Review:STANDARD PROTOCOL FOR MEASUREMENT OF FAN AND COOLING SAVINGS FROM COMMERCIAL-
SECTOR PACKAGED ROOFTOP HVAC UNITS
Regional Technical Forum
February 14, 2012
RTU Savings/MWa – NPCC 6th Power Plan
RTUs in 6th Power Plan…
AIR-AIR HT P
UMP
BOILER O
NLY
BOILER / G
EOTH
ERMAL C
OOLING
BOILER/C
HILLER
BOILER/D
X COOL
BOILER/U
NIT AC
COMBO HT/AC UNIT
DUCT HT/C
HILLER
DUCT HT/D
X COOL
DX COOL ONLY
GEOTH
ERMAL H
EAT /
CHILLER
ONLY
GEOTH
ERMAL H
EAT /
DXCOOL
GROUND SOURCE H
T PMP
H2O LOOP HT P
UMP
HT REC
/DX COOL
PKG HEAT O
NLY
PKG:HEAT/D
X COOL
PKG:HT/EVAP CL
UNIT HEA
T/AC
UNIT HT O
NLY0.00%
5.00%
10.00%
15.00%
20.00%
25.00%
30.00%
35.00%
40.00%
45.00%
Primary HVAC System Type - REGIONWT07 - n= 1.3 billion SF (nearly half the stock) - Only cases with some primary or secondary Package
HVAC equipment#1 TARGET
#2 Target
NW Commercial Building Stock Assessment(CBSA) RTU counts-6th Power Plan
AREABIN
Average of Count Package
RTU UnitsAverage of Pack
HVAC Tons
Faction of PNW Floor
AreaBuilding Count
Fraction with RTU RTU Count
1. <5,000 1.9 4.7 10% 89877 70%
118,000.00
2. 5,000-20,000 4.3 5.5 23% 57593 61%
151,000.00
3. 20,000-50,000 8.8 9.0 19% 15616 54%
74,000.00
4. 50,000-100,000 16.1 27.5 15% 5816 35%
33,000.00 5. 100,000-500,000 19.7 14.1 28% 4946 30%
30,000.00
6. >500,000 5.5 5.2 4% 175 5%
100.00
Grand Total 8.9 7.0 100% 174023
406,100.0
0
52% floor area <50kSfPopulation
64% of buildings <6 tons79% of buildings <10 tons
PNW RTUs an aging fleet…
Age category Under 5 tons 5 to 10 tons Over 10 tons44% 36% 20%
0 to 4 17% 30,000 24,000 14,000
5 to10 32% 56,000 46,000 26,000
10 to 19 35% 62,000 50,000 28,000
20+ years 16% 28,000 23,000 13,000
51% = 204,000 of the units have been on the roof for over a decade!
RTU Protocol Issues Raised
Measure exclusions: which measure are excluded even though not tested?
Pre and Post upgrade scheduling: can we do Pre in August and Post in May?
Multiple annual site review to better understand confidence interval
Cost to implement the protocol needs closer review: cost estimate based on mature program and lessons learned
Calculator is for a single unit; sampling protocol is for program evaluation purposes, not unit savings calculations
All protocols and calculators will need ongoing RTF support (2013 work plan/budget)
RTU Protocol Confidence LimitsLimited Sites
• Confidence limits are normalized relative to annual energy• Confidence limits highest for metering periods starting in late June to
mid-July• Confidence limits of +- 5% are achieved with metering periods starting
in late May and early August
Assessment of 90% Confidence Intervals (West)
Assessment of 90% Confidence Intervals (East)
Nominal 90% Confidence Intervals (East)(Actual coverage rate around 50%)
-40%
-30%
-20%
-10%
0%
10%
20%
30%
40%
RTU0300 RTU0304 RTU0305 RTU0306 RTU0353 RTU1004 RTU1005 RTU1006 RTU1017
Nominal 90% Confidence Intervals (West)(Actual coverage rate around 50%)
-40%
-30%
-20%
-10%
0%
10%
20%
30%
40%Nominal 90% Confidence Intervals (West)
RTU0032
RTU0034
RTU0036
RTU1001
RTU M&V Field Protocol
• Purpose• Definition of Key Terms• Required Knowledge and Skills of Practitioner• Required Data Logger Commissioning
o One Time Site Measurements and Descriptionso Data Logger Measurementso TMY3 Weather Data
• Savings Estimation Steps• Estimate of Typical Measurement Cost• Relationship to Other Protocols and Guidelines• Sampling Procedure for Program Evaluation
Purpose
Establishes a method by which annual electrical cooling and fan energy use and savings (kWh) can be estimated for a commercial packaged rooftop unit (RTU) optimized for performance including in-field data collection requirements/methods, annualized use/savings calculation method
Definition of Key Terms
Baseline
Pre
Post
Commissioning:
– data logger/storage/comm equipment
– RTU post-upgrade
Upgrade Measures
Required Knowledge and Skills of Practitioner
Appropriate electrical and related safety procedures
Knowing the protocol and calculator Equipment inspection: control points,
schedules, cooling stages Logging equipment selection and use Measurement equipment commissioning Ability to interpret results
Required Data Logger Commissioning
Communications & data storage True power sampling with current
transducers @ 3-minute interval If site temperature measurement is used,
verify temperatures with 2nd instrument If supply air temperature is used, place away
from supply air plenum walls Full data set should be tested immediately Onboard data storage up to 70 days @ 3-min
interval
Key Measurement Considerations
Outdoor air temperature on site or nearby NOAA weather station
Supply air temperature optional: for diagnostics, not calculator
Timing of measurement: 4 wks pre/4 wks post
pre: 3rd wk May-June; post: 1st wk August-Sept
Timing of retrofit: July
Savings Estimation
Automated calculator with true power/temperature data only
Sequence of Calculations:
Compute the Normalized Annual Consumption (NAC) for pre/post data
Energy Savings Calculation Sequence
Electric Load Shape Calculation Sequence
Demand Savings Calculation Sequence
Estimate of Costs
Mature case with lessons learned
Expedited approach using NOAA weather for 2 RTUs in same panel = $1250 or $635/RTU
Comprehensive approach site weather, 3 RTUs single roof = $2,450 or $817/RTU
Annualized Energy Use / SavingsCalculator
Next Steps
February 16, 9am-12pm RTUG follow up meeting to Feb 14 RTF review
RTF members invited to participate
Planning to make final protocol recommendation at March RTF meeting