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Energy consumption has dramatically increased in buildings over the past decade due to population growth, more time spent indoors, increased demand for building functions and indoor environmental quality, and global climate change. Building energy use currently accounts for over 40% of total primary energy consumption in the U.S. and E.U. Nevertheless, significant energy savings can be achieved in buildings if they are properly designed, constructed and operated. For this reason, building energy efficiency can provide key solutions to energy shortages, carbon emissions and their serious threat to our living environment. This paper offers a brief overview of building energy-consumption situations, relevant energy-saving approaches, and the influence of global climate change. Building energy-consumption situations based on data derived from international energy reports are initially compared between the U.S., China and the E.U. Both similarities and differences are found in aspects of building energy end-uses and final energy fuel-types among these top three building energy consumers. We then introduce the current concept of the zero-energy building (ZEB). State-of-the-art approaches for ZEB technologies are summarized in three categories: passive energy-saving technologies, energy-efficient building service systems and renewable energy production technologies. The feasibility of these technologies is reviewed. In addition, we briefly discuss the influence of global climate change on the evolution of building energy use in the future. We find that climate change significantly impacts building energy performance, particularly in space heating and cooling. Improvements on building envelope and ventilation can play an important role in reducing space heating and cooling consumption levels. We also provide some suggestions for further developing ZEBs. [ABSTRACT FROM AUTHOR]

Buildings account for 40% of total global energy consumption. The International Energy Agency (IEA) and the European Commission (EC) are attempting to achieve an 80% reduction in global emissions by 2050. The objectives of this paper are to identify the refurbishment scenario with the lowest environmental impact using Life Cycle Assessment (LCA) and to assess the scenario’s robustness to future climate change scenarios using a sensitivity analysis. We applied and verified the proposed approach in a residential case study of a reference project located in Kapfernberg, Austria. The environmental assessment included two façade refurbishment proposals (minimum and high quality with respect to energy), onsite energy generation (using solar thermal collectors and photovoltaic (PV) panels), one renewable future energy mix and the effects of climate change according to the Austrian Panel on Climate Change (APCC). The environmental indicators used in the assessment were the cumulative energy demand non-renewable (CED n. ren.), global warming potential (GWP) and ecological scarcity (UBP) over building life cycles. The results indicated that a high-quality refurbishment of the thermal envelope with prefabricated façade elements, including solar thermal collectors and PV panels, represented the optimal refurbishment. In terms of the environmental indicators, the high-quality refurbishment scenario is always beneficial throughout the building’s life cycle. Additionally, the sensitivity analysis of the high-quality refurbishment scenario found an increasing production of surplus electricity with increasing PV area. This surplus of energy provides greater benefit in the short term with the current energy mix. Once the energy from the grid is shifted to renewable sources, the added benefit is decreased. Therefore, it is necessary to find an optimal balance between diminishing returns due to changes in the future energy mix and the financial investment made over the lifetime of the building, especially for plus energy buildings. However the findings from this specific case study need to be evaluated for other refurbishment cases, taking into account future local climate change and energy supply mix scenarios in other regions. [ABSTRACT FROM AUTHOR]

As power systems integrate more intermittent renewable generation, and as extreme weather events become more frequent with climate change, power systems are likely to require increasing amounts of spinning reserves in order to maintain reliable operation. While traditionally spinning reserves have been supplied by generators, demand-side resources can also provide reserves by increasing or decreasing consumption in response to system needs. As a major contributor to peak system loads, air conditioning equipment is a promising source of demand-side spinning reserves. Through building energy modeling and simulation, this paper demonstrates, for the first time, the technical feasibility of providing spinning reserves by curtailing air conditioning systems in commercial buildings, while maintaining occupant comfort by providing cooling from thermal storage. The economic benefits to the building owner are shown to be attractive, primarily due to capacity payments in the spinning reserves market. Furthermore, it is possible for a building equipped with thermal storage to participate in both frequency regulation and spinning reserves markets for more economic benefits as spinning reserves are less frequently deployed. [ABSTRACT FROM AUTHOR]