CENSE

Can the calculation method for the overall transmission and ventilation heat loss coefficients, which is presented in EN ISO 137

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

Can the calculation method for the overall transmission and ventilation heat loss coefficients, which is presented in EN ISO 137

Many CEN-standards are ISO-standards, e.g. EN ISO 13790, 6946, 10077 and 14683. How can these standards make reference to the se

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.

Many CEN-standards are ISO-standards, e.g. EN ISO 13790, 6946, 10077 and 14683. How can these standards make reference to the se

why was the term “heat transfer” introduced instead of “heat loss” in the CEN standards to support the EPBD?

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.

why was the term “heat transfer” introduced instead of “heat loss” in the CEN standards to support the EPBD?

Where can I find background information and more technical information, concerning the content of EN ISO 13790?

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

Where can I find background information and more technical information, concerning the content of EN ISO 13790?

Regarding the methods offered for the calculation of energy needs in EN ISO 13790. What is the difference between the monthly me

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

Regarding the methods offered for the calculation of energy needs in EN ISO 13790. What is the difference between the monthly me

Are the methods validated, which are offered for the calculation of energy needs in EN ISO 13790?

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

Are the methods validated, which are offered for the calculation of energy needs in EN ISO 13790?

Why are different methods offered for the calculation of energy needs in EN ISO 13790?

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.

Why are different methods offered for the calculation of energy needs in EN ISO 13790?

Is there a roadmap or guidance to achieve one European calculation method on the energy performance of buildings?

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.

Is there a roadmap or guidance to achieve one European calculation method on the energy performance of buildings?

How can I make the energy performance of systems visible on the Energy performance certificate (the energy label)?

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

How can I make the energy performance of systems visible on the Energy performance certificate (the energy label)?

Are the products, building products and systems, taken into account in the EPBD standards?

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.

Are the products, building products and systems, taken into account in the EPBD standards?