Figure 332


Source: Carsten Petersdorff

Figure 3.3.5 Annual primary energy for heating and construction per house

Source: Carsten Petersdorff

Figure 3.3.5 Annual primary energy for heating and construction per house

The infrastructure

The infrastructure of the settlement includes roads, sidewalks, park surfaces and garages, as well as wires for electricity and communication, and pipes for gas, water and wastewater. The CED breakdown is presented in Figure 3.3.2. It is surprising that the construction of the sewage system represents higher energy expenditure than the much larger traffic surface. This is caused by the comparatively low CED value for road surfacing, since bitumen is a petrochemical by-product. The large mass of energy-intensive materials (for example, cement) for paving, concrete curbs and park surfaces are the main sources of the CED for the traffic infrastructure.

The buildings

Figure 3.3.3 compares the CED of the different house types. The building envelope accounts for approximately 90 per cent of the CED! Interior fittings and services (gas, water, heating and electricity installation) represent 7 per cent of the CED. The solar systems make up the remaining 3 per cent, of which the greatest cause is the photovoltaic system.

The wooden frame houses (Quattro) and massive houses with similar structure (Optimo) allow a comparison of the two constructions. Results are separately illustrated in Figure 3.3.4.

The direct comparison shows that wood frame construction has a 20 per cent lower CED than the massive construction. This is partially explained because the internal energy of the wood is rated as neutral. The strong influence of concrete becomes clear by comparing the houses in light construction with and without cellars. Adding a cellar increases the CED by approximately 22 per cent.

Comparison of CED and energy for heating and electricity

In addition to the energy input for construction, maintenance and decommissioning, energy is, of course, consumed during its operational lifetime. This includes energy used for household electrical appliances, hot water and space heating.

Energy used during the operational life time accounts for an overwhelming 85 per cent of the primary energy used. While electricity and hot water demand primarily depend on user behaviour, the space heating demand is strongly correlated with the insulation quality and ventilation system of the building. Over 50 years, the primary energy demand for heating alone amounts to approximately 22 GWh per house and is therefore in the range of the primary energy use for construction, maintenance and decommissioning (see Figure 3.3.5).

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