being charged to the building. Since this is
a ‘burdened’ rate – meaning it includes not
only energy costs but also operation and
maintenance costs, debt retirement, profit,
etc. – this inflated the percentage of the
building’s total energy use associated with
these utilities, compared to other uses such
as lighting, fan energy, etc.
This created often insurmountable
hurdles for building projects tying into
district energy, as discussed in detail in last
month’s column. In an attempt to address
this issue, the new guideline includes
formulas designed to convert the fully
burdened rate into an actual rate, reducing
the percentage associated with this utility.
Confused? I’ll explain in a future
column; however, trust me: It is good
news for district energy.
The addition of these formulas
addresses another primary concern for
district energy owners – the confidentiality
of their financial data. Now realistic
energy rates can be used in models
without district energy owners having to
reveal all of this information.
Absorption Chillers
Version 2.0 also includes provisions
for modeling absorption chillers in district
energy applications in both the baseline
and proposed building. Default efficiencies
for absorption cooling are also included
for use when actual data are not available.
Renewable Energy
The USGBC has always intended to
encourage the use of what it considers
to be renewable energy in district
energy plants, although its definition of
“renewable” is fairly narrowly defined.
However, the original guideline’s formula
for determining applicable credit contained
an error that basically made it impossible
to achieve any credit. Through much
discussion, the IDEA team was able to
bring the error to light, and it has now
been fixed in the new guideline.
Commissioning
The first guideline’s requirements for
commissioning have been further clarified
in the latest version, with provisions
added to address plant expansions. In
addition, the requirements have been
modified slightly to align better with LEED
for Existing Buildings requirements. (A
detailed discussion of this topic is available
in my Fourth Quarter 2009 column
“Answering the Call.”)
Combined Heat and Power
I saved this issue for last because the
USGBC did too. In fact, if it were not for
combined heat and power, version 2.0
would have been released several months
earlier. However, one of our committee
members, Armand Agasian with Con Ed,
discovered a critical flaw in the proposed
formulas that would have wreaked havoc
for designers and reviewers. Unfortunately,
the flaw was so subtle that it took a while
to communicate, resolve and get buy-in
from all the work group members. Labor
pains! Once we did, though, version 2.0
went to press. Thanks, Armand, for helping
prevent a premature delivery.
Version 1.0 did not address CHP but
relied on a separate and often confusing
CHP-specific guideline that was not
focused on district energy. Similar to
the treatment given TES in the original
document, this separate CHP guideline
really focused on accounting for CHP
within a building itself and not in a district
energy application. Just as it did on the
topic of TES, IDEA provided data to the
work group on CHP, which aided the
group’s understanding of the positive
environmental impacts associated with
CHP in district applications. As a result,
CHP guidelines specific to district energy
have been added to version 2.0.
CHP guidelines specific to district
energy have been added to
version 2.0.
These CHP-related guidelines include
default efficiency numbers, similar to
previously included chilled-water, steam
and distribution defaults, allowing
designers to model CHP when data are
not available. As with other defaults,
however, the numbers are purposely set
at unattractive levels, i.e., 22 percent
electric generation efficiency and 25
percent thermal generation efficiency.
The intent is to encourage CHP owners
to determine their actual system energy
efficiency instead of using defaults.
Are We There Yet?
While we have certainly come a long
way with the new guideline, our work has
really just begun. Because of the length
and complexity of version 2.0, IDEA has an
opportunity to help designers, owners and
even LEED reviewers better understand its
proper application. As such, the association
is working diligently on a version 2.0
applications guide. The USGBC has agreed
to review the guide when completed,
and it may cosponsor its release. This
gives IDEA members the opportunity to
lead the marketplace as the experts on
version 2.0. Current plans are to release
the applications guide prior to IDEA’s 24th
Annual Campus Energy Conference in
February 2011.
We also need to work together to
create some marketing literature, which
can be used by those responsible for selling
district energy utilities, to explain the
benefits of our systems to building owners
and designers that are pursuing LEED
certification.
The most critical goal is to build on
the foundation we have laid with the
USGBC. Over the past 18 months, in the
USGBC’s eyes, IDEA has moved from being
a minor player in an obscure industry to
the representative of the district energy
industry. From this position, we can continue to influence the development of future
versions of the guideline so that it accurately captures the environmental benefits
district energy can bring to the table.
Let us be diligent in doing so!
Tim;Griffin,;PE,;LEED,
AP, is IDEA’s liaison with
the U.S. Green Building
Council and serves on
IDEA’s board of directors.
He is a principal and
branch manager with
RMF Engineering Inc., a firm specializing in
district energy system planning, design and
commissioning. A registered engineer and a
LEED Accredited Professional, Griffin has a
bachelor of science degree in mechanical
engineering from North Carolina State
University and a master of business
administration degree from Colorado
State University. He may be reached at
tgriffin@rmf.com.
