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Modeling buildings’ energy use is an effective strategy for identifying energy saving potential and seeking for energy efficient building solutions. However, there exist significant challenges for such modeling, particularly of high-rise buildings. The aim of this paper is to examine such challenges drawing on the case of high-density high-rise office buildings in the hot and humid climate of Hong Kong. The challenges are examined in relation to four aspects, namely, modeling approach, modelling tools, data availability and atmospheric conditions. A framework of strategies is developed for addressing the challenges. The strategies are then illustrated through a case study with a hypothesized high-rise office building in Hong Kong. Essential to achieving accuracy of modeling buildings’ energy use are found to be the collection and verification of building information and specification of thermal zones and schedules for modeling. The lack of usable data of energy use in high-rise buildings is considered to be a major barrier to verifying modeled results. To establish an integrated model with energy modelling and CFD software should effectively address the challenges. [ABSTRACT FROM AUTHOR]

Abstract: A city's reliance on energy increases when it is developed. Moreover, the combustion of fossil fuels inevitably generates air pollutants including carbon dioxide, nitrogen oxides, sulfur dioxide, particulate matter, and others. Combining with other anthropogenic air pollutants, visibility in many Asian cities including Hong Kong have deteriorated rapidly in the past decades. This paper explores the relationships between energy use, meteorological factors, and change in visibility in Hong Kong using long-term time-series data. The total use of primary energy increased from 146,700 TJ in 1971 to 1,270,865 TJ in 2011 while the number of hours of reduced visibility increased from 184 h to 1398 h during the same period of time. Bivariate correlations show that poor visibility was significantly associated with energy use and annual mean air temperature. Multiple regression analysis indicates that the burning of aviation gasoline significantly, adversely affect visibility. Results illustrate that the number of clear days in Hong Kong will decrease, in particular due to the increase in air traffic. [Copyright &y& Elsevier]

Climate change issues and building energy use implications in subtropical Hong Kong were examined. A total of 40 years (1961–2000) of measured hourly temperature data were gathered and analysed. Three different parameters were examined, namely mean temperature, cumulative frequency of occurrence and cooling degree days (CDD). It was found that there was an underlying trend of temperature rise in recent years. Such temperature increase tended to occur more frequently during the winter period and mid-season than the summer months. The slight increase in CDD during the last 20 years suggested that cooling requirements and, hence, energy use for air conditioning might be affected if the trend persisted. The frequency of occurrence analysis, however, revealed no significant changes in the outdoor design conditions, and peak building cooling loads were expected to remain unchanged. This paper presents the work and discusses the energy use implications. [Copyright &y& Elsevier]

This paper firstly presents a case study on analyzing the electrical load profiles recorded in a Hong Kong hotel over a period of 12 months to examine the potential energy saving opportunities (ESOs) in its building services installations. The case study is followed by a report of the survey results of energy and water use in 36 quality hotels in Hong Kong. Finally, a regression analysis where the surveyed energy and water use data were correlated to a number of hotel background or operational parameters to search for suitable energy and water use performance explanatory indicators is presented. The survey results depict a diversified energy and water use situation in Hong Kong’s hotels, but the regression analysis indicates that, while some of the correlations obtained are weak, there do exist a few strong energy and water explanatory indicators. [Copyright &y& Elsevier]

This paper reports on a study of energy use in 16 quality hotels in Hong Kong. An overview of energy use in these hotels is firstly presented, and this is followed by a detailed analysis of energy use in one of the 16 hotels. The overview indicates that the energy use situation in hotels in Hong Kong is very much diversified. The total energy use in a hotel is dominated by electricity, with the greatest portion for air conditioning because of sub-tropical climate. A detailed multiple variable regression analysis indicated that a number of hotel operating parameters as well as climatic condition can affect electricity, diesel and gas use in a hotel building. In order to achieve both operating cost saving and environmental protection, it is recommended that an energy management programme be established, and key elements of such a programme based on the experience of implementing energy conservation strategies in hotels in Hong Kong are highlighted. [Copyright &y& Elsevier]

The rapid growth of energy consumption in buildings has become an alarming threat to the climate. Various building-level energy saving measures have been studied and adopted to achieve energy efficiency. However, high-rise public residential buildings in subtropical climate as an important contributor to building-level energy consumption have received insufficient attention of research. The aim of this paper is to analyse the energy use of high-rise residential buildings in subtropical climate and examine the impacts of different energy saving measures for developing strategies for achieving very low-energy high-rise buildings. A typical high-rise (40-storey) public residential building in Hong Kong was selected as the case building, which has the energy use intensity of 106.6 kWh/m2 for the total building area and of 153.8 kWh/m2 for the area inside the residential units. The energy model of the case building developed using EnergyPlus software was carefully calibrated using metered energy use data and expert consultations adopting a systematic approach. Sensitivity analyses were then conducted using the parametric analysis tool jEPlus to quantify the impacts of different energy saving measures on energy use intensity reduction. It was found the measures in relation to human behaviours have the largest impact, followed by building service system efficiency and renewable energy. Building form and building envelope have the modest impact. The findings enhance the knowledge of subtropical high-rise public residential buildings' energy performance, and the developed and calibrated energy model could be used to explore more strategic energy saving measures in the long term. The quantified impacts of the measures should inform design decisions of low-energy housing production in high-rise sectors. • A 40-storey building is examined with energy use 153.8 kWh/m2 for residential area. • Energy model uses EnergyPlus software with sensitivity analyses tool jEPlus. • Behaviours have largest impact on energy use, then building services and renewables. • Building form and envelope have the modest impact on energy use reduction. • Systemic strategies are suggested for very low-energy high-rise residential buildings. [ABSTRACT FROM AUTHOR]