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Future-proof air coolers

For natural and alternative refrigerants

With Walter Roller, you are already prepared for the future. Our range offers a variety of air coolers for safe operation with refrigerants of safety classes A2L and A3 (also applies to A1) or the natural refrigerant CO2 (R744).

The appliances can be used in normal and deep-freeze applications.

A2L/A3 (can also be used with A1)

Adapted air coolers for low-hazard operation with flammable refrigerants. The future-proof air coolers can also be operated with A1 without any modifications. This means that the evaporator can be installed in a system that is currently operated with an A1 refrigerant and can continue to be used in the event of a future changeover to an A2L or A3 refrigerant.


Walter Roller MultiRef

Use with current and future (flammable) refrigerants

We are continuously converting our existing product portfolio of air coolers for A1 refrigerants to safe operation with flammable A2L/A3 refrigerants.

To simplify the overview for customers, our A2L/A3-capable evaporators will be listed under the MultiRef product line in future.

The previously available A2L/A3 variants for flammable refrigerants will remain technically the same - only the name will change.

The name MultiRef (multiple refrigerants) is the program for our new product series. It can be used for conventional refrigerants (A1) as well as for future flammable refrigerants (A2L/A3). The products can therefore already be used in A1-operated systems today without any problems and can continue to be operated with A2L/A3 in the future without technical modifications to the evaporator. This results in a high savings potential on the appliance side.

Our newly developed refrigerant labels with color coding provide a quick overview of which refrigerants our respective products are suitable for.

The color code can also be found in the logos of the respective product lines: H2OCooler has the blue square for water/brine.

These models are at your disposal for use with A1/A2L/A3

Available air coolers also with electric defrost (T-version)

Available air coolers without defrost heater, for circulating air defrosting

Why switch to alternative refrigerants?

As part of the global effort to address climate change, stricter regulations are coming into force that ban more and more synthetic refrigerants. The F-Gas Regulation in force in Europe provides for a stepwise reduction in CO2 equivalents for refrigerants by 2030. Alternative refrigerants that have a low GWP are gaining in importance.
These include natural refrigerants, such as CO2, propane, and NH3, and chemical refrigerants, such as hydrofluoroolefins (HFOs), which, unlike natural refrigerants, generally do not require major equipment design changes.
However, the alternative refrigerants often have the characteristic of being toxic or flammable.

Flammability - a controllable risk:

For the facility design, decision criteria are available to assess the risk for the operation.
First, the safety class for flammability and toxicity must be determined.
If flammable refrigerants are used, the design must then comply with the specifications of the Machinery Directive and DIN EN 378 (2018). Here, the installation conditions, charging quantities and room volumes are considered in a risk assessment.
Independently of this, any planning should also be assessed according to its energy efficiency, environmental compatibility and life cycle costs.

Refrigerant safety classification

The hazard classification of refrigerants is defined by the safety classes according to ISO 817, which classifies them according to both flammability and toxicity.
The letters provide information on toxicity, the following number on flammability.
The currently used HFO refrigerant R454C falls into class A2L and is thus classified as low flammability.


System components must be safe

The basis for the construction and operation of a refrigeration system designed in accordance with DIN EN 378 is the use of approved components.
With regard to the use of evaporators for refrigerants of safety classes A2L and A3, it must be ensured that there is no risk of ignition or explosion (e.g. in the event of a leak). A possible trigger could be the very high surface temperatures of the electric heating rods.
According to EN 378-2, the maximum surface temperature on a component that may be exposed to a flammable refrigerant in the event of a leakage must not exceed the self-ignition temperature of the permitted refrigerant minus 100 K.


Roller A2L/A3 air coolers already meet the high safety requirements for use with flammable refrigerants:

Darauf können Sie sich verlassen:

Modifications for low-hazard operation of air coolers

  • Special heating elements with reduced specific heat capacity
  • Revised defrosting concept for block and tray to maintain max. permitted surface temperatures
  • Optimized and tested heater placement for consistent defrost reliability
  • Improved grounding concept against electrostatic charging of the housing
  • Design tested for ignition sources and conforming to standards

    Highest material quality

    • Use of quality copper tubes mainly from German manufacturers
    • Core tubes made of copper Cu-DHP with strong walls
    • Heat exchanger block for operating pressures up to 80 bar with high pressure refrigerant CO2 (R744)

    Quality and pressure test

    • Manufacture according to Pressure Equipment Directive 2014/68/EU
    • Pressure and leak test of the devices for refrigerants: 27.5 bar overpressure
    • Pressure and leak test of the units for high pressure refrigerants: < 27.5 to 115 bar gauge pressure
    • All units are subjected to a precise quality outgoing inspection
    • Special pressure and leakage tests when using flammable refrigerants and CO2




      Corrosion protection more important than ever:

      When flammable refrigerants are used, the permanent tightness of all system components becomes even more important. For this reason, various types of corrosion protection are optionally available to withstand the chemical stresses caused by substances in the ambient air and subsequently prevent refrigerant loss.

      This is what we offer you:

      •  Consulting on optimum corrosion protection
      •  Variety of different corrosion protection options
      •  Various fin materials   
      • Tin-plated copper core tubes for increased reliability against corrosion


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      How can we help you?

      We consult you competently and comprehensively!

      Make a concrete enquiry now!

      Tel.: +49 (0) 7156 / 2001-29