Appendix B 325
data come from utility bills or other special whole building meters. If
such special whole building sub-meters were in place anyway there
may be no extra cost, providing they are properly read, recorded and
maintained. The primary cost elements in Option C are i) utility bill or
data management and running of the model with each month’s utility
data, and ii) tracking and adjusting for conditions which change after
the baseyear.
Option C is best applied where:
- the energy performance of the whole facility is to be assessed, not
just the ECMs. - there are many different types of ECMs in one building.
- the ECMs involve diffuse activities which cannot easily be isolated
for the rest of the facility, such as operator training or wall and
window upgrades. - the savings are large enough to be separated from noise in the
baseyear data during the time of monitoring. - interactive effects between ECMs or with other facility equipment
is substantial making isolation techniques of Options A and B
excessively complex. - Major future changes to the facility are not expected during the
period of savings determination. A system of tracking key operat-
ing conditions can be established to facilitate possible future non-
routine Baseline Adjustments. - reasonable correlations can be found between energy use and other
independent variables
3.4.4 Option D: Calibrated Simulation
Option D involves the use of computer simulation software to
predict facility energy use for one or both of the energy use terms in
Equation 1. Such simulation model must be “calibrated” so that it pre-
dicts an energy use and demand pattern that reasonably matches actual
utility consumption and demand data from either the baseyear or a
post-retrofit year.