What is a thermal storage unit (ESU) in a cryocooler?

A device able to store thermal energy without large temperature drift (Energy Storage Unit – ESU) is coupled to the cryocooler cold finger through a thermal switch: during the first phase (pre-cooling phase), the ESU is cooled down with the thermal switch in its high conductance state (ON state).

What is an energy storage unit?

An energy storage unit is a device able to store thermal energy with a limited temperature drift. After precooling such unit with a cryocooler it can be used as a temporary cold source if the cryocooler is stopped or as a thermal buffer to attenuate temperature fluctuations due to heat bursts.

How much liquid nitrogen is enough to store 2600 J?

The variation of liquid volume during this experiment is plotted in the same figure (dashed line, right scale): actually, 13 cm 3 of liquid nitrogen would be enough to store 2600 J between 65 and 83.5 K using an expansion volume of 6 L.

What is a liquid energy storage unit?

Principle A liquid energy storage unit takes advantage on the Liquid–Gas transformation to store energy. One advantage over the triple point cell is the significantly higher latent heat associated to the L–G transition compared to the S–L one ( Table 2 ), allowing a more compact low temperature cell.

What is the temperature range of a spherical energy storage unit?

In the 60–100 K temperature range, despite the differences in the Debye temperatures, this feature globally remains: in Table 1, the mass, volume and thermal diffusion time of a spherical energy storage unit able to store 1800 J (e.g. 1 W during 30 min.) between 75 K and 80 K are computed for various materials.

How much energy does a system store?

Between 65 K and 83.5 K, the whole system stored an useful energy of 3720 J (solid line in Fig. 5, calculated as Q applied t) and the parasitical power (circles) is accounted for an additional total energy of ≈50 J to be stored by the system.