Page 24 - PDZA Sustainable Aquarium Brochure

HEATING: A CARBON (AND ACIDIFICATION) STORY

The Pacific Northwest is a mild climate. However, For this project, we elected to take advantage
it is still heating dominated with 433 annual of the great work Tacoma Power has been doing
Cooling Degree Days compared to 4,272 annual to minimize the carbon footprint of its fuel mix.
Heating Degree Days. In a heating dominated Natural gas has emission rates that are normally
climate, using high efficiency heat sources are about 14 times higher than that of utilities with
a major contributor to energy conservation the majority of their electricity coming from hydro
strategies. In the last 10 to 15 years, many power. Tacoma Power has about 90% of its power
mechanical engineers have relied on condensing coming from hydro sources. This makes electricity
boilers with efficiencies as high as 97% under full provided by Tacoma Power a much cleaner source
load condition. This means 97% of the energy of energy than burning natural gas for heat from
from natural gas combustion will be delivered to a CO2e perspective. It is important to point out
the heating hot water loop. While that sounds a baseline building (i.e. traditional approach)
amazing, there is one key issue as we relate this could have significantly increased the aquarium’s
back to our goal of reducing GHG emissions. total CO2e emissions and essentially erased all
Despite this very high combustion efficiency, of PDZA’s work to reduce CO2e emissions had
condensing boilers still burn a fossil fuel to create we not implemented the energy reduction and
heat and release carbon into the atmosphere. HVAC system strategies described in this paper
as illustrated in Figure 9. Here, you can see that,
Heat pump technology is a game changer for the with the proposed building energy conservation
building industry because it is far more efficient and fuel source strategies implemented, we
than fossil fuel combustion and uses electricity as significantly reduce the amount of CO2e
an energy source rather than directly combusting produced by the aquarium.
fossil fuels. With electricity as the energy source,
we have the opportunity to produce our own
renewable energy on site, purchase “green”
energy from the grid, or rely on the grid itself
having a low carbon footprint.

Figure 9—Annual Carbon Footprint for the PDZA Campus plus the Baseline and Proposed Replacement
North Pacific Aquarium

24 AQUARIUM OF THE SUSTAINABLE FUTURE: PUBLIC FACILITIES DESIGNED TO EMBODY CONSERVATION