The New Thermal Storage Technology can absorb and release heat at the same time because loading and unloading takes place in separate pipework systems. Certain areas of the storage installation have a practicable minimum temperature for regeneration of electricity for as long as possible.
The following graphic describes an example of the course over time of such a fluctuating introduction of heat. About 40% of the time (horizontal axis) the temperature (vertical axis) is below the minimum usable temperature (“Tmin”) for reconversion. With conventional heat storage systems, a subsequent turbine would have to start and stop frequently. In addition, charging would first have to be stopped in order to enable discharging. The heat available during this period would be lost.
With the New Thermal Storage Technology, on the other hand, the fed-in thermal energy is smoothed by diverting the heat to other modules at specific time intervals (vertical dashed lines), while at the same time discharging can continue continuously.
The time axis is divided into sections a to t. Exemplary procedure for cyclical feed-in of heat:
a) Serial charging module 3 - 5
b) Serial charging module 2 - 4
c) Serial charging module 1 - 3
d) Serial charging modules 2 – 4
e) Serial charging module 3 - 5
f) Serial charging module 5 – 6
g) Serial charging modules 4 – 6
The thermal energy below the usable level (“Tmin”) is also fed in, stored and finally recovered.
Portion of stored heat for reconversion:
Small sub-units reach a maximum temperature somewhere in the system more quickly than a large mass. The New Thermal Storage is therefore ready for operation more quickly.
When discharging, the heat is first removed from the coldest module and used to preheat the other modules; very hot areas are initially spared if necessary. More stored heat is thus made available for reconversion and the withdrawal period increases.
The storage is ready for discharge early because the first modules are charged quickly.
Round steel pipes 70.0thinsp;xthinsp;6.3 mm are provided for the internal piping for loading and unloading, the distances between the pipes are 20thinsp;cm. The piping systems are twisted by 90° to each other, so that there are 48 parallel pipes along the module length for loading and 128 pipes along the module width for unloading.
In addition, there are 56 melting cores (tube dimensions as above) with aluminum filling in each module.
The gaps are filled with a bulk material, of which it can be assumed that the heat capacity is 0.8thinsp;KJthinsp;/thinsp;(kgthinsp;K).
In total, approx. 5thinsp;600thinsp;kg of steel, 2thinsp;120thinsp;kg of aluminum and 19thinsp;500thinsp;kg of sand are installed per module.
If a module is used from 350°C (minimum temperature for microturbines) to 850°C, the following amount of energy results for reconversion:
|Material (1 Module)||cp [KJ / (kg K)]||m [kg]||Qsensibel [kJ]||Qlatent [kJ]|
|Charging piping made of steel||0.75||2077||778'000||0|
|discharging piping made of steel||0.75||2'266||850'000||0|
|Melting core shells made of steel||0.75||1'271||477'000||0|
|Melting core filling made of aluminium||0.88||2'120||954'000||844'000|
Is the New Thermo Storage Technology superior to actual storage systems?
How efficient are the competing products?