Advanced Energy Design. How to Use the Guide and

Transcription

1 Advanced Energy Design Guide for K-12 Schools How to Use the Guide and Key Technology Discussion

2 Section 1 INTRODUCTION Slide 2

3 Goals of the Advanced Energy Design Guide for K-12 School Buildings Help schools make smart investments t in energy savings so that more funds can be channeled to education Illustrate how to build a school that uses 30% less energy than the standard Working toward net zero energy schools that produce as much energy as they use Section 1: Introduction Slide 3

4 What is the Advanced Energy Design Guide (AEDG)? Guidelines, based on climate zones, to help K-12 school owners and designers achieve 30% energy savings over baseline standard Recommendations only, not a code or standard Applies to new construction and renovation Specific implementation tips Case studies showcase schools nationwide that have achieved or exceeded 30% efficiency gains Section 1: Introduction Slide 4

5 AEDGs For Other Buildings Advanced Energy Design Guides available to date Small Office Buildings Office buildings up to 20,000 ft 2 Small Retail Buildings Retail spaces up to 20,000 ft 2 K-12 School Buildings Elementary, Middle, and High School Small Warehouses and Self- Storage Buildings Warehouses up to 50,000 ft 2 Self-storage with unitary heating and air-conditioning Section 1: Introduction Slide 5

6 Guide Development U.S. Department of Energy American Society of Heating, Refrigerating and Air-Conditioning Engineers American Institute of Architects Illuminating Engineering Society of North America U.S. Green Building Council Sustainable Building Industry Council National Clearinghouse for Educational Facilities Collaborative for High Performance Schools Section 1: Introduction Slide 6

7 Audience of the K-12 AEDG School boards, school administrators, school facility managers to use in new construction and major renovation Contractors, architects, engineers, designers who design, build, and renovate schools Special note on renovation In general, can t address siting, window sizes, major structural t Can address some envelope, HVAC, lighting Section 1: Introduction Slide 7

8 Benefit of the K-12 AEDG All of the suggestions bundled in one simple guide Easy-to-follow recommendations by climate zone How-to tips for easy implementation Recommends products that are off-the shelf and readily available Case studies illustrate t real-life lif advanced d energy approaches Additional bonus strategies for savings beyond 30% A prescriptive path for LEED energy efficiency credits Section 1: Introduction Slide 8

9 Benefits of an Energy-Efficient School More efficient school building Lower construction costs Lower operating costs especially in the future as energy costs continue to rise Lower environmental impact Water Greenhouse gasses Conserve materials and resources Section 1: Introduction Slide 9

10 Benefits of an Energy-Efficient School Better learning environment Higher quality lighting More comfortable conditions improved productivity in students and staff Improved student attendance Use as a teaching opportunity Build curriculum around this Help generate interest and create tomorrow s work force in sustainable fields Section 1: Introduction Slide 10

11 Where to Get the K-12 AEDG Visit Download a copy at no charge Purchase a print copy Section 1: Introduction Slide 11

12 Section 2 MORE ON ENERGY SAVINGS Slide 12

13 Helping with Energy Savings Present some ways to build schools that use significantly less energy than those built to the minimum energy efficiency code Not all of the ways or the only way Climate specific Not a code or standard Package results in at least 30% savings above the minimum requirements of ANSI/ASHRAE/IESNA Standard Pre-computed set of solutions to make it easier to implement Based on site energy use and typical plug loads Section 2: More on Energy Savings Slide 13

14 AEDG and LEED - Prescriptive Compliance Path 4 credits for V2.2, 1 for LEED 2009 No energy modeling required Comply with all of the prescriptive measures for the climate zone and follow the checklist The following restrictions apply Buildings must be under 100,000 ft 2 Buildings must include the typical spaces covered under the scope Section 2: More on Energy Savings Slide 14

15 AEDG and LEED - Whole Building Energy Simulation Modeling will further optimize the design to improve energy performance and reduce up-front costs Pick one of the following two paths 1. Daylighting Without high efficiency electric lighting Energy savings is 30-45% over LEED points would be No daylighting With high efficiency electric lighting Energy savings is 24-41% over LEED points would be 5-9 Section 2: More on Energy Savings Slide 15

16 Determining the Recommendations Computer modeling and simulation Focus group for conceptual review Recommendations developed by school designers Extensive peer review Modeling based on Elementary 74,500 ft 2 Middle School 112,000 ft 2 High School 205,000 ft 2 Section 2: More on Energy Savings Slide 16

17 Baseline Models Elementary Baseline Middle Baseline High Baseline Slide 17

18 Modeling Process Computer simulation compared options with baseline for all climate zones 44% 41% 41% 140 Interior Equipment Exterior Lighting Interior Lighting Cooling Fans Pumps 120 Heating Water Systems Savings 43% 45% 45% % 41% 42% 40% 40% 40% 39% 38% 40% 80 38% 37% 39% 36% 37% 39% 38% 41% 39% 42% 41% 45% 37% 37% 43% 34% 35% 36% 35% 36% 38% Slide 18 35% 33% 37% 39% 37% 38% 35% 35% 38% 60 Site EUI (kbtu/ft 2 ) % - Daylit PVAV 30% - Daylit VAV 30% - Daylit PSZ Baseline 30% - Daylit PVAV 30% - Daylit VAV 30% - Daylit PSZ Baseline 30% - Daylit PVAV 30% - Daylit VAV 30% - Daylit PSZ Baseline 30% - Daylit PVAV 30% - Daylit VAV 30% - Daylit PSZ Baseline 30% - Daylit PVAV 30% - Daylit VAV 30% - Daylit PSZ Baseline 30% - Daylit PVAV 30% - Daylit VAV 30% - Daylit PSZ Baseline 30% - Daylit PVAV 30% - Daylit VAV 30% - Daylit PSZ Baseline 30% - Daylit PVAV 30% - Daylit VAV 30% - Daylit PSZ Baseline 30% - Daylit PVAV 30% - Daylit VAV 30% - Daylit PSZ Baseline 30% - Daylit PVAV 30% - Daylit VAV 30% - Daylit PSZ Baseline 30% - Daylit PVAV 30% - Daylit VAV 30% - Daylit PSZ Baseline 30% - Daylit PVAV 30% - Daylit VAV 30% - Daylit PSZ Baseline 30% - Daylit PVAV 30% - Daylit VAV 30% - Daylit PSZ Baseline 30% - Daylit PVAV 30% - Daylit VAV 30% - Daylit PSZ Baseline 30% - Daylit PVAV 30% - Daylit VAV 30% - Daylit PSZ Baseline 2A 2B 3A 3B 3C 4A 4B 4C 5A 5B 6A 6B 7A 8A 1A Section 2: More on Energy Savings

19 Section 3 OVERVIEW OF PROCESS 19

20 Key Steps in Construction Process Assemble the Right Team Hold a Design Charrette and Set Goals Follow Key Steps of Integrated Design Ensure Monitoring and Maintenance Section 3: Overview of Process Slide 20

21 Assemble the Right Team School administrators and maintenance staff Owners representative or consultant managing the project Designer Architect Contractors t Engineers (HVAC, plumbing, mechanical, sound) Lighting designer Landscaper Commissioning authority Section 3: Overview of Process Slide 21

22 Hold a Design Charrette and Set Goals Read chapter 2 of the AEDG An Integrated Design Approach to Achieve Savings Entire team participate in a workshop or brainstorming session, to generate ideas among stakeholders Set measureable and specific goals Start with 30% AEDG as a baseline Set additional energy goals to achieve improved savings Use performance metrics and case studies Understand uses and occupancy rates of each space Determine goals based on actual measurements like lighting power density in watts per square foot Consider using modeling tools Section 3: Overview of Process Slide 22

23 Follow Key Steps in Integrated Design 1. Choose a site to maximize benefit of natural resources, especially daylighting Elongate east-west axis Maximize north-south facing classrooms 2. Decide on daylighting or electrical l lighting strategy t Plan to daylight unless site issues saves lighting energy and reduces cooling loads Hire consultant early to design windows, overhangs, interior finishes, other daylighting elements Section 3: Overview of Process Slide 23

24 Follow Key Steps in Integrated Design 3. Reduce loads Good envelope Windows Walls Manage plug loads Overhangs Roof 4. Size systems properly for reduced loads Incorporate efficient equipment and systems Design lighting to complement daylighting 5. Commission systems to ensure integration Look for this symbol to highlight recommendations that are best considered early in the design process Section 3: Overview of Process Slide 24

25 Ensure Monitoring and Maintenance Commission to make sure building works After construction and on-going Train school personnel Meter and evaluate Section 3: Overview of Process Slide 25

26 Section 4 USING THE K-12 AEDG 26

27 Spaces Addressed Space Types Addressed Classrooms Administrative Corridors Restrooms Gyms Assembly Kitchen Media Centers Space Types Not Covered Pools Wet Labs Wood working or Auto shop Field Lighting Section 4: Using the AEDG 27

28 Focus of Recommendations Building envelope Fenestration Lighting systems (electrical lights and daylighting) Heating, ventilation and air-conditioning (HVAC) systems Building automation and controls Outside air (OA) treatment t t Service water heating (SWH) Guide looks at integration of these systems savings goal dependent on the interaction Section 4: Using the AEDG Slide 28

29 Steps to Use the Guide Chapter 1: Foreword to School Board and Administrators Chapter 2: Read this chapter on Integrated Design first Chapter 3: Find your climate zone and carefully review the recommendation table Chapter 4: Review the case study for your climate Chapter 5: Follow tips to implement recommendations found in chapter 3 Section 4: Using the AEDG Slide 29

30 Chapter 3 Recommendations by Climate Section 4: Using the AEDG Slide 30

31 Chapter 3 - Recommendation Table Section 4: Using the AEDG Slide 31

32 Chapter 4 Case Studies Whole Building Case Studies by Climate Zone Side Bar Technology Case Studies Zone 1 - Waipahu Intermediate School Cafeteria Waipahu, Hawaii Zone 2 - Desert Edge High School Goodyear, Arizona Zone 3 Homewood Middle School Homewood, Alabama Zone 4 Knightdale High School Knightdale, North Carolina Zone 4 Third Creek Elementary School Statesville, North Carolina Zone 5 Bolingbrook High School Bolingbrook, Illinois Zone 5 - Whitman-Hanson Regional High School Whitman, Massachusetts Zone 6 Westwood Elementary School Zimmerman, Minnesota Zone 6 - Alder Creek Middle School Truckee, California Zone 7 Silverthorne Elementary School Silverthorne, Colorado Section 4: Using the AEDG Zone 4 - R.D. & Euzelle P. Smith Middle School Chapel Hill, North Carolina Zone 4 - Twenhofel Middle School Independence, Kentucky Zone 4 - Salem Middle School Apex, North Carolina Zone 4 - Elmira High School Elmira, Oregon Zone 5 - The Dalles Middle School The Dalles, Oregon Zone 5 - Zach Elementary School Fort Collins, Colorado Slide 32

33 Chapter 5 How to Implement Recommendations Provide good design practices, cautions, references Commissioning (CX) HVAC (HV) Envelope (EN) Service Water Heating (WH) Electric Lighting (EL) Additional Savings (AS) Daylighting (DL) Not needed for 30% - provide energy savings beyond 30% Exterior Lighting (EX) Refer to this as you go through climate specific recommendations numerically Section 4: Using the AEDG Slide 33

34 Chapter 3 - Recommendation Table Section 4: Using the AEDG Slide 34

35 Section 5 BUILDING ENVELOPE RECOMMENDATIONS 35

36 Getting the Envelope Right Least expensive and simplest upgrades during the design phase Very expensive (if even possible) to fix after construction Get energy efficiency gains with least maintenance Insulation recommendations for Walls Windows Roofs Doors Slabs Section 5: Building Envelope Recommendations Slide 36

37 Tips for Entire Envelope Detail to minimize Thermal Breaks EN15: Alternative Constructions OK if less than or equal to the U-factor for the appropriate climate zone Appendix A offers U-factors, C-factors, and F-factors that t correspond to all the recommendations EN18: Continuous Air Barrier System Control air leakage between spaces with different conditioning EN2 through EN12: Insulation R Value R-value of cavity insulation (not including framing) continuous insulation (ci) for mass walls, built up roofs R-19 +R-19 ci Section 5: Building Envelope Recommendations Slide 37

38 Summary of Roof Recommendations Recommended R values for roofs based on climate zones and how they compare to standards Temperate and warmer zone less roof insulation Less roof heat loss More heat gain through windows Colder zones need higher level roof insulation Section 5: Building Envelope Recommendations Slide 38

39 EN1: Cool Roofs Climate zones 1,2,3 use cool roof with solar reflectance index (SRI) of 78+ Section 5: Building Envelope Recommendations Slide 39

40 EN2: Roofs, Insulation Entirely Above Deck Insulation entirely above deck should be continuous insulation (c.i.) rigid boards No framing members to introduce thermal bridges (a) (b) (c) Insulation is installed above (a) Concrete (b) Metal (c) Wood deck in a continuous manner. Section 5: Building Envelope Recommendations Slide 40

41 EN3: Roofs, Attics, and Other Roofs Ventilated attics insulation at ceiling line Unventilated attics insulation at roof line Metal/standing seam roof minimize thermal bridging (a) Ventilated attics (b) Unventilated attics (a) (b) Prefabricated metal roofs showing thermal blocking of purlins (a) (b) (c) Section 5: Building Envelope Recommendations Slide 41

42 EN4: Roofs, Single Rafter Cavity insulation installed between rafters and in contact with the ceiling Section 5: Building Envelope Recommendations Slide 42

43 Summary of Wall Recommendations Recommended R values for walls based on climate zones and how they compare to standards Section 5: Building Envelope Recommendations Slide 43

44 EN5: Walls, Mass Benefits of mass walls Greatest advantage of mass when insulation placed on its exterior Mass absorbs heat from the interior spaces which is released when the buildings are not occupied Reduces the magnitude of indoor air temperature swings and improves thermal comfort (a) C.i. on exterior (b) Furring or framing on interior (a) (b) Section 5: Building Envelope Recommendations Slide 44

45 EN6 & EN7: Walls, Steel and Wood Framed EN6: Walls, Steel Framed EN7: Walls, Wood Frame Section 5: Building Envelope Recommendations Slide 45

46 EN8: Below Grade Walls (a) (b) (c) (a) rigid c.i. recommended on exterior of wall (b) furring or (c) framing system is recommended on the interior Section 5: Building Envelope Recommendations Slide 46

47 Summary of Floor Recommendations Recommended R values for floor insulation based on climate zones and how they compare to standards Section 5: Building Envelope Recommendations Slide 47

48 EN9 & EN10: Floors, Mass and Steel Joist or Wood Frame (a) (b) EN9: Floors, Mass (a) High-density extruded polystyrene as c.i. above the slab with either plywood or a thin layer of concrete on top (b) Insulation placed below the deck EN10: Floors, Steel Joist, or Wood Frame Section 5: Building Envelope Recommendations Slide 48

49 Summary of Slab Recommendations Recommended R values and length in inches for slab insulation based on climate zones and how they compare to standards d i.e. In Climate Zone 6 for an unheated slab, AEDG recommends R-10 for 24 at the perimeter EN11 & EN12: Slab, Unheated & Heated In Climate Zones 6-8 c.i. should be placed beneath the full slab Section 5: Building Envelope Recommendations Slide 49

50 EN11 & EN12: Slab-on-Grade Floors, Unheated and Heated EN11: Slab-on-Grade Floors Unheated (a) Rigid c.i. around perimeter of slab to the recommended depth or to the bottom of the footing (b) If frost line is deeper than the footing, place c.i. beneath the slab as well (a) (b) EN12: Slab-on-Grade Floors Heated Slab-on-grade floors, heated heating elements either within (as shown) or below the slab Section 5: Building Envelope Recommendations Slide 50

51 Summary of Door Recommendations Recommended U factors for doors based on climate zones and how they compare to standards. EN13: Doors-Opaque, Swinging Try to use single swinging doors Double swinging doors are difficult to seal at the center of the doors unless there is a center post Vestibules help in cold climates Section 5: Building Envelope Recommendations Slide 51

52 Summary of Fenestration Recommendations Recommended values for slab fenestration based on climate zones and how they compare to standards. Location of fenestration driven by use of daylighting and building layout on the site High visible transmittance for daylighting glazing Section 5: Building Envelope Recommendations Slide 52

53 Vertical Fenestration Descriptions Visible Light Transmission (VLT) VLT is an important aspect of daylighting Windows with higher VLT and lower SHGC can allow light transmission and minimize heat gain For daylighting glazing, VLT > 65% Section 5: Building Envelope Recommendations Slide 53

54 EN19: Vertical Fenestration Descriptions U-factors for windows measured over entire assembly including glass, sash, and frame (not center of glass) Projection factor Ratio of the horizontal depth of the overhang divided by the height above the window sill Use the SHGC multipliers for vertical fenestration with overhangs to meet the high visible transmittance recommendations needed for daylighting Section 5: Building Envelope Recommendations Slide 54

55 EN20: Fenestration to Gross Wall Area Ratio Fenestration to gross wall area should not exceed 35% Includes daylighting and view glass Minimize east and west glass Total fenestration area is the rough opening and including the glazing, sash, and frame See AEDG for details on definitions Section 5: Building Envelope Recommendations Slide 55

56 EN23 and EN26: Site Selection and Window Orientation Warm climates (1-4) Elongate building east-west and orient more windows to the north and south Avoid windows that don t contribute to view or daylighting Minimize solar penetration through east-and west-facing glazing Cold climates (5-8) Elongate building east-west and maximize south-facing windows for view and daylighting Control glare and overheating in vertical, south-facing windows with overhangs, simple sun control devices Limit glass facing east and west Section 5: Building Envelope Recommendations Slide 56

57 Section 6 LIGHTING DAYLIGHTING AND ELECTRICAL 57

58 Lighting Options Lighting energy use in schools One of largest end uses up to 40% On the top of the list for meeting 30% energy savings Inexpensive and offer rapid payback Helps to reduce cooling loads Lighting options for each climate zone Daylighting option provided and encouraged Significant energy savings potential Many non-energy benefits Non-daylighting yg goption provided for site or programming g constraints this option focuses on high performance lighting Both options available for 30% savings over ASHRAE Section 6: Lighting Slide 58

59 Daylighting General Concepts Daylighting in classrooms is most critical, then gyms South and north facing classrooms (more in DL-9) Vertical fenestration and toplighting provide interior illumination without excessive solar heat gain Use controls to take advantage of daylight Don t need high h performance lighting Reduced HVAC needs can offset daylighting costs Design to eliminate all direct beam glare from daylighting windows Solution should be simple and low maintenance Section 6: Lighting - Daylighting Slide 59

60 Daylighting General Strategies Toplighting Sidelighting Combined Section 6: Lighting - Daylighting Slide 60

61 Daylighting Techniques DL6: Separate Daylighting & View Glass Section 6: Lighting - Daylighting Slide 61

62 DL6: Separate View Windows from Daylighting Strategy View windows Provide a connection with outdoors Not a contributor to daylighting Light only the spaces very close to the window. Daylighting fenestration Include glazing g located above door height, about 7 ft. Build daylighting design around roof monitors high, south-side s light shelf apertures es high, north glass transom windows Section 6: Lighting - Daylighting Slide 62

63 Daylighting Techniques DL10: Ceiling Height Section 6: Lighting - Daylighting Slide 63

64 DL10: Ceiling Height Classrooms min. 10 ft ceiling If using only sidelighting, design a higher ceiling at the perimeter wall that s sloped Section 6: Lighting - Daylighting Slide 64

65 Daylighting Techniques DL12: No Direct Beam Section 6: Lighting - Daylighting Slide 65

66 DL12: Eliminate Direct Beam Radiation Eliminate uncontrolled, direct beam radiation onto the work plane Less critical for some gymnasiums, multipurpose spaces, and corridors Use strategies that bounce, redirect, and filter sunlight Can also use shading strategies Caution: Limit use of internal shading that relies on people results in reduced performance, increased first costs and long-term maintenance costs Section 6: Lighting - Daylighting Slide 66

67 Daylighting Techniques DL14: Light Interior Finishes Section 6: Lighting - Daylighting Slide 67

68 DL14: Interior Finishes for Daylighting Light colors increase light reflectance and reducing lighting and daylighting requirements Section 6: Lighting - Daylighting Slide 68

69 Daylighting Techniques DL20: Lightshelf h and Overhang Section 6: Lighting - Daylighting Slide 69

70 DL20: South-Facing Classrooms- Configuration of Apertures Light shelf recommended for south-facing walls Section 6: Lighting - Daylighting Slide 70

71 DL20: South-Facing Classrooms- Configuration of Apertures Overhang cut-off angle Section 6: Lighting - Daylighting Slide 71

72 Daylighting Final Techniques Roof Monitor & High VLT Glazing Section 6: Lighting - Daylighting Slide 72

73 Daylighting Final Techniques Skylights & TDD Section 6: Lighting - Daylighting Slide 73

74 DL5: Recommended Daylighting Fenestration to Floor Area Ratios Rules to determine the right amount of daylighting fenestration Section 6: Lighting - Daylighting Slide 74

75 DL8: Use Daylighting Analysis Tools to Optimize Design Guide helps achieve 30% savings without energy modeling Modeling benefits Evaluating energy saving trade-offs faster Daylighting designs more precise Section 6: Lighting - Daylighting Slide 75

76 DL9: Building Orientation Key to making daylighting cost effective Vertical daylighting facades oriented within 15 of north or south Orientation less important if toplighting Roof monitors can be rotated Main axis of the building should still be within 15 of north/south or east/west. East and west glass not good daylighting option Consider shading by buildings, trees, etc. when siting building Section 6: Lighting - Daylighting Slide 76

77 DL4: How to Select Daylighting Strategies AEDG recommends strategies for 3 classroom types and gym Section 6: Lighting - Daylighting Slide 77

78 DL20-27: Classroom Sidelighting All climate zones Sidelighting patterns appropriate for southand north-facing classrooms Section 6: Lighting - Daylighting Slide 78

79 DL28-DL35: Classroom Toplighting Daylighting for top floor or single story schools North or South facing clerestories Also good for gym Section 6: Lighting - Daylighting Slide 79

80 Classroom Sidelighting Plus Toplighting Combines sidelighting with small interior skylights kliht or roof monitors Section 6: Lighting - Daylighting Slide 80

81 Electrical Lighting General Concepts Use the most current, state-of-the art lamps, ballasts, controls, and techniques Use when daylighting options are not possible Lower lighting power density recommendations than daylighting option 1.11 W/ft2 in CZ ,2,5,6,7, W/ft2 in CZ 3 and 4 Low LPDs not as critical if lights are off Section 6: Lighting - Electrical Slide 81

82 EL1 & EL6: Interior Considerations EL1: Light-Colored Interior Finishes Ceiling reflectance greater than 70% EL6: Occupancy Sensors Manual on/auto off in all classrooms, offices, restrooms, and special use spaces Section 6: Lighting - Electrical Slide 82

83 EL2: Linear Fluorescent Lamps and Ballasts System efficacy is the mean lamp lumens per watt (MLPW) Efficacy recommendations for all climates: Daylighted option: linear fluorescent 75 min. Non-Daylighted option: linear fluorescent 85 min. Example of efficacy calculation: Section 6: Lighting - Electrical Slide 83

84 EL2: Linear Fluorescent Lamps and Ballasts Table shows lighting options that meet the efficacy recommendations Section 6: Lighting - Electrical Slide 84

85 EL3 to EL5: Lamp Types EL3: Fluorescent T5 Sources T5 lamps greater than 75 MLPW Enclosed luminaires and luminaires in tall spaces EL4: Compact Fluorescent 50 MLPW or greater, electronic ballast Use for utility lighting, down lighting, wall washing - not for general lighting EL5: Metal Halide 50 MLPW or 75 MLPW Use electronic ballast & pulse start t for less lumen depreciation Section 6: Lighting - Electrical Slide 85

86 EL10: Classroom Lighting Flat, white acoustical tile or gypsum board ceiling at least 9 ft 6 in. above the finished floor with a direct/indirect suspended lighting system Lighting system lends itself to three principal control scenes: Night, general lighting scene: All general lighting system lamps on Daytime, general lighting scene: General lighting system lamps affected by available daylight, either switching or dimming Any time, low-level scene: General lighting lamps off, controlled downlight lamps on or on with manual dimming controls Section 6: Lighting - Electrical Slide 86

87 EL10: Classroom Lighting Section 6: Lighting - Electrical Slide 87

88 EL10: Classroom Lighting Whiteboard lighting important, studies show increased retention Section 6: Lighting - Electrical Slide 88

89 EL11-EL16: Lighting for Special Spaces Gym, multipurpose room, library or media center, corridor, offices, lockers, restrooms Sections include tips and layout ideas Section 6: Lighting - Electrical Slide 89

90 Section 7 HEATING, VENTILATION, AND AIR- CONDITIONING 90

91 HVAC General Notes Use practical off-the-shelf technologies and strategies available from multiple manufacturers Especially important for HVAC Keep it simple Provide climate specific HVAC recommendations for typical system types Schools across country use many different solutions so guide accounted for this Recommendations look at whole system including things like duct design Section 7: HVAC Slide 91

92 What Type of HVAC System? chilled-water VAV unit ventilators small packaged rooftops 4b water-source heat pumps Section 7: HVAC

93 Heating and Cooling System Types Typical systems used that guide addresses 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 For each of the 6 systems above, book specifies Heating and cooling efficiency (SEER, EER, COP, AFUE, etc) Ventilation control and preconditioning Economizer use Fan efficiency Duct design Section 7: HVAC Slide 93

94 HVAC Recommendations Recommendations based on Climate zone System size (capacity) HVAC system type Fuel type (electricity or natural gas) Section 7: HVAC Slide 94

95 Integrated Design Concepts and HVAC First, reduce the load by doing the following Siting and orientation Glazing Envelope Lighting/daylighting g g g Plug loads Then, design an efficient HVAC system to meet any remaining loads See Chapter 2 on integrated design Section 7: HVAC Slide 95

96 HVAC Design Practices 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 Water heating Section 7: HVAC Thermal zoning Filters Duct design, construction Duct insulation Duct sealing, leak testing Testing, adjusting, balancing Commissioning Relief versus return fans Heating sources Noise control Proper maintenance Zone temperature control Operable windows Slide 96

97 HV8: Part-Load Dehumidification Basic constant-volume systems don t handle dehumidification well Minimize hours space relative humidity is above 60% Part-Load A/C can be a problem if dehumidifier is coupled to A/C Should be able to control A/C system so it can be cooling and/or dehumidifying Section 7: HVAC Slide 97

98 HV11: Ventilation Air Determined based on ASHRAE Single-Zone, Packaged Units, or Split DX Systems Each packaged DX unit have an OA connection that promotes mixing and minimizes temperature stratification i Also could use dedicated OA system to deliver OA directly to each zone WSHPs or GSHPs DOAS deliver conditioned OA directly to each zone, to the intake of each heat pump, or to the supply side of each WSHP Unit Ventilators Should have OA connection Or, DOAS could deliver OA directly to each zone or ventilator Section 7: HVAC Slide 98

99 HV11: Ventilation Air Fan-Coil Units DOAS deliver conditioned OA directly to each zone, to the intake of each fan-coil, or to the supply side of each fan-coil Multiple-Zone, Packaged VAV Rooftop Units Each unit have an OA intake that t promotes mixing i and minimizes temperature stratification Also could use dedicated OA system to deliver OA directly to each zone, to individual id VAV terminals, to OA intake of packaged VAV rooftop Multiple-Zone, VAV Air Handlers Each handler have OA intake to mix OA with recirculated air before going to zones Or, a DOAS used to deliver OA to each zone, to individual VAV terminals, or to OA intake of VAV handlers Section 7: HVAC Slide 99

100 HV11: Ventilation Air Tips on sizing system Use actual occupancy for calculations, not egress (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 Section 7: HVAC Slide 100

101 HV9 and HV14: Exhaust Air Energy Recovery and Demand-Controlled Ventilation Recommend either exhaust-air air energy recovery or demand-controlled ventilation (DCV) Apply differently based on system type Energy recovery: device total effectiveness of at least 50% for humid and dry climate zones (HV9) DCV: controls vary the OA based on zone need by a time-of-day schedule in the BAS an occupancy sensor a CO2 sensor (HV14) Section 7: HVAC Slide 101