Transcript Draft Standard Protocol for Cooling and Fan Savings from RTUs RTF March 1, 2011

Draft Standard Protocol for
Cooling and Fan Savings
from RTUs
RTF March 1, 2011
RTF-RTUG Time Line
NEEA
2002-2004
• Pilot Field Work
• Inconclusive
Savings
• Identified potential
deadband issues
• Not ripe for
Market
Transformation
RTF
RTF
RTF
Phase I
2004
Phase II
2006-2007
Phase III
2009-2010
• Secondary
Source Review
• Frequency of
Problems
• Scope Next
Phase
• Test Protocol to Measure
Savings
• Large BPA Field Test
• Goal: Deemed, Deemed
Calculation or MV Protocol
• Scope Phase IV
•
•
•
•
•
Lab Testing
Limited Field Test
Honeywell Sensor Redesign
Develop Protocol to Measure Savings
Scope Next Phase
Slide 2
Rooftop Unit Working Group
Time Line
RTF
RTF
Phase IV
2011
Phase V
2012
RTF
RTF
Phase VI
2013
Phase VII
2014
•
•Analyze annual data
• Propose annual savings
estimation methodology
• Propose M&V protocol
• Elements of a regional
Strategic Plan/Roadmap
• New/next generation
technology
• Recommendation to RTF
for next steps
• Expand West Coast
collaboration
• Implement Roadmap
elements
• Deep RTU retrofit
program
•Web-enabled T-stat
approach verified with
2-yr data analysis
• New gen evaporative
• Premium Ventilation
benefit established
• Stronger
regional/national
collaboration
• Identify deep retrofit
•
• Adaptive controls
• Embedded RTU performance
monitoring/FDD specification
• Test deep retrofit options
• Fix DOE2/eQUEST
options
Slide 3
Rooftop Unit Working Group
(End of) Time Line
RTF
Phase XXXIII
2046
• Dx RTU’s illegal
• Evaporative/hybrids, VRF and ground source heat pumps required by law
• Self-replicating neural networks with self-diagnosing, self-regulating, &
self correcting controls on all units
• Bomb proof economizers/controls
• 7-10 year maintenance intervals
• HVAC OEM’s required to provide performance guarantee over product life
• Cherniack Retires
Slide 4
Today

Review Protocol & Calculator

Review issues raised & addressed at RTUG

Staff Recommendation
– Resolve any RTF issues
– Finalize protocol & calculator under proposed
guidelines & template
– Staff to scope task to finalize protocol, test calculator,
compile documentation and conform to format
Slide 5
Regional RTU Overview

Varied programs, participants, utilities and approaches
across the region

Project Goal: Protocol for cooling & fan savings
usable across programs, climates and building types

Collaborative research sponsored by
– BPA, ETO, Avista, Idaho Power, RTF
– Technical analysis by Cadmus, NBI, QuEST,
Stellar Processes, Ecotope & others
Slide 6
It took a village…
Slide 7
The RTUG Process 2010

7 RTUG Subcommittee meetings

Prioritized research needed to develop protocol

Cadmus & NBI doing analytics

Feedback from RTUG Subcommittee

Lots of RTUG participation 20-30 people each
– In- and out-of-region (CA/NE) participation
– Other issues taken up too: DCV, Premium
Ventilation, whole-building approach
Slide 8
The Data
PNW RTU 2008-09 Metered RTUs

Avista = 2 pair side-by-side metered @ 12 months

BPA RTU Pilot = 161 metered, 24 units @ 12 months

Energy Trust of Oregon = 13 metered

Idaho Power = 9 metered @ 12+ months (still going)
>> The nation’s largest, most robust, publicly
available measured RTU data set
http://www.nwcouncil.org/energy/rtf/subcommitt
ees/rtug/2009_rooftop/Default.aspx
Slide 9
Current RTU Savings Research
2010-13/ Web-based T-Stats (Dreamwatts)

BPA 2010 start: 44 RTUs on 3 buildings 24-36
months DA; Cadmus analysis on first 12 months only
with report March 2011

RTF discussion on data analysis for trailing 12-24
months of BPA units

Data available to upload to Regional RTU Database

RTF 2011 start: 3 heat pumps @ 24 months
w/analysis
Slide 10
Results for 2010

Substantial empirical & analytical basis to
estimate savings attributable to RTU measures
– Huge progress has been made!
– Techniques are being used in impact evaluations

Developed protocol & associated calculator
Slide 11
What Did We Find?

Accurate measurements require understanding the
distribution of daily temperatures and proper timing of
metering

Differences between hot east side metering and mild
west side metering

Measurements of average program savings at 90%
confidence/10% precision can be achieved

Buildings exhibit natural changes over a summer:
‘building squirm’

Methodology will pick up any spontaneous building
operations (squirm) in between pre-post- measurement
periods
12
Issue: Highly variable savings
From BPA 2009


Probably not deemable UES
Site-specific savings depend on as-found & program measures
eg: ETO adding economizers to 3-4 ton RTUs
Slide 13
Key Elements Addressed by
Cadmus & NBI & RTUG -1

Protocol issue raised:
–Does a single signature accurately show annual energy
use?

How issue was resolved:
–Tested the signature prediction for 10+ months modeled
data and 10+ months measured data
How issue is expressed in the protocol:
- The protocol is based on a single signature for
annualization
Slide 14
Basic Savings Algorithm
Energy signature based on kWh/day and average daily temp
– Horizontal line = fan energy
– Sloped line = fan + compressor energy
– Balance point = intersection of horizontal and sloped lines
– Use with TMY3 data to annualize energy
Slide 15
Key Elements Addressed by
Cadmus & NBI & RTUG-2

Protocol issue raised:
–Does the duration of metering affect the accuracy of the
prediction?

How issue was resolved:
Data block analysis was done April – October in 1 week
increments @ 10, 15, 21, 28 day intervals
How issue is expressed in the protocol:
- The protocol uses a 4 week measurement interval as
most accurate; early/late summer intervals produce the
same performance estimates within a few percent
Slide 16
Key Elements Addressed by
Cadmus & NBI & RTUG-3

Protocol issue raised:
- Does this method lead to biased predictions?

How issue was resolved:
– Examined statistics from the data block analysis that
showed hot mid-summer data can bias predictions
especially on the East side
How issue is expressed in the protocol:
- The protocol recommends not using data from 1st week
in July through 1st week in August
Slide 17
Key Elements Addressed by
Cadmus & NBI & RTUG-4

Protocol issue raised:
- Use of of site temperature data vs. recorded hourly data
from local weather station data

How issue was resolved:
– Use of local hourly data was successfully tested as
source of the temp data for deriving the energy signature
How issue is expressed in the protocol:
- Protocol recommends use of data from local
source within limits, otherwise use shielded site-based
Slide 18
Key Elements Addressed by
Cadmus & NBI & RTUG-5

Protocol issue raised:
– Sample size for M&V to achieve 90% confidence/10%
precision

How issue was resolved:
– Statistic were analyzed to determine sample sizes
1,000 RTUs:
137
500 RTUs:
129
100 RTUs:
88
How issue is expressed in the protocol:
- The protocol includes a table to guide sample size
Slide 19
Key Elements Addressed by
Cadmus & NBI & RTUG-6

Protocol issue raised:
– Can the annualized protocol be applied to VSD on
compressor/fans or to VRF technology

How issue was resolved:
– No specific work has been done yet, but the approach
could and should be applied; need method to compare
How issue is expressed in the protocol:
- Not currently used in the protocol
Slide 20
Key Elements Addressed by
Cadmus & NBI & RTUG-7

Protocol issue raised:
– How can the field M&V be accomplished at lower cost?

How issue was resolved:
– Used nearby weather station data in lieu of site temp
data; used CT in lieu of true power measurement;
How issue is expressed in the protocol:
- Adjusted protocol to use these inputs
Slide 21
Accurate Savings Estimate –
West/East Sides

Needs shortest possible measurement intervals to avoid building
operation changes

Need 4 week measurement during recommended metering
window to capture sufficient weekend data

Pre-measurement window 3rd wk May through 1st week July

Post-measurement window 2nd wk Aug through 4th wk Sept

Summer data usually shows no baseload in avg daily –needs to
be calculated from minute data

In practice: regressions based hot weather 1st wk July through 1st
wk August can bias annualized predictions due to limited cool
weather data (limited or no economizer use)
Slide 22
Base Load Analysis

Examined for statistical differences in
the base load calculation: calculated
error did not affect sample size

Found differences due to using more
power in winter: heating fan energy
23
Slide 23
Related Non-Protocol Issues
Not Resolved

Longevity of fan and t-stat settings

Air flow issues:
- How to treat negative savings from upgrade to minimum
ventilation or ASHRAE 62.1?
- Programmatic: in field measurement/reset options – use of
DCV as a proxy?
- Building code requirement
- Program benefit-cost issue

Measure life: 6th Plan = 5 years for O&M?
Slide 24
Key Elements of Calculator
•
RTU power by minute; could be from single calibrated CT
•
RTU outside air temperature by hour from site minute data or
hourly local weather station if acceptable
•
RTU supply air temperature by minute; not necessary for
annual usage estimate, but useful for estimating minimum
percent OSA
•
Annual histogram for normal average daily temperature at site
from local TMY data
Slide 25
Key Element: Normalized Annual Output
Calculation of Normalized Annual Consumption
Site Temperature
Histogram
Bin
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
95
100
More
Frequency
0
0
0
2
4
5
26
53
73
42
45
59
36
17
3
0
0
0
0
0
signature information from data tab
week end week day
baseload
23.56719 22.71532
balance t
54.81856 46.68124
slope
1.359394 1.364004
weekend
12.5
17.5
22.5
27.5
32.5
37.5
42.5
47.5
52.5
57.5
62.5
67.5
72.5
77.5
82.5
87.5
92.5
23.56719
23.56719
23.56719
23.56719
23.56719
23.56719
23.56719
23.56719
23.56719
27.21233
34.0093
40.80627
47.60324
54.40021
61.19718
67.99415
74.79112
weekday
22.71532
22.71532
22.71532
22.71532
22.71532
22.71532
22.71532
23.83212
30.65214
37.47216
44.29218
51.1122
57.93222
64.75224
71.57226
78.39228
85.2123
weekly
melded
22.95871
22.95871
22.95871
22.95871
22.95871
22.95871
22.95871
23.75642
28.62787
34.54078
41.35421
48.16765
54.98108
61.79451
68.60795
75.42138
82.23482
Normalized Annual Consumption, NAC >>
annual
bin kWh
0
0
45.91742
91.83484
114.7936
596.9265
1216.812
1734.219
1202.37
1554.335
2439.898
1734.035
934.6784
185.3835
0
0
0
11,851 kWh/yr
Slide 26
Key Observations
Protocol needs graphical data quality review
 Protocol performs annualization &
normalization
 Signature will show economizer operation
changes
 The data should be explicitly segregated by
weekday and definable weekend
 Hourly load shape is available

Slide 27
Summary

Protocol ready for finalization including
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–
–
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–

Resolving any remaining issues
Similar to the 7 protocols under development
Small team with contractor with conforming protocols
Cleaning up calculator
Add ProCost module
Finishing protocol template
Documentation of supporting data & protocol testing
Other conforming details
Bundle up for adoption & publishing
Staff to scope contract approach & budget
Slide 28