IEA EBC annex 53: Total energy use in buildings—Analysis and evaluation methods
Introduction
Globally the building sector consumed more than one-third of the total primary energy. Improving energy efficiency in buildings to reduce energy use and green-house-gas emissions is a proven key strategy to mitigate global climate change. Although building technologies have advanced significantly in last decades, one of the most significant barriers to substantially improving the energy efficiency of buildings is the lack of knowledge about the factors determining the energy use. There is often a significant discrepancy between the designed and real total energy use in buildings. The reasons for this divergence are poorly understood and often have more to do with the role of human behavior than the building design. This discrepancy leads to misunderstanding and miscommunication between the parties involved in the topic of energy savings in buildings.
In fact, building energy consumption is mainly influenced by six factors: (1) climate, (2) building envelope, (3) building services and energy systems, (4) building operation and maintenance, (5) occupant activities and behavior and (6) indoor environmental quality provided. The latter three factors, related to human behavior, can have an influence as great as or greater than the former three [1], [2], [3]. The user-related aspects and behavior effects can be seen from the large spread in energy use for similar or identical buildings, but a distinction between the building-related and the user-related energy consumption cannot be established. It is necessary to investigate all six factors together to understand building energy consumption data. Detailed comparative analysis of building energy data, concerning the six factors mentioned above, would provide essential guidance to identify opportunities to save energy.
Aiming to advance the knowledge in the field and develop and apply methods to analyze and evaluate total energy use in buildings and its driving factors, a group of about 100 researchers from 15 countries gathered together and worked from January 2009 to March 2013 on the Annex 53 project, under International Energy Agency’s (IEA) Energy in Buildings and Communities (EBC) Programme. Annex 53 was organized into four subtasks and one taskforce: (1) Subtask A − Definition and reporting, (2) Subtask B − Case Studies and Data Collection, (3) Subtask C − Statistical Analysis, (4) Subtask D − Energy Performance Evaluation, and (5) Task force − Occupant behavior.
Annex 53 employs an interdisciplinary approach, integrating building science, architectural engineering, computer modeling and simulation, and social and behavioral science. The ultimate goal of Annex 53 is to better understand and strengthen knowledge regarding the robust prediction of total energy usage in buildings, thus enabling the assessment of energy-saving measures, policies, and techniques. This annex studies how occupant behavior influences building energy consumption in order to bring occupant behavior into the building energy field so as to develop building energy research, practice, policy, etc. more closely aligned with the real world. The research was performed on two building types: residential buildings (detached houses and multi-family apartments) and office buildings (large scale high rise offices and small scale offices). The main objectives of Annex 53 were to develop and demonstrate the following:
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Definitions of terms related to energy use and the influencing factors of building energy use
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An approach to describing occupant behavior quantitatively and to setting up a model for occupant behavior
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Database of energy use and influencing factors for existing typical buildings in different countries
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Methodologies and techniques for monitoring total energy use in buildings including hardware and software platforms
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A statistical model for national or regional building energy data including the influence of occupant behavior
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Methodologies to predict total energy use in buildings and to assess/evaluate the impacts of energy saving policies and techniques
This paper highlights main research methods, findings, and outcomes of Annex 53, drawing some content from Annex 53’s published reports [4], [5], [6], [7], [8], [9], [10].
Section snippets
Influencing factors on building energy use
Energy use in buildings is mainly influenced by six factors as defined in Annex 53, see Fig. 1. These factors may be organized into two groups of factors that can be classified as physical and human influenced. The first group of factors are technical and physical factors, because their origin is related to building envelope, climate, building service systems, and other issues that cannot be easily changed during building operation by humans. Even though they can be changed during building
Building energy data definition and energy reporting
Inconsistency in the terminology related to building energy use is a serious barrier to understand the influencing factors on building energy use and to analyze real energy use. Therefore, a starting and highly necessary point with the Annex 53 was definitions of terms to describe total energy use in buildings, energy boundary, conversion factors, and energy performance indicators. This was highly important to enable comparability of datasets and expressions of building energy performance. The
Case studies and data collection
Description and the main findings from the case studies of office and residential buildings are presented here. The main idea in the data collection was to organize information according to the definitions and data framework explained in Section 3. In total data on 13 office and 12 residential buildings from seven countries were collected. The locations of the case studies are given in Fig. 3, while the climate data for the corresponding seven locations are given in Fig. 4. In Fig. 3, the case
Online data collection systems and technologies
Monitoring is crucial to better understanding the energy behavior of buildings. New automated meter reading technology combined with modern information and communication technologies are overcoming previous data deficiencies. Millions of smart meters are being installed. In addition, fast-evolving sensor technologies with wireless and other communication capabilities offer cheap means for complementing energy data collection with measurements of various environmental factors. However, there are
Statistical analysis
There is great potential for applying statistics in the field of total energy use. A more accurate prediction of both building and user energy-related behavior may result in benefits for energy savings, cost saving, as well as improving the comfort of the indoor environment. The main fields of application for statistical analysis are: (1) Energy diagnosis for individual buildings, (2) Measuring energy use, targeting, and benchmarking for large building stocks, and (3) Trends in energy policies
Occupant behavior in residential buildings and office buildings
Energy-related occupant behavior refers to observable actions or reactions of a person in response to external or internal stimuli, or actions or reactions of a person to adapt to ambient environmental conditions. These actions may be triggered by various driving forces, which can be separated into biological, psychological, and social contexts, time, building/installation properties, and the physical environment. Information on occupant presence and activities can be obtained from individual
Summary of main outcomes and findings
Annex 53 made significant contributions to a better understanding of how to robustly analyze and predict the total energy use in buildings, thus enabling the improved assessment of energy–saving measures, policies and techniques. The definitions of terms related to energy use and the influencing factors of building energy use are developed for office buildings and residential buildings, which provide a uniform language for building energy performance analysis. On this base, database of case
Acknowledgments
This paper summarizes and highlights main research activities, outcomes and findings from Annex 53, drawing content from Annex 53’s final reports and related publications. The authors appreciate strong leadership and technical contribution of subtask leaders, as well as contributions from all participants of Annex 53. The IEA (International Energy Agency) Energy in Buildings and Community (EBC) Programme (iea-ebc.org) carries out research and development activities toward near-zero energy and
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