Drying wood chips on a small scale is easy. There are many different methods and tools that can be used to dry the wood, both at a natural and accelerated pace. Each of these methods has different advantages, disadvantages and costs. Consider your circumstances and drying needs before choosing a tool for drying wood chips.
Air drying is the easiest and cheapest way to dry wood for wood chips. In this method of drying, logs of wood are split into small chunks so that the interior of the wood is exposed to the air. It takes one to two years for the wood to dry thoroughly. The wood must be placed in a mostly dry area where snow will not collect. An open carport or shed works well. The cost for this method of drying wood chips is no more than the cost of the wood, land and shelter.
A drying shed is a popular wood chip drying method for areas where the air is moist and long winters are common, such as in Scotland. These sheds blow dry air around the wood with the use of fans, which accelerates the drying process. Usually the drying sheds are not used to dry the wood completely, but rather to eliminate the first 20 per cent of moisture from the wood. The cost of a drying shed is about one-third of kiln drying, which adds up to a high cost savings over several years. Drying sheds produce wood ready for kilning in two to four months. A drying shed costs anywhere from £1.90 to £4 per 305 m (1,000 feet) of board per eight days.
Accelerated air drying
An accelerated air drying system for wood chips encompasses a warehouse-size drying shed that pipes hot air over the wood. The temperature of the air is usually under 54.4 degrees C (130 degrees F) and averages around 26.6 to 32.2 degrees C (80 to 90 degrees F). The cost of the accelerated air drying systems is higher than that of drying sheds and air drying. The time it takes for wood to dry is longer as well. This makes accelerated air drying systems much less favoured by wood chip and other hardwood driers. Wood dried in an accelerated air drying warehouse is dry within four to six months and costs run anywhere from £4.20 to £9.00 per 305 m (1,000 feet) of wood per eight days of drying time.
Most wood is kiln dried after being air or warehouse dried. A kiln is a climate-controlled chamber that circulates heated air between 37.7 and 54.4 degrees C (100 and 130 degrees F) rapidly over the wood for a few weeks. Once the wood has reached a certain dryness (around 75 per cent), the temperature is increased to 65.5 to 93.3 degrees C (150 to 200 degrees F) until the wood has reached about 90 per cent dryness. There are two main types of traditional kilns -- package and track. Package kilns are cheaper because they use older technologies. However, they also cannot handle as much wood or green wood. Track kilns are more expensive to operate but they dry wood faster and can handle greener wood. Kiln operation costs run anywhere from £6.00 to £12.00 per 305 m (1,000 feet) of wood per eight days of drying time.