ASHRAE Journal - February 2023 - 60

TECHNICAL FEATURE
FIGURE 3 Linear and Change-point Linear Models Used in Guideline 14.
B0
B0
Ambient Temperature
(a)
B1
B0
Ambient Temperature
(c)
B2
B0
Ambient Temperature
(b)
B1
B1
B2
Ambient Temperature
(d)
B1
B0
B3
Ambient Temperature
(e)
Ambient Temperature
(f)
B1
B0
B3
Ambient Temperature
(g)
four or fi ve-parameter change-point
linear models, variable-based degree
day models, and multivariate linear
and change-point linear models as
indicated in Table 2 (https://tinyurl.
com/JournalExtras), and as shown
in Figure 3. These models represent
the most widely used models for
calculating baseline energy use
in commercial and institutional
60
B4
B2
This fi gure shows several of the
models used in Guideline 14-2023,
including: a) mean or constant model;
b) two parameter linear models;
three parameter change-point linear
models for c) heating and d) cooling;
four parameter change-point linear
models for e) heating and f) cooling;
and g) a fi ve parameter change-point
linear model.
buildings.4,7 - 16,17 Software for calculating
the models included in
Table 2 has been developed for public
distribution by ASHRAE under
Research Project 1050 RP.18,19 These
models are available for download
by ASHRAE members.
Whole-Building Calibrated Simulation Approach
The whole-building calibrated
ASHRAE JOURNAL ashrae.o rg F E B R U A RY 2 0 2 3
B2
B0
B1
B3
B2
simulation approach involves the
use of a commercially available
hourly, whole-building computer
simulation program to create a
building energy model of energy
use and demand of the facility.
Originally, this was to be limited to
public domain, hourly (i.e., 8,760
hours per year), whole-building
computer simulation programs.
However, with the completion of
ASHRAE Standard 140, this defi nition
was expanded to include any
commercially available computer
simulation program that could be
shown to be in compliance with
ASHRAE Standard 140, Method of
Test for Evaluating Building Performance
Simulation Software. ASHRAE also has
several additional research projects
that are intended to strengthen
future versions of ASHRAE
Standard 140, including Research
Project 865-RP-Development of
Accuracy Tests for Mechanical
System Simulations.
The energy simulation model,
typically a whole-building model of
pre-retrofi t conditions, is calibrated,
or checked against, actual measured
energy use and demand data, measured
weather data and possibly
other operating data during the
pre-retrofi t period. The calibrated
model is then used to predict energy
use and demand of the post-retrofi t
conditions. Savings are derived
by comparison of modeled results
under the two sets of conditions or
by comparison of modeled against
actual metered results.
The whole-building calibrated
simulation approach is applicable
for the following conditions:
1. When accounting for multiple
energy end uses, especially where interactions
occur between measures.
Energy Usage
Energy Usage
Energy Usage
Energy Usage
Energy Usage
Energy Usage
Energy Usage
https://tinyurl.com/journalextras https://tinyurl.com/journalextras http://ashrae.org
ASHRAE Journal - February 2023

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