Thermophysical Properties of POLWAX LTP ST Paraffin Doped with or without Carbon Nanotubes or Silver Nanowires and Passive Cooling of a High-Power LED Panel

Commercially available paraffin wax LTP ST, manufactured in Poland by POLWAX, was used as a phase change material (PCM) for passive cooling of an LED panel containing 28 high power light emitting diodes (LEDs). Paraffin wax LTP ST of density ρ = 930 kg·m−3 at room temperature (RT) was chosen over ot...

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Bibliographic Details
Published in:Energies (Basel) 2023-08, Vol.16 (16), p.6068
Main Authors: Zmywaczyk, Janusz, Zbińkowski, Piotr, Koniorczyk, Piotr
Format: Article
Language:English
Subjects:
Alloys
Carbon
carbon nanotubes
Computer software industry
Cooling
Electric properties
Energy storage
Graphene
Heat conductivity
heat sinks
Heat transfer
Hydrocarbons
Light emitting diodes
Nanoparticles
Nanotubes
Nanowires
panel LEDs
paraffin wax LTP ST
passive cooling
phase change material PCM
Silver
Temperature
Thermal energy
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Summary:Commercially available paraffin wax LTP ST, manufactured in Poland by POLWAX, was used as a phase change material (PCM) for passive cooling of an LED panel containing 28 high power light emitting diodes (LEDs). Paraffin wax LTP ST of density ρ = 930 kg·m−3 at room temperature (RT) was chosen over other POLWAX waxes (LUXOLINA, LUXOLINA-ST, and LTP 56-20) because of its melting point range (44.5–55.4 °C), relatively high latent heat of fusion ΔH = 218.8 J·g−1, high specific heat Cp = 2.11 J·g−1K−1 and thermal conductivity k = 0.233 Wm−1K−1 at 0 °C. The thermophysical properties were studied in samples of pure LTP ST paraffin and doped with multi-walled carbon nanotubes (1.99, 3.49, 5.35, and 10.49 wt%, MWCNTs) or silver nanowires (0.26, 0.32, 1.06, 2.10, and 7.35 wt%, SNWs). Analysis of the thermal effects of doped samples showed a relative increase in the degree of subcooling, averaging 100% for MWCNT and 46% for SNW, a relative 15÷25% decrease in enthalpy of melting for MWCNT and 14÷16% for SNW. A 44% increase in thermal conductivity was found for the sample containing 5.35 wt% MWCNTs and a 91% increase for 1.06 wt% SNW. The results of cooling efficiency tests for three types of developed heat sinks fabricated of AW-2017A aluminum alloy are presented, i.e., (a) full system without PCM filling, (b) system with PCM chamber without intracellular ribs, (c) and system with PCM chamber with intracellular fins.
ISSN:1996-1073
1996-1073
DOI:10.3390/en16166068