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GSR 2015 - Buildings and Appliances

116 06 ENERGY EFFICIENCY: RENEWABLE ENERGY’S TWIN PILLAR BUILDINGS AND APPLIANCES The building sector accounts for about one-third of global final energydemand.7 About40%oftheenergyconsumedinbuildings is used to provide space heating and cooling, with the remainder going to other end-uses, such as water heating, lighting, and operating appliances.8 Vast opportunities exist to reduce energy use in buildings while improving comfort, such as: optimisation of building orientation and design to maximise the benefits of passive solar energy (e.g., for heating and daylighting); reduced thermal bridging; advanced glazing; improved air tightness; increased thermal mass, which improves a building’s ability to absorb and store heat; and improved ventilation.9 In recent years, more focus has been placed on taking a holistic approach to improving building energy performance, rather than on raising the efficiency of individual systems.10 This means addressing all the aspects of efficient building design in a way that best optimises overall performance in a given geographical location and in the most cost-effective manner. Examples of building standards include Energy Star in the United States and the Passivhaus Standard, which is a common benchmark for high building energy performance, predominantly in Europe. By definition, passive houses have very low energy demand and provide high levels of thermal comfort without the use of conventional heating or cooling technologies.11 In Europe alone, the number of such buildings tripled between 2000 and 2012, with Germany and Austria leading this growth.12 Net zero energy buildings (NZEBs) and nearly zero energy buildings (nZEBs) are those in which energy demand is greatly reduced through efficiency improvements, and all (or nearly all, in the case of nZEBs) remaining energy needs are satisfied with renewable energy.13 New NZEBs are inaugurated every day in numerous countries, providing evidence that NZE performance is achievable in a variety of locations and climates.14 Emerging NZEB-related trends and lessons include: ◾◾ Public buildings are being used increasingly to demonstrate the feasibility of nZE and NZE, helping to educate people about potential benefits. In North America, public buildings account for two-thirds of existing NZE projects, and US public benefits programmes have resulted in successful pilot NZEBs in Oregon and California.15 ◾◾ Large NZE buildings (with floor area of 5,000 m16 or greater) are becoming more common.17 ◾◾ Architects around the world are becoming more familiar with nZE design. In 2014, the International Union of Architects agreed unanimously to adopt the 2050 Imperative, committing member organisations (which represent more than 1.3 million architects in 124 countries) to 100% nZE design by 2050.18 ◾◾ North America has demonstrated that NZE performance is not restricted to new construction; 24% of verified NZE buildings in the region comprise renovation projects.19 The focus on existing buildings for NZE/nZE projects and targets is rising, most notably in several EU countries. ◾◾ Projects are more frequently expanding beyond single buildings, with the overall energy balance measured for a portfolio of neighbouring buildings or an entire district under a common NZE target. In North America, for example, there are 18 NZE districts, including U.S. Army facilities and several universities.20 ◾◾ Although most of the existing NZEB projects are located in developed countries, pilot NZEBs have been built in several developing countries and emerging economies, including China, Kenya, Malaysia, and Taiwan.21 ◾◾ Additional investment costs for NZEBs (in comparison to similar conventional buildings) are estimated in the range of 5–19%. Return on investment for energy efficiency, without subsidy, is estimated to be 5–12%.22 The efficiency of a building is determined predominantly by its design and systems, including heating and cooling. Heat pumps—whether air-, ground-, or water-sourced—can be an efficient technology for meeting heating and cooling needs. Between 2011 and 2014, the global market for heat pumps grew from approximately 1.5 million units to 2 million units, driven largely by Asia, and in particular China.23 Heat pumps have the potential to provide some renewable energy content for heating and cooling in buildings. (p See Sidebar 4, GSR 2014.) Synergies exist, as it is far easier to meet heating and cooling demand with heat pumps if buildings have efficient envelopes; the same applies for solar thermal and modern biomass systems. Appliances and electronics used within a building complete the picture. Large appliances—such as refrigerators, washing machines, and dryers—are responsible for a significant share of residential electricity consumption.24 Due to efficiency improvements, the energy consumption of large appliances has declined rapidly. Energy use in refrigerators, for example, decreased from a range of 450–800 kWh per year in 1996 to 250–400 kWh per year in 2011 (refrigerators in the EU demonstrated the highest efficiency throughout this period).25 Televisions (and computer monitors) also have experienced significant efficiency advances over the past decade, including the replacement of cathode ray tubes (CRTs) with flat panel technologies (liquid crystal display (LCD) and plasma display panel (PDP)); the transitions from analog to digital and from cold cathode fluorescent lamp (CCFL) backlights to light-emitting diode (LED) backlights; and the adoption of power management systems for televisions.26 Among technologies commercially available in 2015, the most efficient models have demonstrated energy savings in the range of 32–71% compared to conventional CCFL backlit LCD televisions.27 Between 2010 and 2014, global shipments of less-efficient CCFL-LCDs decreased by almost 90%, while those of LED-LCDs increased eightfold.28

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