Session: Track 2 Energy Technology Session 4 Phase Change Material for Building Envelope Reyad Sawafta, Ph.D. Chief Scientific Officer Phase Change Energy Solutions www.phasechange.com Rhode Island Convention Center Providence, Rhode Island
US Buildings In the US, the commercial real Estate Market 84 billion ft 2 total 7 billion ft 2 retail 70,000 bank branches 380,000 mobile buildings and many other types 41% of the total U.S energy is consumed by the residential and commercial building sectors ( Monthly Energy Review 2016). Heating and cooling requirements alone account for 58% of that value (Annual Energy, 2016) Some targets cannot be met with the existing materials. 2
Demand for Energy Savings Architects, designers, engineers and owners are demanding additional energy savings and enhanced comfort. Lower HVAC expense Lower peak (high $$$) electricity demand Consistent, comfortable temperature even during peak loads Reasonable Up-Front Cost and Rapid ROI Long lifetime and low / no maintenance Sustainable Resilience Phase Change Materials (PCMs) for thermal regulation and thermal energy storage in buildings provides an elegant solution for more efficient energy use. 3
Phase Change Materials (PCMs) at Work 144 BTU/ lb 4
Phase Change Materials (PCMs) PCMs to be used for latent heat storage should: 1. Have a melting point which matches the application, 2. Have a high value of heat of fusion and specific heat per unit volume and weight, 3. Have a low vapor pressure at the operational temperature, 4. Have a chemical stability and non-corrosiveness, 5. Not be hazardous, highly inflammable or poisonous, 6. Have a reproducible crystallization without degradation, 7. Have a small super-cooling degree and high rate of crystal growth, 8. Have a small volume variation during solidification, 9. Have a tunable thermal conductivity, 10. Be of abundant supply and at a low cost.
How PCMs Work? PCMs are solid at room temperature, as the temperature becomes warmer they liquefy or become a gel, absorb and store heat, and when the temperature drops they solidify and give off heat. Ambient Hotter Than Set Point Ambient Colder Than Set Point 90-120 BTU / lb. Simply, PCMs operate like a thermal sponge to help maintain Temperature at the designed set point (i.e. 70 or 73 or 77ºF or any desired temperature ). Energy Exchange: Federal Sustainability 6 for the Next Decade
Phase Change Materials (PCMs) PCMs have a higher heat storage capacity than conventional thermal mass, and provides excellent heat transfer. It demands no extra structural support and any added installation cost is minimal. Because the exposed surface in building products is so large and the PCMs absorb heat over a narrow temperature range, the building products need not receive direct sunlight.
Phase Change Materials (PCMs) PCMs can smooth daily fluctuations in room temperature by lowering the peak temperatures resulting from extreme external daily temperature changes. Two identical buildings tested in Asheboro, NC Both buildings had standard fiberglass insulation One with ENRG Blanket TM, the other used as control
Phase Change Materials (PCMs) PCMs reduce home heating or cooling loads, thereby producing energy savings for the consumer by as much as 20-40% depending on climate. PCMs are not binary systems In a mechanically controlled building 8-12 air changes per hour PCMs go through many partial transitions that can total 3-7 full transitions resulting to 300-840 BTUs/lb.
Bio-based PCMs can be used to reduce Internal Load 10
Commercial Office 8:00 AM Office Space ready for a new day 11
Commercial Office Business Hours Heat load from numerous sources absorbed by BioPCM 12
Commercial Office Nighttime Heat load being released by BioPCM to nighttime air 13
Mechanically Controlled Space Cooling Tstat Setpoint is @ ~70-73ºF When an HVAC system is in cooling mode the temperature of the cool air coming from the air registers is ~55F. 14
Mechanically Controlled Space Heating Tstat Setpoint is @~68-70ºF When an HVAC system is in heating mode the temperature of the warm air coming from the air registers is ~90ºF 15
Phase Change Materials (PCMs) Commonly used PCMs are: 1. Plant and Bio Based 2. Salt hydrates 3. Paraffin and paraffin waxes 4. Polymers 5. Metals
Salt Hydrates The main limitations of salt hydrates are: 1. They absorb moisture, which decreases their effectiveness, 2. They are unstable, following dehydration in the process of thermal cycling; losing some water content every heating cycle. 3. Some are chemically aggressive towards structural materials 4. They have a low heat conductivity 5. They have a relatively high degree of supercooling 6. They require costly and impractical encapsulation with a semi-impermeable coating for improved performance.
Paraffins 1. Paraffins are waxes 2. They are readily available 3. They melt at different temperatures relating to their carbon-chain length, so they have a wide range of the phase change temperatures 4. They have a low heat conductivity 5. They are based on Petroleum and flammable 6. Toxic and Not Readily Biodegradable
Bio-Based Phase Change Materials Among organic materials, fatty acids and their derivatives are attractive for the following reasons: 1. Readily available and cost effective. 2. Renewable: they come from vegetable oils and their by-products. 3. Widely used in different areas such as food, medicine, cosmetics, shipping and others. 4. Melting temperature varies from 50 to 150 C 5. Latent heat of fusion varies from 150-250 kj/kg 6. Non-Toxic and Readily Biodegradable
Phase Change Material Types Environment Impact Energy Density (BTU/lb) Lifetime (years) Cost of Production ($/sq ft) Supercooling Volume Change Corrosive Flammable BioPCM Paraffin Salt Hydrates Positive Negative
Company Background Established in 2008 75K ft 2 manufacturing facility in Asheboro, NC Focused on Reducing HVAC Energy Consumption for Commercial, Industrial, and Government Customers More than 1M ft 2 deployed World Wide Patents: Formulation Applications Solar Powered HQ and Manufacturing Facility 21
Bio-based PCM Installation Interior: Ceiling, Wall & Floor Exterior: Roof & Wall Retrofit or New Build Straightforward Installation: Install 1,000 ft 2 per hour with 2 ladders and 4 person crew! 22
JP Morgan Chase Bank - Retrofit LOCATION: Elmhurst, NY 2000 Sq. Ft. of BioPCM installed Covering 70% of the surface area above the ceiling tiles No disruption to normal operations 23
JP Morgan Chase Bank - Retrofit LOCATION: Elmhurst, NY Financial Summary - First Year Results Daily kwh Reduction..109* kwh Cost..$.1847 Daily Savings...$20.13 Annual Savings...$7,347 Cost of BioPCM @ $4.69 Sq. Ft.**..$9,380 Payback BioPCM...1.28 Yr. * Independent Testing: Noveda Technologies 24
U of Washington New Construction LOCATION: Seattle, WA Construction in 2012 Building uses BioPCM for passive cooling 98% HVAC Energy Savings 25
Easton Archery Center LOCATION: Chula Vista, CA Expected ROI <12 months (cost avoidance on HVAC plus energy usage reductions) 43,800 ft 2 BioPCM installation Bob Easton Architect, Kiewit Corporation 26
Fort Irwin - California A multi-solution approach including BioPCMs was used in 20 buildings at Fort Irwin Initial Results showed 37% energy reduction Continuous data collection through a 12-month M&V cycle is ongoing to demonstrate the effect in different seasons and to quantify different component contributions. 27
PhaseStor Case Study- Scope Description Provide thermal storage to support server room cooling in event of loss of power Provide minimum 15 mins at approx. 58 F Provide equivalency of 87,000 Btu (14.5 tons) of cooling Chiller to charge PCM -45 F PCM freeze temperature set -49 F Chilled water return temperature from server room to inlet of BioTess average 68 F Chilled water outlet temperature leaving BioTess to server room - average 58 F Average Δ10 F 28
Phase Change Energy Solutions Huge demand for further energy savings Commercial, Industrial, Government Target market is billions of ft 2 Bio-based PCM can complement insulation to create additional HVAC energy savings of 20% to 40% ROI estimated to be between 1 to 5 years without tax credits or other government incentives Effectiveness and ROI have been demonstrated with marquis customers 29
Questions? Phase Change Energy Solutions 120 E. Pritchard St. Asheboro, NC 27203 1-800-283-7887 www.phasechange.com 30