Thermoelectric energy conversion in nanofluids for hybrid solar heat & power generator
|Contact: NAKAMAE Sawako, , firstname.lastname@example.org, +33 1 69 08 75 38/93 07
In proposed experimental internship, we will investigate the fundamental laws of physics behind the optical, thermal and thermoelectric properties of nanofluids. In parallel, the optimization and validation of the proof-of-concept hybrid solar-collector devices
will be conducted in order to demonstrate the co-generation feasibility of heat and electricity.
|Possibility of continuation in PhD: Oui
|Deadline for application:08/05/2024
Today, much of world’s consumed energy is lost to waste heat through all levels of human activity. For example, thermal loss consists 20 to 50 % of total energy consumption across different industrial sectors and as high as 60-70% in current gasoline and/or diesel powered. In such context, if even a small fraction of ‘waste-heat’ could be converted into more useful forms of energy (e.g., electrical, mechanical, etc.), it would result in tremendous savings to global energy consumption. Thermoelectric (TE) materials that are capable of converting heat into electricity have been considered as one possible solution to recover the low-grade waste-heat (from industrial waste-stream, motor engines, household electronic appliances or body-heat). The thermoelectric effect (the Seebeck effect) describes a material’s intrinsic property to directly convert temperature difference (dT) applied across its body into electric voltage (dV) and vice-versa; dV = -SedT, where Se is known as “the Seebeck coefficient.” So far, solid semiconductor-based materials are known to possess the highest thermal-to-electrical energy conversion efficiency, which is often expressed as a function of a dimensionless parameter ZT, called “figure of merit”: ZT = Se^2 T(s/k) where s and k are the electrical and thermal conductivities.
At SPHYNX, we explore thermoelectric effects in an entirely different class of materials, namely, complex fluids containing electrically charged nanoparticles that serve as both heat and electricity carriers. Unlike in solid materials, there are several inter-dependent TE effects taking place in liquids, resulting in Se values that are generally an order of magnitude larger than the semiconductor counterparts. While the precise origins of high Seebeck coefficients in these fluids are still debated, such liquids are already attracting attention as future TE-materials that are low-cost and environmentally friendly. One promising example of TE liquids is found in a hybrid solar collector capable for the co-generation of heat and electricity. The goal of this internship and the subsequent PhD project is two-fold. First, we will investigate the underlying laws of thermodynamic mechanisms behind the thermoelectric potential and power generation and other associated phenomena in nanofluids. More specifically, we are interested in how the particles' Eastman entropy of transfer is produced under the influence of thermal, electrical and concentration gradients. The results will be compared to their thermos-diffusive and optical abosrption properties to be obtained through research collaborations. Second, the project aims to test the promising nanofluids in the proof-of-concept hybrid solar-collector devices currently developed within the group to demonstrate the co-generation capability of heat and electricity. The hybrid device optimization is also within the project's scope. The proposed research project is primarily experimental, involving thermos-electrical, thermal and electrochemical measurements; implementation of automated data acquisition system and analysis of the resulting data obtained. The notions of thermodynamics, fluid physics and engineering (device) physics, as well as hands-on knowledge of experimental device manipulation are needed. Basic knowledge of optics and electrochemistry is a plus. For motivated students, numerical simulations using commercial CFD software, as well as the optical absorption measurements at the partner lab (LNO/CNR, Florence, Italy) can also be envisaged.
|Technics/methods used during the internship:
Transport measurements Electrochemical characterization Optical absorption/extinction (optional)
|Tutor of the internship