A fundamental study of intelligent building envelope systems capable of passive dehumidification and solar heat collection utilizing renewable energy

Lee, Hak Sung; Ozaki, Akihito; Lee, Myonghyang; Cho, Wanghee

doi:10.1016/j.enbuild.2019.04.039

Cited by 24 publications

(8 citation statements)

References 21 publications

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“…As a result, the room temperature was increased by 3.6°C, and the relative humidity of the room was increased by approximately 10% compared with that of the conventional Type N. Furthermore, it was found that in the southern area (Area 7), having very high amounts of solar radiation (H-3), it was possible to reduce the load on Type C systems by~80% compared with that of Type N. Because the installation costs depend on the contractor's skill, as reported in our previous paper [11,14] regarding the construction case of introducing indoor air instead of outside air into the roof's ventilated cavity, it is judged that there will be no significant difference in installation cost provided the installer has the required technical skill. The difference in electricity bill related to power consumption will vary depending on the specifications of the air conditioner and the characteristics of the equipment; however, it will be similar to the reduction ratio of the heat load between the proposed and conventional systems.…”

Section: Discussionmentioning

confidence: 77%

“…As a result, the energysaving effect was approximately 30%, and the reduction effect of peak heat load compared with that of a general house structure was confirmed via radiant cooling and cooling storage during summer and solar heat collection and heat storage during winter [12,13]. Additionally, the authors have reported a novel system capable of passive dehumidification and radiative cooling during hot and humid summer months alongside solar heat collection and humidity control during cold and dry winter months using roof-ventilated cavities and indoor air circulation [14,15]. Martin-Escudero et al [16] estimated the energy capabilities of a photovoltaic ventilated façade coupled to an air-source heat-pump system for heating and domestic hot water.…”

Section: Introductionmentioning

confidence: 89%

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Performance Improvement Plan of Air Circulation-Type Solar Heat-Storage System Using Ventilated Cavity of Roof

et al. 2021

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Indoor solar-heating systems that use ventilated roofs have drawn attention in recent years. The effectiveness and efficiency of such air-heating systems vary depending on the design and operation methods. In Japan, by introducing outside air into a ventilated roof cavity and circulating the air indoors, systems that simultaneously obtain ventilation, solar heating, and heat-storage effects have been actively developed. The conventional systems intake a large volume of outside air to increase the solar heat collection effect. However, there is a risk of heat loss and over-drying when a large amount of cold dry air during winter is introduced. In this paper, plans are presented for improving these solar heating and heat-storage effects by preventing over-drying using indoor air circulation via ventilated cavities in the roof and indoor wall. By comparing the results of the proposed system with those of the conventional system via numerical simulation, the heating load is found to be reduced by 50% or more by circulating indoor air to the ventilated roof and storing the heat in the indoor wall. Moreover, an increased relative humidity of approximately 10% was confirmed by reducing the intrusion of the outside air and keeping the moisture indoors.

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Section: Discussionmentioning

confidence: 77%

Section: Introductionmentioning

confidence: 89%

Performance Improvement Plan of Air Circulation-Type Solar Heat-Storage System Using Ventilated Cavity of Roof

et al. 2021

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“…11,12 There have been a number of simulation calculations for aerogel applications in solar energy collection 13 and building energy efficiency. 14 However, only a few experiments have prepared aerogels with low thermal conductivity and high light transmittance for practical solar thermal collection. Among them, silica aerogel 15 is the most popular heat-insulating and light-transmitting aerogel material due to its low density, 16 high transparency, 17 and ultralow thermal conductivity, 18 which makes it possible to be used in the fields of smart heat-insulated windows and solar collectors.…”

Section: ■ Introductionmentioning

confidence: 99%

“…Many researchers have proved that transparent and thermal insulated aerogels are one of the most promising materials for thermal insulation along with transmission of solar energy. , There have been a number of simulation calculations for aerogel applications in solar energy collection and building energy efficiency . However, only a few experiments have prepared aerogels with low thermal conductivity and high light transmittance for practical solar thermal collection.…”

Section: Introductionmentioning

confidence: 99%

Polyimide Aerogel Membranes with Adjustable Transparency and High Flexibility for Highly Efficient Solar Thermal Collection

Hou

Zhang

Fang

2021

ACS Sustainable Chem. Eng.

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Aerogel-based solar collectors inherently possess superinsulated performance, which can achieve green and sustainable thermal collection under atmospheric pressure without the need of a vacuum gap. However, the inherent brittleness, low transparency, and weak mechanical properties of aerogels limit the practical application as solar collectors. Herein, polyimide aerogel membranes (PIAMs) with integrated properties of robust flexibility, high transparency, and low thermal conductivity have been prepared. The prepared PIAMs achieve the adjustable transparency and significant transformation from fragility to high flexibility by introducing the asymmetric molecular structure. In particular, the prepared PIAMs realize an average optical transmittance of ∼90% over the long wavelength range of 500–2650 nm and exhibit high flexibility, a low density of 0.161 g/cm3, a low thermal conductivity of 0.045 W/mK, and a robust tensile strength of 6.02 MPa. Moreover, a simple and low-cost parabolic trough solar collecting device is assembled using PIAMs as an exterior structure, which could operate at atmospheric conditions and achieve highly efficient thermal collection. The results demonstrate that the effective thermal collecting temperature of solar collector was up to 231.5 °C. The as-prepared PIAMs with robust flexibility and high optical transparency can be used as the candidate for the application of solar collectors and advanced optical elements.

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“…Normally, water vapor is eliminated by air exchange, either by a natural air leak through the building envelope, by mass diffusion through the structure or by natural or controlled mechanical ventilation. It can also be removed with classical dehumidification equipment, but residential dehumidifiers have limited ability to remove moisture during winter due to low air temperatures [11]. Thermoelectric coolers and dessicant materials-based systems can also be used, but the humidity transfer rates are generally low [12].…”

Section: Introductionmentioning

confidence: 99%

An Innovative System for the Treatment of Rising Dampness in Buildings Located in Cold Climates

et al. 2021

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Signs of wetness in housing are a significant obstacle to the renovation and energy rehabilitation of old and energy-intensive heritage buildings, especially in cold climates. Thus, in order to avoid the numerous possibilities of degradation caused by the moisture transfer phenomena in the building envelope, the a disruptive aeraulic process, which focuses on the ventilation of an air gap between the thermal insulation and the wet wall, has been designed and its assessed. This system avoids the presence of liquid water at the wall surface by maintaining the hygrothermal balance within the wet wall. This enables the mechanical durability of the supporting structure, the absence of biological activity and/or frost and, hence, the durability of the thermal insulation. These issues are investigated through a case study based on a real site. Over a year of measurements, the wet wall was constantly maintained in hygroscopic balance, around 90% RH, guaranteeing the preservation of its mechanical performance, while the insulation layer was kept moisture free. In addition, the proposed model for predicting the appearance and development of biological activity demonstrated its validity, confirming experimental results.These initial results will now lead to the optimization of the aeraulic device, as well as possible use in a summer cooling context to achieve hygrothermal comfort for housing occupants.

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A fundamental study of intelligent building envelope systems capable of passive dehumidification and solar heat collection utilizing renewable energy

Cited by 24 publications

References 21 publications

Performance Improvement Plan of Air Circulation-Type Solar Heat-Storage System Using Ventilated Cavity of Roof

Performance Improvement Plan of Air Circulation-Type Solar Heat-Storage System Using Ventilated Cavity of Roof

Polyimide Aerogel Membranes with Adjustable Transparency and High Flexibility for Highly Efficient Solar Thermal Collection

An Innovative System for the Treatment of Rising Dampness in Buildings Located in Cold Climates

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