Sustainable energy supply for historic building

Capturing CO2 equivalent to 120,000 trees

Many may still remember: When driving past the factory A1, motorists often met with a waft of spices. The former premises of the legendary, world-famous company Maggi now houses 138 businesses. The historic industrial park “The Valley” will soon be sustainably heated and cooled using the ambient air. Boasting a total heating capacity of 2.2 MW and 2.7 MW cooling capacity, the four reversible chillers were installed in June 2023 and will supply the park with the requisite heating and cooling from October 2023. During its 30-year service life, the new energy system will save more than 44,000 tons of CO2, equivalent to the capturing and storing power of around 120,000 trees. 

Intelligent control of demand-driven power generation 

The four air/water heat pumps output between 170 and 550 kW of power each and are equipped with four output-regulated reciprocating compressors. The cooling circuits are filled with the natural refrigerant R-290 (propane). CTA is playing an important role in this project: Not only is it responsible for regulating the heat pumps’ cooling circuits, it also provides a control system for the entire plant. CTA thus controls all heat pumps, recoolers, and hydraulic components to ensure the correct heating and cooling output for this historic factory site.  

Environmentally friendly and safe 

The chillers’ cooling circuits are filled with the natural and sustainable refrigerant R-290. It has an extremely low global warming potential (GWP) value of three. However, propane does present one challenge: It is flammable. Cooling systems using propane as a refrigerant must therefore meet higher safety requirements. This challenge was met by installing and wiring the requisite safety features in the factory and by mounting, insulating and wiring most of the hydraulic components in the chiller housing prior to delivery. 

Roof size limitations 

Installing the four reversible chillers on the roof enabled expensive building space to be rented out and thus be put to better use. However, the available roof size is limited. Boundaries and maximum component sizes were known from the design phase. Accurately designing and engineering the system components was the key to success right from the start. 

Contributors

• Energy provider: EKZ, Zurich

• Site developers and property owners: Mettler2Invest, St. Gallen

• Planning/design: EKZ and CTA

• Installation: pietrobon hvac gmbh (HVAC) / ETAVIS AG (el. inst.)

• Heat pumps and system supplier: CTA AG, Münsingen