The natural refrigerant R290

1. What are the practical or regulatory limits of use or additional measures required for R290? (e.g. with NH3 mechanical ventilation of the engine room depending on the filling quantity of the system)

• R290 is less suitable for processes with very high system flow temperatures above 20°C. The known compressor manufacturers limit the maximum evaporation temperature at 10°C or 15°C. An efficient operation of the plant is therefore not possible at high system temperatures.
• As with NH3, the necessary additional measures for R290 depend very much on the filling quantity and the installation location of the system (see question 10). For outdoor systems there are only minor regulatory limits.

2. For which applications is the refrigerant R290 particularly suitable?

R290 is very well suited as a refrigerant in heat pumps and chillers. For many cooling and heating applications in an air-to-water heat pump (also in a large capacity range), or when used in a chiller/chiller brine for comfort air conditioning, industrial process cooling, chilled goods storage, machine cooling and for food cooling. Generally in cooling mode for all applications that require a system flow temperature between -40C° and +20°C. For applications below -15°C propene is more suitable. In heating mode for heat pumps, which then operate efficiently even at very low ambient temperatures, with a flow temperature of up to 65°C over the entire range of applications.

3. For which technical performance ranges is R290 particularly well suited? (Where are the technical performance limits of R290?)

For the refrigerant R290, scroll compressors are already available for very small applications in the Watt capacity range. For the medium and large capacity range, there are reciprocating and screw compressors that can already individually generate over 500kW of refrigerating capacity. An air-cooled chiller with two screw compressors can thus achieve up to 1.2 MW cooling capacity.

4. What are the advantages and disadvantages of R290?

Advantages:

• Very low GWP (3), no ODP (0).
• Not affected by F-Gas regulation
• Future-proof, available and inexpensive refrigerant
• Low service and operating costs
• Low final compression temperatures -> deep evaporation with single stage system
• Small filling quantity due to good density/evaporation heat ratio
• Good material compatibility
• Good print position
• Not hazardous to water

Disadvantages:

• Combustible

5. What are the requirements for the machine room/installation site?

The requirements for an outdoor installation are significantly lower than those for an installation in a specially designated machine room in the building. The requirements result mainly from the refrigerant filling quantity of the installation. The maximum refrigerant filling quantities result from the classification of the installation site, category of the access area and flammability class of the refrigerant (see DIN EN 378, 2018, Table C2). In most cases, no limitation of the refrigerant charge quantity is intended. The background is the refrigerating capacity required by the customer and the resulting minimum refrigerant charge for the refrigerating machine.

Requirements for outdoor installation:

• Category C access area to which only authorized persons have access. Practical example: Fenced-in installations, roof installation, closed machine room. (Category C see DIN EN 378-1, 2018, 5.1)
• Installation site category III in the machine room or outdoors. In addition, the classification of the refrigeration systems must be observed. This can influence the classification of the installation site. Practical example: No limitation for outdoor installation in combination with an indirectly ventilated or double indirect system. (Class III see DIN EN 378-1, 2018, 5.3 and 5.4).
• For outdoor installation, the requirements according to DIN EN 378-3, 2016, 4.2 apply, where special care must be taken to ensure that no refrigerant can enter the building through a leakage or otherwise endanger persons or property. Since propane is heavier than air, attention should be paid to lowering the inlets when selecting the installation site. Any escaping gas could accumulate here. In addition, the system should be positioned so that sufficient fresh air can circulate around the refrigerant-carrying parts. The machine must also be marked with danger signs/indications as a refrigerating machine with flammable refrigerant. The machine must be placed at a sufficient distance from possible ignition sources.

Requirements for installation in machine rooms:

The same conditions apply as for outdoor installation and the following criteria should also be considered: 

• In order to achieve the classification of installation site 3, the requirements of DIN EN 378-3, 2016, 4.3 apply to machinery spaces. These apply to all machinery spaces regardless of the refrigerant. These include access restrictions (DIN EN 378-3, 2018, 5.1) as well as structural measures such as those in DIN EN 378-3, 2018, 5.12 Requirements for doors, walls and ducts.
• In the case of refrigerants of groups A2L, A2, A3, B2L, B2 and B3, machinery spaces must meet the requirements of DIN EN 378-3, 2018, 5.14 in addition to the general requirements. This means that the machine room must be assessed with regard to the flammability of the refrigerant and classified according to the requirements of EN 60079-10-1. This means that at least one emergency ventilation system in combination with gas detectors (see DIN EN 378-3, 2018, 9.3.2) and emergency shutdown of the refrigerating machine is required.

6. Which guidelines and standards are to be applied when handling R290?

• Relevant DIN EN 378;
• Technical rules for operational safety TRBS 2152;
• Leak tightness of refrigeration systems DIN EN ISO 14903;
• Pressure Equipment Directive DGRL2014/68/EU;
• Machinery Directives MRL 2006/42/EU

7. What training beyond the usual content is required to handle R290 or to build a refrigeration system with this refrigerant (e.g. welding certificate for NH3 system pipes)?

• Work must be carried out by competent personnel, in addition they should be trained in handling flammable refrigerants.
• The handling of A3 refrigerants is already an integral part of the training to become a mechatronics technician for refrigeration technology and the master craftsman training.
• A suitable training program is available from federal technical schools, competence centers or manufacturers.

8. How does the price of R290 refrigerant develop and how does availability develop?

As the GWP quota is further reduced, refrigerant manufacturers will increasingly rely on the production of low GWP and natural refrigerant in order to utilize their production capacity. In addition, R290 is not subject to a patent, so there will be no patent fees. Stronger demand could compensate for increased supply. The resulting assumption: price remains low or decreases.