著者

岸本 尚子 齋藤 宏昭 野中 俊宏 齊藤 孝一郎

出版者

一般社団法人 日本建築学会

雑誌

日本建築学会技術報告集 (ISSN:13419463)

巻号頁・発行日

vol.26, no.64, pp.995-1000, 2020-10-20 (Released:2020-10-20)

参考文献数

8

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Thermal bridges at the connections between window and wall are generally not added to evaluation of heat loss from building envelopes. This report presents evaluation method for the thermal bridge around the window. Linear thermal transmittance between window and wall in typical configurations was calculated as an evaluation index. In addition, quantities of the heat loss from the thermal bridge were compared with the total heat loss amount of a house.

著者

梅野 徹也 鉾井 修一 齋藤 宏昭 本間 義規

出版者

日本建築学会

雑誌

日本建築学会環境系論文集 (ISSN:13480685)

巻号頁・発行日

vol.81, no.729, pp.951-959, 2016 (Released:2016-11-30)

参考文献数

17

被引用文献数

1 2

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Most exterior walls of wooden residential buildings in Japan have a vented air space between the exterior cladding and insulation. This air space is designed to dehumidify exterior walls by discharging humidity to the outside and taking outdoor air into the walls, in order to decrease the risk of condensation on exterior walls in winter. Many studies have been carried out on vented air space, and the most effective thickness for dehumidification has been determined. However, most of these studies have only investigated the performance of vented air spaces under laboratory conditions, and the characteristics of vented air spaces in the field have not been clarified. Our previous study clarified the characteristics of ventilation volume through the vented air space based on field measurements. This study continues that work by reporting on the hygro-thermal characteristics of vented air space. Temperature and humidity were measured in an experimental house built in Iwate prefecture, and the hygro-thermal characteristics of the vented air space were verified. Temperature and humidity in the vented air space were affected by the outdoor temperature and humidity during most periods of time, except when the wall was exposed to solar radiation. Indoor temperature and humidity had less of an effect on the vented air space, because the walls of the experimental house are well insulated and highly moisture proof. The temperature of the vented air space is 20 or 30 degrees higher than the outdoor temperature when exposed to the sun during the day, and the humidity of the vented air space also rises. It is thought that the rise in humidity is due to moisture desorption from the exterior cladding. The vented air space of the east wall that is exposed to the sun in the early morning tends to have high humidity for a short time because moisture desorption from exterior cladding occurs when the temperature of the wall is low. Solar radiation on the wall also produces a temperature difference between the vented air space and the outside that is one of the driving forces of ventilation in the vented air space. So ventilation volume tends to be high when the wall is exposed to the sun, and low at night time. This means that ventilation volume in the vented air space is high during moisture desorption from the exterior wall cladding and low during moisture absorption. As a result, most of the desorbed moisture from the exterior cladding is discharged well by the ventilation, and the absolute humidity in the vented air space is kept lower than that outdoors. Through long-term measurement of the hygro-thermal characteristics of the vented air space, it was shown that absolute humidity of the vented air space is lower on the average than the outdoor air due to daily variation in ventilation volume and moisture absorption by the exterior cladding. A numerical simulation was conducted and the results of the field survey were simulated. The hygro-thermal characteristics of the vented air space, moisture absorption by the exterior cladding and drying of the vented air space over the long term were generally confirmed.

著者

齋藤 宏昭 三浦 尚志 桑沢 保夫

出版者

日本建築学会

雑誌

日本建築学会環境系論文集 (ISSN:13480685)

巻号頁・発行日

vol.78, no.688, pp.461-470, 2013-06-30 (Released:2013-08-30)

参考文献数

13

被引用文献数

2 1

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This study focuses on impact of vapor proofing and airtightness on hygrothermal performance for wooden exterior walls. Partial air and moisture penetration into fibrous insulation layer of the wall were mainly addressed in terms of practical issue for the hygrothermal design. Laboratory experiments using wall assemblies with partial defects for vapor proofing such as outlet were implemented to better understand moisture distribution and air flow within the walls when pressure difference occurs between the indoor and the outdoor rooms. After a developed HAM analysis model was verified by the lab-experiments, long-term simulations were performed to clarify moisture accumulation within the wall under various climate conditions. The simulation results indicated that requirements of both the vapor proofing and the air tightness can be mitigated in mild climate regions. Additionally, the results showed that the partial defect at the top of walls causes the moisture accumulation.

著者

葛野 耕司 齋藤 宏昭 佐伯 智寛 水藤 聡

出版者

一般社団法人日本建築学会

雑誌

学術講演梗概集 (ISSN:18839363)

巻号頁・発行日

vol.2015, pp.217-218, 2015-09-04

著者

梅野 徹也 鉾井 修一 齋藤 宏昭 本間 義規

出版者

日本建築学会

雑誌

日本建築学会環境系論文集 (ISSN:13480685)

巻号頁・発行日

vol.78, no.694, pp.909-916, 2013-12-30 (Released:2014-07-10)

参考文献数

14

被引用文献数

2 2

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Most exterior walls of wooden residential buildings in Japan have vented air space between the exterior cladding and the insulation, which is designed to dehumidify the exterior walls by discharging humidity to the outside and taking outdoor air into the walls, with the purpose of decreasing the risk of condensation in exterior walls in winter. Several studies have been carried out on the vented air space, and the most effective thickness for dehumidification has been determined. However, most of these studies have only investigated the performance of vented air spaces under laboratory conditions, and the characteristics of vented air spaces in a field environment have not been clarified. The driving forces of the airflow in the vented air space are the buoyancy force due to the temperature difference between the outdoor air and the vented air space and the wind pressure. However, few studies have dealt with the influence of wind pressure. Since the velocity and the direction of the wind change irregularly, it is difficult to estimate the ventilation volume due to the wind. The objective of this study is to survey the ventilation volume through the vented air space and to investigate the effect of the driving force of the ventilation, which are buoyancy force and wind. Measurements have been carried out on the vented air space in an experimental wooden house that has several types of vented air spaces. The correlation between the ventilation volume and the driving force was discussed.