QuEST Energy Modeling Spreadsheet - QuEMS

QuEST's Energy Modeling Spreadsheet ("QuEMS") provides change point regressions that characterize energy use in buildings with regard to a single independent variable, typically temperature. Energy use is not typically a linear function of temperature, but is a function that changes for different temperature ranges. The user picks the type of function that best describes a building or system's energy use, and QuEMS automatically determines the coefficients and the temperature ranges to which each portion of the function applies

QuEMS is designed to assist Measurement and Verification (M&V) analysis, including planning whether whole-building or system-level interval data will be sufficient to establish the savings with a reasonable amount of uncertainty. QuEMS can also be used to improve many other energy analyses.

Background

Energy efficiency practitioners commonly apply linear or polynomial regressions to obtain statistical models of energy use. However, these approaches are not always appropriate over the full range of ambient conditions, especially if applied to the energy use of a whole building. Energy is not typically a constant linear function of temperature, but is a function that changes for different temperature ranges. Change point regression models are commonly required. Please see ASHRAE Research Project 1050 for a description of change-point models (www.ashrae.org).

Appropriate energy models are recommended for documenting energy use patterns (e.g. "baseline" energy use) and quantifying energy savings by several guidelines, including ASHRAE Guideline 14-2002, "Measurement of Energy and Demand Savings," and the California Commissioning Collaborative's "Guidelines for Verifying Existing Building Commissioning Project Savings, Using Interval Data Energy Models: IPMVP Options B and C." To increase use of these types of models in the energy efficiency industry, and to help practitioners provide statements of model and savings uncertainty, and other statistical information, QuEST developed this tool.

Features

QuEMS includes multiple model types and also includes important statistical information, including the correlation coefficient and overall uncertainty in the regression.

Based on ASHRAE Guideline 14 Requirements
Model Types include:

linear regression models
3-parameter cooling models
3-parameter heating models
4-parameter models

Statistical Information includes:

Confidence Level (input)
R²
CV-RMSE
Savings Uncertainty
Net Determination Bias
Average Y
Average X
Standard Deviation of the Residuals, and more

Easy to Learn:

Intuitive Interface
Familiar Microsoft Excel environment
Paste-and-click simplicity

Graphics:

Scatter Chart of Data and Regression Model
Time-Series Chart of Data and Model, aggregated to Daily totals or averages

Flexible:

Easy definition of baseline period
Regressions exclude data not included in user-defined filter
Regular Excel capabilities are retained
Provides completed regression equation for use in other calculations

Screenshots

System Requirements

Microsoft Windows 2000/XP/Vista
Microsoft Excel 2003 (not compatible with Office 2007)
1GB RAM or better

The Quest Energy Modeling Spreadsheet is available for purchase through the Quest Software site, powered by Kagi.com