Just an hour and a half outside Tashkent, a fascinating Soviet relic sits perched on a hillside near the village of Changikhisarak. One of the Soviet Wonders of the World, the физика-солнце, literally “Physics Sun” Institute of Uzbekistan, is the second biggest solar furnace in the world surpassed only by the Odeillo solar furnace in the Pyrenees of southern France. Until recently, the Uzbek furnace was heavily guarded and off limits to anyone without a permit, but lately restrictions like these are being lifted at interesting sites all over the country. Built between 1979 and 1986, the furnace is capable of producing temperatures in excess of 3,000°C by focusing one megawatt of the sun’s energy onto a one square meter target.
Within the former Soviet Union, the complex was ideally located to take advantage of the abundant sunlight and low humidity climate of eastern Uzbekistan. The mountainous terrain also provided engineers with an optimal slope for capturing the sun’s energy at just the right angle. High altitude, (1100 meters above sea level), and with full sun on average 270 days per year, the location was perfect for scientific work involving solar energy.
The idea to build the furnace was first conceived during the space race in the late 1960s and 1970s as Soviet authorities were looking for an ideal platform on which to test materials that could endure rapid changes of temperatures like those encountered during extended missions to the moon, and during atmospheric re-entry. While the Soviets never actually made it to the moon, the facility still has applications for testing materials subject to thermal shocks, and for testing ceramic insulation.
The furnace is capable of producing such extreme heat thanks to an array of 63 flat mirrors (heliostats), each the size of a two-story house, and equipped with sensors that ensure each panel follows the sun at the optimal angle to reflect the sun’s rays back onto the 55 meter (175 ft) parabolic mirrored primary collector. There are 12,090 individual mirrors that make up the combined mirrored surfaces of the entire complex. Each and every mirror is numbered and custom made, curved and optimally placed for maximum effect.
The main parabolic mirror (concentrator) focuses the light into a one square meter disk within a furnace chamber suspended in elevated room (crucible) at the center of the complex. The sun’s energy is so concentrated within this chamber that temperatures can reach in excess of 3,000°C (5,420°F), but can also be controlled to lower temperatures (800°C) depending on the material being tested. The maximum temperature is about twice what a space vehicle experiences on atmospheric reentry, making the solar furnace an ideal platform for testing materials used in spaceflight. The tiles used to protect the space shuttle on reentry, for example, are made to withstand temperatures of just 1,260 °C (2,300 °F).
The only other way temperatures of this magnitude could be produced would require an astronomical amount of energy. The solar furnace is unique in that it doesn’t need to draw power from any outside source. The facility is therefore totally energy self sufficient, from the perimeter lights to the refrigerator in the break room, the solar furnace produces all the power it needs to operate, and conduct scientific experiments.
Until recently, the Parkent Solar Furnace was a heavily guarded and strictly off limits facility. The legacy of top-secret Soviet military space projects took a while to wear off. Today the furnace recognizes its potential as an educational and tourist attraction, so is now open for school visits, as well as group and individual tours. Friendly scientists who work at the facility also double as tour guides, giving visitors unprecedented access.
The Soviet era architectural aesthetic on display here is second only to the impressiveness of this still functioning research complex, where according to our guide, they are currently working with NASA on laser technologies for use in asteroid mining. When not testing the melting point of new metal alloys for the latest top-secret space plane, or roasting pinecones for tourists, the Solar Furnace was also used to light the Uzbek olympic flame as the starting off point for it’s recent journey to Pyeong Chang. 700 years removed from Amir Timur and the wonders of Samarkand, the Solar Furnace is just as interesting, if not more so than Registan Square, so it should definitely be on every traveler’s list of unusual places to visit in Uzbekistan.