More Like this

1. Ultralight and Flexible Monolithic Polymer Aerogel with Extraordinary Thermal Insulation by A Facile Ambient Process

   https://doi.org/10.1002/admi.201900314  

   Li, Man; Qin, Zihao; Cui, Ying; Yang, Chiyu; Deng, Changyu; Wang, Yunbo; Kang, Joon_Sang; Xia, Hongyan; Hu, Yongjie (May 2019, Advanced Materials Interfaces)

   Abstract High performance thermal insulation materials are desired for a wide range of applications in space, buildings, energy, and environments. Here, a facile ambient processing approach is reported to synthesize a highly insulating and flexible monolithic poly(vinyl chloride) aerogel. The thermal conductivity is measured respectively as 28 mW (m K)⁻¹at atmosphere approaching the air conductivity and 7.7 mW (m K)⁻¹under mild evacuation condition. Thermal modeling is performed to understand the thermal conductivity contributions from different heat transport pathways in air and solid. The analysis based on the Knudsen effect and scattering mean free paths shows that the thermal insulation performance can be further improved through the optimization of porous structures to confine the movement of air molecules. Additionally, the prepared aerogels show superhydrophobicity due to the highly porous structures, which enables new opportunities for surface engineering. Together, the study demonstrates an energy‐saving and scalable ambient‐processing pathway to achieve ultralight, flexible, and superhydrophobic poly(vinyl chloride) aerogel for thermal insulation applications. 

   more » « less
2. Emerging investigator series: primary emissions, ozone reactivity, and byproduct emissions from building insulation materials

   https://doi.org/10.1039/c9em00024k  

   Chin, Kyle; Laguerre, Aurelie; Ramasubramanian, Pradeep; Pleshakov, David; Stephens, Brent; Gall, Elliott T. (August 2019, Environmental Science: Processes & Impacts)

   Building insulation materials can affect indoor air by (i) releasing primary volatile organic compounds (VOCs) from building enclosure cavities to the interior space, (ii) mitigating exposure to outdoor pollutants through reactive deposition (of oxidants, e.g. , ozone) or filtration (of particles) in infiltration air, and (iii) generating secondary VOCs and other gas-phase byproducts resulting from oxidant reactions. This study reports primary VOC emission fluxes, ozone (O 3 ) reaction probabilities ( γ ), and O 3 reaction byproduct yields for eight common, commercially available insulation materials. Fluxes of primary VOCs from the materials, measured in a continuous flow reactor using proton transfer reaction-time of flight-mass spectrometry, ranged from 3 (polystyrene with thermal backing) to 61 (cellulose) μmol m −2 h −1 (with total VOC mass emission rates estimated to be between ∼0.3 and ∼3.3 mg m −2 h −1 ). Major primary VOC fluxes from cellulose were tentatively identified as compounds likely associated with cellulose chemical and thermal decomposition products. Ozone-material γ ranged from ∼1 × 10 −6 to ∼30 × 10 −6 . Polystyrene with thermal backing and polyisocyanurate had the lowest γ , while cellulose and fiberglass had the highest. In the presence of O 3 , total observed volatile byproduct yields ranged from 0.25 (polystyrene) to 0.85 (recycled denim) moles of VOCs produced per mole of O 3 consumed, or equivalent to secondary fluxes that range from 0.71 (polystyrene) to 10 (recycled denim) μmol m −2 h −1 . Major emitted products in the presence of O 3 were generally different from primary emissions and were characterized by yields of aldehydes and acetone. This work provides new data that can be used to evaluate and eventually model the impact of “hidden” materials ( i.e. , those present inside wall cavities) on indoor air quality. The data may also guide building enclosure material selection, especially for buildings in areas of high outdoor O 3 . 

   more » « less
3. Characterization and Performance Enhancement of Cement-Based Thermoelectric Materials

   https://doi.org/10.3390/polym14122311  

   Jani, Ruchita; Holmes, Niall; West, Roger; Gaughan, Kevin; Liu, Xiaoli; Qu, Ming; Orisakwe, Esther; Stella, Lorenzo; Kohanoff, Jorge; Yin, Hongxi; et al (June 2022, Polymers)

   Thermoelectric materials enable the direct conversion of thermal to electrical energy. One application of this is ambient heat energy harvesting where relatively stable temperature gradients existing between the inside and outside of a building could be utilized to produce electricity. Buildings can thus change from energy consumers to energy generators. This could ultimately help reduce the surface temperatures and energy consumption of buildings, especially in urban areas. In this paper, research work carried out on developing and characterizing a cement-based thermoelectric material is presented. Cement-based samples are doped with different metal oxides (Bi2O3 and Fe2O3) to enhance their thermoelectric properties, which are defined through their Seebeck coefficient, electrical conductivity and thermal conductivity. The study also discusses the positive impact of moisture content on the electrical conductivity 

   more » « less
4. Adaptive Segmentation of Thermal Anomalies in Buildings Using Human-in-the-Loop Active Learning Capsule Networks

   https://doi.org/10.7771/3067-4883.1830  

   Wen, Yining; Chen, Kaiwen (June 2025, CIB Conferences)

   Buildings account for 40% of energy consumption in the U.S., with significant energy losses stemming from poor insulation and leaks. To meet decarbonization goals by 2050, efficient methods for diagnosing and retrofitting thermal anomalies are essential. Infrared thermography (IRT), combined with emerging technologies like computer vision and deep learning, offers the potential for automating thermal anomaly detection and segmentation. However, challenges such as building diversity, scenario variations, and labor-intensive image annotation hinder model reliability and robustness. This study proposes a human-in-the-loop active learning approach to fine-tune the pretrained Capsule-based network (CapsLab) to enhance adaptability to new building scenarios efficiently. Using a Query-by-Committee (QBC) strategy, the method selects the most informative thermal images from a target dataset for expert verification and iterative model refinement. To streamline the expert annotation verification process, a weakly annotation strategy is introduced supporting human-in-the-loop training by Simple Linear Iterative Clustering (SLIC)-based superpixel segmentation and scribble prompts for efficient labeling. The pretrained CapsLab model is iteratively fine-tuned using these verified annotations to enhance segmentation performance. Three fine-tuning methods, including parameter freezing strategies, are evaluated for optimal results. This iterative workflow reduces annotation effort, improves model adaptability, and improves the precision of thermal anomaly segmentation, facilitating energy-efficient building retrofitting and maintenance. 

   more » « less
5. Thermal Comfort: Radiant Systems - A Review of Experimentalbased thermal comfort research in Radiation systems

   JAWADWALA, HUZEFA; TIAN, ROBERT; YIN, HONGXI; QU, MING; LIU, XIAOLI; HOLMES, NIALL; KOHANOFF, JORGE; JANI, RUCHITA (March 2021, 108th ACSA Annual Meeting Proceeding)

   null (Ed.)

   Buildings use 40% of the global energy consumption and emit 30% of the CO2 emissions [1]. Of the total building energy, 30-40% are for building heating and cooling systems, which regulate the indoor thermal environment and provide thermal comfort to occupants. In the United States, most buildings use forced air technology to deliver heating/cooling to the targeted thermal zones. However, this system may cause complaints about thermal comfort from inhabitants due to excessive draft movement, inhomogeneous conditioning, and difficulty in accurately controlling the temperature for a system serving multiple rooms. Therefore, researchers have suggested using a radiant heating and cooling system as a better alternative to all-air systems to address these issues. Radiant systems supply heating or cooling directly to the building space using radiation released by the heated or cooled building enclosure via the embedded heating or cooling tubes. In the cooling season, the radiant system often works with a separated dehumidifier to meet space latent and sensible cooling load (called separate sensible and latent cooling system SSLC). The SSLC has shown higher efficiency than forced air systems. However, it is unsure whether the radiant heating and cooling system can provide better thermal comfort to occupants. Moreover, the evaluation method for thermal comfort in the current standard is suitable for forced air systems. Therefore, a new method shall be developed to evaluate the radiation system’s thermal comfort. In this paper, we review the experiment-based studies on the thermal comfort of radiant systems. According to the experimental studies regarding thermal comfort and radiant systems, the key findings are concluded to help guide the evaluation of thermal comfort for radiant systems. 

   more » « less