In ventilation technology , a distinction is made between recuperative and regenerative processes for heat recovery , with the latter also transferring part of the moisture contained in the exhaust air .
Recuperators are regularly used as air preheaters (commonly called “Luvo” in power plant technology) in power plants and sometimes in combustion systems. There they serve as heat exchangers (heat exchangers) to transfer part of the heat from the exhaust gases to the fresh air. The fresh air heated in this way means that less fuel is used to achieve or maintain the desired operating temperature in the boiler .
Recuperative brakes have been used in vehicle construction since at least the 1900s, for example on rack railways such as the Rittner Bahn or the Swiss electric locomotive Krokodil . With regenerative brakes, the energy is fed back either into a power grid, as in rail vehicles and trolleybuses , or into an energy storage device in the vehicle, for example in electric cars . In hybrid cars, the regenerative brake feeds electrical energy back into the accumulator, a storage capacitor ( supercapacitor ) or flywheel storage , which originally comes from both the mechanical energy of the combustion engine ( chemical energy of the fuel) and that of the electric motor ( electric motor brake ).
Eddy current brakes are sometimes used in public service buses in order to heat up the electric heaters in cold weather using braking energy. As a result, the energy required for this is only partially generated by the generator. Big savings are possible, especially in city traffic. On warm days, external resistors are heated, which are cooled by the airstream or by fans. The contact-free eddy current brake prevents fine dust emissions from brake lining wear. A loss of braking force (so-called fading) due to increased temperature of the braking systems is also prevented, which means that emergency braking distances are not extended on long downhill journeys.
In modern vehicles with reduced fuel consumption, the voltage of the generator is increased in braking or overrun mode and thus the charging process is accelerated in order to reduce it in normal operation or to be able to switch off the generator completely and thus relieve the engine. In other techniques, a second battery is installed and z. B. for the additional need for the start-stop function during braking.
- Andreas Hartmann: Energy and heat management with thermal recuperation for passenger cars . Logos Verlag GmbH, Berlin 2014, ISBN 978-3-8325-3737-1 .
- Torsten Herzog: Strategies and potentials for reducing consumption in traffic jams . Institute for Transport, Kassel, ISBN 978-3-86219-160-4 .
- Konrad Reif, Karl E. Noreikat, Kai Borgeest (eds.): Motor vehicle hybrid drives: Fundamentals, components, systems, applications , Springer Vieweg, Wiesbaden 2012, ISBN 978-3-8348-0722-9 :
- Chapter 184.108.40.206. Recuperative braking , pp. 17–21
- Chapter 220.127.116.11. Recuperation , pp. 308-309
- Karl Ernst Georges : Comprehensive Latin-German concise dictionary . 8th, improved and increased edition. Hahnsche Buchhandlung, Hannover 1918 ( zeno.org [accessed October 8, 2018]).
- A. Loschge: Steam boilers: Training and manual for technical colleges and higher engineering schools as well as for engineers and technicians . 8th edition. Springer-Verlag, 2013, ISBN 978-3-642-91916-9 .
- Energy recovery from waste heat, Physikalisch-Technische Bundesanstalt (accessed on April 20, 2018)