When fire breaks out, keeping the building free from smoke is very important for people’s chances of survival. But smoke extraction systems do not look very spectacular. Smoke rises very quickly and usually fills the room from top to bottom. Fans and windows usually extract or channel any smoke upwards. If the smoke has sufficient time to adapt to the ambient temperature or if turbulence mixes it with the ambient air, it becomes more and more difficult to deal with when a fire has broken out. It is particularly difficult to remove smoke in buildings with unusual geometries, e. g. in an atrium, since the poisonous gas may form zones in which survival is impossible despite extraction measures being implemented. An innovative solution to such a problem is the Imtech tornado in the Daimler museum. This artificially generated tornado is 40 m high and when a fire is raging it initially channels the smoke into the centre of the building and then upwards. At the highest point of the building, the dangerous gas is then easily led to the outside.
The following film shows a water tank which is gradually filled with heat i.e. warm water. The video is played at 64-times the actual speed; in reality it takes about an hour to fill the tank. In order for the thermographic recording to become possible at all, the storage device has no thermal insulation. The slow filling means that the power of the heat generator can be kept low and steady, which also creates less turbulence. The mixing of hot and cold layers is not desirable from an energy point of view.
This film shows what effect temperature has on the strength of materials. A material under load is heated up. The material fatigue at the points which have been heated results in the workpiece breaking at a temperature of about 150°C.
The following film shows the heating of water by means of an electric heating coil; here we use the example of an electric kettle.