PNW RoofTop Unit Working Group - RTUG –
RTU Savings Research ProjectPhase 3
December 15, 2009
RTUG Agenda 12/15/09• 9:30-9:45am - Presentation on expected RTU savings and potential from
the NW Power and Conservation Council’s 6th Power Plan- NW Energy efficiency Alliance Service Assistant Project Update
• 9:45-10:45 Results: Bonneville RTU Savings Research
>> 10:45-11:00 Break
• 11:00-12:00pm Discussion: Bonneville Results
• 12:00-12:15pm Results: Idaho Power RTU Savings Research
>> 12:15-1:15pm Lunch Break - WEB shows agenda; telcomm off line
• 1:15-1:30pm Results: Energy Trust of Oregon RTU Pilot Savings
• 1:30-1:45pm Results: Puget Sound Energy RTU Savings Evaluation
• 1:45-2:00pm Results: AirCare Plus℠ in California
• 2:00-3:30pm Discussion: Next Steps- Use of the data for additional analysesOptions for Assessing Expected Value SavingsRecommendations to the RTF - January 5, 2010
PNW Regional Summary 226 RTUs Serviced/Measured!
• Avista = 6 pairs to be metered
• Bonneville Power Administration RTU Pilot = 150 metered + 11 from Avista - 2008
• Energy Trust of Oregon = 15 metered/94 total
• Idaho Power = 9 metered
• Puget Sound Energy = 41 metered
Idaho Power RTU
• 3 sites, 3 units per site, 12 months all units (Sept. 09 – Sept. 10)
• Level 1 monitoring 2 per siteLevel 2 monitoring 1 per site
• Heating signal at 1 unit per site• Heavy equipment supply/repair; title
insurance company; wholesale beverage
Idaho Power RTU Summary Results
Summary weather compressor Savings Pre Post Pre
site ID RTU ID size tons data Stages kWh/yr kWh/yr kWh/yr
t'stat stages Econo?
Bigelow #1 5 BOISE 1 -2,145 8,193 10,339 Yes Bigelow #2 7 BOISE 2 0 6,236 6,236 Yes Bigelow #3 10 BOISE 2 6,479 38,710 32,231 Yes Cesco #1 7 BOISE 1 86 14,351 14,265 yes Cesco #2 7 BOISE 1 0 12,072 12,072 no Cesco #3 6 BOISE 1 -7,905 7,827 15,733 yes Nampa #1 5.5 BOISE 1 -180 7,162 7,342 yes Nampa #2 7 BOISE 1 -7,227 2,853 10,080 yes Nampa #3 5.5 BOISE 1 6,161 10,652 4,490 yes
Interpretation of Results - Idaho
• 2 units fan power increase due to filter cleaning
• 1 unit incomplete economizer damper opening
• 2 units fan schedule increase to 24 hours, major losses
• 1 unit fan schedule reduction, major savings
• 1 unit properly operating in pre-retrofit
• 2 units failure to set back schedule
Take Away Results - Idaho
• Net savings all RTUs: - 4,700 kWh/yr• Savings target for refined settings: 23,000 kWh
dependent on schedule settings
Favorable Schedule Change - Idaho
Time Series
0
2
4
6
8
10
12
2016
6
2064
6
2112
621
606
2208
6
2256
6
2304
6
2352
6
2400
6
2448
6
2496
6
2544
6
2592
6
2640
6
2688
6
2736
6
2784
6
2832
6
2880
6
2928
6
2976
6
3024
6
3072
6
3120
6
3168
6
3216
6
3264
6
3312
6
3360
6
3408
6
3456
6
3504
6
3552
6
3600
6
3648
6
3696
6
3744
6
3792
6
3840
6
3888
6
3936
6
3984
6
4032
6
4080
6
4128
6
Hour of Day
Pow
er k
W kW #3OSA/10max
A Puzzle - IdahoEnergy Signature
0
20
40
60
80
100
120
140
160
180
200
220
40 45 50 55 60 65 70 75 80 85 90 95 100
Mean Month Temperature
Ener
gy, k
Wh/
day
mod postmod predata predata post
This unit had a significant economizer improvement.
Why did slope increase?
Maximum Power Signatures - Idaho
• Fan power decreased from ~1.5 kW to 1.4 kW due to filter replacement because flow increased
• Post-retrofit power increased for both stages due to flow increase, more cooling delivered
• Increased cooling doesn’t reduce cooling energy because thermostat setting not achieved
Compressor Usage
0
2
4
6
8
10
12
14
40.0 45.0 50.0 55.0 60.0 65.0 70.0 75.0 80.0 85.0 90.0 95.0 100.0
Average Hourly Temperature, deg F
Com
pres
sor k
Wh
or M
ax k
W
pre comppost comppre maxpost max
Next Steps - Idaho
• Properly set schedules• Monitor winter operation –consider morning
warm up• Next summer establish improved post-retrofit
performance and savings
California RTU Monitoring
• About 300 RTU new replacements instrumented for post-retrofit air-side output and electrical input
• No pre-retrofit measurement – “empirical pre-retrofit baseline drawn from selected samples”
• Monitored for 1-2 summer months
• Differ from NW monitoring by inclusion of return RH and Supply Air Temp with hourly data structure not average daily structure
• Results are normalized to performance efficiency
• Reconciliation with DEER modeling
California Results Example 1Analytic Target: Monitored performance as EER vs. Temperature
EER Performance Model
0.002.004.006.008.00
10.0012.0014.0016.0018.0020.00
70.00 80.00 90.00 100.00 110.00
Hourly Temperature, deg F
EER
model
hi
mxt
lo
California Results Example 2Monitored performance Compared to DEER
EER Performance
0.00
2.00
4.006.00
8.00
10.00
12.00
14.0016.00
18.00
20.00
70.00 80.00 90.00
Hourly Temperature, Deg F
EER
observed SEER 10 ref SEER 13 ref
Summary Results - CA
• Results to be published 12/21/09• Observed performance generally lower than
modeled expectation
Regional Results Database• Results from all programs will be entered• Primary structure a directory tree with each
program results as a separate directory• Each directory: unit raw data/template +
results summary for each units + site/unit characteristics & service measures
• Uniform format not being designed• Summary data will include selected site/unit
characteristics
Database Summary View
Site Summary• Site ID• RTU ID• Weather data• Annual kWh pre• Annual kWh post• Compressor stages• Compressor max duty (frac of
full load)• Economizer (y/n)• Monitoring level
Pre- and Post- Service Summary• Fan kW• Fan duty (frac of full load)• Baseload kWh/day• Balance point temp• Slope kWh/day/degF• Demand @ 80 deg F, Stage
1&2 kW• Compressor trigger degF
Database Format Refinements
• The format will change to accommodate the economizer analysis made possible by the Y1 signal most recently being monitored
• The format will change to accommodate more detailed descriptions of measures applied
• The summary row proceeds from the current template. Other analysis approaches and revised templates may have different summary row formats
Use of Regional RTU Data
• Data to be available through NPCC site• Getting 8760 results/analysis/EER vs Temp• EUI per conditioned sf• Sensitivity analysis on methodology• IPMVP Method B analysis: 2 week data only• Correlating data to building characteristics -
partial data available• Annual savings methodology using signatures
RTUG Next Steps
• Prepare presentation to RTF• Discuss with NPCC staff, RTU database implementation
+ integration with other regional buildings-related database(s)
• Further development of ‘Expected Value Savings’ [aka Deemed Savings]
• Continue communications with California organizations
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