District Energy | Spring/Summer 2019 31 © 2019 International District Energy Association. ALL RIGHTS RESERVED.
discussion. Does the system rely on reactive management, i.e., through activating
alarms followed by sending an employee
to fix the issue? Or does the system offer
proactive, predictive asset management
The importance of maintaining a
balance between reliability and availability (uptime) can be demonstrated by
the asset condition curve in figure 1.
(Reliability is illustrated by the y-axis
and availability by the x-axis.) Plant owners should focus on the potential-to-functional failure (P-F) interval where
the relationship between reliability and
availability is symbiotic. Within that
interval are tangential measurement
systems providing vibration, noise, ther-mographic and other asset health data.
Depending on the application, various
measurements can be made using these
systems that will support predictive or
preventive maintenance. Figure 1 illustrates a few of many technologies that
can be used to positively affect the ability to keep the asset functional.
There will be additional human and
capital costs to install the necessary equip-
ment to support the target of 99.9 percent
uptime. Management must be willing to
commit these resources to pay for vibra-
tion systems, thermal measurement sys-
tems and so forth in the P-F interval. These
tangential systems have equipment costs,
installation costs, training costs and inte-
gration costs. Without investment in these
tools, the demand for the uptime can’t be
met in many cases because there is no real
way to get a view of the health of the asset
versus the runtime that will inevitably lead
to failure. Owners need to optimize that
portion of the P-F curve.
Like-for-like: May be the only viable path
If the team put in charge of the
upgrade initiative believes the resources
and the deadline milestones will not be
put in place to support all elements of a
new asset management system, then the
plant should probably consider falling
back to a simple like-for-like upgrade of
its control system.
USING ASSET MANAGEMENT TOOLS ON
THE DIGITAL BACKBONE OF THE CONTROL
SYSTEM WILL PROVIDE REAL RETURNS ON
However, when the team has the
financial commitment to add human and
equipment resources to meet deadlines
for the addition of the tangential equip-
ment, new software and other costs, the
added functionality of a new control sys-
tem will provide significant value for the
facility. Using asset management tools on
the digital backbone of the control sys-
tem will provide real returns on invest-
ment, as is illustrated next at the Univer-
sity of Rochester Medical Center.
MANAGING AND QUALIFYING THE NEW
Installing new controls does provide value, as shown in the first upgrade
scenario, as long as plant owners have
a vision for the change. The question
they must answer is whether the value
that a new control system provides is
great enough to justify the investment.
With a new system, plant owners need
to make sure they can quantify how the
new changes are measuring up to their
expectations. This fourth scenario is not
really a justification to do either a like-for-like facelift or full modernization,
but it is important for the evaluation
team to consider in order to make the
Example: The University of Rochester
Medical Center, New York
At the University of Rochester Medical Center (URMC) in upstate New York,
FIGURE 1. Asset condition curve.
Source: Mark Grant, Schneider Electric.
Point at the onset of malfunctions
Failure point beyond functional operations
Repair or run to failure
P-I interval P-F interval