Technology and Engineering Development (TED) Building
Thomas Jefferson National Accelerator Facility
Newport News, VA
Presentation Overview
Project Background
• Site, use, and architecture
Existing Mechanical System
• Air system, hydronic system, geothermal system
Horizontal Directional Drilling (Depth 1)
• An alternative geothermal solution
Radiant Floor Slab Cooling (Depth 2)
• An exploration of slab thermal capacity
David Blum | Mechanical Option
Dustin Eplee | Adviser
Architectural Engineering | The Pennsylvania State University
Construction Schedules and Costs for Alternatives (Breadth 1)
• Presented after each depth
Final Conclusions
General Building Information
Site
Size:
70,000 SF
Stories Above Grade:
Two
Architecture Design and Use
1st Floor
• Research Workspaces
• Highbay Area
Project Team
Owner:
CMGC:
A/E:
Cost Consultant:
Thomas Jefferson National Accelerator Facility
Newport News, VA
Jefferson Lab
Mortenson Construction
EwingCole
Crawford Consulting Services, Inc
2nd Floor
Dates of Construction:
8/4/2010 – 9/30/2011
• Offices, Conference, and
Administration
Cost:
$16 million
• Health Club, Break Room
Project Delivery Method:
Design-Bid-Build
• Main Mechanical Room
Hydronic System
Air System
Variable Air Volume with Terminal Reheat
•
AHU 1:
32,000 CFM serves 1st Floor and Highbay
•
AHU 2:
32,000 CFM, 2nd Floor
•
Fan Powered Boxes serve perimeter zones
•
VAV Boxes serve interior zones
Outdoor Air Pre-Conditioning
•
OAU 1:
7,500 CFM serves AHU 1
•
OAU 2:
6,800 CFM serves AHU 2
•
Total Energy Wheel exchanges latent and sensible
heat with exhaust
Hybrid Condenser System
12 Central Water to Water Heat Pumps
•
Chilled Water:
•
•
Cond. Water:
Hot Water:
•
Cond. Water:
42 F Supply, 50 F Return
85 F Entering, 95 F Leaving
• 3 Fields
120 F Supply, 110 F Return
• 192 Wells
55 F Entering, 45 F Leaving
• 300 ft Depth
14
• Full Heating Load
•
EER:
•
10 Chilled Water, 6 Hot Water
Boiler
• Backup heat source
Vertical Bore
Geothermal
• 72 % Cooling Load
Closed Circuit
Cooler
• 28% Cooling Load
Depth 1: Full Load Geothermal Design
Goals
•
Add field to meet full cooling load: 67 additional tons
•
Minimally invade tree line (per owner)
Existing and Proposed Geothermal Fields Field Type
Horizontal Trench
Existing
• 2500 ft2/ton and $600 to $800 / ft2
Proposed
• 167,500 ft2 required is too large
Vertical Bore
• 250 ft2/ton and $900 to $1100 / ft2
•
Compare energy use and first costs to current hybrid
condenser system
• 16,750 ft2 required eliminates trees
Horizontal Directional Drilling
• Horizontal bores under obstacles
• Up to 600 ft long and 45 ft deep
176,000 ft2
• Stacked vertically in ground
Geothermal Design
Bores
•
Total Length:
•
Layout
Energy and Operation
Annual Energy Use
21441 ft
• Closed Circuit Cooler (1599 hrs):
89,429 kWh
Length per Bore: 450 ft
• Total Current HVAC:
646,138 kWh
•
No. Bores:
48
• Total Proposed HVAC:
556,709 kWh
•
No. Rows:
16, 3 stacks (15 ft, 30 ft, 45 ft)
• Savings:
13.8%
•
Spacing:
15 ft
•
Diameter:
5”
•
Pipe:
1” HDPE
•
Grout:
Bentonite (k = 1.0 hr-ft-F/Btu)
Pumps
• 1100 GPM
• VFD
Life Cycle
• Operational Savings:
-$5,982/ yr
• Additional First Costs:
$178,096
• Simple Payback:
30 years
Installation Process
HDD Geothermal Construction
Budget and Schedule Impact
Cost
• Current Condenser:
$756,074
• Closed Circuit Cooler:
$51,054
• Vertical Bore Field:
$687,936
• Pumps:
$17,084
• Proposed Condenser:
• HDD Field:
$934,170
$229,150
• Difference: +$178,096 (+7.3% HVAC Budget)
Schedule Impact
•
Field Installation and Equipment Mobilization:
62 Days (~12.5 Weeks)
Depth 2: Radiant Floor Cooling Slabs
Goals
Radiant Slab Implementation
1st Floor
Radiant Slab Design Conditions
Floor Surface Temperature: 68 F
Indoor Air:
•
Explore the capabilities of floor slab thermal storage
•
Analyze cooling capacity and effects on air system
•
Compare daily cooling energy use and power demand
profile with current HVAC system
78 F, 50% RH, 58 F DP
1st Floor 5” NW Slab on Grade
• Covering:
•
2nd
Floor
3/ “
8
Conductive Concrete (ESD)
PEX Tubing Depth: 4” Below Surface
• CHWS Temp:
61 F
2nd Floor 3 ¼” LW Elevated Slab on Metal Deck
• Covering:
•
3/ “
8
¼” Carpet
PEX Tubing Depth: 1 ½” Below Surface
• CHWS Temp:
55 F
Required Cooling Airflow
Load and Energy Model
Excel Spreadsheet Model
Proposed Systems
Radiant Slab System
20000
•
Adapted RSTM method
18000
•
Distribution Pump:
187 GPM, 7.5 HP
•
Hourly slab temperature from heat balance
16000
•
3 Heat Pumps, EER:
16
14000
•
Slabs in series
70
75.00
60
74.00
72.00
40
71.00
30
70.00
20
Radiant Floor Slab
Required Vent Air
8000
73.00
50
Current Design
10000
Slab Temperature (F)
Chilled Water Flow (GPM)
AHU 1:
16,825 CFM
4000
•
AHU 2:
15,446 CFM
2000
•
CHW Distribution Pump:
350 GPM, 15 HP
0
•
6 Heat Pumps, EER:
14
6000
Slab Temperature (F)
68.00
0
67.00
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
Time (hr)
2_ 2_O
Co ffi
n ce
2_ f ere
He n
a ce
2_ lth C
M
ec lub
h
2_ /Ele
Co c
rri
do
CU r
H
CR -2
U
21
69.00
10
Parallel Air Systems
•
1_
W
or
ks
h
1_
1 o
Co _O p
m ffic
pu e
1_ ter
M
ec Lab
h
1_ /Ele
Co c
1_ rrid
Hi or
gh
Ba
CU y
H
CR -1
U
CR 1-1
U
12
Chilled Water Flow (GPM)
12000
Daily Energy Use by Component
Currently Designed System
Daily Energy Use
Breadth: Radiant Floor Construction
Cost
Radiant Slabs System
• Current HVAC System:
• AHUs:
$372,290
• Pumps:
$12,336
• Radiant Slab HVAC System:
Current Design
Radiant Slabs
Savings
Peak Demand:
283 kW
205 kW
27.5%
Total Usage:
3,725 kWh
3,238 kWh
13.1%
$2,450,000
$2,613,000 (+6%)
• AHUs:
$185,920
• Pumps:
$18,126
• Radiant Floor:
$319,625
Schedule Impact
• 26 weeks with one crew
• 2 weeks with Climate Mat
Final Conclusions
Geothermal Systems
•
Hybrid geothermal systems can reduce first costs
while still reducing energy use
•
Horizontal Directional Drilling offers ability to install
geothermal fields with little land disturbance
Radiant Floor Slabs
•
Can be used to flatten demand profile
•
Controllability becomes important because cooling
effect is not instant
Acknowledgements
A special thank you to the following people and
parties that made this project possible:
Jefferson Lab, TED Owner
EwingCole, Architects, Engineers, and Interior Designers
Eric Joesten, Director of Mechanical Engineering, EwingCole
Kate Mondock, Mechanical Engineer, EwingCole
Dustin Eplee, Thesis Adivsor
Mentors on the Thesis Class Discussion Board