Low-Cost and High-Maintainability Walkway Snow-Free System Employing WarmAir as Heat Medium.

In 2000, Japanese government introduced "the law of barrier-free transportation", which covers major points of transportation, such as bus terminals, train stations and so on. Target of the law is not vehicles but pedestrians, especially for old people and/or disabled people. One of the motivations of the law was acceleration of social participation for disabled people, and also the rapid aging of Japan's population. In the snowy region, snow-covered or frozen footways are a severe barrier for weak persons. There are some ways to realize barrier-free condition, such as mechanical snowremoval, chemical anti-freezing and road heating system. Road heating could bring excellent snow-free condition on the walkway, but the life-cycle cost, including initial, running and maintenance cost, is exceptionally high compared with mechanical or chemical way. The cooperative project have developed a new walkway snow-free system employing air as heat medium, named ACCESS (Air-Circulation Technique for Cost Effective Snow-free System),having some advantages of low construction cost and high maintainability.The system consists of heat source, air-circulation unit and snow-meltingpaver. To adopt a newly developed paver having ventilation duct, make construction process simple and save construction time and cost, and make recovery process much easier when there are lifelines under snow-melting walkway. Field experiments with two prototypes were carried out in 2004 winter. One system had used exhaust gas of a gas-turbine co-generation system asboth heat source and heat medium, whereas the other had adopted a combination of warm-water and a warm-air circulation. A prototype of the interlocking paver having ventilation duct (IPV) was examined for its snow-meltingperformance. Snow-melting performance of these experimental facilities was 40 - 90 W/m2. Theory and some laboratory experiments yield the design diagram specialized for the air-medium snow-melting system. The air-flow system utilizing the exhaust gas of gas-turbine co-generation system brought 6.1% energy saving. Finally, it was shown that the cost of the ACCESS is likely to be less than half of the other snow-melting system. For the covering abstract see ITRD E143097.