The Studierendenwerk Karlsruhe operates a unique refrigeration system
The first LNG plant in the world, which works through the manufacture of an ice cold medium with the most environmentally friendly propane, R290.

90 refrigeration places, refrigeration rooms, showcases, and refrigerators and condensers of the CO2 PBXs, will supply a 3 km comprehensive pipe network with liquid cooling agents.

This coolant consists of an ecological and technical food-safe mixture of water and about 8% ethanol with an ice fraction of about 25%. Thus, climate damaging gases are omitted entirely, ensuring that the system already meets statutory policies that will apply starting in 2022. According to the EU-F-Gas regulation, refrigerants with climate-damaging effects will not be authorized starting in 2022.

In the heart of the system there are 6 ice machines, each with 14 kW cooling capacity, which produce ice in night mode. By decoupling the ice production and removal, high-priced power peaks are also avoided, and the operation of renewable facilities is facilitated. In a 40 m3 Tank, the ice slurry is saved until removal day. The lower outside air temperatures and the thus lowered condensation temperatures enable energy savings of 20-30%.


Construction period: 2012-2013
Commissioning: 2013

Basis: Combination of liquid ice, propane and CO2
Liquid ice: 25% ice, 75% liquid (water with approx. 8% ethanol)
Production: 6 ice generators with 14 kW refrigerating capacity each
Distribution: 3km Rohrnetz zu 90 Abnahmestellen
Propangas: natural refrigerant R290 for the normal refrigeration
CO2: transforms the temperature of the liquid ice from -3,5°C to -25°C
Tank volume: total of 40m³
Investment: approx. 1 Mio. Euro

Scientific support: Prof. Dr. Michael Kauffeld,
University of Applied Sciences
Planning: Engineering office Günther Schmidt, Hochheim
Implementation: Hafner-Muschler, Balingen / IBV, Tiefenbach
Funding: Ministry of Science, Research and the Arts/
Baden-Württemberg State Office of Property and Construction