Solid Fuel Solid-Fuel Heating Appliances

1 IntroductionHeating with woodWood stovesFireplacesFireplace insertsMasonry heaterCentral wood-fired Heating systemsWood-fired boilersWood-burning furnacesWoodWood-burning appliance installationPellet-burning appliancesPellets and similar fuelsPellet appliance installationCorn-burning appliancesCoal-burning appliancesStraw burnersEnvironmental benefitsResource organizationsEngineering ExtensionJune 2003 Table of ContentsSolid FuelHeating Appliances Solid -FuelHeating Appliances 2 Heating with Solid fuels was the norm for thou-sands of years. Wood and coal were common fuelsbut in areas devoid of these resources, peat, agricul-tural residue, and dried animal dung were also advent of modern, safe, and automatic gas- orliquid-fueled Heating Appliances has replaced mostsolid- fuel Heating Appliances .

2 Tending the fire in asolid- fuel Heating appliance requires at a minimum,addingfuel andremovingash have grown accustomed to simply adjusting thethermostat if we are uncomfortable In spite of the inconvenience, Heating with woodor other Solid fuels has continued. Burning wood forfuel can be a cost-effective way to heat. Hardwood at$100 per cord, burned in a modern wood stove, isroughly equivalent to natural gas at $ per MCFor propane at $.30 per gallon. During times ofincreasing fuels prices, use of wood undergoes arenaissance. In1960, theEnergyInformationAdministrationestima tedKansans burned157,000 cords ofwood. Thatamount steadilydeclined until1974, the timeof the initialenergy crisis.

3 Bythe 1980s, woodconsumptionwas over half amillion cords inKansas andstayed at thatlevel until nearly1990. Wood useagain declinedand in 1999,Introductionabout 200,000 cords were consumed. While cordwood use has declined, other Solid fuels are gainingpopularity. Corn, pellets made from wood, and coaluse as Heating fuels has grown in recent years. The decision to heat with wood is not just an eco-nomic one. Cutting wood for heat provides the indi-vidual a sense of control and self reliance. And whenthe power goes out, many who heat with a sold fuelwill continue to have warm houses. Most Solid fuels, with the exception of coal, areconsidered renewable fuels.

4 Using them for heatrather than fossil fuels reduces depletion of finiteresources. Using renewable fuels also reduces releaseof carbon dioxide, which has been linked to globalwarming. However, using inefficient Solid - fuel heat-ing equipment releases large quantities of smoke andunburned particles into the air and reduces air quali-ty. In some areas of the country, air-quality problemslimit the resale of inefficient and polluting stoves,prohibit use of certain types of wood-burning appli-ances during times of poor air quality, or otherwiserestrict use of certain Appliances . Check with localofficials before purchasing or installing any Solid -fueldevice.

5 Old wood burns brightest. John WebsterWood burns in several phases. First, the wood must reachignition temperature. Usuallysome moisture will be drivenoff at this stage. Wood begins to break downchemically at about compounds arereleased and burn at 1, high temperature must bemaintained or some of thevolatile gasses will not burn. Finally, the remaining charcoalburns slowly at temperaturesexceeding 1,100oF. Emissions are higher fromsmoldering fires, when flamesimpinge on cool surfaces, andwhen unseasoned high-mois-ture wood is is the most popular of the Solid fuels forhome Heating . Wood is burned in conventional fire-places, improved fireplaces including inserts, woodstoves, masonry heaters, and central furnaces and boil-ers.

6 The relative efficiency and emission characteristicsof each of these Appliances are detailed in Table 1,Efficiency and particulate emissioni. These values rep-resent average values; actual ratings will with wood 3 ApplianceEfficiencyStovesConventional (Pre EPA rule) EPA EPA open convection, natural tubes, C-shaped with glass convection with blower and glass insert , EPA insert , EPA stove insert75 NegligibleGas-fired fireplace50 NegligibleCatalytic fireplace-like wood stoves, EPA certified Boilers and Furnaces50 UncertainTable 1. Efficiency and particulate (Pounds per MBtuHeat Delivered)Wood stoves are some of the most popular andefficient Solid - fuel home- Heating Appliances .

7 Earlierwood stove technology increased the Heating efficien-cy and burn-time of a wood charge by throttling theamount of combustion air allowed to the fire. Whilethis extended the time between charges of wood andincreased efficiency over open fireplaces, the slow-smoldering burning process emitted large amounts ofcarbon monoxide and particulate materials. Someareas of the country suffered significantly from thepollution from early air-tight wood stoves. Improvements in stove technology during the1980s have increased stove performance to around70 percent, with emissions three to five times lowerthan early air-tight stoves.

8 New wood stoves mustmeet federal emission standards before they can besold. This helps assure they are both efficient andnon-polluting. Both non-catalytic and catalytic woodstoves are available. Non-catalytic stoves are most common. They haveair controls and baffles to route combustible gassesreleased from the wood into high-temperature areasto assure complete combustion, high efficiency, andlow emissions. Primary combustion air is preheatedto promote complete burning. Metal baffles keepcombustion gasses in the primary combustion zoneas long as possible. Combustion of the charcoal por-tion of the fuel occurs in the primary combustionzone.

9 Unburned combustible gases then enter a high-temperature secondary combustion zone where pre-heated secondary air is introduced to finish the com-bustion process. Non-catalytic stoves often have small fire boxeswhich are usually insulated or have fire brick tomaintain high temperatures, and air inlets that areadjustable but cannot close completely. Catalytic stoves use a specially treated ceramiccombustor, similar to the catalytic converter on yourcar, to assure complete combustion. Fires are builtwith the combustion gasses initially bypassing thecatalyst. When temperatures reach 350-600oF, thegasses are routed through the catalyst.

10 Preheatedcombustion air is usually admitted near the catalystto assure complete combustion. Proper operation isWood stoves 4critical to assure low emissions and long catalyst untreated wood should be burned and temper-atures above 1,600oF must be avoided to preventharming the catalyst. Catalytic stoves cost more andmany require maintenance of the catalytic can be equipped with glass fronts to allowfor viewing the fire. Early glass-door systems did notstay clean. Newer designs employ an air curtainacross the glass surface to keep the glass clean andsoot per Cord$80$100$120$140 Price per Delivered Million BtuSpeciesfor Typical EPA-Certified Wood StoveCottonwood$ $ $ $ , American$ $ $ $ $ $ $ $ $ $ $ $ , Silver$ $ $ $ , Red$ $ $ $ Orange$ $ $ $ 2.