Case study on the optimal thickness of phase change material incorporated composite roof under hot climate conditions (original) (raw)
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Thermal Science, 2021
Integration of phase change material (PCM) in walls and roof of a building is done to augment human comfort at places where variation of local diurnal temperature of ambient air is extensive. An exhaustive tool to study on year-round thermal effect due to solar radiation falling on a building is generally required to identify the correct PCM and the portion of a year that warrants better thermal management. The transient behavior associated with PCM heat transfer through building roof and walls vary in accordance with location and orientation of the building and the prevailing seasons. Hence, it becomes necessary to carry out a detailed analysis with the integration of PCM layers and to collect information with suitable theoretical approach as experimental study on energy performance of a building is time-consuming and expensive. In this paper, a three-dimensional building model has been developed and analyzed using ANSYS FLUENT for performing CFD analysis for comparing two identica...
A Review of PCM's Thermal Performance Within Lightweight Construction
Generally, buildings with lightweight construction tend to have large temperature fluctuations due to external temperature loading (cooling/warming), solar heat or internal loadings of the building (appliances/equipment). The incorporation of Phase Change Material (PCM) in lightweight building walls can decrease the temperature fluctuations of the building, particularly external solar radiation loads. This research paper provided a review of related literature on reducing energy consumption for heating and cooling purposes. The findings of the research gave suggestions on the most effective method of incorporating PCM in order to provide thermal protection/thermal benefits for lightweight construction techniques.
Sustainable Energy Technologies and Assessments, 2021
This paper experimentally investigates the optimal position of a phase change material (PCM) incorporated composite roof under Iraq climatic conditions. The roof composed of Isogam (4 mm), concrete (50 mm) and gypsum board (8 mm) which is an Iraqi popular roof combination. Four models are installed and tested; one represented the reference roof (Model A) and the others incorporated with PCM. The PCM placed between Isogam and concrete (Model B), in the middle of concrete (Model C), and between the concrete and gypsum board (Model D). Set of indicators are introduced to compare among models considering the test room temperature , outside and inside roof surface temperatures. These indicators are the room maximum temperature reduction (RMTR), average temperature fluctuation reduction (ATFR), decrement factor (DF), time lag (TL) and heat flux reduction (HFR). Results showed that Model B verified the best thermal performance, and the PCM was effectively working at high outside temperatures. The maximum room temperature of PCM models was reduced by up to 9 • C compared with the reference model. Moreover, a maximum of 12.9%, 8.4-9.5 • C, 0.44-0.49, 140-180 min, 47.9-64.6% of respectively RMTR, ATFR, DF, TL, and HFR, are obtained for Model B under high outside temperatures. Introduction Buildings and constructions are responsible for more than 36% of global final energy end-use and 39% of CO 2 emissions due to rapid population and urbanisation [1]. Therefore, serious improvements towards sustainable buildings are required to meet the Paris Agreement's target by improving buildings' energy intensity by up to 30% by 2030 compared with 2015 [2]. Amongst recent technologies, building envelope based PCM is a booming technology nowadays that showed remarkable benefits concerning building energy efficiency through improving the building thermal comfort and energy saving [3-6]. Despite the remarkable advances of PCMs to improve the thermal performance of any envelope element integrated with, there are still open questions regarding key parameters for their efficient use, such as PCM's influential position. PCM's best position within the building envelope plays a predominant role in controlling the PCM performance, which depends highly on the PCM thermal properties and environmental conditions [7]. In other words, specifying PCM's optimal position within the building envelope is a key factor of the technology. It affects the rate and time to reach the full exploitation of PCM potential, influencing the building's energy performance accordingly [8]. Researchers have made efforts to point out the PCM layer's optimal position under different climatic conditions, but no universal agreement has been reached. Under hot locations, studies were chiefly concluded three influential positions, namely close to the envelope exterior, middle of the envelope and, close to the indoor environment. Lagou et al. [9] numerically investigated PCM's optimal position integrated non-conditioned buildings in diverse European countries at different locations. Analytical results revealed that the PCM should be placed in the interior edge to get the best PCM performance for all locations, including the hot ones. Hu and Yu [10] numerically studied the optimal position concerning the insulation in roof combination in five cities of China. Under summer conditions, the results showed that the optimal PCM position is to the inside of insulation where the cooling loads were decreased remarkably. The reason attributed to that the heat transferred
Effect of PCM in improving the thermal cooling comfort in buildings ceiling
2019
The demand for energy increases around Australia because of the massive growth in population and industrial sector, which lead to Increase energy supply. A result of this growth, Increase in the consumption of fossil fuel and that produce more CO2 emission. Many scientist and engineers claimed. Phase change material (PCM) considered a great option in the residential building to save energy and thermal comfort. From this concept, the thesis purposes are to analyse and investigate PCM performance in passive cooling in the residential ceiling by modelling, and experiment methods whether PCM will save cost and reduce CO2 emission. The method was divided into two parts the first one in modelling and the second part is experimenting. The first part was by modelling the PCM with other types of insulations in the ceiling with the consideration of weather data history around Murdoch University location and the measurement of the whole ceiling design. OPAQUE 3.0 beta software has been used to...
Applied Energy, 2022
Phase change materials (PCMs) can beneficially work as a successful thermal energy storage medium in different applications. PCMs have shown a remarkable enhancement in building energy-saving and thermal comfort in hot locations. In this paper, the thermal behaviour of a PCM-enhanced thermally-poor building envelope is studied experimentally. To this aim, two identical rooms, one loaded with PCM (PCM room) and the other without (reference room), are built and tested under a severe hot climate of Al Amarah city, Iraq. Previously examined parameters, such as the optimal position and thickness of the PCM layer in the roof and the best-thermally performed PCM capsules integrated concrete bricks, are considered to build the PCM room. Several energetic and thermal comfort indicators such as maximum temperature reduction (MTR), average temperature fluctuation reduction (ATFR), decrement factor (DF), time lag (TL), operative temperature difference (OTD), discomfort hours reduction (DHR) and maximum heat gain reduction (MHGR) are determined and discussed to show the potential of PCM. The experimental results revealed that the incorporated PCM could remarkably improve the thermal performance of building envelope exposed to high outdoor temperatures. Amongst envelope elements and compared with the reference room, the roof and east wall of the PCM room recorded the best thermal behaviour, where the MTR difference, ATFR, DF, and TL difference reached 3.75 °C, 6.5 °C, 25.6%, 70 min for the roof, and 2.75 °C, 2.4 °C, 12.8% and 40 min for the east wall, respectively. Moreover, the PCM room shows a thermal comfort enhancement by 11.2% and 34.8%, considering the DHR and MHGR, respectively, compared with the reference one. The study highlighted that suitable ventilation means are necessary to improve the building performance and reach acceptable thermal comfort when the PCM is incorporated passively.
PCMs in building envelope characteristics, applications, key parameters and energy contribution
Mechanical Engineering Letters, Szent István University, 2021
The present paper discusses the main aspects of incorporation phase change materials (PCMs) for building envelope applications. A brief overview of PCM types, properties and desired characteristics for building applications are presented. Besides, the possible incorporation applications in practice are discussed for several building envelope elements and construction materials. The key parameters that affect the thermal performance of PCMs in building applications are presented and discussed. Finally, some state-of-the-art studies reported in the literature are investigated and analysed to highlight the contribution to building efficiency gained by PCMs. It has been shown that PCMs plays an essential role in building envelope and can improve its thermal efficiency significantly. However, more investigations regarding this technology still need to be maintained as presented in the conclusions.
Renewable Energy, 2015
This paper presents a new hybrid methodology for the determination of the effective heat capacity (Ceff) of phase change materials (PCMs) for use in numerical models. The methodology focuses on PCM enhanced building panels utilizing a heat flow meter apparatus (HFMA) operating in dynamic mode and a numerical model based on the effective heat capacity method. It comprises of: a) experimental analysis of the panel by means of differential scanning calorimetry (DSC) and HFMA for the estimation of initial Ceff curves, b) optimization of the initial Ceff curves with an algorithm incorporating the numerical model and c) validation of the obtained results. Starting from a complete description of the concept and its main elements, the proposed approach has been successfully employed for the determination of Ceff curves of a lightweight building component combining insulation with thermal storage properties. The derived curves yielded more accurate results when incorporated in the numerical model than the respective curves measured by means of DSC. Simulations of the thermal performance of the building component in different conditions than those used for the determination of the curves validated the effectiveness of the methodology.
Energies
Thermal energy storage integration using phase change materials (PCMs) in buildings has great potential for energy conservation and greenhouse gas (GHG) emission reduction. Cutting-edge research and innovative ideas are required when using multilayered PCMs within typical construction materials to take advantage of their heat storage capability over a wide temperature range within buildings. This current study was carried out to experimentally test the efficacy of using dual PCMs RT28HC and RT21HC with different melting temperature ranges (28 °C and 21 °C) under variable thermal loading. The transient thermal response of various PCM-based configurations of concrete and cement blocks at different temperature inputs was obtained to determine the effectiveness of dual PCMs and their optimized configuration under experimental laboratory conditions. The range of the temperature input was varied from 22 °C to 50 °C, suitable for hot climatic conditions such as those in Pakistan. Laborator...