Latent heat thermal energy storage systems have various advantages over sensible heat-based systems. The inclusion of the latent energy of the storage media through phase change increases the energy density of the system and narrows the range of operating temperatures. However, solid-to-liquid phase change is not yet well understood, which limits the ability to design efficient systems for their use.The generally accepted method to experimentally measure temperature within a phase change material (PCM) is the use of one or many thermocouples. The most detailed studies involve a high-resolution grid of thermocouples inserted into the PCM domain. The invasiveness of the technique introduces error into the measurement, as the thermocouples interfere with the flow behaviour, can introduce heat leakage, and as they cannot be placed directly onto a boundary due to local thermal non-equilibrium, there will always be data loss in the near-wall region. Also, many thermocouples can decrease the reliability of an experimental setup as insertion through a boundary can cause issues with leakage. Although thermal imaging has been used in some studies, it is only used to measure surface temperature.This study investigates the viability of using infrared imaging to non-invasively gain insight into the internal temperatures when a thin, near 2D PCM geometry is used, as is the case with many PCM studies. A high-resolution grid of thermocouples was installed in a thin circular cavity filled with PCM and was compared to the data measured by the infrared camera through the front surface. The cavity was surrounded by a water jacket, which was used as the heating and cooling source. The testing was conducted at three heating and three cooling conditions, that correspond to PCM melting and freezing cases, respectively. Results show that the use of infrared imaging alone is a viable technique for internal temperature measurement in situations where long experimental time scales are involved. Detailed results will be presented at the conference.

Thermal Imaging for Non-Invasive Temperature Measurement in Thin Fluid Encapsulations

Paper Proceedings: https://asmedigitalcollection.asme.org/FEDSM/FEDSM2021/volume/85284

ASME 2021 Fluids Engineering Division Summer Meeting (FEDSM2021)

Supporting the need among researchers worldwide for additional online and multimedia content, ASME now offers the ASME Conference Video Collection. This platform will collect and provide long-term access to conference presentation videos, encompassing all technology areas within ASME's technical conference and events program. About 30,000-40,000 engineers across all mechanical engineering and related disciplines participate in ASME conferences each year. This includes authors of approximately 6,000 to 8,000 technical papers published by ASME, the majority of whom also submit video presentations for our virtual conferences. The video collection will be available as an add-on to existing product packages or as a separate subscription.