Investigation of Radiative Cooling Using a Photonic Composite Material for Water Harvesting

Authors

1 School of Mechanical and Building Sciences, VIT University, Chennai, India

2 School of Engineering Technology, Jain University, Bangalore, India

Abstract

The objective of this study is to design and analyse materials which are capable of harvesting water from thin air using condensation phenomenon which employs the radiative cooling approach. These passive cooling materials not only solve the water generating problems, but also employed in various cooling applications. The fundamental concept of radiative cooling is analysed and the performance parameters were identified to test the passive cooling ability of the designed material for water harvesting. The field of Photonics is studied which has the potential to obtain the surface temperature significantly lower than the atmospheric temperature by radiation phenomenon. Important parameters are identified to validate the performance of the proposed materials. ANSYS FLUENT is used to analyse the surface temperature for the given boundary conditions and the potential material which is capable of obtaining a significant temperature difference with respect to the ambient temperature is identified. A sandwich material is designed and its performance is evaluated using Computational Fluid Dynamics (CFD) by which we could achieve temperature difference of 15°C. To reduce the heat gain losses by conduction and convection, we designed a physical system which could maintain significant temperature difference even in the broad day-sunlight. CFD analysis of the designed system under similar boundary conditions gave satisfying results of maintaining the temperature difference of about 15°C for a prolonged period of time due to minimal heat gain losses. Later, two potential materials are manufactured and the performance parameters of these materials are characterized using U-V/Vis (Ultraviolet-Visible) and FTIR (Fourier Transform Infrared) Spectroscopy experiments. The results of absorption phenomenon in the U-V/Vis spectrum and the transmittance phenomenon in the FTIR spectrum of the two materials explain the reason for the passive cooling ability of materials.

Keywords


1.     Raman, A.P., Anoma, M.A., Zhu, L., Rephaeli, E. and Fan, S., "Passive radiative cooling below ambient air temperature under direct sunlight", Nature,  Vol. 515, No. 7528, (2014), 540-544.
2.     Hossain, M. and Gu, M., "Radiative cooling: Principles, progress, and potentials", Advanced Science,  Vol. 3, No. 7, (2016), 1500360 (1-10).
3.     Michell, D. and Biggs, K., "Radiation cooling of buildings at night", Applied Energy,  Vol. 5, No. 4, (1979), 263-275.
4.     Harrison, A. and Walton, M., "Radiative cooling of TiO2 white paint", Solar Energy,  Vol. 20, No. 2, (1978), 185-188.
5.     Johnson, T., "Radiation cooling of structures with infrared transparent wind screens", Solar Energy,  Vol. 17, No. 3, (1975), 173-178.
6.     Givoni, B., "Solar heating and night radiation cooling by a roof radiation trap", Energy and Buildings,  Vol. 1, No. 2, (1977), 141-145.
7.     Catalanotti, S., Cuomo, V., Piro, G., Ruggi, D., Silvestrini, V. and Troise, G., "The radiative cooling of selective surfaces", Solar Energy,  Vol. 17, No. 2, (1975), 83-89.
8.     Berdahl, P., Martin, M. and Sakkal, F., "Thermal performance of radiative cooling panels", International Journal of Heat and Mass Transfer,  Vol. 26, No. 6, (1983), 871-880.
9.     Nilsson, T.M.J., "Using radiative cooling to condense air moisture: Review and theory", in Internal report, Institute of Physics, Chalmers University of Technology, GIPR-321 0380 2872., (1994).
10.   Nilsson, T.M., "Optical scattering properties of pigmented foils for radiative cooling and water condensation: Theory and experiment, Chalmers University of Technology,  (1994).
11.   Nilsson, T.M., Niklasson, G.A. and Granqvist, C.G., "A solar reflecting material for radiative cooling applications: Zns pigmented polyethylene", Solar Energy Materials and Solar cells,  Vol. 28, No. 2, (1992), 175-193.
12.   Nilsson, T., "Initial experiments on dew collection in sweden and tanzania", Solar Energy Materials and Solar Cells,  Vol. 40, No. 1, (1996), 23-32.
13.   Al-Nimr, M., Kodah, Z. and Nassar, B., "A theoretical and experimental investigation of a radiative cooling system", Solar Energy,  Vol. 63, No. 6, (1998), 367-373.
14.   Nilsson, T.M., Vargas, W.E. and Niklasson, G.A., "Pigmented foils for radiative cooling and condensation irrigation", in Optical Materials Technology for Energy Efficiency and Solar Energy Conversion XIII, International Society for Optics and Photonics. Vol. 2255, (1994), 193-204.
15.   Beysens, D., Clus, O., Mileta, M., Milimouk, I., Muselli, M. and Nikolayev, V., "Collecting dew as a water source on small islands: The dew equipment for water project in Bis evo (croatia)", Energy,  Vol. 32, No. 6, (2007), 1032-1037.
16.   Granqvist, C., "Radiative heating and cooling with spectrally selective surfaces", Applied Optics,  Vol. 20, No. 15, (1981), 2606-2615.
17.   Granqvist, C. and Hjortsberg, A., "Radiative cooling to low temperatures: General considerations and application to selectively emitting SiO films", Journal of Applied Physics,  Vol. 52, No. 6, (1981), 4205-4220.
18.   Eriksson, T. and Granqvist, C., "Radiative cooling computed for model atmospheres", Applied Optics,  Vol. 21, No. 23, (1982), 4381-4388.
19.   Clus, O., Muselli, M., Beysens, D., Nikolayev, V. and Ouazzani, J., "Computational fluid dynamic (CFD) applied to radiative cooled dew condensers", in Environment Identities and Mediterranean Area. ISEIMA'06. First international Symposium on, IEEE., (2006), 217-221.
20.   Clus, O., Ouazzani, J., Muselli, M., Nikolayev, V., Sharan, G. and Beysens, D., "Comparison of various radiation-cooled dew condensers using computational fluid dynamics", Desalination,  Vol. 249, No. 2, (2009), 707-712.
21.   Bahreini, S., Nassab, S.G. and Addini, M.M., "Inverse boundary design problem of combined radiation-convection heat transfer in laminar recess flow", International Journal of Engineering-Transactions C: Aspects,  Vol. 29, No. 3, (2016), 394-402.
22.   Rahnama, M., Djavidi, M., Mansouri, S.H. and Sinaie, A., "Numerical investigation of combined radiation and natural convection heat transfer in a horizontal annulus", International Journal of Engineering-Transactions C: Aspects,  Vol. 12, No. 4, (1999), 259-270.