Preparation and Characterization of a Type of Green Vacuum Insulation Panel Prepared with Straw Core Material.

Lu Wang,Yiyou Hong,Zhaofeng Chen,Zhou Chen,Jiankun Wu,Yong Yang

doi:10.3390/ma13204604

Abstract

The Vacuum Insulation Panel (VIP), regarded as the most promising high-performance thermal insulation material, still has application limitations because of its high cost. In this paper, VIPs using natural straw as the core material are prepared. The fiber saturation point (FSP) is important in order to determine the optimum for the use of renewable straw materials as a potential VIP core. The microstructure of straw core material, together with the relationship between the moisture content, the diametral compression strength, and the thermal conductivity of as-prepared straw VIPs are investigated. Compression characteristics of straw core material and heat insulation mechanism within the straw VIP envelope enclosure are analyzed. Total thermal conductivity of a straw VIP is sensitive to both the inner pressure and the moisture content of straw core material. The optimum drying process for straw VIPs is heating the straw core material at a temperature of 120 ℃ for 60 min, with its center-of-panel value being about 3.8 mW/(m·K).

Highlights

Vacuum insulation panels (VIPs) represent outstanding thermal insulation performance with a thermal resistance of about 10 times larger than that of thick conventional insulation materials and could make a great contribution to energy saving in buildings [1].A Vacuum Insulation Panel (VIP) is basically made of a micro-porous core structure which is evacuated and sealed in a thin, virtually gas-tight envelope bag [2]
A VIP is basically made of a micro-porous core structure which is evacuated and sealed in a thin, virtually gas-tight envelope bag [2]
The polystyrene (PS) foam, polyurethane (PU) foam and phenolic foam (PF) as the core materials were investigated in [4,5,6]. Powders have both high compression strength and thermal conductivity; insulation foams have been used since the early stage thanks to their low price; they have relatively poor insulation performance and large pore size, and fibers have good thermal resistance but poor structure stability [7,8]

Summary

Introduction

Vacuum insulation panels (VIPs) represent outstanding thermal insulation performance with a thermal resistance of about 10 times larger than that of thick conventional insulation materials and could make a great contribution to energy saving in buildings [1].A VIP is basically made of a micro-porous core structure which is evacuated and sealed in a thin, virtually gas-tight envelope bag [2]. Fricke et al stated that the core material had to be porous to evacuate and to have a minimum solid conduction effect. For this reason, bulk type materials in the form of powders, foams and fibers have been frequently used as the core material [3]. The polystyrene (PS) foam, polyurethane (PU) foam and phenolic foam (PF) as the core materials were investigated in [4,5,6] Powders have both high compression strength and thermal conductivity; insulation foams have been used since the early stage thanks to their low price; they have relatively poor insulation performance and large pore size, and fibers have good thermal resistance but poor structure stability [7,8]

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