Stratified storage tank

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Stratified storage tank

A stratified storage or layers storage or Thermosiphonspeicher ( engl. Stratified charge storage ) is a hot water tank , typically for a solar thermal energy . The warmest storage layer is right at the top of the storage cylinder and below there are colder storage layers through a natural layering. The water is brought into different storage heights, depending on the available feed temperature and the current temperature stratification. The feed takes place via a vertical line, the so-called storage lance, via horizontally exiting inflow pipes at different heights, in each case in the storage layer of the same temperature as the fed water. This is achieved through automatic valves by feeding the temperature layer of the respective temperature or water density. The advantage is that there is no mixing of the storage tank temperature. Turbulence of the water should therefore be avoided if possible in a stratified storage tank, because this would whirl up the storage layers. This is reduced by measures such as limiting the flow rate and using baffle plates at the inlets.

Additional heating is therefore only necessary later, as warm water can be drawn from above for a longer time, in contrast to mixed storage tanks. In addition, after a very short period of loading with hot water, it can be removed again at almost the same temperature, since the entire storage tank does not have to be heated up with it. This optimizes the energy efficiency .

Stratified charge storage systems are currently more expensive to purchase than combination storage systems , but the storage volume, on the other hand, can be somewhat smaller, and they are considered more modern due to better energy use.

In addition to storage systems for, for example, single-family houses with a storage capacity of between a few hundred and over a thousand liters, they are also available in a significantly larger form, for example as solar thermal long-term storage systems with a storage volume of several thousand liters.

Areas of application

literature

  • R. Stieglitz, V. Heinzel: Thermal solar energy: Fundamentals, technology, applications , Springer-Vieweg, Berlin / Heidelberg 2012, ISBN 978-3-642-29474-7 :
    • Chapter energy storage. from p. 595 ff
    • Chapter 8.6.3 Temperature stratification within the storage tank , pp. 629–634
  • Siegfried Blickle et al .: Expertise in installation and heating technology , Europa-Lehrmittel, 5th edition from 2014, ISBN 978-3-8085-1527-3 , pp. 562-563
  • Ursula Eicker : Solar technologies for buildings , 2nd edition from 2012, Vieweg-Teubner, Wiesbaden, ISBN 978-3-8348-1281-0 , from chapter 3.1.2, p. 64 ff
  • Significance of the temperature stratification in solar storage tanks. In: B. Weyres-Borchert, B.-R. Kasper: Solar heat: technology, planning, house systems , ISBN 978-3-8167-9149-2 , pp. 44–45
  • MK Sharp, RI Loehrke: Stratified Thermal Storage in Residential Solar Energy Applications In: Journal of Energy , Vol. 3, No. 2 (1979), pp. 106-113. (English)
  • Leukefeld , Baer, ​​Hüttmann: Modern heating with solar thermal energy: Security in the changing world of energy technology , Publisher: Solare Zukunft, 2nd edition from 2015, ISBN 978-3-933634-44-3 , pp. 59–61

Web links

Individual evidence

  1. ↑ Siegfried Blickle et al .: Expertise in installation and heating technology , Europa-Lehrmittel, 5th edition from 2014, ISBN 978-3-8085-1527-3 , p. 565
  2. ↑ energie-experten.org: Stratified charge storage , accessed on March 26, 2017
  3. ↑ Stratified storage tank: detailed description , see subsection: For whom is a stratified storage tank worthwhile