how do pellet stoves work?
Pellet stoves are a lot similar to wood stoves when you look at it from the outside, but inside they are sophisticated combustion appliances. The device holding the pellets is called the “hopper,” while the device that transfers it to the next chamber is an “auger.” To use it, you just need to load pellets into the hopper. The size of the hopper varies for each stove, and obviously, the bigger the hopper the more pellets you can load. There are two types of pellet stove: How pellet stove worksTop Feed – where the auger serves the pellets from the top. This type lessens the risk that the fire will burn back to the hopper. Although there is a chance that the ash gets caught up in its firebox grate, build up and cause the fire to die.Bottom Feed – where the auger serves the pellets horizontally and its ash moves to the sides where there is an ash pan to make cleaning and maintenance easy and safe. Some stoves are automatic while some will require you to manually light it.
Pellet appliances are now a generally accepted heating source. Over 1.2 million tons of pellet fuel and 120,000 pellet appliances were sold in North America in 2006. Pellet systems burn fuel made from dried ground wood or other biomass waste compressed into small cylinders. The pressure and heat created during their production binds the pellets together without using additives. Pellet burners include a hopper that holds 40-70 lbs. of fuel and a ‘corkscrew’ auger to automatically feed the pellets into the combustion chamber. Pellets burn cleanly since they are fed to the chamber at a controlled rate and are matched with the right amount of combustion air. If they are properly adjusted, pellet-burning stoves can operate at a lower emission level than natural firewood appliances. Buying a pellet stove is not for everyone, but for people who don’t mind a little extra work for big results, it can dramatically reduce your home heating costs.
Pellet stoves are hearth products that make use of electrically-controlled blowers, combustion systems, and heat exchangers. In layman’s terms, this means that pellet stoves burn fuel slowly, release as much energy as they can from the pellets, and draw in cool air and release it out as hot air. To use a pellet stove, pour the pellets into a holding area, which is called the hopper. If the hopper is very big, enough fuel that can burn for several days can be accommodated. Most pellet stoves can produce heat for one to two days on just one loading of pellets. Within the stove is an auger, which is an automated feeding system. It controls the pace at which the pellets are fed to the fire. For instance, if the rate is one pound an hour, a slow fire is generated, thus heating the room for a long time. If the rate is higher, say, four to five pounds per hour, the fire will be bigger so the room will be warmer. Some pellet stoves are self-lit, while some are needed to be manually lit.
Pellet stoves consist of 1) a hopper where the pellets (about an inch long) are loaded 2) an auger that moves pellets from the hopper to the 3) combustion chamber burner and 4) a fan to either force air into or pull it through the chamber to super heat the combustion and 5) a fan driven heat exchanger that pulls cold air from the room and returns warm air back Although the fans require some electricity to run, the net payback in terms of heat energy and efficiency is huge. Also the more complete combustion of the compressed dry pellets leaves very little ash to dispose of. The first efficiency is in the pellet fuel itself. Pellets can be made from waste products from sawmills and other wood processing facilities, biomass sources such as grasses, corn, and nut shells. The compressed pellets store easily. They usually come in 40 lb bags and take less space to store than wood of the same energy output.
Instinctively, there’s nothing as soothing as a log fire. But after 7 winters hauling firewood, for me, the romance is long gone. Pellets are a lot less hassle. The 40 lb. bags are manageable and occupy 1/3 the space of stacked wood. Pellets are also way cheaper than propane or electric heating. Still, you need a pickup to haul 2-4 pallets for the winter. A local dealer would charge $50 to deliver a pallet to my home 10 miles away. Unlike wood stoves, pellet stoves also have a lot of moving parts that can go bad, especially with poor quality pellets that don’t burn completely, leaving clinkers that gum up the augur, combustion chamber, and exhaust system. Though wood products generally contain less sulphur than coal or fuel oil, propane and natural gas actually burn cleaner than pellets because they emit little or no smoke. Pellet stoves do tend to emit far less smoke overall than hardwood, but smaller (<0.3 micron) particles. The tiniest ones penetrate most deeply into our lungs.
