ASHRAE Journal - July 2023 - 20

FEATURE
and we're getting better at that. However, the thesis goes
something like this: we have this concept of zero energy
buildings; therefore, all the carbon is in the materials
and refrigerant emissions. That's true, but the first part
of that thesis has failed because we are not building all
buildings to be zero energy. We can work on embodied
carbon, but we need to continue to push towards reducing
buildings loads. Remember that energy consumption
in buildings is still approximately 40%
of the US energy pie (with industry and
transportation making up 27% and
33%, respectively, of energy consumption)-and
that number isn't much different
worldwide.
Therefore, efficiency is really, really
important-reduce the energy. Design heating
systems that minimize on-site fossil fuels.
Look at the embodied carbon for the materials put into
the building. All these pieces make up the whole building
carbon. One side note here-even if your building
is powered by renewable energy, saving energy means
that renewable energy can go somewhere else to
reduce fossil fuels.
What Interesting Projects Have You Seen That Have Piqued
Your Interest?
There are big movements out there now to collect
food waste and run them into bio digesters. There's one
in Southington, Connecticut, that collects food scraps
from parts of Connecticut and they digest these materials
with a digester system.7,8 Basically, they're trying to
pull that carbon out. Then they take the methane that's
coming out of it and run it into a generator. It's producing
carbon dioxide (CO2), but it's not releasing methane,
and they're getting electricity out of it.
Even things like heat pump systems, when they operate
on a larger scale, can tap into sewer and wastewater,
which tends to be warm (as is the case, for example, for
hot water used in showering), and extract the heat to
heat buildings. There's a big demonstration of this in
Denver, Colorado, where energy is being taken out of
the Denver Metro wastewater and being put into a set of
buildings with a big heat pump, which then cools down
the water.9,10 Environmentally, the water is being discharged
into the river at closer to what its natural temperature
should be. We're recapturing that waste energy
to heat that complex.
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ASHRAE JOURNAL ashrae.o rg
J U LY 2023
What Are Some Challenges Engineers May Face While
Implementing Applications of Decarbonization Technology?
One challenge is money, money, money. Another is
the electrical capacity to implement decarb applications,
and I would challenge engineers to really study
the whole problem and not just a piece of it. Especially
for new construction, look into investing more money
in the envelope in order to save money on the HVAC
and the electrical. I am finding that more and more
owners are asking for total cost of ownership
as a tool and seeing reducing carbon as an
investment and risk mitigation strategy.
For existing buildings, look at the original
design intent and ask if those loads
are still there. A lot of buildings were
designed around big lighting loads, and
over the years we've reduced those. How
do you get that electrical capacity back and
use it for a different purpose? How do you use the electrical
capacity that you currently have for air conditioning
and to also provide heating? When you go into
a building, you can't just say, 'We're going to leave the
cooling system alone. We need to deal with the heating
system.' That is sometimes where we see the problem-
in the equipment that is burning fossil fuels-but the
solution is much broader. We need to think about how
we take the cooling system and make it produce heat
for the building using the same electrical capacity.
There's definitely engineering firms out there that
have really thought through optimizing everything-the
envelope, the lighting, the building-to come up with
something that is cost neutral or near cost neutral.
The energy side gets a bad rap for creating cost
increases, but there's lots of decisions that are made
that do other things. There are beautiful buildings out
there that have architecture integrated with the energy
aspects of it. That's one way to think about this-making
beautiful buildings that are very functional and meet
the needs of the owner, including meeting decarbonization
goals.
In the 1800s, you look at these pictures of cities, and
they all have smokestacks. Smokestacks were a sign of
progress and prosperity. Well, people spent money to
build ornate smokestacks. And yet we've kind of shifted
in that is no longer the sign of prosperity. Today's sign of
prosperity might be no smokestacks. You know, it's a different
way of thinking about what success looks like.
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ASHRAE Journal - July 2023

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