A modern solar-powered house on the cover of the March 1949 issue of Popular Science magazine
The solar-powered house of the future, in March 1949 Popular Science

It might seem daunting to build a solar-​powered house in Massachusetts instead of, say, Phoenix. But MIT engineers tackled the challenge with a brazen concept, which we featured on our cover in March 1949.

The Dover Sun House relied on several vats of Glauber salts, or sodium sulfate, placed throughout the living quarters. (Our illustrator depicted them as a fanciful “heat bin” in the attic.) The salts melt at 90 degrees Fahrenheit and store energy more efficiently than water. The system, devised by chemist Mária Telkes and architect Eleanor Raymond, channeled the sun’s warmth to the sodium-sulfate tanks, which meted out heat on cold or overcast days. It worked better in principle than in practice: Tenants were chilly in winter, and the tanks tended to leak. They moved out after a few years. Today, the Tesla Powerwall stores solar energy more effectively with lithium-ion batteries.

Three More Ways To Pack Power

In the 28 years that Popular Science has been honoring the year’s top innovations, several energy-storage solutions have earned Best of What’s New awards.

1991: Quick-Charge Car Battery

Developed by Nissan, the battery was touted as a big step forward in electric-car technology because it could be charged in just 15 minutes.

2007: A Rooftop Ice Block

The Ice Bear stores energy during the night by freezing a pool of water into a block of ice. During the day, the ice supplies air conditioners with cool refrigerant.

2014: Earth-Friendly Battery Stack

Aquion Energy’s modular batteries use a nontoxic, nonflammable solution to store energy from wind and solar: salt water.

This article was originally published in the December 2015 issue of* Popular Science, under the title “How To Stash Sunlight.”