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