Grantee Research Project Results
Final Report: Accelerated Insulation Recycling System (AIRS)
EPA Grant Number: SU836788Title: Accelerated Insulation Recycling System (AIRS)
Investigators: Manoosingh, Celine
Institution: Georgia Southern University
EPA Project Officer: Page, Angela
Phase: I
Project Period: September 1, 2016 through August 31, 2017
Project Amount: $10,220
RFA: P3 Awards: A National Student Design Competition for Sustainability Focusing on People, Prosperity and the Planet (2016) RFA Text | Recipients Lists
Research Category: P3 Challenge Area - Sustainable and Healthy Communities , P3 Awards , Sustainable and Healthy Communities
Objective:
The technical challenge addressed by Phase 1 of this project is the curtailment of construction waste associated with disposal of current insulation technologies. A Design for Disassembly (DfD) approach is taken to address this challenge, and an alternative insulation system is developed and assessed. DfD is a design concept employed at the design stage for maximum material efficiency. It aims to provide flexibility in repair, refurbishment, and recycling.
Objective 1: Explore insulation design measures that will significantly reduce the amount of landfilled insulation waste, while improving or sustaining key metrics (i.e., structural strength, thermal conductivity).
Objective 2: Evaluate the design alternative in terms of environmental cost, effectiveness of thermal resistance, and efficiency of design for disassembly.
Objective 3: Suggest streamlined manufacturing and disassembly to ensure maximum material recovery and reuse. Insights gleaned from this analysis provide a viable and cost effective alternative to traditional foam insulation with complimenting assembly and disassembly processes for maximum material recovery.
Summary/Accomplishments (Outputs/Outcomes):
To address the DfD principle of architecture for structural support and disassembly, the team’s design comprised of a thin (2mm) recycled plastic hexagonal block as the nucleus of the design. Within the block is a compressed nucleus of organic byproduct. The selection and use of appropriate fasteners is an essential part of the DfD strategy, aimed at making material recovery as efficient as possible. To address this, each hexagonal piece comprises of grooves which serves as a mechanism to interconnecting pieces, which are designed to fit tightly to the other. The result is a honeycomb matrix of interlocking insulation blocks, providing both structural support and an effective way to quickly disassemble the structure for optimal material recovery.
The insulation system utilizes hexagonal blocks to form an insulation cartridge comprised of hexagonal cavities of size 5 inches. A triangular end piece also was developed to aid in sealing corner space. This corner space also was left open for wiring access should the configuration and design of the wall panel warrant such a measure. As is a key principle of DfD, reduction in traditional sealants in the panel structure significantly eases the separation process, and effectively enables material recovery. The fastener developed here involves snap-fit joints that fit securely and precisely to connect each interlocking block. This design allows for efficient assembly, and perhaps most importantly, rapid separation in order to salvage the material contained within and the block itself. The use of agricultural waste presented an excellent opportunity to involve the Statesboro farming community into a project that addressed the triple bottom line of sustainability. The materials utilized in this study were chosen because they are rich in lignin and cellulose, the main components of binder-less fiberboard. The project team found that when the cotton by-product is ground together and compressed with a small amount of sealant, the resultant material texture is similar to that of a sponge. A limitation to this design is the fact that cotton stalk has a high absorption capacity; to address this, a water resistance barrier was needed in function testing.
Several prototypes were created to determine the optimal design that would produce a prototype that was thermally and environmentally superior to traditional insulation. Three materials mixed with polyvinyl acetate and cement to create an appropriate binder were tested in in various concentrations. They included rice husk, cotton stalk, and cotton fibers. Adhesives were mixed and casted at 5%, 10%, 25% and 50% weight of cement to provide structural support. Thermal properties of the materials were tested with upper plate temperature of 80°F and lower plate temperature at 60°F. Test results of thermal resistance (mK/W) revealed that the average thermal resistance of the control mix or cement mix was 2.984 mK/W. Although waste cotton as a component has adequate thermal resistance, when mixed with the binder it failed to provide consistent results. Cotton stalk-cement and rice husk-cement composites provided higher thermal resistance, with thermal resistance consistently exceeding 118% of the control values. After thorough testing, rice husk-cement composites were selected for further detailed study of thermal and structural properties.
The developed structures are intended to use as non-load bearing or non-structural members, though reinforcement can be installed by casting holes for reinforcement bars into blocks. Structural compression testing of casted blocks provided an assessment of design strength. 4 x 8 cylinders were cast with 1%, 2.5%, 5%, 7.5% and 10% rice husk-cement composite and cotton-waste byproduct. The compressive strength of the material was examined according to ASTM C39/39M - 09a. Results were compared with the control and checked for the minimum required compressive strength for non-structural masonry units. Results indicated that cotton stalk mix in the percentage of 7.5% provided the optimal level of thermal insulation and structural support.
This cotton-stalk mixture was further assessed through a life cycle assessment. The research team used SimaPro v7.2, and built a cradle to grave model of the developed insulation, and traditional PU foam and fiberglass insulations, and then tested the underlying assumptions of the models. Data were drawn from a combination of literature review and SimaPro databases, including EcoInvent. Mid-point and end-point impact assessment methods were employed, including Impact 2002+ v.2.1 (Jolliet, et al., 2003). The life cycle assessment results revealed a 58% decrease in the environmental impact associated with non-renewable energy use when the cotton-stalk mix was compared to traditional PU foam. Also of note is that improved environmental metrics across four key categories: global warming, non-renewable energy, respiratory inorganics, and terrestrial acidification/nitrification was observed. The factor contributing most to the negative environmental impact associated with the insulation prototype was the use of the polyvinyl acetate binder, revealing the potential for prototype design improvement.
The processes of manufacturing and disassembly are critical parts of the design of this product. Employment of the DfD approach ensures that the production sequence eventually will lead to increased material recovery at the end of life of the unit. This is accomplished through employing precise and complimentary manufacturing and disassembly processes. To remove the insulation from the pre-fabricated wall, the fasteners connecting the wall should be removed first. After the panels are separated, the insulation system is separated. The staggered wall of insulated blocks can be taken apart readily because the fasteners used to bind them are interlocking snap and fit grooves. Once each block is taken apart, the cotton insulation nucleus can be recovered and separated from the recycled plastic shell by hand, enabled by the spongy nature of the material itself. The cotton insulation nucleus and the plastic shells both can be minimally reprocessed for reuse.
Conclusions:
The objective of this work was to develop an insulation system that was thermally, structurally, and environmentally efficient that employed DfD principles in order to attain maximum material recovery at the end of the product’s functional life. The design produced and evaluated by the P3 team achieved an improved thermal resistance of 18%, adequate structural properties for its application, and a 58% decrease in the environmental impact associated with non-renewable energy use when the cotton-stalk mix was compared to traditional PU foam. The complimenting assembly and disassembly processes ensure maximum material recovery at the end of the product’s functional life. Life cycle assessment results reveal that the design could be improved through the use of an alternative binder, to further reduce the associated environmental load.
During the course of the study period, the P3 team had significant interaction with farmers, industry experts, and K-12 students through ongoing outreach. The developed product was used as a centerpiece of innovation, and served as a tool to demonstrate DfD principles and life cycle thinking. As feedback was gathered from industry regarding the practicality of the design, the consistent theme gleaned was the inability to visualize the integration of this technology in construction. While the consulted industry experts were open and encouraging about the concepts of DfD, and the potential for its use, the identified barrier between research and practice was a lack of available tools to assist with new technology integration into current construction paradigms.
Journal Articles:
No journal articles submitted with this report: View all 2 publications for this projectSupplemental Keywords:
Sustainability in the built environment, design for disassembly, building insulation, life cycle assessmentRelevant Websites:
Georgia Southern University College of Engineering and Computing Exit Exit
The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.