Vistar Passive House³ (Premium)

Energy efficiency without added costs

Building energy-efficient new buildings costs more – this is a preconception that has been hard to shake. But B+P BauConsult GmbH in Mülheim an der Ruhr shows that energy efficient construction doesn't always need to be expensive: in Wuppertal, the company is building North Rhine-Westphalia’s first new building to meet Passive House Premium Standard (Passive House³). Not only will the building have exceptionally low energy requirements, which it will meet with its own sources of renewable energy, but taking into account public funding, this construction method offers competitive prices when compared to standard construction costs.

This multi-family house with 18 residential units and an underground garage with 19 parking places is being built as a 3rd generation (Premium) passive house, the highest passive house construction standard at the time. Passive houses significantly reduce the energy consumption of buildings. In addition to the usual requirements of a passive house, the renewable primary energy requirements (PER requirements) of premium passive houses (Passive House³) may not exceed 30 kilowatt-hours per year and square metre (kWh/m²*a) of energy reference area. In addition, the building must generate a minimum of 120 kWh of electricity per year and square metre of built-over surface. Compared to a normal passive house, these requirements cut consumption values in half.

Engine for progress:

  • NRW’s first new building to meet premium passive house standard (Passive House³).
  • Primary energy values total just 6.6 per cent of the values for a comparable energy-saving (EnEV) reference building.
  • Demonstrates that with adequate support, highly efficient designs don't need to be more expensive.
  • Innovative use of existing waste heat from photovoltaic systems to heat the building in winter

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Photo: W. R. Bouchard

The Vistar-Passivhaus³ is built in Wuppertal-Hecklinghausen with a total of 18 residential units and 19 underground parking spaces.

Maximum energy standards at minimal costs

The Wuppertal construction project has even more advantages: upon completion, the building’s primary energy requirement will total no more than 6.6 kWh/m²a. That corresponds to just one tenth of the primary energy needs of a “normal” energy-saving reference building, which is a building that meets current energy savings regulations in Germany (EnEV). The heating requirements are calculated at just 9.5 kWh/m²a, a heating load of only 7.6 watts per square metre. In combination with efficient technology, this saves around 80 tonnes of CO2 emissions per year, compared to an energy-saving reference building. In order to keep construction costs low despite high energy standards, the project involves as much preliminary work as possible: for one thing, industrially pre-assembled wall components that – much like in timber frame design – feature a wall surface that is made to be so smooth as to not require any additional plastering. A much cheaper coating is sufficient. All the electrical sockets are also pre-installed in the walls, removing the need for milling and tediously laying cable at a later point in time. Precision fitting and perfected construction methods, just like the auto industry applies to its products, have been and continue to be target requirements for cost-effective construction management.

Climate-friendly building technology

The money saved through these processes is invested into modern technology. That includes outfitting 105 m² of the building with a proprietary hybrid PV/solar thermal energy system, which actively cools the photovoltaic panels in order to increase the solar cells’ efficiency by up to 25 per cent. The waste heat this process creates is stored in an array of probes underground, until it is used to heat the building in the winter, using a heat pump with a significantly improved annual coefficient of performance. Another 90 m² of the roof’s surface is covered with simple photovoltaic modules. A controlled residential ventilation system with waste heat recovery ensures that over 85 per cent of the heat from the exhaust air is recycled and remains in the building’s system. The photovoltaic system and a 5.0-kWh fuel cell plant cover the building's entire energy requirements. The electricity produced is stored in a battery system with a capacity of 78 kilowatt-hours, so that the building may achieve the maximum level of self-sufficiency. A natural gas-powered PEM low-temperature fuel cell plant additionally contributes to the electricity supply, for a maximum thermal output of 7.5 kilowatts, which is used to heat water and for supplementary heating. Another point of interest is the planned vehicle-to-home connection for a Nissan Leaf, which will be made available exclusively to the building's residents through a car-sharing programme, thereby increasing the building-related battery storage capacity by an additional 40 kilowatt-hours.

By implementing climate-friendly building technology, together with the Passive House³ standards governing the building’s construction, on balance, the total energy requirements can be met through renewable energy. This means the degree of self-sufficiency is expected to reach up to 66 per cent for electricity, and up 90 per cent for heating.

Climate-neutral housing stock by 2050

Reducing the energy consumption of buildings is a core part of German climate policies. In 2016, Germany's building-related energy consumption stood at around 3,234 petajoules. That corresponds to around 35 per cent of the nation's total final energy consumption, and around 30 per cent of its CO2 emissions. By 2050, the German government aims to have achieved a nearly climate-neutral housing stock. In order to reach this goal, a greater proportion of heating requirements must be met using renewable energy, and the number of energy efficient buildings must increase. The project could trigger increased demand for energy efficient new buildings, since it shows that through careful planning and design, even a highly efficient building can be competitively priced compared to similar new buildings that merely meet EnEV regulations.

Photo: W. R. Bouchard

“One day, our children will ask us why, even though we knew what was coming, we chose not to do anything. Instead of talking, let’s get to work, rather than leave future generations incapable of paying for what needs to be done.”

Winfried R. Bouchard, managing partner for B+P BauConsult GmbH

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