Low Emissivity Materials Research Articles

Anodization-Processed Colored Radiative Thermoregulatory Film.

Colored radiative thermal management materials (RTMM) not only provide superior thermoregulatory performance but also satisfy aesthetic requirements. However, the complexity of the preparation procedures and constrained color selection have hindered their widespread adoption. Here, we presented a facile one-step anodizing strategy for fabricating colored dual-mode RTMM based on titanium film (Ti) and P(VDF-HFP) with mid-infrared (MIR) emissivities of 0.07 and 0.96, respectively, which allow for on-demand temperature modulation (rise of 28.2 K and drop of 9 K) without energy consumption. Furthermore, demonstrations of a colored radiative warming membrane also validate the effectiveness of anodizing treatment. The colored Ti/nano PE membrane with 10.8 μm thickness enables a temperature rise of 2.3 K on real human skin, which is much higher than that of commercial fabric with 120 μm thickness (0.7 K). This strategy provides insights for the scalable fabrication and application of colored low emissivity materials, contributing to the goal of a sustainable society.

Sustainability assessment with the green retrofitting concept for building: A study case in the Gresik regency, Indonesia

In green construction, sustainable resources are essential. One such material is copper, which is widely utilized in electronics, transportation, manufacturing, and residential buildings. As a very useful material, it has many beneficial impacts on human life. Observed from the recent demand spike is in line with the overall trend and the current growing smelter construction in Indonesia. Researchers intend to adapt the existing Copper Smelting Plant Building into an environmentally friendly building as a part of the production chain, in addition to reducing public and environmental concerns about the consequences of this development. We have identified a disparity in cost, where the high cost of green buildings is an obstacle to its implementation to enhance the cost performance with increased renewable energy of the Smelter Construction Building, this study investigates the application of LEED parameters to evaluate green retrofit approaches through system dynamics. The most relevant features of the participant assessments were identified using the SEM-PLS approach, which is used to build and test statistical models of causal models. We have results for this Green Retrofitting study following significant variables according to the following guidelines: innovation, low-emission materials, renewable energy, daylighting, reducing indoor water usage, rainwater management, and access to quality transit.

The Impact of Green Building Design on Indoor Air Quality and Occupant Experience

This study examines the impact of green building design on indoor air quality (IAQ) and occupant experience, using Heritage Place in Ikoyi, Lagos, as a case study. Green buildings are known for incorporating sustainable practices such as the use of eco-friendly materials, advanced ventilation systems, and biophilic design elements, all aimed at enhancing environmental sustainability and occupant well-being. A descriptive survey methodology was employed, with data gathered through a questionnaire administered to 50 occupants of the building to assess their perceptions of IAQ, health, comfort, and overall satisfaction. The findings indicate that the majority of respondents reported high levels of satisfaction with IAQ, attributing improvements in their health, productivity, and comfort to the building’s green design features. Specifically, low-emission materials and enhanced ventilation systems were highly praised for reducing pollutants and maintaining a healthy indoor environment. However, a few respondents expressed concerns about inconsistent thermal comfort in certain areas. These results underscore the importance of sustainable design in creating healthier, more productive indoor environments. Recommendations for future green building projects include fine-tuning HVAC systems to improve thermal comfort and enhancing occupant education on the benefits of sustainable features.

Fabrication of Low-Emissivity Glass with Antibacterial Properties by Coating Cu/AZO Thin Films

This study explores the feasibility of using Cu/AZO thin films as low-emissivity materials with antibacterial properties, fabricated using the linear sputtering method. The linear sputtering technique deposits thin films onto continuous substrates, offering high throughput, uniform coatings, and precise control over film properties. In this research, Cu/AZO thin films underwent either vacuum annealing or hydrogen plasma annealing treatments. The Cu layer imparts antibacterial properties, while the AZO layer primarily provides thermal insulation. Experimental results show that annealing treatments enhance both photoelectric performance and antibacterial capability. Annealed Cu/AZO films exhibit lower resistivity and emissivity. Among the samples, those subjected to vacuum annealing at 400 °C are most suitable for low-emissivity applications, with an average visible light transmittance of 60%, an emissivity of 0.16, and an antibacterial activity value of 8.8. The Cu/AZO films proposed in this study effectively combine antibacterial and thermal insulation properties, making them relevant for the field of green materials.

Suočavanje s izazovima u vezi s ocjenjivanjem zelene gradnje prema LEED-u u Turskoj

This study examined the effectiveness of the LEED green building rating system and identified performance gaps in developing countries using Türkiye as a case study. The analysis of 134 LEED Platinum V4-certified buildings in Turkiye revealed discrepancies in high-priority sites, site evaluation, building product definition and optimisation, and low-emission material credits compared with other countries. Variations in energy, atmosphere, and indoor environmental quality criteria were also noted within LEED Platinum-certified buildings in Turkiye. The study concludes that while LEED is widely embraced, local standards and contextual factors must be considered when implementing these programs.

Influence of emissivity on infrared camouflage performance

The rapid development of infrared detection technology has generated an urgent demand for infrared camouflage, sparking widespread interest in low-emissivity materials. Novel material designs and advanced micro/nanofabrication technologies make it possible to realize materials with extremely low emissivity. However, a lower infrared emissivity does not always mean a better camouflage performance. There is a lack of sufficient discussion on how to determine an appropriate emissivity for a specific working condition to achieve effective infrared camouflage. Here, through outdoor experiments, we demonstrated that for a specific scenario, an appropriate emissivity always exists that can make the infrared characteristics of the target effectively blend into its background, and deviations from the emissivity result in deteriorated camouflage performance. Further, we established a heat transfer model to conduct quantitative analysis on the influence of emissivity on infrared camouflage performance in terms of surface temperature and radiative temperature in various conditions. In addition, we proposed a general method for determining the optimal emissivity of infrared camouflage, defined as the emissivity value at which the radiative temperatures of the target and the background are equal. To facilitate practical application of this method, we developed a user-friendly MATLAB app named “Optimal Emissivity Calculator” to calculate the optimal emissivity. It was found that for a vehicle’s engine compartment surface at approximately 340.0 K, the optimal emissivity is 0.4 with a background temperature of 300.0 K. This work highlights the significance of selecting appropriate emissivity for infrared camouflage and provides a reference for designing the emissivity of infrared camouflage materials.

Addressing challenges in LEED green building ratings in Türkiye

This study examined the effectiveness of the LEED green building rating system and identified performance gaps in developing countries using Türkiye as a case study. The analysis of 134 LEED Platinum V4-certified buildings in Turkiye revealed discrepancies in high-priority sites, site evaluation, building product definition and optimisation, and low-emission material credits compared with other countries. Variations in energy, atmosphere, and indoor environmental quality criteria were also noted within LEED Platinum-certified buildings in Turkiye. The study concludes that while LEED is widely embraced, local standards and contextual factors must be considered when implementing these programs.

Ultrawide Spectra Camouflage Coatings from Metallic Flake Powder.

Ultrawide-spectra-compatible camouflage materials are imperative for military science and national security due to the continuous advancement of various sophisticated multispectral detectors. However, ultrawide spectra camouflage still has challenges, as the spectral requirements for different bands are disparate and even conflicting. This work demonstrates an ultrawide spectra camouflage material compatible with visible (VIS, 400-800 nm), infrared (IR, 3-5 and 8-14 μm), and microwave (S-Ku bands, 2-12 GHz). The carbon nanotubes adsorbed on porous anodic alumina/aluminum flake powder (CNTs@PAA/AFP) material for ultrawide spectra camouflage is composed of bioinspired porous alumina surface layers for low visible reflection and aluminum flake powder substrate for low infrared emissivity, while the surface of the porous alumina layers is loaded with carbon nanotubes for microwave absorption. Compared with previous low-emissivity materials, CNTs@PAA/AFP has omnidirectional low reflectance (Ravg = 0.29) and high gray scale (72%) in the visible band. Further, it exhibits low emissivity (ε3-5μm = 0.15 and ε8-14μm = 0.18) in the dual infrared atmospheric window, which reduces the infrared lock-on range by 59.6%/49.8% in the mid/far-infrared band at high temperatures (573 K). The infrared camouflage performance calculated from the radiation temperature of CNTs@PAA/AFP coatings is enhanced to over 65%, which is at least 4 times greater than that of its substrate. In addition, the CNTs@PAA/AFP coating achieves high microwave absorption (RLmin = -42.46 dB) and an effective absorption bandwidth (EAB = 7.43 GHz) in the microwave band (S-Ku bands) due to the enhancement of interfacial polarization and conductive losses. This study may introduce new insight and feasible methods for multispectral manipulation, electromagnetic signal processing, and thermal management via bioinspired structural design and fabrication.

Leadership in Energy and Environmental Design Commercial Interior Version 4 (LEED-CI v4) Gold-Certified Office Space Projects: A Pairwise Comparative Analysis between Three Mediterranean Countries

Over the past five years, Leadership in Energy and Environmental Design Commercial Interior version 4 (LEED-CI v4)-certified office projects have been intensively studied in the USA and China, but they have not yet been studied in the Mediterranean region. The purpose of this study was to explore office building certification strategies for LEED-CI v4-certified projects in the Mediterranean region. The study design included pairwise comparative analyses between Spain (number of projects (n) n1 = 14), Türkiye (n2 = 13), and Israel (n3 = 11). Cliff’s δ and exact Wilcoxon–Mann–Whitney tests were used to process ordinal and discrete data, while the natural logarithm of the odds ratio and 2 × 2 Fisher’s exact tests were used to handle dichotomous data. It was found that Spain and Türkiye outperformed Israel in the Location and Transportation (LT) category due to their desire to reduce the use of private transport. Spain and Türkiye were ahead of Israel in the LTc5 “reduced parking footprint” credit (p = 0.008 and 0.0005, respectively). Israel outperformed Spain and Türkiye in the Energy and Atmosphere (EA) category due to the sum of all six EA credits (p = 0.086 and 0.010). Spain overtook Türkiye and Israel in the Materials and Resources (MRs) category due to Spain’s increased use of environmental product declarations. Spain and Türkiye were ahead of Israel in the following four MRs credits: MRc1 “long-term commitment” (p = 0.030), MRc2 “interiors life cycle impact reduction” (p = 0.037), MRc3 “building product disclosure and optimization—environmental product declarations” (p = 0.029), and MRc5 “building product disclosure and optimization—material ingredients” (p = 0.034). Spain, Türkiye, and Israel showed similarly low levels of achievement in the Indoor Environmental Quality (EQ) category (p ≥ 0.405). However, Spain and Türkiye outperformed Israel in the following two credits: EQc1 “enhanced indoor air quality strategies” and EQc2 “low-emitting materials” (p = 0.001 and 0.060, respectively). In parallel, Israel outperformed Türkiye in the EQc3 “construction indoor air quality management plan” (p = 0.026), and Israel outperformed Spain in the EQc8 “quality views” credit (p = 0.066). As a result, a pairwise comparison of the three Mediterranean countries showed that each country has a unique LEED certification strategy. Knowledge of the above green building strategies will be helpful for LEED professionals.

Multiresonant Selective Emitter with Enhanced Thermal Management for Infrared Camouflage.

Tailoring the optical properties of metamaterials is crucial for improving the performance of infrared (IR) applications. Generally, IR camouflage materials are required to have low IR-emission properties for the detected bands (3-5 and 8-12 μm), in which IR detection is accomplished. However, the heat residue by suppressed thermal radiation degrades the thermal dissipation capacity and thermal stability of IR camouflage materials. Herein, a multilayer metal-dielectric-metal (MDM) selective emitter with high IR-emission performance in the undetected band for thermal management and low IR-emission performance in the detected band for IR camouflage is introduced. Compared to a conventional selective emitter and a low-emission material (Au film), the multiresonance selective emitter exhibited 125 and 2910% increases in heat dissipation within the undetected band, respectively. In addition, the proposed camouflage material exhibited a substantial reduction in emissive energy within the detected bands of 3-5 and 8-12 μm, with reductions of 72 and 83%, respectively, compared to that of a high-emission surface. The effectiveness of our IR camouflage was demonstrated by IR camera measurements. When the surface temperature was 360 K, the radiance temperatures of the multilayer multipeak selective emitter were 314 and 309 K for the 3-5 and 8-12 μm bands, respectively. Thermal management experiments demonstrated the enhanced thermal stability of the multiresonance selective emitter, especially in conditions of low pressure and high heat flux, when compared to that of the low-emissivity film. This work provides a practical strategy to enhance the thermal emission of a selective emitter, expanding its potential beyond IR camouflage to various energy applications.

The Relationship between the Parameters That Characterize a Built Living Space and the Health Status of Its Inhabitants

Housing is an essential component of the living environment, and it has a substantial effect on physical and mental well-being. Multiple housing factors, including inadequate ventilation, overcrowding, construction materials, and exposure to allergens and pollutants, have been linked to a variety of diseases, such as respiratory ailments and dermatologic, rheumatologic, and cardiovascular disorders. The present narrative review shows the current state of knowledge in the field by centralizing and evaluating scientific publications with a focus on this linkage, detailing the implications for health status and the benefits of using natural materials in construction, implementing green building concepts, and applying technological transfer, where various decision factors can contribute to improving quality of life. Therefore, it is achievable to enhance the indoor air quality (IAQ) by promoting ventilation and air filtration, decreasing mold and moisture, and employing low-emitting materials in building construction and development. Overall, promoting healthy housing environments through an enhanced IAQ and using sustainable building practices can have a substantial positive effect on public health. To reduce the risk of housing-related diseases, future research should concentrate on identifying the most effective interventions to improve the living environment–health condition axis.

The Effect of Wooden Building Materials on the Indoor Air Quality of Houses

This work focuses on researching wood as a low-emitting building material. Many studies showed that by regulating the emission of adverse chemicals from pressed wood products, they could be recycled as low-emitting materials. The presented case study, shows the measurements of the indoor air quality in a passive, low-energy, wooden, light frame house. Concentrations of Volatile Organic Compounds (VOC) and formaldehyde were measured and compared with data from other case studies made in this subject and with the current Hungarian and international regulations of adverse chemicals. The main VOC materials which concentrations were significant in all measurements were terpenes (limonene, alpha-pinene, 3-carene), aliphatic-hydrocarbons and aldehydes (acetic acid, 2-Methoxy-1-ethylmethyl acetate). The comparison showed that the concentrations of benzene, toluene, naphthalene, formaldehyde, and styrene were not deviant from the average values measured by other case studies. The observations showed that the main influencing factors of indoor air quality were the changes in indoor temperature, relative humidity, air exchange rate, and human activities. The conclusion is that the wooden materials applied in the house are low-emitting materials and do not pose a health risk for people.

Life cycle analysis of timber roof structures

Construction industry is rapidly prospering. With numbers as high as they are in the construction industry, it is imperative to find alternative building materials and reduce waste. Proper combination and selection of materials helps to reduce the environmental burden on the surroundings. It is therefore appropriate to use local, natural, renewable, recyclable and low-emission materials in their production, which also helps to promote biodiversity and to restore and replace green spaces. In the fight against climate change, the construction industry is trying to reduce the emissions of buildings by means of life cycle assessment. The study assessed the life cycle of 55 wooden timber roofs in terms of their environmental impact. Based on the assessment of the timber roof compositions, it can be concluded that the best rating was achieved by the composition with structural construction timber, cellulose insulation, vented gap and aggregate backfill. When using wood fibre and cellulose insulation, a 65% reduction in global warming emissions is achieved.

Achieving the low emissivity of graphene oxide based film for micron-level electromagnetic waves stealth application

In recent years, the development of advanced materials with enhanced micron-level electromagnetic waves stealth properties has garnered significant attention due to their applications in fields such as military technology and thermal insulation. This study primarily investigates the stealth characteristics of materials within the 8–14 μm electromagnetic wave band, commonly known as the infrared (IR) spectrum. The effect of metallic Ag nanoparticles on the graphene oxide (GO) was obtained to achieve the excellent IR stealth ability. Specifically, Ag/GO composite films were prepared using a one-step reduction method and vacuum-assisted drying. The IR emissivity (8–14 μm) of the composites was significantly reduced with increasing Ag content, and the electrical conductivity of the materials was enhanced. When the Ag/GO mass ratio in the material was 1:2, the IR emissivity of the material at 8–14 μm was as low as 0.279, which was 62 % lower compared to GO. In addition, IR thermograms of the composites were analyzed using an IR thermographic camera. Obviously, the composites exhibited significant IR stealth properties when compared with those of GO. Thus, this work provides a reference for the preparation of carbon-based low IR emissivity materials for infrared stealth application.

Study on energy-saving potential of lowering the emissivity of unheated surfaces for floor radiant heating

It has been demonstrated that the application of low emissivity materials to unheated surfaces improves the thermal comfort level of radiant heating. However, it remains unclear whether the emissivity of unheated surfaces can shorten the response time of floor radiant heating (FRH) and whether there is energy-saving potential. Numerical simulations were conducted to determine the influence of unheated surface emissivity and wall insulation methods on the dynamic performance of FRH during intermittent operation. The results indicate that decreasing the emissivity of the unheated surface can effectively shorten the response time of FRH by 26.8 %, but at the expense of an increased start-up load. The difference between start-up load and steady heating load is between 1.8 and 2.3 times, which increases with the area of the internal insulating wall. Two energy-saving measures exhibit a "substitution" relationship that must be combined with an economic analysis to determine a reasonable implementation scheme, with the roof occupying a key position. This study provides an alternative energy-saving solution for heating and air conditioning in the hot summer and cold winter zone of China, as well as a design foundation for the promotion and application of FRH.

Enhancement of infrared stealth performance of ultra-high molecular weight polyethylene-based composites through the multilayer structural construction

According to the infrared stealth mechanism, combining the low emissivity material and temperature control material is an effective way to improve the infrared stealth performance. In this paper, ultra-high molecular weight polyethylene (UHMWPE)-based multilayer composites with low emissivity and thermal conductivity are prepared through the combination of the low emissivity layers and the thermal insulation layers. The infrared stealth performance of the composites is varied by changing the layer numbers and the thickness of the functional layers as well as the structural design. And the orientation of the low emissivity fillers is realized to further reduce the emissivity of the low emissivity layers. The infrared emissivity of the low emissivity layer is as low as 0.297 and 0.247 at 3–5 μm and 8–14 μm, respectively, which is 25.9% and 46.4% lower than that before modification. The surface temperature of the multilayer sample reaches 26.8 °C after being placed on a 60 °C hot stage for 30 min, exhibiting excellent infrared stealth performance. Meanwhile, the density of the sample is 0.48 g/cm3, and the thickness is 2.8 mm, which is permissible for the infrared stealth applications.

Environmental impact assessment of on-site and off-site construction logistics activities – A case study analysis from Norway

Construction site activities are one of the main contributors to GHG emissions in the construction industry. There are several on-going initiatives on finding low and zero emission solutions for reducing GHG emission from construction sites. The objective of this paper is to investigate the emission reduction potential from fossil and emission free on-site and off-site construction logistic activities based on actual data collected from a case study from Oslo. The paper firstly presents definitions and step wise approach for fossil free and emission free construction site activities. Then, GHG emission calculation from the logistic activities using LCA methods and scenario analysis to evaluate the environmental performance of fossil and emission free solutions considered in the selected case study. The results illustrated the GHG emission reduction potential from electrification of construction machineries and transport of material, collaboration between construction site for more efficient use and reuse of excavated masses, modal shift for transport of materials as well as the importance of clear description of the system boundary and background data. Availability of electric machinery, electrified means of transport and sufficient electricity supply, lack of requirements for low-emission material transport solutions, lack of data for LCA studies are identified as some challenges. Moreover, the study highlighted the potential contribution of increased demand for emission free solutions through public procurement to facilitate a change in the industry by overcoming these barriers.

Post Occupancy Evaluation of Indoor Air Quality in Green Rated Commercial Interiors

Good indoor air quality is crucial for the health, happiness, and satisfaction of the occupants. Since we spend so much time indoors, it is essential to maintain a reasonable level of indoor air quality. One of the elements contributing to the decline in indoor air quality was the interior materials. Having acknowledged this, green building rating systems have incorporated the use of low-emitting materials as a credit that may be gained. A system for assessing commercial interiors with a focus on interior materials exists and has been used by several commercial offices. This study aimed to understand the indoor air quality in green-rated commercial interior spaces that have won points for the use of low-emitting materials and indoor air quality. A post-occupancy review was conducted on an IGBC rated green commercial interior office space, in which various pollutant concentrations were measured and observations were made regarding space usage, cleaning processes, and maintenance. Almost 41.9% of the areas that were studied had CO2 values that exceeded the threshold. Additionally, the concentration of PM 2.5 was elevated in all locations, particularly during partial occupancy. The findings indicate that the use of low-emitting materials and finishes in office interiors helped to reduce the concentration of pollutants in the indoor environment. However, the concentrations of these various pollutants also depended on several other factors, such as the ventilation system, the use of electronic equipment, the frequency of cleaning practises, etc.

Critical assessment and demonstration of high-emissivity coatings for improved infrared signal quality for Taylor–Quinney coefficient experimentation

Over the infrared (IR) spectrum metals have relatively low emissivity. Considering that modern studies focused on determining the Taylor–Quinney coefficient rely on IR-based measurements to quantify temperature rise, there is a need to improve measurement certainty. This is of particular concern during the earliest stages of deformation when small temperature rises result in a low IR-signal to noise ratio. Herein an economical approach to improving signal quality is presented based on the deposition of a thin high emissivity coating on the material substrate (i.e., specimen) of interest. Coating material and coating thickness selection are founded on both heat transfer and electromagnetic performance. A maximum allowable thickness of 1μm was determined for the coating to ensure the recorded temperature of the coating closely matches the temperature of the deforming substrate (i.e., specimen) during the sub-millisecond duration of a split-Hopkinson (or Kolsky) pressure bar experiment. Using the transfer matrix method, the spectral emissivity of coatings made from commonly available metallic deposition sources with increasing thicknesses was calculated. Theoretical predictions identified a 250 nm thick Ti coating as a promising candidate for increasing surface emissivity without the coating acting as a thermal barrier. Confirmation of the coating layer’s ability to substantially improve IR signal amplitudes was examined experimentally for two low emissivity materials, specifically OFHC copper (Cu) and Magnesium (Mg) alloy AZ31B. IR detector calibration experiments showed a four to six times improvement in signal amplitude compared to native Cu and Mg surfaces. Additionally, the calibration curves of coated specimens converge exhibiting the same behavior allowing for a unified calibration curve to be used regardless of substrate material. Split-Hopkinson pressure bar experiments supported by IR thermography were conducted on coated specimens and Taylor–Quinney coefficients are reported. Taylor–Quinney coefficients obtained, are compared to literature values when appropriate, and show positive agreement to previously reported values. Real-time high-speed imaging and post-mortem analysis showed robust adhesion between the substrate to the thin Ti layer up to 16% strain.

Life-Cycle Assessment of LEED-CI v4 Projects in Shanghai, China: A Case Study

The purpose of this study was to explore green office building certification strategies in Shanghai. The 45 LEED-CI v4 gold-certified office space projects were sorted by energy and atmosphere credit (EAc6, optimize energy performance) into two groups: 15 projects with the lowest EAc6 achievement (Group 1) and 15 projects with the highest EAc6 achievement (Group 2). To reach the gold certification level in Group 1, high achievement in EAc6 is associated with low achievement in two indoor environmental quality credits (EQc2, low-emitting materials, and EQc8, quality views), while in Group 2, low achievement in EAc6 is associated with high achievement in EQc2 and EQ8. For the life-cycle assessment (LCA), the functional unit was designated as follows: production (P) stage: production of building materials needed to ensure the requirements of EQc2 and EQc8 for 1 m2 of the building area; and operational energy (OE) stage: OE of 1 m2 of the building area over 50 years of the building’s lifetime. For the OE stage, two fuel source scenarios were used: 71.07% coal + 28.08% natural gas + 0.81% wind power (WP) + 0.04% photovoltaic (PV) (Scenario 1) and 50% WP + 50% PV (Scenario 2). The results of the LCA (P + OE) showed that under Scenario 1, the LEED certification strategy in Group 1 was greener than that in Group 2. When using Scenario 2, no differences were found between the two groups.