Heat Pumps in the German Federal Environment Agency
Overview
With reduction of energy consumption at the heart of the German Federal Environment Agency’s goal, the building was set out to be constructed in a manner that integrated types of renewable energy to create a sustainable system. As part of this endeavour, special attention was given to creating a space that was insulated enough to retain heat/cold and be compact in design. What was created was a building that did just that, while employing the usage of solar and geothermal energies to meet 15% of the total energy requirement.
The constructed low energy building boasts usage of PV, solar collectors for cooling, and a geothermal heat exchanger for heating.
A second building for the Geman Umweltbundesamt was opened early September 2023 in Dessau-Roßlau, boasting that it is 100% climate-neutral while conserving resources and even generating additional energy (not for self-consumption) when possible. Construction of the secondary space began back in 2016 was built to offer sufficient space for the UBA employees—something very much welcome, considering the Agency has grown from 750 to ~1,150 employees in the last ~20 years.
Investment history
The project for building one had a net cost of around €76 million and was built between 1998 and 2005 with Berlin-based, Sauerbruch Hutton Architekten. The cost of building two was €13.5 million in total.
Technical aspects
Building 1’s geothermal heat exchanger is made up of four fields total (depth 3.7m, 3m long, walls 18cm thick), that together form a subterranean system of pipes reaching a combined total length of 5 km. Outside air enters the through three intakes from the west and is fed to four air units in the building. There are five intake structures through which the airs is fed. Each are 3-4m high, with three feeding the air through the grid pipes to pre-condition and another two which pass the air into the building at certain temperatures. This allows for the air exchanged through the geothermal heat exchanger and delivered into the working space to be cleaner than the ambient air. The ability of the ground to store heat allows for the ambient air to be heated in winter and cooled in summer as needed. In summer, the geothermal heat exchanger cools the 32°C warm air down to 20°C, which is then circulated through the building offices. In the winter, the outside air can be warmed up (e.g. -10°C to 4°C). the total heat gains from the system for 2009 were 74MWh and the cooling was 39 MWh (~5% of total energy consumption). (Additional information on the heating and cooling aspects can be found here)
The Agency’s second building uses a PV system spanning the façade and roof which covers 830m2. This is complimented by a heat pump connected to 32 geothermal probes that offer 54 kW.
Summary
Depth of drilling: 3.7m
Total length of wells: 5km
Geothermal power: 86,000 kWh heat produced (winter) 125,000 kWh cold produced (summer)
Units covered: 8,700 m2 of floor space
Total amount of investments: ~€76 million (building 1) €13.5 million (building 2)