ROXSTAindustrial for TU Munich – CO₂ refrigeration for the new campus cafeteria in Garching
For the new cafeteria at the Garching research campus, a ROXSTAindustrial CO₂ system was installed—featuring blast freezing, heat recovery, and Wurm control technology. A flagship project for energy efficiency in university catering.
After almost 40 years, the cafeteria at the Garching campus had long exceeded its intended lifespan in terms of both building and equipment. Today, around 17,000 students and 7,000 staff come to the campus daily – and it continues to grow year after year. To supply the largest campus of the Technical University of Munich (TUM), a new building was constructed with an investment of around €44.5 million by the Free State of Bavaria.
A modern cafeteria for thousands of guests
Spacious, fresh cuisine, and sustainable CO₂ technology
With a usable floor area of 5,300 m², the new cafeteria is designed to serve approximately 7,300 meals and host 5,400 guests per day. The dining hall alone measures 2,200 m² and provides 1,500 seats. Since September 11, 2019, students have been able to enjoy a wide variety of fresh options: salad bars, a vegetable station, soup station, pizza, pasta and wok counters, a grill, as well as vegetarian and vegan dishes. All meals are freshly prepared, cooked, and served daily by the cafeteria team.
“With this new building, the Garching cafeteria will also be brought up to the latest technical standards. The university catering service of the Munich Student Union is delighted to operate this modern facility and to offer its guests high-quality meals in a stylish and contemporary setting,” says Dr. Ursula Wurzer-Faßnacht (Managing Director of the Munich Student Union).
The modernization of the Garching cafeteria was urgently needed, as the old building no longer met requirements in terms of capacity, technology, or energy efficiency. Thanks to cutting-edge systems, the new cafeteria consumes significantly less energy while also providing a long-term, sustainable, and future-proof refrigeration supply – using natural refrigerant CO₂.
The refrigeration system was designed by the engineering office Schmid+Partner in Erlangen and installed by K.E.D. Kälte- & Klimatechnik GmbH from Bischofsmais. Since 2022, the 40 kW limit has applied to synthetic refrigerants, which made it immediately clear to Hendrik Schmid (Schmid+Partner) that only a CO₂-based refrigeration system would be suitable for this application.
“After receiving the tender from Schmid+Partner, we submitted a proposal with a ROXSTAsmart from TEKO – and were awarded the contract. The only challenge was implementing the blast freezers. Plug-and-play quick coolers of this capacity simply don’t exist.”
Seamless installation despite large-scale equipment and limited space
Modular CO₂ system lifted in by crane and installed space-efficiently inside the building
The installation work was completed in record time and finalized in November 2018. With a total contract value of €1 million, the project ranks among the largest individual undertakings by K.E.D.
The 5,300 m² facility required extensive piping. In total, 1,750 meters of K65 piping (up to 1 5/8 inch in diameter) and approximately 18.5 kilometers of electrical cabling were installed.
Bringing the refrigeration system into the building also posed significant challenges. Using a mobile crane, the unit had to be lifted through a side opening in the façade into the second floor. From there, it was carefully transported about 30 meters through a ventilation center and stairwell to reach its final location.
Thanks to the modular design of the ROXSTA, the main unit and the medium-pressure station could be brought in separately – a huge advantage for a system of this size. And since the machine room offered only limited space, both units were installed independently, making optimal use of the available area.
Heat recovery
Waste heat put to smart use – CO₂ refrigeration system efficiently supports dishwashing technology
The waste heat from the refrigeration system is used to preheat the dishwashing water. Through an intermediate circuit with a pump, the heat is transferred to two 500-liter DK storage tanks equipped with an integrated legionella protection system. Depending on the retention time, the water inside the tanks is heated up to 80 °C. If the heat recovery system alone cannot reach the required temperature, the dishwashers provide additional heating.
This special heat recovery setup gave the planner the advantage of optimally combining the “refrigeration” and “dishwashing” systems.
For the electronic control system in the Garching cafeteria, K.E.D. relied on our partner Wurm Systeme from Remscheid.
“TEKO and Wurm have been working closely together for many years. That’s why we decided to build on this synergy and use Wurm’s proven FRIGOLINK solution,” says Michael Kraus. “In total, 8 main modules with 56 cooling point modules were installed. These manage medium- and low-temperature refrigeration as well as the blast freezers. For controlling the medium- and high-pressure valves, gas cooler regulation, heat recovery demand, and parallel compression, we use the jointly developed TEKO-Wurm CO₂ main module HCO₂ G4. Wurm control electronics are also used for CO₂ gas detection and remote data transmission.”
“The TEKO delivery package included a CO₂ gas cooler and 13 CO₂ flat evaporators from our WHITELINE brand. Since the cooling requirements of each room vary greatly, we supplied custom-designed evaporators tailored to the specific temperatures and room layouts. When designing the components, we always take the entire refrigeration system into account to provide our customers with a perfectly coordinated performance package.” – Dirk Niedenthal (Product Manager Heat Exchangers)
Good to know!
The blast freezers are used for rapid cooling of freshly cooked meals (Cook & Chill). This allows food to be gently reheated in other dining facilities of the Student Union while preserving the vitamins and nutritional value of the dishes.
Facility data
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300 m² usable area
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300 meals per day
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400 guests per day
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200 m² dining hall
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500 seats
Cafeteria equipment
Dedicated food storage rooms: dairy, meat, vegetables, etc.
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9 medium-temperature cold rooms – total area 185 m²
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4 freezer rooms – total area 105 m²
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36 small cooling units – display cases, wells, refrigerators, cooling tables
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4 blast chillers / shock freezers
ROXSTAindustrial
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Refrigerant: R744 (CO₂)
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Medium-temperature cooling:
- 5 x Bitzer compressors (1 with frequency inverter / incl. parallel compressor)
- 117 kW (t₀ -11 / tGK out 37 °C)
- Low-temperature cooling:
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6 x Bitzer compressors (1 with frequency inverter)
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13 kW (t₀ -32 / tC -11 °C)
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- Blast chillers / shock freezers (with frequency inverter): 4 x 12.4 kW (t₀ -25 °C)
Control system
Wurm control electronics FRIGOLINK: rack system, medium- & high-pressure valves, gas cooler regulation, heat recovery demand
Heat recovery
Max. capacity: 161 kW (water in/out 30/65 °C)
Special features
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Parallel compression
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Heat recovery
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Suction gas heat exchanger per suction pressure stage
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Frequency inverter per suction pressure stage (parallel compression, MT/LT)
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5 different LT suction pressure stages
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WHITELINE gas cooler with 6 EC fans: 310 kW (tLE 35 °C / tGK out 37 °C)
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13 x WHITELINE CO₂ flat evaporators
(1) Source: www.tum.de/nc/die-tum/aktuelles/pressemitteilungen/details/35678