “Torpedo” unit surrounding the liquid refrigerant transport line U bend and the liquid refrigerant transport line coupling to the vapor refrigerant transport line at the bottom, should be evacuated of air with a vacuum pump (typically an electrically operated pump) to at least a 250 micron vacuum, and then charged with a dry nitrogen holding charge of 50 pounds, or the like, for shipment and installation. Pulling the vacuum and charging with dry nitrogen is accomplished via sealing one of the liquid and vapor refrigerant transport lines shut and installing a schraeder valve on the other for gauge set attachment and hook up to the vacuum pump and then to the pressurized bottle of dry nitrogen, as is well understood by those skilled in the art.  
         [0059]     The 250 micron vacuum will insure there are no leaks, and the 50 pound holding charge will insure no leaks have occurred during either shipment or installation. Both pulling the vacuum and inserting the holding charge of dry nitrogen are effected by means of capping one of the ends of the liquid refrigerant transport line and vapor refrigerant transport lines, and placing a schraeder valve (a schraeder valve is well understood by those skilled in the art) in the other for refrigeration gauge set attachment (refrigeration gauges are well understood by those skilled in the art). This procedure comprises a significant time saving and efficiency improvement over the historical and traditional method of installing sub-surface heat exchange tubing in a DX system, where the tubing is installed, sealed, and pressure tested prior to pulling a vacuum and charging, which is more time consuming and is not as trustworthy as initially pulling a vacuum. Pulling a vacuum cannot be done to 250 microns in a DX system if there is a leak, whereas a pressure test could take hours or days to reveal a very slight leak. A Torpedo unit is comprised of a tube with a rounded nose, which tube contains refrigerant transport tubing, the lower liquid line U bend, and a cementitious grout fill material, preferably comprised of Grout 111, which Grout 111 is shrink and crack resistant, with a very high 1.4 BTUs/Ft.Hr. Degrees F heat transfer rate. The rounded nose on the Torpedo unit prevents hang-ups on rugged well/borehole sides and/or ledges as the copper refrigerant transport tubing line set is lowered into the well/borehole.  
         [0060]     The pre-assembled line set, comprised of an insulated smaller diameter liquid refrigerant transport line and an un-insulated larger diameter vapor refrigerant transport line, should preferably be surrounded by a spiraled fiber tape, or the like, so as to keep the refrigerant transport lines together as they are lowered into the well/borehole. The tape  70  must be spiraled at least once every eight to twelve inches to be effective.  
         [0061]     11. A near-surface, but sub-surface, DX trench geothermal heat exchange system should preferably be comprised of equal lengths of a smaller diameter un-insulated refrigerant transport tubing and of a larger diameter un-insulated refrigerant transport tubing, and should preferably be installed with at least 100 feet of refrigerant transport tubing per ton of the maximum heating/cooling BTU load design, as per ACCA Manuel J or the like, where 12,000 BTUs equal one ton of heating/cooling capacity. However, 120 feet per ton is a preferred length to assist in insuring optimum system operational efficiencies.  
         [0062]     In such a DX trench system, one liquid refrigerant transport line would be coupled to one vapor refrigerant transport line at the distal end of the sub-surface heat exchange loop, with the liquid line making at least a 6 inch vertically and downwardly oriented U bend prior to coupling to the vapor line at the at least 6 inch higher elevation. The U bend should be at the lowest point of the entire heat exchange loop, and the vapor line must be one of at least horizontally oriented and downwardly sloped (downwardly sloped being preferred) to the U bend. Preferably, such heat exchange loops would not exceed 360 feet in length per loop.  
         [0063]     In such a DX trench system, the liquid refrigerant transport line would preferably be comprised of one 120 foot long ⅜ inch O.D. refrigerant grade copper tube, or the like, per ton of system design capacity, with a maximum 360 foot distance per liquid line segment in each respective loop.  
         [0064]     In such a DX trench system, the vapor refrigerant transport line would preferably be comprised of one 120 foot long ¾ inch O.D. refrigerant grade copper tube, or the like, per ton of system design capacity, with a maximum 360 foot distance per vapor line segment in each respective loop.  
         [0065]     In such a DX trench system, neither the vapor refrigerant transport line used for subsurface heat exchange, nor the liquid refrigerant transport line used for subsurface heat exchange, would be insulated, and the respective vapor line and liquid line, except for being coupled together at the distal end of the loop, would be separated by at least 20 feet, with a 30 foot separation being preferable where land area permits. When the vapor line and liquid line near one another for connection to the DX system compressor unit, each line should preferably be fully insulated, with a closed cell insulation (such as expanded polyethylene and/or neoprene, or the like) when they are at least within 20 feet of one another.  
         [0066]     In such a near-surface trench system application, when the design capacity calls for more than one 360 foot long loop, multiple sub-surface geothermal heat exchange loops, comprised of larger diameter vapor lines coupled at their respective distal ends to respective smaller diameter liquid lines would preferably be joined together by means of a vapor line distributor and a liquid line distributor for refrigerant transportation to the compressor unit. Here, as in a single loop application, insulation would preferably surround all sub-surface tubing within twenty feet of one another.  
         [0067]     12. A DX system may be utilized where the sub-surface heat exchange tubing is installed under water. When in moving water, such as at least one of a stream, a creek, a river, and a tidal area, and the like, a DX system with refrigerant transport heat exchange tubing in the moving water needs only forty feet per ton to operate at design system tonnage capacity (as per ACCA Manuel J or the like) with sixty feet per ton being preferred with a design safety margin. The heat exchange tubing, should be exposed to the water via at least one of an extended line, a looped, coiled, and largely spread apart line, a looped, coiled, and modestly spread apart line, a series of U bends, and the like, always with the heat exchange line at a downwardly sloped elevation to a connecting liquid line, by means of a coupling, at the bottom/distal end. The refrigerant transport lines/tubing would typically be insulated, after exiting the water, on the way to the compressor unit.  
         [0068]     The heat exchange tubing should preferably be comprised of ¾ inch O.D. refrigerant grade copper tubing, or the like, for use in conjunction with up to a 30,000 BTU compressor. The heat exchange tubing should preferably be comprised of ⅞ inch O.D. refrigerant grade copper tubing, or the like, for use in conjunction with a 31,000 BTU compressor up to an 83,000 BTU compressor. When smaller heat exchange tubing is used, the interior diameter of the smaller lines should preferably approximately equal the interior diameter of the respective ¾ inch O.D. and ⅞ inch O.D. lines as described in this paragraph with the varying compressor sizes.  
         [0069]     The connecting liquid line, which will travel from the distal and lowest end of the larger heat exchange tubing back to the system&#39;s compressor unit, should be comprised of ⅜ inch O.D. refrigerant grade copper tubing, or the like, for use in conjunction with up to a 30,000 BTU compressor. The connecting liquid line, which will travel from the distal and lowest end of the larger heat exchange tubing back to the system&#39;s compressor unit, should be comprised of ½ inch O.D. refrigerant grade copper tubing, or the like, for use in conjunction with a 31,000 BTU compressor up to an 83,000 BTU compressor. When smaller liquid line refrigerant transport tubing is used, the interior diameter of the smaller lines should preferably approximately equal the interior diameter of the respective ⅜ inch O.D. and ½ inch O.D. lines as described in this paragraph with the varying compressor sizes.  
         [0070]     When in salt water and/or in water that is at least one of corrosive and abrasive to copper or other refrigerant transport tubing, the refrigerant transport tubing must be situated within a protective encasement, such as at least one of Grout 111, titanium, polyethylene, and a non-corrosive fluid filled pipe, and the like.  
         [0071]     Alternately, the heat exchange tubing could be installed with finned tubing within a containment box made of a resistant material, such as at least one of titanium, Grout 111, polyethylene, and the like, to prevent micro-organism damage. Micro-organisms in seawater eat stainless steel. Preferably, such a containment box would be filled with a non-corrosive fluid, such as pure water or the like, and would have an expanded top and bottom to facilitate the collection and transfer of heat to the surrounding water (the warmest water would naturally rise to the top of the containment box and the coolest water would naturally fall to the bottom of the containment box in both the cooling mode and in the heating mode, all while the heat transporting refrigerant would be traveling from the top to the bottom in the cooling mode, and from the bottom to the top in the heating mode, thereby providing maximum heat transfer ability and efficiency.  
         [0072]     While submerged heat exchange tubing may be placed within a protective polyethylene covering, preferably one of a protective titanium or Grout 111 covering would be utilized, as polyethylene has a relatively poor heat transfer rate of only 0.225 BTUs/Ft. Hr. degrees F.  
         [0073]     13. A DX system may be utilized where the sub-surface heat exchange tubing is installed under water. When in moving water, such as at least one of a stream, a creek, a river, and a tidal area, or the like, a DX system with refrigerant transport heat exchange tubing in moving water needs only 40 feet per ton to operate at design system tonnage capacity, with 60 feet per ton being preferred with a design safety margin. The heat exchange tubing should be exposed to the water via at least one of an extended line, a looped line, a coiled line, and a spiraled, spread apart, and a looped line, always with the heat exchange line at a downwardly sloped elevation to a connecting liquid line at the bottom/distal end.  
         [0074]     The heat exchange tubing should preferably be comprised of ¾ inch O.D. refrigerant grade copper tubing, or the like, for use in conjunction with up to a 30,000 BTU compressor. The heat exchange tubing should preferably be comprised of ⅞ inch O.D. refrigerant grade copper tubing, or the like, for use in conjunction with a 31,000 BTU compressor up to an 83,000 BTU compressor.  
         [0075]     The connecting liquid line, which will travel from the distal and lowest end of the larger heat exchange tubing back to the system&#39;s compressor unit, should be comprised of ⅜ inch O.D. refrigerant grade copper tubing, or the like, for use in conjunction with up to a 30,000 BTU compressor. The connecting liquid line, which will travel from the distal and lowest end of the larger heat exchange tubing back to the system&#39;s compressor unit, should be comprised of ½ inch O.D. refrigerant grade copper tubing, or the like, for use in conjunction with a 31,000 BTU compressor up to an 83,000 BTU compressor.  
         [0076]     Alternately, the heat exchange tubing could be installed with finned tubing within a containment box made of a corrosive-resistant material, such as at least one of titanium, Grout 111, polyethylene, and the like, to prevent damage from corrosive elements in the surrounding water and to prevent damage form micro-organisms living in the surrounding water. For example, some micro-organisms in seawater eat stainless steel. Therefore, the containment box would not be comprised of stainless steel in seawater. Preferably, such a containment box would be filled with a non-corrosive fluid, such as pure water or the like, and would have an expanded top portion and an expanded bottom potion to facilitate the collection and transfer of heat to the surrounding water (the warmest water would naturally rise to the top of the containment box and the coolest water would naturally fall to the bottom of the containment box in both the cooling mode and in the heating mode, all while the heat transporting refrigerant (within the finned refrigerant heat transport tubing within the containment box) would be traveling from the top portion of the finned tubing to the bottom portion of the finned tubing within the containment box in the cooling mode, and from the bottom portion of the finned tubing to the top portion of the finned tubing in the heating mode, thereby providing maximum heat transfer ability.  
         [0077]     While submerged heat exchange tubing may be placed within a protective polyethylene containment box covering, preferably a containment box comprised of at least one of titanium and Grout 111 would be utilized, as polyethylene has a relatively poor heat transfer rate of only 0.225 BTUs/Ft. Hr. degrees F. However, protective piping, within which both the un-fined vapor refrigerant transport line and the liquid refrigerant transport line (traveling to and from the heat exchange tubing, with fins, within the containment box) may be placed, may be comprised of a polyethylene pipe, or the like, as heat transfer in the protective pipe around the refrigerant transport lines to/from the containment box is not of critical importance. Insulation would preferably be placed around all refrigerant transport tubing situated above the water.  
         [0078]     When in salt water and/or in water that is at least one of corrosive and abrasive to copper or other refrigerant transport tubing, the refrigerant transport tubing must be situated within a protective encasement, such as at least one of Grout 111, titanium, polyethylene, and a non-corrosive fluid filled pipe, and the like. The protective encasement may be comprised of a shell. In the alternative, the protective encasement may be comprised of a solid material, such as Grout 111. Grout 111 is highly heat conductive (1.4 BTUs/Ft.Hr. Degree F.), weighs about 18.5 pounds per gallon, is virtually water impervious, and cures as a solid cementitious grout. A Grout 111 protective encasement will, therefore, act as both a good heat transfer agent and as an anchor for the larger diameter, downwardly sloping, heat exchange refrigerant vapor transport tubing, coupled at the lower distal end to the smaller diameter liquid refrigerant transport tubing. The portions of the refrigerant transport tubing above the water would be insulated.  
         [0079]     14. How to offset water buoyancy in a DWDX system installation. When water is encountered, the buoyancy of the insulated liquid line in a DX system will require the addition of additional adding weight to offset the buoyancy. The weight needed to offset the buoyancy of a ⅜ inch O.D. liquid refrigerant transport line comprised of copper, surrounded by a closed cell type insulation with a ¾ inch thick wall, together with a ¾ inch O.D. un-insulated vapor refrigerant transport line, being dropped into a water-filled well/borehole, is about 1.5 pounds per foot of depth. Preferably steel, or the like, rods are used to add weight in a DX system. Weight may be added via taping/tying maximum five foot segments of maximum 2 inch diameter steel tubing (2 inch diameter weighs 10.68 pounds per foot . . . 1.75 inch diameter weighs 8.18 pounds per foot . . . 1.5 inch diameter weighs 6.01 pounds per foot) or smaller re-bar, or the like, to the line set as needed. Prior to attachment, the steel, or the like, tubing should preferably be wrapped in a protective wrapping, such as shrink wrap, tape, or the like, so as to protect the copper refrigerant transport tubing. The taping/tying of the maximum five foot long segment to the copper tubing should be done at the top and at the bottom of the segment only, so as to only place a minimum of heat transfer inhibiting tape, or the like, around the vapor refrigerant transport line used for geothermal heat transfer, and so as to permit some flexibility between the segments during installation into a well/borehole that may not be perfectly straight, so as to avoid jamming.  
         [0080]     DX systems utilizing a ⅜ inch O.D., or less, liquid refrigerant line, and utilizing a ¾ inch O.D., or less vapor refrigerant line, typically require 4.5 inch to 6 inch diameter wells/boreholes, so as to provide enough room to easily insert the refrigerant transport lines, as well as the insulation surrounding the liquid line. A trimme tube is typically used to fill the annular space remaining within the well with a grout. The trimme tube is typically close to the same weight as water, and has an open lower distal end. Thus, the trimme tube fills with water as the rest of the closed loop refrigerant tubing and insulation are all inserted into the water filled well/borehole.  
         [0081]     Add as many segments of steel tubing as necessary to offset the buoyancy. However, there must not be a vertical gap between the segments being added. If a vertical gap exists, which is historically permissible when plastic polyethylene pipe is used to transport water as a geothermal heat exchange fluid, the soft copper refrigerant transport tubing in a DX system application could be crimped/damaged during installation. Thus, in a DX system application, it is critical that the segments must be placed directly above one another, or slightly overlapped. A maximum of 5 foot long segments, although 4 foot long segments are preferred, should be used in a DX system application so as to avoid damaging the copper refrigerant transport tubing, and so as to avoid jamming during the insertion, when the well/borehole is not perfectly straight, as it seldom is. While longer segments may be used when water-filled polyethylene pipe is used as a heat transfer agent, since plastic pipe is typically more flexible than copper tubing, in a DX system application, segments should preferably be limited to a maximum of 5 foot lengths, with a maximum of 4 foot lengths being preferable.  
         [0082]     For example, one will need to add 1.5 pounds of additional weight per foot of water-filled borehole to offset the buoyancy factor created by a ¾ inch wall closed cell insulation surrounding a ⅜ inch O.D. refrigerant transport liquid line. Thus, if 2 inch diameter steel tubing is used for a weight segment, one may need up to 8.5 segments that are 4 feet long each to offset the buoyancy in a 300 foot deep well. If 1.75 inch diameter steel tubing is used, one may need up to 11 segments that are 4 feet long each. If 1.5 inch diameter steel tubing is used, one may need up to 15 segments that are 4 feet long each. When water is encountered, one should drop the copper tubing as far as possible via its own weight, and then securely tape or shrink wrap on segments of steel tubing only as periodically necessary to continue the installation to its full well/borehole design depth, which depth is typically at least one hundred feet per ton of system design capacity.  
         [0083]     An alternative method of offsetting buoyancy would be to drop the copper tubing as far as possible via its own weight, using a 1.25 inch (not a 1 inch) trimme tube and then slowly fill the grout line with Grout 111. As the Grout 111 fills the trimme tube, the weight of the grout in a 1.25 inch diameter trimme tube will push the copper tubing down, displacing the water as it goes. However, a plug must be placed in the bottom of the trimme tube that will be pulled out as the trimme tube is pulled up off the liquid and vapor refrigerant transport lines coupled together within the Torpedo at the lower distal end. The plug would be tied to the eyebolt extended from the cementitious grout filling the Torpedo unit, so that the plug secured to the eyebolt, which eyebolt is secured to the Torpedo, prevents the plug from traveling up as the trimme tube is pulled up and away from the bottom of the well during actual grouting. However, as filling a trimme tube with Grout 111 is very cumbersome, the typically preferred method of off-setting buoyancy would be to as previously described hereinabove. Consequently this described alternate method will not be shown herein in the drawings.  
         [0084]     15. Plastic Coating for Copper Tubing.  
         [0085]     Apply a relatively thin plastic, or the like, coating to the exterior surface of sub-surface copper, or the like, tubing used for DX heating/cooling systems to assist in preventing damage from corrosive soils/water/materials. Conventional plastic coatings for underground/underwater copper tubing is comprised of a thick, strong, coating, typically comprised of a 0.70 mm, or greater, thick coating, which is also designed to be strong enough to optionally decrease the wall thickness of the copper so as to lower copper costs. However, such a thick plastic coating inhibits heat transfer in a DX system design. Consequently, a thinner walled plastic coating would be preferable for a DX system underground/underwater/within materials (such as concrete or the like) application, with the coating being only 0.60 mm thick, or less. The plastic coating could be comprised of at least one of polyethylene, teflon, or the like. A 0.60 mm thick, or less plastic coating of polyethylene, for example, will typically not inhibit heat transfer by any more than an approximate 2% degradation, which is acceptable in a typical DX system design, as safety margins in excess of 2% are typically always incorporated into sub-surface heat exchange line length exposure distances.  
         [0086]     For a more uniform heat absorption/rejection rate, along the entire length of a DX system sub-surface refrigerant transport heat exchange tube, with a plastic, or the like, coated exterior surface, it would be preferable to periodically decrease/increase the thickness of the coating. The thicker the coating, the slower the heat absorption/rejection rate, and the thinner the coating, the faster the heat absorption/rejection rate.  
         [0087]     16. Double Direct Exchange System.  
         [0088]     In the heating mode, any direct exchange geothermal heat acquisition tubing array may be used, preferably those taught by Wiggs. However, instead of transferring the heat acquired from the geothermal source to an air handler with an electric fan, or to a hydronic system with a water circulating pump, the heat would preferably be transferred directly to the air or water desired to be heated via convective heat transfer through a secondary heat exchange loop without the necessity of a secondary power draw, such as that occasioned by an electric fan or a water pump. The use of a sub-surface DX geothermal convective heat exchange system in conjunction with a secondary DX convective heat exchange system is hereby terms a “double direct exchange system”.  
         [0089]     For a double direct exchange system used to heat concrete swimming pools, or the like, insulation should preferably be placed around the base and sides of the pool, and the secondary heat exchange loop should preferably be placed between the insulation and the water containment means, such as within the pool&#39;s concrete shell for example.  
         [0090]     Preferably, so as to avoid any undue wear on the heat exchange tubing within the concrete shell of the pool, the heat exchange tubing would be coated with a plastic coating, thick enough to protect the tubing, but thin enough so as not to unduly inhibit heat transfer. In this regard, in order to enhance even heat exchange, decreasing thicknesses of the plastic coating would be utilized.  
         [0091]     Preferably, whether coated with plastic or not, all U bends in the heat exchange tubing within the concrete would be insulated with a closed cell foam insulation, so as to provide room for expansion/contraction at the ends of the tubing where the tubing was not confined by concrete.  
         [0092]     Alternatively, the heat exchange tubing would be placed on top of the insulation around the base and sides of the pool, and then covered with a thin plastic sheet. The concrete would then be poured on top of the plastic sheet, with the heat exchange tubing below, and with the insulation between the tubing and the ground. This would enable the  
         [0093]     In such a secondary heat exchange loop, the heat exchange tubing (typically copper, or the like) may be comprised, for example, of an array of ¼ inch 100 foot long tubes that are one of horizontally inclined or sloped, with the slope extending in the direction of the refrigerant flow in the heating mode, so that the condensing refrigerant vapor, as it rejects its heat into the concrete/pool water, will drain to a lower elevation via gravity flow.  
         [0094]     Such a system may be operated in a reverse cycle to chill, or cool, the water in a swimming pool. However, a reverse cycle operation of a double direct exchange system operating within the atmosphere of a structure would require a condensate drainage system to collect and remove the interior moisture condensing any exposed interior air heat exchange tubing.  
         [0095]     In any double direct exchange system, if an array of ¼ inch O.D. refrigerant grade refrigerant transport tubing is utilized as the secondary heat exchange loop, one should preferably utilize an array of 6 such ¼ inch O.D. tubes per ton of maximum heating/cooling system design capacity, where 1 ton equals 12,000 BTUs.  
         [0096]     Additionally, in a double direct exchange system, the secondary heat exchange loop could optionally be comprised of at least one, optionally finned, vapor refrigerant transport tube/line. The at least one, optionally finned, vapor refrigerant transport tube/line would be coupled to at least one liquid refrigerant transport line at the distal end of the secondary heat exchange loop, with the liquid line making at least a 1 inch, and preferably at least a 6 inch, vertically and downwardly oriented U bend prior to coupling to the vapor line at the higher elevation. The U bend should preferably be at the lowest point of the entire secondary heat exchange loop, and the vapor line must be one of at least horizontally oriented and downwardly sloped to the U bend.  
         [0097]     Preferably, such heat exchange loops would be comprised of a ¾ inch O.D. copper refrigerant grade vapor refrigerant transport line, or the like, that is at least 100 feet long per ton of system design capacity, with at least 120 feet long per ton being preferred, when the vapor line is embedded in a heat conductive material such as cement, concrete, or the like.  
         [0098]     Preferably, such heat exchange loops would be comprised of at least 5⅜ inch O.D. copper refrigerant grade vapor refrigerant transport lines, or the like, that are at least 100 feet long per ton of system design capacity, with at least 120 feet long per ton being preferred, when the vapor line consists of finned tubing solely exposed to the interior air. The vapor refrigerant transport line may optionally be distributed into multiple smaller lines that have a total of the same equivalent interior volume of refrigerant.  
         [0099]     In a double direct exchange system, the secondary heat exchange loop tubing should be comprised of one ¾ inch O.D. refrigerant grade copper tubing, or the like, or of multiple smaller tubes with a total equivalent interior diameter, for use in conjunction with up to a 30,000 BTU compressor. The heat exchange tubing should be comprised of one ⅞ inch O.D. refrigerant grade copper tubing, or the like, or of multiple smaller tubes with a total equivalent interior diameter, for use in conjunction with a 31,000 BTU compressor up to an 83,000 BTU compressor.  
         [0100]     In a double direct exchange system secondary heat exchange loop, the connecting liquid line portion of the secondary loop, which will travel from the distal end of the larger heat exchange tubing back through the system&#39;s compressor unit to the sub-surface geothermal evaporator, should be comprised of ⅜ inch O.D. refrigerant grade copper tubing, or the equivalent, for use in conjunction with up to a 30,000 BTU compressor. In a double direct exchange system secondary heat exchange loop, the connecting liquid line portion of the secondary loop, which will travel from the distal end of the larger heat exchange tubing back through the system&#39;s compressor unit to the sub-surface geothermal evaporator, should be comprised of ½ inch O.D. refrigerant grade copper tubing, or the equivalent, for use in conjunction with a 31,000 BTU compressor up to an 83,000 BTU compressor.  
         [0101]     Lastly, in a double direct exchange system, in various applications, it would be preferable to at least one of distribute the heat in the heating mode and absorb/remove the heat in the cooling mode in a relatively uniform manner throughout the secondary portion of the double direct exchange system. This is accomplished by insulating the secondary portion of the heat transfer tubing with insulation of a decreasing insulation value. Thus, the first portion of the secondary heat exchange tubing would be insulated the heaviest, with the insulation thickness decreasing until the last portion of the tubing is reached, which would be un-insulated. For example, one may coat the first portion of the secondary heat exchange tubing with a 1.5 mm thick plastic polyethylene coating, with the thickness of the coating at least one of uniformly decreasing and periodically decreasing throughout the length of the secondary heat exchange tubing, with the final portion of the secondary tubing having no coating at all. Otherwise, a significant majority of the heat, via such secondary heat exchange tubing, will be transferred through the first portion of the secondary tubing, potentially overheating the first portion of the area to be heated and leaving the final portion of the area to be heated without adequate heat.  
         [0102]     16. Swimming Pool Application  
         [0103]     A double direct exchange system, as described above, would be an ideal application for heating a swimming pool, or the like.  
         [0104]     In such an application, so as to avoid any undue wear on the heat exchange tubing within the concrete shell of the pool, the heat exchange tubing would be coated with a plastic coating, thick enough to protect the tubing, but thin enough so as not to unduly inhibit heat transfer. In this regard, in order to enhance even heat exchange, decreasing thicknesses of the plastic coating would be utilized.  
         [0105]     Additionally, and/or alternately, in such an application, the sub-surface heat exchange tubing within the concrete shell of the pool would typically have U bends, which U bends should preferably be surrounded with a closed cell insulation. The insulation would prevent the concrete from restricting the copper tubing from expanding/contracting at the U bends, where the most stress would typically occur, as the tubing within the insulation would be free to expand/contract as necessary due to fluctuating temperatures, thereby preventing undue wear and tear on the tubing.  
         [0106]     Alternately and/or additionally, in such an application, a thin plastic sheet may be placed under the floor and behind the concrete, or the like, walls of the pool. At least one of under and behind the thin plastic sheet would be the sub-surface heat exchange tubing, such as used in a DX heating/cooling system. At least one of under and behind the tubing would be a layer of insulation. The insulation helps insure the bulk of the heating/cooling effect of the DX system is transmitted to the water in the pool through the tubing, and is not lost into the surrounding ground. The plastic sheet, between the tubing and the concrete, prevents any restriction imposed upon the potential expansion/contraction of the tubing under varying temperature conditions, as well as prevents any exposure of the tubing to any potentially corrosive elements by means of the concrete, or the like, shell of the pool.  
         [0107]     17. Ground Loop Test Procedures.  
         [0108]     Once installed, a sub-surface ground loop in a DX system is typically good. However, if an unknown kink in a line has occurred during system, or if a pebble or some other debris has accidentally fallen into the line set during installation, such restriction could impair system operation. The only solution would be to replace the well once the system had been fully installed and operation had been found to be improper. In order to avoid such an expense in ascertaining a blocked line in a sub-surface line set, at least one of two tests may be conducted prior to grouting/covering the sub-surface line, so that if a restriction is found, the sub-surface line set may be easily removed and repaired prior to grouting and/or backfilling.  
         [0109]     One test would be to charge the line with dry nitrogen and to time the release. For example, a restricted 300 foot deep well, with a ⅜ inch O.D. liquid line and a ¾ inch O.D. vapor line, with a 160 dry nitrogen charge, would experience an approximate 4 psi higher charge level at the end of a 30 second pressure release than would a clear and unrestricted line set in the same well.  
         [0110]     Another similar pressure release test would be to charge the sub-surface line set with 50 pounds, for example, of dry nitrogen and then release the charge through the liquid line for one minute only. If the lines are not restricted, in a one minute pressure release period, there will typically be: a 30 psi to 35 psi pressure drop in an approximate 195 foot long line set; an approximate 20 psi to 32 psi pressure drop in an approximate 255 foot long line set; and an approximate 18 psi to 25 psi pressure drop in an approximate 255 foot long line set.  
         [0111]     A second test option would be to drop a small lightweight plastic ball, or the like, into one of the lines at the above-surface end of the line set. Such a ball would preferably be small enough to roll through the U bend at the bottom and/or distal end of the sub-surface refrigerant loop, but would be large enough to be blocked by any significant restriction and/or kink in the line set. The ball would be blown out of the line set by means of a relatively small amount of dry nitrogen, or the like, such as only 50 psi. If the ball could not be blown out, a restriction would be evidenced. In such event, the dry nitrogen pressure would be blown into the opposite line to retrieve the ball and the test could be repeated. If the results were the same via two tests, the line set should be retrieved, repaired, and re-inserted prior to grouting and/or backfilling. A preferable plastic ball for testing in a ⅜ inch O.D. liquid refrigerant transport line would be a 6 millimeter, 0.24 caliber, plastic ball, such as that used in pellet guns, distributed by AirStrike, of P.O. Box 220, Rogers, Ariz., USA, 72757. such a plastic ball is lightweight enough to be easily blown out of a good and unrestricted line set, is tough enough not to crumble or break into pieces during testing, is large enough to become stopped by a significant restriction, and is small enough to pass through ⅜ inch O.D. tubing that has been cut with tubing cutters, but not reamed out.  
         [0112]     A preferable testing procedure would consist of dropping such a 6 mm plastic ball, into the top open end of the vapor refrigerant transport line extending from the top of the well, and waiting for about one full minute per 300 feet of depth, so as to insure the ball falls to the bottom. Next, a pressure hose would be attached and taped/sealed to the top end of the vapor refrigerant transport line, and a net, a sock, or the like, would be secured to the top open end of the smaller diameter liquid refrigerant transport line exiting the top of the well/borehole. 50 psi of pressure, preferably consisting of dry nitrogen, would then be sent into the vapor refrigerant transport line via the pressure hose. The other end of the pressure hose would be attached to a refrigerant gauge set also attached to a pressurized container of dry nitrogen, which container supplies the pressurized nitrogen for the test. If the sub-surface refrigerant transport tubing is not restricted, the plastic ball will be pushed up and out of the liquid refrigerant transport line, into the net or sock, at a rate of about 25 feet per second, plus or minus 4 feet per second.  
         [0113]     A 6 mm plastic ball would be preferable for use with a ⅜ inch O.D. liquid refrigerant transport line, which is coupled to a larger O.D. vapor refrigerant transport line, such as a ¾ inch O.D. vapor transport line, at the lower distal end of the sub-surface refrigerant transport loop. Such a 6 mm sized plastic ball is large enough to be stopped by any significant restriction, but is small enough to pass through any minor kink in the refrigerant lines, and is small enough to pass through any refrigerant segment that has been cut with refrigerant tubing cutters and accidentally not reamed out.  
         [0114]     If the liquid refrigerant transport line is larger than a refrigeration grade ⅜ inch O.D. line, with a 0.032 inch wall thickness, then a proportionately larger sized plastic ball needs to be used. If the liquid refrigerant transport line is smaller than a refrigeration grade ⅜ inch O.D. line, with a 0.032 inch wall thickness, then a proportionately smaller sized plastic ball needs to be used.  
         [0115]     Preferably, the test will be conducted before the well is grouted, so that if there is a problem, the tubing can be withdrawn from the well and repaired prior to grouting. This simple test can save thousands of dollars and time, otherwise lost if a refrigerant transport line is only found to be restricted by means of the traditional DX system operational test, after full job completion. A defective/restricted line set, after full job completion, can only be corrected by means of installing a complete new replacement line set, within a newly drilled and grouted well. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0116]      FIG. 1 a  side view of a simple and basic version of a deep well direct exchange/expansion geothermal heat pump system operating in a cooling mode.  
         [0117]      FIG. 2  is a side view of an example of a liquid line segment.  
         [0118]      FIG. 3  is a side view of an example of an air handler.  
         [0119]      FIG. 4  is a side view of an example of a DWDX system.  
         [0120]      FIG. 5  is a side view of an example of a copper tubing DWDX system installation spool.  
         [0121]      FIG. 6  is a side view of an example of a segment of the pre-assembled line set.  
         [0122]      FIG. 7  is a side view of an example of a segment of a Torpedo unit.  
         [0123]      FIG. 8  is a top view of an example of a near-surface, but sub-surface, DX trench geothermal heat exchange system.  
         [0124]      FIG. 9  is a side view of an example of a larger diameter vapor refrigerant transport line.  
         [0125]      FIG. 10  is a side view of an example of the distal end of a near surface DX trench system.  
         [0126]      FIG. 11  is a top view of an example of a multiple sub-surface geothermal heat exchange loops.  
         [0127]      FIG. 12  is a side view of an example of sub-surface heat exchange tubing installed under water.  
         [0128]      FIG. 13  is a top view of an example of sub-surface heat exchange tubing.  
         [0129]      FIG. 14  is a top view of an example of sub-surface heat exchange tubing.  
         [0130]      FIG. 15  is a top view of an example of sub-surface heat exchange tubing.  
         [0131]      FIG. 16  is a side view of an example of a larger diameter refrigerant transport heat exchange tubing with attached fins installed within a containment box.  
         [0132]      FIG. 17  is a side view of an example of refrigerant transport tubing within a protective encasement.  
         [0133]      FIG. 18  is a side view of an example of a closed cell type insulated liquid refrigerant transport line and larger diameter, un-insulated, vapor refrigerant transport line entering a well/borehole.  
         [0134]      FIG. 19  is a side view of an example of a coating applied to the exterior surface of sub-surface heat exchange tubing.  
         [0135]      FIG. 20  is a side view of an example of a sub-surface refrigerant transport heat exchange tube with varying thicknesses of a coating.  
         [0136]      FIG. 21 a  side view of an example of a double direct exchange heating/cooling geothermal heat pump system operating in a cooling mode.  
         [0137]      FIG. 22  is a side view of an example of sub-surface heat exchange tubing within concrete.  
         [0138]      FIG. 23  is a side view of an example of a floor/wall structure.  
         [0139]      FIG. 24  is a side view of an example of an apparatus for an integrity testing method. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0140]     The following detailed description is of the best presently contemplated mode of carrying out the invention. The description is not intended in a limiting sense, and is made solely for the purpose of illustrating the general principles of the invention. The various features and advantages of the present invention may be more readily understood with reference to the following detailed description taken in conjunction with the accompanying drawings.  
         [0141]     Referring now to the drawings in detail, where like numerals refer to like parts or elements, there is shown in  FIG. 1 a  side view of a simple and basic version of a deep well direct exchange/expansion geothermal heat pump system operating in a cooling mode.  
         [0142]     A refrigerant fluid (not shown) is transported, by means of a compressor&#39;s  1  force and suction, inside a larger diameter un-insulated sub-surface refrigerant vapor transport/heat exchange line tube  11 , which is located below the ground surface  4  within a heat conductive, watertight pipe  5 . A smaller diameter sub-surface liquid refrigerant transport line tube  2 , which is surrounded by insulation  3 , also extends within the heat conductive, watertight pipe  5  all the way to the pipe&#39;s sealed lower end/bottom  6 , which pipe  5  has been inserted into a deep well borehole  7  all the way to the bottom  8  of the deep well borehole  7 . As the sub-surface liquid refrigerant transport tube  2  reaches the sealed pipe bottom  6 , the sub-surface liquid tube  2  forms a U bend  9 , which constructively acts as a liquid refrigerant trap, and the sub-surface liquid tube  2  is thereafter coupled, with a refrigerant tube coupling  10 , to the larger diameter un-insulated sub-surface refrigerant vapor transport/heat exchange tube  11 . As the refrigerant fluid flows down within the larger diameter un-insulated sub-surface refrigerant transport/heat exchange line tube  11 , on its way to the smaller diameter sub-surface liquid refrigerant transport line tube  2 , the refrigerant transfers heat into the cooler natural earth  23  geothermal surroundings below the ground surface  4  and is condensed into a cool liquid refrigerant form, as heat always travels to cold.  
         [0143]     The cooled refrigerant fluid, which has rejected excessive heat into the earth  23  below the ground surface  4 , condenses into a mostly liquid refrigerant form and travels up from the U bend  9  near/at the sealed pipe&#39;s lower end/bottom  6  into an exterior refrigerant transport liquid line tube  25 , which is surrounded by insulation  3 , through an exterior structure wall  24 , and into interior liquid refrigerant transport line tubing  27 . The liquid refrigerant then travels around and through the first pin restrictor  29  (in the heating mode, which is not shown as the reverse cycle mode of operation is well understood by those skilled in the art, the refrigerant flows in a reverse direction only through the hole in the center of the pin restrictor, and not additionally around the pin, so that the flow of the refrigerant is restricted and metered, as is well understood by those skilled in the art) within the first single piston metering device  20 , through the receiver  18 , which automatically adjusts the optimum amount of refrigerant charge flowing through the system in each of a heating mode and a cooling mode. In the cooling mode, most all of the refrigerant flows out of the bottom  35  of the receiver  18 , while in the heating mode (not shown), when the refrigerant is flowing in the opposite direction through the receiver  18  (as is well understood by those skilled in the art), the receiver  18  fills with liquid to a predetermined containment point  36 , which point  36  is calculated for maximum capacity so as to contain one pound of refrigerant for every forty feet in depth of the liquid line  2  within the deep well/borehole  7 . However, for optimal efficiency, the receiver  18  fills with liquid to a predetermined containment point  36 , which point  36  is calculated for maximum capacity so as to contain one pound of refrigerant for every fifty feet in depth of the liquid line  2  within the deep well/borehole  7 . The said respective one pound per  40  feet, or per 50 feet, containment point  36  design within the receiver  18  is preferably calculated based upon the depth of a ⅜ inch O.D. liquid refrigerant grade transport line  2 , situated within a well/borehole  7 , within a DWDX system design, or the equivalent thereof when other line set sizes are utilized, exclusive of the trenched line(s) to/from the well(s) (not shown herein but well understood by those skilled in the art) and exclusive of any other DX system refrigerant containment components.  
         [0144]     In the heating mode, when the refrigerant flow travels through the first single piston metering device  20 , as is well understood by those skilled in the art even though not shown herein, the optimum sizing of the first pin restrictor  29  within the first single piston metering device  20 , is as explained and set forth under Summary Of Invention, Number 2, hereinabove, which is incorporated herein by reference. Although in a typically cooling to heating season period, the ground, which has been absorbing rejected heat all summer, will typically cool enough to permit instant DX system heating mode operation with only a properly sized heating mode first pin restrictor  29 , if the seasonal change is extremely abrupt and fast, a pressure regulated heating mode refrigerant by-pass vale  41  within a heating mode by-pass line  42  around the heating mode pin restrictor  29  may be necessary so as to permit instant system heating mode operation without the system tripping off via its safety high pressure cut off switch  43  (the operation of a pressure regulated valve and of a high pressure cut-off switch are well understood by those skilled in the art and are therefore not shown in detail herein). To accomplish this optional heating mode protective means, one should preferably add a heating mode by-pass pressure regulated valve  41 , also referred to as an automatic expansion valve (“AXV”), so as to assist transition from the cooling mode to the heating mode so that the valve opens to a specifically designed interior diameter, as is more fully set forth hereinabove under Summary Of Invention, Number 3, hereinabove, which is incorporated herein by reference.  
         [0145]     The refrigerant then flows through the self-adjusting thermal expansion valve  16 , as well as through a thermal expansion valve by-pass line  17 , which line  17  contains a second single piston metering device  37 , also known as a thermal expansion pin restrictor device. The thermal expansion valve by-pass line  17  and second pin restrictor  38  within the second single piston metering device  37  permits enough refrigerant flow to by-pass the self-adjusting thermal expansion valve  16  so as to enable system operation in the cooling mode at the beginning of the cooling season when the ground is very cold, but does not permit enough refrigerant to by-pass the self-adjusting thermal expansion valve  16  so as to materially impair system operation when the ground warms up by means of heat rejection during the warm summer months. The optimum sizing of the second pin restrictor  38  within the second single piston metering device  37 , all within the by-pass line  17 , is as explained and set forth under Summary Of Invention, Number 4, hereinabove, which is incorporated herein by reference.  
         [0146]     The refrigerant fluid next flows through interior located finned heat exchange tubing  14 , also commonly called an air handler, with an adjacent fan  15  designed to blow hot interior air over the cooler refrigerant fluid within the finned heat exchange tubing  14  so as enable the cooler refrigerant to absorb and remove excess heat from the interior air.  
         [0147]     The warmed refrigerant fluid, having absorbed excessive heat from the interior air, is transformed into a mostly vapor state, and then flows through an interior located reversing valve  12 , into an accumulator  13 , which catches and stores any liquid refrigerant which has not fully evaporated, and then travels into the compressor  1 . The compressor  1  compresses the cooler refrigerant vapor into a hot refrigerant gas/vapor. The hot refrigerant vapor then travels, by means of the force of the compressor  1 , through the oil separator  30 . The oil separator  30  has a small oil return line  31  that returns oil, which has escaped from the compressor  1 , to the suction line portion  32  of the interior vapor refrigerant transport line tubing  28 , which suction line portion  32  is located prior and proximate to the accumulator  13 , by means of oil return line alternate route A  33 . In an alternative, the oil could be returned, by means of the oil return line  31 , directly into the accumulator  13 , as is shown herein by means of oil return line alternate route B  34 . The refrigerant fluid then travels through the interior located reversing valve  12 , back through the exterior structure wall  24 , through the exterior refrigerant transport vapor line tube  26 , which is surrounded by insulation  3 , and back into the larger diameter un-insulated sub-surface refrigerant vapor transport/heat exchange line tube  11 , which is located below the ground surface  4 , where the geothermal heat exchange process is repeated.  
         [0148]     All above ground surface  4  interior liquid refrigerant transport line tubing  27 , and all above ground surface  4  interior vapor refrigerant transport line tubing  28 , are fully insulated with rubatex, or the like, as is common in the trade, which is well understood by those skilled in the art and, therefore, is not shown herein.  
         [0149]     So as to avoid non-heat conductive air gaps, the remaining interior portion of the heat conductive watertight pipe  5 , located below the ground surface  4 , is filled with a heat conductive fluid mixture of water and anti-freeze  21 . For a similar purpose, the space below the ground surface  4 , between the exterior wall of the pipe  5  and the interior wall of the deep well borehole  7 , is filled with a heat conductive grout  22 , which is in direct thermal contact with the adjacent and surrounding earth  23 .  
         [0150]     An optional low pressure cut-off switch  19  is also shown for a secondary means of compressor  1  shut-off in the event of a refrigerant leak or other low pressure operational event. If used, the low pressure cut-off switch  19  should be set/designed not to shut off the compressor  1  unless there has been a continuous minimum of  10  minutes of system operation under pressure conditions below the requisite minimum. However, even though shown herein, it is preferably unnecessary to employ the use of a secondary low pressure cut off switch  19 , since the compressor&#39;s own internal safety cut-off mechanism will shut the compressor off should it become overheated due to an inordinate period of operation under too low of a refrigerant pressure condition. Thus, in a preferable design, the low pressure cut of switch  19  shown here would simply be eliminated.  
         [0151]     In lightening prone areas, such as the State of Florida, a design improvement to help prevent attracting lightening to underground copper tubing would consist of placing a non-electrical conductive covering  39 , such as a rubber mat or the like, over the top of the well/borehole  
         [0152]     The operation of a low pressure cut-off switch  19 , a compressor  1 , an electric powered fan  15 , a self-adjusting thermal expansion valve  16 , and their requisite and appropriate electrical wiring, as well as the operation of all other system components, are well understood by those skilled in the art and are, therefore, neither shown nor described herein in detail.  
         [0153]      FIG. 2  is a side view of a liquid line segment  44 . The liquid line segment  44  is comprised of a first refrigerant flow cut-off valve  45  (which is well understood by those skilled in the art), a refrigerant filter/dryer  46  (which is well understood by those skilled in the art), an optional refrigerant transport liquid line distributor  47  (which is well understood by those skilled in the art), and two respective heating mode single piston metering devices  20  situated on each distributed respective liquid refrigerant transport line  2 , each of which respective liquid refrigerant transport lines  2  are coupled to secondary refrigerant flow cut-off valves  48 . Smaller DX systems with 30,000 BTU design capacities typically require no distributor  47  and only one heating mode single piston metering device  20 , with only one secondary refrigerant flow cut-off valve  48 , although systems with greater BTU design capacities typically require at least two respective heating mode single piston metering devices  20  situated on each distributed respective liquid refrigerant transport line  2 , with respective secondary cut-off valves  48 , as shown herein. A DX system compressor box  49 , containing DX system operational equipment, as more fully shown in  FIG. 1  hereinabove, is shown with the liquid line segment attached. Although not fully shown herein, as is well understood by those skilled in the art, in the heating mode, the refrigerant travels from the compressor box  49  through the liquid line assembly  44 , through the sub-surface heat exchanger (not shown herein), and back into the compressor box  49  by means of the vapor refrigerant transport lines/tubes  11 . Here, since the liquid refrigerant transport lines  2  are distributed, so are the vapor refrigerant transport lines  11  by means of a vapor line distributor  50 .  
         [0154]      FIG. 3  is a side view of an air handler  51  (which is well understood by those skilled in the art). Generally, an air handler  51  is comprised of a metal box containing finned heat exchange tubing  14  and an electric powered fan/blower  15 . Here, a cooling mode TXV by-pass pressure regulated valve  52 , also referred to as an automatic expansion valve (“AXV”  52 ), is shown to assist transition from the heating mode to the cooling mode in a DX system.  
         [0155]     Preferably, the valve  52  is designed to open to an interior diameter of at least the size of the actual BTU size, in thousandths, of the compressor (the system&#39;s compressor is not shown herein, but is number  1  in  FIG. 1  hereinabove) in the compressor unit/box (the compressor box is not shown herein, but is number  49  in  FIG. 2  hereinabove) multiplied by 0.00009, with no less than multiplied by 0.00009, and with preferably no more than multiplied by 0.00018, to be opened when the refrigerant suction pressure is 85 psi (plus or minus 5 psi) or less, and to be closed when the refrigerant suction pressure is above 85 psi (plus or minus 5 psi). Match the resulting number, which will be the area of the orifice, to the closest pin size diameter if to be measured in pin restrictor sizing (pin restrictor diameters and sizing are well known to those skilled in the art). The lower the refrigerant pressure, the greater the opening in the valve.  
         [0156]     Alternately, although not as precise as individually tailored by-pass valves for each respective compressor size, a one size fits all valve opening to the actual BTU size, in thousandths, should preferably be as explained and set forth under Summary Of Invention, Number 5, hereinabove, which is incorporated herein by reference.  
         [0157]     The AXV valve  52  should be an external equalized valve, with a capillary tube  53  extended from the AXV valve  52  to the low pressure vapor line exiting the air handler  51 . The AXV valve  52  should preferably be an adjustable type valve that can be set to shut off at any pressure between 40 psi and 100 psi., with an 85 psi shut off point being preferable for a DX system application. A standard automatic self-adjusting thermal expansion valve  16  is also shown herein, which standard valve  16  is well understood by those skilled in the art.  
         [0158]     Additionally, differing air handler  51  manufacturers utilize differing finned tubing  14  lengths per ton of size design capacity. However, most air handler  51  manufacturers utilize finned tubing  14  with twelve to fourteen fins per inch length. Since differing manufacturers utilize differing lengths of tubing per ton of design capacity, it is inefficient to prescribe a certain tonnage air handler  51  to be used with a particular DX system BTU compressor (compressor not shown herein, but is number  1  in  FIG. 1 ) size. Further, to optimize DX system efficiencies, testing has shown it is impractical to match a  3  ton compressor (compressor not shown herein, but is number  1  in  FIG. 1 ) with a  3  ton air handler  51 , as most all predecessor conventional system designs call for. Testing has shown that in order to optimize the efficiency of a DX system design, the air handler  51  must be sized to 120% of the maximum system design load (design loads are typically calculated as per ACCA Manuel J, or the like, as is well understood by those skilled in the art), and must have sixty feet per ton, plus or minus five feet, of finned ⅜ inch O.D. interior heat exchange refrigerant transport tubing  55 . Fifty-five to sixty feet of the ⅜ inch O.D. tubing  55  is preferable in the heating mode. Sixty to sixty-five feet of the ⅜ inch O.D. tubing is preferable in the cooling mode.  
         [0159]      FIG. 4  is a side view of a basic and very simple Deep Well DX (a “DWDX”) system. The charging formula is for a DWDX system, or the like, using R- 410 A refrigerant (the refrigerant is not shown, but circulates within the refrigerant transport tubing,  55  and  11 , and other components of the system, as is well understood by those skilled in the art), with a sub-surface ⅜ inch O.D. liquid refrigerant grade transport line  55  in the well/borehole  7 . The ⅜ inch line  55  is refrigerant grade copper with a 0.032 inch wall thickness. The system has a larger O.D. refrigerant grade vapor transport line  11  in the well  7 , with a sub-surface ¾ inch O.D., or larger, vapor refrigerant grade geothermal heat exchange transport line  57  in the well/borehole  7  being preferred. The correct system charge is calculated by adding the sum of the following:  
         [0160]     A. Total depth of the ⅜ inch O.D. liquid line  55  in the well  7  times 0.0375 pounds. The total depth is the distance between the top  56  of the well  7  and the liquid line U bend  9  near the bottom  8  of the well  7  in the earth  23 .  
         [0161]     B. 50% of total length of finned ⅜ inch O.D. tubing  14  in the in the air handler  51  multiplied by 0.0375 pounds.  
         [0162]     C. Compressor unit/box  49  content of liquid refrigerant.  
         [0163]     D. Add the amount of liquid refrigerant contained in the system&#39;s filter/dryer  46  (for example, a Parker Bi-Directional R-410A Heat Pump Filter/Dryer Model BF164-XF holds about 0.761875 pounds), exclusive of any filter/dryer in the compressor box  49 , which has already been taken into account in the compressor unit/box  49  content.  
         [0164]     E. Add the amount of liquid refrigerant in all liquid line ball cut-off valves,  45  and  48  (typically about 0.05 pounds each), exclusive of the ball cut-off valves, if any, in the compressor box  49 , which have already been taken into account in the compressor unit/box  49  content.  
         [0165]     F. Measure the total liquid transport line  55  length between the top  56  of the well/borehole  7 , shown here at the ground surface  4 , and the compressor unit/box  49  and multiply by the full liquid refrigerant weight content of the liquid refrigerant transport line  55  in pounds. For example, multiply by 0.0375 pounds if it is a preferred ⅜ inch O.D. refrigerant grade copper line  55 , but multiply by 0.06875 if it is a ½ inch O.D refrigerant grade copper line. Although the liquid transport line  55  is shown here as being located between the top  56  of the well/borehole  7  and the compressor unit/box  49  at an above ground surface  4  location, this segment of the liquid transport line  55  is typically buried below the ground surface  4  (not shown herein but well understood by those skilled in the art).  
         [0166]     G. Measure the total liquid transport line  55  length between the air handler  51  and the compressor unit/box  49  and multiply by the full liquid weight content of the line in pounds. For example, multiply by 0.0375 pounds if it is a ⅜ inch O.D. line  55 , but multiply by 0.06875 if it is a ½ inch O.D line.  
         [0167]     H. For a cooling mode charge, add an additional one pound of refrigerant for every forty feet of ⅜ inch O.D. refrigerant grade liquid line  55  in the well for maximum system operational capacity and humidity removal. If humidity removal is not a concern, add an additional one pound of refrigerant for every fifty feet of ⅜ inch O.D. refrigerant grade liquid line  55  in the well for maximum efficiency.  
         [0168]     I. If the system is designed to operate in a reverse-cycle mode (heating and cooling), the system must have a liquid line receiver  18  that holds the preferred charge differential between the heating mode and the cooling mode. Additionally, the receiver  18 , which should preferably have only one refrigerant entrance  58  and only one refrigerant exit  59 , will typically have some constant amount of liquid content in its bottom, regardless of the system operational mode, which constant amount of refrigerant, in pounds, must be added.  
         [0169]     J. If the system is designed to operate in the heating mode with a heating mode pin expansion device/single piston metering device  20 , shown here as installed between the filter/dryer  46  and the secondary cut-off valve  48 , the weight, in pounds, of the liquid refrigerant content of the single piston metering device  20  must be added to the total.  
         [0170]     The total of the appropriate above sums will equal the correct system charge.  
         [0171]     To determine the optimum charge in DX systems utilizing other than ⅜ inch O.D. liquid refrigerant transport lines  55  and ¾ inch O.D., or larger, vapor refrigerant transport lines  57 , the charge should preferably be determined by the above formula, except the equivalent refrigerant content of the actual interior volume of the liquid refrigerant transport line used must be matched to the interior volume of a ⅜ O.D. liquid refrigerant grade transport line/tube  55  as per the above formula. For example, if multiple liquid refrigerant transport lines of a smaller interior diameter were utilized than that of a ⅜ inch O.D. refrigerant grade copper tube  55 , then the content of all multiple smaller lines must match that of the content of a system designed with at least one of one and multiple ⅜ inch O.D. refrigerant grade copper tube(s)  55 . As another example, if a larger liquid refrigerant transport line was used than that of a ⅜ inch O.D. refrigerant grade copper tube, then the interior content of the larger tube must match that of the content of a system designed with at least one of one and multiple ⅜ inch O.D. refrigerant grade copper tube(s)  55 .  
         [0172]      FIG. 5  is a side view of a copper tubing DWDX system installation spool  60 , with pre-assembled line sets  61  for DX system field loop installations. The spool  60  should preferably have at least a twenty-four inch wide holding tube  62  diameter, with both a smaller diameter insulated  3  refrigerant transport line  2  and an un-insulated, larger diameter, refrigerant transport line  11  on the same holding spool.  
         [0173]     The holding spool should preferably have sides  65  extending past the outer layer  63  of the pre-assembled refrigerant transport line set  61 , but with a four foot, or less, total side diameter  64  so as to facilitate shipping on a standard four foot wide pallet.  
         [0174]     Prior to assembly, the pre-assembled line set  61 , with a cementitious grout-filled (preferably Grout  111 ) “Torpedo” unit  66  should be evacuated of air with a vacuum pump  67 . The vacuum pump  67  has an external electrical power supply line  68  (vacuum pumps are well understood by those skilled in the art), and should preferably be used to pull at least a 250 micron vacuum. The line set  61  and Torpedo unit  66  should then preferably be charged with a dry nitrogen holding charge of 50 pounds, or the like, for shipment and installation. Charging with a 50 pound holding charge of dry nitrogen is well understood by those skilled in the art and is therefore not shown herein.  
         [0175]     The 250 micron vacuum will insure there are no leaks, and the 50 pound holding charge will insure no leaks have occurred during either shipment or installation. Both pulling the vacuum and inserting the holding charge of dry nitrogen are effected by means of capping  68  one of the ends of at least one of the liquid refrigerant transport line  2  and the vapor refrigerant transport line  11 , and then placing a schraeder valve  69  (a schraeder valve is well understood by those skilled in the art) at the end of the other for refrigeration gauge set attachment (refrigeration gauges are well understood by those skilled in the art and are therefore not shown herein). This procedure comprises a significant time saving and efficiency improvement over the historical and traditional method of installing sub-surface heat exchange tubing in a DX system, where the tubing is installed, sealed, and pressure tested prior to pulling a vacuum and charging, which is more time consuming and is not as trustworthy as initially pulling a vacuum. Pulling a vacuum cannot be done to  250  microns in a DX system if there is a leak, whereas a pressure test could take hours or days to reveal a very slight leak.  
         [0176]      FIG. 6  is a side view of a segment of the pre-assembled line set  61 , comprised of an insulated  3  smaller diameter liquid refrigerant transport line  2  and an un-insulated larger diameter vapor refrigerant transport line  11  surrounded by a spiraled fiber tape  70 , or the like, so as to keep the lines,  2  and  11 , together as they are lowered into the well/borehole (not shown in this drawing, but shown as number  7  in  FIG. 1  hereinabove). The tape  70  must be spiraled at least once every eight to twelve inches to be effective.  
         [0177]      FIG. 7  is a side view of a segment of a Torpedo unit  66  is comprised of a containment tube with a rounded nose  71 , which tube  71  contains smaller diameter liquid transport refrigerant transport tubing  2  and larger diameter liquid transport refrigerant transport tubing  11 , with a lower liquid line  2  U bend  9 , and a cementitious heat conductive grout fill material  22 , preferably comprised of Grout  111 , which Grout  111  is shrink and crack resistant, with a very high 1.4 BTUs/Ft.Hr. Degrees F heat transfer rate.  
         [0178]      FIG. 8  is a top view of a near-surface, but sub-surface, DX trench geothermal heat exchange system. The geothermal sub-surface heat transfer tubing,  2  and  11 , is preferably comprised of equal lengths of a smaller diameter un-insulated refrigerant transport tubing  2  and of a larger diameter un-insulated refrigerant transport tubing  11 , and should preferably be installed with at least 100 feet of tubing per ton of the maximum heating/cooling BTU load design, as per ACCA Manuel J or the like, where 12,000 BTUs equal one ton of heating/cooling capacity. However, 120 feet per ton is a preferred length to assist in insuring optimum system operational efficiencies.  
         [0179]     In such a DX trench system, one smaller diameter liquid refrigerant transport line  2  would be coupled to one larger diameter vapor refrigerant transport line  11  at the distal end  72  of the sub-surface heat exchange loop.  
         [0180]     In such a DX trench system, the liquid refrigerant transport line  2  would preferably be comprised of one 120 foot long ⅜ inch O.D. refrigerant grade copper tube, or the like, per ton of system design capacity, with a maximum 360 foot distance per liquid line  2  segment in each respective loop.  
         [0181]     In such a DX trench system, the vapor refrigerant transport line  11  would preferably be comprised of one  120  foot long ¾ inch O.D. refrigerant grade copper tube, or the like, per ton of system design capacity, with a maximum 360 foot distance per vapor line segment in each respective loop. Further, the vapor line  11  must be at least one of horizontally and downwardly sloped  73  toward the distal end  72 , with a downward slope being preferred.  
         [0182]     In such a DX trench system, neither the vapor refrigerant transport line  11  used for subsurface heat exchange, nor the liquid refrigerant transport line  2  used for subsurface heat exchange, would be insulated, and the respective vapor line  11  and liquid line  2 , except for being coupled together at the distal end  72  of the loop, would be separated by at least twenty feet, with a thirty foot separation being preferable where land area permits. When the vapor line  11  and liquid line  2  near one another for connection to the DX system compressor unit, each line,  11  and  2 , should preferably be fully insulated  3 , with a closed cell insulation  3  (such as expanded polyethylene and/or neoprene, or the like) when they are at least within twenty feet of one another.  
         [0183]      FIG. 9  is a side view of a larger diameter vapor refrigerant transport line  11  in a near-surface DX trench system, where the vapor line  11  is preferably downwardly sloped.  
         [0184]      FIG. 10  is a side view of the distal end  72  of a near surface DX trench system, where the larger diameter vapor line  11  is coupled to the smaller diameter liquid line  2 . The liquid line  2  is comprised of at least a six inch vertically and downwardly oriented U bend  9  prior to coupling to the vapor line  11  at the at least six inch higher elevation. Both the vapor line  11  and the liquid line  2  are preferably buried within the earth  23  at least two feet below the frost line from the ground surface  4  in the area of system installation. The U bend  9  should preferably be at the lowest point of the entire heat exchange loop, and the vapor line  11  must be one of at least horizontally oriented and downwardly sloped to the U bend  9 . Preferably, such heat exchange loops, comprised of the joined and equal respective lengths of vapor line  11  and liquid line  2 , would not exceed 360 feet in length per loop.  
         [0185]      FIG. 11  is a top view of the multiple sub-surface geothermal heat exchange loops, comprised of larger diameter vapor lines  11  coupled at their respective distal ends  72  to respective smaller diameter liquid lines  2  in a near-surface trench system installation would preferably be joined together by means of a vapor line distributor  50  and a liquid line distributor  47  for refrigerant transportation to the compressor unit (not shown herein, but the same as number  1  in  FIG. 1 ) when design capacity called for more than one 320 foot loop of exposed sub-surface geothermal heat transfer tubing,  2  and  11 . Here, as in a single loop application, insulation  3  surrounds all sub-surface tubing within twenty feet of one another.  
         [0186]      FIG. 12  is a side view of sub-surface heat exchange tubing,  2  and  11 , installed under water  75 . When moving water  12  is available, such as at least one of a stream, a creek, a river, and a tidal area, and the like, a DX system with refrigerant transport heat exchange tubing,  2  and  11 , situated within the moving water  75  needs only forty feet per ton to operate at design system tonnage capacity (as per ACCA Manuel J or the like) with sixty feet per ton being preferred with a design safety margin. The heat exchange tubing,  2  and  11 , are shown as exposed to the water  75  via a downwardly sloped extended larger diameter sub-surface vapor refrigerant transport/heat exchange line/tube  11 , which is connected to a smaller diameter liquid refrigerant transport line  2 , by means of a coupling  74 , at the bottom/distal end  76  of the larger diameter sub-surface vapor refrigerant transport/heat exchange line/tube  11 . The refrigerant transport lines/tubing,  2  and  11 , would typically be insulated  3 , after exiting the water  75 , on the way to the compressor unit (the compressor is not shown herein, but is the same as number  1  in  FIG.1 ).  
         [0187]     The larger diameter, sub-surface, vapor refrigerant transport tubing  11  should preferably be comprised of ¾ inch O.D. refrigerant grade copper tubing, or the like, for use in conjunction with up to a 30,000 BTU compressor. The larger diameter vapor refrigerant transport tubing  11  should preferably be comprised of ⅞ inch O.D. refrigerant grade copper tubing, or the like, for use in conjunction with a 31,000 BTU compressor up to an 83,000 BTU compressor. When smaller vapor refrigerant transport tubing/lines is used (not shown herein), the interior diameter of the smaller tubing/lines should preferably approximately equal the interior diameter of the respective ¾ inch O.D. and ⅞ inch O.D. lines as described in this paragraph matching the varying respective compressor sizes.  
         [0188]     The connecting smaller diameter liquid refrigerant transport line  2 , which will travel from the distal and lowest end  76  of the larger vapor refrigerant transport tubing  11  back to the system&#39;s compressor unit, should preferably be comprised of ⅜ inch O.D. refrigerant grade copper tubing, or the like, for use in conjunction with up to a 30,000 BTU compressor. The connecting liquid refrigerant transport line  2 , which will travel from the distal and lowest end  76  of the larger vapor refrigerant transport tubing  11  back to the system&#39;s compressor unit, should be comprised of ½ inch O.D. refrigerant grade copper tubing, or the like, for use in conjunction with a 31,000 BTU compressor up to an 83,000 BTU compressor. When smaller liquid refrigerant transport tubing is used (not shown herein), the interior diameter of the smaller tubing/lines should preferably approximately equal the interior diameter of the respective ⅜ inch O.D. and ½ inch O.D. lines as described in this paragraph with the varying respective compressor sizes.  
         [0189]      FIG. 13  is a top view of sub-surface heat exchange tubing,  2  and  11 , with a larger diameter vapor refrigerant transport line  11 , coupled  74  at its lowest distal end  76  to a smaller diameter liquid refrigerant transport tube  2 , all installed under the surface of water (water is not shown herein since this is a top view). Here, the larger diameter vapor refrigerant transport line  11  is shown as being a looped, coiled, and largely spread apart line  11 . The design length and sizing of the refrigerant transport tubing,  2  and  11 , should preferably be the same as that described hereinabove in  FIG. 12 , which is incorporated herein by reference.  
         [0190]      FIG. 14  is a top view of sub-surface heat exchange tubing,  2  and  11 , with a larger diameter vapor refrigerant transport line  11 , coupled  74  at its lowest distal end  76  to a smaller diameter liquid refrigerant transport tube  2 , all installed under the surface of water (water is not shown herein since this is a top view). Here, the larger diameter vapor refrigerant transport line  11  is shown as being a looped, coiled, and modestly spread apart line  11 . The design length and sizing of the refrigerant transport tubing,  2  and  11 , should preferably be the same as that described hereinabove in  FIG. 12 , which is incorporated herein by reference.  
         [0191]      FIG. 15  is a top view of sub-surface heat exchange tubing,  2  and  11 , with a larger diameter vapor refrigerant transport line  11 , coupled  74  at its lowest distal end  76  to a smaller diameter liquid refrigerant transport tube  2 , all installed under the surface of water (water is not shown herein since this is a top view). Here, the larger diameter vapor refrigerant transport line  11  is shown as being comprised of a line  11  with multiple U bends  9 . The design length and sizing of the refrigerant transport tubing,  2  and  11 , should preferably be the same as that described hereinabove in  FIG. 12 , which is incorporated herein by reference.  
         [0192]      FIG. 16  is a side view of a larger diameter refrigerant transport heat exchange tubing  11 , with attached fins  77  so as to enhance heat transfer, installed within a containment box  78  made of a resistant material, such as at least one of titanium, Grout  111 , polyethylene, and the like, to prevent micro-organism damage. Micro-organisms in seawater eat stainless steel. Preferably, such a containment box  77  would be filled with a non-corrosive fluid (not shown herein), such as pure water or the like, and would have an expanded top portion  79  and an expanded bottom portion  80  to facilitate the collection and transfer of heat to the surrounding water  75  (the warmest water would naturally rise to the expanded top portion  79  of the containment box  77 , and the coolest water would naturally fall to the expanded bottom portion  80  of the containment box  77  in both the cooling mode and in the heating mode), all while the heat transporting refrigerant (refrigerant is not shown herein, as refrigerant is well understood by those skilled in the art) would be traveling from the top portion  81  of the downwardly sloped refrigerant transport heat transfer tubing  11 , with fins  77  to the bottom portion  82  in the cooling mode, and from the bottom portion  82  to the top portion  81  in the heating mode, thereby providing maximum heat transfer ability and efficiency.  
         [0193]     While submerged heat exchange tubing may be placed within a protective polyethylene containment box  78  covering, preferably a containment box  78  comprised of at least one of titanium and Grout  111  would be utilized, as polyethylene has a relatively poor heat transfer rate of only 0.225 BTUs/Ft. Hr. degrees F. However, protective piping  83 , within which both the un-fined vapor refrigerant transport line  11  and the liquid refrigerant transport line  2  (traveling to and from the heat exchange tubing  11 , with fins  77 , within the containment box  78 ) may be placed, may be comprised of a polyethylene pipe  84 , or the like. Insulation  3  would preferably be placed around all refrigerant transport tubing,  2  and  11 , situated above the water  75 .  
         [0194]      FIG. 17  is a side view of refrigerant transport tubing,  2  and  11 , within a protective encasement  85  of Grout  111 . When in salt water  75  and/or in water  75  that is at least one of corrosive and abrasive to copper or other refrigerant transport tubing, the refrigerant transport tubing,  2  and  11 , must be situated within a protective encasement  85 , such as at least one of Grout  111 , titanium, polyethylene, and a non-corrosive fluid filled pipe, and the like. The protective encasement  85  may be comprised of a shell (a shell is not shown here, but is the same as the shell type containment box shown as number  78  in  FIG. 16 ). In the alternative, the protective encasement  85  may be comprised of a solid material, such as Grout  111 , or the like. Grout  111  is highly heat conductive (1.4 BTUs/Ft.Hr. Degree F.), weighs about 18.5 pounds per gallon, is virtually water  75  impervious, and cures as a solid cementitious grout. A Grout  111  protective encasement  85  will, therefore, act as both a good heat transfer agent and as an anchor for the larger diameter, downwardly sloping, heat exchange refrigerant vapor transport tubing  11 , coupled  4  at the lower distal end  76  to the smaller diameter liquid refrigerant transport tubing  2 . The portions of the refrigerant transport tubing,  2  and  11 , above the water  75  would be insulated  3 .  
         [0195]      FIG. 18  is a side view of a closed cell type insulated  3  smaller diameter liquid refrigerant transport line  2  and a larger diameter, un-insulated, vapor refrigerant transport line  11  entering a well/borehole  7 , which well  7  extends beneath the ground surface  4  into the earth  23 . Here, water  75  is shown as filling the well  7  to a point near the ground surface  4 . Therefore, additional weight needs to be added to offset the buoyancy created by the closed cell insulation  3 . DX systems utilizing a ⅜ inch O.D., or less, liquid refrigerant line  2 , and utilizing a ¾ inch O.D., or less vapor refrigerant line  11 , typically require 4.5 inch to six inch diameter wells/boreholes, so as to provide enough room to easily insert the refrigerant transport lines,  2  and  11 , as well as the insulation  3  surrounding the liquid line  2 . Additionally, although not shown herein, a trimme tube is typically used to fill the annular space remaining within the well  7  with a grout. The trimme tube is typically close to the same weight as water  75  and has an open lower distal end. Thus, the trimme tube fills with water  75  as the rest of the closed-loop refrigerant tubing,  2  and  11 , and insulation  3  are all inserted into the water  75  filled well  7 . A trimme tube utilized for grout installation is well understood by those skilled in the art.  
         [0196]     Weight to offset the buoyancy created by the insulation  3  may preferably be added to a DX system by means of taping/tying 90 maximum five foot segments  86  of maximum two inch diameter steel, or the like, tubing/bars (two inch diameter weighs 10.68 pounds per foot . . . 1.75 inch diameter weighs 8.18 pounds per foot . . . 1.5 inch diameter weighs 6.01 pounds per foot) or smaller re-bar, or the like, to the refrigerant transport line set, comprised of the liquid refrigerant line  2 , the vapor refrigerant line  11 , and insulation  3  around the liquid line  2 , as needed. Prior to attachment by means of taping/tying  90 , the steel, or the like, tubing/bar maximum five foot long segment  86  to the copper tubing,  2  and  11 , the segment  86  should preferably be wrapped in a protective wrapping  87 , such as shrink wrap, tape, or the like, so as to protect the copper refrigerant transport tubing,  2  and  11 . Add as many segments  86  of maximum five foot long steel tubing segments  86  as necessary to offset the buoyancy, which is dependent upon the depth of the water  75  within the well/borehole  7 .  
         [0197]     However, there must not be a vertical gap (not shown) between the segments  86  being added. If a vertical gap exists, which is historically permissible when plastic polyethylene pipe (not shown) is used to transport water  75  as a geothermal heat exchange fluid, the soft copper refrigerant transport tubing,  2  and  11 , in a DX system application could be crimped/damaged during installation. Thus, in a DX system application, it is critical that the segments  86  must be placed directly above one another  88  or slightly overlapped  89 . A maximum of five foot long segments  86  should be used in a DX system application so as to avoid damaging the copper refrigerant transport tubing,  2  and  11 , and so as to avoid jamming the insertion, when the well/borehole  7  is not perfectly straight, as it seldom is. While longer than five foot segments  86  may be used when water-filled polyethylene pipe (not shown herein) is used as a heat transfer agent in a water-source heat pump system application (a water-source heat pump system is well understood by those skilled in the art and is not shown herein), since plastic pipe is typically more flexible than copper tubing,  2  and  11 , in a DX system application, segments  86  should preferably be limited to a maximum of five foot lengths, with a maximum of four foot lengths being preferable.  
         [0198]     The taping/tying  90  of the maximum five foot long segments  86  to the copper refrigerant transport tubing,  2  and  11 , should be done at the top  91  and at the bottom  92  of the segments  86  only, so as to only place a minimum of heat transfer inhibiting tape  90 , or the like, around the vapor refrigerant transport line  11  used for geothermal heat transfer, and so as to permit some flexibility between the segments  86  during installation into a well/borehole  7  that may not be perfectly straight, so as to avoid jamming.  
         [0199]     When water  75  is encountered in a well  7  during a DX system copper tubing,  2  and  11 , installation, where the liquid refrigerant transport line  2  is insulated  3 , one should drop the copper tubing,  2  and  11 , as far as possible via its own weight, and then securely apply a protective wrapping  87  of tape, shrink wrap, or the like, on maximum five foot long segments  86  of steel tubing, or the like, only as periodically necessary to continue the installation to its full well/borehole  7  design depth, which design depth is typically at least one hundred feet per ton of system design capacity.  
         [0200]      FIG. 19  is a side view of a relatively thin plastic, or the like, coating  93  applied to the exterior surface  94  of sub-surface copper, or the like, heat exchange tubing  95  used for DX heating/cooling systems to assist in preventing damage from corrosive soils/water/materials. Conventional plastic coatings  93  for underground/underwater copper heat exchange tubing  95  is comprised of a thick, strong, coating  93 , typically comprised of a 0.70 mm, or greater, thick coating  93 , which is also designed to be strong enough to optionally decrease the wall thickness of the copper tubing  95  so as to lower copper costs. However, such a thick plastic coating  93  inhibits heat transfer in a DX system design. Consequently, a thinner walled plastic coating  93  would be preferable for a DX system where the sub-surface heat exchange tubing  95  was installed in an underground/underwater/within materials (such as concrete or the like) application, with the coating  93  being only 0.60 mm thick, or less. The plastic coating  93  could be comprised of at least one of polyethylene, tefflon, or the like. A 0.60 mm thick, or less plastic coating  93  of polyethylene, for example, will typically not inhibit heat transfer by any more than an approximate 2% degradation, which is acceptable in a typical DX system design, as safety margins in excess of 2% are typically always incorporated into sub-surface heat exchange line length exposure distances.  
         [0201]     Preferably, so as to avoid any undue wear on the heat exchange tubing within the concrete shell of a swimming pool, or the like, the heat exchange tubing  95  would be coated with a plastic coating  93 , thick enough to protect the tubing, but thin enough so as not to unduly inhibit heat transfer.  
         [0202]      FIG. 20  is a side view of a sub-surface refrigerant transport heat exchange tube  95  with varying thicknesses of a plastic coating  93 . For a more uniform heat absorption/rejection rate, along the entire length of a DX system sub-surface refrigerant transport heat exchange tube  95 , with a plastic, or the like, coated  93  exterior surface  94 , it would be preferable to periodically decrease/increase the thickness of the coating  93 . The thicker the coating  93 , the slower the heat absorption/rejection rate, and the thinner the coating  93 , the faster the heat absorption/rejection rate. Here a refrigerant transport heat exchange tube  95  is shown as being coated with a heavy coating of plastic  96 , with a medium coating of plastic  97 , and with a thin coating of plastic  98 .  
         [0203]     In a swimming pool (not shown) heating application, for example, in order to enhance even heat exchange throughout the pool, decreasing thicknesses of the plastic coating  93  would be utilized.  
         [0204]      FIG. 21 a  side view of a simple and basic version of a double direct exchange heating/cooling geothermal heat pump system operating in a cooling mode.  
         [0205]     A refrigerant fluid (not shown) is transported, by means of a compressor&#39;s  1  force and suction, inside a larger diameter un-insulated sub-surface refrigerant vapor transport/heat exchange line tube  11 , which is located below the ground surface  4  within a heat conductive, watertight pipe  5 . A smaller diameter sub-surface liquid refrigerant transport line tube  2 , which is surrounded by insulation  3 , also extends within the heat conductive, watertight pipe  5  all the way to the pipe&#39;s sealed lower end/bottom  6 , which pipe  5  has been inserted into a deep well borehole  7  all the way to the bottom  8  of the deep well borehole  7 . As the sub-surface liquid refrigerant transport tube  2  reaches the sealed pipe bottom  6 , the sub-surface liquid tube  2  forms a U bend  9 , which constructively acts as a liquid refrigerant trap, and the sub-surface liquid tube  2  is thereafter coupled, with a refrigerant tube coupling  10 , to the larger diameter un-insulated sub-surface refrigerant vapor transport/heat exchange tube  11 . As the refrigerant fluid flows down within the larger diameter un-insulated sub-surface refrigerant transport/heat exchange line tube  11 , on its way to the smaller diameter sub-surface liquid refrigerant transport line tube  2 , the refrigerant transfers heat into the cooler natural earth  23  geothermal surroundings below the ground surface  4  and is condensed into a cool liquid refrigerant form, as heat always travels to cold.  
         [0206]     The cooled refrigerant fluid, which has rejected excessive heat into the earth  23  below the ground surface  4 , condenses into a mostly liquid refrigerant form and travels up from the U bend  9  near/at the sealed pipe&#39;s lower end/bottom  6  into an exterior refrigerant transport liquid line tube  25 , which is surrounded by insulation  3 , through an exterior structure wall  24 , and into interior liquid refrigerant transport line tubing  27 . The liquid refrigerant then travels around and through the first pin restrictor  29  (in the heating mode, which is not shown as the reverse cycle mode of operation is well understood by those skilled in the art, the refrigerant flows in a reverse direction only through the hole in the center of the pin restrictor, and not additionally around the pin, so that the flow of the refrigerant is restricted and metered, as is well understood by those skilled in the art) within the first single piston metering device  20 , through the receiver  18 , which automatically adjusts the optimum amount of refrigerant charge flowing through the system in each of a heating mode and a cooling mode. In the cooling mode, most all of the refrigerant flows out of the bottom  35  of the receiver  18 , while in the heating mode (not shown), when the refrigerant is flowing in the opposite direction through the receiver  18  (as is well understood by those skilled in the art), the receiver  18  fills with liquid to a predetermined containment point  36 , which point  36  is calculated for maximum capacity so as to contain one pound of refrigerant for every forty feet in depth of the liquid line  2  within the deep well/borehole  7 . However, for optimal efficiency, the receiver  18  fills with liquid to a predetermined containment point  36 , which point  36  is calculated for maximum capacity so as to contain one pound of refrigerant for every fifty feet in depth of the liquid line  2  within the deep well/borehole  7 . The said respective one pound per 40 feet, or per 50 feet, containment point  36  design within the receiver  18  is preferably calculated based upon the depth of a ⅜ inch O.D. liquid refrigerant grade transport line  2 , situated within a well/borehole  7 , within a double direct exchange heating/cooling system using a DWDX system design, or the equivalent thereof when other line set sizes are utilized, as one of its primary heat sources/heat sinks, exclusive of the trenched line(s) to/from the well(s) (not shown herein but well understood by those skilled in the art) and exclusive of any other DX system refrigerant containment components.  
         [0207]     In the heating mode, when the refrigerant flow travels through the first single piston metering device  20 , as is well understood by those skilled in the art even though not shown herein, the optimum sizing of the first pin restrictor  29  within the first single piston metering device  20 , is as explained and set forth under Summary Of Invention, Number 2, hereinabove, which is incorporated herein by reference. Although in a typically cooling to heating season period, the ground, which has been absorbing rejected heat all summer, will typically cool enough to permit instant DX system heating mode operation with only a properly sized heating mode first pin restrictor  29 , if the seasonal change is extremely abrupt and fast, a pressure regulated heating mode refrigerant by-pass vale  41  within a heating mode by-pass line  42  around the heating mode pin restrictor  29  may be necessary so as to permit instant system heating mode operation without the system tripping off via its safety high pressure cut off switch  43  (the operation of a pressure regulated valve and of a high pressure cut-off switch are well understood by those skilled in the art and are therefore not shown in detail herein). To accomplish this optional heating mode protective means, one should preferably add a heating mode by-pass pressure regulated valve  41 , also referred to as an automatic expansion valve (“AXV”), so as to assist transition from the cooling mode to the heating mode so that the valve opens to a specifically designed interior diameter, as is more fully set forth hereinabove under Summary Of Invention, Number 3, hereinabove, which is incorporated herein by reference.  
         [0208]     The refrigerant then flows through the self-adjusting thermal expansion valve  16 , as well as through a thermal expansion valve by-pass line  17 , which line  17  contains a second single piston metering device  37 , also known as a thermal expansion pin restrictor device. The thermal expansion valve by-pass line  17  and second pin restrictor  38  within the second single piston metering device  37  permits enough refrigerant flow to by-pass the self-adjusting thermal expansion valve  16  so as to enable system operation in the cooling mode at the beginning of the cooling season when the ground surrounding the deep well  7  is very cold, but does not permit enough refrigerant to by-pass the self-adjusting thermal expansion valve  16  so as to materially impair system operation when the ground surrounding the deep well  7  warms up by means of heat rejection during the warm summer months. The optimum sizing of the second pin restrictor  38  within the second single piston metering device  37 , all within the by-pass line  17 , is as explained and set forth under Summary Of Invention, Number 4, hereinabove, which is incorporated herein by reference.  
         [0209]     The refrigerant fluid next flows through the secondary (the double) direct exchange convective heat transfer/refrigerant transport heat exchange tubing segment  99 . Here, the secondary convective heat transfer segment  99  is shown as a distributed array of small refrigerant transport tubes, as such a segment  99  would appear within a concrete, or the like, wall (the concrete wall is not shown, as a concrete wall is well understood by those skilled in the art). As would be well understood by those skilled in the art, any form of DX heat exchange refrigerant transport tubing convective heat transfer means may be used as the secondary direct exchange convective heat transfer/refrigerant transport heat exchange tubing segment  99 , which segment is not limited to the design as shown herein. As heat naturally flows to cold, the heat in the wall would be absorbed by the cooler refrigerant (refrigerant is not shown as refrigerant is well understood by those skilled in the art) flowing through the secondary convective heat exchange tubing  99  within the wall. Thus, the cooler refrigerant would absorb and remove excess heat from the wall, which wall could be at least one of the wall of a structure, a swimming pool, and the like. The wall would, of course, be absorbing heat from the interior air of a structure (not shown herein), from the water within a swimming pool (not shown herein), and/or from any other heat source (not shown herein).  
         [0210]     The warmed refrigerant fluid, having absorbed excessive heat from the secondary convective heat exchange tubing  99 , is transformed into a mostly vapor state, and then flows through an interior located reversing valve  12 , into an accumulator  13 , which catches and stores any liquid refrigerant which has not fully evaporated, and then travels into the compressor  1 . The compressor  1  compresses the cooler refrigerant vapor into a hot refrigerant gas/vapor. The hot refrigerant vapor then travels, by means of the force of the compressor  1 , through the oil separator  30 . The oil separator  30  has a small oil return line  31  that returns oil, which has escaped from the compressor  1 , to the suction line portion  32  of the interior vapor refrigerant transport line tubing  28 , which suction line portion  32  is located prior and proximate to the accumulator  13 , by means of oil return line alternate route A  33 . In an alternative, the oil could be returned, by means of the oil return line  31 , directly into the accumulator  13 , as is shown herein by means of oil return line alternate route B  34 . The refrigerant fluid then travels through the interior located reversing valve  12 , back through the exterior structure wall  24 , through the exterior refrigerant transport vapor line tube  26 , which is surrounded by insulation  3 , and back into the larger diameter un-insulated sub-surface refrigerant vapor transport/heat exchange line tube  11 , which is located below the ground surface  4 , where the geothermal heat exchange process is repeated.  
         [0211]     All above ground surface  4  interior liquid refrigerant transport line tubing  27 , and all above ground surface  4  interior vapor refrigerant transport line tubing  28 , are fully insulated with rubatex, or the like, as is common in the trade, which is well understood by those skilled in the art and, therefore, is not shown herein.  
         [0212]     So as to avoid non-heat conductive air gaps, the remaining interior portion of the heat conductive watertight pipe  5 , located below the ground surface  4 , is filled with a heat conductive fluid mixture of water and anti-freeze  21 . For a similar purpose, the space below the ground surface  4 , between the exterior wall of the pipe  5  and the interior wall of the deep well borehole  7 , is filled with a heat conductive grout  22 , which is in direct thermal contact with the adjacent and surrounding earth  23 .  
         [0213]     An optional low pressure cut-off switch  19  is also shown for a secondary means of compressor  1  shut-off in the event of a refrigerant leak or other low pressure operational event. If used, the low pressure cut-off switch  19  should be set/designed not to shut off the compressor  1  unless there has been a continuous minimum of 10 minutes of system operation under pressure conditions below the requisite minimum. However, even though shown herein, it is preferably unnecessary to employ the use of a secondary low pressure cut off switch  19 , since the compressor&#39;s own internal safety cut-off mechanism will shut the compressor off should it become overheated due to an inordinate period of operation under too low of a refrigerant pressure condition. Thus, in a preferable design, the low pressure cut of switch  19  shown here would simply be eliminated.  
         [0214]     In lightening prone areas, such as the State of Florida, a design improvement to help prevent attracting lightening to underground copper tubing would consist of placing a non-electrical conductive covering  39 , such as a rubber mat or the like, over the top of the well/borehole  
         [0215]     The operation of a low pressure cut-off switch  19 , a compressor  1 , an electric powered fan  15 , a self-adjusting thermal expansion valve  16 , and their requisite and appropriate electrical wiring, as well as the operation of all other system components, are well understood by those skilled in the art and are, therefore, neither shown nor described herein in detail.  
         [0216]      FIG. 22  is a side view of the sub-surface heat exchange tubing  95  within at least one of the concrete  100 , or the like, floor and walls of a swimming pool (not shown herein). The tubing  95  within the concrete  100  would typically have U bends  9 , which U bends  9  should preferably be surrounded with a closed cell insulation  3 . The insulation  3  would prevent the concrete from restricting the copper tubing from expanding/contracting at the U bends  9 , where the most stress would typically occur, as the tubing  95  within the insulation  3  would be free to expand/contract as necessary due to fluctuating temperatures, thereby preventing undue wear and tear on the tubing  95 .  
         [0217]      FIG. 23  is a side view of at least one of the floor and the wall  101  of a swimming pool (not shown), or the like. At least one of under the floor and behind the wall  101  of concrete, or the like, of the pool is a thin plastic sheet  102 . At least one of under and behind the thin plastic sheet  102  is a section of sub-surface heat exchange tubing  95 , such as used in a DX heating/cooling system. At least one of under and behind the tubing  95  is a layer of insulation  3 . The insulation  3  helps insure the bulk of the heating/cooling effect of the DX system, transmitted to the water in the pool (not shown) through the tubing  95 , is not lost into the surrounding ground. The plastic sheet  102 , between the tubing  95  and the concrete  100 , prevents any restriction imposed upon the potential expansion/contraction of the tubing  95  under varying temperature conditions, as well as prevents any exposure of the tubing  95  to any potentially corrosive elements by means of the concrete, or the like, shell of the pool.  
         [0218]      FIG. 24  is a side view of an integrity testing method for the larger O.D. vapor refrigerant transport tubing  11 , and for the coupled  10  smaller liquid refrigerant transport tubing  2  with a vertically oriented DX sub-surface heat exchange system, particularly where the tubing,  2  and  11 , is installed within a borehole/well  7  application.  
         [0219]     Here, a small ball  103 , such as a small plastic ball  103 , is dropped into the top portion  81  of the vapor line  11 , and is allowed to fall, by means of gravity, to the bottom of the tubing,  2  and  11  near the bottom  8  of the well  7 . Next, a container of a pressurized gas  104 , such as dry nitrogen or the like, is connected by means of a pressure hose  105  to the top portion  81  of the vapor line  11  and about fifty pounds of pressure, or the like, is supplied into the top portion  81  of the vapor line  11 . The pressure of the gas will force the small ball  103  up through the smaller liquid line/tube  2 , and eventually into the net  106  at the liquid line outlet  107 . Typically, the ball  103  will exit a three hundred foot deep well within about twelve seconds if there are no restrictions in the tubing,  2  and  11 . If any of the tubing,  2  and  11 , is unduly restricted, the ball  103  will not be able to exit during the integrity test. Preferably, the test will be conducted before the well is grouted (not shown herein as grouting is well understood by those skilled in the art), so that if there is a problem, the tubing,  2  and  11 , can be withdrawn from the well  7  and repaired prior to grouting. This simple test can save thousands of dollars and time, otherwise lost if a refrigerant transport line,  2  and  11 , is only found to be restricted by means of the traditional DX system operational test, after full job completion. A defective/restricted line set,  2  and  11 , after full job completion, can only be corrected by means of installing a complete new replacement line set,  2  and  11 , within a newly drilled and grouted well.