7/27/2019 Economizer Procedure.rtf http://slidepdf.com/reader/full/economizer-procedurertf 1/36 CxTPL Upgrade Project Oct. 31, 2001 GENERAL COMMISSIONING PROCEDURE FOR ECONOMIZERS Prepared for: Pacific Gas & Electric Company, Customer Energy Management Non-Residential New Construction Program Development of a Commissioning Test Protocol Library Project Alyssa Newman, Project Manager Ken Gillespie, Project Lead Prepared by: Pacific Gas & Electric Company, Technical and Ecological Services, Performance Test and Analysis Unit Richard Fromberg The project “Development of a Commissioning Test Protocol Library” is funded by California utility customers and administered by Pacific Gas & Electric Company under the auspices of the California Utilities Commission. Legal Notice Pacific Gas and Electric Company (PG&E) makes no warranty or representation, expressed or implied, with respect to the accuracy, completeness, or usefulness of the information contained in this report, or that the use of any information, apparatus, method, or process disclosed in this report may not infringe upon privately owned rights. Nor does PG&E assume any liability with respect to use of, or damages resulting from the use of, any information, apparatus, method, or process disclosed in this procedure.
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Pacific Gas & Electric Company,Customer Energy Management Non-Residential New Construction Program
Development of a Commissioning Test Protocol Library Project
Alyssa Newman, Project Manager Ken Gillespie, Project Lead
Prepared by:
Pacific Gas & Electric Company,
Technical and Ecological Services, Performance Test and Analysis UnitRichard Fromberg
The project “Development of a Commissioning Test Protocol Library” is funded by California
utility customers and administered by Pacific Gas & Electric Company under the auspices of theCalifornia Utilities Commission.
Legal Notice
Pacific Gas and Electric Company (PG&E) makes no warranty or representation, expressed or implied, with respect to the accuracy, completeness, or usefulness of the information contained in
this report, or that the use of any information, apparatus, method, or process disclosed in thisreport may not infringe upon privately owned rights. Nor does PG&E assume any liability with
respect to use of, or damages resulting from the use of, any information, apparatus, method, or process disclosed in this procedure.
General Commissioning Procedure for Economizers October 31, 2001
FOREWORD
This procedure provides example protocols for two fictitious buildings (one located in
Sacramento and the other in San Francisco) for steps that need to be taken to fully commission
their air handling system’s economizers. Variations are provided when requirements between thetwo examples differ. Each building has integrated, built-up economizers, with return, exhaust
and outside air dampers, but different sequences of operation and designs.
In commissioning an economizer, the intent is to optimize the use of outside air for cooling a
building, in order to minimize energy use, while maintaining good indoor air quality. Our
primary goal is to verify that the economizer is working as specified, while looking for opportunities to improve upon its intended operation. This procedure was developed with the
assistance of PG&E’s Commissioning Test Protocol Library’s Templates. Following is an
outline of what protocols are included here:
Project/Building DescriptionDescription of Systems Under Test
Equipment Covered by this ProtocolSequences of Operation
Acceptance and Responsibilities
Verification ChecksChecks for Documentation and Training
General Commissioning Procedure for Economizers October 31, 2001
I. PROJECT / BUILDING DESCRIPTION
BUILDING NAME and ADDRESS: APPLICATION #: 1
Case 1) Sac’s Service Center (SSC)
4444 Perk Road, Sacramento CA 95826 and
Case 2) Pete’s Excellent Cuisine (PEC)
185 Energy Street, San Francisco, CA 94102
BUILDING CONTACT PERSONS and PHONE NUMBERS: 1) Zachery Sac, 916-123-4567 2) Peter Cook, 415-123-4567
NAME & FIRM OF PERSON(S) DOING TESTS: JR Doolittle, Hotwire Commissioning Services
PLANNED DATE(S) OF TEST: December 21-23, 2001
Description of Systems Under Test:1) The SSC has three air handler units (AHU’s) #1, #2 and #3, which serve the north, south, and southeast sections of the
main building. Supply and return fans are VFD controlled. A DDC system controls separate actuators on the outside
air, return air and exhaust air dampers. AHU#1 and AHU#2 are roof mounted; AHU#3 is floor mounted at the east
end of the building.
The air handlers are designed to provide hot and cold duct air flows that will maintain 0.25 “wg supply air duct static
pressures and a supply air temperature set point of 55°F. Minimum supply air rate is limited to 25% of the total
capacity. The sequence of operation for each AHU is the same, except for scheduling differences. The environment is
a hot/dry central valley climate with seasonal temperatures ranging from 15°F -105°F and the cooling load is ~75 tons
@ 40,000 cfm per AHU.
2) The PEC has one air handler unit, AHU-1, which serves a multi-zone, single duct, reheat system that conditions the
whole building. AHU-1 is a central station, pull-thru type, roof mounted air handling unit complete with economizer
(return, outside, exhaust) damper section, filter section, chilled water cooling coil section and fan section with variable frequency drive (VFD) control of the supply fan motor. Exhaust fans are propeller type fans within the air handler exhaust section.
The air handler is designed to provide conditioned air at the temperature and pressure required by the variable volume
(VAV) terminal units and outside air as required for (IAQ) ventilation. It also provides exhaust air as required to
maintain a slight building positive pressure during economizer operation. The environment is a coastal climate withtypically mild temperatures ranging from 35°F to 95°F and the cooling load is ~60 tons max @ 32,000 cfm.
The air handler is designed to provide air flow that will maintain between 1” and 2”wg supply air duct static pressure
and supply air temperature set point between 65 and 55°F.
General Commissioning Procedure for Economizers October 31, 2001
Equipment Covered by this Protocol: Economizers of AHU’s 1, 2, and 3 at the SSC and AHU-1 at the PEC.
General Notes:
1. This commissioning procedure addresses verification checks and functional testing of moderately sized packaged or
built-up air handlers.
2. In all test sections, circle or highlight any results that indicate deficiencies (i.e. responses that don’t meet the criteria for acceptance). Acceptance requires correction and retest of all deficiencies, as defined in each test section under
“Criteria for Acceptance” or “Acceptance”. Attach all retest data sheets.
3. This Commissioning Procedure does not comprehensively address fire and life safety or basic equipment safety
controls.
4. To ensure that this Commissioning Procedure will not damage any equipment or affect any equipment warranties, have
the equipment manufacturers’ representative(s) review all test procedures prior to execution, and be present if possible.
General Commissioning Procedure for Economizers October 31, 2001
II. SEQUENCES OF OPERATION
Case #1 - The economizer air dampers (outside, return and exhaust) shall be modulated by an analog output from the DDC
system to maintain the desired cold deck temperature set point. A minimum of 45F mixed air temperature will be maintained at
all times.
Cooling supply air temperature shall be maintained by first modulating the outdoor air damper open via the economizer mode
and then secondly modulating the chilled water valve open. When the outdoor air temperature is within 2F (adjustable) below
the warmest zone space temperature, the outside air damper shall go to the minimum position setting and the return damper
shall open to maximum position. The heating supply air temperature shall be reset downwards to the return air temperature as
required to maintain a zone temperature of 70F(adjustable) in the coldest room.
A photoelectric duct smoke detector shall be installed in the supply duct and shall provide a digital input to the DDC system.
When smoke is detected by the smoke detector, the air handler supply fan shall be de-energized via its variable frequency drive,
the return fan shall be de-energized via its VFD, and the outside air damper shall be fully closed.
All damper actuators shall be programmed to achieve full range adjustability (closed to 100% open) in 60 seconds (adjustable).
Case #2 – AHU-1 is programmed to operate (on/off) on a predetermined building occupancy schedule (adjustable).
When the supply fan is de-energized, the outside damper shall close and the cooling coil chilled water control valve TCV-1 shall
open to the full bypass position.
The supply fan is energized one hour (adjustable) prior to scheduled occupancy to provide a warm-up cycle. The outside air
damper shall remain closed and the cooling coil chilled water control valve shall remain open to the full bypass position during the warm-up. The warm-up cycle shall be terminated when return air temperature TS-4 reaches 70°F.
The supply air temperature TS-3 shall be controlled by modulating the economizer dampers and then the cooling coil chilled water control valve TCV-1 in sequence to maintain the supply air temperature at set point. Outside air via the economizer
dampers shall be the primary source of cooling when outside air temperature TS-1 is below 72°F and less than the return air temperatureTS-4, otherwise cooling shall be provided by chilled water via TCV-1. No chilled water shall be supplied to
TCV-1 when outside air temperature TS-1 is below 61°F. Supply Air Temperature TS-3 setpoint shall be reset by greatest
cooling demand from 55F to 65F. When outside air temperature TS-1 is greater than 72°F or greater than the return air
temperature TS-4 the economizer dampers shall be positioned to provide the minimum design outside air CFM.
Building static pressure DPX-1 shall be maintain at 0.03”wg for economizer operating mode only. No set point control is
required for minimum outside air operating mode. Supply Air Duct Static Pressure DPX-2 setpoint shall be reset via AHU-1 supply fan VFD by greatest cooling demand from 1.0” wg to 2.0” wg.
ALARM SETPOINTS:
Building Static Pressure DPX-1: 0.07 “ wg.Supply Air Duct Static Pressure, High: 2.4 “wg, Low: 0.06 “wg
Supply Air Temperature TS-3, Low: 50°F
Return Air Temperature TS-4, High: 76°F, Low: 60°F
Mixed Air Temperature TS-2, Low: 50°F Filter (Dirty) Differential Pressure DPS-2: 1.0 wg.
General Commissioning Procedure for Economizers October 31, 2001
III. ACCEPTANCE AND RESPONSIBILITIES:
We the undersigned participated in this commissioning effort, and acknowledge that the processes for which we were
responsible have been checked and all required corrections have been made.
1. Name: Joe Contractor
Company name: Installation Contractor Associates
Responsibilities:
Verification Checks: Installation quality, dampers must match position commanded by DDC
Functional Testing: Dampers must respond to DDC commands in time, reliably, and accurately.
Signature:
2. Name: John Programmer
Company name: DDC Inc.
Responsibilities:
Verification Checks: DDC must be capable of commanding dampers to the required positions based on operating
mode. Pre-operational forced response testing must be verified.
Functional Testing: DDC must be capable of commanding dampers to the required positions based on operatingmode, OAT conditions, and as specified in the sequence of operation
Signature:
3. Name: JR Doolittle
Company name: Hotwire Commissioning Services
Responsibilities:
Verification Checks: Complete the commissioning plan, ensure that all corrections are made, retest if necessary,
use best engineering judgement to achieve design intent.
Functional Testing: Complete the commissioning plan, ensure that all corrections are made, retest if necessary, use
best engineering judgement to achieve design intent.
Signature:
4. Name: Zachary Sac
Company name: Sac’s Service Center
Responsibilities: The building owner’s representatives are to facilitate the commissioning process, to help ensure that
corrections are made, and to work with all parties to achieve an optimum product.
General Commissioning Procedure for Economizers October 31, 2001
VI. VERIFICATION - INSTALLATION CHECKLIST:
Instructions: Under each unit write "Y" for yes, "N" for no, "NA" for not applicable, and a number to refer to any needed comments. Identify responsible contractor. If issues or concerns arise, number and note in comment section below.
Criteria for Acceptance: Answers of “Y” (or “NA”, where not relevant) except where other criteria are noted.
Caution: Only qualified personnel familiar with the operation of the installed economizers, and the hazards involved, should adjust, operate, test, and/or service the equipment. The commissioning agent should become familiar with the installation,
operation, and maintenance manuals prior to starting commissioning work. Failure to observe proper safety precautions could
result in damage to equipment, severe bodily injury, and/or loss of life.
Check SSC AHU
1
SSC AHU2
SSC AHU3
PEC AHU1
Comments
General Installation
General appearance good, no apparent damage
Environment clean
Good access for maintenance Access doors close tightly – no leaks
Equipment labels affixed properly
Economizer installed in accordance with manufacturer’s specsand drawings
The installation and location of the economizer are in a neutral
zone of the building (i.e. there are no undo pressure restrictions
or drops that hinder air movement)
Outside air intake is located away from pollutant sources and
exhaust outlets
Damper Installation
Dampers and linkages installed in accordance with drawings
Dampers are properly linked, and move in the right directions Linkages have minimum play
Installed dampers match specifications
Dampers move freely without binding and are fully operational.There are no unusual noises when operating.
Actuators are mounted to maximize torque available to the
damper and to maximize linearity between the blade position and the actuator stroke.
Multiple section dampers with multiple actuators need to haveidentical actuators and linkages to make each section’scharacteristics consistent.
Blade lengths of 48 inches or less are desirable, to reduce flutter
and improve sealing.
Dampers close tightly
Dampers are lubricated. Vertical blades have thrust bearings.
Outside air and return air dampers mounted to promote thoroughmixing of the two airstreams prior to entering coils
Dampers are pointing in the direction that facilitates efficient
General Commissioning Procedure for Economizers October 31, 2001
VII. VERIFICATION - CONTROLS SENSOR CALIBRATION CHECKS:
Instructions: For each sensor listed below, collect the following information:
1. Instrument description/identification
2. Manufacturer’s calibration requirements
3. Copy of the most recent calibration certificates
4. Date of most recent calibration and the calibration data
5. Description of the calibration procedure
Installation: Check that all sensor installations and locations are correct, in order to attain an accurate measurement of the
process. Make sure that they are installed out of direct sunlight, and in the ductwork where the process is mixed and uniform.
Sensor elements should not touch any surfaces. The outdoor air sensor should be located away from the economizer inlet or
exhaust, so that it is not affected by natural drafts when the AHU is off. If sensor location is improper, explain in comments, and have it relocated. Verify that sensors with shielded cable, are grounded only at one end. It is not necessary to repeat any full
calibration procedure, but we recommend that through-system calibration checks be made, as follows:
Differential paired sensors. For sensor pairs that are used to determine a temperature or pressure difference, place both sensors
into a uniform temperature bath or expose them to the same pressure. Make sure that they are reading within 0.2°F of eachother for temperature and within a tolerance equal to 2% (of the reading) of each other for pressure. Tolerances for critical
applications may be tighter.
Sensors. Take a reading of the process with a calibrated test instrument close to the site sensor. Verify that the readings are
within the tolerances in the table below. If not, install an offset in the BAS, recalibrate, or replace the sensor. If a second
instrument cannot be installed to take a second reading, remove the sensor and subject it to a temperature bath or pressure
source along with a calibrated sensor, and compare the readings. Record the readings in the table below.Criteria for Acceptance: Temperature and pressure sensors should agree with the calibrated instrument within the tolerances
listed below.
CONTROLTYPE
CAL
SENSOR LOCATION
EMS
SENSOR LOCATION.
IS IT
OKAY?
EMS
MEASUREDVALUE
CALIBRATION
SENSOR VALUE
DIFFERENCE ACCEPTABLE
DIFFERENCE
ACCEPTABLE? /
COMMENTS
Outdoor air temp
SF(.5F),Sac(1F)
Mixed air
temp
1F
Return air
temp
SF(.5F),Sac(2F)
Filter
Differential
Pressure
0.2 inH2O
Comments on Calibration Items (add more sheets if needed):
General Commissioning Procedure for Economizers October 31, 2001
VIII. VERIFICATION - BALANCE REPORT CHECKS:
Instructions: Compare the maximum supply air flow (outside air damper open) documented in the TAB report with the design flow specifications for the economizer dampers. From the TAB report, record the minimum outside air flow when the outside air
damper is at its minimum position with both the supply fan operating at full and at minimum. Compare TAB report flows with
economizer specifications and with the HVAC system design specifications.
Criteria for Acceptance: Test and balance report outside air flows must meet the following criteria: the measured flow must
be greater than the specified flow, and less than 110% of the specified flow. Also, the measured flows must be less than the
damper design maximum flows.
Check Measured Flow
(from TAB)
Specificationand Damper
Design Flows
% Diff Acceptable?
Maximum outside air flow with outside air damper full
open, 100% supply air flow
Minimum outside air flow with outside air damper at minimum and supply fan at 100%
Minimum outside air flow with outside air damper at
minimum and supply fan at minimum RPM
Test and balance report is verified to be in agreement with economizer design specifications? ___ YES ___ NO
Test and balance report is verified to be in agreement with system minimum outside air design specifications?
General Commissioning Procedure for Economizers October 31, 2001
IX. VERIFICATION - OPERATIONAL CHECKS – 1) EXERCISE DAMPERS:
Instructions: These verification checks augment the manufacturer’s instructions. These checks are done prior to functional testing, which are performed while the system is operating normally. Fill in the appropriate values if other information is
requested, such as damper position (%) or temperature. Identify responsible contractor.
Damper Stroke Check This test is to verify that the dampers can operate throughout their full expected range, and that the damper position matches the
position called for in the BAS. Follow the steps in the table below for each damper and economizer.
Criteria for Acceptance: Answers of “Y” (or “NA”, where not relevant) except where other criteria are noted.
Caution: Only qualified personnel familiar with the operation of the installed air handler, and the hazards involved, should
adjust, operate, test, and/or service the equipment. The commissioning agent should become familiar with the installation,
operation, and maintenance manuals prior to starting commissioning work. Failure to observe proper safety precautions could
result in damage to equipment, severe bodily injury, and/or loss of life.
Enter “Y”, “N”, “NA”, or data as requested. Enter comment or note number if deficient.
Check Equipment-> SSC AHU 1
SSC AHU2
SSC AHU3
PEC AHU1
Contractor
Value/ Comments
Air handler fans are off.
Command outside air damper to 100% open.
Is outside air damper fully open?
Is outside air damper position indicator pointing to 100%.
Make sure that the scale is labeled to indicate the 100% position.
Is exhaust air damper fully open?
Is exhaust air damper position indicator pointing to 100%.
Make sure that the scale is labeled to indicate the 100% position.
Is return air damper fully closed? Is return air damper position indicator pointing to 0%.
Make sure that the scale is labeled to indicate the 0% position.
Command outside air damper to 0% open.
Is outside air damper fully closed?
Is outside air damper position indicator pointing to 0%.
Make sure that the scale is labeled to indicate the 0% position.
Is exhaust air damper fully closed?
Is exhaust air damper position indicator pointing to 0%.
Make sure that the scale is labeled to indicate the 0% position.
Is return air damper fully open?
Is return air damper position indicator pointing to 100%. Make sure that the scale is labeled to indicate the 100% position.
Command outside air damper to its minimum operating position.
Is outside air damper at 20% (as specified)?
Is outside air damper position indicator pointing to 20%.
Make sure that the scale is labeled to indicate the 20% position.
Is exhaust air damper at 20% open?
Is exhaust air damper position indicator pointing to 20%.
General Commissioning Procedure for Economizers October 31, 2001
Make sure that the scale is labeled to indicate the 20% position.
Is return air damper at 80%?
Is return air damper position indicator pointing to 80%.
Make sure that the scale is labeled to indicate the 80% position.
Determine damper opening speed.
Command the outside air damper to 0%Command the outside air damper to 100% open and record the time it takes to fully open. Note any unusual noises or problems.
Record the time it takes for the exhaust damper to open and note any
unusual noises or problems.
Record the time it takes for the return damper to close and note anyunusual noises or problems.
Determine damper closing speed.
Command the outside air damper to 0% open and record the time it takesto fully close. Note any unusual noises or problems.
Record the time it takes for the exhaust damper to close and note anyunusual noises or problems.
Record the time it takes for the return damper to open and note any
unusual noises or problems.
Return outside air damper to its normal position.
The checklist items are all successfully completed for given trade. ___ YES ___ NO
Comments on Operational Checks (add more sheets if needed):
General Commissioning Procedure for Economizers October 31, 2001
IX. VERIFICATION - OPERATIONAL CHECKS – 2) FIRE ALARM ECONOMIZER DAMPER
POSITIONS:
Instructions: These verification checks augment the manufacturer’s instructions. These checks are done prior to functional
testing, which are performed while the system is operating normally. Fill in the appropriate values if other information is
requested, such as damper position (%) or temperature. Identify responsible contractor.
Check Damper Response to a Fire/Smoke Alarm
This test is to verify that the dampers respond properly to a fire or smoke alarm. Follow the steps in the table below for eacheconomizer.
Criteria for Acceptance: Answers of “Y” (or “NA”, where not relevant) except where other criteria are noted.
Caution: Only qualified personnel familiar with the operation of the installed air handler, and the hazards involved, should
adjust, operate, test, and/or service the equipment. The commissioning agent should become familiar with the installation,
operation, and maintenance manuals prior to starting commissioning work. Failure to observe proper safety precautions could result in damage to equipment, severe bodily injury, and/or loss of life.
Enter “Y”, “N”, “NA”, or data as requested. Enter comment or note number if deficient.Check Equipment-> SSC
AHU 1
SSC
AHU2
SSC
AHU3
PEC
AHU1
Contrac
tor
Value/
Comments
Verify that the air handler fans are off.
Command the outside air damper to 100% open. The exhaust damper
should be full open and the return damper should be closed.
Set the fire/smoke detection system input signal to ON.
Does the outside air damper close completely?
Does the return air damper close completely?
Does the exhaust air damper close completely?
Reset the fire/smoke detector input signal to OFF.
Do all dampers return to their normal position?
The checklist items are all successfully completed for given trade. ___ YES ___ NO
Comments on Operational Checks (add more sheets if needed):
General Commissioning Procedure for Economizers October 31, 2001
IX. VERIFICATION - OPERATIONAL CHECKS – 3) ECONOMIZER MODE CHECKS
Instructions: These verification checks augment the manufacturer’s instructions. These checks are done prior to functional testing, which are performed while the system is operating normally. Fill in the appropriate values if other information is
requested, such as damper position (%) or temperature. Identify responsible contractor.
Check Economizer Damper Responses in Different Operating ModesThis test is to verify that the dampers respond properly to various input conditions in different operating modes. Follow the
steps in the table below for each economizer.
Criteria for Acceptance: Answers of “Y” (or “NA”, where not relevant) except where other criteria are noted.
Caution: Only qualified personnel familiar with the operation of the installed air handler, and the hazards involved, should adjust, operate, test, and/or service the equipment. The commissioning agent should become familiar with the installation,
operation, and maintenance manuals prior to starting commissioning work. Failure to observe proper safety precautions could
result in damage to equipment, severe bodily injury, and/or loss of life.
Enter “Y”, “N”, “NA”, or data as requested. Enter comment or note number if deficient.
Check Equipment-> SSC AHU 1
SSC AHU2
SSC AHU3
PEC AHU1
Contractor
Value/ Comments
Disconnect power to supply and exhaust fans to make sure that they do not turn on throughout the following tests.
Set BAS to Unoccupied (Fan Off) Mode
Verify that outside air damper is closed.
Verify that return air damper is open.
Verify that exhaust air damper is closed.
Set BAS to warm-up mode.
Outside and exhaust air dampers closed?
Return air damper open?
Set BAS to cool-down mode.
Set outside air temp to 65F
Outside and exhaust air dampers are full open?
Return air damper is closed?
Set outside air temp to 75F.
Outside damper is at minimum and exhaust damper is closed?
Return air damper is full open?
Set BAS to Occupied Mode
(For the SSC) Set outside air temp to 3F less than the warmest zonetemperature.
(For the PEC) Set the outside air temp to 71F or 1F less than the return
air temp, whichever is less.
Verify that outside air damper is full open.
Verify that return air damper is closed.
Verify that exhaust air damper is full open.
(For the SSC) Set outside air temp to 1.5F less than the warmest zonetemp
(For the PEC) Set the outside air temperature to 73F.
General Commissioning Procedure for Economizers October 31, 2001
X. FUNCTIONAL CHECKS – FORCED RESPONSE AND SEQUENCE OF OPERATION
TESTING - FANS ON/OFF, MORNING COOL-DOWN OR WARM-UP, NORMAL OPERATING
MODES, FIRE/SMOKE ALARM, FREEZE PROTECTION
The functional tests that follow include forced response tests and sequence of operation tests. Protocols for operational
trend tests follow.General Instructions: The following sections are a series of field tests that are intended to verify that the economizer, as
installed, operates as it was intended to operate by the designer. In general, these tests are best done with the building
unoccupied or lightly occupied. Environmental conditions will be affected. If that is not possible, the commissioning agent must devise tests that are not intrusive. Some tests may involve trending normal operation over a long enough period to observe the
conditions and modes of operation desired.
Attach to this form all relevant field data, monitored data, graphs, trend logs, and so forth. Annotate any data and graphs so that
it is clear what the data are proving. EMS trend logs of EMS outputs, program print-outs, or schedule and setpoint print-outsare not acceptable as proof of operation, unless the information is first verified to be accurate and documentation is attached.
Trend logs of sensor inputs to the EMS are acceptable. If you were not able to complete a test, explain in a comment.
Instructions: These functional checks augment the manufacturer’s instructions, and are to be performed when the system is
operational. Fill in the appropriate values if other information is requested, such as damper position (%) or temperature. Identify responsible contractor.
Check Economizer Damper Responses when the Fans are Turned On and Off, then during Morning Cool-down and Warm-
up, then during Normal Occupied Operating Modes
These tests are to verify that the dampers respond properly to various input conditions in different operating modes. Follow the steps in the table below for each economizer.
Criteria for Acceptance: Answers of “Y” (or “NA”, where not relevant) except where other criteria are noted.
Caution: Only qualified personnel familiar with the operation of the installed air handler, and the hazards involved, should
adjust, operate, test, and/or service the equipment. The commissioning agent should become familiar with the installation,
operation, and maintenance manuals prior to starting commissioning work. Failure to observe proper safety precautions could
result in damage to equipment, severe bodily injury, and/or loss of life.
Enter “Y”, “N”, “NA”, or data as requested. Enter comment or note number if deficient.
Check Equipment-> SSC
AHU 1
SSC
AHU2
SSC
AHU3
PEC
AHU1
Contrac
tor
Value/
Comments
Make sure that the AHU is ready for functional testing.
Verify stable operation of the AHU and fans before commissioning.
Set BAS to Unoccupied (Fan Off) Mode
Are the supply and exhaust fans off?
Verify that outside air damper is closed.
Verify that return air damper is open.
Verify that exhaust air damper is closed.
Set BAS to Occupied mode to turn the fans back on.
Verify that the outside and exhaust air dampers (or the return air dampers) are open before the fans start.
General Commissioning Procedure for Economizers October 31, 2001
XI. FUNCTIONAL TESTS - ECONOMIZER PERFORMANCE TEST
Instructions: This functional/performance test augments the manufacturer’s instructions, and is to be performed when the system is operational. Fill in the appropriate values if other information is requested, such as damper position (%) or
temperature. Identify responsible contractor.
Criteria for Acceptance: Answers of “Y” (or “NA”, where not relevant) except where other criteria are noted.
Caution: Only qualified personnel familiar with the operation of the installed air handler, and the hazards involved, should
adjust, operate, test, and/or service the equipment. The commissioning agent should become familiar with the installation,
operation, and maintenance manuals prior to starting commissioning work. Failure to observe proper safety precautions could
result in damage to equipment, severe bodily injury, and/or loss of life.
Check Equipment-> SSC AHU 1
SSC AHU2
SSC AHU3
PEC AHU1
Contractor
Value/
Comments
Mixing Box Performance Test
Perform the following stratification test in cold weather. The outside air temperature should be below 40°F and the outside air damper should be
at its minimum opening. Repeat the measurements during minimum and maximum supply air flow rate conditions.
Measure the air temperature profile upstream of the filter. Take a
temperature measurement at the center of each square yard of filter area.
Record the mixed air temperature from the ECMS.
Determine the difference between the minimum and maximumtemperatures.
Is the difference between the minimum and maximum temperatures lessthan 5°F?
Average all of the temperatures for each profile.
Is the difference between the ECMS mixed air temperature and the
General Commissioning Procedure for Economizers October 31, 2001
XII. FUNCTIONAL TESTS - ECONOMIZER OPERATIONAL TREND TEST
Test Procedure: Trends are useful for verifying that the economizer is operating properly when the commissioner cannot be present (such as
evenings, weekends, or extended periods of time). Following is a test procedure that will help verify proper operation of the economizers under
normal system control. Trend graphs are produced which can be used to check that sequences of operation are followed. Economizer
temperatures will be logged for about two weeks. Plots will indicate if the AHU is scheduled correctly and if the economizer dampers are functioning properly. Follow the steps below for each economizer.
Criteria for Acceptance: Items #1 - 12 require answers of “Y” (or “NA”, where relevant) except where other criteria are noted.
Check Equipment-> SSC AHU
1
SSC AHU2
SSC AHU3
PEC AHU1
Contractor
Value/
Comments
Set up EMS trends or install temperature data logging equipment for the following measurements:
Supply Air Temperature – downstream of cooling coil, where air streamis well mixed
Mixed Air Temperature – as far downstream from the mixing dampers as possible without being too close to the cooling coils. A multipoint probe
may be useful for more accurate measurements.
Return Air Temperature – upstream of the return air dampersOutside Air Temperature – place in a protected location near the outsideair grill, away from direct sunlight. If it must be placed in direct
sunlight, shield the sensor with aluminum foil, allowing air to flowaround the sensor, without touching the sensor.
Fasten the temperature sensors securely, and do not allow the sensors to
touch any surfaces.
Collect temperature data (and a timestamp) for a two-week period, whilethe HVAC system is in normal use. Try to capture a period of time with a
wide swing in operating conditions, or outside air temperatures. Storeinstantaneous data at 5-minute intervals.
Download all data into a spreadsheet, and line up all of the data with time.
Use a program such as PG&E’s Universal Translator (UT) if you need help lining up the data.
Plot all four temperatures versus time. Does the plot demonstrate the
following:
Hours of operation are limited to occupied building hours plus an hour or two before building occupancy.
With the AHU is running, does the mixed air temperature track theoutside air temperature when the outside air temperature is between the
supply air temperature and the return air temperature?
When the outside air temperature is above the return air temperature,
does the mixed air temperature track the return air temperature plus a few degrees (due to minimum outside air flow entering the air handler)?
When the outside air temperature is below the minimum supply air temperature set point, does the mixed air temperature stay close to theminimum supply air temperature set point.
Notes to Operational Trend Test:
1 Attach the time plots to this test form to document your test results.
General Commissioning Procedure for Economizers October 31, 2001
XIII. FUNCTIONAL TESTS - M&V SAVINGS CALCULATION USING PERFORMANCE
TRENDING TESTS
Introduction: The following procedure should be used to estimate the savings due to improvements in economizer
performance. It follows ASHRAE’s retrofit isolation approach for determining M&V savings. The assumption is that other commissioning efforts do not affect the economizer’s performance or our estimate of savings. The improvements could come
from a commissioning effort on new or old equipment or from repair, replacement, or retrofit of existing equipment.
Measurements of pre- and post-retrofit data will be needed, in order to characterize the economizer’s performance
improvement as a function of outside air temperature. To determine the energy savings, a model of the fan supply air flow as
a function of outside air temperature will also be needed. The following procedure does not yet comply with ASHRAE 14P, since an uncertainty analysis of the results has not been performed, and we do not know if the results fall within the criteria
of the guidelines.
ASHRAE’s criteria for the application of the retrofit isolation approach involves the following steps:
1. Select independent variables and develop model
2. Select and document Baseline conditions
3. Select duration and frequency of monitoring for Baseline and Post Retrofit periods
4. Project Baseline usage to Post Retrofit conditions
1. Set up and collect pre-retrofit performance trend data using the Economizer Operational Trend Test protocol
(above). Collect enough data to be able to model the economizer over as wide a range of ambient temperatures as
possible. We suggest several weeks of data collected during a transitional season, such as spring or fall. Preferred
baseline data would ideally cover a one-year period before the implementation of the ECM (energy conservation
measure), even though this is rarely achieved.
2. After the retrofit is completed, collect the same economizer data as well as supply fan RPM data. Data collected
during a wide range of outside air temperature conditions is preferable. Collect data for at least one month, for useas an estimate of the savings. Collect data for one year for use in determining ESCO payments or utility rebates.
3. Create a model of the “mixed air temperature minus what the MAT should be” versus outside air temperature, for
both pre- and post-retrofit data.
4. Using fan performance curves, estimate the fan flow (in lbs/hour) from the RPM data that was collected during the
post-retrofit period.
5. Create a model of the fan flow as a function of ambient temperature for the post-retrofit period, for when the
building was occupied.
6. If a full year of data is not available, estimate how much energy will be saved from short-term data in a normal year. Load TMY2 data for your site into a spreadsheet, and use the models to predict MAT deviations and supply airflows
using expected ambient temperatures.
7. Filter the ambient temperature data to include only data for when the building is occupied.
8. For each hourly reading of ambient temperature, calculate the energy saved due to the economizer retrofit, using
the following formula:
Energy saved(kWh) = [(MATdev pre – MATdev post ) * Supply Air Flow(lbm /hr) * 0.24 (Btu/lbm*F)] /