A liquid fuel able to store the energy of the sun up to 18 years

[izentrop]

Do not laugh it looks serious, would it be a revolution if it really works? https://www.popscience.fr/des-scientifi ... u-a-18-ans

Swedish scientists have developed a specialized fluid, called solar thermal fuel, capable of storing solar energy for more than ten years.

"A solar thermal fuel is like a rechargeable battery, but instead of electricity, you bring in sunlight and out heat, triggered on demand," says Jeffrey Grossman, an engineer who works with these materials explained. at NBC News.

Fluid is a molecule in liquid form Scientists at Chalmers University of Technology in Sweden have been improving for over a year.

This molecule is composed of carbon, hydrogen and nitrogen, and when it is struck by sunlight, it has an unusual effect: the bonds between its atoms are rearranged and it turns into an energized new version of it. same, called an isomer.

Like prey trapped in a trap, the sun's energy is captured between the strong chemical bonds of the isomer and stays there even when the molecule cools to room temperature.

When energy is needed - for example at night or in winter - the fluid is simply drawn through a catalyst that brings the molecule back to its original form, releasing energy in the form of heat.

"The energy in this isomer can now be stored for up to 18 years," says Kasper Moth-Poulsen, a nanomaterials scientist at Chalmers University, is part of the team.

The emission-free renewable energy device consists of a concave reflector with a pipe in the center, which follows the sun as a kind of satellite dish.

The system operates in a circular fashion. By pumping through transparent tubes, the fluid is heated by sunlight, transforming the norbornadiene molecule into its heat-trapping isomer, the quadricyclane. The fluid is then stored at room temperature with minimal energy loss.

When energy is needed, the fluid is filtered through a special catalyst that reconverts the molecules back to their original form, warming the liquid to 63 ° C.

The researchers subjected the fluid to this cycle more than 125 times, capturing heat and dropping it without damaging the molecule.

"We have made many crucial advances recently and today we have a zero emissions energy system that operates year round," says Moth-Poulsen.

After a series of rapid developments, researchers say their fluid can now hold 250 watt hours of energy per kilogram, which doubles the energy capacity of Tesla's Powerwall batteries, according to NBC.

But there is still a lot to do. With the right manipulations, the researchers think they can get even more heat from this system, at least 110 ° C more.

“There is still a lot to do. We just got the system up and running. Now we need to make sure everything is optimally designed,” says Moth-Poulsen.

If everything goes as planned, Moth-Poulsen thinks the technology might be available for commercial use in 10 years ago.

In 10 years it may be too late.

[sen-no-sen]

If I understood correctly, this is a process similar to that used in heaters whose heat can be released by cracking a metal pellet in a supersaturated solution of sodium acetate, but here it is is in "Super" mode.

[thibr]

interesting but
to test only 125 times that seems little?
that would be even ridiculous on a battery
I am surprised that there is not a continuous test to test in lab with small amount
they do not talk about performance at all?

[sen-no-sen]

interesting but
to test only 125 times that seems little?

This roughly corresponds to the life of a quality heater.

[thibr]

they leave from afar ...
The efficient storage of solar energy is a major challenge for a sustainable future. For this reason, molecules capable of storing solar energy and releasing them via valence isomerization, for what is known as the molecular storage of solar thermal energy (MOST), have been studied. Energy storage by photoconversion of the photothermal couple dihydroazulene / vinylheptafulvene (DHA / VHF) was evaluated. The robust nature of this system is determined by multiple cycles of storage and release of energy at high temperatures in three different solvents. In a non-polar solvent such as toluene, the DHA / VHF system can be cycled more than 70 times with less than 0,01% degradation per cycle. In addition, the conversion catalyzed by [Cu (CH 3 CN) 4] PF 6 from VHF to DHA was demonstrated in a flow reactor. The performances of the DHA / VHF pair have also been evaluated in prototypes of photoconversion devices, both in the laboratory, using a flow chip under simulated solar light and outdoors, with a parabolic mirror. Experiments on the devices have demonstrated a storage efficiency of solar energy up to 0,13% in the chip device and up to 0,02% in the parabolic collector. Tracks for future improvements and system optimization are also discussed.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5655704/

[Exnihiloest]

They announce 250 Wh / Kg, which they say is double of a Tesla battery. For me that's what Tesla batteries are already doing. Nevertheless, the energy density remains very interesting.
But I'm wary of loud announcements, we have almost every week on physics sites, most of which we never hear spoken next.

The problem here is clear: the energy supplied in return is not electricity but thermal energy, and the temperature supplied is far too low to obtain an efficient transformation in electricity, because of the Carnot cycle. Even with a stirling engine, the overall efficiency of the process would be very poor.
In a pinch for heating or hot water, the process could be interesting, but as the sun in winter can not already properly heat a house during the day, I'm afraid we have no surplus to stock during this time...

[izentrop]

they do not talk about performance at all?

In a May 2018 publication https://www.nature.com/articles/s41467-018-04230-8

Molecular photocouplers can be used for the storage of solar thermal energy by photoisomerization to high energy metastable isomers; We present a molecular design strategy leading to high energy density, long storage time photoelectric switches. Measured energy densities up to 559 kJ kg -1 (155 Wh kg -1), long storage times up to 48,5 days and high quantum conversion efficiencies of up to 94% per subunit are shown in norbornadiene / quadricyclane (NBD / QC) photocouplings / thermo-switches incorporated in dimeric and trimeric structures.

quantum efficiency?
It is also cobalt catalysts, which as for the fuel cell is less interesting, cobalt being a rare and expensive metal.

The experiments on the devices have demonstrated a storage efficiency of solar energy up to 0,13% in the chip device and up to 0,02% in the parabolic collector.

What is the relationship with performance?
The ratio stored energy / m² would be more speaking and could be compared to photovoltaic.

They announce 250 Wh / Kg,

One could imagine a fuel manufactured near the equator, used as refillable gas cylinders but lighter, since not under pressure ..

[Exnihiloest]

... One could imagine a fuel manufactured near the equator, used as refillable gas cylinders but lighter, since not under pressure.

The idea is good but unfortunately the energy density is insufficient.
For petrol, the density is around 13 KWh / Kg, so it can be transported far while remaining profitable, tankers are justified. With this new fuel, you would have to transport 52 times more weight for the same energy, it's no longer going ...