Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection

Permanent URI for this collectionhttps://hdl.handle.net/11147/7148

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Access Right: Open AccessSubject: search.filters.subject.Phase change materials

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  • Article
    Citation - WoS: 120
    Citation - Scopus: 136
    Numerical Study on Latent Thermal Energy Storage Systems With Aluminum Foam in Local Thermal Equilibrium
    (Elsevier, 2019) Buonomo, Bernardo; Çelik, Hasan; Ercole, Davide; Manca, Oronzio; Mobedi, Moghtada
    The paper analyzes the behavior of a Latent Heat Thermal Energy Storage system (LHTES) with a Phase Change Material (PCM), with and without aluminum foam. A numerical investigation in a two-dimensional domain is accomplished to investigate on the system thermal evolution. The enthalpy-porosity method is used to describe the PCM melting. The open-celled aluminum foam is described as a porous medium by means of the Darcy-Forchheimer law. A hollow cylinder represents the considered thermal energy storage and it consists of the enclosure between two concentric shell tubes. The external surface of the internal tube is at assigned temperature with a value greater than the melting PCM temperature, while the other surfaces are adiabatic. Local thermal equilibrium (LTE) is numerically adopted for modelling the heat transfer between the PCM and the solid matrix in aluminum foam. In the case with metal foam, simulations for different porosities are performed. A comparison in term of liquid fraction, average temperature of the system, temperature fields, stream function and a performance parameter are made between the clean case and porous assisted case for the different porosities. A scale analysis is developed for evaluating the time and the melting zone in different regimes (i.e. conduction, mixed conduction-convective and convective) during the melting processes of the PCM in porous media. Numerical simulation shows that aluminum foam increases overall heat transfer by a magnitude of two, with respect to the clean case.
  • Article
    Citation - WoS: 12
    Citation - Scopus: 12
    An Evaluation Methodology Proposal for Building Envelopes Containing Phase Change Materials: the Case of a Flat Roof in Turkey’s Climate Zones
    (Taylor and Francis Ltd., 2017) Tokuç, Ayça; Yesügey, Sadık Cengiz; Başaran, Tahsin
    Phase change materials (PCMs) can be used to enhance the thermal energy storage capacity of a building element to improve indoor thermal comfort conditions and decrease energy usage, yet these effects need to be carefully analysed to achieve the desired benefits. This paper proposes an evaluation methodology for building envelopes: first, a numerical computational fluid dynamics model is validated by experimental work; then, time-dependent simulations are used to analyse monthly energy requirements and heat flux. A sample flat roof is evaluated in terms of required cooling load with and without PCM in Turkey’s climate zones. Graphical phase change representations and heat flux results were used to evaluate the cooling load reduction in addition to the effects of PCM type and PCM amount and the necessity for night cooling. In conclusion, the methodology is flexible and can be utilized to evaluate the building element for various parameters.
  • Article
    Citation - WoS: 54
    Citation - Scopus: 63
    An Experimental and Numerical Investigation on the Use of Phase Change Materials in Building Elements: the Case of a Flat Roof in Istanbul
    (Elsevier Ltd., 2015) Tokuç, Ayça; Başaran, Tahsin; Yesügey, Sadık Cengiz
    This paper reports on the experimental and numerical analysis of a building element-a flat roof-that incorporates phase change material (PCM) as a layer. First, a planar model of the building element of 50 cm by 50 cm surface area was constructed in laboratory conditions to be used in the experimental work. During the experiment, changes in the thermal balance were investigated by temperature and volumetric flow rate measurements, as well as observation of the phase change interface. Next, the experimental measurements were used to validate a numerical computer fluid dynamics (CFD) model for simulation purposes. The model is one-dimensional and is based on the first law of thermodynamics. Finally, a time-dependent simulation for summer conditions was performed using the climatic data of Istanbul. The thickness of the PCM inside the roof element was investigated accordingly. The simulation data showed the solid/liquid phase of PCM over time. Monthly graphs were drawn for ease of comparison of the use of PCM with thicknesses varying between 1 and 5 cm. Consequently, a PCM thickness of 2 cm was found to be suitable for use in flat roofs in Istanbul.