Maria Telkes – the Sun Queen

By Jaime Seltzer

Maria Telkes was an inventor and scientist, born in 1900 in Budapest, Hungary. The idea of solar power as an inextinguishable source of energy fascinated her even in high school, and she knew from an early age that she wanted to study the power of the sun. She earned her B.A. and Ph.D. in Physical Chemistry in Budapest when she was twenty and twenty-four, respectively, and settled down to teach at the university there.

In 1925 she emigrated from Hungary to the United States, initially to visit a relative; but while she was staying there, she was invited to work as a biophysicist at the Cleveland Clinic in Ohio. Maria agreed, and worked for several years with the founder, George Crile, on projects that likely seemed fantastical at the time. She and Crile pioneered a photoelectric method to measure brain waves, and co-authored a book on the subject. Telkes also worked on “life transformative energy”, seeking to answer questions of how a healthy cell becomes cancerous, how a cell dies and what causes cell death, and to identify the source of life’s energy: questions at the heart of the biological sciences.

Shortly after she presented her desalination device to the Navy, she produced the plans for the world’s first entirely solar-powered house.

In 1939, Telkes was hired by MIT for their Solar Energy Conversion Project. While working at MIT, Telkes developed a desalination device for the Navy. In her design, the sun heated seawater, allowing the pure water to evaporate and leaving the salt behind. When the water evaporated, it ran down into a collection tube for drinking. The device was small enough to be used on a lifeboat, but the same design was also used to create a source of drinking water for the entire Virgin Islands. Her design saved the lives of many men whose ships went down during World War II.

Maria wasn’t one to rest on her laurels, however. Shortly after she presented her desalination device to the Navy, she produced the plans for the world’s first entirely solar-powered house. She enlisted the aid of architect Eleanor Raymond, and the funding came from the wealthy sculptor, Amelia Peabody.

The house was nothing less than a work of genius made possible by Maria’s – well, genius – but also by her background in a variety of fields. When the house was designed and built in 1948, Maria had expert knowledge of chemistry, biology, physics, and metallurgy, with specific emphasis on the transfer of energy in living and non-living systems. She might well have been the only person alive at the time who could have made the logical leaps inherent in her design.

The house had several layers of insulation, as all houses do; but in Maria’s design, the first layer was glass, and the second was made of metal. The sun heated the glass, and super-hot air became trapped between the glass and the metal. The metal absorbed that heat and released it into a final chamber between the walls, and fans spread that super-warmed air around, warming the very walls of the house.

This in and of itself would be pretty incredible, and probably heat a house relatively well on most sunny days. However, Maria had the idea to include some sodium sulfate in the walls.

Sodium sulfate has unique properties that made it incredibly useful for the purpose of heating a house. First of all, it is very unreactive. In other words, it does not tend to, say, combine with the oxygen in the air and turn into some other chemical! Instead, it stays plain old sodium sulfate.

What it does do is take on water and dry out again. This process of crystallization and de-crystallization – you guessed it – stores and releases heat. On cold days, the sodium sulfate would absorb heat from the sun and transfer heat into the house through the process of crystallization. When it was hot in the house, the sodium sulfate would absorb the heat from the house and de-crystallize, leaving the house nice and cool. Because it underwent crystallization and decrystallization over a narrow temperature range, more energy could be gained or lost per gram than with many other chemicals, meaning that the process was effective without using tons and tons of the stuff.

Finally, as chemicals go, sodium sulfate was super-cheap. This meant that the sodium sulfate could be throughout the house without breaking the bank. Maria’s plan and Eleanor’s design meant that this system could heat the five-bedroom house, even through a cold Massachusetts winter.

But Telkes still wasn’t through with world-changing inventions and ideas. Next, she turned to solar ovens for cooking food. Her designs had numerous advantages: for one thing, the solar oven cooked food more slowly, which meant that more nutrients stayed in the food. Her ovens were cheap enough for people in third-world countries to be able to locate the necessary materials. Using a solar oven meant that plant material that could be used for building or weaving no longer had to be used to feed a fire to cook with, and food did not need to be stirred and monitored, freeing up time for other tasks. Telkes received a $45,000 grant from the Ford Foundation in order to help develop her designs, quite a hefty sum in 1954.

In 1958, Maria returned to industry, developing solar dryers, water heaters, and devices that would be able to be used in space. She even designed one of the labs for her employer! In the 1960s, Maria helped create devices that would work in space that were used on the Apollo and Polaris, containers that would hold measuring devices, keeping them safe in space, for example.

Maria being in the right place, working with the right people at the right time was more than just coincidence. She had the ability to work with a wide variety of personalities, and had no compunctions about moving around a lot in order to be able to work on the projects that most intrigued her. Knowing that she wanted to study solar power from such a young age allowed her to obtain the background she needed, even though it was in many different fields of study.

Maria Telkes continued to work, lecture, and teach others well into her nineties. She passed away during a return trip to her native Hungary – her first sight of home in over seventy years.

Kubiszewski, I. (2006). Telkes, Maria. In The Encyclopedia of the Earth. Retrieved from
Oakes, E. H. (2007). Maria Telkes. In Encyclopedia of World Scientists (Revised ed., p. 714). New York, NY: Facts on File, Inc.
Telkes, Maria. (2005). In Encyclopedia of World Biography. Retrieved September 25, 2015 from

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