Nano-Scale Phase Change Materials (Pcm’s) and Their Effect on Heat Transfer Fluids
Nano-scale Phase Change Materials (PCM’s) and Their Effect on Heat Transfer Fluids
Sean Schulte, Chaoming Wang, Ming Su
1NanoScience Technology Center, 2Department of Mechanical, Materials, and Aerospace Engineering, University of Central Florida, Orlando, Florida 32826. mingsu@mail.ucf.edu Abstract:
Introduction:
Heat transfer fluids (HTF’s) are often used as carriers in heat transfer equipment. It therefor comes as no surprise that finding a way to make HTF’s more efficient is desirable in the scientific community. Research is being done to attempt to rectify this issue by adding materials with a high thermal conductivity (metal’s and metal oxides) to HTF’s in accordance with Maxwell’s heat transfer equations [1]. Until recently this problem was addressed by using micro scale solid particles with millimeter sizes which were blended into the HTF’s. Unfortunately problems which include abrasion, clogging, phase separation etc. occurred which limits the practical application of this technique [2]. To attempt to rectify this Choi introduced what he referred to as nanofluids [3]. Nano particles were suspended in heat transfer fluids to attempt to increase the thermal conductivity of the heat transfer fluids. The effectiveness of this approach has been widely debated amongst the scientific community. In 2009 a study consisting of over 30 organizations was published in the Journal of Applied Physics [5]. The aim of this study was to test the thermal conductivity of nanofluids using various methods which include the transient hot wire method, steady-state methods, and optical methods. The results seemed to suggest no noticeable enhancement of thermal conductivity of the nanofluids. The purpose of this research is to create phase-change nano-particles (nano PCM’s) to increase the heat capacity of heat transfer fluids (HTF’s). Fluids have low heat conductivity and limited heat capacity and the phase change nano-particles are added due to their large
Sean Schulte, Chaoming Wang, Ming Su
1NanoScience Technology Center, 2Department of Mechanical, Materials, and Aerospace Engineering, University of Central Florida, Orlando, Florida 32826. mingsu@mail.ucf.edu Abstract:
Introduction:
Heat transfer fluids (HTF’s) are often used as carriers in heat transfer equipment. It therefor comes as no surprise that finding a way to make HTF’s more efficient is desirable in the scientific community. Research is being done to attempt to rectify this issue by adding materials with a high thermal conductivity (metal’s and metal oxides) to HTF’s in accordance with Maxwell’s heat transfer equations [1]. Until recently this problem was addressed by using micro scale solid particles with millimeter sizes which were blended into the HTF’s. Unfortunately problems which include abrasion, clogging, phase separation etc. occurred which limits the practical application of this technique [2]. To attempt to rectify this Choi introduced what he referred to as nanofluids [3]. Nano particles were suspended in heat transfer fluids to attempt to increase the thermal conductivity of the heat transfer fluids. The effectiveness of this approach has been widely debated amongst the scientific community. In 2009 a study consisting of over 30 organizations was published in the Journal of Applied Physics [5]. The aim of this study was to test the thermal conductivity of nanofluids using various methods which include the transient hot wire method, steady-state methods, and optical methods. The results seemed to suggest no noticeable enhancement of thermal conductivity of the nanofluids. The purpose of this research is to create phase-change nano-particles (nano PCM’s) to increase the heat capacity of heat transfer fluids (HTF’s). Fluids have low heat conductivity and limited heat capacity and the phase change nano-particles are added due to their large
References: 1. Maxwell, C. J., Electricity and Magnetism. Oxford : Clarendon Press: 1873. 2. Hong, Yan University of Central Florida (dissertation) 2011 3. Choi, S. U. S.; eastman, J. A. In Enhancing thermal conductivity of fluids with nanoparticles, Int. Mech. Eng. Cong. Exh., San Francisco, CA. 4. Nan, C. W.; Birringer, R.; Clarke, D. R.; Gleiter, H., Effective thermal conductivity of particulate composites with interfacial thermal resistance. J. Appl. Phys. 1997, 81, 6692. 5. Buongiorno, J.; Venerus, D.; Prabhat, N.; et al, A benchmark study on the thermal conductivity of nanofluids. J. Appl. Phys. 2009, 106. 6. T. Hawa, M.R. Zachariah; Coalescence kinetics of unequal sized nanoparticles. J. Aerosol Science, 2005. 7.