ASHRAE Journal - April 2022 - 62

ASHRAE TECHNOLOGY AWARD CASE STUDIES
of fi ndings, recommendations, actions and
results are detailed here.
Example #1. The air handler night setback
sequence at ECTC's Academic Technical
Building had " requests required to run " set
to two zones. These two zones-namely the
entryway and lobby-were consistently out
of range during setback times, forcing the
AHU and chillers to run more than necessary
during unoccupied times. The sequence
was updated to require fi ve zones to be out of
range to enable setback operation, resulting
in nearly $9,000 per year in savings.
FIGURE 2 CEMCS vendor neutral data collection infrastructure.
HVAC
Controller
Vendor A
BACnet
BAS Data Pump
HVAC
Controller
Vendor B
BACnet
BAS
Front End
Indoor Air Quality and Thermal Comfort
Among the different measures identifi ed, multiple
measures improved the indoor air quality (IAQ)
and thermal comfort of buildings. Two examples of
the CEMCS Support Services fi ndings that led to IAQ
improvements follow.
Example #2. Four variable air volume air-handling
units (AHUs) serve the Humanities Building at ECTC.
Three relative humidity sensors are placed throughout
the building in representative spaces. In the existing
setup, each AHU was tied to a single sensor and
controlled for relative humidity independently, even
though all AHUs served overlapping common spaces.
The fourth AHU had no associated humidity sensor in
this orientation and was not set up for humidity control.
The remaining AHUs were set to 55°F (13°C) supply air
temperature (SAT) when their respective space humidity
exceeded 60%. The sequence was updated to coordinate
all four AHUs to respond to high humidity conditions. If
any sensor rose above a 60% relative humidity threshold,
all AHUs would respond by lowering the SAT to 55°F
(13°C) until the space humidity levels were satisfi ed.
By addressing humidity control more effectively, this
sequence update saved ECTC $3,300 in utility costs
through reduced equipment run times and enhanced
the occupant comfort.
Example #3. The outdoor air (OA) dampers on three
rooftop units at MCTC's Montgomery Building were not
functioning properly, and the zones they serve were not
receiving adequate ventilation. The dampers were not
following the minimum OA setpoint and were not opening
to economize. The facility service contractors were
alerted, and the damper actuators were repaired.
62
ASHRAE JOURNAL ashrae.o rg A P R I L 2 0 2 2
Innovation
Converting data into action would not be possible
without a robust data collection system. CEMCS is completely
BAS-vendor neutral system. Data acquisition for
all of KCTCS's building automation data follows one of
two fully automated paths (Figure 2).
Once the BAS information has landed in its respective
staging table, CEMCS compiles the data and populates
the database to be accessible to the user via the CEMCS
front end. The front end includes automated fault detection,
diagnostic trends and ad hoc reports. The data is
kept permanently, in some cases going back a decade. In
total, the KCTCS CEMCS system currently collects data
from 125,000 points across 140 buildings.
Operation and Maintenance
Monthly meetings with the facility maintenance team
were implemented to share fi ndings of maintenance
issues discovered from CEMCS data. These meetings
gave the maintenance staff an opportunity to discuss
existing facility issues with engineers that designed
their facilities. The ongoing communication between
the facility maintenance team and engineers who had a
holistic understanding of their facilities was a highlight
of the program for the college maintenance staff.
Example #4. The supply fan for an AHU-4 at JCTC's
Chestnut Hall was running full-speed for months due
to static pressure and temperature control issues. This
dual-duct AHU was programmed to control to the worstcase
static pressure sensor between the hot deck and
cold deck. The hot deck supply duct static pressure sensor
was blocked by a failed fi re damper in the mechanical
room, making it the worst-case sensor and forcing
CEMCS
Application Server
BAS Trend Export
CEMCS
Database Server
Direct Export
2022
SOURCE: KEVIN FULLER, IDS
http://ashrae.org
ASHRAE Journal - April 2022

Table of Contents for the Digital Edition of ASHRAE Journal - April 2022
