Koga Shinya

An Opaque Solar Lumber Drying House Covered by a Composite Surface

Since old time, natural air drying technique had been utilized in several areas of the world before artificial drying methods for wood were developed. In Hokkaido, Japan, a research on the modified type, in place of the natural air dryer, was developed as a practical technology. For instance, the solar dryers of greenhouse-type and solar house-type were made by hand or constructed architecturally. After tested at the public institute, some of the apparatus were distributed to some areas of northern part of Hokkaido. For several decades, from just after the first energy crisis 1973 until the recent time, as an application of solar radiation in the field of forest industry, an active-type and a semi passive-type of solar wood dryers have been developed experimentally and constructed annually. For instance, a semi passive-type handmade solar lumber dryer was invented by the Hokkaido Forest Industry Product Institute, which occupied one era in a wide area as an auxiliary lumber dryer. Recently, in order to suppress the global warming, a policy to reduce emission of carbon dioxide was urgently required on the worldwide. For example, an artificial steamtype lumber drying emits a lot of carbon dioxide because it consumes a lot of fossil oil, i.e., about fifty liters per one cubic meters of wood.