Influence of Phase Change Materials (PCMs) on the thermal performance of building envelopes

To understand the influence of PCM wall configurations on the thermal performance of building envelopes, an explicit finite element model of heat transfer from indoor to outdoor (or vice versa) is developed. The accuracy of this model is first validated against the electrical circuit analogy model, and then compared with the experimental data measured in a Hot-Box device. A good agreement between the simulation results and experimental results is obtained. The results of this study show that the PCM configuration layer sequence significantly will affect the thermal performance of building envelopes and that the FEM model developed is a promising tool, which after some more development may be used for optimising PCM wall configurations.

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An Explicit Finite Element Method for Thermal Simulations of Buildings with Phase Change Materials

Energies ◽

10.3390/en14196194 ◽

2021 ◽

Vol 14 (19) ◽

pp. 6194

Author(s):

Hongxia Zhou ◽

Åke Fransson ◽

Thomas Olofsson

Keyword(s):

Finite Element Method ◽

Finite Element ◽

Phase Change ◽

Thermal Performance ◽

Phase Change Materials ◽

Electrical Circuit ◽

Building Envelopes ◽

Explicit Finite Element Method ◽

Explicit Finite Element ◽

Element Method

The thermal performance of building envelopes is essential for building thermal comfort and the reduction of building energy requirements. Phase change materials (PCMs) implemented in building envelopes can improve thermal performance. An explicit finite element method (ex-FEM) has been developed based on a previous study to investigate the heat transfer performance through building walls with installed PCMs. For verification, we introduce an electrical circuit analogy (ECA) method. For model validation, at first, COMSOL is used. For comparison, data were collected from experiments using a small hotbox, part of the sides are covered by PCMs with different configurations. This work shows how the ex-FEM model can predict the wall’s temperature profile with and without incorporated PCM. With the implementation of PCMs, the work problematizes unpredictable influences for modeling. In addition, the study introduces results from simulations of sequencing of PCM layers in wall construction.

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Stress Intensity of Delamination in a Sintered-Silver Interconnection

Additional Conferences (Device Packaging HiTEC HiTEN & CICMT) ◽

10.4071/hitec-wa26 ◽

2014 ◽

Vol 2014 (HITEC) ◽

pp. 000190-000197 ◽

Cited By ~ 5

Author(s):

D. J. DeVoto ◽

P. P. Paret ◽

A. A. Wereszczak

Keyword(s):

Stress Intensity ◽

Power Electronics ◽

Thermal Performance ◽

Phase Change Materials ◽

Coefficient Of Thermal Expansion ◽

Heat Removal ◽

Element Model ◽

Large Area ◽

Degradation Rates ◽

Sintered Silver

In automotive power electronics packages, conventional thermal interface materials such as greases, gels, and phase-change materials pose bottlenecks to heat removal and are also associated with reliability concerns. The industry trend is toward high thermal performance bonded interfaces for large-area attachments. However, because of coefficient of thermal expansion mismatches between materials/layers and resultant thermomechanical stresses, adhesive and cohesive fractures could occur, posing a reliability problem. These defects manifest themselves in increased thermal resistance. This research aims to investigate and improve the thermal performance and reliability of sintered-silver for power electronics packaging applications. This has been experimentally accomplished by the synthesis of large-area bonded interfaces between metalized substrates and copper base plates that have subsequently been subjected to thermal cycles. A finite element model of crack initiation and propagation in these bonded interfaces will allow for the interpretation of degradation rates by a crack-velocity (V)-stress intensity factor (K) analysis. A description of the experiment and the modeling approach are discussed.

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