The RTU Annual Usage Calculator (companion to RTU protocol SBW format) is Excel sheet for a single site 4-week monitoring (often automated using SAS for larger volume work).

•Takes data logger results for a 4 week monitoring period (about 40,000 rows of data)

•Aggregates to hourly and daily averages

•Produces diagnostic plots, and allows point editing

•Produces RTU signatures for two occupancies, default: weekday and weekend

•Produces NAC, savings estimate will require a separate output for pre-NAC and post-NAC

Calculator Inputs• RTU power by minute (could be from single calibrated CT)

• RTU outside air temperature by hour from minute data or from local weather station)

• RTU supply air temperature by minute (not necessary for annual usage estimate but useful for estimating minimum osa %)

• Annual Histogram for normal average daily temperature at site

Calculator Outputs• Operating history graphs

•Measurement of fan power and duty cycle from minute data

• kW vs. temperature mode map

•Signatures for weekday and weekend operation

• Normalized annual energy use estimate

Operating History

Operating History - second two weeks

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Hour Row Number

KW

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OSA/10Max kW

Operating History w/Minimum Hourly Supply Temperature

Operating History- first two weeks

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Mode Map kW vs. Hourly Temp

Temperature vs kW - full four weeks

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Hourly Temperature, deg F

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Max kW

Signature Graph

Signatures Inspection Plot

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Mean day Temperature, deg F

En

erg

y, k

Wh

/da

y

week day

model

week end

model

Normalized Annual OutputCalculation of Normalized Annual Consumption

Site Temperature signature information from data tabHistogram week end week day

baseload 23.56719 22.71532balance t 54.81856 46.68124slope 1.359394 1.364004

weekly annualBin Frequency weekend weekday melded bin kWh

10 015 0 12.5 23.56719 22.71532 22.95871 020 0 17.5 23.56719 22.71532 22.95871 025 2 22.5 23.56719 22.71532 22.95871 45.9174230 4 27.5 23.56719 22.71532 22.95871 91.8348435 5 32.5 23.56719 22.71532 22.95871 114.793640 26 37.5 23.56719 22.71532 22.95871 596.926545 53 42.5 23.56719 22.71532 22.95871 1216.81250 73 47.5 23.56719 23.83212 23.75642 1734.21955 42 52.5 23.56719 30.65214 28.62787 1202.3760 45 57.5 27.21233 37.47216 34.54078 1554.33565 59 62.5 34.0093 44.29218 41.35421 2439.89870 36 67.5 40.80627 51.1122 48.16765 1734.03575 17 72.5 47.60324 57.93222 54.98108 934.678480 3 77.5 54.40021 64.75224 61.79451 185.383585 0 82.5 61.19718 71.57226 68.60795 090 0 87.5 67.99415 78.39228 75.42138 095 0 92.5 74.79112 85.2123 82.23482 0

100 0

More 0 Normalized Annual Consumption, NAC >> 11,851 kWh/yr