The application of advanced propane facilities for fruit storage is rapidly gaining in importance. At the recent Fruchtwelt Bodensee in Friedrichshafen, the Kratschmayer, Kälte-Klima-Lüftung GmbH from Kupferzell encountered much enthusiasm for its propane cooling brine with self-developed storage software. The biggest advantage of the natural refrigerant propane (R290) instead of the usual ammonia, is almost complete plant security and it being an environmentally friendly application, according to the management.

In the fruit and vegetable storage area, propane is a good application as a coolant within a cooling installation with brine. The cooling installation, which contains the complete refrigeration circuit with compressor, condenser, expansion valve and evaporator, is located outside the building on a compact, weather-protected machine frame. The evaporator is designed as a plate heat exchanger. This enables the heat transfer via a carrier medium (brine). A water pump drives the cold water cycle. Motor-controlled ball valves can be used to regulate the cooling capacity of the individual air coolers in the storage rooms.

The propane cooling brine and heat pumps of Kratschmayer GmbH are special in that they are not affected by the forthcoming market regulations and successive bans on hydrofluorocarbons (HFCs). The installationn will also be operated with the environmentally friendly and natural refrigerant propane (R290) and as a result will not be subject to future tightening of the F-gas regulation. R290 is a natural refrigerant with good thermodynamic properties within the storage temperature ranges typically required for fruit and vegetables, and is characterized in particular by its good environmental properties.

As the biggest disadvantage of the use of propane, people often refer to its composition, which demands higher investment costs because of the flammability of the R290 refrigerant. However, the difference between the building and operating costs over the entire service life of such a cooling installation plant compared to that of a direct expansion plant diminish rapidly with the rising refrigerant prices in the future. The separation of refrigeration and cooling distribution drastically reduces the required refrigerant charge. The so-called brine cooling causes smaller temperature differences on the evaporator, which is accompanied by a lower dehumidification and thus leads to better product quality. The compressor type can remain smaller and energy-intensive defrosting cycles are eliminated because the product withdraws less water from the produce. Energy-saving defrosting can cover the remaining defrosting costs. In addition to this, the excess heat can be used for a heating installation or for domestic water heating with the use of a second plate heat exchanger.

Another selling point is the introduction of the Bafa support program until December 2019. With risk assessment and ZÜS acceptance, the risks of propane are reduced to a minimum. Here, better safety aspects relating to the smaller coolant quantities, the outdoor installation of the cooling unit and leakage monitoring by means of a gas sensor should be emphasized. The regulating process, specially developed by Kratschmayer on WAGO-basis, incorporates many years of experience in the fields of refrigeration and air conditioning technology.

The possibility of remote maintenance for inspection, early fault detection, analysis, optimization and troubleshooting can ensure that unnecessary machine shutdowns will be prevented. If a fault occurs, the system can continue to operate in an emergency mode. The consequences are improved efficiency and reduced system downtime. The regulating process includes a freely configurable data logger and a data plotter for recording and analyzing process data. The first evaluations were very positive, particularly because of the high level of installation security, said the management when questioned at their stand in Friedrichshafen.

The Kratschmayer Group offers complete solutions in the field of refrigeration, air conditioning, ventilation, heat and building automation. With the production of innovative cooling installations and heat pumps with the natural refrigerant propane (R290), the company has become the market leader in the realm of fruit storage in recent years. In the meantime, the Kratschmayer Group has six locations from which both national and international major customers are serviced. Since the company also cares about the training of future experts, in 2017 -after a thorough examination- the Handwerkskammer Heilbronn-Franken awarded it the title of Top Training Company of 2017.


For more information: Kratschmayer Kälte-Klima-Lüftung GmbH