How can I make my own refrigerant

How to use propane as a refrigerant for commercial applications

From January 2018, the phase-down scenario of the F-gas regulation will bring about drastic changes for commercial refrigeration. Because the quota regulation will lead to an initial drastic shortage of common high-GWP refrigerants. Up to ten years from now, this GWP threshold will gradually decrease to values ​​that are expected to be well below 600. In addition, the following milestones have been set:

  • January 1, 2020: Prohibition of placing on the market commercial refrigerators and freezers (hermetically sealed devices) with GWP 2500
  • January 1, 2022: Ban on the placing on the market of commercial refrigerators and freezers (hermetically sealed devices) with GWP 150
  • January 1, 2025: The placing on the market of mono-split devices with a filling quantity of less than 3 kg F-gases with GWP 750 is prohibited

Rising prices for HFC refrigerants

But the year 2018 and the phase-down are already casting their shadows. A few months ago, various manufacturers reported to the market about upcoming price increases for HFC refrigerants and blends as well as a planned sales stop of R404A and R507C at the end of the year. The specialist press then revealed that the refrigeration and air conditioning wholesalers have now passed on the prices, some of which have risen in the double-digit percentage range, to the refrigeration plant construction industry. This means that margins are melting or the operator is held accountable. At the same time, price increases and discontinuations are gradually paving the way for environmentally friendly solutions, including natural refrigerants. One of them is the hydrocarbon propane (R290).

Applications of propane

If you look at the diverse uses of hydrocarbons, their flammability properties are put into perspective. On the contrary, it is precisely this property that makes propane or isobutane interesting for gastronomy, the leisure industry or for heating purposes. Liquid or town gas as well as gas bottles supply gas stoves, condensing boilers, grills or radiant heaters in close proximity to people. Nobody cares about explosion hazards.

It is different in refrigeration technology. There R290 is classified in security group A3. This means that it is less toxic, but has a higher flammability. If you take these properties into account and adhere to precautionary measures and maintenance intervals, propane can be used as a refrigerant in many refrigeration systems in the future.

The new tamper or piggyback units from Rivacold for wall and ceiling mounting are an example of this. Various smaller applications for commercial normal and deep freezing up to 3 kW of cooling capacity can be equipped with these refrigeration systems. The heat is dissipated via an air-loaded condenser or a connected water circuit. The units are produced in accordance with the Machinery Directive 2006/42 / CE and the current DIN EN 378-2. According to TRBS 2152-2, the cooling circuit is classified as "technically permanently tight". In addition, an additional fan was provided in the compressor room, which in the water-cooled units operates continuously and in the air-cooled units only when the condenser fan is not running. This avoids an explosive atmosphere in the event of a leak. All electrical components are designed in such a way that no ignition sparks can occur. In addition, the fact that there is no contact with the refrigerant ensures double safety.

Safe atmosphere

The filling quantities of the units per refrigeration circuit are below 150 g. As a result, according to DIN EN 378, no special features need to be taken into account for the installation conditions if a free volume> 4 m in a cold room or the installation area of ​​a unit3 is available. The reason: The lowest flammability concentration for R290 is 38 g / m3. With the maximum filling quantity per cooling circuit of 150 g, an explosive atmosphere cannot arise at any time. In the case of indoor installation, which is often the case, an optical or acoustic warning system is recommended for preventive safety, which is activated from a threshold value of eleven percent LFL (Lower Flammability Level). In addition, an emergency ventilation system can be provided that is activated in the event of a gas alarm. In principle, however, sources of ignition in the vicinity of the units or in cold rooms are to be avoided.

If the system manufacturer observes these instructions in his risk analysis, then from the operator's point of view there is multiple security when using the refrigerant propane for a number of applications in commercial cooling.

This post by Lorenzo Milano first appeared in the 9/2017 issue of Die Kälte & Klimatechnik. The author is Rivacold Product Manager at Cool Italia GmbH, Fellbach.