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The first passive house primary school in Saxony-Anhalt built as sustainable and ecological design consumes less than 90 per cent energy than comparable primary schools.
© Hochschule Magdeburg-Stendal
New construction school
Projektinfo 11/2018

Ground floor plan of St. Francis Primary School (plant rooms, sanitary spaces, school kitchen with assembly hall and after-school care centre)
© Steinblock Architekten

Measures and components in the building
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Passive House primary school in Halle undergoes monitoring

The ecclesiastical funding body wanted to use ecological building materials for the construction of a new primary school and, with the energy-optimised building, ensure a high degree of learning comfort with manageable operating costs. This resulted in the first Passive House school building to be constructed using a timber frame structure in Saxony- Anhalt. Multi-year monitoring and accompanying sociological research have verified both its energy efficiency and acceptance. The new building consumes 90 per cent less heating energy than comparable primary schools in Germany, but still has reserves in terms of the electricity consumption. The school forms part of the nationwide EnEff:Schule research initiative implemented by the German Federal Ministry of Economic Affairs and Energy.

St. Francis Primary School in Halle, which opened in February 2014, provides two parallel classes in each year. It offers 200 pupils in the classrooms, after-school care centre and assembly hall a pleasant indoor climate and an attractive setting for motivated learning and teaching.

The funding body, the Edith Stein School Foundation from the Diocese of Magdeburg, had requested a sustainable and ecological structure built to the Passive House standard. “Responsibility to ourselves and our children requires a clear shift toward energy conservation and the efficient use of the resources entrusted to us. Our commitment to the integrity of creation should be clearly reflected in the new building for St. Francis Primary School and thus become a model for other construction projects, including in our diocese,” says Foundation Director Steffen Lipowski. The building is almost completely constructed as a timber frame structure, largely from renewable raw materials and recycled building materials. The three-storey school building, which does not have a basement, consists of two staggered, almost equally sized rectangular blocks. The building includes classrooms, an after-school care centre, administration area, caretaker‘s flat, school kitchen and assembly hall. The building is built to the Passive House standard, but is not certified by the Passive House Institute in Darmstadt.

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Building in detail

In order to achieve the required Passive House standard, the building envelope was constructed with high thermal insulation and, as far as possible, without thermal bridges. The designers opted for a timber frame structure, of which 80% consists of renewable resources. This also took into account the desire for a sustainable and ecological construction method. The structure of the outer wall is constructed using double-T timber beams, with the voids completely filled with cellulose. The U-value of the external components ranges between 0.10 and 0.16 W/m2K. The construction method with large amounts of renewable (timber, cellulose) or recycled building materials (concrete and foam glass ballast) is very compact. Even three years after going into operation, the air tightness still attains a very good value of n50 = 0.26 h-1.

Six ventilation systems with heat recovery ensure sufficient fresh air. Presence detectors in each classroom and carbon dioxide sensors in the assembly hall control the airflow rate.

The building is heated by the ventilation systems; just four offices with low external heat are equipped with electric radiators. This air heating, which uses the district heating return line from a neighbouring secondary school, provides the school with the required space heating.

To warm the domestic hot water for the school kitchen and the caretaker‘s flat, the south-facing facade is equipped with solar thermal systems with a 36 m2 collector surface which feed the solar heat into a 2 m3 stratified storage tank. Peak load coverage is provided by an integrated 9 kW electric heating element. There is no auxiliary heating using a district heating heat exchanger, as originally planned, because the supply temperature of the district heating is too low at 45 °C. It was also initially planned to supply surplus heat from the solar thermal system to a latent heat storage system. However, the salt hydrate storage tank is practically never used, as there is hardly any surplus heat once the two other storage tanks have been charged.

The water heating for the remaining school operation (sanitary facilities) is provided by local water heaters.

Two grid-connected photovoltaic systems with a total output of 78 kWp mainly supply the ventilation systems as well as the energy-intensive operation of the school kitchen. This provides up to 300 meals on normal school days for pupils from both the primary school and the neighbouring secondary school. A micro-wind turbine with a 1 kW capacity was installed, but this has failed to prove itself in practice as a result of huge downtime losses. The likewise envisaged battery storage system with a 25.6 kWh storage capacity was used for just a few weeks before completely failing due to a technical issue.T he school is not planning to replace it at the moment.

Projektinfo 11/2018:
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Links

St. Francis Primary School
Website of the primary school in Halle (in German)

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