Thermal characterization of full-scale PCM products and numerical simulations, including hysteresis, to evaluate energy impacts in an envelope application

• Published in: Applied thermal engineering Vol. 138; no. C; pp. 501 - 512
• Main Authors: Biswas, Kaushik, Shukla, Yash, Desjarlais, Andre, Rawal, Rajan
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 25.06.2018; Elsevier BV; Elsevier
• Subjects: 2D wall model with PCM; ASTM C1784; Computer simulation; ENGINEERING; Enthalpy; Fatty acids; Freezing; Heat flow meter apparatus; Heat transmission; Hysteresis; Melting; Numerical analysis; PCM characterization; PCM hysteresis modeling; Temperature; Temperature dependence; Test procedures; Thermal storage; Thermodynamic properties; Thermodynamics; Two dimensional models; Heat flow meter apparatus; ASTM C1784; PCM hysteresis modeling; 2D wall model with PCM; PCM characterization
• ISSN: 1359-4311; 1873-5606
• DOI: 10.1016/j.applthermaleng.2018.04.090

•Performed thermal characterization of full-scale PCM products.•Utilized a heat flow meter apparatus for PCM characterization.•Performed annual simulations using a 2D wall model with a PCM layer.•Evaluated the impact of hysteresis on the annual energy performance of a PCM. This article presents combined measurements of fatty acid-based organic PCM products and numerical simulations to evaluate the energy benefits of adding a PCM layer to an exterior wall. The thermal storage characteristics of the PCM were measured using a heat flow meter apparatus (HFMA). The PCM characterization is based on a recent ASTM International standard test method, ASTM C1784. The PCM samples were subjected to step changes in temperature and allowed to stabilize at each temperature. By measuring the heat absorbed or released by the PCM, the temperature-dependent enthalpy functions for melting and freezing were determined. The simulations were done using a previously-validated two-dimensional (2D) wall model containing a PCM layer and incorporating the HFMA-measured enthalpy functions. The wall model was modified to include the hysteresis phenomenon observed in PCMs, which is reflected in different melting and freezing temperatures of the PCM. Simulations were done with a single enthalpy curve based on the PCM melting tests, both melting and freezing enthalpy curves, and with different degrees of hysteresis between the melting and freezing curves. Significant differences were observed between the thermal performances of the modeled wall with the PCM layer under the different scenarios.