Carbon-neutral shopping in the zero:e park
The REWE store in the zero:e park is Germany’s first supermarket recognised by the Passive House Institute (PHI) to have such well-engineered design to the Passive House standard. This reference project has been devised in conjunction with developer ‘meravis’, the PHI in Darmstadt, energy expert Dr York Ostermeyer and the REWE Group. The innovative energy concept has been specially developed for this construction project and thus provides a benchmark for future Passive House supermarkets. The building was designed by Hamburg-based architectural consultants Spengler and Wiescholek.
The REWE branch has a sales area of 1,300 square metres. What makes it special is that its low energy requirements mean emissions of the greenhouse gas carbon dioxide are 30% lower than for conventional new supermarket builds on this scale.
In contrast to residential buildings, the energy needs of a supermarket are not influenced as much by the quality of the building envelope, but primarily by food refrigeration and lighting. Refrigeration accounts for around 60% of total energy consumption and lighting for 20%, so it is here that the biggest savings can be achieved.
Food refrigeration provides space heating
The store does not have a conventional heating system for space heating. Heating requirements are met primarily by waste heat from the refrigeration system. Only on very cold days, when this exhaust heat is not sufficient, is an outdoor-air heat pump used. In summer, however, the heat can be efficiently diverted outside without heating up the sales area. Instead of a number of compression chillers, refrigeration takes place centrally in what is known as a compound chiller. Throughout the store, only market-leading, highly efficient refrigeration units are employed. Some of these are models that have never been created in this form before.
The lighting is particularly energy-saving: it requires a mere 12 watts per square metre of the energy reference area. Other supermarkets of comparable size consume around 25 watts for the same light output.
DGNB award for sustainability
The new REWE store has been certified by the German Sustainable Building Council (DGNB). This DGNB certificate is a nationwide distinction established in conjunction with the German Federal Ministry of Transport, Building and Urban Development. The DGNB system assesses a building’s overall performance as opposed to individual measures. This endorsement is awarded for the outstanding fulfilment of up to 50 sustainability criteria relating to ecology, economics, sociocultural aspects, technology, process workflows and location.
Support from proklima
The building of the REWE supermarket is also being supported by the proKlima climate protection fund, which is being financed by the city of Hannover and the towns of Hemmingen, Laatzen, Langenhagen, Ronnenberg and Seelze as well as by the ‘enercity’ utility. Criteria for funding are CO2 efficiency, absolute CO2 reduction, the multiplier effect and the innovativeness of the measures.