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ISSN Online: 2377-424X

ISBN Print: 978-1-56700-474-8

ISBN Online: 978-1-56700-473-1

International Heat Transfer Conference 16
August, 10-15, 2018, Beijing, China

CONTROL OF HEAT RELEASE ENERGY DURING HEATING FROM SOLID-SOLID PHASE CHANGE MATERIAL

Get access (open in a dialog) DOI: 10.1615/IHTC16.ecs.024007
pages 4425-4432

Abstract

The use of phase change materials (PCMs) as a heat source and storage has become an important consideration in energy management. 2-amino-2-methyl-1,3-propanediol (AMP), which is a solid-solid PCM, stores approximately 264 J/g of heat energy at approximately 78 °C. AMP has the attractive characteristic of storing heat energy in its non-equilibrium solid state. This study clarified this characteristic to control the stored heat energy of AMP so that it can be used at when heat energy is needed. The thermal property was measured by differential scanning calorimetry (DSC) in the temperature range of -50 °C to 100 °C, and the structural property was measured through X-ray powder diffraction in the temperature range of -70 °C to 90 °C. The results revealed that the material's initial crystal structure changed from brittle crystalline (phase II) to plastic crystalline (phase I) at 80 °C during heating from room temperature to 90 °C. Phase I remained almost unchanged during cooling from 90 °C to -50 °C, but changed to the non-equilibrium state (phase Ig'). Then, phase Ig' changed to phase II with exoergic heat of 140 J/g in the temperature range between -14 °C and 36 °C during heating. This study clarified that the phase change temperature can be controlled by controlling the sample mass or by applying an external stimulus. In other words, AMP is a rare solid-solid PCM that does not release heat energy during cooling, but rather releases heat energy during heating. Moreover, the heat energy is controllable. This positive attribute makes AMP a good candidate for use in a heating assist system.