Construction Management
3.
Modernisation or replacement of heating systems
4.
Greening and redesign of inte- rior courtyards
Heating the interior rooms is responsible for roug- hly 80 per cent of household energy on average, while a further 10 per cent is required for warm water preparation. An efficient heating system that uses renewable energy sources can signifi- cantly reduce primary energy consumption – and also cut CO2 emissions by at least two-thirds (depending on the initial values and the heating system). The combination of several systems (e.g. geothermal with solar power and heat recovery) can lead to even better results. Planning for the conversion from fossil heating systems to a central, more sustainable system is, therefore, essential. Alternatives include air-air or air-water heat pumps, geothermal energy or district heating. Solar thermal technology and photovoltaics can, as a rule, make an additional contribution or improve the ecological quality of the primary heating system. For technical reasons (limited space, access roads, statics etc.), many advantageous alternatives are not possible or economically not viable. In order to cover electricity requirements – e.g. for a heat pump – the installation of photovoltaic equipment on the roof is recommended and, in particular, generates added energy revenue during the summer months. Solar thermal energy is a practical combination alternative for heat generation. The combination of solar thermal technology and a conventional heating system can normally be configured so the solar compo- nent will cover warm water requirements and the heating system will only be activated when additional energy is needed. A ventilation system with heat recovery contribu- tes to energy efficiency just the same as a less expensive wastewater heat pump. Other options to consider from a sustainability (and partially also from a cost) viewpoint include the use of rainwater for green areas and the recycling of process water.
Rainwater management and the moisture stored through greening as well as enlarged seepage areas are a counterpoint to urban heat islands and tropical nights. Greening reduces the heat build-up in a building and, where light conditions, temperature and humidity as well as air circulation and comfor- table interior temperatures are also considered, also transforms ecological measures into a feel-well factor.
„ESG measures can create added value for users “
Many inner courtyards have plenty of available space for gardening. Cool inner courtyard faca- des routinely receive little attention but provide a welcoming climate for a trellis as support for ground-based climbing plants. Additional greening is not only a source of cooling and natural shading for the building, it creates high-quality open space and interactive areas for residents and, in that way, strengthens social interaction.
5.
Multiple building measures
The possibilities to achieve decarbonisation with projects at the individual property level are limited or inefficient and, consequently, measures that cover multiple buildings are necessary in the areas of heating, cooling and warm water. Sample pro- jects are few, but very successful and underscore the potential for cooperation at the housing block level. In many cases, the use of sustainable energy sources is only possible with this multiple buil- ding approach and it almost always significantly improves cost efficiency. The main problems here are not the technical challenges, but legal issues and the fair reconciliation of interests between the various property owners.
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