ASHRAE Journal - October 2023 - 27

HONORABLE MENTION 2023 ASHRAE TECHNOLOGY AWARDS
Building Envelope
A low window-to-wall ratio of 0.35 and glazing with
a low shading coefficient of 0.29 were adopted, which
were 46% and 55% lower than the baseline building
model set to achieve an overall thermal transfer value
(OTTV) barely meeting the threshold stipulated in the
Code of Practice for Overall Thermal Transfer Value
in Buildings issued by the Buildings Authority of
Hong Kong.
The OTTV of 14 W/m2 (1.3 W/ft2) was achieved, which
was about 58% less than the statutory requirement. A
vertical green wall was constructed on the west façade
to enhance the building performance by reducing heat
gain from the western exposure. Shading fins were also
installed to avoid excessive solar radiation, taking the
sun's path into consideration.
Chilled Water Supply from District Cooling System (DCS)
The KERHQ cooling plant receives its chilled water
supply from a highly energy-efficient centralized
district cooling plant located at the Kai Tak district,
which distributes chilled water to KERHQ through a
network of thermally insulated underground chilled
water pipes for space cooling. The DCS supply side
underground chilled water pipes terminate on the
DCS consumer side at the DCS substation located at
KERHQ. In normal operation, the DCS plant would
be the primary chilled water source, and variable
chilled water pumps distribute the chilled water for
both nonessential and essential air-conditioning
loads. In case of DCS plant failure, total energy heat
pumps (TEHP) and the associated chilled water pumps
backed up by diesel generator would be the sole chilled
water source, which takes up 100% of the essential airconditioning
load of the critical users' facilities.
Renewable Energy System
A solar hot water system for preheating domestic
hot water and a photovoltaic (PV) system for electric
power generation were installed in KERHQ. In 2021,
the annual energy generated by solar collector panels
and PV panels was about 63,000 kWh and 13,500 kWh,
respectively.
Indoor Air Quality
The design of the ventilation rate followed the
CASE STUDY
requirements of ASHRAE Standard 62.1-2016. The
air-conditioning system design not only adopted
the demand-control principle to achieve energy
conservation, but also maintained the acceptable
standard of ventilation requirement. In the parking
garage, carbon monoxide and nitrogen dioxide sensors
were installed to monitor the respective concentration
to control the operation of the ventilation fan via a
central control monitoring system for energy savings.
Design for Manufacture and Assembly (DfMA)
To promote the adoption of innovative technology in
the construction industry, KERHQ took the initiative
in implementing DfMA in the TEHP room. The
project performance on productivity, workmanship,
environmental protection and site safety was enhanced
relative to a conventional construction approach.
Operation and Maintenance
System reliability was one major design consideration
to minimize system downtime for this building that
is operated 24 hours a day. Sufficient resilience was
provided to avoid single point of failure. The main and
essential chilled water risers were interconnected by
bypass pipes to enhance reliability. Metering facilities
such as digital power analyzers and energy meters
connecting to the building energy monitoring system
were adopted to facilitate energy monitoring, energy
audits and retro-commissioning.
Cost Effectiveness
The analysis of energy data indicated that various
EEFs and RETs adopted in KERHQ were effective for
the purposes of energy conservation and reduction
of building operation cost. The annual electricity
consumption of KERHQ in 2021 was about 20% less
than the estimated electricity consumption of the
building simulation model under BEAM Plus, which
is Hong Kong's leading initiative to offer independent
assessment of building sustainability performance.
Apart from the EEFs and RETs, KERHQ adopted DCS
water source for heat rejection, and the building owner
was no longer required to install, operate, maintain and
replace their own chillers. Hence, the up-front capital
cost and subsequent maintenance cost for the airconditioning
plant were reduced.
Ken C.K. Yeung is chief building services engineer, H.L. Tang is a senior project manager, and Allison Y.M. Law is a project manager in the Architectural Services Department in Hong Kong, China.
O CTO B ER 2023 ashrae.org ASHRAE JOURNAL
27

http://www.ashrae.org

ASHRAE Journal - October 2023

Table of Contents for the Digital Edition of ASHRAE Journal - October 2023