GB2505039A - An air conditioning system for a mine refuge - Google Patents

Abstract

An air conditioning system 10, for a mine refuge, comprising a rigid shell 24 having a door 28; a passive condenser 26 in the shell alongside the door; an explosion proof permissible enclosure 22 disposed in the shell; a first fluid pump (58) disposed in the enclosure; a portable evaporator 18 disposed in the shell; a controller to control the evaporator and a battery array 20. The system may have a purge system including pressurised nitrogen. Also independently claimed is an inflatable chamber having an air lock.

Description

T[TLE OF THE INVENTION Air Conditioner for Refuge Shelter, System and Method

CROS S-REFRENCE TO RELATED APPLICATIONS

[000IJ [his is a non-provisional of U.S. provisional application serial number 61/690,565 filed June 28, 2012.

FIELD OF THE INVENTION

100021 The present invention is related to air conditioners for use with refuge shelters in hanardous environments, such as a mine. As used herein, references to the "present invention" or "invention" relate to exemplary embodiments and not necessarily to every embodiment encompassed by the appended claims.) More specifically, the present invention is related to air conditioners for use with refuge shelters in hazardous environments, such as a mine, where a compressor and a condenser of the air conditioner is located outside of the refuge shelter and an evaporator of the air conditioner is located in the refuge shelter and connected to the compressor and the condenser.

BACKGROUND OF THE iNVENTION

100031 this section is intended to introduce the reader to various aspects of the art that may he related to various aspects of the present invention. The following discussion is intended to provide intbrmation to facilitate a better understanding of the present invention. Accordingly, it should he understood that statements in the following discussion are to be read in this light,

and not as admissions of prior art.

100041 In emergency situations rhere the environment becomes hazardous to people. a refbge shelter provides a safe protected environment from the outside hazardous environment.

Over time, if people must stay in the refuge shelter, steps must he taken to maintain the environment inside the refuge shelter as safe, such as maintain the carbon dioxide level or the temperature in locations where heat is an issue and the temperature cannot he maintain at safe comfortable levels because the outside environment is too warm to cool the refuge shelter.

Furthermore, in certain environments, such as in coal mines, there is risk of expLosion that must he avoided. Consequently, there is a. need for an air conditioner for a refuge shelter that is safe to use in a mine which will avoid the possibility of causing an explosion.

BRIEF SUMMARY OF TI-fE INVENTiON

101)05] The present invention pertains to an air-conditioning system fbr a mine that operates in a mine environment. The system comprises a rigid container having a door, which when open defines an opening. The system comprises a passive condenser disposed in the container alongside the door so when the door is open, the condenser is exposed to the mine environment. The system comprises an explosion proof enclosure disposed in the container.

The system comprises a first fluid pump which pumps fluid disposed in the enclosure. The system comprises a portable evaporator disposed in the container. The system comprises a compressor which pnmps reffigerant. The system comprises a controller in communication with the evaporator which controls the evaporator operation. The system comprises a battery array disposed in the container and electrically connected to the first fluid pump. The system comprises a condenser.

10006] The present invention pertains to a condenser. The condenser comprises a housing. The condenser comprises a bottom portion having a refrigerant coils through which refrigerant flows and bottom fins which contact the refrigerant coils and which cool the refrigerant passing through the coils. The condenser comprises a chimney portion disposed above the bottom portion that draws air into the bottom portion and channels the air up through the chimney portion.

100071 The present invention pcrtatns to a reluige system for protecting users 1-roni a toxic envronment. The system comprises a refuge shelter. The system comprises an air conditioner in communieaeon with the shelter. The air conditioner having an evaporator disposed in the shelter and a shell disposed outside and apart from the shelter. The shell having a condenser and a compressor. The compressor pumping refrigerant to the condenser and the evaporator through hoses that connect the compressor and the condenser and the evaporator together in a fluidic loop' j0008] The present invention pertains to an evaporator. TI-ic evaporator comprises a housing having fins and refrigerant coils in fluidic communication with the fins through which refrigerant flows, there being 4-8 fins per inch.

100091 The present invention pertains to a method For cooling a refuge shelter. The method comprises the steps of connecting refrigerant hoses attached to a compressor and a condenser in a shell to an evaporator in the shelter. The shell disposes outside and apart from the shelter. There is the step of activating the compressor which pumps refrigerant to the evaporator and the condenser.

[00101 The present invention pertains to an inflatable chamber having an airlock, the airlock includes a tube that extends from the chamber's outer surthce into the chamber's interior, the tube having an outer end attached to the outer surFace and an inner end, an outer closure that closes the outer end and an inner closure that closes the inner end.

1001 lj The present invention pertains to a container in an environment. He containe.r comprises an explosion proof enclosure isolated from the environment. The container comprises a purge system in communication with the enclosure.

100121 The present invention pertains to an electricity source. The source comprises a battery having a plate and a case. I he source comprises a terminal formed of a cable which extends out of the ease and is welded to the plate.

BRIEF DESCRIPTION OF TIlE SEVERAL VIEWS OF THE DRAWING [0013J In the accompanying drawings, the preferred embodiment of the invention and preferred methods of pnzcticing the invention are illustrated in which: [0014J Figure 1A shows an XP enclosure of the air conditioner of the present invention.

100151 Figures lB-iD show a layout schematic of the present invention.

100161 Figure 2 is a representation of the refuge system of the present invention.

100171 Figure 3 shows a hattcry of the ptesent invention.

100181 Figures 4A-4D show different views ot' the supastnicture of the enclosure.

(0019] Figure 4E shows the enclosure.

[00201 Figures 5A-5C show different views of an arrestor.

100211 Figure 6 shows the purge feature of the enclosure.

100221 Figure 7 shows the supply hose and the return hose connected to the fan motor.

(00231 Figure 8 shows the evaporator fan assembly.

100241 Figure 9 shows the evaporator.

100251 Figure 10 shows the evaporator.

100261 Figure ii shows the cabLe bundle with the mini air Lock.

100271 Figure 12 shows the cable bundle and the mini airlock.

0028] figure 13 shows the cable bundle und the mini airlock, 100291 Figure 14 shows apod of batteries, 100301 Figure 15 shows the battery system.

[0031 Figure 16 shows (he hydrogen sensor.

[0032] Figure 17 shows the methane sensor.

100331 Figure 18 shows the controi box.

100341 Figure 19 shows the status pane!.

100351 Figure 20 shows the condenser.

100361 Figure 2 I shows the condenser.

100371 Figure 22 shows the condenser.

[00381 Figure 23 shows the intake side of the condenser.

100391 Figure 24 shows the top of the condenser, [0040j Figure 25 shows the removable fins of the condenser.

j0041j Figure 26 is a graph showing battery test results.

100421 Figures 27a-27d show top, side. front and back views, respectively, of the condenser.

DETAILED DESCRIPTION OF THE INVENTION

10043] Referring now to the drawings wherein like reference numerals refer to similar or identical parts throughout the several views, and more specifically to figures lA-ID and 2 thereofi there is shown an air-conditioning system 10 for a mine that operates in a mine environment. The system 10 comprises a rigid shell 24 having a door 28, which when open, defines an opening. The system 10 comprises a passive condenser 26 disposed in the shell 24 alongside the door 28 so when the door 28 is open, the condenser 26 is exposed to the mine environment. The system 10 comprises an explosion proof enclosure 22 disposed in the shell 24, as shown in figure 4E. The system 10 comprises a first fluid pump 58 which pumps fluid disposed in the enclosure 22. The system 10 comprises a portable evaporator 18 disposed in the shell 24. The system 10 comprises a compressor 38 which pumps refrigerant. The system 1 0 comprises a controller 102, as shown in figure 18, in communication with the evaporator 18 which controls the evaporator 18 operation. The system 10 comprises a battery array I 9 disposed in the shell 24 and electrically connected to the lirst fluid pump 58, The system 10 comprises a condenser 26.

[00441 The condenser 26 may he mounted to the door 28 so an opening at the bottom of the housing 146 is disposed at least 1 inch above the ground to allow air to flow thi-ough the opening and to the bottom portion 148 ot' the condenser 26. The condenser 26 may have a chimney portion I 50 having upper fins 156 that guide air flow through them out of the chimney portion ISO and prevents turbulent flow of the air through the condenser 26, as shown in fiires 20-25. The housing 146 may have a rectangular shape. The chimney portion ISO has upper fins 156 that are removable. There maybe 4-8 bottom fins 154 per inch.

[00451 The present invention pertains to a condenser 26. The condenser 26 comprises a housing 15. The condenser 26 comprises a bottom portion 148 having refrigerant coils 152 through which refrigerant flows and bottom fins 154 which contact the refrigerant coils 152 and which cool the refrigerant passing through the coils 152. The condenser 26 comprises a chimney portion 1.50 disposed above the bottom portion 348 that draws air into the bottom portion 148 and channels the air up through the chimney portion 130.

[0046] The present invention pertains to a refuge system 35 for protecting users from a toxic environment, as shown in figures IA and 2. The system comprises a refuge shelter 12.

The system 15 comprises an air conditioning system 10 in communication with the shelter. The air conditioning system 10 having an evaporator 38 disposed in the shelter and a shell 24 disposed outside and apart from the sheltet The shell 24 having a condenser 26 and a compressor 38. The compressor 38 pumping refrigerant to the condenser 26 and the evaporator 18 through hoses that connect the compressor 38 and the condenser 26 and the evaporator iS together in a fluidic loop.

10047] The shelter 12 may have a container 84 and an inflatable tent 82 or chamber that whcn inflated defines a protected cnviromnent for the users and in which the evaporator 18 is disposed. The container 84 having pressurized gas tanks that release breathable air or oxygen into the environment and maintains positive pressure in the inflated tent 82 relative to an atmosphere outside the tent $2.

100481 The present invention pertains to an evaporator 18, as shown in figures 9 and tO.

The evaporator 18 comprises a housing 170 having fins 172 and refrigerant cofls 374 in fluidic communication with the fins 172 through which refrigerant flows., there being 4-8 fins 172 per inch.

100491 The present invention pertains to a method thr cooling a refuge shelter 12. The method comprises the steps of connecting refrigerant hoses 42. 44 attached to a compressor 38 and a condenser 26 in a shell 24 to an evaporator 38 in the shelter. The shell 24 disposes outside and apart from the shelter. There is the step of activating the compressor 38 which pumps refrigerant to the evaporator 18 and the condenser 26.

100501 The present invention pertains to an inflatable chamber 82 having an airlock 72, as shown in figures 2 and 11-13. The airlock includes a tube 83 that extends from the chamber's outer surface into the chambers interior. The tube 83 having an outer end 85 attached to the outer surface and an inner end 87, an outer closure that closes the outer end and an inner closure that closes the inner end.

100511 The outer closure may include an outer drawstring 80 that when pulled closes the outer end and the inner closure includes a zipper 76 at the inner end to open and close the inner end, and an inner drawstring 80 that when pulled closes the inner end.

100521 The present invention pertains to a container in an environment. The container comprises an explosion proof enclosure 22 isolated from the environment. The container comprises a purge system 0 in communication with the enclosure 22.

[9053j The present invention pertains to an electricity source. The source comprises a battery l9 having a plate 35 and a ease 36. The source comprises a terminal 32 formed of a cable 34 which extends out of the case 36 and is welded to the plate 35.

100541 In the operation of the invention, the MSHA Approved 96 hour, 24 VDC Air Conditioning System 10, as shown in figure 1 Aand 2, is battery 21 powered and designed to be used in conjunction with Refuge Shelters 12 created to provide post event refuge in a coal mine environment. It is designed to provide 96 hours of cooling to the shelter occupants in an environment that would otherwise exceed the MS!IA requirement that conditions within Refuge Shelters 12 must remain under 95 degrees apparent during the 96 hour rated service. At the time of deployment, the miners activate the system 10, insert a hose and cable bundle [6, as shown in figures 11-13, into the side of the Refuge Shelter 12, and carry the evaporator 18 cooling unit with them into the shelter 12. After safely inside the shelter, the miners connect the evaporator 18 to the bundle 16 inserted earlier and activate the air conditioning system 10. See U.S. Patent Application 11/903,079 directed to a Refuge Shelter 12; U.S. Patent Application 12/075,002, directed to a scnahher for a Refuge Shelter 12, and U.S. provisional application directed to a refuge shelter; all of which are incorporate by reference herein.

[0055] The siructural shell 24 of the system I 0 is designed to meet the MSHA CER. 30, Part 7 design requirements for Refuge Shelters 12 which require the structure to withstand a 200 millisecond. 15 PSi blast. In order to meet that requirement, this system 10 ha.s a housing of a shell 24 of a Strata Worldwide LLC M10 refuge chamber currently in production. This shell 24 will he modified slightly to house the components of the air conditioning system 10. These modifications include installation of an air tight bulkhead 14 to separate the components designed to he isolated from the niine atmosphere and those components designed to he exposed to the mine atmosphere or those components which will be taken into the Rcthge SheLter 12.

The shell 24 will also be modified 10 accommodate a sled to contain the batteries 21 and explosion proof (XP) enclosure 22, the door 28 mounted condenser 26 as well as control and display panels necessary for system 10 operation.

[0056J One of the difficulties in obtaining approval for a system such as this is that the CFR 30, Part 7 regulations require (hat equipment located "inside" the refuge alternative must be IS (Intrinsically Safe) or permissible while electrical equipment exposed to the mine environment must be IS. The previous interpretation of this regulation rendered design of an air conditioning system 10 virtually impossible due to the level of energy required to remove the heat generated in an occupied refuge shelter or alternative. However, it has been determined that MSH\ is of the opinion that the law also allows Ihr permissible equipment if thc equipment is isolated flow the mine environment. II is that interpretation which has allowed the development of a permissible system due to a unique technique of isolating the system from the mine environment.

100571 The isolation system employed by the MSHA Air Conditioning System 10 uses two means of isolation. First, the components are housed in a gasketed steel structure, previously referred to as the shell 24. This structure is vacuum tested to insure the integrity of the seals, welds, and panels after fabrication. The second means of isolating the components from the mine atmosphere is a purge system 30 that releases nitrogen into the XP enclosure 22 creating a positive pressure environment in the control and power section, compartment 92, thus forcing out any possible contaminants from the mine atmosphere and preventing any ingress of methane. See figure 4. This purge system 30 contains bottle(s) 29, as shown in figure D, of nitrogen located in the shell 24. one of which is dumped just prior to activation while the second bottle is released at a slow trickle over the 96 hour operation of the shell 24. See figures 1 13 ID and 2. Not only does this purge isolate the shell 24 from tile mine atmosphere, the nitrogen creates a nonflammable environment to eliminate any chance of explosion. The two pressurized nitrogen bottles are each connected by tubing to flame arrestor 40 in a wall 112 of the XP enclosure 22. Over pressure of nitrogen in the XP enclosure 22 vents into the interior of the shell 24 through another flame arrestor 40 in the wall 112 of the XP enclosure 22. The purge through tile enclosure 22 into the sheLl 24 is great enough to maintain positive pressure in the shell 24 too. The bulkhead 14 has two pressure relief valves [hr nitrogen gas to escape if pressure in the shell 24 becomes too great. It is this purge system 30 that has created the scenario where MSHA believes the shell 24 and the components disposed in it, including the enclosure 22, may be peimissible instead of Is.

J00581 Although MSHA has determined that the system enclosed in the isolated atmosphere must be permissible, there are a number of unique designs in the system in order to mccl the perniissible criteria.

100591 First, the batten' system 20 must meet a special design as outlined in CER 30, Part 7 which discusses the battery 21 restraint system. required venting, connection systems, etc. The system is designed to meet these criteria. One of the unique aspects of the battery 2 1 connection system is a special battery 21 designed specifically for this application where the battery 21 terminal 32 is a battery cable 34 that is internally welded to the battery 21 plate that then extends approximately 8" out of the battery ease 36. See flgures 3. 14 and 15. This allows a "burned on" connection to the cables that carry the power to the operating components, in accordance with CFR 30 Part 7, Subsection C. [00601 Second, the permissible design requires that all components such as motors, relays, switches, pumps. etc. must be housed within an MSHA approved XP enclosure 22. This enclosure 22 is designed to contain an explosion in the event that explosive gas made its way into the enclosure 22 and was ignited by a spark from a motor, etc. This then creates challenges to move power, fluids, gases, etc. from this Xl' enclosure 22, necessary for cooling and control.

to die Refuge Shelter 12. MSHA rules require that all components exposed to the mine atmosphere be IS. For an air conditioning system 10 to function, it is necessary to remove latent and sensible heat (temperature and humidity) given off by the occupants of the RefUge Shelter 12 and that energy must be expelled into the mine environment. This is accomplished by the evaporation and compression of refrigerant which is circulated from an evaporator 18 located in the refuge back to the compressor 38 and condenser 26 located in the shell 24 via hoses. Moving the refrigerant out of the XP enclosure 22 required the design of a flame arrestor 40 which would both freely pass the refrigerant but would also contain any possible explosion emanating from the XP enclosure 22. This liame arrestor 40. as shown in figures 5A-5D. is also used to pass compressed air to and from the refuge for driving an air motor used to draw air through the evaporator iS, pass refrigerant to and from the XP enclosure 22, venting heat from the XP enclosure 22, as well as for the nitrogen purge. Next, since the components external to an XP enclosure 22 are required to be IS, the condenser 26 that expels the heat removed from the Refuge Shelter 1 2 has been designed to be passive with no fan to force air through the system.

This means the system must be uniquely designed to remove heat via natural convection.

Additionally, the evaporator 18 would be entirely too Large to carry if it were designed to function passively so a motor, powered by air, was chosen to circulate the refuge air through the evaporator 18 for cooling.

[QO6lJ Finally, due to the IS requirements, the control system used to operate the air conditioning system 10 from within the chamber is a liher optic design. This control system is designed to allow the miners to start and stop as well as monitor and reset the system from within the refuge. See figure 18.

[0062J This air conditioning system 10 operates in many ways like a conventional air conditioner. However, the operating environment requires unique features, many of which have already been described. Some additional unique controls include: 100631 Inside the XP enclosure 22, as shown in figures 2 and 4E. is disposed a comoressor 38 which pumps the refrigerant through a refrigerant supply hose 42 to the condenser 26 and from the evaporator 18 through a refrigerant return hose 44 to the evaporator 18. and then hack to the compressor 38 to repeat the cycle. The refrigerant, as it goes through the refrigerant supply hose 42 to the evaporator 18, is exposed to the heat inside the refuge chamber. The refrigerant in the evaporator 18 cools the refuge air as it passes through the evaporator 18. The refrigerant flows from the evaporator 18 through the refrigerant return hose 44 to the compressor 38 then to condenser 26 which removes the heat from the refrigerant that came from the air that was cooled in the evaporator 18 then the cycle is repeated. In this way, refrigerant constantly flows through a loop for cooling. There is in the XP enclosure 22 in communication with the refrigerant supply hose 42 and refrigerant return hose 44 loop, a refrigerant reservoir 46 for providing additional refrigerant as needed. The XP enclosure 22 is about 40' long. 20" high and 17" wide. The walls 112 are 3/8" thick steel and all along the edges are rim bars I I welded in place to the two walls forming the edge. with bolt hole in the rim bars Ill for the cover. See figures 4A-4D.

100641 The overall operation of the cycling of the refrigerant through the evaporator 1 8 and the condenser 26 with the reservoir 46 by the compressor 38 is essentially a standard air-conditioning unit. However, because of the danger of explosion inside a mine, extra care has been taken to respect this dangerous environment and has resulted in. the condenser 26 being completely passive in regard to the air cooling the refrigerant as it flows through the condenser 26. The compressor 38 is inside the XP enclosure 22 because it requires electricity so if there is a spark or some potential fire, the XP enclosure 22 contains the damage explosion or fire can cause. Furthermore. remotely located from the compressor 38 and condenser 26 is the evaporator 18 which is located inside the refuge chamber where the miners reside tbr the cooling of the air.

[0065] All cables or wiring that extends from the inside of the XP enclosure 22 to outside the XP enclosure 22 pass through MSHA approved glands 56. Media flowing through hoses such as the refrigerant, compressed air or atmospheric gasses flowing to or from the XP enclosure 22, pass through flame arrestors 40, The tlane atTest rs.40 dissipate essentially all of flames associated with an explosion or fire inside the XP enclosure 22 so by the time any gas from the the or explosion exits the tlaine arrestor 40, the gas has cooled to a temperature below that which would ignite any methane in the surrounding environment of the mine.

100661 The flame arrestor 40, as shown in figures 5a, Sb and Sc, is a metal, element 48, such as a cylinder that has multiple layers of screens 50 with holes 52 and washers 54 that allow gas or fluid to flow through them, hut slow down the gas or fluid and absorb heat from the gas or fluid as it passes through the series of screens SO until it exits the flame arrestor 40. with the fluid or gas then at a temperature below the temperature needed to ignite methane.

100671 Each hose, such as the supply and return hose, passes through the XP enclosure 22 in two parts. The first part, inside the Xl' enclosure 22, extends from its component source, such as the compressor 38. to the portion of a flame arrestor 40 extending into the XP enclosure 22. The second part, outside the XP enclosure 22. attaches to and extends from the portion of the flame arrestor 40 extending out from the XP enclosure 22, to the ultimate destination, for instance, the evaporator 18. In this way, the fluid in any given hoses safely passes through a wall 112 of the Xl' enclosure 22. For cabling, such as the optical fiber, MSE-IA approved glands 56.

which are well known in the art, are used to allow the cabling or optical fiber to safely extend through the wall 112 of the XP enclosure 22 with essentiauy no risk of explosion or fire escaping through the aperture that has the cabling or ETher.

[0068] The fl and second electric powered air pumps 58, 60 disposed inside the XP enclosure 22, connect to an air supply hose 62 that extends and connects to the evaporator I 8, and an air return hose 64 that extends from the evaporator 18 to the air pumps 58, 60. The air pumps 58, 60 are in parallel so they provide a redundancy in the pumping of air, and provide increased pressure and volume to the air that is pumped. The air supply hose 62 and the air return hose 64 fonn a closed loop so the air inside the closed loop constantly circulates around and around never escaping. This air turns a fan motor 66, such as model Lynx Pro 3 hand piece manufactured by MTT Dentalin. in communication with the loop. The fan motor 66 has a shaft 68 that extends from the fan motor 66 and has a fan 70 at its outer end that is disposed in a fan housing I As the sir in the loop moves through the loop, it turns the air motor, hut cannot escape. As the air motor turns, so does the shaft 68, which in turn rotates the fan 74), which forces air in the Refuge Shelter 12 to pass through the evaporator IS. The air supply hose 62 and the air return hose 64 have self-closing fittings as is well known in the art, so that when the ends of either of the air houses are not connected, but open, the ends automatically close so no air inside the hoses can escape. In this way, the air present during their manufacture becomes trapped inside the hoses and is all that is necessary to be used to circalate through thc air loop and power the air motor to turn the fan 70. The closed ioop is an important design feature in that it prevents introduce contaminants into the refuge chamber.

[0069J The supply and return hoses for the refrigerant and the air, and the control cable 74 from the XP enclosure 22 pass into the refuge chamber through what can be considered a mini airlock 72 in the tent 82, as shown in figures 11-13. The mini airlock 72 is essentially a fabric tube about 36 inches long, that extends from the outer surface of the tent 82 into the interior of the tent 82. The inside end of the fabric tube has a zipper 76 that closes the tube face.

At the surface of the outside of the tent 82, there is a tubular section 78 of material that covers the opening of the lhhric tube. There are also drawstrings 80 at either end of the fabric tube.

Upon deployment of the tent 82, the miners take the hoses and cable from the XP enclosure 22 and extend into the fabric tube. Once the evaporator 18 is carried into the inflated chamber of the Refuge Shelter 12, the zipper 76 at the inside end of the fabric tube is unzipped and the end of the hoses and cable are pulled through and attached to the appropriate connections of the evaporator 18. Once the control cable 74 and hoses are iii place, the draw stiing at either end of the fabric tube is drawn tight essentially fonning a seal at either end around the cable and hoses.

In addition, since positive pressure is maintained inside the chamber of the inflated tent 82, air from the chamber is constantly trying to escape outward from the chamber, which effectively prevents the outside environment from entering into the chamber.

10070] The air conditioning system 10 uses a different type of condenser 26, known as a passive condenser 26, to achieve energy efficient heat rejection. See figures 20-25. Since the AC is powered by a battery 21 hank, there is a finite amount of energy that is available to the system, placing substantial emphasis on energy efficiency. Traditional condensers use fans to transmit air through the condenser 26; however, the passive condenser 26 uses no fairs, and relics on natural convection to reject heat. Fans use energy, and eliminating the tan allows the system to USC less energy to achieve the same result. Furthermore, the passive condenser 26 will he used in a post-explosion coal mine environment, which can be potentially tilled with methane. The danger is that an electrical fan could produce a spark that may ignite the methane within the mine, causing a secondary explosion. Having a condenser 26 that does not utilize a Ian or have any moving parts increases the energy efficiency of the system and ensures safety in a methane environment.

1(1071! The condenser 26, because i.t is passive, is much larger than it otherwise would he if there was air forced about the condenser 26 to cool the refrigerant passing through the condenser 26. 1-lowever, because of the danger of an explosion in a mine, by being a passively operated condenser 26, any risk or threat of explosion from the operation of the condenser 26 is eliminated. The condenser 26 is positioned at the end of the steel shell 24. The end of the shell 24 alongside the condenser 26 has a large door 28 which opens up to the mine environment so the atmosphere of the mine can contribute to tile cooling of th.e refrigerant passing through the condenser 26.

[0072 The anatomy of the passive condenser 26 has some fundamental differences than traditional condensers. First, the passive condenser 26 uses a flue that enhances the natural airflow through tile coils 152 by the principles of buoyancy; hot air rises through the flue, pulling cooler air into the intake of the condenser 26. The flue essentially acts as a duct that forces the hot air to rise through it similar to that of a chimney in a house. Without the flue, the natural air flow at the outlet of the condenser 26 becomes turbulent, disrupting thefl ir flow while reducing the condenser's thermal capacity. This flue is part of the condenser 26 structure, and is not removable, The condenser 26 is bolted to the door 28 of the shell 24. When the door 28 of the shell 24 is opened, the condenser 26 is moved into the environment of the mine and is exposed to the air in the mine. The intake of the condenser should he at least about 3 inches above ground.

100731 Second, the "wetted" portion of the coil, which houses the refrigerant coils 152, is located in the bottom portion 148 of the condenser 26. heating the incoming air, and causing the air to rise through the chimney portion 50. An important characteristic of this portion of the condenser 26 is the fin spacing, Most condensers utilize about I 2-. 14 tins per inch. which is well suited for forced convection condensers. However, the passive condenser 26 has only 4-8 and preferably 6 fins.154 per inch to reduce airflow restriction, which is important due to the passive condenser 26 relying on natural air flow br its heat rejection. This fin 154 spacing is considered quite "open" by industry, and is not typical of standard condcnscrs.

100741 Third. the chimney portion 150 of the condenser 26 has removable fins [56 that provide adjitstability to maximize the condenser's performance. These fins 156 are held in place by sheet metal screws 158 that can be easily removed; alter screw removal the fin 156 can slide out of the top of the condenser 26. The utility of this design is that it provides the option to adjust the condenser's performance by removing fins 156. Each fin 156 segregates the chimney's flow area into smaller chimneys, which hclp reduce eddy currents near the outlet of the chimney portion ISO. However, with the addition of each fin 156, there is more flow restriction in the chimney portion ISO. Having the capability to remove fins 156 provides the adjustability needed to find the correct balance of flow restriction vs. eddy current reduction for each mine environment the system will he placed into.

[0075! The eondense.r 26 may be rectangular. The fins 156 are essential flat sheets of metal. The removable fIns 156 also have a flange 160 at the top that extends from the flat sheet through which the screw 158 extends to hold the sheet in placc Figures 27a-27d show top, side.

front and back views, respectively, of the condcnscr.

j0076) The evaporator 18. as shown in figures 9 and 10, is also unique in its design as compared to commercially available evaporators. The fins arc spaced further apart than typical units, 4-8 tins 172 per inch as compared to [2-14 fins p' inch, in order to prevent moisture saturation and "clogging". The evaporator IS fins 172 may also he coated with a hydrophilic coating or film to assist in shedding of accumulated water droplets. The application of a hydrophilic coating or film onto a piece of metal, such as to [brm a fin, is well known to one skilled in the art.

1(10771 in regard to clogging, when an ajr conditioner is operated in a high moisture environment such as is the condition in a refuge chamber, water droplets accumulate on the fins as the air is cooled. If the fin spacing is oo close, the surface tension of the water causes the water droplets to cling to the fins and accumulate to such a degree that the entire evaporator 18 is completely filled with water and prevents air from flowing through the evaporator 18. By spreading the fins apart, while the "dry air" efficiency of the energy transfer is reduced, the force of gravity overcomes the natural surface tension of water and the water flows out of the evaporator 18. This water sheddin.g process is improved via the use of the hydrophilic coating which inhibits adhesion of water to the fins.

0078 The shell 24 has a bulkhead 14 that defines a compartment 92 that houses the coiidenser 26 and the evaporator 18. as shown in figure 413. The evaporator 18 is removed to the tent 82 by the miners upon deployment.

100791 Inside the XP enclosure 22 is a battery charger 86 that is used to charge the batteries 21 during maintenance. The battery charger 86 has an electrical interface that connects to the electrical power supply present in the mine to receive electricity fiom the mine's power supply to recharge the batteries 2 1.

100801 The battcry charger 86 is connected to the batteries 21 by way of a bank of fuses 8$ arid a master breaker. The batteries 21 are formed into pods 90, with four batteries 21 to a pod 90. As shown in figures 14 and 15. Each battery 21 produces 6 volts. The four batteries 21 in a pod 90 are connected iii series so that a pod 90 produces 24 volts. Each pod 90 is connected in parallel to the hank of fuses 88. so that if one pod 90 becomes damaged it will not affect or stop the power output from the oilier pods 90. Each pod 90 is found in a compartment 92 defined by metal walls, to isolate and protect each pod 90 front the other and also external forces.

[0081 The battery charger 86 is connected to the master breaker and through the bank of fuses and the cables extending from the bank of fuses 88 to each pod 90. When the maintenance mode is activated, electricity flows from the mine electrical system, through the charger, master breaker and bank of fitses 88 to the cables and ultimately to each battery 21 in each pod 90 to charge each battery 1']. A failed ftzse is indicated by an LED readout on the status panel 104, as shown in figure 19. Figure 26 is a graph showing battery test results.

[0082j The air pumps 58, 60 and the compressor 38, shown in figure 4E, receive electricity from the batteries 21 through wiring from batteries 21 to the master breaker and wiring from the master breaker to the air pumps 5%, 60 and the compressor 38 for their respective operation. All breakers have automatic resetting capability so that at any time during operation a breaker is activated, it will he automatically reset so that electricity can continue flowing through it without a miner having to leave the chamber to reset it. In the enclosure 22, there is also a relay 110, a selector switch 112 for mechamcal operation, air manifolds 114, a system charger 116, refrigerant connections 118, airline connections 120, a nitrogen pressure sensor 122 and a thermal breaker 124.

[0083J Extending from each fuse of the bank of fuses 88 is an v1SHA approved cable that connects to each battery 21 in a pod 90. This electrical cable electrically connects to specially designed terminals that extend from each battery 21. Sce figures 3, 14 and 15. The terminals 32 are burned onto the battery 2 [ plates 35 so the connection of the terminal 32 to the battery 2! plate is completely shielded from the atmosphere to eliminate the risk of explosion from the terminal 32 connection. The terminal 32 that extends from the battery 2 1 is soldered to the MSHA cable that connects to the fuse at the XP enclosure 22. The terminal 32 that extends from the battery 21 plate is also ml. MSHA approved, cable. The connection of the terminal 32 cable and the cable from the XP enclosure 22 is made with heat shrink tubing 96 that is soldered to the connection to protect the connection from the atmosphere and thus corrosion over time, which again could create a risk of spark or explosion.

[0084J In regard to the charging and battery system 20, since this is a battery 21 operated system, this system requires a charging system. This is accomplished by thc connection of 120 VAC mine power a.s required (estimated to be on a 3-month interval) to replenish the battery 21 loss due to system monitoring and natural battery 21 discharge rates. Although this system uses AGM gel cell batteries 21 which greatly reduce the incidence of hydrogen off gassing during the charging cycle, the system is monitored by a (5-year rated life) hydrogen sensor 98 that disables the system in the event that hydrogen is sensed. See figure 16. The 6 volt batteries 21 are assembled in pods of 4 and then tise protected to prevent a single battery 21 malfunction from disabling the entire system.

0085J In regard to the auto resetting system, the system is equipped with thermal auto-reset breakers in order to provide a high certainty of operation in a life-dependent environment.

100861 Tn regard to the monitoring system, in addition to Hydrogen monitoring, this system monitors battery 21 charge level and functionality as well as charging cycles (date and duration ol' charge cycle), nitrogen pressure with a nitrogen pressure sensor 94, as well as operational faults. Additionally, this data is recorded by a data logger that may be retrieved via USB port at service intervals to system service system or mine central data system.

100871 Tn regard to the operational modes, the system has 3 modes ol operation. Standby-ready for operation, Service-for charging and data collection and Run-providing cooling for refuge alternative. See figures I B-ID.

(0088j In regard to the remote control 102, see figure I S. the air conditioning system 1 0 is equipped with a fiber optic remote control 102 remote for operation of the air conditioner system from the Refuge Shelter 12. The fiber optic remote control 102 is made by Fiber Switch Technologies. model # SX-921. and is sold by them. On this air conditioning system 10. the miners can start/stop the air conditioning system 10, view system faults, monitor battery 21 bank charge remaining as well as a high level reset to provide maximum opportunity to eolTect potential faults with status panel 104.

F00891 The refrigerant mass flow rate will fluctuate between 60 and 160 Ibs./hr, This fluctuation is due to the compressor's ability to vary its speed based on the system's heat load.

The air to turn the fan 70 is a fixed value, regardless of the number of occupants in the Refuge Shelter 12. The air pumps that drive the fan 70 deliver a combined total of 80 to 110 liters per minute of air, depending on atmospheric conditions. Tins is a closed loop system, and none of this air is intermixed with the refuge air: it is an isolated system and non-adjustable: The condenser 26 is a fixed size, and does not vary based on the number of occupants in the refuge.

The evaporator 18 fan 70 will have a speed range of 1200-1800 rpm. The condenser 26 size can vary tI-2" in each direction. The intake of the condenser 26 should be at least 3" from the ground, which is guaranteed by where it is mounted to the door 28. The condenser 26 is bolted to the door 28 that opens.

100901 Maintenance Schedule and Protocol (00911 Daily 100921 * Visual inspection of the status panel 104 100931 Battery Charge Condition 100941 Nitrogen Pressure 100951 Freon Level [0096J Check Methane Level 100971 Quarterly 100981 * Charge & Collect Data (0099J Turn switch to maintenance position (001001 Visual inspection of status tights 1001011 Cheek H2 [001021. Connect laptop/tablet via fiber optic cable 1001031 Charge system, 6-8 FIr. typ. Charge time 1 00 1041 Record & download system information 1001051 Return switch to standby mode [001061 Annually (001071 Complete System Functionality Test (001081 Activate A/C system (00109J Confirm operation of the A/C system (00110J Replenish Freon levels as necessary [O0i1i Restore unit to standby mode 1001121 Battery Quantities 100113] Low Flow Coil Design [00114] Power Consumption (Amps) [00115] Refrigerant Compressor 33.5 1001161 Air Compressor 4 [001171 Sensors 0.6 [00118J Rethge User Interface 0.6 1001191 Total 40.7 [001201 Batteries 40 OOt21J Selector Switch Modes SFLECTORSWHCE-l SW221 MODES ____ Maintenance Standby (Always Entzaged) Cool item Action item Action Item 1 Action MS226 Methane When tripped CB222 Main Trips at SOA, MS226 Methane When tripped level Switch interlocks out Batten Auto Cools and Level Switch interlocks out Cool High Maintenance Reselling Resets. StatLis High control relay Breaker 50A Indicator Panel CR236 F solid red ___________ _________________ _________________ indicator_light _________________ ___________________ HS200 ilydrogen J After (2?? Min[ PSL224 N2 Status Indicator CB222 Main Control Panel Switch High Delay if no bottles pressure Pane] flash ed Batter Auto Power staths alarm allows switch low indicator light Resetting indication is off interlock i'elay to F Breaker 50A when breaker is engage isolation tripped relays ______ _________________ __________________ ___________________ Blown Fuse When a Batten-Fresh Air Bay "Power On" green Indicators (12 Bank fuse is Control Panel light if main en) IDA Banks 1 blown (FU4OI Status Indicators breaker is made thru 12 thai FU412) a and SW221 is in flashing red Coot indicator light "Cool" green light will show for when cool switch each individual engaged bank "Freon I Compressor Fault" flashing red light when Compress -Control Board shows fault "Air Ptunps F'ault' flashing red light when Air Pumps breaker is tripped -"Battery Life %" 100% all iglits are on, 75% I red 2 amber 1 green is on. 50% 2 amber 1 green is on, 25% amber 1 Green is ____________________ ___________________ ___________________ on,_0% 1 red is on MS226 Methane Status Indicatom-Air Pumps CB237 Auto Reset Level Switch Panel flash icd AP237 & AP238 10 A Breaker High indicator light ________________ _________________ LSLL22S Freon Status ladicatom-Freon Compressor F! Bottle Switch Panel flash red Compressor control board Low Low indicator light -________________ _________________ LSL227 Freon Status Indicator Control Panel Interlocks CR236 1 Bottle Switch Panel flash red Cool Pushbutton Cool main control Low indicator light PBFC'Bl i-clay * HQBQ WO i&iitot Th Data l.oeger Bottles Switch Pressure switch Cool roam control Low. Mc-thanc low relay Level High, Freon Bottle level switch low, I:reoo Bottle level switch low low & Batceiy [00122J Testing Sehethtle'Configuration Test No. Test Sequence Config. Evaporator Evap Flow Condenser Ia Proof test -Capacity lest SRC # XYZ, forced air 400 CFM, Electric fan 51W ft XYZ, forced air lb Proof Lest -Capacity Test SRC ft XYZ, forced air 400 CFM, Electric fan SRC #XYZ. passive 2 Proof Test -Latent heat test SRC 4 XYZ, forced air 400 CEM. Electric fan SRC # xyz. forced air Ii New Coils Test NEW SRC LF F/A 150 CFM, Air Motors 51W # XY., forced air 3lj New Coils lest NEW SEW LF F/A ISO CFM, Air Motors NEW SRC Passive 4 FUll Scalej96 hR. Actual TBD lED FBD S Fill Scale -Tent Test Actual BD TBD 1131) 1001231 Testing Schedule/Configuration (Continued) Condenser Flow Evap/Condenser -Envir. I-li. Batts XL' Box Start Date Coal of lest 600 CEM. Electric Fan Insul. Board/Mock Mine 24 16 none Jan. 2012 Does it work? Baseline capacity.

Natural Insu. Board/Mock Mine 24 16 none Jan. 2012 Gatherpassivc cond data for SRC.

600 CFM. Electric Fan lnsul. Board/Mock Mine 24 16 none Feb. 2012 Evaluate water shedding of coil.

600 CEM, Electric Fan Insul, Board/Mock Mine 24 16 none Feb. 2012 Evaulate LF evaporator design.

Natural Instil, Board/Mock Mine 24 1 lone Feb. 2012 Evaluate LF Evap/Passive Cond combo fED Instil. Board/Mock Mine 96 48 XP Mai-. 2012 TBD ce9a2jT [OO124 Although tile mvenhon has been described in detail in the foregoing embodiments tbr the purpose of illustration, it is to be understood that such detail is sold> ror that purpose and that variations can be made therein by those skifled in the art without departing from the spirit and scope of the invention except as it may be described by the following claims.

Claims (18)

1. CLAiMS 1. An air conditioning system for a mine that operates in a mine environment comprising: a rigid shell having a door. which when open defines an opening; a i'' condenser disposed in the shell alongside the door so when the door is open. the condenser is exposed to the mine environment; an explosion proof permissible enclosure disposed in the shell that is isolated from the mine; a first fluid pump which pumps fluid disposed in the enclosure; a portable evaporator disposed in the shell; a compressor which pumps refrigei-ant; a controller in communication with the evaporator which controls the evaporator operation; and a battery an-ay disposed in the shell and electrically connected to the first fluid pump.
2. 2. The system of claim I wherein the condenser is mounted to the door so an opening at the bottom of the condenser is disposed at least 1 inch above the ground to allow air to flow through the opening and to a bottom portion of the condenser.
3. 3 The system of claim 2 wherein the condenser has a chimney pofl.ion having upper tins that guide air flow through them out of the chimney portion and prevents turbulent flow of the air through the condenser.
4. 4, The system of claim 3 wherein the condenser is rectangular shaped.
5. 5. The system of claim 4 wherein the chimney portion has upper tins that are removable.
6. 6. The system of claim 5 wherein the bottom portion of the condenser has 4-8 bottom tins per inch.
7. 7. The system at' claim 6 including a purge system to isolate the enclosure from the mine.
8. 8. The system of claim 7 wherein the purge system includes a pressurized nitrogen bottle disposed in the container in fluid communication with the enclosure which provides nitrogen gas to the enclosure and maintains positive pressure in the enclosure.
9. 9. The system of claim 8 including a liame arrestor disposed in a vail of the enclosure, and tubing connected to the nitrogcn bottle and the ai-restor through which the nitrogen gas flows from the nitrogen bottle through the arrestor into the enclosure.
10. 10. A condenser comprising: a housing; a bottom portion having a refrigerant coils through which refrigerant flows and bottom tins which contact the refrigerant coils and which cool the refrigerant passing through the coils: and a chimney portion disposed above the bottom portion that draws air into the bottom portion and channels the air up through the chimney portion.
11. 11. A refuge syslem for protecting users from a toxic environment comprising: a refuge shelter: and an air conditioning system in communication with the shelter, the air conditioning system having an evaporator disposed in the shelter and a shell disposed outside and apart from the shelter, the shell having a condenser and a compressor, the compressor pumping refrigerant to the condenser and the evaporator through hoses that connect the compressor and the condenser and the evaporator together in a fluidie loop.
12. 12. The system of claim ii wherein the shelter has a container and an inflatable tent that when inflated deBnes a protected environment for the users and in which the evaporator is disposed, the container having pressurized gas tanks that release breathable air or oxygen into the environment and maintains positive pressure in the inflated tent relative to an atmosphere outside the tent.
13. l3. An evaporator comprising: a housing having fins and refrigerant coils in tluidic communication with the fins through which refrigerant flows, there being 4-8 hns per inch; a fan disposed in the housing; arid a gas powered motor disposed in the housing to operate the fans.
14. 14, A method for cooling a refuge shelter comprising the steps o1 connecting refrigerant hoses attached to a compressor and a condenser in a shell to an evaporator in the shelter., the shell disposes outside and apart from the shelter: and activating from the shelter the compressor in the shell which pumps refrigerant to the evaporator and the condenser.
15. 15. An inflatable chamber having an airlock, the airlock includes a tube that extends from the chamber's outer surface into the chamber's interior, the tube having an outer end attached to the outer surface and an inner end, an outer closure that closes the outer end and an inner closure that closes (he inner end.
16. 16. The chamber of claim 15 wherein the outer closure includes an outer drawstring that when pulled closes the outer end and the inner closure includes a zipper at the inner end to open and close the inner end, and an inner drawstring that when pulled closes the inner end.
17. 17. A container in an environment comprising: an exp'osion proof enclosure isolated from the enviromnent; and a purge system in communication with the enclosure.
18. 18. An electricity source comprising: a battery having a plate and a case; and a terminal formed of a cable which extends out of the case and is welded to the plate.