Is fear holding us back?
Hemant R. Mehta, PE, President and Chief Executive Officer, WM Group Engineers PC
District cooling system optimi- zation has always made good economic sense. After all, producing a cooling Btu can cost up to 2. 5
times as much as a heating Btu, making
it especially important to optimize cooling systems. Today, it may be one of the
most cost-effective investments that a
plant manager can make. Technologies
certainly have improved over the years:
Chillers are more efficient, and control
systems are now finely tuned – both of
which make optimization more achievable. But what if a plant manager discovers that the potential operating efficiency
of the system is limited by its original
design? Can it still be optimized?
Yes, a district cooling system can still
be optimized, but it’s worth a step back
to understand the reasoning behind that
original design. The engineers who created it undoubtedly aimed to do the right
thing to meet client expectations. Nobody
intentionally designs an inefficient system. However, in the quest to guarantee
system reliability and complete a project
on time and on budget – two laudable
goals – fear of failure can result in a less-than-optimal design.
The first fear is that the system won’t
work under every possible operating
scenario. So there may be a tendency to
overdesign district cooling systems to protect system owners and operators. While
Courtesy WM Group Engineers PC.
These images from a chilled-water plant at a major university show the plant before and after numerous
pumps were removed.
good in concept, it can result in significant
energy inefficiencies and higher costs.
The second fear is that the project
won’t be profitable enough or will not be
completed on time, and the consulting
firm won’t meet its productivity goals.
When a project budget is tight, it is tempting to look at similar past projects and
‘copy and paste’ solutions onto new
systems. There is nothing wrong with
utilizing solutions that have proven to
be successful, but to achieve maximum
efficiency, the intricacies and special features of each new system must also be
addressed – especially if a new plant needs
to be integrated with an existing system.
The good news, though, is that good
detective work, effective system redesign
and comprehensive training can bring
about significant change in operational
efficiency. As shown in the case studies
presented here, pumping system design is
quite often the major inefficiency culprit.
By addressing this issue and adopting
new operating practices, facility design-
ers and managers can move forward with
confidence and finally realize increased
energy and cost savings.
Pumping system design
is quite often the major
All Pumped Up
As everyone knows, pumps
installed in district cooling systems
consume energy. The greater the