The Center for theCreative and Performing Arts
High School
Pittsburgh, PA
CAPAHigh School
Pittsburgh, PA
Andrew Tech Mechanical Option Spring 2003
CAPAHigh School
Pittsburgh, PA
Andrew Tech Mechanical Option Spring 2003
Presentation Outline
□ Introduction / Background
□ Existing Conditions
□ Mechanical Analysis
□ Lighting Analysis
□ Conclusions &
Final Recommendations
CAPA High School Pittsburgh, PA
Introduction / Background
CAPA High School Pittsburgh, PA
Architect MacLachlan, Cornelius & Filoni Architects, Inc.
General Contractor Mascaro Construction Company
Mechanical Engineer
Firsching, Marstiller, Rusbarsky & Wolf Engineering, Inc.
Lighting / Electrical Carl J. Long & Associates
Structural Engineer Brace Engineering
Owner Pittsburgh Public Schools
Project TeamIntroduction &
Background
Introduction / Background
■ Located in Pittsburgh’s Cultural District
■ Magnet School■ 550 – 600 students■ Highly specialized
education in
□ Music□ Theater□ Dance□ Visual Arts □ Literary Arts
CAPA High School Pittsburgh, PA
Pittsburgh’s Golden Triangle
Introduction / Background
□ 400 – Seat Theater
□ 6 Story Stage-House
□ Orchestra Pit
□ Stage Craft Shop
□ Old-fashioned Marquee
Architectural Features
□6-story Glass Curtain Wall
□Orchestra / Choral Rehearsal Hall
□Dance Studio
□Black Box Theater
□Green Space
CAPA High School Pittsburgh, PA
Architecture
□ 175,000 sf – Total□ 133,000 sf – New□ 42,000 sf – Renovation□ $36 million□ June 2001 - August 2003
Mechanical Analysis
CAPA High School Pittsburgh, PA
Intent of Analysis
Determine Applicability of Cool Tools Optimization Procedure
Cool Tools: Chilled Water Plant Design Guide▫ Chapters 6 & 7
□ Survey of Design Professionals Develop a typical chilled water plant design procedure Determine when Engineers optimize their designs
□ Application of Optimization Procedure□ Comparison of Procedures
Costs Energy Consumption
Mechanical
Analysis
Mechanical Analysis
Typical Design Process
□ Chilled Water distribution system Based upon size of system and past experiences
□ Chilled Water temperatures, flow rates, & pipe sizes Typically 2.4 gpm/ton Use of standard 10ºF ΔT
Q = 500*gpm*ΔT → gpm = Q/(500*ΔT) Pipe Sized using equal friction method
CAPA High School Pittsburgh, PA
Mechanical Analysis
Typical Design Process
□ Cooling Tower Manufacturer’s Selection Software Speed control
▫ Past Experience
Range – standard 10ºF ΔT (default value) Flow rate – 3 gpm/ton Approach – standard 7ºF (default value)
□ Chiller Selection Determine Load using computer program (HAP, TRACE, etc.) Select number of chillers based on required redundancy Chiller size = Load / number of chillers Manufacturer’s catalogs & vendor recommendations
CAPA High School Pittsburgh, PA
Mechanical Analysis
Cool Tools’ Optimized Design Procedure
□ Chilled Water distribution system Recommendations based on general rules-of-thumb
□ Chilled Water temperatures, flow rates, & pipe sizes 3-step procedure to determine system ΔT based on
“maxing-out” the flow in pipes▫ First cost optimum▫ Reasonable flexibility▫ Reduces energy costs
CAPA High School Pittsburgh, PA
Mechanical Analysis
Cool Tools’ Optimized Design Procedure
□ Cooling Tower 3-step procedure to select condenser water temperature range Increase efficiency (gpm/hp) Vary Approach Develop performance Specification and collect bids from
manufacturers
□ Chiller Selection Determine design load using computer program Develop performance Specification and collect bids from
manufacturers Estimate building energy consumption with detailed computer
model Calculate Life-Cycle Cost (LCC) estimate and select chiller
arrangement with lowest LCC
CAPA High School Pittsburgh, PA
Mechanical Analysis
CAPA High School Pittsburgh, PA
Cool Tools Optimization Design Procedure
Step - 1 – Select chilled water distribution system flow arrangement.
Step - 2 – Select chilled water temperatures, flow rate, and primary pipe sizes.
Step - 3 – Select tower speed control option, efficiency, condenser water temperature range and approach temperatures. Make preliminary cooling tower selection.
Step - 4 – Select chillers using performance specification & life-cycle analysis.
Step - 5 – Adjust tower sizing and number of cells if necessary.
Step - 6 – Finalize piping system design and select pumps.
Step - 7 – Develop and optimize control sequence.
Application of Optimization Procedure
Mechanical Analysis
CAPA High School Pittsburgh, PA
Application of Optimization Procedure
Building Load Profile
0
500
1000
1500
2000
2500
10 20 30 40 50 60 70 80 90 100
Percent Load
Ho
urs
per
Yea
r
Design Load▫ Carrier’s Hourly Analysis Program (HAP)
▫ Peak Design Load = 500 tons
▫ Hourly Analysis of Building Load for entire year
Mechanical Analysis
From Table 6-1
Application - 6▫ Many small coils
Primary-Secondary Variable Flow
CAPA High School Pittsburgh, PA
Step - 1 – Select chilled water distribution system flow arrangement.
Primary-secondary variable flow arrangement
Application of Optimization Procedure
Mechanical Analysis
Step 2.1 – Determine flow rate using a low end of 12 ºF ΔT & a high end of 18 ºF ΔT
CAPA High School Pittsburgh, PA
Step - 2 – Select chilled water temperatures, flow rate, and primary pipe sizes.
Application of Optimization Procedure
Step 2.2 – Pick smallest pipe from Table 6-8 & adjust ΔT to “max-out” pipe size
Step 2.3 – Choose ΔT based on results
Chilled Water Supply Temperature = 44 ºF Chilled Water ΔT = 14 ºF Primary Pipe Size – 8” Main Riser Pipe Size – 6”
Mechanical Analysis
Tower Speed Control▫ Two-speed tower (full/half)
Condenser Water Temperature Range▫ Similar selection method as chilled water ΔT ▫ Actual Result ΔT = 10.8 ºF ▫ Used ΔT = 12 ºF
Approach▫ Limited to 7 ºF
Efficiency▫ Limit size of cooling tower to that of original tower
CAPA High School Pittsburgh, PA
Step - 3 – Select tower speed control option, efficiency, condenser water temperature range and approach temperatures. Make preliminary cooling tower selection.
Cooling Tower Selections▫ Marley’s Update Selection Software
Application of Optimization Procedure
No Cap EWT LWT EAT°F HP
WB EACH
NC8302E2 2 500 1000 97 85 78 2 10 480-3-60 1.00NC8303DL2 2 500 1000 97 85 78 2 7.5 480-3-60 1.06
°F NO. Voltage
Cooling Tower Selections
Model No. GPM MOTORS Cost Ratio Index
Cells tons °F
Mechanical Analysis
CAPA High School Pittsburgh, PA
Step - 4 – Select chillers using performance specification & life-cycle analysis.
Chiller Selection
4 Arrangements Heat Exchanger Enabled
▫ 2 – 250 ton Centrifugal Chillers
▫ Constant and Variable Speed
No Heat Exchanger▫ 1 – 150 ton Centrifugal Speed
▫ 1 – 350 ton Centrifugal Speed
▫ Variable & Constant arrangements
Application of Optimization Procedure
Mechanical Analysis
CAPA High School Pittsburgh, PA
Step - 4 – Select chillers using performance specification & life-cycle analysis.
Chiller Selection
Detailed Life-Cycle Cost (LCC) Analysis▫ 8 scenarios
WSFC - Heat Exchanger On/Off 4 Chiller Combinations 2 Cooling Tower Arrangements Pumping based on 14 ºF ΔT
▫ Energy Consumption Modeled in Engineering Equation Solver (EES)
▫ Annual Utility & LCC calculated in Microsoft Excel
Application of Optimization Procedure
Mechanical Analysis
CAPA High School Pittsburgh, PA
Step - 4 – Select chillers using performance specification & life-cycle analysis.
Chiller Selection LCC Analysis
▫ 8% discount rate over 15 years
Application of Optimization Procedure
E 234,987$ -- 38,202$ -- 401,265 -- 234,987$ --S - 1 223,679$ 1 34,074$ 8 342,702 6 223,679$ 2S - 2 225,393$ 2 33,164$ 6 331,866 5 225,393$ 1S - 3 254,263$ 5 32,884$ 3 328,424 4 254,263$ 6S - 4 255,977$ 6 31,771$ 1 316,361 1 255,977$ 3S - 5 308,644$ 7 33,077$ 4 330,994 3 308,644$ 8S - 6 310,358$ 8 32,011$ 2 320,504 2 310,358$ 7S - 7 245,321$ 3 33,896$ 7 359,249 8 245,321$ 5S - 8 247,035$ 4 33,082$ 5 351,176 7 247,035$ 4
N = years of analysis
LCC Rank
8.00 15
Life-Cycle Cost (LCC) Analysis
Scenario Number
First Cost Rank Utility Cost RankAnnual
Energy Use (kWh)
RankDiscount Rate (%)
Chiller Selection Scenario 2
▫ HX Enabled; 2 – 250 ton Constant Speed Chillers; NC8303DL2
Mechanical Analysis
Cost Savings
0
10,000
20,000
30,000
40,000
50,000
60,000
70,000
80,000
First Cost ($) Annual Utility Cost($)
LCC ($) Annual Energy Use(kWh)
CAPA High School Pittsburgh, PA
Step - 4 – Select chillers using performance specification & life-cycle analysis.
Chiller Selection
Application of Optimization Procedure
Costs and Energy Savings
0
100000
200000
300000
400000
500000
600000
First Cost ($) Utility Cost ($) LCC ($) Annual Energy(kWh)
Existing
Scenario 2
9,594$ 4.0%
69,399 17.3%
5,038$ 13.0%
52,720$ 9.4%Total LCC Savings
Cost Savings of Scenario 2
First Cost Savings
Annual Energy Savings (kWh)
Annual Utility Costs Savings
Mechanical Analysis
CAPA High School Pittsburgh, PA
Step - 5 – Adjust tower sizing and number of cells if necessary.
Step - 6 – Finalize piping system design and select pumps.
Step - 7 – Develop and optimize control sequence.
Application of Optimization Procedure
Mechanical Analysis
CAPA High School Pittsburgh, PA
Comparison of two procedures
Typical Procedure
□Advantages Common in Industry Less time consuming Results in working system
□Disadvantages Not optimum design Higher initial cost Higher operational cost
Optimization Procedure
□Advantages Results in OPTIMUM system Lower initial costs Lower operational costs
□Disadvantages Time consuming
▫ Engineer▫ Equipment vendors
Not common in Industry
Mechanical Analysis
CAPA High School Pittsburgh, PA
Conclusions
Is the Optimization Procedure Applicable to typical chilled water plant designs?
No
Survey Says:
Too time consuming Cost Prohibitive Extra Fee for Client
Mechanical Analysis
CAPA High School Pittsburgh, PA
Conclusions
□Use 3-step procedure to determine flow rates & ΔTs
Advantages▫ Reduces First Cost
Pumps Cooling Tower Pipes, Valves, Insulation, etc.
▫ Reduces Operating Costs
Disadvantages▫ Increased Coil Sizes Offset by savings
Lighting Analysis
Intent of Analysis
□ Decrease Power Density of Lighting□ Provide adequate illumination levels
Space DescriptionRoom 133 & 212
2-story Art Gallery
874 square feet
2nd Floor Balcony
Showcase for Student Artwork
CAPA High School Pittsburgh, PA
Lighting
Analysis
Lighting Analysis
Existing Design
□ 31 - Track Mounted Fixtures 75 W Parabolic Incandescent Lamps
□ 12 - Recessed Downlight Fixtures 2 - 26 W Quad Compact Fluorescent Lamps
CAPA High School Pittsburgh, PA
Lighting Analysis
■ ASHRAE Standard 90.1-1999 – Energy Standard for Buildings
□ General Exhibition within a Museum□ 1.6 W/ft2
CAPA High School Pittsburgh, PA
Number of Fixtures
Fixture # of Lamps -
WattageBallast Factor
Input W (w/ ballast)
Total Wattage
31 Track 1 - 75W -- 75 2325
12 Downlight 2 - 26W 1.1 57.2 686
Power Density - Existing Design
3011
874
3.45
Total Wattage (W) :
Area (ft2) :
Power Density (W/ft2) :
Lighting Analysis
New Design
□ 13 - Wallwash Fixtures 1 - 55 W Long Tube Compact Fluorescent Lamp
□ 12 - Recessed Downlight Fixtures 2 - 26 W Quad Compact Fluorescent Lamps
CAPA High School Pittsburgh, PA
Lighting Analysis
■ Compliant with ASHRAE Standard 90.1-1999
CAPA High School Pittsburgh, PA
Number of Fixtures
Fixture # of Lamps -
WattageBallast Factor
Input W (w/ ballast)
Total Wattage
13 Wallwash 1 - 55 W 0.98 53.9 701
12 Downlight 2 - 26W 1.1 57.2 686
Power Density - New Design
1323
874
1.51
Total Wattage (W) :
Area (ft2) :
Power Density (W/ft2) :
< 1.6 W/ft2
Lighting Analysis
■Illuminance Levels
□ IESNA Handbook Museum - flat display on a vertical surface Category D
▫ Visual tasks of high contrast and large size▫ 30 fc (300 lux)
CAPA High School Pittsburgh, PA
Lighting Analysis
CAPA High School Pittsburgh, PA
■ Lightscape Images
Lighting Analysis
■Advantages
□ Compliance with ASHRAE Std. 90.1-1999
□ Elimination of “hot spots”
□ Even distribution of illuminance
□ Lower maintenance costs
□ Color Temperature matches downlights
□ Longer Life
■Disadvantages
□ Reduction in Color Rendering capabilities
□ No directivity
CAPA High School Pittsburgh, PA
Summary
Conclusions / Recommendations
■Mechanical Analysis
□ Optimization Procedure Not Feasible for all plant designs
▫ Cost Prohibitive▫ Time constraints
□ Selection of flow rates & ΔT 3-step procedure
▫ First Cost Savings (CAPA – 4%)▫ Operational Cost Savings (CAPA – 13%)▫ Takes only minutes to perform
CAPA High School Pittsburgh, PA
Conclusions &
Recommendations
Conclusions / Recommendations
■Lighting Analysis
□ Use wallwash fixtures Reduces power density
▫ Compliance with ASHRAE Std. 90.1-1999
Even distribution of illuminance levels Adequate illuminance on display surfaces
CAPA High School Pittsburgh, PA
AcknowledgementsJim Kemper - Firsching, Marstiller, Rusbarsky & Wolf Engineering, Inc.
Ken Lee - MacLachlan, Cornelius & Filoni Architects
Jamie White & Chuck Urso - LLI Technologies, Inc.
Kent Lewis - Carl J. Long & Associates
Dr. William P. Bahnfleth Prof. Moses Ling Jonathan Dougherty
Other members of the AE Faculty
Family & Friends
Questions?
Mechanical Analysis
Step 1- Determine flow rate using 12 ºF ΔT & 18 ºF ΔT
CAPA High School Pittsburgh, PA
Step - 2 – Select chilled water temperatures, flow rate, and primary pipe sizes.
Application of Optimization Procedure
Section Load (tons) Application GPMPipe Size
(in)GPM
Pipe Size (in)
Primary Piping 500 Non-Noise Sensitive, constant speed 1000 8 667 8Main Riser 380 Noise Sensitive, variable speed 760 6 507 6AHU-4 70 Non-Noise Sensitive, variable speed 140 3 93 2-1/2AHU-5 60 Non-Noise Sensitive, variable speed 120 3 80 2-1/2
Chilled Water Flow Rate Requirements using ∆T = 12 °F and ∆T = 18 °F
∆T = 12 °F ∆T = 18 °F
Mechanical Analysis
Step 2 – Pick smallest pipe from Table 6-8 & adjust ΔT to max-out pipe size
CAPA High School Pittsburgh, PA
Step - 2 – Select chilled water temperatures, flow rate, and primary pipe sizes.
Application of Optimization Procedure
Section Load (tons) ApplicationPipe Size
(in)Max GPM
Resulting ∆T
Primary Piping 500 Non-Noise Sensitive, constant speed 8 1115 10.8Main Riser 380 Noise Sensitive, variable speed 6 765 11.9AHU-4 70 Non-Noise Sensitive, variable speed 2-1/2 107 15.7AHU-5 60 Non-Noise Sensitive, variable speed 2-1/2 107 13.5
Chilled Water Flow Rates for Main Distribution Pipes
Section Load (tons) ApplicationPipe Size
(in)GPM ∆T
Primary Piping 500 Non-Noise Sensitive, constant speed 8 857 14.0Main Riser 380 Noise Sensitive, variable speed 6 670 13.6AHU-4 70 Non-Noise Sensitive, variable speed 2-1/2 105 16.0AHU-5 60 Non-Noise Sensitive, variable speed 2-1/2 107 13.5
Chilled Water Design flows and ∆Ts
Mechanical Analysis
Step 3 – Choose ΔT based on results
CAPA High School Pittsburgh, PA
Step - 2 – Select chilled water temperatures, flow rate, and primary pipe sizes.
Chilled Water ΔT = 14 ºF
Application of Optimization Procedure
Mechanical Analysis
CAPA High School Pittsburgh, PA
■Energy Model
□ Components modeled in EES
Chillers▫ DOE2 & Modified DOE2 model
Coupled polynomials Coefficients from California Energy Commission
Cooling Towers▫ Curve-fit polynomial regressions of performance curves
Marley Update Selection Software
Pumps▫ Polynomial equations using pump characteristics
Heat Exchanger▫ Heat transfer equations
Mechanical Analysis
CAPA High School Pittsburgh, PA
■Criteria for pipe-sizing of Table 6-8
□ Velocity is limited to minimize erosion Based on common rules-of thumb
□ Velocity limited by noise Based on general rules-of-thumb
□ Life-cycle cost of piping and associated pumping system
Analysis performed in San Francisco Bay Area (1992)
Existing Conditions
Mechanical□ 2 – 260 ton Water-cooled Centrifugal Chillers□ 1 – 2 cell cooling tower - 1560 gpm□ 2 – 3,853 MBtu Natural Gas Boilers□ Plate & Frame Heat Exchanger for Water-Side Free
Cooling (WSFC)□ Heat Recovery Unit□ 10 Air Handling Units□ VAV, CAV, & Direct Ventilation□ Carbon Dioxide Monitors□ 40+ Sound Attenuators□ Integrated DDC & Pneumatic Control System
CAPA High School Pittsburgh, PA