Data Collection & Analysis Flashcards

Which statistical measure is most useful for identifying outliers in energy consumption data?

Answer: Interquartile range (IQR)

The IQR defines the middle 50% of data, and values beyond 1.5×IQR from the quartiles are flagged as outliers.

A utility meter records energy use every 15 minutes. What is this interval called?

Answer: Interval data

Sub-hourly meter readings captured at fixed time steps are called interval data and are used for detailed load profiling.

An energy manager wants to compare the energy efficiency of buildings of different sizes. Which metric is most appropriate?

Answer: Energy Use Intensity (EUI)

EUI normalizes energy consumption by floor area (kBtu/sq ft/year), enabling fair comparison across buildings of different sizes.

What does a low R² value in a regression model for energy consumption indicate?

Answer: The independent variables explain little variance in energy use

A low R² means the chosen independent variables (e.g., weather, occupancy) do not adequately explain the variation in energy consumption.

Which data source provides outdoor temperature data most commonly used in energy regression analysis?

Answer: Heating degree days (HDD) and cooling degree days (CDD)

HDD and CDD are derived from weather station data and are the standard independent variables for correlating energy use to outdoor temperature.

What is the primary purpose of a data historian in an industrial energy management system?

Answer: To store and retrieve time-series process and energy data

A data historian archives time-series data from sensors and control systems, enabling trend analysis and performance benchmarking.

When normalizing energy data for weather, which base temperature is most commonly used for calculating heating degree days in the US?

Answer: 65°F

65°F (18.3°C) is the standard US base temperature for calculating HDD, representing the point below which heating is typically required.