ASHRAE Journal - February 2023 - 10

LETTERS
feedstock and can be used as a direct
replacement of natural gas in current
CHP equipment and systems.
The respondents note " as RNG is
distributed through the same leaky
pipe as natural gas, it will emit
methane to the environment, and
substantially reduce the 'low carbon'
reality of the fuel source. " The latest
Environmental Protection Agency
(EPA) Inventory of U.S. Greenhouse
Gas Emissions and Sinks shows that
annual emissions from the natural
gas distribution system declined 69%
from 1990 to 2019, as natural gas
utility companies added more than
788,000 miles of pipeline to serve
21 million more customers.
Distribution systems owned and
operated by local natural gas utilities
emit only 0.08% of produced natural
gas. The pipeline infrastructure
adds only a small fraction of GHG
emissions to the overall reductions
that can be achieved through RNG
use in CHP facilities.
While existing hydrogen sources
in the U.S. are indeed produced primarily
from natural gas, the respondents
ignore the massive ongoing
global effort to develop pathways
to clean hydrogen and the U.S.
Department of Energy's efforts to
establish net-zero carbon hydrogen
as a key pillar in an emerging clean
energy economy. Most gas turbines
and natural gas engines available
today can operate on hydrogen mixtures
ranging 10% to 40% depending
on the manufacturer and model. All
major turbine and engine manufacturers
are on track to have 100%
hydrogen-compatible systems commercially
available by 2030 or earlier,
and many existing systems will
be able to upgrade to 100% hydrogen
with field modifications.
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ASHRAE JOURNAL ashrae.o rg
Finally, the respondents state, " We
feel that the advantages of renewably
generated electricity powering
efficient, all-electric buildings far
outweigh the long-term carbon
emissions of CHP systems, however
efficient they might be. " Electrifying
buildings is a good thing where it
makes sense. However, is electrifying
buildings the only thing that
makes sense? We believe the pathway
to a zero-carbon future will
require a broad mix of solutions,
and CHP, the most efficient way to
generate power and thermal energy,
will play a critical role in reducing
GHG reduce emissions now and in
the future.
Richard S. Sweetser, Life Member ASHRAE, Herndon, Va.;
Bruce Hedman, Ph.D., Alexandria, Va.
Increasing
Ventilation In
1980s High-Rise
Commercial
Office Buildings
The article " Increasing Ventilation
in 1980s High-Rise Commercial
Office Buildings " by Jamie
Kono, P.E., Associate Member
ASHRAE; Jim Gieselman, P.E., BEAP,
Member ASHRAE; Meghan Kara
McNulty, P.E., Member ASHRAE;
Barry Abramson, P.E., BEAP, Life
Member ASHRAE, that appeared in
the November 2022 issue of ASHRAE
Journal contains some eye-opening
data regarding the indoor air quality
that exists in a good portion of
today's buildings.
I agree that existing buildings need
to evaluate methods of increasing
ventilation rates as the most effective
means of mitigating airborne
F E B R U A RY 2023
particles and improving the overall
indoor air safety. However, it
is important to keep in mind the
other major challenge we face today,
reducing energy consumption.
Simply increasing ventilation will
certainly result in an increase in air
safety, but at the cost of additional
energy use.
As an alternative, I offer " Option
3A " : incremental, floor-by-floor
retrofits to provide additional
ventilation through a total energy
recovery wheel.
Tyler Mancl, P.E., Associate Member ASHRAE,
Scofield, Wis.
The Authors Respond
We agree that energy recovery can
play an important role in achieving
the dual goals of improved indoor
air quality and energy efficiency-
and not only for the incremental
approach, but for all design options.
In our article, we aimed to shift the
conversation from, " Can we do this
[drastically increase ventilation
rates]? " to, " How can we do this? "
As we move forward with decarbonizing
the built environment, the
next question must be, " How can
we do this efficiently? " Perhaps a
discussion of annual energy use for
each option would make for a good
follow-up article
Jamie Kono, P.E., Associate Member ASHRAE, Atlanta;
Jim Gieselman, P.E., BEAP, Member ASHRAE, Atlanta;
Meghan Kara McNulty, P.E., Member ASHRAE, Atlanta;
Barry Abramson, P.E., BEAP, Life Member ASHRAE, Atlanta
ASHRAE Journal welcomes letters
to the editor. The letters
should be no more than 250
words and must relate to an article
published in ASHRAE Journal.
Please send your letters to
rebecca@ashrae.org.
http://ashrae.org
ASHRAE Journal - February 2023

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