Case study on EN-ISO 52000-1 Overarching standard - Weighting factors
Understanding the weighting factors is a critical step in using EN-EPB standards as well as any other alternative energy performance calculation procedure. The weighing procedure is the interface between the building calculation and the external world.
Any calculation about the building will end-up with an amount of energy carriers that are imported and exported. The raw “kWh” information is not enough to characterise neither their energy impact nor their environmental impact (though energy impact can be considered one possible type of environmental impact). The “weighting”, associates an amount of a “weight” to each unit of imported or exported energy carrier. This allows to evaluate any specific impact on the environment of the provision of EPB services to a building.
Each kWh of imported (or exported) energy carrier will have an impact in terms of:
- non-renewable primary energy, that is natural resources depletion;
- CO2 emission, which should include both local (CO2 in flue gas after local combustion, for fuels) and external (CO2 emission when producing and/or transporting the energy carrier), that is GHG emissions;
- polluting emissions, typically from combustion of fuels, which may local or remote;
- any other measurable impact, such as e.g. water use.
When drafting EN ISO 52000-1 a number of conceptual issues about energy weighting had to be analysed and incorporated in the calculation methodology.
A first example is the evaluation of exported energy, which can be done in two different ways. Since MSs did different choices, the calculation procedure in EN ISO 52000-1 had to include a number of parameters, such as kexp, that allow to switch the approach within the same calculation scheme.
This simplified case study complements the regular case study on EN-ISO 52000-1 with a set of focused simplified examples. It is a collection of simple cases that cover specific impacting features of EN-ISO 52000-1. The simplified cases allow to concentrate on single aspects of the standard without the noise and disturbance of the high number of parameters and the time dependence of actual cases.
This study concentrates on the following concepts, with the help of a series of videos:
- primary energy concept and delivered energy weighting - See video on Primary energy
- exported energy weighting, basics - See video on Exported energy, basics
- exported energy weighting with kexp = 0 - See video Exported energy, option A in detail
- exported energy weighting with kexp = 1 - See video Exported energy, option B in detail
- renewable energy ratio (RER) - The renewable energy ratio evaluation and the dependency of RER range on kexp choice is detailed in the previous short videos about exported energy in details; - See video on Exported energy and impact of calculation interval
- Application to the main generation technologies; - See video on the accompanying excel (insert link) with simplified cases for a resume of the previous concepts and an example of the application to the main generation technologies
It is recommended that you watch the videos following the sequence shown in the table.
More details on the calculation methodology and the impact it has on various building types, either residential or corporate, can be found in the full document, which can be accessed at the link below: