EMIS ReportDesign-Prelim 2020sep11 - Flipbook - Page 23
Common
Metrics and
Analyses
Energy use
intensity (EUI),
kBtu/sq ft
Used to Identify
Example
High energy use relative to
the portfolio
Source: Aurora Public Schools
Heat maps
Scheduling improvements
Baseline reduction
opportunities
12am
3am
6am
9am
12pm
3pm
6pm
9pm
12am
Source: Macalester College
Scheduling improvements
Baseline reduction
opportunities
Peak demand reduction
opportunities
Energy use by hour
relative to modeled
prediction
Maximum
Average
Minimum
80
Kilowatts
Load profiles
70
3. SMART ENERGY ANALYTICS CAMPAIGN RESULTS
TABLE 2: Summary of commonly used metrics and analyses in EIS
60
50
40
12am
3am
6am
9am
12pm
3pm
6pm
9pm
12am
Source: Carleton College
TABLE 3: Summary of common faults detected by FDD technology
System Components Analyzed
Controllers (actuators/valves/
speed drives)
Dampers (air handling units,
terminal units)
Cooling/heating valves and coils
FDD Tool Analysis
Economizer operation/use
Simultaneous heating and cooling
Compare controller output setpoints to the actual condition to find failed devices.
Determine the stability of controllers.
Identify if a damper is stuck open, closed, at a fixed position, or leaking.
Compare mixed air temp to return air temp with the outdoor air damper closed.
Identify if a valve is stuck or leaking.
Identify a fouled or blocked coil.
Detect when temp difference exists across a coil when valve is shut or when the
system is not achieving a desired temp drop across a coil when valve is open.
Detect if the rooftop units (RTUs) or air handling units (AHUs) are not economizing
when they should.
Detect if the RTU/AHU is economizing when it should not (i.e., calculate the relevant
theoretical outdoor air ratio with outdoor air temp, return air temp, and mixed air temp).
Detect if the economizer lockout setpoint is too high or low.
Detect if unnecessary heating, economizer cooling, and/or mechanical cooling
occur at the same time.
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