Which do you think is easier for a soldier to put up: a canvas tent or a 20-foot-tall structure that resembles a bomb shelter?

Amazingly, it's the clunky, rigid box pictured below.

The Army engineers who designed this structure would probably take issue with such a crude description. The deceptively elegant unit, made to house ten soldiers on the battlefield, can be set up by four people in just fifteen minutes. It's so lightweight that one person can handle a 20-foot wall, according to the Army.

These structures don't just save time. With a thermal resistance three times better than the conventional canvas tents used by the military today, they are far more energy-efficient, as well.

And don't let the drab bomb-shelter look fool you. These structures are also tricked out with enough clean technologies to make a Solar Decathlon contestant weep: LED lights, waterless urinals, rainwater collection units,solarsystems, and backup storage. The team responsible for testing these living spaces says they are between 35 percent and 75 percent more efficient than the tents currently in use.

Considering that the military spends $20 billion a year on air conditioning alone, deploying these units on a wide scale would be far less expensive to operate.

The Army set up the test encampment pictured above in Natick, Massachusetts. It has plans to build a new encampment at Fort Devons and another in Australia to support joint military forces in a tougher, hotter environment. If the units continue to perform well, they could soon be put to use in Afghanistan.

This is yet another interesting example of the military's aggressive focus on deploying energy efficiency and cleantech in order to save time, save money and save lives.