3. Good Practice Example: Climate Protection Estates zero:e park (Hannover, Germany)

Transcription

1 3. Good Practice Example: Climate Protection Estates zero:e park (Hannover, Germany) Keywords Climate Protection Estates, zero-emission residential estates, passive houses, building envelope curve Name and location Binding Land-Use Plan Climate Protection Estates zero:e park, Hannover Europes biggest innovative climate protection estates for about 300 townhouses, duplex and detached single-familiy and passive houses in zero-emission residential estates. Thematic focus: Binding land-use plan Climate Protection Estates zero:e park Area size: 25,5 ha, residential and special area Implementation phase: Figure 1: Surroundings of the planning area and adjacent binding land-use plans.

2 Source: City of Hannover. Key elements of the zero:e park are: Construction of passive houses over a wide area Reduction of the remaining energy requirement by means of solar thermal energy The use of energy-efficient household appliances The offsetting of residual CO2 emissions for heating needs and household electricity requirements via a regenerative power plant Background, objectives, implementation measures and financing Concept In Wettbergen, in the south-west of Hannover, Europe s largest innovative climate protection housing development is emerging, with some 300 terraced, semi-detached and detached houses designed as Passive Houses in a zero-emissions estate. The intention is that the residual CO2 emissions generated by remaining energy requirements and the still-needed household electricity will be offset in a climate-neutral manner by reactivating an abandoned hydroelectric power plant. As well as CO2 neutrality, provision is made for the construction area which shall provide a quality of life as good as possible with green space of superior design and a water concept.

3 Figure 2: Construction stages 1-3. Source: City of Hannover. Implementation An offsetting zero-emission development: The basic principle behind the development s energy concept is energy-efficient design to reduce the houses heating requirements to a minimum. Both passive and active utilisation of solar energy are involved so that, when combined with the use of renewable energy, there remains only a small energy requirement outside the housing development to be offset. Solar-optimised development plan: Full use of the opportunities provided by building legislation has been made in order to offer house-builders ideal conditions for constructing homes that are especially energy-saving. The buildings should be as compact as possible, with optimal solar access without shading by adjacent buildings. Even at the urban land-use planning stage, a basic framework and conditions encouraging solar-optimised design similar to that of the Passive House are being created in Hannover. The following aspects come under consideration in urban land-use planning: Compact nature of structures South-facing orientation of housing blocks, rooftops and principal rooms intended for continuous human occupancy Ensuring solar energy can be used by providing shade-free façades and rooftops and through structural relationships (building heights and spacing) To prevent adjacent buildings being shaded (including at times when the sun is low), and to ensure the housing blocks are structurally compact, it was stipulated for this development plan

4 that buildings would have two full stories, with height specifications drawn up in the form of an envelope curve. Figure 3: Structural limits determined by an envelope curve stipulated as part of the development plan. Source: Zero:e park. This envelope curve stipulates spacing and height limits for the future structures. Within this specification, the house-builders have considerable latitude with regard to the shapes of buildings and roofs, so that architectural distinctiveness and excellence can be achieved. Passive houses: A passive house is a building standard that is truly energy-efficient, comfortable, cost-effective and environmentally friendly at the same time. Passive House is not a brand name, but a tried and tested construction concept that can be applied by anyone, anywhere. However, a Passive House is more than just a low-energy building: Passive Houses consume 90% less thermal energy than typical building stock and, even in comparison with average new builds, allow for savings of over 75%. Passive Houses use the equivalent of around 1.5 l of oil to heat one square metre of living space for a year substantially less than other low-energy buildings. Heating remains affordable even in times of crisis. Special windows and a building envelope consisting of a roof, floor slab and exterior walls all with highly efficient insulation keep the desired warmth in the house. Passive Houses use energy sources available in their interiors such as body heat or incident solar heat which radically simplifies heating. Comfort is also considerably enhanced in a Passive House. A ventilation system with a highly efficient heat recovery unit enabling the heat contained in the exhaust air to be re-used makes for a constant supply of fresh air without draughts. High surface temperatures (differing only slightly from those of the indoor air) ensure a thermal feel-good factor. Figure 3: Functioning of a passive house.

5 Source: Zero:e park. The water and greenspace concept: For the planned development area the housing estate, which will be directly adjacent to a landscape conservation area, is to receive particularly valuable open space with green corridors and a water concept. The rainwater will infiltrate on-site in a soakaway system (Mulden-Rigolen-System) so that the same volume of water drains away as before. Overall, the water resource management concept will enable the rate of groundwater recharge and evaporation to be largely maintained. This will achieve a preventive flood control effect, averting additional charging of the Hirtenbach stream even during heavy rainfall. Between the construction sections, a green window onto the countryside will be created. This will link up the greenspace from the Hirtenbach stream to the municipal cemetery in Ricklingen, and thus continue to ensure the influx of fresh air from the hinterland to the districts adjoining the planning area. Cost benefit, effects and results achieved Per house: average remaining CO2-emission of 900 kg/year and thereby a reduction of greenhouse gas emissions for heat of 65-87% (in comparison to buildings constructed under legal stands (EnEV 2009). Planning procedures, involvement of stakeholders and possible

6 participation structures Since 2008 the city of Hannover has been implementing a climate protecting programme implemented within the Climate Alliance Hannover In this alliance 80 partners agreed to reduce the CO2-emissions by 40% by It intends also to set specifications in ecological standards building new houses. Thus aspects of climate protection has to be considered within the binding urban land-use planning, urban development contracts as well as land sale contracts. The goal is to keep CO2-emissions in new building areas as low as possible. Figure 4: Draft for single-family houses. Source: Zero:e park. To reduce the heat demand to a minimum the urban development contract pretends to set an extensive building with passive houses as basic principle. This is supplemented by the limitation of the primary energy demand to 40kWh/m²a, the obligation to use solar energy for warm water demand and the obligation to make use of an energy consulting bevor buying a site. Information is available to families building their own homes who wish to plant up their own properties; this contains recommendations on what to plant to minimise shading. The architects and landscape architects have produced a booklet on behalf of the municipality. The binding land-use plan provides appropriate measures for central solutions where town houses are planned. Innovation fostered - local / regional developments triggered Energy concept standards in passive houses, solar energy plants and compensation of remaining CO2-emissions Water concept soakaway system

7 Green concept suitable green planning for passive houses Living neighbourhoods project consulting, campaigns and evaluation of the estate area Consulting integrated and obligatory energy saving consultation