Patent Publication Number: US-2006003276-A1

Title: Hydrogen gas fireplace

Description:
FIELD OF THE INVENTION  
      The present invention generally relates to fireplaces, and more specifically relates to fireplaces that use hydrogen as a source of fuel.  
     BACKGROUND OF THE INVENTION  
      The use of hydrogen as a source of fuel has gained increased popularity in recent years as technology related to the production of hydrogen has improved and the public perception of safety related to hydrogen has gradually changed. Hydrogen fuel has many benefits and advantages over other commonly used sources of fuel. For example, combusting petroleum products (e.g., natural gas and liquid propane) and fibrous products (e.g., wood) in a heating appliance generates harmful gases such as carbon monoxide (CO) that must be exhausted. Providing exhaust vent systems for a heating appliance adds significant cost, time and space requirements when installing the heating appliance. In contrast, the byproducts of generating and combusting hydrogen are oxygen (O 2 ) and water (H 2 O). These byproducts are not only safe for the environment, but are also desirable products that can be used for alternative purposes in a beneficial way. Thus, an exhaust system is not required when combusting hydrogen.  
      An associated advantage of combusting hydrogen relates to proper venting of an open front fireplace structure. Open front fireplaces typically have a certain amount of the combustion gases that spill out of the fireplace front, especially under conditions of back draft in the fireplace exhaust vent or negative pressure in the living space. Thus, the use of open front fireplaces for combusting typical fuels (e.g., petroleum based and fibrous products) has become very limited in the recent past due in part to higher air quality standards and an increases awareness of safety issues related to combustion gases. As noted above, byproducts of combusting hydrogen do not have to be exhausted, thus removing limitations to the use of an open front fireplace.  
      Another advantage with using hydrogen as a source of fuel relates to the relative simplicity of generating hydrogen fuel itself. Water is commonly used as a basis for hydrogen fuel production. In one example, sodium hydroxide is mixed with aluminum and water; the chemical reaction of which produces hydrogen gas. Another example hydrogen production system is an electrolyzer that generates hydrogen by charging water particles to create a polarity and then splitting the water particles with a charged proton exchange membrane. Many other types of hydrogen production are known or are being developed for use.  
      The use of hydrogen as a fuel also has some disadvantages. One disadvantage relates to storage of hydrogen and delivery of hydrogen to an end user. Unlike natural gas and other petroleum based and fibrous materials that are used for energy, there is presently no infrastructure or system established for mass production and/or delivery of hydrogen fuel to an end user. As a result, the hydrogen fuel must be generated on site or delivered in relatively small quantities. Two example storage methods for hydrogen fuel are a pressurized tank in which the hydrogen fuel displaces water also contained in the tank, and a metal hydride foam which when charged with one polarity is able to retain hydrogen and when charged in the opposite polarity releases the hydrogen.  
      The use of hydrogen as a fuel to create a decorative flame or to produce heat in a heat generating appliance also has some disadvantages. One disadvantage relates to the appearance of combusting hydrogen as a decorative flame. Combusting hydrogen is relatively colorless and the flame is relatively hot compared to flames of other known combustible materials. Also, the flame appearance is linear and involves very little movement of the flame itself (flame movement being known generally as “flicker”). Decorative flames typically have a yellow or orange tint and flicker significantly at any flame size.  
      Structures and methods relating to combusting hydrogen in a heating appliance that address these and other disadvantages of combusting hydrogen would be an advance in the art.  
     SUMMARY OF THE INVENTION  
      The present invention generally relates to fireplaces, and more specifically relates to fireplaces that use hydrogen as a source of fuel. One aspect of the invention relates to a gas fireplace that includes a combustion chamber enclosure, a burner, and a flame enhancement member. The combustion chamber enclosure defines a combustion chamber. The burner is disposed in the combustion chamber and defines apertures positioned to provide hydrogen gas to a surface of the burner for combustion. The flame enhancement member is positioned relative to the surface of the burner to engage the combusting hydrogen thereby improving visibility of the combusting hydrogen.  
      Another aspect of the invention relates to a burner for use in a hydrogen burning appliance that includes a gas enclosure defining a gas distribution chamber and a gas aperture, a burner having a combustion surface, a hydrogen gas source coupled to the gas enclosure, and a flame enhancement member positioned in a path of the combusting hydrogen. The hydrogen gas source supplies hydrogen gas to the gas chamber for distribution to the gas aperture for combustion of the hydrogen gas at the combustion surface.  
      A further aspect of the invention relates to a method for generating a visible hydrogen flame. The hydrogen flame is provided in a gas enclosure that defines a gas distribution chamber and a combustion surface having a gas aperture formed therein. The method includes supplying hydrogen gas to the gas distribution chamber, passing the hydrogen gas out of the gas aperture, combusting the hydrogen gas at the combustion surface, and passing the combusting hydrogen gas through a flame enhancement member to alter a color of the combusting hydrogen gas.  
      Another aspect of the invention relates to a fire display assembly that includes a burner, a flame enhancement member, and a support platform. The burner defines apertures positioned to provide hydrogen gas to a surface of the burner for combustion. The flame enhancement member is positioned relative to the surface of the burner to engage the combusting hydrogen thereby improving visibility of the combusting hydrogen. The platform is configured to support the burner and flame enhancement member from vertically beneath the burner and flame enhancement member. The burner is open to ambient air on all sides such that the fire display assembly is configured as an open fire pit.  
      The above summary of the present invention is not intended to describe each disclosed embodiment or every implementation of the present invention. Figures in the detailed description that follow more particularly exemplified embodiments of the invention. While certain embodiments will be illustrated and described, the invention is not limited to use in such embodiments. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      The invention may be more completely understood in consideration of the following detailed description of various embodiments in the invention and in connection with accompanying drawings, in which:  
       FIG. 1  is a front perspective view of an example fireplace that includes a burner assembly configured to combust hydrogen to produce flame;  
       FIG. 2  an exploded view of the fireplace shown in  FIG. 1  illustrating the burner assembly as a separate unit and the burner assembly coupled to a hydrogen fuel source;  
       FIG. 3  is a perspective view of the tube burner shown in  FIGS. 1 and 2 ;  
       FIG. 4  is a top view of the tube burner shown in  FIG. 3 ;  
       FIG. 5  is a top perspective view of a pan-shaped burner according to principles of the present invention;  
       FIG. 6  is an exploded view of the pan-shaped burner shown in  FIG. 5 ;  
       FIG. 7  is a side view of the pan-shaped burner shown in  FIG. 5 ;  
       FIG. 8  is a top perspective view of an example burner assembly that is configured to combust hydrogen to produce a flame according to the principles of the present invention;  
       FIG. 9  is a side view of the burner assembly shown in  FIG. 8 ;  
       FIG. 10  is a front view of the burner assembly shown in  FIG. 8 ;  
       FIG. 11  is a front perspective view of an example of ceramic molded burner according to principles of the present invention.  
       FIG. 12  is a top perspective view of a tube burner assembly with a contoured flame enhancement member coupled thereto according to principles of the present invention;  
       FIG. 13  is a top view of another example pan-shaped burner having a flame enhancement member formed thereon according to principles of the present invention;  
       FIG. 14  is a side view of the burner shown in  FIG. 13 ;  
       FIG. 15  is a side view of another example fireplace that includes a smoke simulation assembly according to principles of the present invention;  
       FIG. 16  is a front perspective view of an example open fire display assembly according to principles of the present invention;  
       FIG. 17  is a side view of another example fireplace that includes a blower according to principles of the present invention;  
       FIG. 18  is an example circuit diagram illustrating components of an example ignition system for a hydrogen burner; and  
       FIG. 19  is a process diagram illustrating an example operation method according to principles of the present invention. 
    
    
      While the invention is amenable to various modifications and alternate forms, specifics thereof have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the invention is not limited to the particular embodiments described. On the contrary, the invention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.  
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
      The present invention generally relates to fireplaces, and more particularly relates to fireplaces that use hydrogen as a source of fuel. The present invention also relates to methods of generating a visible hydrogen flame, methods of generating, storing, and delivering hydrogen to a hydrogen burner in a fireplace, and other methods and structures related to the use of hydrogen as a fuel in heating appliances such as fireplaces.  
      While the example embodiments of the present invention provided below are described in connection with example fireplaces, the present invention may be applicable to other systems or apparatuses such as furnaces and stoves. Principles of the present invention may be embodied in retrofit configurations that can be applied to existing fireplaces. Further, common venting systems and fireplace configurations such as a direct vent, a universal vent, a B-vent, a horizontal/vertical-vent, a dual direct vent, and a multisided unit having two or three glass panels as combustion chamber side panels may be used to exhaust unwanted byproducts (heat, water (H 2 O) or oxygen (O 2 )) of combusting hydrogen fuel. Such common venting systems and fireplace configurations may include an adjustable baffle member (not shown) that controls the flow of combustion byproducts into a venting system as desired (e.g., exhausting heat and water byproducts during the warmer summer months and not exhausting heat and moisture byproducts during colder, dryer winter months). While the present invention is not so limited, an appreciation of various aspects of the invention will be gained through a discussion of the examples provided below. Principles of the present invention may be best recognized in applications in which the combusting hydrogen is viewable as a decorative flame.  
      As used herein, a “combustion chamber” may include any structure that at least partially encloses a space in which a flame, simulated flame, or flame-related effect is generated by, for example, combusting material or generating a flame-related effect such as sound or light. A “combustion chamber” may be defined by one or more panels that permit viewing through the panel. A “combustion air enclosure” is defined as any enclosure that defines a chamber for holding combustion air for use in the combustion chamber. A “combustion fuel enclosure” is defined as any enclosure that defines a chamber for holding combustible fuel. A “flame enhancement member” is any solid material such as, for example, metal, metal alloy, or other material that alters a property of the combusting hydrogen. In one example, the flame enhancement member is a metal member that alters the visible color of the combusting hydrogen by, for example, ionizing the combusting hydrogen.  
      One example fireplace assembly  10  that includes features related to combustion of hydrogen is described and illustrated with reference to  FIGS. 1-3 . Fireplace  10  includes an outer enclosure  12 , a combustion chamber enclosure  14 , a burner assembly  16 , a grate  18 , and a fuel source  19 .  
      The outer enclosure  12  may include an exhaust aperture  20 , an intake vent  22 , and an exhaust vent  24 , although some or all of these features may not be required because of the limited combustion air requirements and the clean combustion byproducts of combusting hydrogen. The combustion chamber enclosure  14  includes rear, bottom, side, and front panels  30 ,  32 ,  34 ,  36 , which together define a combustion chamber  38 , wherein combustion of hydrogen occurs for the generation of heat. The panels of the combustion chamber enclosure  14  may include materials such as, for example, sheet metal, molded fiber material, or a combination of these materials. In one embodiment, the combustion chamber enclosure is constructed of a moldable material like that described in U.S. patent application Ser. No. 09/781,148, incorporated herein by reference.  
      Typically, the combustion chamber enclosure  14  is positioned within the outer enclosure  12  such that a plenum is defined there between in which air drawn in through the intake vent  22  can be heated by heat emanating from the combustion chamber  38  through the panels  30 ,  32 ,  34 ,  36 . The heated air may be exhausted out of the exhaust vent  24  back into a living space, or vented to a remote location. Preferably, the combustion chamber enclosure is open at a front surface thereof to provide a more realistic fireplace setting. Because the byproducts of hydrogen combustion pose no health risks, the venting issues common to known open front fireplaces are not relevant; with the possible exception of venting heat.  
      A front panel (not shown) made of a clear material that provides viewing of the combustion chamber  38  while sealing the combustion chamber  38  may be included in some embodiments. The addition of a front panel (either a fixed or removable panel) may improve safety and help control venting of the combustion byproducts. Still further embodiments may include modified panels of the combustion chamber enclosure  14  to alter the flow of air and combustion products into and out of the combustion chamber  38 . For example, one embodiment may include a bottom panel  32  having a plurality of apertures formed therein and the fireplace includes a blower or a plurality of blowers positioned in fluid communications with the apertures so as to provide either a stream of fresh air into the combustion chamber or to provide a suction force that draws combustion products and heat out of the combustion chamber.  
      The burner assembly  16  includes a valve  40 , a first fuel line  42 , a base  44 , an ignition/pilot system  46  having a thermopile  48  and a pilot burner  49 , a tube burner  50 , a flame enhancement member  52 , and a second fuel line  54 . The first fuel line  42  is coupled to the fuel source  19 , and the second fuel line  54  couples the valve  40  to the tube burner  50 . Typically, the fuel source  19  provides hydrogen gas for combustion. Alternatively, mixtures of hydrogen gas and other combustible gases, such as natural gas and propane, can be burned within the combustion chamber enclosure. The amounts of hydrogen and other gases can be metered, regulated, or prepared to modify the heat of combustion and visual appearance of the flame.  
      The fuel source  19  can be placed within the plenum created between the combustion chamber enclosure  14  and the outer enclosure  12 . Alternatively, the fuel source  19  can be located in remote location and the hydrogen gas can be supplied for combustion by a supply line. One hydrogen generating fuel source is an electrolyzer. An exemplary electrolyzer can be obtained from HYDROGENICS located in Mississauga, Ontario, Canada.  
      As shown in  FIG. 3 , the tube burner  50  includes a plurality of apertures  56  sized and configured for passing hydrogen fuel from the second fuel line  54  to an outer surface of the tube burner  50  for combustion when ignited by the system  46 . The burner  50  also includes a mounting bracket  58  for mounting the tube burner to the base  44  and the second fuel line  54 . The valve may be any valve that is suited for controlling the flow of hydrogen, such as, for example, the valve shown and described in U.S. Pat. No. 6,520,199 and U.S. patent application Ser. No. 10/788,751, which patent and application are incorporated herein by reference in their entirety. The burner  50 , although shown having a linear, cylindrical shape, may be shaped with contours and different cross-sectional shapes in other embodiments.  
      The ignition system  46  may be any system or device that ignites the hydrogen fuel to begin combustion of hydrogen at the burner  50 . The thermopile  48  is designed to recognize the presence of combusting hydrogen fuel. When the thermopile  48  recognized the presence of combusting hydrogen via the pilot burner  49 , then the ignition system signals the valve  40  to deliver hydrogen fuel to the burner  50  for combustion. When the thermopile does not recognize the presence of combusting hydrogen, it will stop the flow of gas through the valve. Additionally, a signal can be sent to the electrolyzer to stop the production of hydrogen and protect the closed valve from damage due to pressure.  
      A hydrogen flame does not conduct electricity sufficient for known flame conduction and rectification systems to operate properly. Known thermocouples respond relatively slowly, which would make a hydrogen flame sensing method that uses a known thermocouple dangerous because a potentially dangerous amount of hydrogen could accumulate before the thermocouple responds. The use of example circuitry  900  shown in  FIG. 18  with the thermopile  48  makes it possible to amplify and differentiate the voltage measurements of thermopile  48  so that as the voltage increases, a large output is produced that is easier to recognize and respond to. Once the output of the thermopile  48  is no longer increasing, the steady state gain produces the large output. If the hydrogen flame being monitored by thermopile  48  extinguishes, the output of the thermopile starts to decrease and the differentiated signal drives the output low, even though the thermopile may still be very hot.  
      The example circuit  900  may function as follows: Resistors R 2 , R 1  and amplifier IC 1 A produce a steady state gain of 2. Capacitor C 1  and R 2  with the amplifier IC 1 A form a differentiator, the maximum gain being limited by C 2 . Capacitors C 3 , C 2  and C 4  act as filters, decreasing the sensitivity to noise ratio, which is advantageous because differentiation is an inherently noisy process. Transistor Q 1  pulls the diode D 1  to ground and R 4  provides a light load so that flame sensing circuitry (not shown) of ignition/pilot system  46  senses a flame. The other half of the amplifier IC 1 A is not used, but is merely coupled so as to minimize the current drain. A standard thermocouple could also be used if the gain of the circuit were increased. Such a thermocouple could also be adapted to drive the valve  40  in other configurations with different components of the ignition/pilot system  46  removed or modified.  
      Referring again to  FIGS. 1-4 , the flame enhancement member  52  is positioned adjacent to the plurality of apertures  56  such that a flame of combusting hydrogen at the surface of the tube burner  50  passes through or at least contacts the flame enhancement member  52 . The flame enhancement member  52  may be positioned in contact with the tube burner or may be slightly spaced apart from the tube burner outer surface depending on such considerations as the material of the tube burner and the flame enhancement member, the volume of hydrogen flowing through the openings  56 , and the relative flame size and desired flame effect.  
      The flame enhancement member  52  may include a porous structure that permits passage of combusting hydrogen through the material. Some example porous structures include foam, mesh, and screen structures. Other material structures besides foam structures may also be used so long as the combusting hydrogen can pass through, around or otherwise in contact with the flame enhancement member such that the color of the combusting hydrogen is at least partially changed as a result of contact between the combusting hydrogen and the flame enhancement member. Member  52  may include metals, metal alloys, and other substances that alter an appearance of the flame by, for example, ionizing the combusting hydrogen due to the intense heat generated by the combusting hydrogen to provide coloring of the resulting flame. In one example, the use of a flame enhancement member  52  that includes nickel provides yellow coloring of the flame. Some further example materials that generate specific colors when contacted by a flame are listed in the following Table I.  
                   TABLE I                       Materials   Color                  lithium compounds-masked by barium or sodium   Carmine       strontium compounds-masked by barium   Scarlet or Crimson       calcium compounds-masked by barium   Yellow-Red       sodium compounds   Yellow       zinc   White-Green       copper compounds, other than halides; thallium   Emerald       phosphates   Blue-Green       antimony and NH 4  compounds   Faint Green       barium, molybdenum   Yellow-Green       lead, selenium, bismuth, copper chloride and other   Azure       copper compounds       arsenic and some of its compounds   Light Blue       CuBr 2 , antimony   Greenish Blue       potassium, rubidium, cesium   Purple-Red       cupric chloride   Blue       calcium chloride   Orange       magnesium ribbon   White Sparks       iron fillings   Yellow Sparks       lithium chloride   Red       sodium chloride   Yellow                  
 
 In order to produce a realistic appearing flame or at least a flame that more closely resembles a combusting fibrous material (e.g., wood), the combusting hydrogen is preferably changed to yellow, orange, or red color, or a combination of these colors. 
 
      To further enhance the “realistic” appearance of the combusting hydrogen, a blower may be positioned in proximity to the burner to provide a flow of air that alters a position of the combusting hydrogen flame. Such a blower may be modulated thereby providing a modulated air flow that contacts the combusting hydrogen to give the appearance of a modulating flame, which is also common to a flame emanating from a burning fibrous product such as wood.  
      An example fireplace  800  that includes a blower  804  is shown and described with reference to  FIG. 17 . Fireplace  800  includes a combustion chamber enclosure  814  in which the blower  804 , a stand  806 , a log set  810 , a burner  850  and a stand  806  are positioned. A fuel source  819  is coupled to the burner  850  via a fuel line  842 . A flame  851  generated by the burner  850  may be contacted with a first air stream  802  generated by the blower  804  to alter a position, size, shape, or other physical feature of the flame  851 . Heat and other combustion byproducts of the fuel combusted by burner  850  may be moved out of the combustion chamber enclosure  814  by the second air stream  803 . The second air stream  803  may be directed out of an open front of the combustion chamber enclosure  814 , or may be directed into a plenum or vent system of the fireplace  800 .  
      The blower  504  may be controlled by a controller (not shown) that modulates or otherwise controls the flow of air from the blower  804 , thereby further altering the flame  851 . Control of the blower  504  may be synchronized with other controlled features of the fireplace  800  such as the flow of fuel from the fuel source  819  to the burner  850 , lighting (not shown) and sound (not shown).  
      A blower may also be used as part of a heat recovery system such as the heat recovery system shown and described in U.S. Pat. No. 6,550,687, which is incorporated herein by reference in its entirety. A heat recovery system associated with the fireplace  10  may also include a moisture recovery and oxygen recovery system (water and oxygen being the by products of hydrogen combustion) (system not shown), which products can be recycled and reused by the fireplace  10  or for other desired purposes.  
      The fuel source  19  may be any hydrogen generating system that is capable of generating hydrogen fuel and is sized to be disposed within the outer enclosure  12 , for example, below the combustion chamber enclosure  14 . In other embodiments, the fuel source  19  may be positioned at a remote location from the fireplace  10  and fuel source  19  is coupled to the burner assembly via the first fuel line  42 . In still further embodiments, the fuel source  19  and burner assembly  16  may be portable devices that can be moved from one heating appliance to another or function separate from a heating appliance such as, for example, as a fire pit or a fire display device in an outdoor area or within a building structure.  FIGS. 8-9  illustrate an example portable burner assembly  216  that is described in further detail below. In still further embodiments, the fuel source  19  represents a fuel distribution system such as is commonly used for distribution of natural gas in urban areas.  
      Certain features of the burner assembly  16  may be interchangeable with alternative features that have different designs and functions. For example, the tube burner  50  and flame enhancement member  52  may be replaced with the example pan burner  116  shown in  FIGS. 5-7 . The pan burner  116  includes first and second supports  118 ,  120 , an input member  142  having a mounting bracket  143 , a pan burner  150  that includes a gas distribution enclosure  151  having a plurality of apertures  156  formed on a surface thereof, and a flame enhancement member  152  positioned adjacent to the plurality of apertures  156 . The “pan” structure of the burner  150  provides a large surface area over which a pattern of apertures  156  may be formed to more closely simulate the burning of a log within the combustion chamber  38  as compared to the tube burner  50  described above. In other embodiments, the pan member  150  may be sized or shaped to simulate the size and shape of a log or stick. Likewise, the flame enhancement member  152  may also be sized and shaped to correspond to the size and shape of at least a portion of the pan portion  150  or a log set (e.g., log set  610  shown in  FIG. 15 ), or may be separately formed and shaped as desired to create a different desired visual effect. Shaping of the flame enhancement member  152  may be performed using any desired methods such as, for example, bending, stamping, casting, molding, spraying, etc. In one example, the flame enhancement member includes a log shape and is configured as a depletable log that is reduced in size as a result of contact with the combusting hydrogen to alter an appearance of the combusting hydrogen flame.  
      An example of a shaped flame enhancement member is shown in  FIG. 12  with reference to the burner assembly  416  that includes a tube burner  450 , a shaped flame enhancement member  452  that is coupled to the tube burner with a mounting bracket  453 , and a mounting bracket  458  for mounting the tube burner  450  to a source of hydrogen fuel. The shaped flame enhancement member  452  has a semi-circular cross section that substantially matches the outer contour of the tube burner and surrounds a plurality of apertures in the outer surface of the tube burner (e.g., see apertures  56  in  FIG. 3 ).  
      Another example burner assembly  316  is shown with reference to  FIG. 11 . Burner assembly  316  includes a molded ceramic pan burner  350  having an upper surface that includes a plurality of contours, and a flame enhancement member  352  that is molded to the upper surface  351 . A plurality of apertures  356  are shown for purposes of reference only to illustrate that the flame enhancement member  352  would be positioned vertically above the apertures  356 . With the flame enhancement member  352  in proper position, the plurality of apertures  356  would not be visible from the view shown in  FIG. 11 . Example molded ceramic burner structures are shown and described in U.S. Published Application No. US-2004-0058288-A1, which application is incorporated herein by reference in its entirety. The burner  350  may be made of other inorganic materials that are compression or vacuum molded or cast as the case may be. As noted above, the flame enhancement material  352  may also be molded or otherwise formed directly on the upper surface  351  of the burner  350 , or may be adhered, fastened, or otherwise coupled to the burner  350  adjacent to and preferably covering the apertures  356  so as to be in the flow path of combusting hydrogen.  
      Another example pan burner  550  that includes a molded flame enhancement member  552  is shown with reference to  FIGS. 13 and 14 . The burner assembly  516  includes an input member  542  having a mounting bracket  543  as well as supports  518  and  520  that maintain the burner  550  in a predetermined position. The molded flame enhancement member  552 , as well as all other burner enhancement members described herein, may include contours, shapes, elevations, coloring, texture, and other features (e.g., fiber wool and other simulated ember members) as desired to provide a certain aesthetic effect and appearance.  
      Referring now to  FIGS. 8-10 , the stand alone burner assembly  216  includes a pan burner  250 , first, second and third supports  218 ,  219 ,  220  (a fourth support being not clearly shown), a valve assembly  240 , a first fuel line  242 , a input member  243 , a pilot/ignition system  246  coupled to a pilot system platform  247 , a second fuel line  254 , and a plurality of apertures  256  formed in the pan burner upper surface  250 . The supports  218 ,  219 ,  220  provide sufficient support such that the assembly  216  can function as a standalone unit that may be movable for use in any desired location (as noted above). The first fuel line  242  may be coupled to a fixed or portable fuel source such as fuel source  19  described above with reference to  FIG. 2 . The assembly  216  may also include a flame enhancement member  252  that is coupled to an upper surface  251  (see  FIG. 10 ) for the coloring combusting hydrogen as described above.  
      The stand alone burner assembly  216  may be used without an exhaust ventilation system as is commonly required for typical decorative fire display devices burning known combustion products such as natural gas and fibrous products. As a result, the assembly  216  could be used in an open room of an enclosed living space without any danger of pollution or the release of harmful substances into the room air. Combusting hydrogen may actually provide an added benefit of increasing the moisture content of the room air and oxygenizing the room air for improved living comfort and health of those residing with the living structure. Alternatively, the oxygen byproduct can be delivered to the combusting hydrogen to aid in combustion. A system or device can be utilized that meters or regulates the amount of oxygen being directed to the combusting hydrogen gas.  
      Referring now to  FIG. 15 , an example fireplace  600  is shown including a smoke simulation system. Fireplace  600  includes a combustion chamber enclosure  614  in which a stand  606 , a log set  610 , a burner  650 , and a smoke simulator system  660  are positioned. A fuel source  619  provides fuel to the burner  650  via a fuel line  642 , whereby the burner  650  combusts fuel to generate a flame  651 . The smoke simulator system  660  includes a water supply  662  in the form of, for example, a pool of water, and first and second transducers  664 ,  666 . The first transducer  664  may be configured to vaporize water from the water supply  662  thereby generating streams of water vapor  668  that can rise separate from or intermixed with the flame  651 . The vapor streams  668  may be colored by light generated by a light source  608  that directs light onto the vapor stream and/or the flame  651 . The vapor streams  668  may provide the appearance of smoke rising for the flame  651  and log set  610  to improve the aesthetics of the fireplace  600 . The second transducer  666  may be used to create movement in the water supply  662  that is viewable to an observer and gives the appearance of an ember bed when the water supply  662  is colored by, for example, the light source  608 , flame  651 , or coloring in the water itself. In some embodiments, the burner  650  and smoke simulator  660  may be integrated into a single unit.  
      The light source  608  is positioned vertically below the smoke simulator  660  in  FIG. 15 , but may be positioned at any location in the combustion chamber enclosure  614  in other embodiments. The fuel source  619  is shown in  FIG. 15  at a position below the burner  650 , but may be positioned at any location adjacent to or at a location remote from the burner  650 . Preferably, the fuel source  619  provides a source of hydrogen fuel to the burner  650  for generation of the flame  651 . In some embodiments, the fuel source may be an electrolyzer that generates hydrogen fuel for the burner  650  and water for the water supply  660 . The stand  606  may provide support for some features of the features of fireplace  600 , or the stand  606  may be removed so that a floor panel  601  of the combustion chamber enclosure  614  provides the necessary support.  
      Referring now to  FIG. 16 , an example open pit fire display  700  is shown. The display  700  includes a support platform  714 , a stand  706  that may include a fuel source (not shown), a light source  708 , a log set  710 , an ignition system  746 , a burner  750 , and a smoke simulator  760 . The ignition system  746  may include a thermopile  748  or other device that monitors a pilot flame and/or flames  751  generated by burner  750 . The smoke simulator  760  may include a water supply  762  and first and second transducers for generating a vapor stream  768  and simulate embers (not shown). The light source  708  may help alter a color of the vapor stream  768  and flame  758 .  
      The display  700  may be a portable device that can be positioned at any location inside or outside of a living structure. The display  700  may include a self-generating source of fuel such as an electrolyzer that is powered by power cord  707 . Alternatively, the electrolyzer can be powered from the wind, solar energy, a generator, battery power, or any combination of these power sources. For example, solar energy can be stored onto batteries for use as needed. Cord  707  may provide power for the ignition system  746 , light source  708 , and smoke simulator  760 .  
      The display  700  may include a protective viewing panel (not shown) that extends at least partially around the burner  750 , for example, around a periphery of the platform  714 , to prevent users from accidentally touching the heated burner  750  or other objects heated by the flame  751 . Other embodiments may include one or more wall structures that surround the burner to provide, for example, a background such as a brick wall, while the display  700  is open vertically above the burner. Other embodiments may also include a covering oriented vertically above the burner with no surrounding wall structures for the purpose of, or example, protecting the burner from rain when using the display  700  in an outdoor setting while maximizing viewing of the combusting hydrogen from all sides.  
      The burners and ignition/pilot systems described above may be configured to combust a mixture of hydrogen and alternative fuels. For example, hydrogen fuel may be mixed with liquid propane or natural gas in a fuel mixing chamber at the fuel source or at any other location prior to combustion at the fuel aperture on the surface of the burner. In other embodiments, the pilot light of the system may burn hydrogen while the main burner burns an alternative fuel, or visa versa. In still further embodiments, the burner may be configured with separate apertures at the combustion surface for different fuels. Burning a mixture of hydrogen and an alternative fuel may provide advantages of improved emissions and higher efficiency as compared to burning the alternative fuel alone.  
      The burners described herein may include any desired materials that would be appropriate for use in this high temperature application. For example, the burner may be a metal member having certain features that are formed using stamping or other forming techniques, while other embodiments may include molded or caste burners. Likewise, the flame enhancement members may be formed using similar methods and may be formed separately or integrally with the burner.  
      The burners, fireplaces, and systems disclosed herein may be operable using some basic steps of operation illustrated in the exemplary process diagram of  FIG. 19 . A control signal may be generated  800  using, for example, a remote control device or wire wall-mounted device that activates a fuel source  805  to deliver fuel  810  to a valve that is in fluid communication with a burner. The fuel source may be any source of fuel as described in the above examples such as, for example, an electrolyzer, storage tank, or metal hydride device. The ignition system is then activated  815  and a determination is made as to whether a flame is detected. If a flame is detected  820 , the valve is activated to deliver fuel to the main burner for combustion  825 . If a flame is not detected  830 , the valve is activated to stop the flow of fuel  835 . The ignition system at least periodically monitors the presence of a flame to determine if delivery of fuel is still appropriate.  
      The present invention should not be considered limited to the particular examples or materials described above, but rather should be understood to cover all aspects of the invention as fairly set out in the attached claims. Various modifications, equivalent processes, as well as numerous structures to which the present invention may be applicable will be readily apparent to those of skill in the art to which the present invention is directed upon review of the instant specification.