Unit-IV; Professional Sales Representative (PSR).pptx
Ian Doebber Handout
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
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3. Presentation Overview
• K-12 Advanced Energy Design Guide
• Rebuilding New Orleans Schools : Quick Start Schools
• High Performance Schools in Humid Climates
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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
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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
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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
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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
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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
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9. Quick Start Schools: Daylighting Design
From AEDG Classroom Daylighting Recommendations
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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29. Desiccant Wheels
Hot Gas
DX
65 gr/lb
/lb
53 gr/lb
57ºF 75ºF
65ºF
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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
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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
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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
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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
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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
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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”
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