Social housing block from the 1950s gets a ‘green’ heating system
System C renovation – over 150 apartments are now climate-neutral
Building cooperative decides to heat over 70-year-old residential complex with heat pumps in the future
Project facts
Measure
- Modernisation of the heating system: Conversion of a social housing block from the 1950s with 150 residential units from a gas central heating system
- Heat distribution Steel panel radiators
New heating technology
- 15 air-to-water heat pumps LA 35TBS
Special features
- Different spatial conditions for the heating stations – in some houses on the top floor, in some in the basement
- Insulation of the attic and the basement ceiling
- No facade insulation possible, because parts of the building are under preservation order, such as the glazed, front-mounted stairwells, several terracotta frescoes above the inputs and a mural painting above the courtyard passage
Initial situation
- Social housing from the 1950s
- 15 L-shaped buildings in a row, each with eight to twelve residential units (= a total of over 150 residential units)
- Building envelope uninsulated, in the course of the renovation, insulation at the upper and lower building closure (attic and basement ceiling)
- Heat supply via an outdated gas central heating system, heat distribution via radiators
15 heat pumps for 153 apartments
The apartments are at very different stages of renovation, as renovation work is only carried out when there is a change of tenant in an apartment.
In order to meet these changing heat demands and to heat as efficiently as possible, a bivalent system was chosen for the Hardenbergblock:
Each of the 15 individual buildings in the row, each with eight to twelve apartments, is heated by its own air-to-water heat pump. A modern gas condensing boiler, controlled by the heat pump, acts as a backup for peak loads. The heating stations are located on the top floor, and in the last six buildings on Goethestrasse they are located in the basement.
Requirement
- Climate-friendly and sustainable heat supply
- Quiet noise level, as the heat pumps are installed in the middle of the residential area in an open space in front of the buildings
- Renovation while residents are living in the building – restrictions for residents should be as minimal as possible
- Different spatial requirements for the heating stations: in some houses on the top floor, in some in the basement
- Eligible overall concept
The solution
Climate-neutral heating – with heat pumps in existing buildings
With the old heating system, the gas consumption for the entire building complex was well over one million kilowatt hours per year.
For Silke Eber, chair of the building cooperative, it is about ‘creating opportunities to move an old building like the Hardenbergblock – by far our largest property – in the right direction in terms of energy’. She emphasises: ‘This is unquestionably an important project for the future.’
Installation and operation
- 15 highly efficient Dimplex LA 35TBS: each building (with eight to twelve residential units each) is heated by a heat pump
- Installation in several stages: initially three buildings will be connected in December 2023, with further heat pumps being installed successively, planned completion August/September 2024
- Particularly quiet operation due to flow-optimised, tapered casing, additionally equipped with weather protection hood
- Installation on concrete foundations directly in front of the buildings
- Modern gas condensing boiler, controlled by the heat pump, acts as a backup for peak loads
- Intelligent control via heat pump manager
The decision was made to use sound-optimised units that meet all sound requirements despite their high performance. The installation location was also carefully selected: the air-to-water heat pumps are located at a distance from each other on the large open space in front of the building, so that the residents of the 153 apartments are not disturbed by noise.