166 Energy Project Financing: Resources and Strategies for Success
to simply measuring vibration amplitude, the machine vibration can be
displayed in time or frequency domains. The graphs of vibration in the
frequency domain will normally exhibit spikes at certain frequencies.
These spikes can be interpreted by a trained individual to determine
the relative health of the machine monitored.
The more sophisticated machines are capable of trend analysis so
that facility equipment can be monitored on a schedule and changes
in vibration (amplitudes and frequencies) can be noted. Such trending
can be used to schedule maintenance based on observations of change.
This type of equipment starts at about $3,000 and goes up depending
on features desired.
Preparing for the Audit Visit
Some preliminary work must be done before the auditor makes the
actual energy audit visit to a facility. Data should be collected on the
facility’s use of energy through examination of utility bills, and some
preliminary information should be compiled on the physical descrip-
tion and operation of the facility. These data should then be analyzed
so that the auditor can do the most complete job of identifying energy
conservation opportunities during the actual site visit to the facility.
Energy Use Data
The energy auditor should start by collecting data on energy
use, power demand and cost for at least the previous twelve months.
Twenty-four months of data might be necessary to adequately under-
stand some types of billing methods. Bills for gas, oil, coal, electricity,
etc. should be compiled and examined to determine both the amount of
energy used and the cost of that energy. These data should then be put
into tabular and graphic form to see what kind of patterns or problems
appear from the tables or graphs. Any anomaly in the pattern of energy
use raises the possibility for some significant energy or cost savings
by identifying and controlling that anomalous behavior. Sometimes an
anomaly on the graph or in the table reflects an error in billing, but
generally the deviation shows that some activity is going on that has
not been noticed or completely understood by the customer.
Rate Structures
To fully understand the cost of energy, the auditor must determine
the rate structure under which that energy use is billed. Energy rate struc-