Thermal performance and service life of vacuum insulation panels with aerogel composite cores

Liang, Yingjing; Wu, Huijun; Huang, Gongsheng; Yang, Jianming; Wang, Huan

doi:10.1016/j.enbuild.2017.08.085

Cited by 105 publications

(27 citation statements)

References 46 publications

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“…Building envelopes consist of different structural and functional components, such as windows, walls, floors, and roofs; each of them plays an important role on the overall energy efficiency. Different technologies could be considered to improve building energy performance, especially focusing on the transparent elements; highly insulating glazing windows have been under rapid development in the last years and some commercial products have been used in many applications, both for new buildings and refurbishment [1,2]. A glazing system with aerogel filling is proposed as a technology able to offer natural light, with the advantage of better thermal insulation performance with respect to traditional double and triple glazing solutions [3,4].…”

Section: Introductionmentioning

confidence: 99%

Experimental and Numerical Energy Assessment of a Monolithic Aerogel Glazing Unit for Building Applications

et al. 2019

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In the last few decades, the attention of researchers has been focused on the characterization of aerogels in order to improve the thermal performance of transparent building envelopes. Granular aerogel is already spread in the market thanks to the easy manufacturing system, whereas the difficulty in producing monoliths without defects, cracks, and inhomogeneity limited the diffusion of monolithic aerogel systems. A new production process for the monolithic panels was developed at Union College (Schenectady, NY, USA); it is a rapid supercritical extraction technique which allows a reduction in production time (only a few hours) and results in less solvent waste. Panes with maximum dimensions of about 100 × 100 mm were fabricated and composed in a unique glazing system, with external dimensions 300 × 300 mm. The thermal characterization of the innovative monolithic aerogel glazing system (simple float glazing 4.7-mm-thick monolithic aerogel pane 15-mm-thick simple float glazing 4.7 mm thick), which was carried out by means of a Small Hot Box apparatus, showed a thermal transmittance value of about 1.1 W/(m 2 K). Data was used in dynamic simulations of a typical non-residential building. They showed that the new investigated solution allows a valuable reduction with respect to a low-e double glazing system in terms of heating energy demand (about 5-7% for Helsinki, 8-12% for Paris, and 10-15% for Turin), for different window-to-wall ratios. monolithic form is the difficulty in fabrication of samples without defects, cracks, and inhomogeneity, and their high cost [5]. In the last years, a rapid supercritical extraction method was developed at Union College (Schenectady-NY), allowing a significant reduction in fabrication times (6-8 hours) and in solvent waste. Good optical properties can be obtained (τ v > 80%); when assembled with two glasses (total thickness 22 and 12.7 mm of aerogel), a thermal resistance of 0.86 and 1.55 m 2 K/W is obtained at atmospheric pressure and in evacuated conditions, respectively [6,7].Guoqing Zu et al. evaluated the thermal performance of monolithic alumina aerogel systems, prepared by a sol-gel method combined with the ethanol supercritical drying technique [8]. The thermal conductivities at 30 • C and 400 • C were 0.028 and 0.065 W/mK, respectively [8]. Duer and Svendsen [9] presented the main results of a research project founded by the European Commission. They discussed an aerogel pane prototype of 450×450x15 mm 3 , made under vacuum conditions and sandwiched between two glasses; a conductivity value of about 0.010 W/mK was measured at ambient temperature.Another interesting study presents a detailed investigation of the mechanical microstructural and thermal properties of monolithic aerogels made from polyethoxydisiloxane [10]. The thermal conductivity is highly dependent on the densities of monolithic panes; a minimum value of 0.0135 W/mK was measured for a density of 120 kg/m 3 , a maximum value of 0.024 W/mK for about 300 kg/m 3 . Similar values of thermal conductivity were fo...

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Section: Introductionmentioning

confidence: 99%

Experimental and Numerical Energy Assessment of a Monolithic Aerogel Glazing Unit for Building Applications

et al. 2019

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“…On the other hand, only some secondary and renewable materials can be used for VIPs because they need to meet certain limits of the particle size/fiber length and thickness, and need to be chemically pure enough to avoid low-pressure sublimation of unstable compounds (outgassing), which causes thermal-insulation properties to deteriorate after vacuum sealing. 3 Research has found that fibers obtained by pulping waste textile produced by both textile manufacturing and recycling have very interesting properties and are, in most cases, well suited for use in various thermal-and acoustic-insulation materials. In addition, polymer fibers can be made into a matrix, suitable for VIPs.…”

Section: Introductionmentioning

confidence: 99%

Polymer-matrix-bonded polyester fibers as a substitute for materials used for the cores of vacuum insulation panels

Zach¹,

Novák²

2019

Mater. Tehnol.

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The paper discusses the use of alternative raw materials for the manufacturing of VIPs (vacuum insulation panels). VIPs are thermally insulating boards with a fibrous core at an extremely low pressure. The research is focused on substituting glass fibers with polyester fibers in VIP cores. Polyester fibers are thermally bonded using BiCo fibers, which, once they have cooled down, form the matrix of a composite VIP core. It is proved that polyester fibers bonded with BiCo fibers show great promise, most notably in terms of their excellent thermal-insulation properties, which they retain for a long time.

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“…The detailed computation and associated analysis of secondorder partial can be found in the works [53][54][55]. The secondorder partial derivative of sum ( ) is calculated as We found that 2 sum ( )/ 2 < 0 due to the value of numerator is a negative; this shows that the function sum ( ) is concave with respect to .…”

Section: B Proof Of Corollarymentioning

confidence: 99%

Low Cost and High Efficiency Hybrid Architecture Massive MIMO Systems Based on DFT Processing

Tan

Carvalho

et al. 2018

Wireless Communications and Mobile Computing

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Low cost and high efficiency, defined as energy efficiency (EE) and spectral efficiency (SE), have raised more and more attention in the fifth generation (5G) communication systems due to steadily rising hardware cost, energy consumption, and mobile traffic. This paper studies the hybrid architecture of multiuser massive MIMO systems, where the digital domain utilizes the zero-forcing (ZF) precoding scheme and the analog domain uses discrete Fourier transform (DFT) processing that significantly reduces hardware cost and energy consumption. We derive analytical expressions on the total achievable SE and EE, as well as offering insight into some engineering parameters in the system performance. Our aim is to achieve low cost and high efficiency massive MIMO system, with constraints on the overall transmit power, the number of users, and the number of radio frequency (RF) chains. Results exhibit that the total achievable SE of the hybrid architectures with DFT precessing is inferior to the full digital architectures and hybrid architectures with the ideal phase shifters, but the performance attenuation can be compensated by providing the more input SNR and higher number of RF chains. Moreover, we find that the total achievable EE of hybrid architectures with DFT precessing outperforms other massive MIMO architectures that include a full digital implementation, ideal phase shifters, and a switched network.

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Thermal performance and service life of vacuum insulation panels with aerogel composite cores

Cited by 105 publications

References 46 publications

Experimental and Numerical Energy Assessment of a Monolithic Aerogel Glazing Unit for Building Applications

Experimental and Numerical Energy Assessment of a Monolithic Aerogel Glazing Unit for Building Applications

Polymer-matrix-bonded polyester fibers as a substitute for materials used for the cores of vacuum insulation panels

Low Cost and High Efficiency Hybrid Architecture Massive MIMO Systems Based on DFT Processing

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