ASHRAE Journal - August 2022 - 45

COLUMN ENGINEER'S NOTEBOOK
FIGURE 1 Energy master plan EUI heat map. (Source: Long Beach City College
Integrated Energy Master Plan)
FIGURE 2 Advanced Energy Retrofit Guide project planning flow chart. (Source:
Department of Energy/Pacific Northwest National Laboratory)
the process for prioritizing energy conservation measures
associated with an energy audit. Benchmarked
buildings should be compared to a peer sample using
ASHRAE/IES Standard 100-2018, Energy Effi ciency in
Existing Buildings, Department of Energy Commercial
Building Energy Consumption Survey (CBECS) and
other resources to determine how they compare to
similar building types.
Metered data should consist of a minimum of 12 consecutive
months, but having data going back several years
or more provides deeper insight into trends. A challenge
during the last two years is fi nding reliable data, as a
majority of campus buildings were partially and/or minimally
occupied due to the pandemic. Upon completion
of benchmarking the campus, a heat map of the campus
can be developed to identify the EUI of the buildings.
Figure 1 shows an example EUI heat map from a recent
integrated energy master plan at a community college.
Once the campus buildings are benchmarked, the next
step is to prioritize buildings and focus on energy reductions
on campus. It is important to coordinate with the
facility master plan to understand which buildings are
planned for removal in the near term so these buildings
are moved to the lowest priority. The energy reductions
could be broken down into three categories: existing
building commissioning (EBCx), energy conservation
measures (ECMs) and deep retrofi ts.
EBCx is the fi rst step in reducing energy use as it
has the lowest capital costs and the quickest payback.
ASHRAE Guideline 0.2-2015 and Guideline 1.2-2019
provide guidance on the commissioning process for
existing buildings and systems. This process will help
evaluate and correct known operational issues and may
lead to deeper capital improvements. For example,
EBCx can consist of recalibrating sensors, minor repair
of components (e.g., economizer dampers), re-enabling
temperature and pressure resets, etc.
Moving beyond EBCx and into a retrofi t, ECMs can be
considered as an energy effi ciency retrofi t for low-hanging
fruit with minimal capital investment. In contrast,
deep energy retrofi ts require a larger capital investment
and may have longer payback periods. The team should
develop a decision fl owchart to aid in the decision-making.
Figure 2 provides an example from the Department
of Energy's Advanced Energy Retrofi t Guide.
A list of ECMs should be developed based on a review
of as-builts, discussions with facilities staff, site walks,
etc. Preliminary calculations will determine initial estimated
paybacks. A higher education owner is typically
looking for a payback of seven years or less, but some
owners will require a quicker payback or be willing to
settle for a longer payback. It's important to understand
the payback threshold prior to recommending any ECM.
A calculation should be provided for each measure, and
these may also be grouped if desired. Depending on the
level of detail desired by the project team, calculations
can be a simple life-cycle cost analysis or a fully developed
energy model of the current system with the ability
to test ECMs. If a model is used, the software should
meet or exceed the requirements of ASHRAE Standard
140-2020, Standard Method of Test for the Evaluation of
Building Energy Analysis Computer Programs .
Retrofi ts can be categorized into those having a minimal
impact to implement on the building operations to
those requiring a deep retrofi t of equipment, infrastructure
and possibly space modifi cations.
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