Final Report: Testing the Viability of Agricultural Byproducts as a Replacement for Mineral Particles in a Novel, Low Embodied Energy, Construction MaterialEPA Contract Number: EPD09018
Title: Testing the Viability of Agricultural Byproducts as a Replacement for Mineral Particles in a Novel, Low Embodied Energy, Construction Material
Investigators: Hook, Susan Van
Small Business: Ecovative Design, LLC
EPA Contact: Richards, April
Project Period: February 1, 2009 through August 14, 2009
Project Amount: $70,000
RFA: Small Business Innovation Research (SBIR) - Phase I (2009) RFA Text | Recipients Lists
Research Category: SBIR - Green Buildings , Small Business Innovation Research (SBIR)
Sustainable Materials Revolution
Greensulate™ is a revolutionary replacement for petrol-derived materials, such as expand polystyrene (EPS), which are inherently unsustainable and rely on foreign resources. Outperforming conventional synthetics, Greensulate™ is a lightweight material that is literally grown and is comprised of abundant lignocellulosic waste bound using a filamentous fungus. Regional production reduces greenhouse gas emissions and energy consumption while taking advantage of domestic agricultural byproducts.
For the last 6 months, Ecovative Design, LLC has proven the economic viability and material performance of an insulating composite comprised of agricultural byproducts bound by a natural resin. Greensulate™ institutes the vegetative growth of a filamentous fungus, mycelium, which is a tenacious bonding agent that is grown in 7 days and surpasses the strength of EPS. The proposed research questions sought to optimize the growth rate of four basidiomycete species that can serve as the composite resin, quantify the thermal performance of each material compared to the synthetic competition, and determine the composting capabilities of each material. All studies were conducted to American Standards for Testing and Materials (ASTM) against controls of expanded polystyrene, which along with extruded polystyrene (XPS) constitute the largest market share in the rigid board insulation industry.
The growth or colonization rate of each fungus examined is crucial to reducing the incubation time and costs associated with inventory. Thus, the fungus with the fastest rate to completion is most ideal. The thermal performance characteristics, specifically thermal conductivity and fire retardance, are important to protect the home while decreasing energy consumption associated with heating ventilation and cooling. Finally, the composting analysis ensures that the material will passively degrade when in controlled environments, anaerobic digester and aerobic compost, and not within a building envelope. The results of these tests, coupled with research Ecovative Design accomplished outside of the scope of this contract, will inform the second phase of development required to commercialize Greensulate™ in a structural insulating panel.
According to an industry report compiled by Foresight Science and Technology, the rigid board insulation market is $6-7 billion annually in the United States and the structural insulating panel (SIP) industry represents 0.8 percent of this total. Presently, this construction system is dominated by petrol-foams, including EPS and expanded polyurethane, and a natural alternative does not exist for regional distribution. The SIP industry is an ideal market entry point for the Greensulate™ technology as this mode of construction is known for a tight building envelope, increased energy efficiency, and was quickly adopted by the environmentally conscious consumer. Furthermore, these structures benefit from Leadership in Energy and Environmental Design (LEED) certification, which has shown to increase real estate value. Greensulate™ qualifies for a number of LEED credits as the material is a rapid renewable, contains recycled content, and is produced regionally or within 500 miles of the end customer.
The Structural Insulating Panel Association (SIPA) selects the compliance tests and metrics that regulate the industry. Ecovative Design has presently met compliance or obtained results for most ASTM and International Building Code (IBC) tests required to install a construction material. Furthermore, the company is working with an international manufacturer and distributor of construction materials to develop new metrics in an effort to aid in commercialization. Concurrently, Ecovative Design continues to collaborate with SIP manufacturers in the Northeast, such as Timberline Panel LLC, to develop a superior product for their clientele that is more environmentally inert. Prior to introducing the material into the SIP market, there are still a number of structural, acoustical, and lifecycle properties in a panelized system that have to be quantified under building code compliance. These will be thoroughly examined under a Phase II workplan.
The Greensulate™ technology is inherently sustainable as the platform converts low-value waste streams into a high performance material via fungal biological conversion. Lignin is a primary constituent in plant waste and cannot be easily handled with industrial processes. Higher-level fungi, such as the white rot basidiomycetes implemented in the Greensulate™ process, breakdown the vast majority of the lignin found in nature due to the complex isoenzymes required to degrade the molecule. The process occurs in the dark, at room temperature and pressure, in as little as 5 days, which results in more than a 10 times reduction in energy consumed when compared to a thermal equivalent volume of EPS. Additionally, regional production reduces emissions associated with feedstock transport while creating a secondary revenue stream for rural economies. Construction waste constitutes approximately 60 percent of non-industrial waste generated annually and even though upwards of 30 percent of this material is recovered, the insulating materials are excluded due to difficulty in recycling. Greensulate™ offers an alternative to nonreusable rigid board insulators as Ecovative Design’s material can either be recycled to fabricate new material, aerobically composted, or anaerobically land-filled without detriment to the environment.
The anticipated launch for Greensulate™ rigid board insulation is in early 2011, after the final SIP compliance tests and customer metrics are met. With the results from all structural and thermal analyses, Ecovative Design has identified the protective packaging market as an entry point for the material. With the physical characteristics that outcompete expanded polystyrene at a lower cost, the Greensulate™ composite is an attractive alternative that allows Ecovative Design’s customers to promote green without reducing margins or losing protective efficacy. Entering this space initially, which generates over $2.3 billion annually in the United States, will allow the company to scale the production process and make initial sales while concurrently completing the development timeline for the construction material. Scaling the pilot production line to further accommodate larger materials, such as a 4 cubic foot insulation panel, would start in mid-2010 under an SBIR Phase II demonstration. Ecovative Design will be manufacturing more than 1000-2000 ft3/month of a packaging product throughout 2010 for a local window shade manufacturer. Comfortex sells several lines of energy efficient window shades and will be using molded end-caps comprised of Greensulate™ as soon as production is operational at scale. Additionally, the low thermal conductivity of composite is ideal for insulating shipping containers, which represent one of the fastest growing segments in packaging and there are no alternatives to EPS to meet this need. Finally, there are many other markets where Greensulate™ will have a significant impact. Upon completion of the compliance tests for sandwich panels, the composite can be adopted for other structural core applications, including everything from office furniture and lightweight vehicle panels to wind turbine blades and surfboard cores.
The first part of the study was focused on mycelia growth optimization of four basidiomycete species: Ganoderma applanatum, Ganoderma resinaceum, Pleurotus ostreatus, and Fomes fomentarius. The substrata were comprised of varying ratios of rice hulls, cottonseed hulls, trace carbohydrates, and mineral salts. The colonization rate of each fungus was quantified based on surface area growth on one of the six sides of each replicate growth enclosure. Growth was monitored over the course of 4 weeks and the results determined that G. resinaceum and P. ostreatus were the most rapid colonizers on the substrate that contained the highest concentration of cottonseed hulls.
The second part of the work plan examined the thermal characteristics of each of the 16 composites, particularly combustion (ASTM E1354) and thermal conductivity (ASTM C518). Two guarded hotplates were constructed, one at Ecovative Design and the other at Rensselaer Polytechnic Institute, to verify the thermal conductivity of each Greensulate™ specimen. The parts were tested in replicates of three against a control of expanded polystyrene. The resultant thermal conductivities ranged between 23.7- 40.9 percent less thermally resistive than the petrol-foam, with the G. resinaceum composite achieving the lowest conductivity. The Cone Calorimeter analysis was subcontracted to the Worcester Polytechnic Institute Fire Research Laboratory, and all 15 composites were tested under this study. The Cone Calorimeter serves as a baseline for the Room Corner Test (ASTM E84), which requires larger specimen sizes. The study analyzes the time to ignition under extreme temperatures and gases emitted during burning. All materials are anticipated to receive a Class 1 fire rating as the composites released small masses of smoke and exhibited endothermic properties. EPS could not achieve such a rating, so this makes Greensulate™ a safer choice in preventing fire proliferation in a home.
The last examination was the aerobic (ASTM D5338) and anaerobic (ASTM D5210) biodegradation characteristics of the top performing mycological composite from each set. Conducted under controlled conditions, the organic respiratory gases of microbes in the Greensulate™ composting vessels were measured daily and compared to controls of cellulose and polyethylene. All Greensulate™ composites other than F. fomentarius exhibited biodegradation in both aerobic and anaerobic settings; thus, construction waste can either be disposed of effectively in plant-based compost or in an anaerobic digester without a detrimental impact on the environment.
Several compliance tests were conducted on the Greensulate™ specimens outside of the scope of the contract and include both structural and moisture properties. G. resinaceum, G. applanatum, and F. fomentarius exhibit higher strength in flexure (ASTM C203) than expanded polystyrene as tested in a three point bend fixture on an Instron 4204. Based on growth rate, strength, and thermal properties, the Ganoderma resinaceum strain was selected for three common moisture studies: water vapor transmission rate (ASTM E96), water sorption under partial immersion (ASTM C1134), and fungal resistance (ASTM C1338). The vapor transmission study was contracted to the Composite Agency, and all three replicates of the rice hull-based composite received a Class 1 vapor retarder rating in accordance with the International Building Codes (0.03 Perm). The water sorption analysis was conducted at Ecovative Design and examined the water retention of rice hull-based Greensulate™ composites after 1 week of immersion in a water tank. The specimens tested retained structural integrity throughout the entire test and resulted in a density increase of a mere 7 percent. The fungal resistance study examined the material’s ability to inhibit the growth of five common household ascomycetes in comparison to a control of birch. Several specimens were tested with varying treatments, and the boride solution that is presently instituted in loose fill cellulose insulation was found to be the most effective in preventing mold propagation on Greensulate™.
Ecovative Design has constructed a prototype production line to handle larger volumes of raw materials with the capability of producing insulating panels with dimensions of 4’ by 4’ by 4”. Several panels have been grown and were installed in both residential and commercial applications in the American Northeast. During the construction and installation process, the panels were exposed to typical weather and handling conditions, all of which had a nondetrimental impact on the Greensulate™. Ecovative Design is continuing to produce large-scale insulating panels to meet the standards surrounding structural insulating panel construction. Upon successful completion of those and other customer-driven metrics, Ecovative Design anticipates the launch of Greensulate™ rigid board insulation in 2011.