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标题：Minimizing heat transmission loads and improving energy efficiency of building envelopes in sub-Saharan Africa using bio-based composite materials
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作者：Richard Opoku ; George Y. Obeng ; Jo Darkwa 等
期刊名称：Scientific African
印刷版ISSN：2468-2276
出版年度：2020
卷号：8
页码：1-13
DOI：10.1016/j.sciaf.2020.e00358
语种：English
出版社：Elsevier
摘要：Highlights•Thermal properties of sandcrete building blocks can be improved with plant-based materials.•Improved bio-based composite materials enhance energy efficiency of building envelopes.•Wall heat transmission load is minimized with bio-based composite building materials.•Bio-based building walls result in significant reduction in air-conditioner electricity consumption.AbstractIncreasing effect of climate change coupled with global warming has necessitated the need for mechanical cooling in buildings to provide indoor thermal comfort. Many countries in tropical climates, particularly in sub-Saharan Africa, use sandcrete blocks for constructing building envelopes which have relatively high thermal conductivity. This leads to increased heat transmission through the building walls resulting in increased building electricity consumption using air-conditioners. This study focused on opportunity of minimizing the thermal conductivity of sandcrete blocks by mixing it with available bio-based local materials, specifically treated sawdust and palm fibers. Experiments were conducted to determine the thermal conductivity, compressive strength and densities of sandcrete mixed with 10%, 20%, 30% and 40% of treated sawdust and palm fiber to form building block composites. The study results showed that incorporating the bio-based material into the sandcrete decreases its density and thermal conductivity, thereby decreasing the wall heat transmission load. Using a minimum standard limit of 3 MPa for compressive strength for building envelopes, the composite samples: S10, P10, P20 and P30 were found to be appropriate to be used to minimize wall heat transmission. The composite of 70% sandcrete with 30% treated palm fiber (P30) exhibited the best thermal performance with 38% reduction in thermal conductivity compared to the control sandcrete block. Maximum wall heat flux reduction of 52 W/m2was attained at peak load with the composite P30 compared to the control sample P0 (100% sandcrete). In addition, using the degree-days cooling for Ghana, the analysis indicated maximum electricity saving potential of 453.40 kWh per year for an office space cooling using the sandcrete-palm fiber composite P30 as the building envelope.
关键词：KeywordsBio-based composite blocksEnergy efficient building materialsWall transmission loadThermal conductivityCompressive strength