ASHRAE Journal - September 2014 - 40

natural gas, respectively. The coefficient of determination (R2) between
measured and modeled energy use
improved noticeably from uncalibrated models (0.86) to calibrated
models (0.98) as seen in Figure 3.
Figure 3 shows measured and modeled electricity and natural gas consumption both plotted in the same
units of energy. The models' monthly
predictions are plotted one for one
against the monthly measured values.
If the model were predicting the measured consumption perfectly, then the
points would each lie on a straight line
with a slope of one. However, for any
given month and model, the predicted
value varies from the measured value
by some over-prediction or underprediction. For the uncalibrated
data, it is apparent that many of the
monthly predictions deviate far from
the measured energy usage. Through
our calibration effort, we were able
to improve the models' agreement,
thereby moving each point closer to
the line of perfect agreement.

Energy Projections
We then inserted the future climate data into the calibrated energy
models to estimate the energy
impacts for each climate scenario.
Total site energy consumption
increased over current climate conditions for each climate scenario
we examined. The total projected
annual energy cost is expected
to increase 8.6% and 17.7% for the
low and high impact scenarios,
respectively.
Our models showed an increase of
between 4.3% and 11.3% in annual
electricity consumption for the low
and high impact future scenarios,
respectively. Interestingly, they project that peak cooling demand will
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SEPTEM BER 2014

decrease 4.7% under the low impact
scenario, due to lower projected summer humidity levels (even though
peak dry-bulb temperatures are
expected to increase). The low impact
peak electric demand decreases 2.4%,
following the reduction in peak cooling. Conversely, the high impact scenario projects a cooling peak demand
increase of 36.8% and an electrical
peak demand increase of 19.4%. This
reflects the significantly higher drybulb and wet-bulb temperatures projected under this scenario.
Total gas consumption increased
23.8% and 36.0% for the low and
high impact scenario respectively,
with a corresponding increase in
peak heating demand of 37.9% and
43.1%. This follows the generally
lower and more variable wintertime
temperatures projected under both
climate scenarios. Figure 4 illustrates
the results.

Climate Change Adaptation
We identified the energy-efficiency
measures needed to offset climate
change impacts. Table 3 outlines
each in more detail. The three primary strategies include improving roof insulation, upgrading the
water-cooled chillers and installing
ventilation energy recovery wheels.
Additional roof insulation indirectly
reduces the cooling and heating loads
at SSC during the more extreme summers and winters by reducing the
amount of energy used by the heating
and cooling equipment. Upgrading to
more efficient chillers directly reduces
the amount of electricity needed to
offset the increased need for cooling
during hotter summers. The energy
recovery ventilation will recover
energy from the exhaust air stream,
reducing the wasted energy already

ASHRAE Journal - September 2014

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