Sustainable heat for an apartment house in Geneva
In densely populated urban residential areas, the switch from oil or gas to a sustainable heating solution presents special challenges. In the case of this apartment house with 49 homes in Geneva, it was possible to coordinate noise protection, installation and operation perfectly.
When standard solutions are no longer enough
To achieve the 2050 climate targets, many residential and office buildings will need to replace their oil and gas heating systems. This is where standard solutions often reach their limits, as demonstrated by this project in Geneva: For this apartment house with 49 homes, the close proximity to neighbouring properties placed stringent requirements on the roof design and called for the quietest possible solution. Under a heat contracting arrangement, Services Industriels de Genève (SIG) was responsible for renewing the heating and hot water systems and opted for heat pumps in the basement and low-noise air coolers on the roof.Coordinated heat generators
Two custom CTAexklusiv air/water heat pumps, each with an output of 190 kW, were installed in the existing boiler room. The redundantly configured units supply hot water at temperatures of up to 50 °C to the heating circuit buffer tanks and a booster heat pump. This water/water heat pump with an output of 113 kW increases the temperature to the 70 °C required for hot water heating. At the same time, it feeds a tank which provides heat for the controlled and efficient defrosting of the air cooler – a key issue for buildings close to bodies of water, where the air humidity is often higher.
The heat pumps on site
Two CTAexklusiv air/water heat pumps, indoor setup, 190 kW heat output each, COP 3.01 (A5/W50)
One water/water standard heat pump (booster), 113 kW heat output, COP 5.34 (W43/W65)
External air cooler on the roof: 30 dB(A) at 10 m
A quiet solution for the roof
CTA proposed eight smaller air coolers instead of two or three large ones. This made it possible to meet the requirements for a harmonious overall design and the quietest possible operation. The air coolers run under partial load most of the time, which also contributes to the low noise levels. This means that the fan speed can be reduced, which significantly lowers the noise emissions.Crucial interplay
CTA did not just provide the heat pumps and air cooler, but also planned out the controls for the entire system. Pumps, valves, tanks, air coolers and defrosting processes are managed in a coordinated manner. The basis for this is the standardised CTA control system, which can be adapted flexibly to project-specific requirements. This flexibility is crucial, particularly for systems whose behaviour is highly dependent on the location and operating conditions.Technology that works with the project
The project in Geneva shows what is involved in challenging renovations of large residential buildings. The heat pump alone is not decisive. What is needed are solutions that are tailored to the specific situation and take into account the surroundings, quiet operation, precise controls and clever integration of further components. This is where CTA’s strengths lie – in solutions that are technically sophisticated and can be adapted to structural considerations, the needs of residents and neighbours, as well as the requirements for reliable operation.
Kevin Dujardin,Technical Sales Consultant, CTAexklusiv
A successful solution
“I am especially proud that our team has been able to implement a solution that meets the high noise protection and aesthetic requirements, as well as the expectations for efficiency and sustainability.”
Contributors
Contracting: Services Industriels de Genève (SIG)
Installer: Durlemann Energies SA
Design: Energys Sàrl
Heat pump and system supplier: CTA AG
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