The following are publications developed under Task
Position Paper: Net Zero Energy Solar Buildings
IEA SHC Task 40: Position Paper
June 2015 - PDF 0.35MB - Posted: 2015-07-19
The aim of this Position Paper is to present the current status of the various research and pathways in designing and constructing net-zero energy buildings (NetZEBs). It is written to provide general information on this topic to policy and decision makers who may be in positions to facilitate the market uptake of NetZEB practices. The information therein draws from the work of the 82 National Experts from the 19 member countries that participated in the Task/Annex and have contributed so much knowledge to advancing this field.
Task 40: What Market Adoption of NetZEBs Need
May 2015 - PDF 0.08MB - Posted: 2016-03-20
Editor: Pamela Murphy
To mainstream market adoption of NetZEBs, what is needed is a wide consensus on clear definitions and agreement on the measures of building performance that could inform “zero energy” building policies, programs and industry building practices, as well as design tools, case studies and demonstrations that would support industry adoption.
Modelling, Design, and Optimization of Net-Zero Energy Buildings
March 2015 - Posted: 2015-02-27
By: Andreas Athienitis
Editor: William O'Brien
Building energy design is currently going through a period of major changes. One key factor of this is the adoption of net-zero energy as a long term goal for new buildings in most developed countries. To achieve this goal a lot of research is needed to accumulate knowledge and to utilize it in practical applications. In this book, accomplished international experts present advanced modeling techniques as well as in-depth case studies in order to aid designers in optimally using simulation tools for net-zero energy building design. The strategies and technologies discussed in this book are, however, also applicable for the design of energy-plus buildings. This book was facilitated by International Energy Agency?s Solar Heating and Cooling (SHC) Programme and the Energy in Buildings and Communities (EBC) Programme through the joint SHC Task 40/EBC Annex 52: Towards Net Zero Energy Solar Buildings R&D collaboration.
Development of an energy evaluation methodology to make multiplepredictions of the HVAC&R system energy demand for office buildings
May 2014 - PDF 4.88MB - Posted: 2014-06-23
By: Jinkyun Choa, Seungho Shina, Jonghurn Kimb, Hiki Hong
HVAC&R systems are the most energy consuming building services, representing approximately half of the final energy use in the building sector. Despite their significant energy use, there is a lack of a consistent and homogeneous framework to efficiently guide research, mainly due to the complexity and variety of HVAC&R systems, but also to insufficient rigor in their energy analysis. Quantifying the energy consumption characteristics of HVAC&R system is complicated, because the energy savings provided by this system depend on various factors. This research evaluates energy consumption characteristics of HVAC&R systems, with the aim of establishing a common idea for the analysis of building energy efficiency. The objective of this study is to develop an energy evaluation methodology and a simple simulation program that may be used by engineers and designers to assess the effectiveness and economic benefits of HVAC&R systems. Our approach deals with the concept of HVAC&R system energy use aggregation levels that are composed of subsystems. To carry out a techno-economical estimation of HVAC&R systems considering different types of subsystems, the matrix combination analyzed, and a total of 960 HVAC&R systems can be implemented for a large-scale office building. The methodology of energy analysis that was carried out in this study highlights how to plan and design toward utilizing the most effective HVAC&R systems.
Solution Sets and Net Zero Energy Buildings: A review of 30 Net ZEBs case studies worldwide
A report of Subtask C
May 2014 - PDF 11.74MB - Posted: 2014-06-23
By: François Garde and Michael Donn
This technical report gives a review of 30 fully documented net ZEBs case studies that have been
identified by the Sub Task C participants. It reports a compilation of all technical and non-technical
information of the 30 case studies that formed the foundation on which the analysis of Volume 3 of the
Source Book was based.
Task 40 Highlights 2013
Towards Net--Zero Energy Solar Buildings
February 2014 - PDF 0.18MB - Posted: 2014-03-03
Energy use in buildings worldwide accounts for over 40% of primary energy use and 24% of greenhouse gas emissions. Several International Energy Agency (IEA) countries have adopted a vision of so-called ‘net zero energy buildings’ as a longterm goal of their energy policies. However, what is missing is a clear definition and international agreement on the measures of building performance that could inform 'zero energy’ building policies, programs and industry adoption around the world.
Evaluation Tool for Net Zero Energy Buildings: Application on Office Buildings
March 2013 - PDF 0.29MB - Posted: 2013-03-11
By: Annamaria Belleri, Federico Noris, Ulrich Filippi Oberegger, Roberto Lollini
Within the research project “IEA SHC Task 40 – ECBCS Annex 52: Towards Net Zero Energy Solar Buildings” an excel-based tool was developed to assess balance, operating costs and load match index for predefined selected Net ZEB definitions . The tool can be of assistance for different stakeholders, including building designers (evaluation of building design solutions with respect to different Net ZEB definitions), energy managers (assess the balance in monitored buildings) and policy makers (assist in the upcoming implementation process of Net ZEBs within the national normative framework).
Task 40 Highlights 2012
January 2013 - PDF 0.54MB - Posted: 2013-02-10
Energy use in buildings worldwide accounts for over 40% of primary energy use and 24% of greenhouse gas emissions. Several International Energy Agency (IEA) countries have adopted a vision of so-called ‘net zero energy buildings’ as a long-term goal of their energy policies. However, what is missing is a clear definition and international agreement on the measures of building performance that could inform ‘zero energy’ building policies, programs and industry adoption around the world.
Net Zero Energy Building
Living and Working with an Equalised Energy Balance
October 2011 - Posted: 2012-01-29
By: Karsten Voss, Eike Musall
Strategies and experiences from the perspective of planners and users: Net zero energy buildings, equilibrium buildings or carbon neutral cities – depending on location and the reasons for making the calculation, the numbers are run differently. The variety of terms in use indicates that a scientific method is still lacking – which is a problem not just in regard to international ommunication, but also with respect to planning processes as a response to energy challenges. The clarification and meaning of the most important terms in use is extremely important for their implementation.
ISBN: ISBN 978-3-920034-80-5
Order - 49.00 EUR
2011 - Posted: 2011-07-04
By: Karsten Voss and Eike Musall
Vol.1 Net Zero Energy source book in German-language
Towards Net Zero Energy
ECBCS Annex 52 Factsheet
2010 - PDF 3.49MB - Posted: 2011-03-28
The objectives of the project ‘Towards Net Zero Energy Solar Buildings’ are to study current net zero, near net zero and very low energy buildings and to develop a common understanding of a harmonised international definitions framework, tools, innovative solutions and industry guidelines. To achieve these objectives the project will document and propose demonstrations of practical net zero energy buildings (NZEBs) with convincing architectural quality.
Annex Final Revised: Towards Net Zero Energy Solar Buildings
February 2009 - PDF 0.1MB - Posted: 2009-03-13
By: Karsten Voss and Mark Riley
Energy use in buildings worldwide accounts for over 40% of primary energy use and 24% of greenhouse gas emissions1. Energy use and emissions include both direct, on-site use of fossil fuels as well as indirect use from electricity2, district heating/cooling systems and embodied energy in construction materials.
Towards Net Zero Energy
IEA SHC /ECBCS Project Factsheet
PDF 1.87MB - Posted: 2010-06-29
Energy Use in buildings worldwide accounts for over 40% of primary energy use and 24% of greenhouse gas emissions. Energy use and emissions include both direct, on site use of fossil-fuels and indirect use from electricity, district heating / cooling systems and embodied energy in construction materials. Several International Energy Agency (IEA) countries have adopted a vision of so-called ‘net zero energy buildings’ as longterm goal of their energy policies. However, what is missing is a clear definition and international agreement on the measures of building performance that could inform ‘zero energy’ building policies, programmes and industry adoption around the world.
Subtask A: Definitions and Implications
Analysis of load match and grid interaction indicators in net zero energy buildings with simulated and monitored data
September 2014 - Posted: 2014-10-01
By: Jaume Salom, Anna Joanna Marszal, Joakim Widén, José Candanedo, Karen Byskov Lindberg
The main objective of this paper is to contribute to the discussion on the role of Net Zero Energy Buildings (Net ZEBs) on future energy systems by the interplay between on-site generation and the building loads, often called load matching, and the resulting import/export interaction with the surrounding electricity grid, commonly named grid interaction. This investigation analyzes five case studies with high resolution data, three of which are based on real monitored buildings. The research aims at selecting and suggesting a limited set of quantitative indicators that: (a) can provide practical information for building as well as grid designers and operators, and (b) are understandable for a wider audience and do not require complex simulation tools or additional resources. This paper also presents novel graphical representations describing the yearly or daily variation of the indexes in an understandable manner.
It has been found that the hourly values of the cover factors (namely, the load cover factor and the supply cover factor) provide quite a good picture of the correlation between on-site demand and supply of energy. These factors illustrate both the daily and seasonal effect, the production pattern of different renewable energy technologies, and applied operation/control strategies. The loss-of load probability factor shows how often the on-site supply does not cover the on-site demand but it provides limited information. Several grid interaction indicators are presented in a normalized form based on the connection capacity between the building and the grid. The generation multiple is an index that compares peak values of exported/imported energy; it may also be used with generation/load values. The dimensioning rate and the connection capacity credit relate the building with the electrical grid. These indexes can be used to analyze individual buildings and extend their use in the case of cluster of buildings. Although some general trends have been identified in the results and the usefulness of these indicators is demonstrated, it should be noted that further studies are needed in order to define reference values for particular building topologies, clusters of buildings and climates, which could be used as a rule-of-thumb for grid/building designers.
Analysis of grid interaction indicators in net zero-energy buildings with sub-hourly collected data
August 2014 - Posted: 2014-08-25
By: Jaume Saloma, Joakim Widénb, José Candanedoc & Karen Byskov Lindbergd
This paper aimed to contribute to the discussion about the role of net zero-energy buildings (ZEBs) or nearly ZEBs in future energy systems, from the perspective of the resulting import/export interaction with the surrounding energy grid (commonly named grid interaction (GI)). This investigation analyses three buildings with measured data at sub-hourly time resolution. The goal of this paper was to quantify the effect of using high-resolution data (one or a few minutes) versus hourly resolution in the GI analysis of buildings with an on-site generation system. A limited set of quantitative GI indicators have been selected: the generation multiple, the dimensioning rate and the connection capacity credit. Additionally, this paper presents graphical representations describing in an intuitive way the yearly or daily variation of the indicators. Some general trends have been identified and the usefulness of the selected indicators is demonstrated. Findings show conclusively that sub-hourly analysis will give more accurate information. Differences between peak values measured with hourly and sub-hourly time resolution can be significant. If detailed GI analysis at the individual building level is required, one should consider going for detailed sub-hourly analysis. - $46.00 USD
Analysis Of Load Match and Grid Interaction Indicators in NZEB with High-Resolution Data
March 2014 - PDF 2.65MB - Posted: 2014-03-04
By: Jaume Salom, Anna Joanna Marszal, José Candanedo, Joakim Widén, Karen Byskov Lindberg, Igor Sartori
A Net Zero Energy Building (Net ZEB) is succinctly described as a grid-connected building that generates as much energy as it uses over a year. The “Net Zero” balance is attained by applying energy conservation and efficiency measures and by incorporating renewable energy systems. The main objective of this report is to analyze the usefulness and relevance of proposed Load Match and Grid Interaction (LMGI) for Net Zero Energy Buildings. The methodology is based in the analysis of available high-resolution data (mainly hourly) both from simulated and monitored Net ZEBs (Net Zero Energy Buildings) or nZEB (nearly Zero Energy Buildings). The central question is to find a limited set of indicators which provide relevant information to building owners, local grid Distribution System Operators (DSO) when information from building simulations are available at design stage.
Measurement and Verification protocol for Net Zero Energy Buildings
September 2013 - PDF 2.79MB - Posted: 2014-04-29
By: Federico Noris, Assunta Napolitano and Roberto Lollini
In recent years the movement towards more efficient and sustainable buildings has driven the building sector towards the adoption of Net Zero Energy Buildings (Net ZEB) concepts based on the basically zero external energy balance resulting from the renewable energy sources covering a great extent of the building loads. In this framework, the International Energy Agency (IEA) Task 40 / Annex 52 focuses on harmonizing definitions, developing tools, innovative solutions and guidelines related to Net ZEB. Most building energy performance certifications are currently issued on the basis of design input data and several important assumptions (e.g., weather conditions, user behaviors, management of the building) are made and often do not reflect the actual boundary conditions during operation. For this reason, it is necessary to carry out performance assessments during the operation phase on the basis of monitoring data. The current document summarizes the Measurement and Verification (M&V) protocol for Net ZEB developed within IEA Task 40/Annex 52 Subtask A. This report assists with the planning, implementation and data evaluation for Net ZEB monitoring. The document is divided in two main parts focusing on energy balance and indoor environmental quality (IEQ) assessment. The monitoring can be used to compare design versus real performance for building energy label verification or as a tool to further improve building performance. However, although the recognition of the cost-effectiveness (Mills and Matthew, 2009) of monitoring for many applications, measurement campaigns are not yet common because of the investment cost and the effort required during the different phases. A standardization of monitoring procedures will reduce the effort required in monitoring activities and therefore facilitate the diffusion. The purpose of defining a monitoring procedure to check the Net ZEB definition has one of the main goal to calculate the balance associated with the Net ZEB definition.
Fulfillment of net-zero energy building (NZEB) with four metrics in a single family house with different heating alternatives
September 2013 - PDF 2.13MB - Posted: 2013-10-25
By: Ayman Mohamed, Ala Hasan, Kai Sirén
This study aims to investigate the fulfillment of four Net Zero Energy Building (NZEB) balances, NZEB-PE, NZEB-site, NZEB-emission and NZEB-cost, considering the four metrics of primary energy (PE), site energy, CO2-eqemissions and energy cost, respectively, using weighting factors based on Finnish and international reference data. The study analyzes five conventional energy systems and seven biomassbased standalone and shared combined heat and power (CHP) systems. These systems are connected to a single family house located in Helsinki, Finland, with two energy efficiency levels: a standard house and a passive house, simulated by Trnsys software. The annual balance of the import and export of the operational thermal and electrical energies is applied. The simulated results indicate that the NZEB-emission, NZEB-PE, NZEB-cost, and NZEB-site are arranged in that order according to the ease of fulfilling the annual balance. Making the house high in thermal energy efficiency (or adding solar thermal collectors) for all the studied systems is a step towards achieving NZEB-PE, NZEB-cost, and NZEB-site. On the contrary, achieving the NZEB-emission by the shared CHPs connected to the standard house is easier than the passive house. The NZEB balance is more attainable by the shared CHPs than the standalone CHPs.
The NZEB-PE is easier to achieve using the international factors than using the Finnish PE factors.
LCE Analysis of Buildings - Taking the Step Towards Net Zero Energy Buildings
A Technical Report of Subtask A
May 2013 - PDF 0.21MB - Posted: 2013-05-31
By: By Björn Berggren1 and Monika Hall
Today a number of buildings exist for which the design principle has been to achieve a Zero Energy Building (ZEB) or Net Zero Energy Building (Net ZEB) [1-6]. This paper focuses on Net ZEBs. In Net ZEB definitions, there may or may not be a maximum limit on energy demand. The requirements are generally that the demand is covered by renewable energy sources and that the building is in compliance with the national standards and regulations. However, to meet the goal, a low demand gives an advantage. The general approach to reach Net ZEB could be described as a two-step concept. The first step is to reduce the energy demand by applying energy efficiency measures. The second step is to supply energy, generated by renewable sources, which may be supplied into an external grid when favourable [8-11].
Innovation development for highly energy-efficient housing: Opportunities and challenges related to the adoption of passive houses
March 2013 - PDF 3.91MB - Posted: 2013-10-16
By: Mlecnik, E.
In previous years we have seen a recognition of the significant potential that exists for reducing energy use through innovation in residential buildings. This study investigates innovation challenges and identifies opportunities that could lead to a rapid increase in the adoption of highly energy-efficient housing concepts, particularly that of the passive house. To this end, it exemplifies, interprets and develops the innovation adoption theory through an investigation of views and experiences on the supply side, the demand side and the policy side. It highlights successful innovation trajectories and barriers experienced by businesses. It addresses both problems and positive experiences from the perspective of the end user and investigates different policy approaches. As such, the research reveals important features of innovation-adoption strategies in the building sector. It shows how multi-player enterprise collaboration plays a key role, and the study also recommends the development of quality assurance schemes. It makes a valuable contribution to discussions about how active a role government policymakers and enterprise networks should play.
Net ZEB Evaluation Tool
November 2012 - Posted: 2013-01-19
By: Annamaria Belleri, Assunta Napolitano
The Net ZEB evaluation tool is an excel-based tool that enables energy balance, operating cost and load match index calculation for selected definition. It aims at evaluating solutions adopted in new building design with respect to different Net ZEB definitions (for building designers), assessing the balance in monitored buildings (for energy managers), and assisting the upcoming implementation process of Net ZEBs within the national normative framework (for decision makers).
Zero Energy Building Definition – A Literature Review
A Technical Report of Subtask A
September 2012 - PDF 0.17MB - Posted: 2012-09-19
By: Anna Joanna Marszal and Per Heiselberg
Results of this literature review are presented in two parts. First part presents key publications that significantly contribute to the discussion on ZEB definitions, and finally the discussion itself. In the second part, Appendix, the ZEB definitions from the literature are divided into the groups in order to give the reader an overview of the wide variety of ZEB definitions.
Net zero energy building: A review of current definitions and definition development in Belgium.
Subtask A: Definitions and Implications
June 2012 - PDF 0.27MB - Posted: 2012-07-04
By: Erwin Mlecnik, Shady Attia, Stefan Van Look
The recast of the European Performance of Buildings Directive (EPBD) requires the uptake of a definition of so called ‘nearly zero energy’ buildings (nZEB). Belgium was first to set a definition for a ‘net zero energy house’ (NZEB) in 2009. Every year the definition is revised for consistency with shortcomings and emerging issues. The Belgian definition raised many questions regarding (1) the net balance, (2) the application and calculation method (3) the indoor air quality and comfort, (4) energy use included in the balance, (5) the type of buildings, (6) the accepted renewable energy supply options, (7) the quality assurance and monitoring and (8) energy storage and the connection to the energy infrastructure. Therefore, the paper presents a review on the current Belgian definition and its market status in comparison with the international context. The aim of the paper is to review current definition discussions and pave the way to a more consistent definition.
Principles for Nearly Zero Energy Building in Belgium
Subtask A: Definitions and Implications
June 2012 - Posted: 2012-07-04
The recast of the European Performance of Buildings Directive (EPBD) requires all new buildings to
be “nearly zero energy’ buildings (nZEB) by 2020, including existing buildings undergoing major
renovations. Belgium was first to set a definition for a ‘net zero energy house’ (NZEB) in 2009. Every
year the definition is revised for consistency with shortcomings and emerging issues. However, to
reach the nZEB objective many questions are raised in the Belgian context. Many uncertainties exist
among local governments and municipalities to achieve that objective. Therefore, the paper presents
a review on the current Belgian definition and its market status in comparison with the international
context. The paper builds on existing experience with the implementation of the EPB calculation
method and the Passive House initiative. The aim of the paper is to review current definition
discussions and pave the way to a more consistent definition. Finally, four principles are suggested to
reach the nZEB objectives in Belgium.
Net zero energy buildings: A consistent definition framework
February 2012 - PDF 0.68MB - Posted: 2012-02-21
By: Igor Sartori, Assunta Napolitano, Karsten Voss
The term Net ZEB, Net Zero Energy Building, indicates a building connected to the energy grids. It is recognized that the sole satisfaction of an annual balance is not sufficient to fully characterize Net ZEBs and the interaction between buildings and energy grids need to be addressed. It is also recognized that different definitions are possible, in accordance with a country’s political targets and specific conditions. This paper presents a consistent framework for setting Net ZEB definitions. Evaluation of the criteria in the definition framework and selection of the related options becomes a methodology to set Net ZEB definitions in a systematic way. The balance concept is central in the definition framework and two major types of balance are identified, namely the import/export balance and the load/generation balance. As compromise between the two a simplified monthly net balance is also described. Concerning the temporal energy match, two major characteristics are described to reflect a Net ZEB’s ability to match its own load by on-site generation and to work beneficially with respect to the needs of the local grids. Possible indicators are presented and the concept of grid interaction flexibility is introduced as a desirable target in the building energy design.
Understanding Net Zero Energy Buildings: Evaluation of Load Matching and Grid Interaction Indicators
Proceedings of Building Simulation 2011: 12th Conference of International Building Performance Simulation Association, Sydney, 14-16 November
November 2011 - PDF 1.16MB - Posted: 2012-02-21
By: Jaume Salom, Joakim Widén, José Candanedo, Igor Sartori, Karsten Voss, Anna Marszal
Although several alternative definitions exist, a Net-Zero Energy Building (Net ZEB) can be succinctly described as a grid-connected building that generates as much energy as it uses over a year. The “net-zero” balance is attained by applying energy conservation and efficiency measures and by incorporating renewable energy systems. While based on annual balances, a complete description of a Net ZEB requires examining the system at smaller time-scales. This assessment should address: (a) the relationship between power generation and building loads and (b) the resulting interaction with the power grid. This paper presents and categorizes quantitative indicators
suitable to describe both aspects of the building’s performance. These indicators, named LMGI - Load Matching and Grid Interaction indicators, are easily quantifiable and could complement the output variables of existing building simulation tools. The indicators and examples presented here deal only with electric generation and loads.
Net Zero Energy Building: A Review of Current Definitions and Market Status in Belgium
November 2011 - PDF 0.11MB - Posted: 2012-02-21
By: Erwin Melecnik, Shady Attia, Stefan Van Loon, Irena Kondratenko
The recast of the European Performance of Buildings Directive (EPBD) requires the uptake of a definition of so called ‘nearly zero energy’ buildings (nZEBs). The Belgian Monarch is one of the first countries that set a definition for a ‘net zero energy house’ (NZEB) in 2009. However, this definition is not cast in stone. Every year the definition is revised for consistency with shortcomings and emerging issues. In fact, the Belgian definition raised many questions regarding (1) the net balance, (2) the application and calculation method (3) the indoor air quality and comfort, (4) energy use included in the balance, (5) the type of buildings, (6) the accepted renewable energy supply options, (7) the quality assurance and monitoring and (8) energy storage and the connection to the energy infrastructure. Therefore, the paper presents a review on the current Belgian definition and its market status in comparison with the international context. The aim of the paper is to review the current definition and proposes a more consistent definition.
From Low-Energy to Net Zero-Energy Buildigns: Status and Perspectives
April 2011 - PDF 0.93MB - Posted: 2011-04-29
By: Karsten Voss, Eike Musall, and Markus Lichtmeß
“Net Zero-Energy Building” has become a popular catchphrase to describe the synergy between energy-efficient building and renewable energy utilisation to achieve a balanced energy budget over an annual cycle. Taking into account the energy exchange with a grid overcomes the limitations of energy-autonomous buildings with the need for seasonal energy storage on-site. Although the expression, “Net Zero-Energy Building,” appears in many energy policy documents, a harmonised definition or a standardised balancing method is still lacking. This paper reports on the background and the various effects influencing the energy balance approach. After discussing the national energy code framework in Germany, a harmonised terminology and balancing procedure is proposed. The procedure takes not only the energy balance but also energy efficiency and load matching into account.
Zero Energy Building: A Review of Definitions and Calculation Methodologies
December 2010 - PDF 0.18MB - Posted: 2011-01-19
By: A.J. Marszala, P.Heiselberg, J.S.Bourrelle, E.Musall, K.Voss, I.Sartori, A.Napolitano
The concept of Zero Energy Building (ZEB) has gained wide international attention during last few years and is now seen as the future target for the design of buildings. However, before being fully implemented in the national building codes and international standards, the ZEB concept requires clear and consis- tent definition and a commonly agreed energy calculation methodology. The most important issues that should be given special attention before developing anewZEB definition are: (1) the metric of the balance, (2) the balancing period, (3) the type of energy use included in the balance, (4) the type of energy balance, (5) the accepted renewable energy supply options, (6) the connection to the energy infrastructure and (7) the requirements for the energy efficiency, the indoor climate and in case of gird connected ZEB for the building–grid interaction. This paper focuses on the review of the most of the existing ZEB definitions and the various approaches towards possible ZEB calculation methodologies. It presents and discusses possible answers to the abovementioned issues in order to facilitate the development of a consistent ZEB definition and a robust energy calculation methodology.
Defining nearly zero-energy housing in Belgium and the Netherlands
Subtask A: Definitions and Implications
November 2010 - PDF 0.33MB - Posted: 2012-07-04
Europe expects the housing sector to evolve towards ‘nearly zero-energy’ dwellings. Meanwhile, general terms and research, marketing and legal definitions considering such dwellings have already been introduced. Appraisal of existing definitions
is now needed for further policy development. This paper examines what nearly zero-energy terms can be expected to be adopted in Belgium and the Netherlands. The research method uses an interview method based on innovation diffusion theory. The analysis traces the regional adoption trajectory of relevant definitions and examines the opportunities and barriers for the inclusion of existing definitions in regional energy policy. The analysis shows that—whilst international prominence of the terms ‘net zero energy’ and ‘net zero carbon’, in addition to ‘low energy’ and ‘passive house’, is observed—in Belgium and the Netherlands ‘passive house’ and ‘energy neutral’ are preferred. The research findings indicate
that the adoption of already existing definitions for nearly zero-energy houses will depend on the region and can prove a very complex process with several conflicting issues. Terms should be clearly defined and used at all political and marketing levels. It is recommended to enhance the relative advantage, demonstrability, visibility and compatibility of favoured
definitions by policy initiatives.
Criteria for Definition of Net Zero Energy Buildings
Eurosun 2010 Paper
March 2010 - PDF 0.03MB - Posted: 2010-03-29
By: Igor Sartori, Assunta Napolitano, Anna J. Marszal, Shanti Pless, Paul Torcellini and Karsten Voss
The idea of a Net Zero Energy Building (NZEB) is understood conceptually, as it is understood that the way a NZEB is defined affects significantly the way it is designed in order to achieve the goal. However, little agreement exists on a common definition that is based on scientific analysis. The term is used commercially without a clear understanding and countries are enacting policies and national targets based on the concept without a clear definition in place.
Net Zero Energy Buildings: Calculation Methods and input Variables - An international View
Eurosun 2010 Paper
March 2010 - PDF 0.02MB - Posted: 2010-06-29
By: J. Bourrelle et .al.
The International Energy Agency (IEA), through the Solar Heating and Cooling Programme (SHC) Task 40 and the Energy Conservation in Buildings and Community Systems Programme (ECBCS) Annex 52 , works towards developing a common understanding and setting up the basis for an international definition framework for Net Zero Energy Buildings (NZEBs). The understanding for such buildings and how the NZEB status should be calculated differs in each of the participating country. Within the task activities, the participants surveyed and compared the variables used for calculation and each country’s national calculation methodologies.
Load Matching and Grid Interaction of Net Zero Energy Buildings
Eurosun 2010 Paper
March 2010 - PDF 0.11MB - Posted: 2010-06-29
By: K. Voss et. al.
Net zero energy use. The goal sounds simple and is presented excessively in variations all over the world. Major advantage of the Net Zero Energy Building (Net ZEB) concept is – on the first look – the absence of energy performance indicators such as kWh/m² with the need to set agreed energy limits and reference areas. This simplicity is a major background for the high political and public acceptance of the wording. In general a conventional building might be called Net ZEB as long as the annual energy needs or the associated carbon emissions are balanced by credits from excess energy feed into the grid.
Comfort and Energy Performance Recommendations for Net Zero Energy Buildings
Eurosun 2010 Paper
March 2010 - PDF 0.09MB - Posted: 2010-06-29
By: I. Sartori et. al
Conceptually, a Net Zero Energy Building (Net ZEB) is a building with greatly reduced energy needs that are balanced by an equivalent generation of electricity, or other energy carriers, from renewable sources. So far no common agreement exists on a clear and sound definition of Net ZEB, even though the subject is receiving significant attention in many countries. A major advantage of the Net ZEB approach is claimed to be the absence of energy performance indicators, hence avoiding the need to set internationally agreed limits.
Goal: Zero Energy Building
Exemplary Experience Based on the Solar Estate Solarsiedlung Freiburg am Schlierberg, Germany
December 2009 - PDF 0.32MB - Posted: 2010-02-16
By: Mira Heinze and Prof. Karsten Voss
Zero energy consumption. The goal sounds simple and is presented excessively in variations all over the world. Energy and environmental politics demand zero consumption as a long-term goal, marketing has discovered the concept and first buildings and settlements aiming at balanced energy or emission budgets have been constructed.
Subtask B: Design Process Tools
Assessing Gaps and Needs for Integrating Building Performance Optimization Tools in Net Zero Energy Buildings Design
September 2013 - PDF 0.6MB - Posted: 2013-09-25
By: Shady Attiaab, Mohamed Hamdy, William O’Brien, Salvatore Carlucci
This paper summarizes a study undertaken to reveal potential challenges and opportunities for integrating optimisation tools in Net Zero Energy Buildings (NZEB) Design. The paper reviews current trends in simulation-based Building Performance Optimisation (BPO) and outlines major criteria for optimisation tools selection and evaluation. This is based on analyzing user’s needs for tools capabilities and requirement specifications. The review is carried out by means of a literature review of 165 publications and interviews with 28 optimisation experts. The findings are based on an inter-group comparison between experts. The aim is to assess the gaps and needs for integrating BPO tools in NZEB Design. The findings indicate a breakthrough in using evolutionary algorithms in solving highly constrained envelope, HVAC and renewable optimisation problems. Simple Genetic Algorithm solved many design and operation problems and allowed measuring the improvement in the optimality of a solution against a base case. Evolutionary Algorithms are also easily adapted to enable them to solve a particular optimization problem more effectively. However, existing limitations including model uncertainty, computation time, difficulty of use and steep learning curve. Some future directions anticipated or needed for improvement of current tools are presented.
An Optimization Procedure Based On Thermal Discomfort Minimization To Support The Design Of Comfortable Net Zero Energy Buildings
August 2013 - PDF 1.03MB - Posted: 2013-10-16
By: Salvatore Carlucci and Lorenzo Pagliano
The European standard EN 15251 specifies design criteria for dimensioning of building systems. In detail, it proposes that the adaptive comfort model is used, at first, for dimensioning passive means; but, if indoor operative temperature does not meet the chosen long-term adaptive comfort criterion in the “cooling season”, the design would include a mechanical cooling system. In this case, the reference design criteria are provided accordingly the Fanger comfort model. However, there is a discontinuity by switching from the adaptive to the Fanger model, since the best building variant, according to the former, may not coincide with the optimal according to the latter.
Computational Optimisation For Zero Energy Buildings Design: Interviews Results With Twenty Eight International Experts
August 2013 - PDF 1.04MB - Posted: 2013-10-16
By: Shady Attia, Mohamed Hamdy, William O’Brien, Salvatore Carlucci
This paper summarizes a study that was undertaken to reveal potential challenges and opportunities for integrating optimisation tools in Net/Nearly Zero Energy Buildings (NZEB) Design. The paper reviews current trends in simulation-based Building Performance Optimisation (BPO) and outlines major criteria for optimisation tools selection and evaluation. This is based on analyzing users’ needs for tools capabilities and requirement specifications. The review is carried out by means of interviews with 28 optimisation experts. The findings are based on an inter-group comparison between experts. The aim is to assess the gaps and needs for integrating BPO tools in NZEB Design. The findings indicate existing limitations including model uncertainty, computation time, difficulty of implementation and steep learning curve. Future directions anticipated or needed for improvement of current tools are presented.
Tool for Design Decision Making: Zero Energy Residential Buildings in Hot Humid Climate
August 2013 - PDF 1.2MB - Posted: 2013-10-16
By: Shady Attia, Elisabeth Gratia, Andre De Herde, Jan L. M., Hensen
Informed decision-making is the basis for the design of Net Zero Energy Buildings (NZEBs). This paper investigates the use of building performance simulation tools as a method of informing the design decision of NZEBs. The aim of this study was to develop a design decision making tool, ZEBO, for zero energy residential buildings in hot climates and to evaluate the effect of a simulation-based decision aid, on informed decision-making using sensitivity analysis. An assessment of the role of the BPS tools used in informing the decision-making was ascertained through cases studies, usability testing and several self-reported metrics. The paper provides results that shed light on the effectiveness of sensitivity analysis as an approach for informing the design decisions of NZEBs.
A Control-Oriented Simplified Building Modelling Strategy
August 2013 - PDF 1.3MB - Posted: 2013-10-16
By: Jose A. Candanedo, Vahid R. Dehkordi and Phylroy Lopez
This paper discusses the development of control-oriented simplified modelling strategy (COSMOS) for model-base predictive control (MPC) in buildings. In MPC, a model of the system is used along with forecast information for optimal planning. A model that is as simple as possible --but accurate enough for the purpose at hand -- facilitates the implementation of a MPC strategy. This paper discusses desirable features of models intended for the specific needs of advanced control applications. A path for the creation of such models is presented, based on low-order resistance-capacitance (RC) thermal networks and their equivalent state-space formulation; such an approach provides physical insight while facilitating the treatment of the problem. The model parameters are found by applying an optimization to match the output of a building simulation model. Results include an assessment of the uncertainty of the model outputs.
Time-Lapse Photography and Image Recognition to Monitor Occupant-Controlled Shade Patterns: Analysis And Results
August 2013 - PDF 1.13MB - Posted: 2013-10-16
By: K. Kapsis, W. O’Brien, A.K. Athienitis
This paper presents a high-level overview of a methodology for analysing windows shade use is existing buildings. Time-lapse photography is paired with a robust image recognition algorithm to facilitate assessment of shade use and identify any possible trends. The methodology applied on a high-rise building consisting of multiple open plan offices. The analysis showed that the mean shade occlusion and the shade movement rate depend on facade orientation, with the near-south facade having the highest values and the near-north facade having the lowest ones. An average shade use rate of 0.5/day was observed, with the 72% of the shades never adjusted, throughout the period of observation.
Design of Nearly Zero Energy Buildings Coupled With an Earth to Air Heat Exchanger in Mediterranean Climate: Development of an Analytic Model and Validation Against a Monitored Case Study
August 2013 - PDF 0.92MB - Posted: 2013-10-16
By: Lorenzo Pagliano, Paolo Zangheri
At the Passivhaus of Cherasco, located in Pianura Padana (Italy), an earth to air heat exchanger (EAHE) and natural night ventilation (in summer) are used to deliver comfort conditions with very low energy consumption. One year and a half of continuous measurements have been carried out in order to evaluate the energy and comfort performances of this building, which combines the Passivhaus concept with local architectural solutions. We present an analysis of the system constituted by building envelope and EAHE. Monitored data (with a particular focus on cooling potential) were evaluated with the use of established indicators and compared with simulations performed by coupling dynamic simulation software (EnergyPlus) and an analytic model for the EAHE. Based on this analysis a simplified steady-periodic model is developed to provide an estimate of the behaviour of the coupled system building envelope (including night ventilation) and EAHE from the point of view of energy and comfort, over a period of few weeks. The model is validated towards monitored data and shows a good agreement in terms of temperature profile, with a slight phase discrepancy, as expected based on the simplifying assumptions about thermal capacity effects.
Strategies for Reducing Peak Demand in Net-Zero Energy Solar Homes
August 2011 - PDF 0.62MB - Posted: 2012-02-21
By: José A. Candanedo and Andreas K. Athienitis
This paper investigates strategies to reduce peak loads in net-zero energy solar homes through the coordination of different design and operation strategies. The concept of net-zero energy homes, roughly defined as grid-tied houses that supply their energy needs with renewable energy sources over a period of interest, has gained in popularity in recent year. In spite of the clear advantages of this design approach, it is necessary to address the issue of peak loads and their impact on utility grids. Even if the net-zero energy goal is achieved during the period of assessment (e.g., one year), significant imbalances may be observed at smaller time scales. For instance, in northern latitudes, the generation of PV panels typically exceeds the energy use of the house during the summer months, while in winter the energy use of the house is larger than the generation of the PV system. Fluctuations of the ratio generation/use are also registered during the daily cycle. If a net zero energy house draws energy from the utility grid during peak periods, its impact on the grid will be similar to that of a conventional home, with the subsequent need for increased generation and transmission capacity.
Optimization of Net-Zero Energy Solar Communities: Effect of Uncertainty Due to Occupant Factors
August 2011 - PDF 0.38MB - Posted: 2012-02-21
By: Scott Bucking, Andreas Athienitis, Radu Zmeureanu
This paper applies an energy optimization methodology to evaluate the impact of occupant factors on the net-energy consumption or generation of a community of net-zero energy or near net-zero energy homes located in Montreal, Quebec. The building simulation software EnergyPlus was used for energy simulations and Canadian national statistics were used to model occupant behaviour. Results showed that diversifying building designs can decrease the impact of variability of occupant behaviour and reduce peak loads.
Energy Performance, Comfort and Lessons Learned From a Near Net-Zero Energy Solar House
June 2011 - PDF 1.63MB - Posted: 2012-02-21
By: Matt Doiron, P.Eng., William O’Brien, Andreas Athienitis, Ph.D., P.Eng.
This paper examines the performance of a Canadian near net-zero energy solar house known as ÉcoTerra located near Montreal. The total energy consumption and energy end-use breakdown are presented and several findings from the energy analysis are discussed such as the importance of occupant behavior, occupant comfort and the improvements that could lead to achieving full net-zero energy performance . It was demonstrated that large reductions in energy consumption can be achieved with little effect on comfort. Occupants affect the loads significantly and need to be educated and given specific feedback about their energy use patterns in order to help them adjust their behavior for energy efficiency. Although already far below the typical home in energy consumption (about 90%), this paper shows how ÉcoTerra could consume even less energy and how similar houses could be designed or upgraded to achieve net zero energy.
Design Optimisation Methodologies for a Near Net Zero Energy Demonstration Home
Eurosun 2010 Paper
March 2010 - PDF 0.21MB - Posted: 2010-03-29
By: S. Bucking et. al.
This paper applies an energy optimization methodology to identify improvements to an existing near net-zero energy house located south of Montreal, Canada. As many of the design performance parameters are strongly coupled, a hybrid evolutionary algorithm was used to ensure full solution space exploration, and harmonized parameter variation. This paper presents a set of ‘lessons learned’ to be applied to the design of future net-zero energy homes.
Applying A Design Methodology for a Net Zero Energy House to Evaluate Design Processes and Tools
Eurosun 2010 Paper
March 2010 - PDF 0.05MB - Posted: 2010-06-29
By: W. O’Brien, et. al.
EcoTerra is a house near Montreal that combines passive solar features (large windows and integrated thermal mass) and active solar features (a BIPV/T roof and thermal storage system) to achieve near net-zero energy (NZE) . This paper presents and applies a methodology for redesigning the house to achieve net-zero energy. The objectives are: 1) to demonstrate the use of tools of varying degrees of model resolution and 2) address any weaknesses and new useful features in existing tools.
Solar 2002: A Belgian Pilot Project for Zero Energy Buildings
Eurosun 2010 Paper
March 2010 - PDF 0.37MB - Posted: 2010-06-29
This paper describes the “Solar 2002” building in Berlaar (Belgium) that was constructed by the Flemish non-profit organization Mondo vzw. The aim of this retrofit of an existing single family dwelling was the creation of an example project, demonstrating the potential of solar energy for the energy needs of buildings in a temperate, rather cloudy climate. This has led to a “Net-Zero Energy” building, that finally supplies more energy to the grid, then it consumes on an annual basis. This paper focuses on the energy-aspect for the building in use. Technical details of the building and the employed renewable energy technologies are given.
Design, Optimization, and Modeling Issues of Net-Zero Energy Solar Buildings
Eurosun 2010 Paper
March 2010 - PDF 0.21MB - Posted: 2010-06-29
By: R. Klein et. al.
The design of net-zero energy solar buildings (NZESBs) presents a challenge because there is no established design strategy to systematically reach this goal and many of the available tools have limited applicability for such advanced buildings. This paper reviews current design practice and tools for designing NZESBs through a literature review and a survey. It also summarizes the results of some redesign and optimization case studies of existing NZESBs that Subtask B of the IEA SHC Task 40/ECBCS Annex 52 is performing. The outcome of this study identifies effective strategies for the use of design and optimization tools in establishing near optimal NZESB designs.
Subtask C: Advanced Building Design, Technologies and Engineering
ZEMCH 2012 International Conference e-Proceedings
July 2013 - EXE 92.89MB - Posted: 2013-07-05
Editor: Masa Noguchi
Publisher: ZEMCH Network
The ZEMCH 2012 International Conference was a first attempt to establish an intellectual forum of interactive discussion on design, production and marketing issues surrounding the delivery of low to zero energy / CO2 emission mass-customizable home and communities being built in developed and developing countries. This download is the e-proceedings. You need to download the .exe file and then run it on your computer to view the complete proceedings. The file is 92MB in size.
Photovoltaics and Zero Energy Buildings: A New Opportunity and Challenge for Design
October 2012 - PDF 1.21MB - Posted: 2013-02-14
By: Alessandra Scognamiglio and Harald N. Røstvik
Starting from the end of 2020, all new buildings will have to be Nearly Zero Energy Buildings (Nearly ZEBs—ED 2010/31/EU recast). This new ‘energy paradigm’ might be a revolution for architecture and for Photovoltaics (PV) too, but there are both cultural and technical obstacles to overcome. There is a need to re-think the way buildings are designed (integrating renewables for being ZE). There is a need to re-think the way PV is designed in buildings. PV will be gaining an increasing relevance in the ZEBs design, thanks to its features and potentialities (suitability for any kind of energy demand of the building, easiness of building integration, cost). In a ZEB scenario, PV is very suitable for generating energy, ‘on site’ and ‘at site’; this enlarges the perspective of use of PV from the architectural scale to a wider scale, including the space close to the building or even to the urban and landscape scale. In such a new context, the existing research on the relationships between PV and architecture, focusing mainly on the way the PV components are used in relation to the envelope (Building-integrated PV/Building-added (Attached) PV), is no longer sufficient. The authors envision possible formal results, opportunities and challenges, for the use of PV in ZEBs, as well as new research issues for the future relationships between PV and ZEBs from the architecture and landscape design point of view. Copyright © 2012 John Wiley & Sons, Ltd.
Towards Net Zero Energy Buildings in Hot Climates: Part 1, New Tools and Methods
November 2011 - PDF 0.87MB - Posted: 2012-02-21
By: François GARDE, PhD, PE, Mathieu David, PhD, PE, Aurélie Lenoir, Eric Ottenwelter, PE
The paper presents the results of a French National research project on Net zero energy design that just ended in December 2009. The project named « ENERPOS »has focused on the development of new methods and tools for the design of Net Zero Energy Buildings in hot climates. Three French university research laboratories and two HVAC practices have been involved in the project. The initial objectives of the ENERPOS project were: to develop new methods and tools for the design of net zero energy buildings in hot/tropical climates; to point out that the factor 3 is easy to meet. The energy index must be below 55 kWhe/m².year (net floor area); to gather the world of research and the professional sector for improving the use of new simulation tools; to do a transfer of knowledge from research to the professional fields once the proposed method validated. The methods and tools have been applied to the design of the first zero energy building of the French overseas departments located in La Reunion. The design and the construction of the building has perfectly matched with the realization of the ENERPOS project. The completion was in October 2008, just one year before the end of the ENERPOS project.
Towards Net Zero Energy Buildings in Hot Climate, Part 2: Experimental Feedback
November 2011 - PDF 0.99MB - Posted: 2012-02-21
By: Aurélie Lenoir, Françoise Thellier, Phd PE, François Garde, Phd PE
The paper deals with the feedback of the measurements conducted in the first zero energy building “EnerPos” constructed in the French tropical Island of La Reunion. The building was designed to operate as long as possible by using passive techniques (cross natural ventilation, day-lighting). The purpose was to reach an annual energy ratio below 55kWh/m² (which is three times below the mean ratio of standard buildings in La Reunion) by avoiding energy consuming active systems such as air-conditioning and artificial lighting.
Formulating a Building Climate Classification Method
November 2011 - PDF 0.52MB - Posted: 2012-02-21
By: Shaan Cory, Victoria University of Wellington, Wellington, New Zealand
When country champions participating in the International Energy Agency Task 40 project on Net Zero Energy Buildings were asked to classify their countries climate, six of the participating countries categorised the residential and non-residential buildings, placed in the same location, into different climate zones. This indicated that a climate zoning for buildings that is based purely on the external climate conditions is not sufficient. This paper proposes an adjustment of the traditional approach to climate classification for buildings by utilising thermal simulation to formulate a building climate classification. This produces a climate indicator that is founded on the locations external conditions and the reference buildings thermal performance.
Users' Behavior and Energy Performances of Net Zero Energy Buildings
June 2011 - PDF 1.18MB - Posted: 2012-02-21
By: Aurélie Lenoir, Shaan Cory, Michael Donn and François Garde
This paper proposes to study the role and the user in the operation of the building and its impact on energy performance of buildings. Some comparisons of the energy consumption and production of the buildings were calculated during the design stage are made against the measured data of the consumption and production of the buildings when they are being utilized. It indicated that the differences between the design calculations and the measurements can be up to 50%. The method used in this study is to restart the process of calculation for the energy balance that was adopted during the design phase and to establish the right hypothesis on the schedules, utilization of appliances, and comfort level of the building that lead to a good evaluation of the energy consumed in the actual buildings operation. This feedback on the tools used by the design offices will allow making improvements in these tools.
Environmental design and performance of the ENERPOS building, Reunion island, France
June 2011 - PDF 0.59MB - Posted: 2012-02-21
By: Maximilien FRANCO, George BAIRD, François GARDE, Aurélie LENOIR
Located in the French tropical Island of La Reunion in the Indian Ocean, the 681 m2
NFA ENERPOS Building was inaugurated in January 2009. The building is located on the Saint Pierre Campus of the University of Reunion Island and was designed from the outset to be a net zero energy project with mixed-mode air conditioning systems in some areas. This paper reports the results of a recent user survey of the staff and students who use the building, and relates the users' perceptions to some of the environmental control systems installed. Indications are that the users have been able to achieve thermally comfortable conditions for much of the year without recourse to the air conditioning systems. However, there is still the need for more readily available information on how to get the best from the windows and the ceiling fan systems for the ever-changing cohorts of students, and staff who may only use the classrooms intermittently. For the more permanent staff group, preliminary indications are of improved health and productivity by comparison with their experience of other buildings.
Calibrating the Impact of a Photovoltaic Thermal Mechanical Ventilation Heat Recovery System on the Delivery of Net Zero-energy Housing in Scotland
June 2011 - PDF 0.15MB - Posted: 2012-02-21
By: Dr. Masa Noguchi, Dr. Yoshiki Higuchi, Prof. Mitsuhiro Udagawa, Prof. Jun-Tae Kim, Billy Kirkwood
This study was conducted with the aim to assess the potential performance of a photovoltaic thermal mechanical ventilation heat recovery (PV/T MVHR) system. The device is currently considered for the application to the Z-en house project undertaken by Scottish homebuilder, ROBERTRYAN Homes, in collaboration with ZEMCH Network academic partners. The house’s whole energy demand was calibrated based on the UK government’s standard assessment procedure for energy rating of dwellings, known as SAP, while the PV/T performance was estimated using an ‘EESLISM’ energy and environmental design simulation tool developed by Kogakuin University. This study concluded that PV generates heat, which makes the fresh air running under the PV roof 10-15°C warmer than the outside temperature even during the Scottish winter and this warm air extracted from roof integrated PV modules can be used to drastically reduce the domestic space-heating demand. Thus, the building integrated PV/T MVHR system was considered as one of the effective means to facilitate the net zero-energy operation of housing in cool and cold climates.
Net Zero Energy Solar Buildings: An Overview and Analysis on Worldwide Building Projects
Eurosun 2010 Paper
March 2010 - PDF 0.38MB - Posted: 2010-03-29
By: E. Musall et. al.
Given the global challenges related to climate change and resource shortages, much more is required than sustainability or increases in energy efficiency in buildings. The zero energy building is no more a vision what is shown by many built examples. Although these buildings are named by different terms and are poorly understood, several countries have adopted this vision as a long-term goal of their building energy policies.
Net Zero Energy Buildings in France, From Design Studies to Energy Monitoring - A State of the Art Review
Eurosun 2010 Paper
March 2010 - PDF 0.14MB - Posted: 2010-03-29
By: A. Lenoir et. al.
In 2020, the French energy policy plans that every new building will be positive energy. It is then essential to develop new methods for the design of such buildings. In addition, energy monitoring should be studied on existing positive or near zero energy buildings to ensure that they really respect this characteristic but also to estimate the impact of certain improvements made on the building design to the energy consumption.
The Road Towards “Zero Energy” in Buildings: Lessons Learned from The Solar XXI Building in Portugal
Eurosun 2010 Paper
March 2010 - PDF 0.06MB - Posted: 2010-06-29
By: L. Aelenei et. al.
On April 23, 2009, Industry, Transport, Research and Energy (ITRE) Committee of the European Parliament voted favorable for the amendment of the Energy Performance of Buildings Directive (EPBD) so that all new buildings to become Net-Zero Energy Buildings (NZEB) by 31 December 2018. With regard of existing buildings, the Member States were called to set minimum percentages of buildings that should be zero energy by 2015.
BOLIG+ - an Energy Neutral Multifamily Building
Eurosun 2010 Paper
March 2010 - PDF 0.12MB - Posted: 2010-06-29
By: K. Wittchen et al.
BOLIG+ is a Danish concept for energy neutral houses based on five dogmas: 1) energy neutral incl. household energy, 2) intelligent and user-friendly, 3) flexible in daily use and over time, 4) good and healthy indoor climate and 5) high architectural quality and adaption to local context.