The Mechanics of Wood Pellet Stoves
Wood pellet stoves operate with electricity. The pellets are loaded into the hopper, which is located either on the top or the bottom of the unit. The auger, which is like a long screw, is a motorized device that delivers the pellets from the hopper into the burn pot. The auger's speed determines the temperature of the stove.
The burn pot, which is housed in the combustion chamber, is then ignited. Pellets are heavily compressed, so they're dense and low in moisture, creating a hotter flame. The burn pot serves as the carburetor for the stove, mixing the air and fuel to create combustion, which simply put, is the process of burning. The ashes from the burnt pellets are captured in an ash pot, which needs to be cleaned periodically.
Unlike a standard fireplace, a pellet stove heats a room through convection. As you probably know, hot air rises. This is because as a gas rises in temperature, it becomes lighter and less dense, causing it to rise above the heavier cool air. Convection is the transmission of heat that occurs from this forced combination of cool and hot air currents. So, the convection blower pulls cool air in from the room, passing over the fire in the burn pot and making the flame hotter, which enables the pellets to burn evenly and efficiently.
This heated air then moves across a heat exchanger, which is designed to transfer clean air into your home through the room blower. The heat exchanger acts as a furnace when it's used in combustion, and it's located in the combustion chamber to prevent the outside of the stove from becoming hot.
The exhaust blower pushes the gases out of a narrow pipe in the back of the stove. This pipe can be vented into an existing chimney or connected to the outside through a small hole. It's important to note that even though a chimney isn't required, the exhaust blower is most effective when the pipe is installed at a vertical angle.
The stove is operated by a thermostat, which controls the number of pellets that the auger feeds into the combustion chamber. More pellets equals more heat. For example, pellets delivered at one pound (0.453 kilograms) per hour produces a gentle flame that will last a long time, but at five pounds (2.267 kilograms) per hour, your fire will blaze [source: hometips.com].
Next, we'll discuss the different types of pellet stoves.