THE PLAN AWARD 2019

Klimapositive Plus-Energie-Schule
Beim neuen Fachklassentrakt für Biologie und Chemie handelt es sich um ein Null-Energie-Gebäude. Der Technikeinsatz wird durch ein integrales Klimakonzept minimiert, das die natürlichen Prinzipien wie Licht, Thermik und Erdwärme maximal ausnutzt. Dadurch reduzieren sich die Betriebskosten für die Hauptenergieverbraucher Kunstlicht und Lüftung. Eine ressourceneffiziente und kompakte Bauweise steigert zudem die energetische Qualität des Gebäudes und reduziert den Energieverbrauch. Eine Photovoltaikanlage dient der Stromgewinnung. Bei einem Schulgebäude bietet sich dies an, da Energiegewinnung und Verbrauch im Gegensatz zu Wohngebäuden zu gleichen Zeiten stattfindet. Damit ist eine (unwirtschaftliche) Einspeisung ins Netz nicht erforderlich.

LOW TECH - HIGH COMFORT
The school’s new science block is a zero-energy building, which means that it produces – locally and renewably – the same amount of energy as it consumes. This balance includes both the energy used in heating, ventilating and lighting the building and that required to power the equipment operated within it. The new building offers a conscious alternative to the rampant use of technology in buildings and requires no high-tech, maintenance- and cost-intensive air conditioning or heating plant. It’s an active building utilizing environmental energy sources in a maximum way. It’s architectural and climate control concepts reduce the operating costs of artificial lighting and heating, the biggest energy consumers. According to the current status of monitoring the building is climate-positive in its operation: around 5 tons of CO2 are saved annually
With a large percentage of urban building space being occupied by schools whose day-to-day operation and maintenance costs represent a significant item in local authority budgets, intelligent school design can both help achieve significant resource and energy savings and increase comfort levels. Thanks to the use of environmental energies, the science block enjoys high levels of natural lightning and thermal comfort, which in turn provides the basis for efficient, performance-enhancing working. Alongside good room acoustics and carefully chosen surface materials, the school building offers a high-quality interior environment. This fosters a sense of wellbeing that increases user acceptance, reduces vandalism and helps creates identity and identification.

BUILDING WITH ENVIRONMENTAL ENERGY, NOT COMPLEX PLANT AND TECHNOLOGY
To achieve a zero energy standard, alongside the climate control concept the architects developed a low-energy, site-specific building design whose compact, resource-efficient construction increases the energy quality and reduces the energy consumption of the building. The framework is a hybrid timber-and-concrete structure with a careful balance of eco-friendly timber and solid components acting as heat and cold buffers. In summer, the concrete walls store the night-time cool that penetrates the building via the openable ventilation panels. This provides pleasant daytime temperatures without the need for high-tech air conditioning plant. During the record temperatures recorded in July 2019, heat storage in conjunction with this natural night-time cooling made sure that daytime temperatures inside the building never exceeded 24-25°C.

The fresh air used to ventilate the building is supplied via a 45m-long underground conduit that exploits the natural difference between ground and external air temperatures, cooling the air supply naturally in summer, preheating it in winter. Even at low outside temperatures, this system can guarantee air quality economically and efficiently without draughts and so ensure constant CO2 levels in the classroom. This is important because windows cannot be opened during lessons due to street noise and brief bouts of natural ventilation during breaks alone would be insufficient to achieve the necessary air exchange. The result would be an increase in CO2 levels and the associated tiredness, performance loss and increased risk of the spread of germs.

INTERNAL EXCHANGE NETWORK MEANS THAT 1+1=1
As energy is produced and consumed simultaneously, the building generates electricity by means of a photovoltaic system, while an internal network allows energy exchange between the main and new buildings in a relationship that benefits them both. In winter, the heating system in the main building easily covers the low heating demand in the new science block, which does not therefore require a heating system of its own. In summer, the excess energy produced by the photovoltaic system is supplied to the main building. The result is a new school building with no added energy costs.

OPTIMUM CONDITIONS FOR SUCCESSFUL LEARNING
Room climate und lighting conditions have a demonstrable impact on educational success. Pre-construction trials with various different roof shapes revealed that the north-facing shed roof design provided the highest levels of daylight yield for the new science block. Lighting uniformity is a significant factor here since poorly distributed, individually lit surfaces provide insufficient illumination and lead to strong contrasts and glare.

INTEGRATION OLD AND NEW
Sunk partially into the ground to retain the view of the listed main building, the new science block has been incorporated into the school’s existing spatial geometry, thus moulding the various buildings into one coherent complex.