Energy Storage: Liquid Nitrogen

by Keith Heyde

Energy storage: the ability to transport energy over distances and in a safe and easily used fashion. Chemically, physically, or by other means, it is a challenge of both efficiency and capacity. In our energy storage series we take a look at some of the real and proposed technologies for storing and moving energy.

This week: Liquid Nitrogen (LN2)

Whether it was in a middle school science class or at the dermatologists, most people are familiar (at least to a degree) with liquid nitrogen. That canister that continuously smokes off in the corner is a familiar and intimidating image evoking thoughts of mad scientists and not energy storage.

However, within the cold confines of liquefied nitrogen, there are many properties useful and promising for advancement in the world of energy storage.

If you look back to the article on heat exchangers and air handler units (http://www.energygridiq.com/inside-the-air-handler/) you will see that a heat exchange works by ‘sucking’ the hot energy out of the air and moving it to another location. In a system that used liquid nitrogen as an energy storage vehicle, the liquid nitrogen would suck heat out of the air and the result would be a pressurized gas that could drive a piston to power and engine.

Of course, the liquid nitrogen would have to be generated using stirling engines (as it is today most of the time).  However, the advantage is that stirling engines can generate liquid nitrogen directly from mechanical sources. This means that wind turbines, rather than waste efficiency on generating electricity (which is not well monitored and has variable capacity) could generate liquid nitrogen that may be selectively released.

At its simplest form, it means that our wind and hydro facilities can be used giant liquid nitrogen manufacturing plants rather than electricity producers.

Liquid nitrogen energy storage is still in its infancy and many issues such as lubrication exist with successfully designing a LN2 engine. However, the technology does have promise due to the physical simplicity of the system, advances in thermal insulators, and abundance of N2 in the atmosphere.

For more on liquid nitrogen take a look at some additional articles:

A fun look at a research project turned vehicle!

http://www.mtse.unt.edu/CooLN2Car.html

An analysis of the energy benefits of using LN2 systems.

http://large.stanford.edu/publications/coal/references/docs/sae98.pdf

A breakdown on conventional LN2 storage methods.

http://liquidnitrogentank.com/

 

And for more news and info on energy storage, or just energy thoughts in general check back to www.energygridiq.com.