Investigation of heat transfer of a building wall in the presence of phase change material(PCM)

The energy consumption in buildings for heating,ventilation,and air-conditioning is increasing with the in-creasing demand for thermal comfort.Thermal energy storage with phase change material(PCM)has attracted growing attention for its role in achieving energy conservation in buildings with thermal comfort.This paper investigates the effect of PCM on the heat transfer rate in a building wall and the role of PCM on the indoor thermal comfort of the building.Two models of building wall fragments were developed for the experimental study.In one model,tests were conducted for different positions of the PCM layer in the building wall to identify the optimal position of the PCM layer inside the wall.In another model,tests were carried out integrating PCM,air gap,and other conventional building materials(brickbat and sand),one at a time,to investigate the role of PCM on the heat transfer rate in the building wall fragment.The results show that placing the PCM layer closer to the heat source gives a low-temperature gain of the cold water bath(indoor state)as compared with the PCM layer near the heat sink.With PCM,the temperature rise of the cold water bath(indoor state)of the building wall fragment was the lowest,and the slope of the temperature rise of the cold water bath becomes steadier with time i.e.,fewer temperature fluctuations.There was a significant time delay for the cold water bath to reach a given temperature.The heat required for a unit degree increase in the temperature of the cold water bath was higher and the peak heat flux of the wall was lower relative to the other building materials.

Preparation of Styrene-acrylate Latex Used in Ultralow VOC Building Internal Wall Coating

Styrene-acrylate latex with high glass transition temperature （T）, low minimum film forming temperature（MFT） and good stability was prepared via core-shell emulsion polymerization. With semicontinuous process, high conversion rate of monomer and low gel rate were achieved. The weight ratio of core monomer to shell monomer was approximately 1.35. It is found that many factors such as emulsifiers, initiators, reaction temperature, pH value and polymerization technology have influences on the permormance of styrene-acrylate latex. The prepared latex was characterized by TEM and FTIR. The obtained latex with T of 20.57 ℃, MFT or5.0 ℃, and good stability, had good stability of film forming.

Assessment of seismic design response factors of concrete wall buildings

To verify the seismic design response factors of high-rise buildings, five reference structures, varying in height from 20- to 60-stories, were selected and designed according to modern design codes to represent a wide range of concrete wall structures. Verified fiber-based analytical models for inelastic simulation were developed, considering the geometric nonlinearity and material inelasticity of the structural members. The ground motion uncertainty was accounted for by employing 20 earthquake records representing two seismic scenarios, consistent with the latest understanding of the tectonic setting and seismicity of the selected reference region （UAE）. A large number of Inelastic Pushover Analyses （IPAs） and Incremental Dynamic Collapse Analyses （IDCAs） were deployed for the reference structures to estimate the seismic design response factors. It is concluded that the factors adopted by the design code are adequately conservative. The results of this systematic assessment of seismic design response factors apply to a wide variety of contemporary concrete wall buildings with various characteristics.

Building a Great Green Wall

China’s forests are being expanded by tree-planting volunteers and national forestry

Sound Insulation Performance of Structural Wood Wall Integrated with Wood Plastic Composite

The sound insulation performance is an important technical index for evaluating the physical property of the building wall.Three kinds of structural wood walls integrated with wood plastic composite(WPC)were designed.And the sound insulation performance of the walls was studied.The results showed that for the wall that constructed by the WPC as the wall studs,compared with the one that constructed by the pine wood as the wall studs,the deviation of their sound insulation was lower than±3 dB.The wall’s external panel material had significant effect on the wall’s sound insulation property,and the contribution of the wood-plastic panel to the sound insulation was much higher than that of the polyvinyl chloride(PVC)plastic hanging board.The surrounding sealing quality of the wall’s external panel material had an important influence on the sound insulation effect of the building wall,and the panel of the wood plastic interior wall had less influence on the sound insulation performance of the wall.Taking the sound-absorbing cotton or non-woven fabric as elastic strips was an effective technical measure to improve the sound insulation performance of the walls.The sound insulation was improved by 2.4 dB and 3.1dB respectively after the correction of pink noise spectrum,and increased by 2.8 dB and 3.6 dB respectively after the correction of traffic noise spectrum.