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Ian Doebber Handout

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Gulf Coast Green Symposium 2009 - Speaker: Ian Doebber, Designing High Performance Schools in New Orleans.

Gulf Coast Green Symposium 2009 - Speaker: Ian Doebber, Designing High Performance Schools in New Orleans.

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  • 1. Designing High Performance Schools in New Orleans Gulf Coast Green Ian Doebber April 16, 2009 NREL is a national laboratory of the U.S. Department of Energy Office of Energy Efficiency and Renewable Energy operated by the Alliance for Sustainable Energy, LLC
  • 2. NREL Building Technologies Program NREL is a national lab for the US Department of Energy with a single mission to develop and promote renewable and energy efficiency technologies • Commercial & Residential Building Energy Efficiency • Technical Assistance to DOE’s EnergySmart Schools Program • Advanced Energy Design Guides • Computer Simulation Tool Development National Renewable Energy Laboratory Innovation for Our Energy Future
  • 3. Presentation Overview • K-12 Advanced Energy Design Guide • Rebuilding New Orleans Schools : Quick Start Schools • High Performance Schools in Humid Climates National Renewable Energy Laboratory Innovation for Our Energy Future
  • 4. K-12 Advanced Energy Design Guide Guidelines, based on climate zones, to help K-12 school owners and designers achieve 30% energy savings over ASHRAE 90 1 – 1999 90.1 • Recommendations only, not a code y, or standard • Applies to new construction and major renovation • Case studies showcase schools nationwide th t h ti id that have achieved or hi d exceeded 30% energy savings National Renewable Energy Laboratory Innovation for Our Energy Future
  • 5. Focus of Recommendations Building envelope – Fenestration – Wall/Roof Insulation Lighting systems – D li hti Daylighting – Electrical lights Heating, ventilation and air-conditioning ( g, g (HVAC) systems )y – Building automation and controls – Outside air (OA) treatment Service S i water heating (SWH) t h ti Guide looks at integration of these systems – savings goal dependent on the interaction National Renewable Energy Laboratory Innovation for Our Energy Future
  • 6. Where to get the K-12 AEDG? www.ashrae.org/freeaedg Download a copy at no charge -or- Purchase a print copy • 170,500 AEDGs have been downloaded or sold • 13,000 AEDG-K-12 hard cop es p o ded a d copies provided to every school district National Renewable Energy Laboratory Innovation for Our Energy Future
  • 7. Quick Start Schools Schematic Sh ti Construction Construction 2009 Opening RFQs Design Documents LEED for Schools Silver : 30% Utility Savings over AHSRAE 90.1 - 2004 y g Kick Off Design Charrette – Guided based on the K-12 AEDG Next 10 Years ~44 New Schools >40 Major Renovations National Renewable Energy Laboratory Innovation for Our Energy Future
  • 8. Quick Start Schools: Lighting Design ASHRAE 90.1 – 2004 PROPOSED LPD ZONE CATEGORY [W/ft2] OFFICE 1.0 1.4 1 4 W/ft2 CONFERENCE ROOM 1.0 10 GENERAL CLASSROOM 1.2 COMPUTER CLASSROOM 1.2 ART CLASSROOM 1.3 SCIENCE LAB 1.4 14 K-12 AEDG MEDIA CENTER 1.1 LOBBY/PREFUNCTION 0.8 AUDITORIUM n/a 1.1 11 W/ft2 MUSIC/THEATER/DANCE 1.4 14 GYM (play area) 1.2 GYM (spectator area) 1.2 FITNESS CENTER 0.8 Quick Start Schools LOCKER ROOMS 0.6 06 KITCHEN 1.1 0.8 – 0.9 W/ft2 WALKIN FREEZER D 0.4 WALKIN COOLER D 0.4 SERVERY 1.2 8% - 10% saving!! DINING AREA 0.7 CORRIDOR 0.5 National Renewable Energy Laboratory Innovation for Our Energy Future
  • 9. Quick Start Schools: Daylighting Design From AEDG Classroom Daylighting Recommendations National Renewable Energy Laboratory Innovation for Our Energy Future
  • 10. Quick Start Schools: Cooling Systems Main System OA Pre-Treatment Water Cooled Magnetic Bearing Desiccant Wheel Centrifugal Chiller Water Cooled Chilled Water High Efficiency Hi h Effi i Screw Chillers Enthalpy Wheels Air Cooled & Screw Chillers Packaged DX Units National Renewable Energy Laboratory Innovation for Our Energy Future
  • 11. Quick Start Schools: Savings Annual Utility Savings* Percent Savings $98,000 [$0.45/ft2] 26.2% $98,000 [$0.61/ft2] [ 30.5% $77,500 [$0.80/ft2] 35.1% *Based on Energy Model National Renewable Energy Laboratory Innovation for Our Energy Future
  • 12. Quick Start Schools: Lesson Learned Feedback to the next phase K-12 AEDG • More Aggressive Lighting Design o e gg ess e g g es g • Classroom Daylighting (Solving Glare-More Flexibility) • Demand Controlled Ventilation (System or Zone) • Insulation Levels (integrate with infiltration reduction) Major Short Coming was FOCUSING how following the K-12 th K 12 AEDG Recommendations REQUIRED a R d ti dedication to conquering Humidity otherwise forgo significant thermal comfort and energy performance National Renewable Energy Laboratory Innovation for Our Energy Future
  • 13. High Performance in Humid Climates Story of an Architect and Two Engineers… Previous Success : LEED Platinum on a High Rise Office Building in Phoenix, AZ Project Scope 100,000 ft2 K-5 Elementary School in New Orleans Conceptual Design thru Construction Administration LEED for Schools Silver Minimum of 23% Utility Savings over ASHRAE 90.1-2004 National Renewable Energy Laboratory Innovation for Our Energy Future
  • 14. Designing within Silos Maximized Daylighting M i i d D li h i Architect Silo 0.8 W/ft2 LPDbuilding [1.1 W/ft2 LPDclassroom ] High Performance Glazing Engineer 1 Silo Zone by Zone Humidistats Ventilation : ∑cfm/occ + ∑cfm/ft2 “Loads Based” Loads as Usual : 1.4 W/ft2 LPDclassroom 0.3 ACH Infiltration… Engineer 2 Silo High EER Roof Top Units High COP/IPLV Centrifugal Chiller “System B “S t Based” d” Premium M t P i Motors Efficient Centrifugal Airfoil Fans National Renewable Energy Laboratory Innovation for Our Energy Future
  • 15. Resultant School’s Performance Each Silo’s Design Focus was Implemented EXACTLY After a year of operation… operation Complaints of Cold, Damp Conditions Extremely High Utility Bills With 4 more schools under design, School District decided to form a Forensics Team National Renewable Energy Laboratory Innovation for Our Energy Future
  • 16. Building Forensics : Infiltration Problem : Increased Fenestration Details 1.0 to 1.5 ACH 0.3 ACH Can not rely on Building Pressurization! Remedy : Sealed Construction Details but too y expensive to fix vestibules National Renewable Energy Laboratory Innovation for Our Energy Future
  • 17. Building Forensics : Duct Leakage Looking at Testing and Balancing Report yielded ~30% Leakage Rate Remedy : Reduced to ~10% Leakage Rate by 10% improving to seal class B based on ASHRAE 90.1 following SMANCA Guidelines g National Renewable Energy Laboratory Innovation for Our Energy Future
  • 18. Building Forensics : RTU Sizing/Control Problem : Relying on Rules of Thumb and Lack of Communication Roof Top Units oversized and short cycling Direct Evaporative Cooling Remedy : Replaced with smaller Roof Top Units? Anyone else g any cheaper ideas? y got y National Renewable Energy Laboratory Innovation for Our Energy Future
  • 19. Building Forensics : Ventilation Problem : Misinterpretation of ASHRAE 62.1 Ventilation Rate Procedure for Multi-Zone Systems Ventilation =∑cfm/occ + ∑cfm/ft2 All Zones All Zones 50 ft2 / occ No Diversity 4 – 6 times actual school population Remedy : Calculated necessary Ventilation and reduced Outdoor Air Intake National Renewable Energy Laboratory Innovation for Our Energy Future
  • 20. Building Forensics : Reheat Dilemma Problem : Limitation of using only DX or Chilled Water Coils to provide both Cooling and Dehumidification When the supply air flow required to dehumidify the space exceeded the y p supply air flow required to meet 75ºF. Remedy 1 : Eli i t Zone by Zone Humidistats Eliminate Z bZ H idi t t R d Result 1 : Cold, Damp Conditions Remedy 2 : Do Nothing Result 2 : Significant Reheat yielding High Utility Bills National Renewable Energy Laboratory Innovation for Our Energy Future
  • 21. Psychometric Review 1 Properties of Air Temperature Moisture Content Relative Humidity mass of water Moisture Content = mass of dry air grains of water = pound of dry air d fd i National Renewable Energy Laboratory Innovation for Our Energy Future
  • 22. Psychometric Review 2 50% 100% Imagine 100% Relative Relative Relative Humidity Humidity y Humidity at these Temperatures 110 gr/lb 80 gr/lb 55 gr/lb 40 gr/lb 50ºF 40ºF 60ºF 70ºF National Renewable Energy Laboratory Innovation for Our Energy Future
  • 23. Conventional System Siamese Twins : Temperature & Moisture Content Temperature Fan Potential DX -or- Chilled 65 gr/lb Water Moisture 57 gr/lb Potential 75ºF 52ºF 55ºF National Renewable Energy Laboratory Innovation for Our Energy Future
  • 24. North Facing Classroom 1,000 ft2 Classroom Lights 31 occupants Off 1.4 1 4 W/ft2 Li hti Lighting No Plug 0.9 W/ft2 Plug Load Load 0.3 ACH Infiltration R-13 Walls / 0.5 SHGC 0.4% Design Day Conditions (Sunny) Cl d Cloudy Space Air = 75ºF & 65 gr/lb Supply Air = 55ºF & 57 gr/lb pp y g 500 cfm Thermal Load Requires = 1,000 cfm Moisture Load Requires = 850 cfm
  • 25. Psychometric Chart Cold and Damp are the Worst Conditions in Regarding Reheat g g 65 gr/lb 75ºF National Renewable Energy Laboratory Innovation for Our Energy Future
  • 26. Technologies to Battle Humidity Following Systems provide E F ll i S t id Energy Effi i t way t Efficient to Supply Air at HIGHER Temperature (55ºF to 65ºF) but LOWER Moisture Content (57 gr/lb to 53 gr/lb) 1. Hot Gas Reheat 2. Heat Pipe or Sensible Wheel 3. Desiccant Wheels 4. Enthalpy Wheels 5. Combination of all of the above
  • 27. Hot Gas Reheat DX Hot Gas 65 gr/lb /lb 53 gr/lb 50ºF 75ºF 65ºF National Renewable Energy Laboratory Innovation for Our Energy Future
  • 28. Heat Pipe or Sensible Wheel Heat Pipe H t Pi or Sensible Wheel Exhaust Air DX 65 gr/lb /lb -or- Chilled 53 gr/lb Water 50ºF 75ºF 65ºF National Renewable Energy Laboratory Innovation for Our Energy Future
  • 29. Desiccant Wheels Hot Gas DX 65 gr/lb /lb 53 gr/lb 57ºF 75ºF 65ºF National Renewable Energy Laboratory Innovation for Our Energy Future
  • 30. Enthalpy Wheels - Regenerative Braking Most Cost Effective Means of Dehumidification Exhaust Air DX Hot 65 gr/lb /lb Gas 53 gr/lb 75ºF 65ºF 50ºF National Renewable Energy Laboratory Innovation for Our Energy Future
  • 31. Enthalpy Wheel & Heat Pipe Heat Pipe or Sensible Wheel Exhaust Air DX -or- or 65 gr/lb /lb Chilled 53 gr/lb Water 75ºF 65ºF 50ºF National Renewable Energy Laboratory Innovation for Our Energy Future
  • 32. Dedicated Outdoor Air System (DOAS) Trifecta D T if t Decouple l 1. Moisture - Centralized System that provides “Dry” (~50 gr/lb) Outdoor Air between 55ºF 75ºF (~65ºF) 55ºF-75ºF 2. Temperature – L 2T Local F C il U it or W t S l Fan Coil Units Water Source t Heat Pumps to maintain 75ºF setpoint 3. Ventilation – Dampers on 100% Outdoor Air Supply controlled by Zone CO2 sensor K-12 AEDG National Renewable Energy Laboratory Innovation for Our Energy Future
  • 33. What Happened to our Design Team 1. Used the K-12 AEDG as a starting point : -Lighting Design g g g -Daylighting Design -Envelope Design -Started the Discussion of Mechanical S t St t d th Di i f M h i l Systems EARLY in Conceptual Design 2. Focused on how to conquer humidity by balancing Energy Efficient Dehumidification while minimizing gy g Reheat National Renewable Energy Laboratory Innovation for Our Energy Future
  • 34. Architects Review Infiltration : Focus on Construction Details and Vestibule Design to minimize Infiltration Access to Exhaust Air : Coordinate room layout to provide access to Exhaust Air Coordinate Space Requirements : Equipment using Desiccant or Enthalpy Wheels often need double height space py g p Reference : “ASHRAE Humidity Control Design Guide” ASHRAE Guide National Renewable Energy Laboratory Innovation for Our Energy Future
  • 35. Engineer Duct Leakage : at least leakage class B Ventilation : Understand ASHRAE 62.1 Ventilation 62 1 Requirements but do not need to Over Ventilate Start the Mechanical Conversation EARLY : Work with the rest of the Design Team in Conceptual or Schematic Design to determine the Optimal System Energy Efficiency Dehumidification without Comprimising Reheat READ “ASHRAE Humidity Control Design Guide” National Renewable Energy Laboratory Innovation for Our Energy Future