Inside ASHE - Fall 2017 - 42

Feature

STILL BATTLING REHEAT
ENERGY IN HOSPITALS:
Short- and long-term ideas for
hospitals' biggest energy use
By Timothy M. Peglow, MBA, MSE, associate vice president, Patient Care and Prevention Facilities, MD Anderson; Jeff Boldt, LEED AP, HBDP,
director of innovation and quality, IMEG Corp; and Travis R. English, PE, LEED AP, MBA, director of engineering, Kaiser Permanente NFS
Facilities Planning and Design
ccording to the latest
Commercial Building Energy
Consumption Survey
(CBECS), reheat energy is
still the largest energy
use in U.S. hospitals.
"Reheat" is heating previously cooled air:
cool the air down, then heat it up again.
Reheat is heat energy that is not related
to how cold it is outside.
Eliminating reheat is an exercise in
lean thinking and lean principles. Every
space should use the least amount
of cooling and heating it can to meet
desired conditions, each hour of the
year. Any excess cooling or excess air
flow in systems increases reheat. The
never-ending challenge is to find reheat
and reduce or eliminate it.
Reheat is tough to reduce in hospitals,
even when using the best HVAC and
control technology. This article lists
strategies for both the short and longer
term. By applying these strategies,
MD Anderson reduced steam use by
50 percent.

Reducing reheat, right now
* Watch. Refine automation system
displays so they show how much
heating or cooling occurs at each
terminal device. This tells the staff
whether spaces are at maximum
heating or cooling before making
system adjustments.
* Verify valve positions. For systems
with reheat, check that heating
42 INSIDE ASHE | FALL 2017

and cooling valves close when
commanded. Just checking the
commanded signal is not enough.
Look at the temperatures around
the valves, manually or through a
building automation system (BAS). If
temperatures drop or increase when
the system says a valve is closed, it
is probably not closed. Investigate
it. Finding those valves eliminates
wasted energy.
Checking can be done with a
monitoring-based commissioning
tool. These tools are on the rise in
availability. One common feature of
monitoring-based commissioning
packages is an ability to diagnose
large data sets and point out
valves to investigate.
* Reset cooling air temperatures.
Reset cooling supply air temperatures
based on dehumidification and/or
comfort needs. This requires trial and
error to find optimum values and
algorithms. Good algorithms typically
include observing space temperatures
and variable air volume (VAV) box
positions. To ensure a sequence works
well, do some spot-checks of space
humidity. Energy codes like ASHRAE
90.1 require some supply temperature
reset controls. They sometimes also
require temperature and fan speed
controls. However, energy codes and
standards are not always enforced, and
sometimes they lack exact sequences,
so owners should verify controls.

Most importantly, regularly
verify functionality. During
retrocommissioning work, one
co-author found reset sequences
to be routinely overridden and
non-functional in buildings just
12 months after initial commissioning.
* Reset hot water temperatures.
Another way to reduce reheat is to
reduce hot water temperatures. In hot
weather, hot water temperatures in
many facilities can be reduced to as
low as 100°F to 120°F. One successful
strategy is to create a sliding scale of
heating temperatures that increases
only when outdoor air is below 50°F.
Resetting hot water temperatures
saves energy for many reasons.
In summer, much heat is lost
through piping lines. If a facility
uses condensing boilers, their
highest efficiencies are at low
water temperatures. A lower water
temperature can enable use of heat
pump chillers (see the section on heat
pump chillers under the longer-term
strategies portion of this article).
Like reset sequences on supply
air, hot water resets should
be commissioned fully and
reconfirmed routinely.
* Standardize. A standard set of
field-tested sequences could be a
big benefit. ASHRAE's GPC-36 is not
yet published, but public review
copies are available (ASHRAE 2016).
Several of the strategies in GPC 36



Table of Contents for the Digital Edition of Inside ASHE - Fall 2017

Letter from the president
What’s new
Pop quiz
The measurement of a health care facility manager: How do you define success?
Creating a program to identify and monitor pressure dependent spaces
Critical considerations for specifying a building automation system for health care
Bright ideas: LED renovation at Boulder Community Health
Selecting the right fire extinguisher for operating rooms
Still battling reheat energy in hospitals: Short- and long-term ideas for hospitals’ biggest energy use
The financial impact of variable speed ventilation controls in hospital kitchens
Data driven culture fuels University of Florida Health’s success in energy and operational optimization
Energy management in a critical access hospital: How Barnesville Hospital reduced energy consumption by 39 percent
Value analysis: Improving operating margin through cost savings
Member spotlight
Advertisers’ index
Inside ASHE - Fall 2017 - Intro
Inside ASHE - Fall 2017 - bellyband1
Inside ASHE - Fall 2017 - bellyband2
Inside ASHE - Fall 2017 - cover1
Inside ASHE - Fall 2017 - cover2
Inside ASHE - Fall 2017 - 3
Inside ASHE - Fall 2017 - 4
Inside ASHE - Fall 2017 - 5
Inside ASHE - Fall 2017 - 6
Inside ASHE - Fall 2017 - 7
Inside ASHE - Fall 2017 - 8
Inside ASHE - Fall 2017 - Letter from the president
Inside ASHE - Fall 2017 - What’s new
Inside ASHE - Fall 2017 - 11
Inside ASHE - Fall 2017 - Pop quiz
Inside ASHE - Fall 2017 - 13
Inside ASHE - Fall 2017 - 14
Inside ASHE - Fall 2017 - 15
Inside ASHE - Fall 2017 - 16
Inside ASHE - Fall 2017 - 17
Inside ASHE - Fall 2017 - The measurement of a health care facility manager: How do you define success?
Inside ASHE - Fall 2017 - 19
Inside ASHE - Fall 2017 - Creating a program to identify and monitor pressure dependent spaces
Inside ASHE - Fall 2017 - 21
Inside ASHE - Fall 2017 - 22
Inside ASHE - Fall 2017 - 23
Inside ASHE - Fall 2017 - Critical considerations for specifying a building automation system for health care
Inside ASHE - Fall 2017 - 25
Inside ASHE - Fall 2017 - 26
Inside ASHE - Fall 2017 - 27
Inside ASHE - Fall 2017 - Bright ideas: LED renovation at Boulder Community Health
Inside ASHE - Fall 2017 - 29
Inside ASHE - Fall 2017 - 30
Inside ASHE - Fall 2017 - 31
Inside ASHE - Fall 2017 - 32
Inside ASHE - Fall 2017 - 33
Inside ASHE - Fall 2017 - Selecting the right fire extinguisher for operating rooms
Inside ASHE - Fall 2017 - 35
Inside ASHE - Fall 2017 - 36
Inside ASHE - Fall 2017 - 37
Inside ASHE - Fall 2017 - 38
Inside ASHE - Fall 2017 - 39
Inside ASHE - Fall 2017 - 40
Inside ASHE - Fall 2017 - 41
Inside ASHE - Fall 2017 - Still battling reheat energy in hospitals: Short- and long-term ideas for hospitals’ biggest energy use
Inside ASHE - Fall 2017 - 43
Inside ASHE - Fall 2017 - 44
Inside ASHE - Fall 2017 - 45
Inside ASHE - Fall 2017 - The financial impact of variable speed ventilation controls in hospital kitchens
Inside ASHE - Fall 2017 - 47
Inside ASHE - Fall 2017 - 48
Inside ASHE - Fall 2017 - 49
Inside ASHE - Fall 2017 - 50
Inside ASHE - Fall 2017 - 51
Inside ASHE - Fall 2017 - Data driven culture fuels University of Florida Health’s success in energy and operational optimization
Inside ASHE - Fall 2017 - 53
Inside ASHE - Fall 2017 - 54
Inside ASHE - Fall 2017 - 55
Inside ASHE - Fall 2017 - Energy management in a critical access hospital: How Barnesville Hospital reduced energy consumption by 39 percent
Inside ASHE - Fall 2017 - 57
Inside ASHE - Fall 2017 - Value analysis: Improving operating margin through cost savings
Inside ASHE - Fall 2017 - 59
Inside ASHE - Fall 2017 - Member spotlight
Inside ASHE - Fall 2017 - Advertisers’ index
Inside ASHE - Fall 2017 - 62
Inside ASHE - Fall 2017 - cover3
Inside ASHE - Fall 2017 - cover4
Inside ASHE - Fall 2017 - outsert1
Inside ASHE - Fall 2017 - outsert2
Inside ASHE - Fall 2017 - 70
Inside ASHE - Fall 2017 - 71
Inside ASHE - Fall 2017 - 72
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Inside ASHE - Fall 2017 - 74
Inside ASHE - Fall 2017 - 75
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