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To achieve a more comfortable indoor environment while still retaining low energy consumption level is an exciting challenge for designers and owners of buildings. In this paper, a silica-aerogel filled super-insulating glazing system was proposed. A numerical study was conducted to analyze the energy performance and visual performance of the proposed glazing system. Two popular building simulation programs namely EnergyPlus and Radiance were applied in the numerical study. In the study of the energy performance, three control strategies (space temperature control, operative temperature control and PMV control) were applied to simulate the occupant’s control behavior toward the air-conditioning system in reality. The result indicated that compared with conventional single clear glazing, the silica aerogel glazing could retain a 4% longer thermally comfort period, while the energy consumption of HVAC system was reduced by 4–7%. The performance of the silica aerogel glazing was almost equal to that of the state-of-art low-e glazing. It is also concluded that as the occupant’s request on thermal comfort got stricter, the performance of the silica aerogel glazing would became better. In the visual comfort point of view, it can be concluded that the glare effect and near-window bright zone could be reduced significantly while indoor illumination level still met the requirement. [ABSTRACT FROM AUTHOR]

Abstract: In Hong Kong, conventional air-conditioning (AC) systems cause a high energy consumption and poor indoor thermal comfort. This paper investigated the AC load profiles of three typical local commercial buildings, i.e. office, hotel and retail, and examined the energy consumption of liquid desiccant cooling system (LDCS) for these buildings. Simulation results showed that the cooling load contributed to more than 98% of total annual load, with high latent load proportion from March to September. The high reheating ratio, i.e. from 60% to 90%, is found to be the main reason for the poor thermal comfort. Therefore, the LDCS which could handle sensible and latent loads separately was proposed. However, the electricity-driven LDCS was found not suitable for local commercial buildings. significant energy saving could be achieved by the solar-assisted LDCS system with thermal storage, when the installation area for solar collectors is larger than the minimum required one, i.e. 9.7m2/(kWm−2) for office and 12.7m2/(kWm−2) for hotel buildings. Energy saving of different system types with different installation areas was also studied. The solar-assisted LDCS shows more energy saving in winter but less in summer. Results and conclusions can be useful for researchers and local engineers. [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]