ASHRAE Journal - December 2021 - 46

ASHRAE TECHNOLOGY AWARD CASE STUDIES
a building energy performance dashboard was created
in 2017 to monitor the performance data continuously.
The key objective of the digital platform is to use the
latest technology to improve work and operation effi -
ciency. The platform is customizable, and the facility
management team can tailor-make charts and reports
to suit their operation needs. The digital platform
automatically collects and analyzes the operation data
and prepares dashboard, charts and regular reports
(Figure 1). This greatly reduces the time spent in report
processing and improves the work effi ciency.
Through data analysis, various insights had been
found to optimize the building operation. Some strategies
include chilled water pressure setpoint reset and
chilled water temperature setpoint reset. The platform
also helps to smartly monitor and maintain the operation
performance through benchmarking.
IAQ and Thermal Comfort
A building environmental performance dashboard
(BEPD) was built for 2PP in 2018. The platform is a
real-time monitoring system to monitor temperature,
humidity, CO2 and PM2.5 inside the shopping mall at 10
strategic locations; this also allows management to take
swift action if needed. An IoT gateway was established
in which IAQ sensors can communicate via wireless
network, with the data being able to be displayed at the
dashboard. By using IoT protocol, new IAQ sensors can
be easily connected to the network with the convenience
of network extension.
Data extracted from the BEPD showed that indoor average
CO2 concentration in 2PP Mall was 692 ppm, with
average outdoor CO2 concentration at 410 ppm, and the
indoor average temperature was 23.4°C (74.1°F), which
demonstrates good ventilation performance as well as
indoor thermal comfort as recommended by ASHRAE
Standard 62.1-2013 and ASHRAE Standard 55-2017.
A BEPD for IAQ is to be implemented for the 2PP Offi ce;
however, through the BMS we collected the indoor temperature
from 682 VAV boxes on 10 different fl oors and
found that more than 80% of investigated offi ce areas
have achieved thermal comfort under ASHRAE Standard
55-2017 assuming 0.5 clothing value (clo). According to
the BMS data of offi ce areas, fresh air rate of 11.8 L/s per
person (25 cfm) (assuming 4,116 occupants in the offi ce
area) is provided, which is higher than the required 8.5
L/s per person (18 cfm), per ASHRAE Standard 62.1-2013.
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During lunch hour and overtime work hours, the fresh
air rate is decreased to refl ect the lower occupancy rate
and to save energy.
The IAQ results of 2PP is not only used to monitor the
air quality but as an indicator to determine when to
conduct AHU fi lter replacement. We use MERV 11 fi lters
(adhering to ANSI/ASHRAE Standard 52.2-2017, Method
of Testing General Ventilation Air-Cleaning Devices for Removal
Effi ciency by Particle Size) in our AHUs, and although the
minimal removal effi ciency of PM2.5 is only 65%, the
data showed that the PM2.5 concentration before and
after the fi lter replacement resulted in a 27% reduction
of PM2.5 concentration. Through analyzing the IAQ data
with the help of the BEPD, good occupant health and
wellness can always be monitored and maintained.
Other than the IAQ monitoring in the front of house
area, IAQ measurement has also been conducted in the
toilet area by engaging a third-party professional test
laboratory, tested to the ANSI/ASHRAE/ASHE Standard
170-2017, Ventilation of Health Care Facilities, standard.
Although no explicit requirement exists for the toilet
area, the IAQ measurement results refl ected that the
total bacteria count in the toilet environment is excellent
and is to the standard recommended by American
Conference of Governmental Industrial Hygienists committee,
i.e., <500 colony-forming units/m3 (14 colonyforming
units/ft3). These IAQ measurements help the
facility management team review the toilet cleaning
management and ensure the highest quality of service is
maintained.
Operation and Maintenance
Data Analysis and Retro-Commissioning
With the use of the above-mentioned digital platform,
highly effi cient operation could be monitored and
maintained. The water transfer factor (WTF), which is
defi ned as the ratio of distributed cooling load to pump
consumption, is one of the examples adopted to evaluate
the operation performance. To achieve at least a
WTF of 50 at the end of 2017, we optimized the operation
strategy for chilled water pumps in 2PP by operating an
additional secondary chilled water pump at low speed
instead of operating one pump at full speed.
The WTF of chilled water pumps increased by approximately
15% using the new control logic and was maintained
through continuous monitoring. The WTF of
condensing water pumps increased by approximately
2021
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ASHRAE Journal - December 2021

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