Billing Simulation Tool for Commercial Buildings

Abstract

A spreadsheet tool has been developed that allows quick adjust-
ment of a simplified engineering model to match actual utility bills.
The tool utilizes billing analysis of commercial facilities to: (1) diag-
nose energy patterns and end-use consumption; (2) calibrate savings
estimates to agree with actual usage; (3) verify vendor claims for en-
ergy products and services, (4) generate performance targets and com-
pare against actual energy bills. This application represents a low-
cost, simplified commissioning check or verification for performance-
based contracts.
The tool is designed to operate with only simple information
about the facility and to focus on the HVAC system. It represents one
quick approach to treating the facility as an integrated whole. Case
examples illustrate how the tool is useful in diagnosing energy prob-
lems, guiding on-site audits, establishing predicted targets for O&M
tracking and performance verification.
Overall precision of the results was quite good. In one study,
savings estimates were provided with a SE value less than 5% of an-
nual consumption. This value defines the level of resolution that can
be expected from monthly whole-building analysis. The project dem-
onstrates that sufficiently precise simulations can be developed from
whole-facility billing data at a greatly reduced cost compared to tradi-
tional engineering models.