rexresearch
S. CHOI, et al.
Coffee Nanocolloid Heat Transfer
https://revolution-green.com/coffee-based-colloids-direct-solar-absorption/
Coffee-based colloids for direct solar absorption
...In a recent study, Matteo Alberghini and co-workers at the Departments of Energy, Applied Science and Technology, and the National Institute of Optics in Italy, investigated a sustainable, stable and inexpensive colloid based on coffee solutions to implement direct solar absorption. Results of their work are now published on Scientific Reports... the colloid consisted of distilled water, Arabica coffee, glycerol and copper ssulphate to optimize the properties and biocompatibility of the fluid. The scientists analyzed the photothermal performance of the proposed fluid for direct solar absorption and compared its performance with traditional flat-plate collectors. They showed that the collectors could be precisely tailored and realized with 3-D printing for the experimental tests...
https://www.nature.com/articles/s41598-019-39032-5
Scientific Reports, volume 9, Article number: 4701 (2019)
Coffee-based colloids for direct solar absorption
Matteo Alberghini, et al.
[ PDF ]
Abstract -- Despite their promising thermo-physical properties for direct solar absorption, carbon-based nanocolloids present some drawbacks, among which the unpleasant property of being potentially cytotoxic and harmful to the environment. In this work, a sustainable, stable and inexpensive colloid based on coffee is synthesized and its photo-thermal properties investigated. The proposed colloid consists of distilled water, Arabica coffee, glycerol and copper sulphate, which provide enhanced properties along with biocompatibility. The photo-thermal performance of the proposed fluid for direct solar absorption is analysed for different dilutions and compared with that of a traditional flat-plate collector. Tailor-made collectors, opportunely designed and realized via 3D-printing technique, were used for the experimental tests. The results obtained in field conditions, in good agreement with two different proposed models, show similar performance of the volumetric absorption using the proposed coffee-based colloids as compared to the classical systems based on a highly-absorbing surface. These results may encourage further investigations on simple, biocompatible and inexpensive colloids for direct solar absorption.
https://www.osti.gov/biblio/196525-enhancing-thermal-conductivity-fluids-nanoparticles
OSTI.GOV Conference: Enhancing thermal conductivity of fluids with nanoparticles
Enhancing thermal conductivity of fluids with nanoparticles
Choi, S.U.S.; Eastman, J.A.
Abstract -- Low thermal conductivity is a primary limitation in the development of energy-efficient heat transfer fluids that are required in many industrial applications. In this paper we propose that an innovative new class of heat transfer fluids can be engineered by suspending metallic nanoparticles in conventional heat transfer fluids. The resulting nanofluids are expected to exhibit high thermal conductivities compared to those of currently used heat transfer fluids, and they represent the best hope for enhancement of heat transfer. The results of a theoretical study of the thermal conductivity of nanofluids with copper nanophase materials are presented, the potential benefits of the fluids are estimated, and it is shown that one of the benefits of nanofluids will be dramatic reductions in heat exchanger pumping power.
US6221275 -- Enhanced heat transfer using nanofluids
Abstract -- This invention is directed to a method of and apparatus for enhancing heat transfer in fluids such as deionized water. ethylene glycol, or oil by dispersing nanocrystalline particles of substances such as copper, copper oxide, aluminum oxide, or the like in the fluids. Nanocrystalline particles are produced and dispersed in the fluid by heating the substance to be dispersed in a vacuum while passing a thin film of the fluid near the heated substance. The fluid is cooled to control its vapor pressure.