DRAFT
STANDARD PROTOCOL FOR MEASUREMENT OF FAN
AND COOLING SAVINGS FROM COMMERCIALSECTOR PACKAGED ROOFTOP AND SPLIT SYSTEM
HVAC UNITS
Submitted to
REGIONAL TECHNICAL FORUM
Submitted by
NEW BUILDINGS INSTITUTE
1601 Broadway Street
Vancouver, Washington
Table of Contents
1. PURPOSE............................................................................................................ 1
2. DEFINITION OF KEY TERMS ..................................................................................... 1
3. ELIGIBLE SYSTEMS AND MEASURES ........................................................................... 2
3.1. Eligible Systems ........................................................................................................... 2
3.2. Eligible Measures ......................................................................................................... 2
4. REQUIRED COMMISSIONING.................................................................................... 2
5. SAMPLING PROCEDURE .......................................................................................... 3
6. SUNSET CRITERIA ................................................................................................. 3
7. REQUIRED KNOWLEDGE AND SKILLS OF PRACTITIONER ................................................... 3
8. DATA COLLECTION REQUIREMENTS ........................................................................... 4
8.1 One Time Site Measurements and Descriptions ............................................................. 4
8.2 Data Logger Measurements .......................................................................................... 5
8.3 Typical Meteorological Year (TMY) Weather Data ......................................................... 8
9. PROVISIONAL DATA COLLECTION REQUIREMENTS ......................................................... 8
10. SAVINGS ESTIMATION STEPS ................................................................................. 8
10.1. Compute Normalized Annual Consumption (NAC) for Pre-and Post-Data Logging
Intervals ............................................................................................................................. 8
11. ESTIMATE OF TYPICAL MEASUREMENT COST ............................................................. 9
12. RELATIONSHIP TO OTHER PROTOCOLS AND GUIDELINES ............................................. 11
13. USER’S GUIDE TO THE SAVINGS CALCULATOR.......................................................... 12
13.1. Analysis Instructions ................................................................................................ 12
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1. Purpose
This protocol establishes the methods by which annual electrical cooling and fan energy use and savings
(kWh) can be estimated for a commercial packaged rooftop units (RTU) and split systems that provide
heating, ventilating and air conditioning (HVAC). Cooling and fan energy savings are estimated by
calculating annualized energy use estimates from system energy use and temperature measurements
before the efficiency measures are installed and after the installation of eligible efficiency measures.
The protocol specifies minimum acceptable data collection requirements and methods. The allowable
method is described for how the required data is used to calculate estimated annualized energy use of
eligible systems before and after the installation of the measures and the calculating resulting savings.
For some data elements, alternative eligible sources of data are defined. Normalized Annual
Consumption (NAC) is computed using an Excel workbook Savings Calculator that accompanies this
document to provide standardized application of the savings estimation methods.
2. Definition of Key Terms
Baseline. This modifier, as in baseline control strategy refers to the control strategy for the period prior
to the RTU upgrade. Baseline is the type and condition of the RTU, operations schedules, building
occupancy rates or type, or other site or system conditions affecting fan and cooling energy use prior to
program intervention.
Pre. This modifier, as in pre-measurement period, refers to the period prior to the RTU qualified retrofit,
maintenance or repair measures.
Post. This modifier, as in post-weekday hourly load factors, refers to the weekday hourly load factors for
the period after the RTU qualified retrofit, maintenance or repair measures are installed and fully
commissioned.
Commissioning. This is the process of testing and adjusting to ensure that 1) the data logging
equipment is operating as required, and that 2) the adjustments or repairs made to the RTU are
operating according to design intent.
RTU Repair/Retrofit. The RTU must be a packaged air conditioning unit including a supply fan. Since
the protocol estimates annual fan and cooling savings, the source of heat is not an eligibility criterion.
Section 3 describes the eligible measures for repair and/or retrofit.
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3. Eligible Systems and Measures
3.1. ELIGIBLE SYSTEMS
Use of this protocol is limited to the use of the following commercial sector heating, ventilating and air
conditioning systems:

Rooftop package systems and split systems that provide cooling and ventilation with constant
speed supply fans and constant or multi speed compressors.

Heat pump systems in the cooling and ventilation modes only, with the heating mode turned off
during the monitoring period.
3.2. ELIGIBLE MEASURES
Eligible RTU efficiency measures include physical repairs, operational repairs, maintenance or
equipment upgrade. Eligible measures may include a single measure or a package of measures. Where
more than one measure is installed this protocol estimates savings for the package of measures. The
RTU efficiency measures are described as follows with typical examples of efficiency measure actions.

Physical repair measures include: economizer dampers, linkages or controls repair, airflow
adjustment, refrigeration cycle adjustment, drive-related adjustments, and temperature sensor
replacement.

Operational repair measures include: appropriate schedule and temperature set point
adjustments, economizer sequence of control adjustment.

Maintenance measures include: deep coil cleaning, filter replacement, refrigerant charge
restoration

Equipment upgrade measures include thermostat replacement (upgrade to 2-stage),
economizer installation, compressor replacement, fan pulley or bearing replacement.
4. Required Commissioning
Commissioning of the eligible measures requires documentation as to which eligible measures were
applied to the HVAC system components inside and on the roof of the building. The style and format of
the documentation is at the discretion of the program operator and evaluator. Electronic
documentation is recommended to help support overall program evaluation.
The installation of an RTU measure includes a “good practice” verification check that serves as
commissioning of that measure from the perspective of the HVAC technician. Beyond the verification
check and documentation, no other measure specific commissioning is required.
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5. Sampling Procedure
A sampling procedure is not required.
6. Sunset Criteria
This Protocol shall be in place until such time that a revision is proposed and adopted or not longer than
five years (March 13, 2017) from the date it was approved by the Regional Technical Forum, whichever
comes first.
7. Required Knowledge and Skills of Practitioner
The practitioner, who has lead responsibility for applying this protocol to an RTU, has to understand the
basic requirements in order to assure the accuracy and reliability of the data acquisition and analysis.
The practitioner must have a full understanding of the following:
 Appropriate electrical and related safety procedures for work involving an RTU and the
measurement equipment used in this protocol. This includes an understanding of three-phase
electric power measurements.
 The protocol and the accompanying Microsoft™ Excel-based spreadsheet Normal Annualized
Consumption and Savings Calculator. This includes background for the theoretical and statistical
basis for the measurement as provided in the protocol.
The practitioner must also be able to successfully perform the following tasks:
 Identify by inspection: the control system or thermostat controlling the RTU, the number of cooling
stages, control settings including all schedules and temperature set points.
 Select appropriate data logging equipment from any one of multiple suppliers on the market with
appropriate data storage capacity determined by the data acquisition period for pre-post
maintenance intervals actually planned for the evaluation.
 As required by state electrical code, supervise a licensed electrician in taking a series of spot
measurements of true power at the electrical panel and properly installing the data logging
equipment.
 Monitoring and verifying the data logger data output.
 Ability to interpret the results.
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8. Data Collection Requirements
This protocol, applied to the pre- and post-retrofit RTU data, will estimate the savings impacts of the
RTU upgrade and any other changes that have occurred between the pre- and post- measurement
periods. The energy usage estimated by this protocol will reflect the occupancy patterns that prevail
during the metering period. Therefore, it is important at the outset to verify that the site is being used
as it typically would in regular year round occupancy. It is also important for the accuracy of the savings
measurements that the occupancy activity during the pre- measurement period be the approximately
same as during the post- measurement period. This initial occupancy assessment is a judgment call; it is
not intended to be precise, but it is intended to identify obvious disruptive site conditions such as: “the
office is not used” or “the site is being renovated.”
The data collection for this protocol consists of three principal parts discussed in Sections 8.1, 8.2, and
8.3.
8.1 ONE TIME SITE MEASUREMENTS AND DESCRIPTIONS
The following one time site measurements and check out activities are necessary to provide a
minimum description of the site and to verify proper operation of the data logging system.
Minimum site information provides key market data for repair/retrofit/replace program design as well
as evaluation and it can help calibrate energy models. This information consists of the building on
which the RTU is operated as well as basic nameplate information for the individual unit.
 Building basic description: Location, occupancy type, number of stories between RTU and served
space and any unusual features that may affect RTU energy use.
o Baseline control strategy: RTU thermostat set points, number of stages and schedule.
o RTU description: Make, model, serial number, nominal tons, number of compressor stages,
nominal age, voltage and number of phases.
o Fan motor horsepower: Obtained from the motor nameplate or product invoice.
o Floor Area Served: Estimate of the floor area served by the unit.
Proper operation of the data logging system requires a comprehensive checkout before the system can
be considered operational. The checkout requirement includes at least the following:
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
The data logger, its communications mode and memory storage must be tested.

The full data set should be read out after the first few hours of metering operation to verify that
the integrity and accuracy of the logged data and the data storage system.

True power measurement and recording interval should be not longer than every three minutes.

Spot check power measurements should be made for the fan-only mode and at least one
compressor mode to verify and confirm true power measurement accuracy. The spot check
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measurements should allow the unit time to come to a steady state power level (often several
minutes). The spot measurements are then compared to the corresponding logged data to verify
the logger operation. The fan power spot measurement data of fan-only power should be
retained, as it is a required input to the Savings Calculator.

Where outdoor temperature is measured to provide average hourly temperature intervals,
temperature measurement must be verified by spot temperature measurement using a calibrated
second temperature measurement device.
8.2

DATA LOGGER MEASUREMENTS
RTU true power. For this protocol, true power is the product of instantaneous current and
voltage measurement using typical true power transducer devices. Log pre- and post- RTU true
power including the supply fan and all auxiliaries. In some jurisdictions, a licensed electrician may
be required to install true power measurement equipment. In this event, the practitioner will
supervise the installation. A three-minute interval is the longest interval for the true power
measurement. The true power measurement should be the integrated true power measurement
(energy) during each measurement interval. True power measurements should be taken at the
electric service to the unit at the shut off switch junction box or at the primary breaker for the
unit. In the case of split systems, the measurements should be on the entire electric service to the
compressor and the entire electric service for the air handling section. Split system
measurements for the compressor and air handler are summed for system true power
measurements. All measurements should be upstream of any line current control devices such as
variable speed controls.

Outdoor air temperature. Obtain hourly outside air, dry bulb temperature from a nearby,
representative weather station, especially a National Oceanic and Atmospheric Administration
(NOAA) station. Monitoring costs can be reduced by using local weather station data. If, in the
judgment of the practitioner, the nearby weather station is not representative due to distance,
altitude, or unusual local geographic condition, the outside air temperature must be collected at
the RTU site at the same data-logging interval as the true power, not more than three-minute
intervals. For on-site measurement, the temperature sensor should be mounted on the roof
near the RTU, in a location that is shaded most of the day, and at least 18 inches above the roof
deck. The outside air sensor must be installed inside a passively vented radiation shield.

Supply Air Temperature. This temperature measurement is optional because it is not necessary
to calculate RTU energy use and savings. The Savings Calculator will work without supply air
temperature data inputs. However, the supply air temperature is a monitoring upgrade that is
useful for diagnostic purposes because it can be used to classify operating modes, to verify
economizer operation, and to estimate the minimum outside air fraction. If the supply air
temperature is collected, the temperature data should be collected at the same measurement
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interval as for true power. When a supply air temperature measurement is made, the
temperature sensor should be placed in the supply air plenum. The sensor must be kept from
touching the walls of the supply air plenum. The Savings Calculator will accept and process the
supply air temperature data, if it is available.

Selection of Pre- and Post-Retrofit Measurement Periods. Accurate estimate of fan and cooling
energy use requires specific measurement periods before and after the retrofit activity. Pre- and
post-measurement as close to before and after RTU retrofit provide higher confidence that the fan
and cooling savings measured resulted from the retrofit measures. Pre- and post-measurement
periods must each consist of four weeks occurring within a measurement windows described in the
three methods below. These measurement windows deliberately do not include the peak midsummer period. This precludes monitoring periods that include the first week in July through the
end of July because the period includes minimal economizer operation and because the high
temperature data is too closely clustered to give adequate statistical resolution. There are three
measurement period methods to choose from to meet this requirement. The first method, the
summer retrofit method is preferred because it is easier to manage and less expensive to
implement. The other methods included in this protocol will work, but generally at higher cost and
additional effort. They are included here order to accommodate custom experimental designs.
1. Summer Retrofit Interval Method. This is the preferred and simplest approach with a
flexible retrofit period of at least four weeks centered on the month of July. The four-week
pre-retrofit measurement period should start no earlier than mid-May, and it should end no
later than the last week of June. The four-week post-retrofit measurement shall start no
earlier than the first week of August, and it should end no later than the third week of
September. The retrofit window consists of about four weeks, between the first week in
July and the first week of August. Even though this is the most active customer repair
period for most HVAC contractors, this four-week period is intended to provide flexibility for
scheduling the repair work. If the repair is outside these seasonal parameters, or not
completed between the pre- and post-measurement periods allowed under this period, the
results do not comply with this protocol.
2. Winter Retrofit Interval Method. This alternate measurement period allows the retrofit to
be done in the winter. The four-week pre-retrofit measurement period should start no
earlier than the first week of August and end no later than the third week of September.
The four-week post-retrofit measurement should begin no earlier than the third week of
May, and it should end no later than the last week of June. The winter retrofit window is
more flexible, anytime between October and March. It is preferable that the retrofit occurs
within 2 months of the start of the post period.
The winter retrofit interval method requires additional documentation of any fundamental
condition changes, other than retrofit measure installation, that may have occurred during
the winter retrofit interval. For this method to comply with the protocol, it should be
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verified that similar conditions exist during both the pre- and post- periods. Such conditions
include: same business occupying zone served with similar occupancy hours, same RTU
conditions (unless affected by programmatic measures) such as manual thermostat settings,
dampers not being forced closed or covered over, unit, and unit operation with no changes
in the zone served such as ductwork extended to new zones or rooms eliminated.
3. Eight-Week Spring or Fall Method. This method allows the pre-and post-data to be collected
in one eight week period in the spring or fall. It allows for data collection on measures that
are permanent and that may be turned on and off for alternate weeks. For this approach,
the measurement period should be at least eight (8) weeks. The spring data collection
period should start no earlier than the fourth week of April and end no later than the first
week of July. The fall data collection should start no earlier than the first week of August
and end no later than the second week of October.
This eight week metering option is clearly restricted to retrofit measures that may be turned
on and off on a weekly basis. Measures allowed for turning on and off include primarily
replacement controls. Measures that include permanent changes to the system such as
damper linkage repairs, refrigerant charge, coil cleaning, damper seals, cannot be
accommodated in this approach.
Figure 1 provides examples that meet the requirements listed above: Note that the summer retrofit
interval B and the winter retrofit intervals considerably lengthen the retrofit window by sliding the
pre- and post-retrofit metering periods. While such a metering schedule may give adequate results,
it may cost more because the extended time between the pre-and post-metering periods may
require more data management, acquisition, cleaning, and analysis.
Figure 1: RTU Protocol Field Monitoring Options
RTU Savings Protocol Monitoring Period Options
Pre Monitoring Period
Post Monitoring Period
Summer Retrofit
Interval (A)
R
R
R
R
R
Summer Retrofit
Interval (B)
R
R
R
R
R
R
R
R
R
R
Winter Retrofit
Interval*
R
R
R
Instantaneous
Interval (A)
R
R
R
R
Apr
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Apr
R
R
R
R
Instantaneous
Interval (B)
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R Retrofit Installation
May
May
Jun
R
R
Jun
Jul
Jul
Aug
Aug
Aug
26
10
24
7
21
5
19
2
16
30
* For Winter Retrofit Interval option, the pre-monitoring period occurs the previous year
For all options, avoid monitoring in the month of July
Sep
Sep
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8.3
TYPICAL METEOROLOGICAL YEAR (TMY) WEATHER DATA
The estimate of annual energy use by the Savings Calculator requires the typical hourly outside air
temperatures for each hour of the year as inputs. These typical hourly air temperatures are provided in
the form of TMY data that is available for most localities in the United States. The Savings Calculator is
set up to readily use TMY3 data from PNW TMY3 weather data files that have been provided.
However, other sets of ambient outdoor temperature data could be used as inputs to the Savings
Calculator, as long as the data set includes a full year of time stamped hourly data and follows the
Savings Calculator input format using hourly timestamps with associated dry bulb ambient
temperatures.
If the measurement practitioner believes that the nearest TMY3 site does not closely represent site
weather conditions, actual site weather data can be collected and used for the annualization, as long as
a full year of hourly temperatures are available in the proper format.
9. Provisional Data Collection Requirements
Provisional data collection requirements do not apply.
10. Savings Estimation Steps
Annual energy savings are estimated using the Savings Calculator that accompanies this protocol.
10.1. COMPUTE NORMALIZED ANNUAL CONSUMPTION (NAC) FOR PRE-AND POST-DATA
LOGGING INTERVALS
 Data Preparation.
The data interval for a single NAC measurement will consist of at least 28 days of
logged power and temperature, with a three-minute data-logging interval. Data of this sort may
have gaps and out of bounds values that need to be removed or resolved before the data is used in
the Savings Calculator. The details of this data management are common to any data logging effort
and are beyond the scope of this protocol to specify. In the Savings Calculator, the data must start
at 00:00 hour of the first day. Any days with significant missing data should be eliminated so that
only full days are used. Gaps in the time sequence caused by missing whole days are not a
significant problem. If only a few minutes of data are missing or corrupt, then replace with good
data from the prior minutes. The Savings Calculator has features to help the user eliminate
incomplete daily data and the Savings Calculator instructions provide information on the deselecting days, and what to do on each worksheet.
 Energy Savings Calculation Sequence.
To estimate savings, the Savings Calculator will be used
twice, separately characterizing the pre- and post-annual energy use. The measurement of the pre-
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retrofit annual energy use, NAC 1, is derived from the data collected for the pre-retrofit period. The
post-retrofit normal annual energy use, NAC 2, is derived from the data collected in the postretrofit monitoring period. The annual energy savings for the monitored site is then NAC 1 minus
NAC 2.
 Electric Load Shape Calculation Sequence.
This sequence distributes the daily energy use into
hours of use such that the total energy use predicted for each hour of the day will reconcile with the
metered data. This process predicts the average energy use for the hour by daytype and season
very accurately, though it will not predict the energy use for a particular hour exactly. A summary of
the process:
o Energy-weighted average hourly load factors are calculated from hourly and sub-hourly
minute data over the baseline and post measurement periods, and for fan-only and
compressor operations and for weekday and weekend operations. This occurs in the Savings
Calculator in the Hourly Load tab. The annual hourly is developed on the Annual tab.
o The normalized load factors are applied to parse the temperature-correlated energy data to
8760-hour bins based on the TMY data and the annualization functions of the Savings
Calculator.
o This is done separately for the fan and compressor components for weekday and weekend
periods for both pre- and post-retrofit periods.
 Demand Savings Calculation Sequence.
In addition to the NAC savings output, the Savings
Calculator produces a reasonably precise estimate of maximum demand versus temperature.
Currently, this demand function is not used because the primary measurement is focused on energy
consumption. It can however, be used to report demand impacts and examine performance,
including determining if the unit is oversized, and if there has been a change in maximum power due
to measure implementation, such as from fan adjustments, charge adjustments, filter replacement,
and condenser coil cleaning.
 RTU Signature and time series operating graphs.
This information is a by-product of the NAC
savings calculation. Review of these graphs provides the operating schedules of the RTU and
provides direct evidence of the operation (or non-operation) of an economizer on the metered unit.
 Supply Air Temperature Measurements.
Supply air temperature does not play a role in estimating
the NAC savings, but it can be used classify operating modes (heating or cooling) in other analysis
that may use the measured data. The immediate use of the supply air temperature is to estimate
the fraction of outside air drawn in by the RTU and the minimum outside air setting of the unit.
11. Estimate of Typical Measurement Cost
Cost profiles for two approaches of metering are presented. Both cost scenarios assume a mature state
of metering experience fully incorporating lessons learned from previous metering activities. The
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calculator is designed to use the information from either of these approaches to develop an annual
savings estimate. The costs of both approaches are dominated by the labor costs. No training costs are
included in this estimate. However, the second approach requires a more qualified practitioner.
The first approach is designed to minimize costs by using site circumstances to lower costs. It assumes
local NOAA hourly weather station data is available instead of site temperature monitoring. A small selfcontained power logger in used in the breaker panel. This approach can be used to meter two, threephase units or three, single-phase units at once. This approach, referred to here as the “expedited
approach,” requires minimal practitioner training, but can only be applied where the circumstances are
suitable.
Table 1: Projected cost for the Expedited Measurement Approach
For two delta wired RTUs in the same breaker panel
Item
Hours
$ / Hour
Rental
Total Cost
500
$500
Equipment
True Power Logger
Power Transducers
Current Transformers
Labor
M&V Practitioner
Travel
Schedule/access
Install
Checkout
Install/Remove Current Logger
Savings Analysis
Electrician/Certified HVAC Tech
Travel/Measurement
Total
Cost/RTU
2
1.5
1
0.5
0.5
1.5
75
125
125
125
125
125
150
188
125
63
63
188
2
125
250
$1,275
$638
Equipment if purchased:
Logger
$1000
Current Transducers (4) $300
Voltage taps (4)
$100
Note: In Table 1, the total cost of the logger and equipment is not used; instead the equipment cost in
this table is considered a “rental” cost that is one third of the total cost on the assumption that the
equipment suite will be reused at least twice more.
The second approach is more comprehensive including collection of rooftop site air temperature and
supply air temperature. This approach, referred to as the “comprehensive approach,” must be used
when there is no local NOAA weather data, where all the metered units are three-phase Y-wired or
where the supply air temperature is required for additional diagnostic information. This approach is
significantly more complex (and flexible) than the expedited approach and requires more practitioner
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skills because it involves setting up a full data logging installation including communications and logger
powering.
Table 2: Projected costs for the Comprehensive Measurement Approach
For three RTUs within 50 feet of each other on a single rooftop.
(Note that Table 2, as in Table 1, a rental cost for logging equipment equal to one third of the total
equipment cost is assigned.)
Item
Hours
$ / Hour
Rental
Total Cost
Equipment
True Power Logger
800
$800
Power Transducers
Current Transformers
Labor
M&V Practitioner
Travel
2
75
150
Scheduling/access
2.5
125
313
Install
5
125
625
Checkout
1
125
125
Install/Remove Current Logger
1.5
125
188
1.5
125
188
4
125
500
Savings Analysis
Electrician/Certified HVAC Tech
Travel/Measurements
Total
$2,888
Cost/RTU
$963
Equipment if purchased:
Logger
$1100
Current Transducers (4)
$300
Temps sensor (4) with shields $350
WattNodes (3)
$750
12. Relationship to Other Protocols and Guidelines
This protocol is related to other published protocols and guidelines, including:
 M&V Guidelines: Measurement and Verification for Federal Energy Projects Version 3.0, U.S.
Department of Energy Federal Energy Management Program. This guideline requires both
baseline and post measurements that are required by this protocol.
 Sampling Reference Guide, Bonneville Power Administration.
Relevant to program level impact
evaluation
 Regression Reference Guide, Bonneville Power Administration.
The RTU protocol uses regression
techniques to fit a linear equation to the measurements of average daily true power and average
daily temperature.
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 Additional RTU-related background information is found at the RTF/Rooftop Unit Working Group
website.
13. User’s Guide To The Savings Calculator
13.1. ANALYSIS INSTRUCTIONS
There must be sufficient data for both pre- and post- periods for these calculations to work properly. It
is not possible to give exact criteria for "sufficient data," but the workbook is intended for use with 4
weeks of data in the pre-period and 4 weeks of data in the post-period. It may work with as little as 2
weeks of data in each period. Regardless of the data availability time period, the data in both periods
must include periods of compressor cooling and before starting, you should have your raw data
workbook open, as well as the workbook. Make sure your raw data workbook is not minimized.
The raw data must be organized as shown in both Instruction and CalcsStart tabs of the workbook. RTU
Supply Temperature is not required, but if available, it will be used to help estimate the fan power. Fan
power can also be input during the process.
If supply air temperature (SAT) is not available, that column and header must still be included, even
though the data rows will be blank. Column order is important, but there can be separate columns for
date and time as long as they are the first 2 columns.
If site outside air temperature (OAT) is not available, you can use another tool to download data from an
appropriate site such as other local site data or local NOAA TMY3 data. See the section to the right on
"Historical Site Weather Data."
 Select Data to be Analyzed
When prompted, you will need to select the raw data. After selecting the top row, you can use CtrlShift-Down to select all the data. Then, follow the prompts for the remainder of the calculations.
 Project Dates
After entering the data, you will be prompted for the date the energy savings project started. Enter the
appropriate date, which obviously must be within the time range of data selected. After entering the
start date, you will be prompted for the date the energy savings project was completed. The analysis
will use these two dates to define the pre- and post-periods. Data from between and including the two
input dates will be excluded from the analysis, although it will be included in some charts.
 Fan Power
Next you will be prompted for the baseline fan power. If SAT was included in the data, an initial
estimate of fan power will be provided. You can use the initial estimate or enter a new value. You will
similarly be prompted for the post- period fan power, and again can use an initial estimate if SAT was
included in the data.
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 Select Daytypes
The tool will create a chart showing the average load profiles of estimated RTU Status for each day of
the week. These load profiles will make it easy to determine which days are similar. Similar days should
be combined into a daytype.
To create daytypes, checkboxes for each day of the week are included on the worksheet with the load
profiles of RTU Status. Check the box for each day in the first group of similar days and click the
"Update" button. Any remaining days of the week will be presented in a new set of checkboxes. Again,
check the box for each day in the second group of similar days and click "Update." Continue until all
days have been checked. The tool provides flexibility to have any number of daytypes from 1 (all days of
the week have similar RTU scheduling and operation) to 7 (all days are different) and in any
combination. After all days have been checked and the "Update" button clicked, the processing will
continue.
 Re-Check Fan Power
At this point, the previously input or estimated fan power is used to estimate times when only the fan is
operating. The average power for all these times is calculated for comparison with the previously input
power. The user has the opportunity to change the fan power before proceeding with the rest of the
calculations. This opportunity is present for baseline and post-period fan power estimates.
 Data Summarization and Regression Analysis
The bulk of the processing takes place at this point, without any user intervention. The data is first
aggregated to an hourly level, and charted in both time series and scatter plots. These summarizations
and charts are for the user's benefit in reviewing the data and the analysis; they are not used in the
calculations.
Next the data is aggregated to the daily level and the change point regressions are created that are used
for the savings analysis. Separate pre- and post-regressions are created.
Then the average hourly power for the fan and compressor are estimated for pre- and post. These
"hourly factors" are used to get the load shape of the savings, since the actual savings is based on the
daily aggregations.
Charts of how well the model reproduces the baseline are created. There is a scatter chart of modeled
vs. actual data and a time series chart showing the modeled and actual data vs. time. These comparison
charts are created at both the daily and hourly level of data aggregation.
 Annual Estimates Using TMY3 Data
After the above calculations and charts are complete, you will be prompted to enter the TMY3 weather
for the nearest appropriate site. See the information titled Related Helpful Workbooks in the workbook
Instruction tab for an easy way to obtain TMY3 data for any site in the Northwest. Do not click the
"Continue" button until after the TMY3 data has been entered. When the processing resumes, annual
estimates of energy use for a typical year are created for both the pre- and post-models, at the daily
level. After the calculations at the daily level are complete, the daily estimates and the hourly factors
New Buildings Institute
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are used to estimate the typical use on an hourly basis. The savings are calculated by subtracting the
post period estimated energy use from the pre-period estimated energy use.
 Eliminating Specific Days from the Analysis
Some datasets may have bad or incomplete data on certain days and it may be necessary to eliminate
those days from the analysis. The tool makes it easy to do so, since the individual days can just be
unchecked. However, they need to be unchecked in multiple places.
On each worksheet, just click the down arrow next to the "Date" field. The worksheets have
PivotTables, and the "Date Field" is either in a PageField or a RowField. In either case, just uncheck the
appropriate days. These days will need to be unchecked for each daytype, and pre- and post-period as
presented on each worksheet.
The following table provides additional information on the de-selecting days, and what to do on each
worksheet.
Worksheet
Data
LP_StatusDOW
Daytypes
FanPwrChkPre
FanPwrChkPost
HourlyByPrePost
Change
Priority
None
None
None
None
None
Optional
BaseDailyByDaytype
Required
PostDailyByDaytype
Required
HourlyFactorsBase
Recommended
HourlyFactorsPost
Recommended
DailyModelMonPeriod
Optional
HourlyModelMonPeriod Optional
TMY3daily
TMY3hourly
14
None
None
Changes Needed
None
None
None
None
None
This worksheet is information-only, so the changes can be
made here if the user desires to see the changes on the
graphs.
Deselect the days desired. Do so for each daytype that has
days that should not be included in the analysis.
Deselect the days desired. Do so for each daytype that has
days that should not be included in the analysis.
Changes here will not affect the estimation of the savings,
but could affect the estimated timing of the savings.
Deselect the days for each daytype that has days that
should not be included in the analysis.
Changes here will not affect the estimation of the savings,
but could affect the estimated timing of the savings.
Deselect the days for each daytype that has days that
should not be included in the analysis.
This worksheet is information-only, so the changes can be
made here if the user desires to see the changes on the
graphs.
This worksheet is information-only, so the changes can be
made here if the user desires to see the changes on the
graphs.
None
None
New Buildings Institute