Abstract
The development of the first practical electric snow melting installation in Hokkaido has succeeded sufficiently in the Sapporo city in winter 1963-1964. After this success many road heating systems were installed in every place. About 1700 m2 (480 kw) electrically heated roads in Hokkaido at the end of 1964 will have increased to 6000 m2 (1500 kw) by 1965.
Summary of generally used electric road heating installation is :
1) Heating cable is a 7/0. 5 m/m Ni-Cu alloy wire, butyl rubber insulated and P.V.C. sheathed.
2) Cable is embedded 3-5 cm depth with 5-7 cm spacing.
3) Watt-density is about 250 watt per square meter.
4) Energy supply is 500-600 hour per season.
The paper gives details of above experience in Sapporo, analysis and theory of road heating system, heating cables and some inotallations in the foreign country.
It is also suggested that there is scope for futher research in this field, including the problems of watt-density damage of road surface, autmatic control and energy supply.
