English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

The overall performance of the composite insulation external walls (CIEW) may not be optimal as the current methods calculate the optimal insulation thickness (OIT) considering only the cost due to an increase in the insulation layer. The influence of base wall costs on optimum construction form is worthy of further investigated. This study is to close the knowledge gap to improve the overall performance of a CIEW. For this, an optimization model was established using a life-cycle cost analysis (LCCA) method considering the structural and insulation layers to determinate the optimal structural layer thickness (OSLT), optimal insulation thickness (OIT), and overall U-value of a CIEW. A case study of a masonry wall in a cold area in Beijing was conducted. Coal-fired boiler (CFB), gas-fired boiler (GFB), and air source heat pump (ASHP) were used as heat sources, and extruded polystyrene panel (XPS), rock wool (RW), and glass wool (GW) were used as insulation materials. The OSLT, OIT, optimal overall U-value, life-cycle cost (LCC), life-cycle saving (LCS) and payback period were calculated and compared between scenarios determined by this model and traditional model when the structural layer was known. The results indicate that the scenario determined by this model could achieve better energy-saving benefits. The payback period ranged from 2.25 to 5.07 years. The LCC saving rates and the growth ratio of life-cycle savings varied with these materials and heat sources from 0.55% to 3.70% and 0.19% to 1.40%, respectively. When same heat source being used, the total thicknesses of the structure and insulation layer (TTSIL) equals 300 mm, the order of achieved energy-saving benefits is XPS&gt;GW&gt;RW. The optimal overall U-value of the CIEW was independent of the required thickness of the structural and insulation layers and decreases with increasing unit heat consumption of heat sources. However, the energy efficiency revenue decreases with an increase in the TTSIL. The proposed method provides different proportions of thicknesses for construction walls and insulation layers, the variation of heat accumulation potential, influence on peak cooling/heating demand and environmental impact of the optimal CIEW will be studied in the future.

Optimum construction form and overall U-value of composite insulation external wall