The Wood Gun™ boiler by Alternate Heating Systems utilizes the most advanced technology available in wood and biomass burning devices. Capable of utilizing conventional firewood and a wide variety of biomass fuels, the Wood Gun™ is ideal for residential, commercial, and industrial applications where such fuels are available as a primary fuel source. The Wood Gun™ wood boiler comes in sizes ranging from 100,000 to 1,000,000 BTUs. Economical Energy Consultant is your source for commercial units above 250,000 BTUs.
The Wood Gun™ employs a downdraft wood gasification design which burns wood and biomass with wider ranging moisture content. These wood boilers work by drawing the wood gases off using an induction fan and then burning the gases underneath the wood at very high temperatures with abundant air, so that much more complete combustion occurs. The wood is continually heated by the burning gases beneath it so that the gases continue to emanate from the wood through a process known as pyrolosis. Since the wood gases are much more fully combusted than in a standard wood burning device, higher combustion efficiencies are obtained. If a backup fuel is required, the boiler can include automatic switchover to oil or gas backup. An optional lockout feature maintains the secondary fuel mode in the event the wood charge is expended.
Particle Fuel Delivery for Industrial/Commercial Applications
When burning chunk wood in an AHS Wood Gun™ boiler, a properly sized residential system fed high quality hardwood fuel will typically only need to be loaded two or three times a day. For commercial applications, utilizing the E500 and larger, higher duty cycles are expected and our automatic particle fuel delivery option is strongly recommended. Particle feed systems are a reliable, automated way to make use of uniformly sized wood pieces, chips, pellets, and other biomass fuels.
If you want to burn both chunk wood and wood particles in your AHS wood boiler, it only takes about fifteen minutes (after shutting the system down and allowing it to cool) to change the system from wood to particle fuel. There is no more versatile boiler available anywhere.
How Superior is the Efficiency of the Wood Gun™ Wood Boiler?
The Wood Gun™ wood boiler is a combustion system capable of burning wood and wood-based waste at a very high combustion efficiency, resulting in very low stack emissions. Stack sampling on operating units has yielded particulate levels 50% less than the best results obtained by conventional up-draft boilers. This level of performance is due to a number of unique design features not found on other wood waste combustion equipment. In fact, the Wood Gun™ is so different that conventional wood boilers cannot be modified to incorporate these features without a complete redesign.
The stack temperature is an indicator of how completely the transfer efficiency is maintained. The Alternate Heating Systems Inc. Wood Gun™ Boiler operates with one of the coolest stack temperatures of any wood boiler on the market (if not the coolest). The stack temperature of a Wood Gun™ runs at less than 300 degrees Fahrenheit (typically 260 - 280 degrees).
Because the exhaust temperature is relatively low as it leaves the chimney, it is close to the dew point and steam will sometimes appear just above the chimney. This should not be mistaken for smoke. The steam is an indicator of the low stack temperature and the very efficient combustion of the Wood Gun™. The exhaust from other boilers with higher stack temperatures (lower efficiency) will also form steam, but this only happens after the exhaust has moved higher into the atmosphere and so had time to cool to the point where condensation (steam) can occur. The colder the outside air temperature, the more likely you are to to see steam from a Wood Gun™ wood boiler.
Carbon vs. Stainless Steel in our Wood Boilers
The internal surfaces of a Wood Gun™ Wood Boiler include any surface touched by the flame, smoke, wood or exhaust. The internal surfaces may be manufactured with carbon steel or stainless steel - it's your choice. We recommend stainless steel because carbon steel will show deterioration within 10 years though the unit may continue to function for as long as 20 years. We have had stainless steel boilers in service for over 20 years, and they show no sign of deterioration. We use 1/4" thick 304 stainless steel (as opposed to 409) for unsurpassed quality.
- Automatic cycling on and off in response to heating or hot water demand.Domestic hot water coil provides abundant quantities of hot water.
- Exceptionally safe and clean burning.
- The use of dense refractory material cast into specific shapes causes complete combustion to occur at temperatures of up to 2000° F.
- When operated properly in the gasification mode, visible smoke is eliminated and creosote formation inside the chimney is prevented.
- The large cyclone separator removes most of the fly ash resulting in very low emission.
- Spontaneous re-ignition of the wood will occur after an off period of 2-8 hours. Factors such as the quality and quantity of the fuel charge as well as the size of the unit also determine how long a system can go without burning and then have spontaneous re-ignition occur.
- Automatic fuel delivery systems are available for wood waste products such as sawdust, shavings, woodchips and densified biomass. These are designed more for industrial/commercial applications rather than residential.
- Wood Gun™ readily adapts to new or existing hot air systems through the use of a heat convection coil.The design maintains all heated walls at the same temperature using a "water wall". This constant temperature eliminates stress fractures caused by differences in temperature between components of the boiler thus increasing it's life. In addition, this design produces greater efficiency because heat that is normally lost through a drywall is captured in the water wall.
We use standard parts in our boiler designs. The first wood gasification boiler was built over 30 years ago and all parts are still available as replacement parts.
How does the unique design of the Wood Gun™ swirl chamber differ from other wood gasification boilers?
The swirl chamber is where 90% of the heat exchange takes place in the Wood Gun. The Wood Gun refractory combustion area emits gases that are approximately 2000 degrees fahrenheit. This exhaust is directed into the swirl chamber, from which it will exit at a temperature of only 300 degrees or less at high fire.* This unheard of heat transfer efficiency is due to our unique design. The exhaust air spins through a large diameter drum assisted by a 3400 rpm draft inducer making a swirling action. Both the exhaust air and the ash from the wood, scrub the walls of the heat exchanger at a high rate of speed, in turn keeping it clean and efficient. This self-cleaning action prevents the troublesome routine cleaning of the heat exchanger that has plagued the wood boiler industry for years.
*The temperature varies from boiler size and duty cycle, wood/fuel quality and moisture content and flue height.
The cyclone ash seperator is where the majority of the ash is collected. Since the design of the swirl chamber utilizes the ash as a cleaning agent, we can allow the ash to exit the boiler with the exhaust air. The speed of the ash is increased using a high velocity orifice, through which it discharges into a cyclonic ash separator, spinning the heavy particles out of the exhaust stream and finally funneling them into the stainless steel ash pan allowing the exhaust to exit the cyclone top into the chimney pipe.
|Nominal BTU/H Wood||100,000||140,000||150,000||185,000||230,000|
|Oil (optional) **||80,000||130,000||160,000||160,000||230,000|
|Heating Surface||30 ft2||39 ft2||46 ft2||55 ft2||70 ft2|
|Water Capacity||60 Gal||80 Gal||80 Gal||95 Gal||140 Gal|
|Fire Box Capacity||6.5 ft3||10 ft3.||14 ft3||18 ft3||22 ft3|
|Max. Log Length||26"||30"||30"||38"||46"|
|Load Door||14" x14"||14" x14"||14" x14"||14" x14"||14" x14"|
|Domestic Coil Gal/min (Optional)||5||5||5||5||5|
|Average Output for 8-12 Hour Burn Cycle (use for sizing)||70,000||100,000||140,000||175,000||220,000|
|Nominal BTU/H Wood||500,000||1,000,000|
|Net Steam Rating (BTU/H)||376,000||752,000|
|Heating Surface||116 ft2||192 ft2|
|Water Capacity||210 Gal||435 Gal|
|Gas/Oil Chamber (water capacity)||16 Gal||50 Gal|
|Weight (w/o gas/oil - lbs)||4,500||9000|
|Induction Fan Motor||.75 HP||2.0 HP|
|Minimum Boiler Room (w/o Gas/Oil)||12'x15'||16'x16'|
|Minimum Boiler Room (with Gas/Oil)||14'x15'||16'x18'|