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Tubman African American Museum
Christopher ChampagneMechanical Option2003 Senior Thesis
Christopher ChampagneMechanical Option
Tubman African American MuseumAtlanta, Georgia
Presentation Outline
Presentation GoalsExisting ConditionsExisting Mechanical SystemChiller OptimizationChilled Water PumpingLighting of Gallery SpaceConclusions and Recommendations
Christopher ChampagneMechanical Option
Tubman African American MuseumAtlanta, Georgia
Presentation Outline
Presentation GoalsExisting ConditionsExisting Mechanical SystemChiller OptimizationChilled Water PumpingLighting of Gallery SpaceConclusions and Recommendations
Christopher ChampagneMechanical Option
Tubman African American MuseumAtlanta, Georgia
Presentation Goals
Investigation of the air-cooled water chillers:• Museums have low load profiles during the evenings when
only the exhibit spaces or anywhere artwork is stored needs to be cooled.
• A smaller chiller for off-hours cooling and a larger one for occupied mode.
• Staging of the chillers to see if an energy savings could be realized.
Investigation of switching from constant speed pumping to variablespeed pumping:• Advantages of primary-only, variable speed pumping.• Possibility of switching the chilled water pumps in this case.• Should the switch be made?
Investigation of current lighting system in gallery space
Christopher ChampagneMechanical Option
Tubman African American MuseumAtlanta, Georgia
Presentation Outline
Presentation GoalsExisting ConditionsExisting Mechanical SystemChiller OptimizationChilled Water PumpingLighting of Gallery SpaceConclusions and Recommendations
Christopher ChampagneMechanical Option
Tubman African American MuseumAtlanta, Georgia
Existing Conditions
Location: Atlanta, GAUse: MuseumSize: 45,000 ft2
Two storiesConstruction Started:
October 2001Planned Completion:
Spring 2004Construction Cost:
$15.5 million
Christopher ChampagneMechanical Option
Tubman African American MuseumAtlanta, Georgia
Design Team
The PRD Group, Ltd Exhibit Designer
Souza, True and Partners, Inc. Structural
Vanderweil Engineers M/E/P
Harmon-Piedmont Construction, LLC
CM/GC
E. Verner Johnson and Associates, Inc.
Architect
Christopher ChampagneMechanical Option
Tubman African American MuseumAtlanta, Georgia
Presentation Outline
Presentation GoalsExisting ConditionsExisting Mechanical SystemChiller OptimizationChilled Water PumpingLighting of Gallery SpaceConclusions and Recommendations
Christopher ChampagneMechanical Option
Tubman African American MuseumAtlanta, Georgia
Existing Mechanical System
(2) 121.5 ton HCFC-22 air-cooled water chillers
(3) 290 GPM chilled water pumps
(2) 25,000 CFM constant volume and (1) 18,000 CFM variable volume custom air handling unit.
Christopher ChampagneMechanical Option
Tubman African American MuseumAtlanta, Georgia
Chilled Water Equipment
(2) Trane Air-Cooled Water Chillers121.5 tons290 GPMEWT = 55 ˚FLWT = 45 ˚FHCFC-22 RefrigerantScrew compressor
(3) Bell & Gossett 1510 - 2 ½ BB Pumps290 GPM65 ft. head1750 RPM10.0 motor HP(1) Pump Standby
Christopher ChampagneMechanical Option
Tubman African American MuseumAtlanta, Georgia
Presentation Outline
Presentation GoalsExisting ConditionsExisting Mechanical SystemChiller OptimizationChilled Water PumpingLighting of Gallery SpaceConclusions and Recommendations
Christopher ChampagneMechanical Option
Tubman African American MuseumAtlanta, Georgia
Chiller Optimization Technique
The maximum cooling load is 189.1 tons on July 15th at 2 pmusing Atlanta Bin Data and Carrier’s Hourly Analysis Program(HAP).
Engineering Equation Solver (EES) was used to simulate two equalsize air-cooled chillers
1. Trane Air-Cooled Series R Rotary Liquid Chillers Model RTAA 125 (Design Capacity = 120.1 ton)
2. Trane RTAA 110 (Design Capacity = 108.5 ton)3. Trane RTAA 100 (Design Capacity = 100.6 ton).
Upper capacity that one chiller would run before the second chillerwas run was varied from 85% to 100% of capacity to see which isthe most efficient. The lower capacity at which the second chillerwould turn off was set to 40%.
Christopher ChampagneMechanical Option
Tubman African American MuseumAtlanta, Georgia
Chiller Optimization Equations
The optimization equations used in the EES simulation are from the California Energy Commission’s 2001 Non-Residential Alternative Calculation Methods (ACMs) document, specifically Chapter 2 entitled “Reference Method and Required Modeling Capabilities for Alternative Calculation Methods (ACMs).”
The following three terms are functions of chilled water supply temperature (Tchws) and the outdoor dry-bulb temperature (Toa). They are used to establish the efficiency of the chiller operation.
CAP_FT is the full load capacity as a fraction of rated capacity. It is a capacity correction that is a function of those terms.
EIR_FT is the full load efficiency (kW/ton) as fraction of ratedcapacity. It is an efficiency correction factor.
EIR_FPLR is the fraction of full load power as a function of fraction of full load output.
Christopher ChampagneMechanical Option
Tubman African American MuseumAtlanta, Georgia
EES Model Cases
10040113.6100.6100L
10040108.5108.5110K
10040120.1120.1125J
9540113.6100.6100I
9540108.5108.5110H
9540120.1120.1125G
8540113.6100.6100F
8540108.5108.5110E
8540120.1120.1125D
9040113.6100.6100C
9040108.5108.5110B
9040120.1120.1125A
Cap. (%)Cap. (%)
UpperLowerkWTonModelCase
Christopher ChampagneMechanical Option
Tubman African American MuseumAtlanta, Georgia
Electrical Utility Rates
6.910¢ per kWhNext 190,000 kWh
8.026¢ per kWhNext 7,000 kWh
8.757¢ per kWhFirst 3,000 kWh
All consumption (kWh) not greater than 200 hours200 hours times the billing demand.
$14.00Base Charge (includes first 25 kWh or less
The electricity would be provided by Georgia Power (a subsidiary of Southern Company).
PLM-3 rate which is for small to medium building size.
“Not less than 30 kW but less than 500 kW.”
Christopher ChampagneMechanical Option
Tubman African American MuseumAtlanta, Georgia
Annual Operating Cost and Time
7214,12181,393929,304L
3313,58381,763934,654K
1112,67081,284927,718J
10714,90788,9641,038,866I
5513,96685,299985,828H
2413,13684,717977,400G
121115,35093,4951,104,441F
91214,76293,7941,108,762E
61014,03492,9811,096,997D
11815,01488,9641,038,866C
8914,33989,2911,043,601B
4613,61888,5721,033,188A
RankingsRankings(hrs)($)(kWh)
Operating TimeCost
Operating Time
Operating CostAECCase
Christopher ChampagneMechanical Option
Tubman African American MuseumAtlanta, Georgia
Annual Operating Cost
75,000
80,000
85,000
90,000
95,000
Cost
($)
1
Annual Energy Cost
A B C D E F G H I J K L
Christopher ChampagneMechanical Option
Tubman African American MuseumAtlanta, Georgia
Life Cycle Cost of Chillers
$75,000100.6100C
$84,000108.5110B
$96,000120.1125A
First Cost (FC)TonModelCase
Where:FC = first cost of plantUCj = plant utility cost for year jMCj = relative maintenance cost for year jd = discount rateN = number of years of analysis
MCj = $500d = 12 %N = 20
The following formula from CoolTools was used in the calculation of the LCC.
( ) ( )( )∑=
+÷++=N
j
jjj dMCUCFCLCC
1
1
Christopher ChampagneMechanical Option
Tubman African American MuseumAtlanta, Georgia
Life Cycle Cost of Chillers
$706,880.98
$698,458.84
$686,695.15
500,
000.
00
550,
000.
00
600,
000.
00
650,
000.
00
700,
000.
00
750,
000.
00
Cost ($)
RTAA 125
RTAA 110
RTAA 100Tr
ane
Mod
el
Num
ber
LCC of Different Size Chillers
Christopher ChampagneMechanical Option
Tubman African American MuseumAtlanta, Georgia
Chiller Optimization Recommendation
• The RTAA 100 has the smallest life cycle costbased on the assumptions stated above.• However given its tonnage being only slightlyabove the design cooling load, this might not be awise selection.• The RTAA 110 would still provide cost savingsover the RTAA 125 (LCC savings = $10,422.14), alongwith some added safety to the designer.• The staging should be set to 100% of capacityof the first chiller before the second chiller is turned on.
Christopher ChampagneMechanical Option
Tubman African American MuseumAtlanta, Georgia
Presentation Outline
Presentation GoalsExisting ConditionsExisting Mechanical SystemChiller OptimizationChilled Water PumpingLighting of Gallery SpaceConclusions and Recommendations
Christopher ChampagneMechanical Option
Tubman African American MuseumAtlanta, Georgia
Chilled Water Pumping
One method of saving energy used by a building is changing the primary pumps of a primary-only, chilled water system from constant speed to variable speed.
Important Considerations:
Does the chilled water system meets the requirements for being switched from constant speed to variable speed pumps?
What is the overall economic benefit along with benefits that are not quantifiable?
Christopher ChampagneMechanical Option
Tubman African American MuseumAtlanta, Georgia
Advantages of Variable Speed Pumps
• Improved efficiency (motor and pump) and consequently energy savings.
• Reduced system noise.• Improved control of system flow to respond to flow
and pressure requirements of the system.• Extended motor life due to soft stops & starts
which puts less wear and tear on the parts of the pump.
• Lower installation cost.• The control valve in the bypass ensures that
neither of the chillers would become “starved” during a low load situation, as flow is diverted directly from the supply back to the chillers.
Christopher ChampagneMechanical Option
Tubman African American MuseumAtlanta, Georgia
Possibility of Switching Pumps
Trane mentions four situations where variable primary flow should notbe used (Trane, 1999). They are for system where:
System chilled-water temperature is critical. Examples are a “cleanroom” or computer chip making plants.• Although there are specific temperature and humidity guidelines
for a museum, they are not critical. Slight temporary fluctuations will not cause permanent damage to the artifacts.
The system flow rate, and consequently the load, does not vary.• The load does vary in the Tubman Museum, between the occupied
hours and the unoccupied hours. Also, due to the large transient load of occupants, the location of the load varies frequently within the inside of the building during the occupied hours.
It is unlikely that the owner/operator will run the plant as designed.• This is a slight area of concern, but something that doesn’t
eliminate the use of variable speed pumps for the system.Existing chiller controls are old and inaccurate.• This is a new construction project, so this also is not a concern.
Christopher ChampagneMechanical Option
Tubman African American MuseumAtlanta, Georgia
Current Piping Schematic
CHILLER 1 (CH-1):CAPACITY = 121.5 TONSHCFC-22 REFRIGERANT (2) SCREW COMPRESSORS (10) CONDENSER FANS 1.0 HP EACH 850 RPMAMBIENT MAX = 95°FAMBIENT MIN = 23°F
CHILLER 2 (CH-2):CAPACITY = 121.5 TONSHCFC-22 REFRIGERANT (2) SCREW COMPRESSORS (10) CONDENSER FANS 1.0 HP EACH 850 RPMAMBIENT MAX = 95°FAMBIENT MIN = 23°F
AFTER CHILLER:LWT = 45°F290 GPM
AFTER CHILLER:LWT = 45°F290 GPM
BEFORE CHILLER:EWT = 55°F290 GPM
BEFORE CHILLER:EWT = 55°F290 GPM
CHWS
CHWR
CHWS
CHWR
AIRSEPARATOR
EXPANSIONTANK
CS PUMP (P-4):
FOR ALL PUMPS:290 GPMWATER TEMP. = 55°FNPSHR = 8.4 FTHEAD = 65 FTPUMP RPM = 1750BHP = 7.25MOTOR HP = 10
CS PUMP (P-3):
CSPUMP (P-6):(STAND BY)
SHOT CHEMICALFEEDER
PRESSURERELIEF VALVE
BALL VALVEBUTTERFLY VALVEBUTTERFLY VALVE WITH MEMORY STOP (BALANCING VALVE)CHECK VALVESTRAINER W/BALL VALVE, HOSE BIBB & CAP
AUTOMATIC CONTROL VALVE, MODULATING ACTUATOR
COMBINATION FLOWMETER/SHUT OFF/BALANCING VALVE (CIRCUIT SETTER)
UNION OR FLANGE
LEGEND:
AHU-1A&1B(LOAD)
AHU-2(LOAD)
Christopher ChampagneMechanical Option
Tubman African American MuseumAtlanta, Georgia
Proposed Piping Schematic
CHILLER 2 (CH-2):CAPACITY = 108.5 TONSHCFC-22 REFRIGERANT (2) SCREW COMPRESSORS (10) CONDENSER FANS 1.0 HP EACH 850 RPMAMBIENT MAX = 95°FAMBIENT MIN = 23°F
BALL VALVEBUTTERFLY VALVEBUTTERFLY VALVE WITH MEMORY STOP (BALANCING VALVE)CHECK VALVESTRAINER W/BALL VALVE, HOSE BIBB & CAP
AUTOMATIC CONTROL VALVE, MODULATING ACTUATOR
COMBINATION FLOWMETER/SHUT OFF/BALANCING VALVE (CIRCUIT SETTER)
UNION OR FLANGE
AFTER CHILLER:LWT = 45°F290 GPM
FOR ALL PUMPS:290 GPMWATER TEMP. = 55°FNPSHR = 8.4 FTHEAD = 65 FT
VS PUMP (P-3):
VS PUMP (P-4):
VSPUMP (P-6):(STAND BY)
EXPANSIONTANK
LEGEND:
CHWR
AIRSEPARATOR
CHWS
SHOT CHEMICALFEEDER PRESSURE
RELIEF VALVE
CHWS
CHWR
CHILLER 2 (CH-2):CAPACITY = 108.5 TONSHCFC-22 REFRIGERANT (2) SCREW COMPRESSORS (10) CONDENSER FANS 1.0 HP EACH 850 RPMAMBIENT MAX = 95°FAMBIENT MIN = 23°F
BEFORE CHILLER:EWT = 55°F290 GPM
AFTER CHILLER:LWT = 45°F290 GPM
AHU-1A&1B(LOAD)
BEFORE CHILLER:EWT = 55°F290 GPM
AHU-2(LOAD)
Christopher ChampagneMechanical Option
Tubman African American MuseumAtlanta, Georgia
Chilled Water Bypass Control
Normally closed control valve.
Permits the operation of a single chiller below its low flow limit.
Programmed to maintain only the minimum flow for each chiller that is on as opposed to constant flow, which would waste energy.
Located near to the chillers so that the pressure drop throughout the system can drop as the coil loads drop.
Christopher ChampagneMechanical Option
Tubman African American MuseumAtlanta, Georgia
Additional Costs
Savings:The three-way valves are replaced with two-way valves at the AHU’s.Less piping needs to be around the load with the elimination of the three-way valves.Steel schedule 40 piping, which costs $97 per linear foot for 6” piping for 100 feet of piping, meaning a savings of $9,700.Costs:A control valve in the bypass has to be added in the bypass line, which would typically cost $1950.Three variable frequency drives must be purchased each costing $5,800.Additional cost = $9,650.
Christopher ChampagneMechanical Option
Tubman African American MuseumAtlanta, Georgia
Cost Savings – Energy
There are several different techniques available forcalculating the energy savings (kWh) for variablespeed pumps.
Carrier’s Hourly Analysis Program (HAP)Bell & Gossett ESP-Plus Online ProgramEngineering Equation Solver (EES)
The results from EES will be presented further.
Christopher ChampagneMechanical Option
Tubman African American MuseumAtlanta, Georgia
Engineering Equations Solver (EES)
The following terms were created using lookup tables:Flow Rate vs. HeadFlow Rate vs. Pump EfficiencyPercent of Nameplate Load vs. Motor EfficiencyPercent of Design Speed vs. Drive Efficiency (for theVariable speed pumps only)Individual functions were created for:Total PowerPump EfficiencyPump Model CurvePercent of Nameplate LoadDeciding Number of Pumps Operating Based on the LoadSpeed the Variable Speed Pumps Operate At
Christopher ChampagneMechanical Option
Tubman African American MuseumAtlanta, Georgia
Engineering Equations Solver (EES)
Christopher ChampagneMechanical Option
Tubman African American MuseumAtlanta, Georgia
Engineering Equations Solver (EES)
Christopher ChampagneMechanical Option
Tubman African American MuseumAtlanta, Georgia
Life Cycle Cost of Pumps
Where:FC = first cost of equipmentUCj = utility cost for year jMCj = relative maintenance cost for year jd = discount rateN = number of years of analysis
The following formula from CoolTools was used in the calculation of the LCC.
( ) ( )( )∑=
+÷++=N
j
jjj dMCUCFCLCC
1
1
In this example:FCconstant = $0FCvariable = $9,650MCj = $500d = 12%N = 20 yearsUCj constant speed = $4,092UCj variable speed = $2,369
Christopher ChampagneMechanical Option
Tubman African American MuseumAtlanta, Georgia
Payback Period of Pumps
Initial Additional Cost for Variable Speed Pumps = $9,650
Yearly Savings= $1,723.53
Payback Period= $9,650 / $1,723.53= 5.6 years
Christopher ChampagneMechanical Option
Tubman African American MuseumAtlanta, Georgia
Chilled Water Pumping Conclusion
Based solely on cost, it makes sense to switch from constant speed pumps to variable-speed pumps.
The LLC is $3,219.85 less for variable speed.
The payback period is slightly lengthy, but realistic.
Christopher ChampagneMechanical Option
Tubman African American MuseumAtlanta, Georgia
Presentation Outline
Presentation GoalsExisting ConditionsExisting Mechanical SystemChiller OptimizationChilled Water PumpingLighting of Gallery SpaceConclusions and Recommendations
Christopher ChampagneMechanical Option
Tubman African American MuseumAtlanta, Georgia
Lighting of Gallery Space
The lighting system for a gallery space in the museum (Collection Gallery 255) was designed using industry guidelines.
The IESNA Lighting Handbook – Ninth Edition (2000)
Christopher ChampagneMechanical Option
Tubman African American MuseumAtlanta, Georgia
Placement of Luminaries
X = (Ceiling height – eye level) * 0.577= (15’-0” – 5’6”) * 0.577= 66” = 5’-6”
Christopher ChampagneMechanical Option
Tubman African American MuseumAtlanta, Georgia
Lightscape Renderings
Southeast corner of room from above
South of the room from above
Christopher ChampagneMechanical Option
Tubman African American MuseumAtlanta, Georgia
Target Illuminance
The IESNA Lighting Handbook target illuminancefor:
Flat displays and 3-dimensional objects is 300 lx (30 fc)
Lobbies, general gallery areas and corridors is 100 lx (10 fc).
Christopher ChampagneMechanical Option
Tubman African American MuseumAtlanta, Georgia
Photometric Data
Southeast corner of room from above
Christopher ChampagneMechanical Option
Tubman African American MuseumAtlanta, Georgia
Photometric Data
South of the room from above
Christopher ChampagneMechanical Option
Tubman African American MuseumAtlanta, Georgia
Lighting of Gallery Space Conclusion
The new lighting design is compliant with the lighting requirements stated in the IESNA Lighting Handbook for illuminance.
Artwork and artifacts are accentuated.
Christopher ChampagneMechanical Option
Tubman African American MuseumAtlanta, Georgia
Presentation Outline
Presentation GoalsExisting ConditionsExisting Mechanical SystemChiller OptimizationChilled Water PumpingLighting of Gallery SpaceConclusions and Recommendations
Christopher ChampagneMechanical Option
Tubman African American MuseumAtlanta, Georgia
Conclusions and RecommendationsThe RTAA 110 would still provide cost savings (LCC savings = $10,422.14) over the RTAA 125, along with some added safety to the designer and should be selected.
The staging should be set to 100% of capacity of the first chiller before the second chiller is turned on.
The primary-only, chilled water pumps should be switched from constant speed pumps to variable-speed pumps. The LCC is $3,219.85 less for variable speed. Variable speed control also has some advantages that are not quantifiable in economic terms.
The new lighting design is compliant with the lighting requirements stated in the IESNA Lighting Handbook.
Christopher ChampagneMechanical Option
Tubman African American MuseumAtlanta, Georgia
Acknowledgements
I would like to thank the following people who have made my thesis possible:• The Pennsylvania State University Department ofArchitectural Engineering faculty including:
• My advisor, Dr. James Freihaut• Dr. William Bahnfleth and Dr. Stanley Mumma• Jonathan Dougherty, Moses Ling, M. Kevin Parfitt and Kenneth Davidson
• Vanderweil Engineers, especially Heather Tsatsarones and Ron Edwards
• Fellow architectural engineering students who have lent their knowledge and expertise
• Mom, Dad and Jen who are always there for me• My friends who have been understanding and helpful
Christopher ChampagneMechanical Option
Tubman African American MuseumAtlanta, Georgia
Questions
Thank you for your time
Any questions ???