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ENVIRONMENTAL DESIGN CONSULTANTS + LIGHTING DESIGNERS | atelierten.com Can Program Flexibility and Energy Efficiency Coexist? Jagan Pillai, PE, CEM, BEMP
ENVIRONMENTAL DESIGN CONSULTANTS + LIGHTING DESIGNERS | atelierten.com
Can Program Flexibility and Energy Efficiency Coexist?Jagan Pillai, PE, CEM, BEMP
Learning Objectives
• Learn about the challenges associated with designing an energy efficient lab where program
flexibility is key
• Understand the importance of tenant engagement in efficient design and operation of labs
• Approach towards analyzing and selecting appropriate mechanical systems for buildings with
program uncertainties
• Learn about how existing tenant occupied lab buildings perform
System Selection ParametersImpact of Functional, Operational, and Climatic Parameters
Functional Parameters
• Internal Loads
• Ventilation Requirements
• Exhaust Requirements
Operational Parameters
• Low Usage
• Typical Usage
• High Usage
Climatic Parameters
• Hot Climate
• Mild Climate
• Cold Climate
System Selection ParametersImpact of Functional, Operational, and Climatic Parameters
-100
0
100
200
300
400
500
LOW USAGE
TYPICAL USAGE
HIGH USAGE
LOW USAGE
TYPICAL USAGE
HIGH USAGE
LOW USAGE
TYPICAL USAGE
HIGH USAGE
LOW USAGE
TYPICAL USAGE
HIGH USAGE
LOW USAGE
TYPICAL USAGE
HIGH USAGE
LOW USAGE
TYPICAL USAGE
HIGH USAGE
SA
VIN
GS
IN
HV
AC
EN
ER
GY
US
E IN
TE
NS
ITY
(k
BTU
/ft
2/yr)
DECOUPLED VENTILATION DECOUPLED + WATERSIDE ECONOMIZER
AIR QUALITY SENSING DECOUPLED + AIR QUALITY SENSING
VARIABLE AIR VOLUME
HOT CLIMATE MILD CLIMATE COLD CLIMATE HOT CLIMATE MILD CLIMATE COLD CLIMATE
LOAD DRIVEN LAB VENTILATION DRIVEN LAB
3
1
5
2
4
1.Decoupling offers Max Savings for High
Usage Load Driven Labs in Hot Climates
2.Decoupling without Water Side Economizer
may be a Penalty for Mild & Cold Climates
3.Vent Rate Reduction offers no savings in
Load Driven High Usage All-Air Labs
4.Decoupling and Vent Rate Reduction offer
large savings for High Load & Usage Labs
5.Vent Rate Reduction offers substantial
savings for Ventilation Driven Labs
System Selection ParametersImpact of Functional, Operational, and Climatic Parameters
Functional Parameters
• Internal Loads
• Ventilation Requirements
• Exhaust Requirements
Operational Parameters
• Low Usage
• Typical Usage
• High Usage
Climatic Parameters
• Hot Climate
• Mild Climate
• Cold Climate
Both Function and Operational parameters become variables for core and shell lab buildings
-
2,000
4,000
6,000
8,000
10,000
12,000
14,000
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
STE
AM
US
AG
E (
mm
btu
)
STEAM CONSUMPTION COMPARISON ACTUAL
MODEL (UNCALIBRATED)
EAST AND WEST TOWER
0
500
1000
1500
2000
2500
3000
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
ELE
CTR
ICIT
Y U
SA
GE (
MW
h)
ELECTRICITY CONSUMPTION COMPARISON ACTUAL
MODEL (UNCALIBRATED)
EAST AND WEST TOWER
Findings From Measured Data - Example 1
Comparison at the beginning of the calibration process of an existing lab building in North East
Findings From Measured Data – Example 1
-
2,000
4,000
6,000
8,000
10,000
12,000
14,000
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
STE
AM
US
AG
E (
mm
btu
)
STEAM CONSUMPTION COMPARISON ACTUAL
MODEL (CALIBRATED*)
EAST AND WEST TOWER
0
500
1000
1500
2000
2500
3000
3500
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
ELE
CTR
ICIT
Y U
SA
GE (
MW
h)
ELECTRICITY CONSUMPTION COMPARISON ACTUAL
MODEL (CALIBRATED*)
EAST AND WEST TOWER
CV(RSME)# – 22%
#ASHRAE Guideline 14 limit for monthly usage calibration – 15%
CV(RSME)# – 36%
#ASHRAE Guideline 14 limit for monthly usage calibration – 15%
Profiles after removing supply air temperature reset
Lowering the plug loads helped improve the RSME values
-
2,000
4,000
6,000
8,000
10,000
12,000
14,000
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
STE
AM
US
AG
E (
mm
btu
)
STEAM CONSUMPTION COMPARISON ACTUAL
MODEL (CALIBRATED*)
EAST AND WEST TOWER
0
500
1000
1500
2000
2500
3000
3500
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
ELE
CTR
ICIT
Y U
SA
GE (
MW
h)
ELECTRICITY CONSUMPTION COMPARISON ACTUAL
MODEL (CALIBRATED*)
EAST AND WEST TOWER
CV(RSME)# – 13% CV(RSME)# – 17%
#ASHRAE Guideline 14 limit for monthly usage calibration – 15%#ASHRAE Guideline 14 limit for monthly usage calibration – 15%
Findings From Measured Data – Example 1
Findings From Measured Data – Example 2
Modeled vs Measured data for an office building
Facilities had to reset the SAT reset to constant SAT to
address humidity issues. This resulted in significant
heating energy increase.
SAT Vs Heat Recovery Effectiveness
0
0.2
0.4
0.6
0.8
1
50 55 60 65 70
SE
NS
IBLE
HE
AT
RE
CO
VE
RY
EF
EC
TIV
EN
ES
S
SUPPLY AIR TEMPERATURE (deg. F)
Actual Heat Recovery Effectiveness Vs. SAT
EFFECTIVENESS - 0.5
EFFECTIVENESS - 0.6
EFFECTIVENESS - 0.7
EFFECTIVENESS - 0.8Lower SAT without reset also limits the heat recovery
effectiveness
Efficient Dehumidification and SAT ResetStrategy 1: Dual wheel system
Strategy 2: Wrap-around coilEfficient Dehumidification and SAT Reset
Decoupling with Room Neutral Air Supply
▪ There is a large diversity in laboratory equipment usage
▪ Equipment are getting more efficient
▪ Laboratory use may change over time
Above factors can change the laboratory from being “Load Driven” during design to “Ventilation Driven” during operation
Decoupling with room neutral air supply can provide the required flexibility and eliminate the need for reheat
System Options:
▪ DOAS with Fan Coil Units
▪ 4-pipe VAV
Air Flow Reduction
Core and Shell Labs Energy Efficiency Measures
EUI
143kBtu/sf/yr
EUI
173kBtu/sf/yr
EUI
113kBtu/sf/yr
EUI
93kBtu/sf/yr
Building-level EEMs Plant-level EEMs
EUI
92kBtu/sf/yr
EUI
79kBtu/sf/yr
High Performance Case
• High performance envelope
• All LED lighting in common areas
• Low pressure drop fans system design and local FCU's with EC
motors
• Low flow plumbing fixtures
• Enhanced energy recovery system
• Dual wheel/wrap around coil at DOAS for efficient
dehumidification
• High performance central plant (condensing boilers, chillers with
WSE)
• Variable speed laboratory exhaust fan controls
Core and Shell Labs Energy Efficiency Measures
EUI
143kBtu/sf/yr
EUI
173kBtu/sf/yr
EUI
113kBtu/sf/yr
EUI
93kBtu/sf/yr
Building-level EEMs Plant-level EEMs
EUI
92kBtu/sf/yr
EUI
79kBtu/sf/yr
Exemplary Case ( Requires Tenant Participation)
• LPD reduction in tenant offices/labs
• Energy Star appliances
• Decoupled system configuration (CB/FCUs or 4-pipe VAV)
• Air-quality sensing to reduce background ventilation rate
• Low flow fume hoods and automatic fume hood control for labs
Plant Level Measures
0 8760
(HOURS)
COOLING
HEATING
Potentially provided from
heat recovery chillers
Maximizing heat recovery is key for achieving a low energy labs. Plant level measures such as heat recovery chillers and thermal energy
storage can help maximize energy savings.
Importance of Sensitivity Studies
System Selection ParametersSensitivity Study
VAV Vs. Chilled Beams
Sensitivity Study
$(4.00)
$(3.00)
$(2.00)
$(1.00)
$-
$1.00
$2.00
$-
$50,000
$100,000
$150,000
$200,000
$250,000
$300,000
1000 3000 5000 7000 9000 11000 13000 15000
NET
PR
ES
EN
T VA
LU
E (
MIL
LIO
NS
)
AN
NU
AL C
OS
T S
AV
ING
S
TES CAPACITY (Ton-hr)
TES OPTIMIZATION (SD PHASE PLUG LOADS) COST SAVINGS
NPV OF THE INVESTMENT
$(4.00)
$(3.00)
$(2.00)
$(1.00)
$-
$1.00
$2.00
$-
$50,000
$100,000
$150,000
$200,000
$250,000
$300,000
1000 3000 5000 7000 9000 11000 13000 15000
NE
T P
RE
SE
NT V
ALU
E (
MIL
LIO
NS
)
AN
NU
AL C
OS
T S
AV
ING
S
TES CAPACITY (Ton-hr)
TES OPTIMIZATION (25% LOWER PLUG LOADS) COST SAVINGS
NPV OF THE
INVESTMENT
$(4.00)
$(3.00)
$(2.00)
$(1.00)
$-
$1.00
$2.00
$-
$50,000
$100,000
$150,000
$200,000
$250,000
$300,000
1000 3000 5000 7000 9000 11000 13000 15000
NET
PR
ES
EN
T VA
LU
E
(MIL
LIO
NS
)
AN
NU
AL C
OS
T S
AV
ING
S
TES CAPACITY (Ton-hr)
TES OPTIMIZATION (HIGHER PLUG LOADS) COST SAVINGS
NPV OF THE INVESTMENT
• Net present value is optimum when the TES is sized between 6000-8000 ton-hr for Case 1 and Case 3
• For Case 2 a 5000 - 6000 ton-hr capacity TES yields an optimum net present value
CASE 1 CASE 2
CASE 3
System Selection Parameters
Thermal Energy Storage Sizing
Sensitivity Study
System Selection Parameters
Cogeneration Sizing
0%
20%
40%
60%
80%
100%
0 500 1000 1500 2000 2500 3000 3500 4000
AN
NU
AL L
OA
D F
AC
TOR
CAPACITY
UTILIZATION GRAPH (COGENERATION PLANT)
WASTE HEAT (LOW LOAD) WASTE HEAT (HIGH LOAD)
ELECTRICITY (LOW LOAD) ELECTRICITY (HIGH LOAD)
System Selection ParametersSensitivity Study
FLOOR-BY-FLOOR WATER
COOLED DX AHU WITH
CENTRAL CONDENSER
WATER LOOP
FLOOR-BY-FLOOR
CHW AHU WITH
CENTRAL WATER
COOLED CHILLED
WATER PLANT
ASHRAE
BASELINE
BEST CASEWORST
CASE
0% 16%-12%
ASHRAE
BASELINE
WORST
CASE
BEST CASE
23%0%-37%
- WATER-SIDE ECONOMIZER
- HIGH PERFORMANCE MODULAR CHILLERS
- PUMP STATIC PRESSURE RESET
- OVERSIZED CHILLERS WITHOUT VSD
- CONSTANT SPEED CHILLED WATER PUMP OPERATION
- NO CHILLED WATER TEMPERATURE RESET
- WATER-SIDE ECONOMIZER
- HIGH PERFORMANCE VARIABLE SPEED DX
- CW PUMP STATIC PRESSURE RESET
- NO CONDENSER WATER TEMP. RESET
- FAULTY ISOLATION VALUES
- LOWER EFFICIENCY DX UNIT
Floor-by-Floor Vs Central Chilled Water Plant
Setting EUI targetsDry Lab vs. Intensive Wet Lab
Site EUI
100 kBtu/sf 200 kBtu/sf 300 kBtu/sf
Exemplary
EUI260
kBtu/sf/yr
Base CaseExemplary
EUI173
kBtu/sf/yr
Base Case
150 250
EUI116
kBtu/sf/yr
High-Performance
EUI145
kBtu/sf/yr
EUI217
kBtu/sf/yr
High-Performance
EUI172
kBtu/sf/yr
EUI198
kBtu/sf/yr
EUI165
kBtu/sf/yr
EUI131
kBtu/sf/yr
ExemplaryBase CaseHigh-Performance
WET LAB
DRY + WET LAB
DRY LAB
Conclusion
Can program flexibility and energy efficiency co-exist? – Yes!
▪ It requires an integrated design process with involvement of all key stakeholders early in the design
▪ In core and shell buildings, Tenant involvement is key in achieving low energy laboratory buildings.Rethinking laboratory system ownership models and tenant leasing agreements are important.
▪ Reducing heating and reheat is one of the most important part of the building energy efficiency puzzle specially in cold climates. Tackling reheat efficiently is important to achieve goals like all-electric building/Carbon Neutrality/Net Zero Energy etc.
▪ Providing room neutral air supply with localized cooling and heating using FCUs/4-pipe VAV (in all or select areas) can significantly reduce both reheat and outside air heating energy
▪ Operational uncertainties should be taken into account during the design process to design and operate building requiring flexibility efficiently
▪ Sensitivity studies are critical for system sizing and selection for buildings where functional and operational parameters are variables/unknows.
▪ Shared lab spaces, space planning to improve effectiveness of passive and flexible modular labs, are key in designing energy efficient flexible labs
