Thermal performance evaluation and comfort assessment of advanced aerogel as blown-in insulation for historic buildings

Lucchi, Elena; Becherini, Francesca; Tuccio, Maria Concetta Di; Troi, Alexandra; Frick, Jürgen; Roberti, Francesca; Hermann, Carsten; Fairnington, Ian; Mezzasalma, Giulia; Pockelé, Luc; Bernardi, Adriana

doi:10.1016/j.buildenv.2017.06.019

Cited by 58 publications

(27 citation statements)

References 12 publications

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“…It is manufactured from different types of gels by supercritical drying; silica alco-gels are the most widely manufactured, which are most regularly prepared from silica gel [6][7][8][9][10][11]. In many papers, in the systematic literature, investigations of aerogel-related contents can be found, but due to a lack of space, only some of them can be presented as well as processed in the introduction part of this paper [12][13][14]. The main goal of this paper is to present and understand experimental results carried out on glass fiber-reinforced aerogel samples.…”

Section: Introductionmentioning

confidence: 99%

Effects of the Heat Treatment in the Properties of Fibrous Aerogel Thermal Insulation

et al. 2019

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Nowadays, besides the use of conventional insulations (plastic foams and wool materials), aerogels are one of the most promising thermal insulation materials. As one of the lightest solid materials available today, aerogels are manufactured through the combination of a polymer with a solvent, forming a gel. For buildings, the fiber-reinforced types are mainly used. In this paper, the changes both in the thermal performance and the material structure of the aerogel blanket are followed after thermal annealing. The samples are put under isothermal heat treatments at 70 °C for weeks, as well as at higher temperatures (up to 210 °C) for one day. The changes in the sorption properties that result from the annealing are presented. Furthermore, the changes in the thermal conductivity are followed by a Holometrix Lambda heat flow meter. The changes in the structure and surface of the material due to the heat treatment are investigated by X-ray diffraction and with scanning electron microscopy. Besides, the above-mentioned measurement results of differential scanning calorimetry experiments are also presented. As a result of using equipment from different laboratories that support each other, we found that the samples go through structural changes after undergoing thermal annealing. We manifested that the aerogel granules separate down from the glass fibers and grow up. This phenomenon might be responsible for the change in the thermal conductivity of the samples.

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Section: Introductionmentioning

confidence: 99%

Effects of the Heat Treatment in the Properties of Fibrous Aerogel Thermal Insulation

et al. 2019

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“…It is reported by several authors that aerogel is one of the most important super-insulation materials, having a lower thermal conductivity of the air under normal circumstances as well as having lower thermal conductivity than 0.018 W/(m K). In the literature, it was presented several times that moisture and humid environments have a significant effect on the thermal insulation capability of this material [14][15][16][17][18][19]. It was further shown that thermal annealing has an effect on both the structure and the chemical composition of the aerogel [20][21][22].…”

Section: Introductionmentioning

confidence: 97%

Thermal Diffusion in Fibrous Aerogel Blankets

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Trník

2020

Energies

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Nowadays, the usage of thermal insulation materials is widespread not only in the building sector but also in the vehicle industry. The application of fibrous or loose-fill insulation materials like glass wool or mineral wool as well as aerogel is well known. Aerogel-based materials are among the best solid materials for thermal insulation available today; they are prepared through a sol–gel process. For building walls, the glass-fiber-enhanced types are the frequently used ones. They are prepared by adding the liquid–solid solution to the fibrous batting, which is called a sol–gel process. In the present paper, the changes in the most important building physical properties of aerogel blankets after thermal annealing are presented. The samples were subjected to isochronal heat treatments from 70 to 210 °C for 24 h. The changes in the thermal conductivity were followed by Holometrix Lambda heat flow meter, and differential scanning calorimetry results were also recorded. From the measured values, together with the densities, the most important thermal properties were calculated, such as thermal resistance, diffusivity, effusivity (heat absorption), and thermal inertia. In this paper, we attempt to clarify the role played by thermal annealing in the transient thermal properties of aerogel materials. Besides presenting the measurement results, a theoretical background is given. The investigations of not only the steady-state but also the transient thermal parameters of the materials are momentous at the design stage.

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“…HVAC energy demand is directly related to the indoor temperature setpoint, air infiltration, incident solar radiation, window type, window-wall ratio, internal loads, building type and climate [2]. An adequate evaluation of the thermal performance of the building envelope is needed [3,4], because it will influence the thermal load of the air-conditioned compartments and, therefore, the HVAC performance. Indeed, the building envelope data (type of elements and their dimensions) is an important step in a building thermal behavior numerical simulation [5].…”

Section: Introductionmentioning

confidence: 99%

HVAC Systems Applied in University Buildings with Control Based on PMV and aPMV Indexes

et al. 2019

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In this work, HVAC (Heating, Ventilation and Air Conditioning) systems applied in university buildings with control based on PMV (Predicted Mean Vote) and aPMV (adaptive Predicted Mean Vote) indexes are discussed. The building’s thermal behavior with complex topology, in transient thermal conditions, for summer and winter conditions is simulated by software. The university building is divided into 124 spaces, on two levels with an area of 5931 m2, and is composed of 201 transparent surfaces and 1740 opaque surfaces. There are 86 compartments equipped with HVAC systems. The simulation considers the actual occupation and ventilation cycles, the external environmental variables, the internal HVAC system and the occupants’ and building’s characteristics. In this work, a new HVAC control system, designed to simultaneously obtain better occupants’ thermal comfort levels according to category C of ISO 7730 with less energy consumption, is presented. This new HVAC system with aPMV index control is numerically implemented, and its performance is compared with the performance of the same HVAC system with the usual PMV index control. Both HVAC control systems turn on only when the PMV index or the aPMV index reaches values below −0.7, in winter conditions, and when the PMV index or the aPMV index reaches values above +0.7, in summer conditions. In accordance with the results obtained, the HVAC system guarantees negative PMV and aPMV indexes in winter conditions and positive PMV and aPMV indexes in summer conditions. The energy consumption level is higher in winter conditions than in summer conditions for compartments with shading, and it is lower in winter conditions than in summer conditions for compartments exposed to direct solar radiation. The consumption level is higher using the PMV control than with the aPMV control. Air temperature, in accordance with Portuguese standards, is higher than 20 °C in winter conditions and lower than 27 °C in summer conditions. In Mediterranean climates, the HVAC systems with aPMV control provide better occupants’ thermal comfort levels and less energy consumption than the HVAC system with PMV control.

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Thermal performance evaluation and comfort assessment of advanced aerogel as blown-in insulation for historic buildings

Cited by 58 publications

References 12 publications

Effects of the Heat Treatment in the Properties of Fibrous Aerogel Thermal Insulation

Effects of the Heat Treatment in the Properties of Fibrous Aerogel Thermal Insulation

Thermal Diffusion in Fibrous Aerogel Blankets

HVAC Systems Applied in University Buildings with Control Based on PMV and aPMV Indexes

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