ASHRAE Journal - April 2022 - 9
LETTERS
i.e., inlet side of the coil. Some
would prefer both control valves
on the return side. Some prefer the
control valves on the supply side for
both chilled water and hot water.
I noted the author did not get into
the details of piping at the central
equipment and at the coils, as is evident
from the diagrams.
Another point to be raised, which
does have to do with the piping at
the coils, is that chilled water cooling
coils are piped in a counterfl ow
confi guration for maximum heat
transfer, and heating coils are to be
piped in a parallel fl ow confi guration
for maximum heat transfer and
coil freeze protection. This requirement
will add to the piping at the
combination cooling-heating coil.
Charles Kryksman. P.E. LEED AP BD+C
Life Member ASHRAE, New York
The Author Responds
Thank you for your interest. The
option of using both coils in an AHU
for cooling during summer, or the
option of using a single coil for cooling
or heating as needed in an AHU,
can provide cost-effective solutions
for existing and new HVAC systems.
It can offer new methods to integrate
heat pumps in VAV systems,
leading to decarbonization and electrifi
cation of our future buildings.
Yes, the methods can be applied
for water-cooled chiller plants as
well. You can read advanced confi
gurations tailored specifi cally for
water-cooled chillers in this issue
starting on page 12.
In the February article, I give an
example of two air-cooled chillers
and condensing boilers with specifi c
sizes. The numbers are presented
as an example and are intended
just to give estimations for the cost
savings that may obtained from the
proposed four design and control
options.
More data and analysis with various
building and equipment sizes
will be a subject for future work.
Option 3 and Option 4 will be
implemented and deployed in real
HVAC systems installed in the HVAC
lab at the University of Cincinnati.
Control valve locations and coil confi
gurations are important points that
could be addressed in future studies.
Nabil Nassif, P.E. Ph.D.,
Member ASHRAE, Cincinnati
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A P R I L 2 0 2 2 ashrae.org ASHRAE JOURNAL
9
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ASHRAE Journal - April 2022
Table of Contents for the Digital Edition of ASHRAE Journal - April 2022
Contents
ASHRAE Journal - April 2022 - Intro
ASHRAE Journal - April 2022 - Cover1
ASHRAE Journal - April 2022 - Cover2
ASHRAE Journal - April 2022 - 1
ASHRAE Journal - April 2022 - Contents
ASHRAE Journal - April 2022 - 3
ASHRAE Journal - April 2022 - 4
ASHRAE Journal - April 2022 - 5
ASHRAE Journal - April 2022 - 6
ASHRAE Journal - April 2022 - 7
ASHRAE Journal - April 2022 - 8
ASHRAE Journal - April 2022 - 9
ASHRAE Journal - April 2022 - 10
ASHRAE Journal - April 2022 - 11
ASHRAE Journal - April 2022 - 12
ASHRAE Journal - April 2022 - 13
ASHRAE Journal - April 2022 - 14
ASHRAE Journal - April 2022 - 15
ASHRAE Journal - April 2022 - 16
ASHRAE Journal - April 2022 - 17
ASHRAE Journal - April 2022 - 18
ASHRAE Journal - April 2022 - 19
ASHRAE Journal - April 2022 - 20
ASHRAE Journal - April 2022 - 21
ASHRAE Journal - April 2022 - 22
ASHRAE Journal - April 2022 - 23
ASHRAE Journal - April 2022 - 24
ASHRAE Journal - April 2022 - 25
ASHRAE Journal - April 2022 - 26
ASHRAE Journal - April 2022 - 27
ASHRAE Journal - April 2022 - 28
ASHRAE Journal - April 2022 - 29
ASHRAE Journal - April 2022 - 30
ASHRAE Journal - April 2022 - 31
ASHRAE Journal - April 2022 - 32
ASHRAE Journal - April 2022 - 33
ASHRAE Journal - April 2022 - 34
ASHRAE Journal - April 2022 - 35
ASHRAE Journal - April 2022 - 36
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ASHRAE Journal - April 2022 - Cover3
ASHRAE Journal - April 2022 - Cover4
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