Specific fluid for converting light radiation to heat

1. A specific fluid suitable for converting solar light radiation to heat comprising:

liquid water; and

a filler in suspension in the liquid water, the filler comprising a strongly scattering powder of calcium carbonate which scatters light homogeneously through the liquid water to evenly heat the liquid water, the strongly scattering powder having a concentration by mass of between 1% and 3% and a median particle size of between 0.8 and 10 μm, particles of the strongly scattering powder having, on average, a light energy scattering coefficient of greater than 0.7.

2. The specific fluid according to claim 1 , wherein the strongly scattering powder has a median particle size of between 1 and 3 μm.

3. The specific fluid according to claim 1 , wherein the strongly scattering powder consists essentially of spheroidal particles.

4. The specific fluid according to claim 1 , wherein the strongly scattering powder has a CIE whiteness, measured according to DIN 6174, such that a parameter L* is equal to a value between 94 and 98, and such that a parameter a* is equal to a value between 0.1 and 1.5, and such that a parameter b* is equal to a value between 0.5 and 4, and combinations thereof.

5. The specific fluid according claim 1 , further comprising antifreeze, wherein a concentration by mass of antifreeze is between 0%, limit excluded, and 40%, limit included.

6. The specific fluid according to claim 1 , wherein the specific fluid has an energy absorptivity of between 0.1 and 10 cm −1 for solar radiation, the energy absorptivity defined as the amount of light which is absorbed by the specific fluid as a function of the distance into the specific fluid.

7. The specific fluid according to claim 1 further comprising a surfactant, wherein a concentration by mass of surfactant is between 0%, limit excluded, and 3%, limit included.

8. The specific fluid according to claim 1 further comprising an antifoam, wherein a concentration by mass of antifoam is between 0%, limit excluded, and 3%, limit included.

9. The specific fluid according to claim 1 , wherein the concentration by mass of strongly scattering powder is 3%, the specific fluid further comprising antifreeze having a concentration by mass of 30%, a surfactant having a concentration by mass of between 0.2% and 0.3% and an antifoam having a concentration by mass of between 0.2% and 0.3%.

10. The specific fluid according to claim 1 further comprising a bactericidal product.

11. Use of a specific fluid according to claim 1 , in a device for converting light radiation to heat, in which a light ray is directed towards the specific fluid, the specific fluid being a site of energy conversion.

12. A device for converting solar light radiation to heat, comprising a specific fluid configured to receive light radiation so as to be evenly heated throughout a liquid volume due to homogenous scattering of light, wherein the specific fluid is according to claim 1 .

13. The device according to claim 12 , comprising a solar collector.

14. The device according to claim 13 , wherein the device is a domestic water heater for heating water for a residence, wherein

the specific fluid circulates in channels of the solar collector to expose the specific fluid to light radiation, and wherein

the solar collector is configured to direct the light radiation to the specific fluid and to expose the specific fluid to the light radiation.

15. The device according to claim 14 , wherein the specific fluid has an energy absorptivity of between 0.1 and 10 cm −1 for solar radiation, the energy absorptivity defined as the amount of light which is absorbed by the specific fluid as a function of the distance into the specific fluid.

16. The specific fluid according to claim 1 , wherein the calcium carbonate is equal to or greater than 98% pure.