Advanced Energy Design Guide LEED Strategies for Schools. and High Performance Buildings

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Hillary Scott
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1 Advanced Energy Design Guide LEED Strategies for Schools and High Performance Buildings

2 Today s Presenters Stephen Koontz, LEED AP Energy Services Leader Tampa Bay Trane Allen Irvine General Sales Manager Central & North Florida Trane Teri Borton Comprehensive Solutions Leader Gulf South Trane Tracy Henderson Account Manager Gulf South Trane 2

Central & North Florida Trane Teri Borton Comprehensive

3 What you will learn today... Resources Available to Assist with Designing Energy Efficient School & College Facilities HOW TO Tips Strategic Examples That Assist with 3

4 ADVANCED ENERGY DESIGN GUIDES Collaboration of: AIA ASHRAE CHPS IESNA NCEF SBIC USGBC U.S. DOE 4

5 Advanced Energy Design Guide for K-12 School Buildings al/systemportfolio.aspx 5

6 AEDG FOR K-12 SCHOOL BUILDINGS OVERVIEW Climate-specific recommendations to achieve 30% energy savings intended to show that achieving the 30% target is not only possible, but easy. Promotes off-the-shelf technology (no special expertise to design/install) Addresses whole building and the interaction of sub-systems (envelope, lighting, HVAC, service water heating) Eliminates need for energy modeling by providing prescriptive path to energy savings 6

Promotes off-the-shelf technology (no special expertise to design/install) Addresses whole building and the

7 LEED FOR SCHOOLS can be used to achieve four points under Energy and Atmosphere Credit 1 7

8 Chapter 3 Climate Zone Map 8

9 Chapter 3 Recommendation Tables 9

10 HVAC SYSTEMS 10

11 K-12 PRESCRIPTIVE HVAC RECOMMENDATIONS Which Type of HVAC System? Water-source Heat Pumps Unit Ventilators 4b Chilled-water VAV Small Packaged Rooftops 11

12 Prescriptive recommendations for Six HVAC System Types HV-1: Single-zone, packaged DX units (or split DX systems) HV-2: Water-source (or ground-source) heat pumps with dedicated OA system HV-3: Unit ventilators with water chiller and boiler HV-4: Fan coils with water chiller and boiler and dedicated OA system HV-5: Multiple-zone, VAV packaged DX rooftop units HV-6: Multiple-zone, VAV air handlers with water chiller 12

with water chiller and boiler HV-4: Fan coils with water chiller and boiler and dedicated OA system HV-5:

13 climate-specific and system-specific Recommendation Tables Unique recommendations are included for each HVAC system type in the climate-specific tables in Chapter 3 13

14 climate-specific and system-specific Recommendation Tables Some system types are not recommended for certain climate zones because of the impact of humidity on energy use 14

15 HV-1 Packaged (or Split) DX Units Climate Zone 2 15

16 HV-6 Chilled Water VAV Systems Climate Zone 2 16

17 Chapter 5 How To Tips Good design practice 17

18 Chapter 5 Good Design Practice Load calculations Dehumidification Energy recovery Equipment efficiencies Ventilation air Dedicated OA systems Economizer Demand ventilation Exhaust air systems Fan motor efficiencies System-level controls Chilled-water system Hot-water heating Thermal zoning Filters Duct design, construction Duct insulation Duct sealing, leak testing Air balancing Commissioning Relief versus return fans Heating sources Noise control Proper maintenance Zone temperature control Operable windows 18

Chilled-water system Hot-water heating Thermal zoning Filters Duct design, construction Duct insulation Duct sealing, leak

19 HV-10 HVAC Equipment Efficiencies Recommended efficiencies based on: Climate zone HVAC system type System size (capacity) Fuel type (electricity or natural gas) 19 for climate zone 5

20 HV-11 Ventilation Air Determine based on ASHRAE 62.1 Use actual occupancy for calculations, not exit population Use population diversity (D) when using multiple-zone recirculating systems Use time-of-day schedules to introduce ventilation air only when a zone is expected to be occupied 20

population diversity (D) when using multiple-zone recirculating systems

21 climate-specific and system-specific Recommendation Tables Because conditioning OA for ventilation is such a big contributor to energy use in schools, either exhaust air energy recovery or demand-controlled ventilation (DCV) is recommended. 21

22 HV-9 Exhaust-Air Energy Recovery 50% total effectiveness for A (humid) climate zones 50% sensible effectiveness for B (dry) climate zones Integrate control with airside economizer and provide bypass dampers 22

23 HV-14 Demand-Controlled Ventilation Vary amount of OA introduced by: Time-of-day schedule in BAS Occupancy sensor Carbon dioxide (CO 2 ) sensor Use in densely-occupied zones with highly-variable population Cafeteria Auditorium Conference Rooms Vary amount of exhaust air to prevent negative building pressure 23

24 HV-8 Part-Load Dehumidification Design system to minimize number of hours that space relative humidity remains above 60% Recommends methods for improving part-load dehumidification (by HVAC system type) For Chilled Water VAV System: 24

25 HV-12 Dedicated OA Systems 25

26 HV-25 Chilled-Water Systems Design for variable flow (except for very small systems) Use a chilled water T of F Low flow/low Temperature/High Delta T System 26

27 Proper Maintenance Neglecting preventive maintenance practices can quickly negate any energy savings expected Filters should be replaced regularly ERVs need to be cleaned periodically Dampers, valves, louvers, and sensors must all be periodically inspected and calibrated 27

28 Commissioning Selection of commissioning authority Include commissioning activities in the project schedule Recommended commissioning activities 28

29 Advanced Energy Design Guide for K-12 School Buildings al/systemportfolio.aspx 29

30 LEED Strategies 1. Capture and Reuse Condensate 2. Exhaust Air Energy Recovery 3. Thermal Energy Storage With Low temperature chilled water system 4. Scheduled and/or Demand Based Ventilation 5. Commissioning 30

31 CAPTURE and REUSE CONDENSATE OA S A to occupied space RA from occupied space 31

32 Capture and Reuse Condensate 15,000 CFM OA SA High School in Tampa, FL 1,000 Students 15 CFM/Person H ,000 Gallons 32

33 Capture and Reuse Condensate Cooling Tower Condensate Water is Cold Reuse Energy Condensate Water is Clean Lowers Chemical Treatment Replaces Potable Water for Cooling Tower Make-Up Wastewater Conveyance Irrigation 33

34 BENEFITS OF THERMAL ENERGY STORAGE Uses Off Peak Energy Rates Smaller Cooling Equipment- Less Refrigerant Reduce Power Plant Source Energy, Emissions and Need to Build Increase Operational Flexibility Achieves LEED Points by Reduce Energy Cost Over a Baseline Building ( E+A Up to 10 Possible Points) 34

35 TES COOLING LEED S TO RESULTS Conventional Design High School Hybrid Design High School 288,192 ft2 1,800 students 800 kw Peak Energy Star Rating 48 3 Watts / ft2 $120 / ft2 296,375 ft2 1,800 students 428 kw Peak Energy Star Rating Watts / ft2 $118 / ft2 $32,000 Less spent on Electricity

36 Seminole Community College 12/21/05-15 year Performance Contract $3.6 million Annual Guaranteed Savings $365, Tank Ice Storage Plant No Demand Charges Off-Peak energy rates Utility Rebate PROJECTS THAT WORK 36

37 Consider Thermal Energy storage if Utility has on-peak or off-peak rates (rebate) Peak load is higher than average load Peak demand is higher than average demand Existing system is being expanded Backup or redundant cooling is desired Cold air distribution is desirable (Lower humidity, smaller pipes, smaller ductwork) 37

38 Demand Control Ventilation OA relief air OSAU Control System OA VAV OA VAV lighting panel CO 2 CO 2 OS OS classroom classroom T T AHU RH VAV RH VAV RA 38 OSAU Outside Air Unit OA VAV- Outside Air VAV Box AHU Air Handling Unit RH VAV Reheat VAV Box

39 VAV Systems/ Demand Controlled Ventilation Benefits Include Reduces energy use Lowers operating cost Delivers appropriate amounts of fresh air Humidity control Healthier and more productive learning environment Improves occupant comfort, health, and productivity 39

40 Pensacola Junior College Installed Sensor Controlled Outside Air Ventilation For non-densely occupied spaces, use CO 2 sensors to signal system to provide appropriate amount of fresh air in classrooms Calibrate controls so that outside air damper modulates to maintain appropriate CO 2 levels Adjust fresh air intake to eliminate conditioning of excess outside air while ensuring a positive pressurized building Pensacola Junior College 40

41 Results VAV and Demand Control Ventilation strategies projected to save $142,000 annually 41

42 Fundamental Commissioning (Cx) Intent Verify energy related systems are installed and calibrated and operate according to: Requirements Owner s project requirements Basis of design/construction documents Minimum - HVAC and controls; lighting and daylighting controls; domestic hot water; and renewable energy (wind and solar) Encouraged - Water-using systems and building envelope Commissioning Authority (CxA) reports to Owner Benefits Include Reduced energy use Lower operating cost Reduced contractor call backs Improved occupant productivity and health Pre-requisite for LEED Certification 42

43 Retro-Commissioning of HVAC Systems Chipola College Campus consisted of 6 buildings with older generation building control system No commissioning of HVAC systems since original construction Utility price increase was forthcoming Decision made to re-commission HVAC systems to optimize energy usage 43

44 Strategy at Chipola College Activate controls software features and upgrade system to newest generation Time of Day programming eliminated 24/7 usage Unoccupied cooling and heating set points Optimal Start/Stop to reduce HVAC system run time Staggered start eliminating peak usage charges Modify building components to eliminate excess energy usage Adjusted Outside Air (OA) intake to eliminate conditioning excess OA while ensuring positive pressurized building Optimized chilled water bypass 44

45 Results $38,000 first month energy savings Sustained savings of $30,000-$40,000 monthly No increase in utility costs even with increased rates Improved comfort of students and staff 45

46 Hmmm. How can you afford NOT to? With budget cuts, we can t afford to install the highest efficiency HVAC and control systems for our new building. What is the true cost of ownership? 46

47 THANK YOU! 47

for K-12 School Buildings

Advanced Energy Design Guide for K-12 School Buildings HVAC Section John Murphy Applications Engineer, LEED AP Trane La Crosse, Wisconsin jmurphy@trane.com www.trane.com AEDG-K12 HVAC Subcommittee John