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AORA's Tulip solar power system is more than hot air


April 4, 2012

AORA's Tulip system uses the sun's rays to heat air, which is then used to spin a turbine, creating electricity

AORA's Tulip system uses the sun's rays to heat air, which is then used to spin a turbine, creating electricity

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A giant flower has recently sprung up near the southern Spanish city of Almeria. Measuring 35 meters (115 feet) high, the Tulip is the product of Israeli company AORA, and it uses heat from the sun to generate electricity. Work began on the hybrid concentrating solar power technology back in the 80s and the first Tulip pilot plant was installed at Israel’s Kibbutz Samar in 2009. That setup has been pumping electricity into the country’s power grid every year since. The Spanish plant was completed this January.

The scalable, modular system incorporates 52 mirrors – or heliostats – which are arranged on the ground around the base of the Tulip. They turn to track with the sun, reflecting and concentrating its rays onto the plant’s top-mounted “bulb” at all times of the day. This causes the air inside the bulb to heat to temperatures as high as 1,000ºC (1,832ºF). That ultra-hot air is then used to run a turbine generator.

The plant has an output capacity of 100 kilowatts-equivalent – reportedly enough to power 60 to 80 homes.

Unlike some other systems that use water, oil or mineral salts as their solar heat-carrying medium, the Tulip uses atmospheric air. It also doesn't require any cooling medium – an important consideration in areas where water is scarce. At night, when there’s no warming sunlight, it can be switched over to generate electricity using fuels such as diesel or natural gas – it can even operate in a hybrid mode when the sunlight is intermittent, using both fuel and solar-heated air at the same time.

The Almeria plant took approximately seven months to build, and is designed to operate for at least 25 years. AORA hopes to have additional demonstration plants operational in other parts of the world soon.

The AORA video below provides a run-down on the workings of the Tulip plant.

Source: AORA

About the Author
Ben Coxworth An experienced freelance writer, videographer and television producer, Ben's interest in all forms of innovation is particularly fanatical when it comes to human-powered transportation, film-making gear, environmentally-friendly technologies and anything that's designed to go underwater. He lives in Edmonton, Alberta, where he spends a lot of time going over the handlebars of his mountain bike, hanging out in off-leash parks, and wishing the Pacific Ocean wasn't so far away. All articles by Ben Coxworth

So in theory they could heat up the air with geothermal too?

Carlos Grados

The hybrid model is much more practical than any stored energy system.


re; Carlos Grados

There are more efficient ways of converting geothermal energy into mechanical energy than through a heat exchanger into air that is running through a gas turbine. Stirling cycle springs to mind. Also tappable geothermal usually is not nearly that hot.


Basically this is a jet engine with an extended turbine shaft between the compressor and the expandor stages, using a solar concentrated air heater, instead of a combuster.

I have been designing this kind of gear for years...

Kudos - simple and if you use a closed loop cycle on the air, you can use all that heat energy for other purposes.

Mr Stiffy

re; Mr Stiffy

If you use a closed loop you loose efficiency in the generation of electricity.


Slowburn, If one were to use the high(er) temp exhaust to preheat the medium prior entering the target receiver, wouldn't that INCREASE the overall efficiency?


Apparently, NIMBY doesn't exist in these other countries. Good for them! I am curious as to why a brine solution or even some hypertutechtic salt isn't used, only because of the btu/volume. Even a Rankine cycle would seem better by definition. I defer to you, Mr. Stiffy, as you design these, I hope you could shed light on this curiosity.



NO - you extract the heat out of the working fluid for other purposes......

Mr Stiffy

re; Burnerjack

Yes. It is a fairly common design feature on large ground based gas turbines but it is still on open system.


System efficiency is in 'how much energy you can take out in a cycle'. If air is heated to 1000 degrees, and cooled to 200 during the power stroke, then reheated, 800 degrees of power is taken out every cycle. Very efficient.

The re-heating is the problem. Energy transfers to liquid (coefficient of conductivity) at an rate of '1' and to air at an rate of '.5'. very inefficient.

If your energy is free, however, it works.


re; blue7053

System efficiency is in 'how little of the energy is lost to entropy.

With the turbine design it is a preheat.

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