NON-INTRUSIVE MEASUREMENTS OF THE PHASE CHANGE PROCESS IN ENERGY STORAGE SYSTEMS
Abstract
The solid-liquid phase change is the most common morphological change in thermal energy storage (TES) systems due to the high densification and small phase change volume change of solid-liquid PCM (Huang et al., 2017; Praveen et al., 2019). Many transient applications of photovoltaic devices, building applications, solar water heating, greenhouse heating, microelectronics, satellite power testing in space, etc. have recently tried to take advantage of phase change material (PCM) for a cooling solution as a latent heat energy storage device by changing phase during melting-freezing process without raising the temperature. PCM s high heat removal capabilities can be attractive for transient applications that last only a short period with a chance to recharge (solidify) between pulses. However, there is a general problem of low thermal conductivity and low thermal charging and discharging efficiency. Numerous studies have been devoted to developing different techniques and strategies to optimize PCM thermal conductivity and shorten the phase transition time so that PCM can fully exploit its role in TES systems. A practical method of improving the melting-freezing rate is to incorporate a porous insert (e.g., foams, fins, random structure, and heat sinks) inside the PCM to take advantage of the higher thermal conductivity of porous inserts. Since the composite PCM can be used for thermal energy storage and temperature control, the thermo-fluidic characteristics are apparently of fundamental importance for the performance evaluation in the practical application. In the current project, the flow and heat transfer characteristics during the melting of a composite PCM will be experimentally investigated, where paraffin wax will be used as the phase change material, and different techniques will be tested to enhance the PCM thermal conductivity. The evolution of the solid-liquid phase boundary will be visualized; a particle image velocimetry and an infrared camera will capture the flow and temperature field, respectively. The research group at Instituto Tecnológico de Aeronautica (ITA) will experimentally investigate and optimize the thermal behavior of copper foam-PCM composite under uniform heat flux boundary conditions. The geometrical characteristics of the foam, such as porosity, PPI, and orientation effects, will be considered; moreover, the velocity field in the liquid PCM will be measured with particle image velocimetry (PIV) technique, while infrared thermography technology will measure the temperature field. Moreover, research activities will be aimed at the experimental investigation of phase change materials (PCMs) embedding extended surfaces such as fins. The transient flow and thermal behavior of PCM melting will be analyzed using particle image velocimetry (PIV) and infrared camera technology to capture the flow and temperature field during phase change.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Feb 06, 2025
- Source ID
- FA95502510031
Entities
People
- Guilherme S Ribeiro
Organizations
- Air Force Office of Scientific Research
- United States Air Force