Energy Efficiency and Energy Consumption in Buildings: Objectives, Requirements

Transcription

1 Energy Efficiency and Energy Consumption in Buildings: Objectives, Requirements Daniel Grecea Lecture 17: 23/03/2017 European Erasmus Mundus Master Course Sustainable Constructions under Natural CZ-ERA MUNDUS-EMMC

2 Introduction Buildings are key to a sustainable future because their design, construction, operation, and the activities in buildings are significant contributors to energyrelated sustainability challenges reducing energy demand in buildings can play one of the most important roles in solving these challenges. The buildings sector and people s activities in buildings are responsible for approximately 31% of global final energy demand, approximately one-third of energy-related CO2 emissions, approximately two-thirds of halocarbon, and approximately 25 33% of black carbon emissions. Several energy-related problems affecting human health and productivity take place in buildings, including mortality and morbidity due to poor indoor air quality or inadequate indoor temperatures. More efficient energy and material use, as well as sustainable energy supply in buildings, are critical to tackling the sustainability-related challenges.

3 Introduction (2) Recent major advances in building design, know-how, technology, and policy have made it possible for global building energy use to decline significantly. A number of low-energy and passive buildings, both retrofitted and newly constructed, already exist, demonstrating that low level of building energy performance is achievable. With the application of on-site and community-scale renewable energy sources, several buildings and communities could become zero-net-energy users and zero-greenhouse gas (GHG) emitters, or net energy suppliers. Recent advances in materials and know-how make new buildings that use 10 40% of the final heating and cooling energy of conventional new buildings cost-effective in all world regions and climate zones. Holistic retrofits 2 can achieve 50 90% final energy savings in thermal energy use in existing buildings, with the cost savings typically exceeding investments.

4 Introduction (3) The constructed scenarios, demonstrate that a reduction of approximately 46% of the global final heating and cooling energy use in 2005 is possible by This is attainable through the proliferation of today s best practices in building design, construction, and operation, as well as accelerated state-of-the-art retrofits. This is achievable while increasing amenity and comfort and without interceding in economic and population growth trends and the applicable thermal comfort and living space increase. It goes hand in hand with the eradication of fuel poverty i.e., supplying everyone with sufficient thermal comfort.

5 Introduction (4) Final building heating and cooling energy demand scenarios until 2050: stateof-the-art (~corresponding roughly to the GEA Effi ciency set of pathways) and sub-optimal (~corresponding roughly to the GEA Supply set of pathways) scenarios, with the lock-in risk (difference).

6 Almost 60% of the world s electricity is consumed in residential and commercial buildings. At the national level, energy use in buildings typically accounts for 20 40% of individual country total final energy use, with the world average being around 30%. Per capita final energy use in buildings in a cold or temperate climate in an affluent country, such as the United States and Canada, can be 5 10 times higher than in warm, low-income regions, such as Africa or Latin America (see Table). Table: Contribution of the buildings sector to the total fi nal energy demand globally and in selected regions in 2007

7 Further information on the characteristics of building energy use by region or representative countries Building final and primary energy use in selected countries in 2003; AEC = annual energy consumption

8 Total final energy use in buildings per capita in different world regions, according to the International Energy Agency (IEA) statistics Total annual final energy use in the residential and commercial/public sectors, building energy use per capita by region and building type in 2007 (kwh/capita/yr).

9 Final energy use per square meter for thermal comfort by world region and building type, according to input data collected from different sources Final heating and cooling specific energy consumption by region and building type in 2005 (kwh/m2/yr).

10 Figure demonstrates that five energy services accounted for 86% of primary energy use in buildings in These were: (1) thermal comfort space conditioning that includes space heating, cooling and ventilation 36%; (2) illumination 18%; (3) sanitation and hygiene, including water heating, washing and drying clothes, and dishwashing 13%; (4) communication and entertainment electronics including televisions, computers, and office equipment 10%; and (5) provision of food, refrigeration and cooking 9%. The remaining 14% includes residential small electric devices, heating elements, motors, natural gas outdoor lighting, and commercial service station equipment, telecommunications equipment, medical equipment, pumps, and combined heat and power in commercial buildings. Primary energy use in US commercial and residential buildings in 2010

11 A review of national level studies of household energy services, analyzed on a life cycle basis, is presented. Share of consumption categories in total energy use based on life-cycle analysis or input-output calculation and rate of annual energy use in kilowatt per capita (numbers on top of the columns).

12 Buildings-related energy use contributes 60 70% of the total household energy use in OECD countries and up to 90% in India. Share of end-uses (by appliance) in electricity consumption in Delhi, India.

13 Differences in per capita energy use among six developed countries, at similar affluence levels Residential energy use in different developed countries. HDD = heating degree day.

14 A similar result is illustrated by a study of energy use for home air conditioning in a residential building in Beijing. The building consists of 25 home units, all with similar income characteristics. Electricity consumption of air-conditioning in 25 flats of a residential building in Beijing.

15 In India and China, urban households tend to have higher energy requirements than rural households. In China, moving from a rural to an urban life currently increases household demand for energy by about a factor of three (Table), while in developed countries, urban households tend to have lower energy requirements. By 2020, both rural and urban demand for energy will increase due to a combination of urbanization, a shift from biomass to commercial energy carriers, and increased income. Thus, Chinese urban energy use per household in 2020 is expected to be five times the amount of rural energy per household today. Increasing energy intensities when moving from rural to urban life in China.

16 Trend of specific building energy use in the United States during the second half of the twentieth century, for Japan since 1970, and the trend for China since the mid-1990s. Trend of total building final energy use per m2 in the United States ( ) and in Japan ( ) (kwh/m2/yr) as compared to China.

17 Distribution of fuels in total final energy use in the residential and commercial sectors worldwide. Note that residential energy use (81.3 EJ) exceeds commercial and public sector energy use (27.5 EJ) by a factor of three. World total final energy consumption by fuel in the residential (left) and commercial and public (right) sectors in 2007.

18 Overview of the direct and indirect energy use of the average household in the United States in 2002, from the life cycle perspective. Indirect energy use is split into energy losses and indirect energy connected to the purchase of all other goods and services. The largest category is private transport. The second largest category is utilities, which includes direct energy use and the provision of water and wastewater treatment. The third largest category is the indirect energy embodied in food purchased by households. Direct and indirect primary energy use of the average US citizen in 2002 for different consumption purposes.

19 The greenhouse gas emissions caused by the production of information and communication technology and audiovisual equipment purchased by Norwegian households is larger than the emissions caused by the electricity this equipment uses, even assuming a relatively polluting electricity mix. GHG emissions associated with the purchase, use and disposal of electric and electronic equipment in Norwegian households, assuming 0.56 kgco 2 -eq/kwh for use-phase electricity (EU average).

20 The Energy Base building in Vienna, is another example of energy use in good practice. The glazing on the south façade is slightly overhanging to increase the proportion of diffuse to direct sunlight entering the room, while the incorporation of PV panels and reflective blinds enhances daylighting. Photograph of the energy base building in Vienna (left) and schematic diagram of the ventilation, solar-preheating, and heat recovery system (right).

21 In central Europe there is a progressive decline in the cost of the additional investment required to meet the Passive House standard, which uses four to eight times less heating energy than conventional new housing. Learning curve showing the progressive decrease in the incremental cost of meeting the passive house standard for the central unit of row houses.

22 Comparison of component costs for a building with a conventional VAV mechanical system and conventional (double-glazed, low-e) windows with those for a building with radiant slab heating and cooling and high-performance (triple-glazed, low-e, argon-fi lled) windows, assuming a 50% glazing area/wall area ratio. Prices given in 2001 Canadian dollars.

23 There are many examples where old buildings that have been retrofitted to very high energy performance standards. Table includes cases where 90% or more savings in heating energy use have been achieved. Documented examples of deep savings in heating energy use through renovations of buildings. Adjusted to an indoor temperature of 20.

24 Global building heating and cooling final energy use will increase by 33% by 2050 as compared to 2005 instead of decreasing. Since buildings are constructed or renovated for very long periods, this represents a significant lock-in 79% of 2005 total global heating and cooling final energy demand in this case as it is not feasible or is extremely uneconomic to capture the remaining energy savings opportunities outside of renovation and construction cycles. Documented examples of deep savings in heating energy use through renovations of buildings. Adjusted to an indoor temperature of 20.

25 In the state-of-the-art scenario, most regions are able to decrease final thermal energy use in buildings, with the largest drop in OECD countries (73%), followed by emerging economies (66%). Space heating and cooling final energy use in the five aggregate GEA regions, , in state-of-theart and sub-optimal scenarios for the five regions: heating and cooling final energy use development for scenarios (i.e., assuming sub-optimal renovation and construction energy performance levels).

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31 Results on cumulative investments and energy cost savings by 2050 for the different GEA regions of the world. Cumulative undiscounted investment costs and energy cost savings in different regions and worldwide, US 2005 $ trillion.

32 Graphical representation of the efficiency scenario Appliance electricity demand in base case and high efficiency scenario.

33 Energy is typically a small proportion of total operating costs for buildings. For example, in a high quality office building in Germany, heating and electricity made up less than 5% of the total running cost of the building about 1.1 out of every 23.3 (1.4 out of US 2005 $29.8) spent. Average values of total costs by quality of fittings.

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