•PCMs integrated building envelope and equipment in 2004∼2017 are reviewed.•Melting temperature range of PCMs used for envelope is 10∼39°C.•Melting temperature range of PCMs used for equipment is ...−15.4∼77°C.•PCMs’ positive effects on energy saving and thermal comfort are demonstrated.•The existing gaps in the research works are identified and classified as 5 aspects.
Confronted with the crises of the growing resource shortages and continued deterioration of the environment, building energy performance improvement using phase change materials has received much attention in recent years. This review work provides an update on recent developments, 2004∼2017, in phase change materials used to optimize building envelope and equipment. Firstly, a review of building envelope optimization methods by integrating surrounding wall, roof, and floor with phase change materials, is given. This is followed by reporting articles on building equipment optimized with phase change materials to reduce regular energy consumption. Series of air cooling, heating, and ventilation systems coupled with thermal energy storage were comparatively investigated. Finally, the existing gaps in the research works on energy performance improvement with phase change materials were identified, and recommendations offered as authors’ viewpoints in 5 aspects. It was also found that the phase change temperature range of PCMs used was changed from 10∼39°C for envelope to −15.4∼77°C for equipment. We believe this comprehensive review might provide an overview of the analytical tools for scholars, engineers, developers, and policy designers, and shed new light on the designing and performance optimization for PCMs used in building envelope and equipment.
•This study presents a detailed review on IRT for the investigation of building envelope defects.•The literature survey is conducted regarding existing IRT methodologies for building envelopes.•The ...previous studies with measurement methods, analysis schemes and analysis types are categorized in the literature matrix.•Recent advances and future trends on IRT methods are presented.
Thermal radiation generated by limited resources is emitted from the surfaces and interpreted as temperature. On the other hand, the limited resources necessitate prevention of energy leakages causing noticeable temperature differences on surfaces. Providing sensitive information on temperature contrast, infrared thermography (IRT) is a prominent tool for detecting infrared energy on the surfaces of the objects. IRT is also very promising method for detecting thermal irregularities, air leakages and even moisture abnormalities on building envelopes. Since the concept of nearly zero energy buildings is to be the main target of energy policies in European Union published by European Commission, improving thermal performance of buildings becomes crucial in the last decade. Therefore, implementation of IRT for visualizing and analyzing concealed defects on building envelopes is very promising for improving the energy efficiency of buildings.
Given recent regulations and benefits of emerging thermogram technologies mentioned above, a detailed review of the previous studies investigating the abnormalities of building envelopes by IRT is presented in this paper. Furthermore, the applications with measurement methods, analysis schemes and analysis types are classified to highlight the potential of IRT in inspection of building envelopes for providing energy efficient solutions. Finally, recent advances and practical future opportunities are presented for additional contribution of the IRT methods previously employed.
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•LCCA formulation considering different BIPV EOL material recovery and societal benefits.•Investigation of the impact of EOL material recovery approaches on the LCCA of BIPV.•A ...methodology to calculate rationale subsidy is presented.•BIPV system performance has been evaluated after four years of operation.•BIPV system as a building envelope material in Norway is economically feasible.
In dense urban areas, the use of building integrated photovoltaics (BIPV) façades are becoming popular and they are bringing many advantageous along with the energy-saving features. However, at the same time, they raise tensions in capital investments and overall returns. “Solsmaragden” is one of such a commercial building, that is integrated with BIPV façade with the peak power of 127.5 kW and owned by Union eiendomsutvikling AS in Norway. In this paper, a lifecycle cost analysis (LCCA) of BIPV façade integrated to “Solsmaragden” is investigated based on on-field recorded data after four years of operation (2016–2019). While formulating LCCA, numerous benefits from system power generation, societal and environmental benefits, and financial gains due to three different end-of-life material recovery approaches were also considered. The result based on the field monitored performance showed that the net present value (NPV), discounted payback period, internal rate of return and levelised cost of energy of the system is equal to 478,934 NOK, 22 years, 6% and 1.28 NOK/kWh, respectively. It is observed that the BIPV system as a building envelope material for different orientations of the building skin could reimburse not only all the investment costs but also become a source of income for the buildings. The results also illustrated that the granted subsidy is substantially covering the societal and environmental benefits of this project.
•Switchable insulation is an effective means of regulating heat through envelopes.•Current research on switchable insulation is fragmented across multiple domains.•We review existing technologies ...systematically and propose a classification system.•We assess their performance and improvement opportunities for building applications.
Switchable thermal insulation, in the form of an opaque panel that alternates between thermally conductive and insulated states, can be an effective means of regulating the thermal environment by selectively transferring heat between the indoor and outdoor environments. Pioneering work has been undertaken by researchers to develop switchable insulation technologies intended for applications in the built environment, automotive, and aerospace, where conventional space heating and cooling technologies are either too bulky or too energy consuming to meet design requirements. Switchable insulation technologies are in their infancy and the emerging research on this topic is unstructured and fragmented across disparate application sectors and very few of the adaptive insulation concepts and technologies are actively being pursued by the buildings research community. The aim of this paper is therefore to advance the understanding of switchable insulation for possible applications in the building envelope, by reviewing and classifying the existing technologies systematically, with a particular focus on their working principles, theoretical performance and improvement opportunities. The paper provides a qualitative and quantitative assessment of the most promising switchable insulation technologies for building envelopes and identifies the opportunities for further research in each of the technologies.
An extensive study, including energy and economic analyses has been proposed to assess the benefits of the phase change materials (PCMs) when integrated into building envelopes under the Tunisian ...climate. Sensitivity analyses have been presented in order to investigate the PCM interaction with the thermal insulation and the cool roof measures. Numerical simulations with EnergyPlus highlighted the crucial selection of an optimal phase change temperature. The PCM applied on the outside face of a brick wall provided better energy efficiency, with the highest energy savings up to 13.4% achieved for the south orientation. The integration of the PCM improved the thermal inertia of the wall with an increase of 2 h in the time lag for the east orientation. A 30-year life cycle cost analysis showed that the integration of the PCM in a brick wall is not cost-effective. The interaction between the PCM and the thermal insulation in a brick wall showed a better efficiency of the PCM in the absence of insulation, providing the highest rate of energy consumption reduction, estimated to 12.21%. The integration of the PCM in a concrete-based cool roof compensated the wintertime penalties and reduced the daily surface temperature fluctuation by up to 5.35 °C.
•Proper application of PCM can provide annual energy savings in Mediterranean climate.•Extensive LCCA is performed and the sensitivity to economical indicators is examined.•The PCM layer shows a better efficiency when integrated in an uninsulated wall.•Combination of PCM with cool roofs attenuates the thermal stress on the cool coating.•The proposed methodology applies to other climates and envelope component structures.
Whole building energy modeling has become extremely important for designers, architects, engineers, and researchers to predict energy performance of buildings. This is particularly important for ...phase change materials (PCMs) due to their variable properties. For this reason, building energy modeling tools have been developed and validated against different sources of experimental data. However, an IEA Annex 23 surveyed over 250 research publications concluding that the general confidence in currently used numerical models is still too low to use them for designing and code purposes. The objective of this study is to assess the capability of different simulation programs to model the PCMs in building envelope using data from two independent studies using Nano-encapsulated PCMs (Nano-PCM) and shape-stabilized PCMs. The study finds that the investigated PCM models accurately predict the PCM behavior in the building envelope.
•Validation study considered 6 PCM models in 5 software packages.•Two independent experimental studies provide the data.•Studies use Nano-PCM embedded in drywall and shape-stabilized PCM behind drywall.•Comparison of the modeled results demonstrate their ability to accurately model PCMs.
Building form and envelope surfaces play a significant role in energy performance assessment and the generated energy potential of the building integrated photovoltaics (BIPV) concept in early-stage ...design. To increase the energy efficiency level, form factor (FF) is proposed as a helpful tool that provides a strong relationship between the exposed surface areas and the treated floor area (TFA).
This research aims to develop a methodology for a parametric study to determine the related balance between the TFA and the required BIPV area in the form enclosure to meet specific primary energy demand (SPED) according to the international Passive House standard (PHS). Therefore, various form types, including square, rectangle, L, and T shapes, derived from four modular cubes, are classified based on the same FF. Optimal form selection per group is conducted through BIPV potential evaluation for the exposed surfaces in six different orientations separately. Thereafter, the BIPV efficiency level for the optimized forms is examined using its utilization factor and coverage index scenarios based on the façade and roof combination priorities. The results indicate that the generated energy sufficiency is affected by the form configuration and its orientation. Additionally, the optimal BIPV-based FF value of 0.71 implies the priority of roof-based scenarios for less BIPV utilization. Finally, the correlation value for the BIPV coverage index relative to the total envelope for the optimal forms and orientation is higher than 0.92, which can be extended to other forms in different locations as an assessment model.
•BIPV energy performance of various form types is analyzed based on the same Form Factor.•Enough distance is applied for detached forms to avoid the shading effect.•Specific primary energy demand is according to the Passive House Standard (PHS).•BIPV Form Factor plays significant role in BIPV performance determination.•High R2 value of BIPV Coverage Index confirms the high reliability of TFA and FF tools.
•Determine ideal variable thermo-physical properties of building envelopes.•Select and develop variable thermo-physical property materials.•Measure variable thermo-physical properties.•Apply variable ...thermo-physical property building envelopes.
Buildings consumed about 30% of total commercial energy and emitted 28% of the CO2 in the world in 2018. A new and effective approach to reduce the energy consumption and CO2 emission is to develop building envelopes with variable thermo-physical property materials such as phase change materials (PCMs) and/or smart glazing material, so as to make full use of climate resources including solar energy and ambient air temperature variation. However, how do we determine the ideal variable thermo-physical properties of those kinds of building envelope materials? How do we prepare or select the corresponding material accordingly? How do we measure such variable thermo-physical properties in a convenient and economical way? How do we design and apply these building envelopes suitably and effectively? This paper reviews literature studies to answer these questions. The main thread of the review is: (1) to determine the ideal thermo-physical property materials for opaque or transparent building envelopes by an inverse problem-variation solution method; (2) to evaluate methods of selecting or developing practical building envelope materials, especially PCMs, with variable thermo-physical properties accordingly; (3) to compare the DSC, T-history and T-depth methods of measuring thermo-physical properties of opaque building envelope materials; (4) to describe applications of various opaque and transparent variable thermo-physical property building envelopes and heating, ventilating and air-conditioning (HVAC) systems. This review shows that the ideal thermo-physical properties of building envelope materials can best be obtained with the inverse problem-variation solution method. Based on that, variable thermo-physical property materials, including phase change materials, thermochromic /electrochromic/ photochromic smart glazing and heat pipe, can be selected and prepared. Optimal building climate response performance and energy-saving can be achieved by using variable thermo-physical building envelopes. Finally, some problems worthy of future research are presented.
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Built environments contribute significantly to mitigating climate change. However, existing buildings, which form most urban infrastructures, do not typically meet contemporary ...stringent energy efficiency standards. They are naturally continuously deteriorating, making them a continuous negative contributor to their surrounding environments, which keeps getting worse. Therefore, there is a need to develop performance diagnosis frameworks and approaches for accurate Building Energy Model (BEM) simulations to develop impactful retrofitting design solutions that could make existing buildings perform closer to current efficiency measures. This paper reports on research that focuses explicitly on calibrating envelopes of existing BEMs using drones equipped with thermography sensors. The study specifically focuses on the automation of on-the-fly envelope U-value estimations and verification of calibrated envelope BEMs. The paper examines a renovated campus building in Boston, MA., representing material degradation, thermal bridging, and insulation failures using thermal imaging. A BEM is then calibrated, and post-renovation metered and modeled wintertime heating energy are compared. Goodness of fit measures showcase BEM performance improvement from 21.8%to 0.9%, which demonstrates the utility of the proposed framework. Further research is recommended to expand the focus on anomalies in the envelope and increase the scope from the building scale to the neighborhood scale.
This paper deals about the response of envelope to various climatic conditions and it is the main reason to know the amount of energy needed to maintain thermal comfort of the inner environment. The ...building envelope reduces external stress especially in hot climates and it was determined by subjecting its individual orientations and composition. The study is to reconstruct the envelope parts by changing wall material, thermal insulation materials in wall pattern and minimize its U-value to reduce the heat the heat transfer and determine it by using AUTOCAD and FOURLY ANALYSIS PROGRAM of ASHRAE 2013 standard.
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