1. IEA Annex 40
CITE-AHU:
An Automated Commissioning Tool for CAV
Air-Handling Units
Natascha Castro, NIST
Hossein Vaezi-Nejad, CSTB

2. CITE-AHU Commissioning of the Installation and Technical Equipment
-Air Handling Units
Outline
n Commissioning Process
n Development of CITE-AHU
¨ Test automation
¨ Expert rules
¨ Interface
n Commissioning the ARIA Building
¨ Design Review
¨ Manual Cx Results
¨ Automated Cx Results
n Savings Estimate/ Payback
n Conclusions
2

3. AHU Commissioning Process (from CTPL)
Step 1: Design Review-
check control logic, sensor placement and sensor accuracy.
M not currently emphasized in protocols
A Step 2: Operator Interview-
N for existing buildings, ask building operator whether the air handling
U units are operating properly to the best of their knowledge.
iterative!
A
L Step 3: Installation Review and Verification-
conduct a field inspection to determine installed characteristics of the
B equipment including condition and sensor availability
update documents
E
M Step 4: Forced Response Testing and Analysis-
S complete passive testing with BEMS, before active testing
manipulate the system under test by means of setpoint changes and
sensor overrides. Document along with mode changes.
Evaluate data for compliance.
3

4. Automation of functional test scripts
1. Verify communications link
2. Run pre-coded test sequence from library
Value Displays as
READ is completed
This is the line number to input
to change reference value
4

5. Procedure for Cx Analysis
CAV 1. Import test data
VAV
2. Specify data relationships
3. Specify system functionality
4. Analyze using modified APAR rules
5. Compare to archived tests for On-going Cx
CITE-AHU
5

6. Expert rules- AHU Performance Assessment Rules (House)
• Enhanced for constant air volume systems
• Considers additional equipment (heat recovery)
CITE-AHU
CITE -AHU
Provides greater
transparency of rule logic
(tool tips )
6

7. Commissioning the ARIA Building
Step 1 Design Review: AHU3
¨ Design Review
¨ Manual Cx
¨ Automated Cx
n Serves Offices &
Converted space
n 100% outdoor air
n Modes:
¨ Heating
¨ Free cooling
w/ Heat recovery &
Manual Bypass
7

8. Step 2 Operator Interview: Mr. Laurent Auriau
n Candid w/ good knowledge of (undocumented) system history.
UNIT PROBLEM DESCRIPTION
AHU3 Zones partitioned for office spaces w/o
changing ventilation configuration
General Cannot change the controllers schedule,
setpoints revert to a nightly shutoff at
midnight and 05:00 startup
...
8

9. Step 3 Installation Review and Verification
Outdoor Air Temp. Sensor
9

10. Step 4 Forced Response Testing and Analysis
(passive w/ BEMS) UNIT PROBLEM DESCRIPTION &
EFFECT
ALL System schedule in
override.
(Controls installer left test
s t Auto-Cx testing
First Auto-Cx test of AHU3
TRA AHU3
program active)
30 2
1 2d
n Auto-Cx testing TSA AHU3
period without fault
period with fault TOA
25
1 am 4 am 1m
a 4 am
UHC AHU3
Supply Fan
20
1
15
Temp (°C)
Cmd 0-1
10
0
5
0
06/10/2003 07/10/2003 07/10/2003 07/10/2003 07/10/2003 07/10/2003 08/10/2003 08/10/2003 08/10/2003
19:12 00:00 04:48 09:36 14:24 19:12 00:00 04:48 09:36
-5 1-
10

11. Step 3 Forced Response Testing and Analysis (active w/ BEMS)
First Auto Cx tests were conducted on AHU3 over two nights
1st night- Fault free with 2nd night- Faulty condition BEMS
pumps in manual override logic error causes pumps to cycle off
First Auto-Cx test of AHU3
30 2 TRA AHU3
1s t Auto-Cx testing 2nd Auto-Cx testing TSA AHU3
period without fault period with fault
TOA
25
1 am 4 am 1 am 4 am UHC AHU3
Supply Fan
20
1
Temp (°C)
Cmd 0-1
15
10
0
Finding:
5 Cooling coil is undersized for 17°C (62.6°F).
**Laboratory needs are not met- fan coil units added.
0
06/10/2003 07/10/2003 07/10/2003 07/10/2003 07/10/2003 07/10/2003 08/10/2003 08/10/2003 08/10/2003
19:12 00:00 04:48 09:36 14:24 19:12 00:00 04:48 09:36
-5 -1
11

12. Step 3 Forced Response Testing and Analysis (active w/ BEMS)
AHU2 Cooling coil capacity step test:
Return Temp. setpoint is changed from 20°C -> 19°C (3 hours) -> 18°C (3 hours) ->
17°C (3 hours)
.
Tra,s AHU2
Auto-Cx test of AHU2
Tra AHU2
Auto-Cx testing Auto-Cx testing period
Tsa AHU2
25 period without fault. w ith fault.Tra,s not 1.5
Ucc AHU2
23
1
21
Temp (°C)
Cmd 0-1
19 0.5
17
0
Finding: Cooling coil is undersized for 17°C (62.6°F).
15
**Laboratory needs are not met- fan coil units added.
13 -0.5
1/22/2004 1/22/2004 1/22/2004 1/22/2004 1/23/2004 1/23/2004 1/23/2004
14:24 16:48 19:12 21:36 0:00 2:24 4:48
12

13. To-Date Results
Unit Fault Solution
Automate damper control based on
AHU3 Operating with heat recovery in summer
outdoor and return air temperatures
AHU1,
Outdoor air temperature Provide sensor shading
2 and 3
Return air temperature sensor is located Correct the location of the return air
AHU1,2 downstream of the outdoor air supply duct temperature sensor
Supply air temperature setpoint (21°C), Reduce supply air temperature setpoint
AHU 3 results in nighttime heating in summer in summer
Boilers Boilers in manual override in summer Apply summer schedule
Chiller Condenser is 50% fouled Clean condenser fins
Exhaust duct from AHU1 is connected to the Redesign exhaust system for AHU 1
AHU1,3 exhaust of AHU 3 and update design drawings
AHU3 Nighttime shutdown not in effect Shutdown system 12 am - 5 am
AHU1, Forced continual operation of AHUs due to a
Remove test program
2 and 3 test program installed in 2000
**Green= Manual Cx Blue= Bems Assisted Cx **Orange= comfort Yellow= energy 13

14. To-Date Results, cont’d
Unit Fault Solution
AHU2, AHU2 is set for 24 hour operation which does not match the Synchronize equipment
Chiller operation of the chilled water pumps, stopped 12am-7am operation
The cooling coil of AHU1 was added after the construction
of the building and is connected directly to the chiller Add a dedicated pump
AHU1 (without a separate pump) It is not possible to suspend for cooling coil
delivery of cooling water to this AHU
Boilers operate even when commanded off (pumps shut Force at least one boiler
Boilers down, boilers still operate) to stop
Ensure that the
AHU3 circulation pump cycles with the boiler. The heating
circulation pump
AHU3 coils are not supplied with hot water when the boilers cycle
off. operates independent of
the boiler.
Reduce the open period
The open period of the boiler isolation valves (3 mn) is too
Boilers of the boiler isolation
long for the on/off period of the boilers (2mn)
valves to 1mn
AHU2 Return air temperature sensor reading does not match Replace faulty temp
overlay sensor, system sensor is faulty. sensor
14

15. Gas Savings Estimate
Correct the boiler control logic
n Boiler plant ran 24/7 to avoid occupant discomfort.
n The control logic error was corrected January 5, 2004.
¨ improved comfort for occupants
¨ decreased gas consumption
¨ increased protection of the boiler plant equipment.
Weekly Gas Consumption vs Mean Outdoor Temp (C)
Winter Season Estimate:
700€ ?10% Gas Energy Savings
15

16. Electrical Energy Savings Estimate
Correct scheduling errors Annual estimate:
for AHUs and pumps 4141€ ? 47% Electrical Energy Savings
Energy Energy Energy Cost
Power
Equipment use before use after savings savings
(kW)
Cx (kWh) Cx (kWh) (kWh) €
Fan AHU 2 2.2 19219 8580 10639 798
Fan AHU 3 8 69888 33280 36608 2746
Pump AHU & FCU (HW) 0.4 3494 1664 1830 137
Pumps Zone 1,2,3 0.067 585 279 307 23 x 3
Pump Zone 4 (HW) 0.047 410 196 215 16
Pump Zone 5 0.169 1476 703 773 58
Pump AHU & FCU (CW) 0.825 7207 3432 3775 283
Pump Zone 4 (CW) 0.1 873 416 457 34
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17. Conclusions
n Some adaptation required for new systems
n CITE_AHU detected 3 faults in 4 automated tests
n Scheduling errors (€)
n Cooling Coil & Heating coil Undercapacity
n Boilers sequencing
n Development of automated tools must be used in conjunction with
good protocol for system design reviews
¨ Limitations to automated testing (i.e., detecting sensor
placement errors)
n Quantitative energy benefits
¨ Excludes service requests Total gain 5000 €
¨ Equipment life
Project cost 15000 €
¨ Heat recovery
Pay back 3 years
n Non-quantitative benefits also achieved- comfort, operator
knowledge, maintenance, documentation
17

18. Future development
n Define specific test scenarios (with user-changeable parameters)
n Integrate test scenarios into CITE_AHU interface
n Automate documentation of test results
¨ Incorporate required manual test and documentation archive
n Test VAV systems, Expand for other configurations
n Investigate Manufacturer interest to provide integrated package.
Questions?
18