B-17 Operational energy demand for new buildings – Boundaries and scenarios for screening LCA

Aspect B-17 Operational energy demand for new buildings – Boundaries and scenarios for screening LCA
Description
Several parameters can influence the results of the energy demand at the operational stage of buildings. Among others, the selection of uses (i.e. building-related or non-building-related uses) has a major significance on the energy demand. European standards (EN 15804/EN 15978) recommend that priority be given to taking building-related uses into account; however, it is obvious that non-building-related appliances significantly influence the energy needs of building-related uses (e.g. the thermal gain of appliances decreases the level of heating demand). How can this aspect can be addressed in screening LCA of new buildings?

related study objective

stand-alone LCA comparative assertion

related study phase

goal and scope definition inventory analysis (LCI) impact assessment (LCIA) interpretation reporting

relevant for

new buildings existing buildings construction products screening LCA simplified LCA complete LCA
Provisions For screening LCA of new buildings, building-related uses should be accounted for. Other uses may be included according to the object of the assessment. For screening LCA, simplified approaches for calculation or estimation of the operational energy use may be used.
Rules from:
EN 15978:7.4.4.7 Boundaries for operational energy use

8.6.5 Scenarios for operational energy use – Module B6

Guidance
For screening LCA, building-related uses defined according to the Energy Performance of Buildings Directive (2002/91/EC) should be accounted for, possibly by the use of simplified calculation methods or estimates, as specific, detailed energy performance calculations may not be available in the early design stages of a building.The expected performance target for the building may be used to estimate the operational building energy demand. The performance may correspond either to energy label targets or to reference levels set by a national regulation. Energy demand should at least be calculated for building-related uses covered by the EPBD directive (heating, cooling and air conditioning, ventilation, domestic hot water, lightning and auxiliary energy used for pumps, control and automation).The breakdown of the energy demand for each energy carrier may be derived from the energy target according to the expected integrated systems (boiler, ventilation, lighting and cooling systems etc.).

Other energy uses may be included and calculated with the help of conventional or statistical data.

Link between energy consumption values and environmental impacts

Once the energy consumption values are calculated, they need to be associated with generic or specific LCA data for the corresponding process. For example, the number of kWh of electricity in a French building project should be associated with the generic LCA data representing the average mix for the French context.

Other energy sources such as fuel, natural gas, wood and district heating also need a generic LCA data describing only the combustion. To this purpose, the infrastructure (e.g. the boilers) should be accounted for as technical equipment. This equipment contributes to the embodied impacts of a building along with the building products.


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