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To mitigate the climate change issue, the Government of the Hong Kong Special Administrative Region (HKSAR) proposed the "Hong Kong Climate Change Plan 2030+" with an ambitious goal of reducing the carbon intensity to 65%–70% below 2005 levels by 2030. To achieve this target, the HKSAR Government has developed two District Cooling Systems (DCS) to promote the use of district energy system, enhancing the overall energy efficiency for cooling purpose. One of the government-owned DCSs is located at the Hong Kong-Zhuhai-Macao Bridge Hong Kong Port (HZMB-HKP), producing a total design cooling capacity of 24.16 MW to passenger clearance building and ancillary buildings there. This paper demonstrates how the DCS at HZMB-HKP could enhance overall energy efficiency for cooling purpose, through proper chiller sequencing control, and reduce CO2 emission significantly. An optimal seasonal chiller operation mode is also suggested to be adopted at the DCS at HZMB-HKP from cost-effectiveness perspective. Practical application: District Cooling Systems are considered as a promising solution to alleviate the climate change issue. An optimized chiller sequencing control strategy of DCS can effectively reduce overall cooling energy consumption, so as to achieve carbon neutrality. This paper outlines a case study on a cost-effective operational control strategy of the DCS at HZMB-HKP. The analysis of both the theoretical and practical sequencing control strategy can be taken as a reference for DCS development in the future. [ABSTRACT FROM AUTHOR]

• Automatic MiC envelopes and layout generation by a novel SSG-MOO method. • Multi-objective optimization formulation for passive MiC design. • A pilot MiC study in Hong Kong produced 5 selected Pareto optima out of 625. • Up to 0.42% energy savings and 9.71% spatial daylight autonomy improvement against the baseline. • A multi-level analysis of results and design strategies for practitioners. Modular-integrated Construction (MiC) is an emerging construction technique promoted in the building sector for high productivity and low waste emission in the construction phase; yet, the standardized modules also bring new challenges, such as balancing passive energy efficiency and spatial daylight autonomy, to the operational phase. This paper proposes a Symmetric Skeleton Grammar-based Multi-Objective Optimization (SSG-MOO) method to formulate parametric MiC envelopes and detailed layout, with the two objective functions being energy efficiency and interior daylight performance in the operational phase. Pareto optima of the SSG-MOO, computed by the Non-dominated Sorting Genetic Algorithm II, are generally verified and analyzed in three levels, i.e., MOO's solution space, SSG layout, and MiC design parameters. A case study of MiC residential building in Hong Kong demonstrated the SSG-MOO method through five new passive MiC designs (i.e., spatial reorganization of three architectural modules, and parameter tuning of the envelops and corridors), achieving up to 0.42% energy savings and 9.71% spatial daylight autonomy improvement compared to the baseline design. The contribution of this paper is two-fold, including a novel and sound SSG-MOO formulation for parametric MiC designs, and offering time-efficient and evidence-based design tactics for MiC designers and industrial practitioners to push boundaries of MiC. [ABSTRACT FROM AUTHOR]

In this paper, we study the recent energy use intensity (EUI) in kWh/m2/year of Hong Kong's secondary schools. We found a 22% increase of EUI from, 2003 (86 kWh/m2/year) to 2017 (105 kWh/m2/year) approximately. It may be due to the increase in the number of air-conditioned classrooms. We then use a novel two-stage regression-based approach to analyse the most important set of statistically significant energy performance factors. Then, the energy use intensity (EUI) is normalized with these energy performance factors to find the benchmarking scores used to assess whether the electricity tariff affects schools' energy efficiency. In the first stage of the approach, we first conduct three methods of fitting regression models, backward, forward, and stepwise (OLS), to find a set of normalized factors and construct the benchmarking model. The first stage provides the normalized EUI range, approximately between 50 and 163 kWh/m2/year. In the second stage, if better goodness of fit is desired in the second stage, convex nonparametric least squares (CNLS) regression analyses are employed with the same set of normalized factors. This two-stage regression-based approach is called the OLS-CNLS approach. Using simple EUI (kWh/m2/year) results, we find that high tariff schools' energy efficiency is better than low tariff schools. However, the benchmarking scores (normalized EUIs) of the OLS-CNLS approach show that the null hypothesis cannot be rejected. The energy efficiency of high tariff schools is not significantly better than that of low tariff schools. It implies that the tariff level is not a crucial factor associated with secondary schools' energy efficiency in Hong Kong. As the OLS-CNLS approach allows us to take all the significant energy performance factors into consideration to address the electricity tariff concern, the funding/budget policies probably motivate the school management to look for better EUI. • HK secondary school kWh/m2/yr increases to 105 in 2017 from 85 in 2002. • OLS-CNLS are proposed for developing benchmarking models. • OLS-CNLS is an enhanced regression-based method comparing with CNLS. • Benchmarking results show the insignificance of electricity tariff to EUI. [ABSTRACT FROM AUTHOR]

Energy consumption of lift systems is one key issue in modern high-rise buildings, drawing property owners' attention and accounting for 6% of total electricity consumption by end-use in Hong Kong. A Benchmarking Energy Performance Indicator (BEPI), , measured in J.kg−1.m−1 and proposed by the first author of this paper for lift installations is mentioned in the Technical Guidelines of the Building Energy Code , as one emerging good engineering practice. BEPI is a fair parameter for comparing energy performance of lifts irrespective of their brand, model, travel, speed, capacity and control. It considers energy performance due to both the motor drive efficiency and traffic control intelligence. However, one main obstacle to make it statutory is the lacking of a generic monitor able to retrieve three sets of real time data (normally unavailable on an existing lift) to compute the BEPI, namely energy consumption, instantaneous car load and traveling distance, and to collect ample data statistically reliable enough to determine an acceptable threshold value. This paper describes the development of a proof-of-concept prototype BEPI monitor by giving full technical details on the rationale and history of development, the hardware components, software framework, and updated numerical results of one implementation inside the headquarters of Electrical & Mechanical Services Department (EMSD) of HKSAR. Experiences in installing and calibrating those external sensors that make the whole system non-disturbing to normal lift operation, as well as the procedures in computing the BEPI, are discussed in greater details. It has been shown that the BEPI is traffic dependent but the weekly average of it is relatively stable, confirming it may be robust enough for benchmarking purpose. The solution described in this paper may help roll out the monitoring of BEPI for all lifts inside and outside Hong Kong. [ABSTRACT FROM AUTHOR]

Abstract: Energy consumption by passenger transport in Hong Kong increased rapidly in the past decades and in 2008 it accounted for 19.7% of total energy use. Improving energy efficiency has been widely regarded as an effective way for reducing energy use in the transport sector. However, the expected energy savings from energy efficiency improvement are likely to be discounted due to the existence of rebound effect. This paper employs econometric models to estimate the direct rebound effect for private passenger transport in Hong Kong. We find that the magnitudes of the direct rebound effect are respectively 45% and 35% for 1993–2009 and 2002–2009, which indicates that there was a declining trend in the direct rebound effect for passenger transport over time. It also indicates that the direct rebound effect needs to be taken into consideration in assessing the impact of energy efficiency measures on reducing energy use in Hong Kong. [Copyright &y& Elsevier]

Abstract: Hong Kong is located in a typical subtropical region. The buildings in Hong Kong are subjected to high cooling demands for their air-conditioning systems throughout most of the year, and their contribution toward the total energy consumption is about 40%. Therefore, energy efficiency in buildings is essential to reduce the global energy use and improve the local environmental sustainability. This paper provides an overall review of the building energy research and efforts in Hong Kong over the last decade. Various aspects and energy saving measures, including energy policy, energy audit, design, control, diagnosis, building performance evaluation and renewable energy systems, studied or used to enhance the energy efficiency in buildings are reviewed. A brief introduction of the Hong Kong Building Energy Codes (BEC) and Hong Kong Building Environmental Assessment Method (HK-BEAM) are also provided to present the efforts of the local government and community on energy efficiency in buildings. This review aims at providing building researchers and practitioners a better understanding of buildings energy saving opportunities and approaches in cities particularly in subtropical regions and taking further proper actions to promote buildings energy efficiency and conservation. [Copyright &y& Elsevier]

Abstract: A benchmark study of the energy efficiency of private office buildings in Hong Kong was conducted in 2002 because energy efficiency was declining. In the study, private office buildings were divided into five user groups. For each group, a multiple regression model was developed to find the relationship between Energy Use Intensities (EUIs) and other factors, such as operating hours, for normalization and benchmarking purposes. In this paper we make use of the regression results to study the energy efficiency of private office buildings by different grades. In Hong Kong, office buildings are divided into three grades (A, B, and C) based on the quality of the facility, which is reflected in rental values; a Grade A office building denotes expensive luxury. We found that the EUI of Grade A office buildings is the highest, consuming over 50% of the total energy used in office buildings. Recently, the annual EUI of office buildings has improved even though Grade A floor space is increasing. This may be due to the promotion of the energy efficiency program launched in the last decade. [Copyright &y& Elsevier]

Abstract: This paper reports the evaluations of energy efficiency, plume potential as well as plume control of a huge chiller plant using water-evaporative cooling towers for heat rejection for a super high-rising commercial office building in a subtropical region of Hong Kong. The evaluations were carried out in a dynamic Transient Simulation Program (TRNSYS)-based simulation platform using alternative control strategies including set-point control logics of the supply cooling water temperature and cooling tower fan modulation control methods as well as different number control means of cooling towers. The results show that different control strategies have significant effects on the energy efficiency of the chiller plant. The quantification of the energy efficiency demonstrates significant energy-saving potential by using advanced technologies for implementing optimal control strategies in this cooling system. The results also reveal that the plume may occur frequently in spring and summer seasons and occasionally in other months due to the odd subtropical weather conditions. Control strategies also have significant effects on the frequency of the plume occurrence. The effective energy efficiency control and effective plume control using wet–dry (i.e., hybrid) cooling towers are also discussed. [Copyright &y& Elsevier]

The 'zero carbon building (ZCB)' approach has been hailed as an innovative strategy for addressing climate change and achieving a low carbon society. There has been burgeoning research on the technical aspects of ZCBs. However, the aspect of stakeholder engagement, albeit imperative for zero carbon development, has been largely overlooked in the literature. This paper examines stakeholder knowledge, attitude and practice (KAP) with regard to ZCBs in a systems manner, employing a new KAP model that integrates ontology, axiology and epistemology as the theoretical lens. The research was carried out through a questionnaire survey and focus group discussions with multiple stakeholders in the building industry in Hong Kong, which is a typical example of a high-density city. The results indicate the generally ambiguous and inconsistent knowledge, relatively negative attitude, and poor practice of stakeholders towards ZCBs. The statistical analysis findings reveal that differentiation exists between different stakeholder groups as to their knowledge, and this highlights the significant role that explicit ZCB knowledge plays in creating a knowledge-induced attitude that favours changes in practice leading to zero carbon developments. The applicability of the developed KAP model is verified using the case of Hong Kong, enabling the dialectics and complexities of stakeholder KAP towards ZCBs to be further clarified. Practical implications are provided to enhance the knowledge, shape the attitudes, and encourage the practices of building towards zero carbon in future cities. • Knowledge, attitude and practice (KAP) with regard to ZCB are systematically examined. • A KAP model that integrates ontology, axiology and epistemology of ZCB is developed. • There are gaps between practitioners and researchers regarding knowledge of ZCB. • Stakeholders in HK have relatively negative attitude and poor practice towards ZCB. • Well-structured knowledge is key to induce attitude and practice favoring ZCB. [ABSTRACT FROM AUTHOR]

The article applies a three-stage Slacks-Based Measure-Data Envelopment Analysis (SBM-DEA) pattern to examine the relationship between energy consumption and unfavorable CO2 emissions on green sustainable development, for the 11 cities of the Guangdong-Hong Kong-Macao Greater Bay Area (GBA) during 2010–2016, by going through various violated factors and stochastic disturbance. Labor, capital and energy resource are chosen as input variables, while GDP and CO2 emission as output variables. During the three phases consisting of the SBM-DEA model (first stage and third stage) and SFA analysis (second stage), CO2 emission is considered as an unfavorable outcome, while stochastic statistical disturbances and external environmental influences are identified. The results show that the average efficiency of the GBA cities is 0.708, with only Shenzhen, Macao SAR and Hong Kong SAR having an efficiency of 1 during the whole study period. Based on the findings, suggestions are made for the GBA cities' sustainable development aspects. [ABSTRACT FROM AUTHOR]