Choices have to be made at the national level. In several countries this is or will be done, at least for the time being, in a practical way, by copying the relevant parts of EN ISO 13790 as national standard, adding further specifications. (See CENSE Information Paper P90 on the practical use of CEN standards which can also be downloaded from the BUILD UP Portal).
Question submitted by: Dick van Dijk (TNO, The Netherlands)
Anwered by: Dick van Dijk (TNO, The Netherlands)
Date: 21/10/2008
If an ISO (International Organization for Standardization) standard is also an EN ISO standard, then it is a European standard just like any other EN (European) standard. As illustrated in several CENSE Information Papers, e.g. P92 or P94, a CEN standard to support the EPBD is one of a series of standards, which are mutually related and serve particular European (EPBD) needs; in particular: which are meant to be applied in the context of national building regulations. If, for this purpose, such an EN ISO standard needs to make a reference to another EN standard, then one may find in the standard a distinction between references to EN standards for use within the CEN area and references to ISO or national standards for use outside Europe.
In EN ISO 13790, for instance, this was solved by concentrating all references to other standards in one normative annex (Annex A), which provides for the "CEN area": references to CEN (EN or EN ISO) standards and for "elsewhere": references to ISO standards or, in absence of ISO standards, to national standards (see CENSE Info Paper P92 which can also be downloaded from the BUILD UP Portal).
Question submitted by: Dick van Dijk (TNO, The Netherlands)
Anwered by: Dick van Dijk, TNO (The Netherlands) and Brian Anderson, BRE (UK)
Date: 2009/02/19
Yes, but some of the required input data may not be available at reasonable costs. For those cases default values may be provided at national level, e.g. as function of type and age of construction.
Question submitted by: Dick van Dijk (TNO, The Netherlands)
Anwered by: Dick van Dijk, TNO (The Netherlands) and Brian Anderson, BRE (UK)
Date: 2009/02/19
Heat is lost from a building or building part by transmission or ventilation, as a result of a positive temperature difference between the indoor and outdoor (or other) environment. However, if the indoor temperature of the considered building or building part is lower than the temperature of the other environment (outdoor environment or another building part), the heat loss becomes negative. Therefore the more neutral term “heat transfer” was introduced from the 2007 versions of the EPBD related standards on. The downside of this is, that now it must be explicitly stated which direction has the positive sign. By definition, if the heat flows from the considered building or building part to the other environment, it has a positive sign.
NOTE: a negative heat loss should not be confused with “heat gain”. The term heat gain (see e.g. EN ISO 13790, energy use for heating and cooling) is used for solar and internal gains which are not a function of the indoor-outdoor temperature difference: if the indoor temperature rises, e.g. due to excess gains, the heat transfer by transmission and ventilation will automatically rise proportionally, but the solar and internal heat gains remain the same (compare the electric equivalent: a current through a resistor versus a current source).
Question submitted by: Dick van Dijk (TNO, The Netherlands)
Anwered by: Dick van Dijk, TNO (The Netherlands) and Brian Anderson, BRE (UK)
Date: 2009/02/19
National documents define under which conditions the two methods are to be applied. The choice of method depends on several aspects. First the purpose of the assessment should be considered, as it influences the level of detail required. The type and complexity of the building and its technical system are also relevant parameters. In general, the holistic approach is applied for complex systems and when a high level of detail is required.
More information: CENSE Information Paper P095 which can also be downloaded from the BUILD UP Portal.
Question submitted by: Dick van Dijk (TNO, The Netherlands)
Anwered by: Anna Staudt and Hans Erhorn, Fraunhofer Institute of Building Physics (Germany)
Date: 2008/02/04
No, it will not lead to the same energy performance rating in each Member State.
Regional differences in climate, building tradition and user behaviour in Europe will have an impact on the input data and consequently on the energy performance.
The standards developed to support the practical implementation of the EPBD have to be flexible enough to accommodate these differences, both in the (national) choice between different options provided in the CEN standards, and in the (national) choice of input data and boundary conditions. See also the question on the status of the EPBD related CEN standards.
Author: Dick van DIJK (TNO)
Date: 14/04/06
All CEN standards (EN or EN-ISO) and draft standards (prEN or prEN-DIS) can be ordered from the National Standards Body organisation (NSB) (see www.cen.eu).
All EPBD CEN standards were published in 2007 or 2008, as EN or EN-ISO standards.
The total set contains 2000 pages. As usual, EN’s are published in English and, by choice of DIN and AFNOR, also published in a German or French version. It is up to the other NSB’s to decide if national language versions will be produced, depending on the target group as explained under the question: "Are CEN standards only available in English?".
Author: Dick van DIJK (TNO)
Answered by: Dick van Dijk, TNO and Jaap Hogeling, ISSO (The Netherlands)
Date: 2008/03/10
There is an agreement between CEN and ISO saying that they shall not work on the same Work Items. New work can only be started in CEN if it is not already on the ISO program and vice versa.
CEN-Technical Committees are encouraged to seek contact with related ISO-Technical Committees to agree on possible parallel voting. This means that the European standard (EN) may become a combined CEN-ISO standard (ISO-EN) if accepted by ISO.
Existing ENs will by preference be maintained by related ISO-Technical Committees. Only when related ISO-Technical Committees are not interested or not giving it enough priority, will the CEN-TC continue the normal 5 years maintenance schedule or faster if needed.
Author: Dick van DIJK (TNO)
Date: 14/04/06
There is an agreement between CEN and the national standards bodies (NSBs) that CEN standardisation work shall be considered before starting national standardisation work. If CEN work is already started, this line shall be followed and national work should not be done. It is called a "Stand still". After the ENs are published, existing and possibly conflicting national standards shall be withdrawn within a certain time frame. If national legislation is referring to these national standards, the NSB can get some years to repair this. A three to five years period is considered as the maximum deviation period in which national standards shall be withdrawn.
Note, however, that in some Member States the building regulations do not always refer to national standards, but e.g. have (part of) the assessment procedures included in the regulations. In the case of the Construction Products Directive, the European Commission issues mandates to CEN to make use of CEN standards mandatory for all Member States. The EPBD allows a national/regional differentiation. See also the question on the status of the EPBD related CEN standards.
Author: Dick van DIJK (TNO)
Date: 14/04/06
CEN standards (ENs) or draft CEN standards (prENs) and combined EN-ISO standards are officially published by CEN in Brussels but can only be obtained from the so called National Standards Bodies (NSBs). The CEN website (www.cenorm.be) provides the contacts and also has a search engine to see which standard activities are in progress and which existing and draft standards are available.
Author: Dick van DIJK (TNO)
Date: 14/04/06
CEN is the European Association of national standardisation institutes, the so called National Standards Bodies (NSB’s). These NSB’s are responsible for the contact with the interested market parties and experts preparing the CEN standards in the same way they do when preparing national standards. Members of CEN-Technical Committees (CEN-TC’s) are nominated by the NSB’s. The TC’s decide on the scope and content of a standard. The actual work is done in smaller CEN-TC-Working Groups whose expert members are nominated by NSB’s. In most countries the NSB organises a national mirror group to monitor and support the work of a CEN-TC. This was also done in the EPBD program of CEN. Because in this case the work covers 5 CEN-TC’s, some NSB’s organised a special mirror group to follow the work on the total EPBD CEN program.
Members who participate to CEN-TC-WG’s are involved in the details of the standard development. They should contribute themselves, as expert, and be motivated to find the right expertise in their own network.
Once a draft standard is approved by the responsible CEN-TC, it goes out as draft standard (“prEN”) for Public Enquiry. The comments are prepared via the NSB’s. The working group prepares the replies to the comments and prepares a new draft standard which, once approved again by the CEN-TC goes out as final draft for Final Vote. The time between publishing the prEN and publishing the final standard is usually between 21 and 30 months.
Question submitted by: Dick van Dijk (TNO, The Netherlands)
Anwered by: Dick van Dijk, TNO and Jaap Hogeling, ISSO (The Netherlands)
Date: 10/03/2008
In the framework of EPB regulations, an innovative system/technology is defined as a system/technology:
· that in most cases gives a better EPB performance than the common systems/technologies and,
· whose performance cannot be assessed by the standard EPB calculation procedure.
According to the definition mentioned here above, a glazing unit with a very low thermal transmittance (e.g. U-value = 0.3 W/m²K) is not an "innovative technology" if the procedure in the EPB regulation is based on EN 673, because this standard allows the calculation of such U-value – independently of the fact that this glazing can be very innovative from a technical point of view. On the other hand, an electrochromic glazing is an innovative technology if the EPB method foresees no procedure for handling the fact that the properties of this glazing vary with time. This will probably be the case because there is currently no CEN standard to estimate the energy performances of such glazing on an annual basis.
It is important to note that, according to the above definition, a technology can be considered as innovative in one Member State and not in another. For instance, ventilation systems based on humidity control are integrated in the French basis procedure of EPB regulation; they are therefore not considered in France as innovative systems whereas they will be considered as such in most of the other European countries.
More information can be found in the final report of the SAVE ENPER project (see: www.buildingsplatform.eu/cms/index.php or www.enper.org) which will be made available by the SAVE ASIEPI project, started in October 2007 (www.asiepi.eu – coming soon).
Author: Nicolas Heijmans (BBRI)
Date: 14/01/08
There are several reasons why there is not just one CEN standard covering all EPBD aspects. The two main reasons are:
1. The CEN standards cover different types, with different application areas and different target groups, ranging from building designers and inspectors to specific specialists on building physics or systems (lighting, ventilation, cooling, heating, hot water, ..).
2. CEN didn't start this work from scratch. The short timescale and pre-existing drafts (from 5 CEN Technical Committees, each covering a specific field of expertise) have resulted in more fragmentation than if started from scratch. On the other hand, starting from scratch would undeniably have taken much more time and discussion. A guidance document (CEN/TR15615, "Umbrella Document") has been produced on the application of the standards. Moreover, it is expected that, over time the standards will converge into a more unified set.
More information on this subject is given in the Information Papers on CEN standards to support the EPBD. These can be downloaded from the BUILD UP Portal.
Submitted by: Dick van Dijk (TNO, The Netherlands)
Anwered by: Dick van Dijk, TNO (The Netherlands)
Date: 29/04/2009
We expect a further harmonization in the near future. In particular when feedback from the Member States and other target groups has lead to recommendations for improvement of the CEN standards and when these recommendations have been implemented in updated versions of the standards in a few years from now.
The IEE CENSE project (www.iee-cense.eu) may play an important role in identifying and removing the barriers and to promote examples of good practice.
Question submitted by: Dick van Dijk (TNO, The Netherlands)
Anwered by: Dick van Dijk (TNO, The Netherlands)
Date: 29/04/2009
Today most companies (consultants, manufacturers and contractors) work internationally. From their point of view it is preferable to have internationally accepted calculation methods and input data for the energy efficiency of buildings and building systems.
European standards should therefore form the basis of any revision of national building codes. The IEE CENSE project (www.iee-cense.eu) will interact with all partners (building code writers, consultants, manufacturers, educational institutions, etc.).
The point is to establish a two-way communication:
- CENSE will provide information about the “European Method” and explain the background and use of the standards.
- CENSE will gather information on any obstacles that are encountered and provide examples of good practice for use when applying the standards, in dialogue with the Member States and other stakeholders and will provide feedback to CEN for a any revision of the standards.
So will the future be one harmonized set of CEN procedures to assess and express the energy performance of buildings?
That would be ideal from the point of view of harmonization.
However, we still have to see to what extent regional differences in Europe require differentiation of input data and boundary conditions.
This has to do with differing climates, building traditions (types of new and existing buildings, types of skill) and the economic and social climate (user behaviour, availability of products and skills), legal settings and quality assurance. It may also have to do with related national or regional requirements.To name a few:
- indoor air quality (e.g. which affects the input data for ventilation rates),
- summertime comfort (e.g. which affects the input data for temperature set points),
- usability of indoor spaces (e.g. which affects the classification of an attic as a storage space or as a study or bedroom).
It will be very interesting and important to learn to what extent such differentiation will constitute an obstacle for trans-border transparency, in particular for the comparison between Member States of the energy performance of buildings.
Question submitted by: Dick van Dijk (TNO, The Netherlands)
Anwered by: Dick van Dijk (TNO, The Netherlands)
Date: 29/04/2009
To support the open EU market, more and more standards have been prepared as ENӳ. For building products this is even a requirement based on EU mandates to CEN according to the EU-CPD (Construction Product Directive). To stimulate an open EU market, construction products shall only be specified according to mandatory, socalled ԨarmonisedԠEN (or EN-ISO) standards.
The EPBD stimulates EN standards for the energy calculation procedures for buildings and their systems, and all related performance prescriptive standards needed to specify buildings and systems in relation to the Energy Performance of Buildings Directive. The European Commission gave a mandate to CEN in order to speed up the development of standards needed for the EPBD implementation.
CEN didnӴ start this work from scratch. Already existing CEN Technical Committees have been quite active during the last 15 years preparing international standards in this field. These TCӳ have been involved in developing the CEN program to support the implementation of the EPBD.
The process was overseen by CEN/BT WG 173, Energy performance of buildings project group (currently: CEN/BT TC 371). Itӳ task was to coordinate the work and to ensure that standards prepared in different committees interface with each other in a suitable way.
The EU Mandate to CEN:
The European Commission decided after consultation of the Member States experts, interest groups and CEN, that there was an urgent need for standards to support the EPBD. The aim was to offer within a short period (2004-2006) a clear and consistent set of standards as basis for the national procedures in the Member States. In particular the Member States with a very limited experience in the field of the EPBD could benefit from this.
On the long term, harmonisation of the standards will also be attractive for all Member States. The maintenance and further development costs will be lower compared with the situation where all NSBӳ have to do this on their own. In addition, there is great advantage in having harmonised standards throughout Europe. The widescale implementation of new technical solutions, equipment and systems will become easier if the performance is calculated in a similar way. This means that the industry may have a bigger market throughout Europe which may also benefit their opportunities on the world market.
The development of CEN standards may lead to CEN-ISO standards. The ISO standards are widely accepted and may even increase the market opportunities of the European industry.
Regional differences in climate, building tradition, legal settings, quality assurance and user behaviour in Europe will have impact on the input data and consequently on the energy performance. These differences will also lead to different choices when it comes to finding the optimum balance between accuracy and simplicity. The standards developed under the EPBD have to be flexible enough to accommodate these differences.
Question submitted by: Dick van Dijk (TNO, The Netherlands)
Anwered by: Dick van Dijk, TNO (The Netherlands)
Date: 29/04/2009
The developed standards reflect the requirements of the EPBD as given in the different articles and the annex. The procedures as given in the standards meet the essential requirements as set out by the EPBD.
Note that the EPBD is an example of the application of the principles of subsidiarity and proportionality: general principles are established at Community level, but the detailed implementation are left to Member States, thus allowing each Member State to choose the regime which corresponds best to its particular situation.
Question submitted by: Dick van Dijk (TNO, The Netherlands)
Anwered by: Dick van Dijk, TNO (The Netherlands)
Date: 29/04/2009
The building physics standards, e.g. describing the calculation of heat transfer by transmission and ventilation, load and summer temperature, solar transmittance and the calculation of the energy need for heating and cooling of the building.
In the second group there are standards on the description and properties (classification) of ventilation systems plus cooling and air conditioning systems.
The third group is focussing on the description of space heating and domestic hot water systems:
- The generation efficiency.
- The emission efficiency.
- Domestic hot water systems.
- Low temperature heating and cooling systems integrated in building elements (embedded systems).
A series of supporting standards on:
- Lighting systems for buildings (including the effect of daylight)
- Controls and automation for building services
- Classification of the indoor environment
- Financial economic evaluation of sustainable energy applications.
A set of standards on inspection:
- Boilers and heating systems
- Cooling- and AC systems
- Ventilation systems.
And, last but not least, the two key standards on expressing energy performance and for energy certification of buildings, the overall energy use, primary energy and CO2 emissions, the assessment of energy use and definition of energy performance ratings.
CEN/TR 15615 is not a standard, but a technical report and therefore the definitions (annex C) are not mandatory. However, most of the definitions are adopted also in the European standard EN 15603, which is one of the key standards in the set of standards to support the EPBD. It is intended that the annexes C and D of CEN/TR 15615 will form the basis of a future trilingual standard covering common definitions and symbols for energy calculations. Most Member States are planning to adopt the CEN standards in one way or another within a few years.
Question submitted by: Dick van Dijk (TNO, The Netherlands)
Anwered by: Dick van Dijk, TNO and Jaap Hogeling, ISSO (The Netherlands)
Date: 29/04/2009
It may be that although the National Standard Body produced a national language version, the standard will always be available in English (the official text), in many cases also a French and German version may be available. The French language versions can be ordered from AFNOR and other CEN countries where French is the official language, the same for the German versions, they can be ordered from DIN, ON, etc..
Question submitted by: Dick van Dijk (TNO, The Netherlands)
Anwered by: Dick van Dijk, TNO (The Netherlands)
Date: 29/04/2009
For instance: in EN ISO 13789 the subscripts for transmission and ventilation are T and V in ISO and tr and ve in CEN.
There may be two reasons:
1) because the EN ISO standard was already published before the common symbols were agreed upon in CEN (which was in 2007);
2) because the ISO standard is closely linked to other ISO standards which use different symbols.
Question submitted by: Dick van Dijk (TNO, The Netherlands)
Anwered by: Dick van Dijk, TNO and Jaap Hogeling, ISSO (The Netherlands)
Date: 29/04/2009
In particular in the context of building regulations it is essential that a prescribed method is verifiable and legally secure and that there is consensus on the procedures. Therefore, transparency, robustness and reproducibility are important quality aspects which may hinder the choice of a detailed simulation tool. An overview of advantages and disadvantages of different types of methods, depending on the application, is given in the Buildings Platform Information Paper P026 which can be downloaded from the BUILD UP Portal.
Question submitted by: Dick van Dijk (TNO, The Netherlands)
Anwered by: Dick van Dijk (TNO, The Netherlands)
Date: 29/04/2009
It is a fact that in general most of the preparatory work in the Technical Committees and working groups in CEN is in English. The underlying documentation and the preliminary drafts are in English. When publishing a draft standard (prEN), it is up to DIN (German NSB) and AFNOR (French NSB) to decide if they want to translate and provide CEN with a German or French version. The time schedules allow for 2 months to make this translation available. It is up to the so called National Standards Bodies (NSBs) to decide if other national language versions will be produced. This decision will only be taken if this is required by the users. If the user group is a small expert group of, for example, software developers this seems unlikely. When the standard is referred to in a more general way by a bigger target group, translation should be considered by the NSB.
Question submitted by: Dick van Dijk (TNO, The Netherlands)
Anwered by: Dick van Dijk, TNO and Jaap Hogeling, ISSO (The Netherlands)
Date: 2008.03.10
Question submitted by: Dick van Dijk (TNO, The Netherlands)
Anwered by: Dick van Dijk, TNO and Jaap Hogeling, ISSO (The Netherlands)
Date: 2008/03/10
In general questions on standards could be answered by the National Standard Body helpdesk. They may also refer you to their national experts who have been involved in the preparation of the standard on a national or international level.
For the EPBD standards the BUILD UP website (www.buildup.eu) has a FAQ section and will offer a possibility to raise matters and participate in discussions. Your feed back (e.g. comments and suggestions) is also highly appreciated at the CENSE website (www.iee-cense.eu).
Question submitted by: Dick van Dijk (TNO, The Netherlands)
Anwered by: Dick van Dijk, TNO and Jaap Hogeling, ISSO (The Netherlands)
Date: 29/04/2009
General
The commission supported the development of the CEN standard by giving a mandate to CEN to produce the standards needed to support the implementation of the EPBD. It will be beneficial for Europe if all Member states use these standards as reference. However building regulation is an area where the EU Member States claim their national privilege to formulate the national legislation (also the EPBD adopted the subsidiarity principle in this respect). Although most MS say they use the CEN standards as a basis, as these procedures are in accordance with the EPBD, most of the Member states do not require the direct use of these standards. Standards are worked out in such a way that direct practical use, without supporting national information (national annexes), may be difficult. In some MS part of the content will be found in national publications or regulations, in some other MS using the EPBD standards is always an alternative solution.
Legal arguments
The EPBD has stimulated the more rapid development of CEN standards (ENs) for energy calculation procedures for buildings and their systems, and the related standards that are needed to specify buildings and systems performance in accordance with the Directive. The European Commission issued a mandate to CEN in order to speed up the development of standards needed for implementation of the EPBD.
In the case of the Construction Products Directive (CPD), the European Commission issues mandates to CEN to make use of CEN standards mandatory for all Member States.
In contrast with the CPD, the EPBD allows national and regional differentiation: the European Commission is responsible for generating a common framework (the Directive) in the field of energy efficiency in the building sector. The implementation of the framework and the definition of requirements and procedures is within the exclusive jurisdiction of each Member States (subsidiary principle). The Member States are not bound to use any standard in their regulations. The implemented procedures can be fully covered in the national laws without reference to national or European standards.
Practical arguments
From a practical point of view, within the given short timescale (2004-2007) it was impossible to produce a set of approved and published standards to be implemented in the Member States before the national implementation of the EPBD (which began in 2006).
Consequently, Member States, in the preparation of national legislation, had to refer to either existing or new national procedures.
In addition, at the time of writing the CEN standards, only a limited number of countries had practical experience with procedures for assessing the integrated energy performance of buildings that could be used in national building regulations. Several of the CEN standards reflect this situation by allowing different options to be decided at national level.
Nevertheless, most Member States are planning to adopt the CEN standards in one way or another within a few years.
The IEE CENSE project (www.iee-cense.eu) organizes the information on the CEN standards and the feed back from the Member States.
Question submitted by: Dick van Dijk (TNO, The Netherlands)Anwered by: Dick van Dijk (TNO, The Netherlands)
Date: 29/04/2009
If an ISO (International Organization for Standardization) standard is also an EN ISO standard, then it is a European standard just like any other EN (European) standard. As illustrated in several CENSE Information Papers, e.g. P92 or P94, a CEN standard to support the EPBD is one of a series of standards, which are mutually related and serve particular European (EPBD) needs; in particular: which are meant to be applied in the context of national building regulations. If, for this purpose, such an EN ISO standard needs to make a reference to another EN standard, then one may find in the standard a distinction between references to EN standards for use within the CEN area and references to ISO or national standards for use outside Europe.
In EN ISO 13790, for instance, this was solved by concentrating all references to other standards in one normative annex (Annex A), which provides for the "CEN area": references to CEN (EN or EN ISO) standards and for "elsewhere": references to ISO standards or, in absence of ISO standards, to national standards (see CENSE Info Paper P92 which can also be downloaded from the BUILD UP Portal).
Question submitted by: Dick van Dijk (TNO, The Netherlands)
Anwered by: Dick van Dijk, TNO (The Netherlands) and Brian Anderson, BRE (UK)
Date: 19/02/2008
Yes, but some of the required input data may not be available at reasonable costs. For those cases default values may be provided at national level, e.g. as function of type and age of construction.
Question submitted by: Dick van Dijk (TNO, The Netherlands)
Anwered by: Dick van Dijk, TNO and Brian Anderson, BRE (UK)
Date: 19/02/2009
Heat is lost from a building or building part by transmission or ventilation, as a result of a positive temperature difference between the indoor and outdoor (or other) environment. However, if the indoor temperature of the considered building or building part is lower than the temperature of the other environment (outdoor environment or another building part), the heat loss becomes negative. Therefore the more neutral term “heat transfer” was introduced from the 2007 versions of the EPBD related standards on. The downside of this is, that now it must be explicitly stated which direction has the positive sign. By definition, if the heat flows from the considered building or building part to the other environment, it has a positive sign.
NOTE: a negative heat loss should not be confused with “heat gain”. The term heat gain (see e.g. EN ISO 13790, energy use for heating and cooling) is used for solar and internal gains which are not a function of the indoor-outdoor temperature difference: if the indoor temperature rises, e.g. due to excess gains, the heat transfer by transmission and ventilation will automatically rise proportionally, but the solar and internal heat gains remain the same (compare the electric equivalent: a current through a resistor versus a current source).
Question submitted by: Dick van Dijk (TNO, The Netherlands)
Anwered by: Dick van Dijk, TNO (The Netherlands) and Brian Anderson, BRE (UK)
Date: 19/02/2009
This is explained in detail in annex I.5 of the standard EN ISO 13790. The main difference is that the degree day method contains an implicit assumption about the effect of internal and solar gains on the heat balance (independent of the specific building), while this effect is explicitly taken into account in the monthly method (as a function of the building parameters).
Question submitted by: Dick van Dijk (TNO, The Netherlands)
Anwered by: Dick van Dijk (TNO, The Netherlands)
Date: 21/10/2009
Background information on the origin and rationale of the monthly method can be found in Annex I of the standard EN ISO 13790. It also contains more technical information concerning the content of EN ISO 13790, as well as Annex H of the standard EN ISO 13790 and the bibliography at the conclusion of the standard.
Question submitted by: Dick van Dijk (TNO, The Netherlands)
Anwered by: Dick van Dijk (TNO, The Netherlands)
Date: 21/10/2008
Each method has its own applications: the seasonal method is the simplest, but it is applicable only in climates where seasons are clearly defined, the monthly method is easy to use in buildings without or with small intermittence effects, while the simple hourly method is of more general use, but requires hourly meteorological and use data and, despite the fact that it produces hourly results, it is based on a simplified model with only the monthly results validated. Concerning the pro's and con's of a detailed simulation method, see chapter 8 of CENSE Information Paper P92 which can also be downloaded from the BUILD UP Portal. The choice is strongly related to the (national) application and may depend on the type and complexity of the building.
Question submitted by: Dick van Dijk (TNO, The Netherlands)
Anwered by: Dick van Dijk (TNO, The Netherlands)
Date: 29/04/2009
The monthly method and the simple hourly method were indeed validated by comparison to detailed calculations and to the actual energy use of several buildings (monthly values). The monthly method for heating has been in use since 1990. (See annex H of the standard EN ISO 13790.)
Question submitted by: Dick van Dijk (TNO, The Netherlands)
Anwered by: Dick van Dijk (TNO, The Netherlands)
Date: 21/10/2009
This is possible if not only the overall energy performance (in MJ or kWh), but also the system energy performance is reported separately. The same goes for the local production of renewable energy. EN 15603 describes how this could be done. Given the different lifespan of building elements and building systems separate consideration would be beneficial.
Question submitted by: Dick van Dijk (TNO, The Netherlands)
Anwered by: Dick van Dijk, TNO and Jaap Hogeling, ISSO (The Netherlands)
Date: 10/03/2008
There is a consensus within Europe that the built environment has a major task to reduce the CO2 emissions and convert to sustainable energy systems. The energy saving targets are high and there is a need to show in a non controversial way the achievement of the various Member States. This is one of the reasons that harmonised calculation procedures, including harmonised input parameters, are desirable. However there are still a lot of national differences in the various regulations directly influencing the EP requirement level; for example the requirements on ventilation or other health related issues. The EN 15251 “Indoor Environmental input parameters for design and assessment of energy performance of buildings addressing indoor air quality thermal environment, lighting and acoustics “ has been developed to give the MS regulators the opportunity to harmonise these requirements.
See also question "What are the future prospects for the status of the CEN standards?" and other related questions.
Question submitted by: Dick van Dijk (TNO, The Netherlands)
Anwered by: Dick van Dijk, TNO and Jaap Hogeling, ISSO (The Netherlands)
Date: 10/03/2008
The energy performance of products is taken into account in an indirect way. The EPBD CEN standards are generally dealing with performance description of buildings and systems. The EPBD standards describe the way the system performance has to be determined. These values are influenced by the relevant product specifications. The standards developed under the EPBD either refer to relevant product standards or specify the required input for the system standards.
Question submitted by: Dick van Dijk (TNO, The Netherlands)
Anwered by: Dick van Dijk, TNO and Jaap Hogeling, ISSO (The Netherlands)
Date: 10/03/2008
This is up to the National Standard Body, most countries offer both possibilities.
Question submitted by: Dick van Dijk (TNO, The Netherlands)
Anwered by: Dick van Dijk, TNO and Jaap Hogeling, ISSO (The Netherlands)
Date: 2008/03/10
EN ISO 13790 describes calculation methods for the energy need for heating and cooling for each building zone, whereas EN 15603 deals with the overall energy use and the energy performance of buildings, collating the results from other standards, including those from EN ISO 13790.
More information: CENSE Information Paper P095 which can also be downloaded from the BUILD UP Portal.
Question submitted by: Dick van Dijk (TNO, The Netherlands)
Anwered by: Anna Staudt and Hans Erhorn, Fraunhofer Institute of Building Physics (Germany)
Date: 2008/02/04
The primary advantage of the more detailed and thus more advanced method (holistic approach) is the higher quality and reliability of the results, due to the very realistic model on which the calculation is based. The intermediate results are quite exact and very appropriate for further more detailed analysis. Its main disadvantages are the need for suitable computer software for the complex calculation and the longer time required to perform the calculation.
The advantages mentioned above represent the disadvantages of the simplified approach, which uses a very approximate model. Nevertheless, the results can definitely be used to assess and compare the energy performance of simple buildings with conventional performance. The advantages of the simplified approach are the shorter time required to perform the calculation, and the fact that it can be done by hand.
More information: CENSE Information Paper P095 which can also be downloaded from the BUILD UP Portal.
Question submitted by: Dick van Dijk (TNO, The Netherlands)
Anwered by: Anna Staudt and Hans Erhorn, Fraunhofer Institute of Building Physics (Germany)
Date: 2008/02/04