Daimler-benz Ag

Friedrich Baehrle

Helmut Wulf

Helmut Kreeb

A heat pipe of aluminum is provided on the inside on all sides thereof with a completely closed fluid-tight coating of a water-resistant nickel in order to make the same resistant against water as heat carrier medium or to make the same vacuum-tight for long periods of time. Also, a coating of hard solder material is possible. The coating thickness is no less than 10 .mu.m and no more than 15 .mu.m. Individual parts of the heat pipe, prior to the soldering, are coated with the nickel material, each by itself, completely up to the joint areas. A process of making the heat pipe is also provided.

Heat pipe of aluminum, steel or gray cast iron

A road heating installation which is supplied by heat stored in the ground and which includes heat pipes placed heat-conductingly with the road surface, is provided with sensors for detecting the climate factors relevant for the road condition and is equipped with a control apparatus that controls the heating installation as a function of the climate. In order to remove the heat energy stored in the ground only in case of need and to avoid the unnecessary exhaustion thereof, the invention provides that the heat transfer capacity of the heat pipe is controllable by a reversible blocking of the condensation zones of the heat pipes and the blocking is brought about in case of a dry-cold by the supply of an inert gas into the condensation zones of the heat pipes which is quantity-regulatable directly from the outside.

Method for heating a road by means of geothermally fed heating

A heating system for a dual-mode vehicle, such as a bus equipped with both electrical and internal combustion engine drive systems, is provided with an electrically powered heat exchanger and an auxiliary fuel heater serially connected in the engine cooling water flow line. The electric heat exchanger provides a non-polluting source of heat for the vehicle's interior within electrified portions of the drive route. The auxiliary heater supplies heat when the vehicle is standing (i.e., parked) with the engine shut off in non-electrified portions of the route. An electric water pump is also connected in series with the electric and fuel heaters. During periods of electric drive operation, the electric heater is activated when the engine cooling water temperature falls below a predetermined level even if no heat is required for the vehicle interior. The electric heater prevents the engine from cooling off and, thus, improves exhaust gas characteristics, from an environmental viewpoint, when the engine is re-started.

Growing community of inventors

Kernen-Rommelshausen, Germany

Friedrich Baehrle