Forced Convection of Nanofluid-Microencapsulated Phase Change Material Mixtures in Mini-Channels: Importance of the Mini-Channel Height

Abstract

Energy storage and heat enhancement are the main focus of many projects in the industry. Phase change material is receiving a lot of interest in the energy sector. In particular, storing energy for later use or heat extraction has been the focus of many types of research in this field. Nanofluid and microencapsulated phase change material (MEPCM) flow is an exciting field, mainly when the mixture fluid circulates in mini channels. Many applications, including cooling surfaces, have been investigated. This paper examines how to store energy without using extra space for a particular design. Four different fluids are circulating in mini-channels which are distilled water, 0.5%vol Al2O3 in water, 0.5% Al2O3 +4% MEPCM/water, and 0.5% Al2O3 +20% MEPCM/water. The flow is assumed laminar and steady-state. Results revealed that the amount of energy absorbed when using 0.5% Al2O3 +20% MEPCM/water mixture exceeds 0.5%vol Al2O3 in the water mixture. By varying the mini-channels heights, maintaining constant test volume of the cavity, it was found that the flow in the minichannels and above the mini-channels exhibit the more extensive heat removal capacity. This occurs when the mini-channels height occupies half the test cavity height corresponding to an aspect ratio equal to 6. Among the four fluids under investigation, 0.5% Al2O3 +20% MEPCM/water is the most effective fluid for heat removal and energy storage.