R290 (Propane) as refrigerant - Skadec GmbH (2024)

Questions and answers about Propan R290

What are the practical/regulatory limits of use or additional measures required for R290? (e.g. for 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 inlet temperatures above 20°C. The well-known compressor manufacturers limit the maximum evaporation temperature to 10°C or 15°C. Efficient operation of the system is therefore not possible at high system temperatures.
As with NH3, the additional measures required for R290 depend very much on the filling quantity and the installation location of the system (see question 10). There are only minor regulatory limits for outdoor systems.

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/water heat pump (also in the high output range), or when used in a chiller/cold brine unit for comfort air conditioning, industrial process cooling, refrigerated goods storage, machine cooling and food refrigeration. Generally in cooling mode for all applications that require a system flow temperature between -40°C and +20°C. Propene is more suitable for applications below -15°C. In heating mode for heat pumps, which then work efficiently even at very low ambient temperatures, with a flow temperature of up to 65°C over the entire application range.

For which technical performance ranges is R290 particularly suitable? (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 generate over 500 kW of cooling capacity individually. An air-cooled chiller with two screw compressors can achieve a cooling capacity of up to 1.2 MW.

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
Cost-effective in terms of service and operating costs
Low final compression temperatures -> low evaporation with single-stage system
Small filling quantity due to good density/evaporation heat ratio
Good material compatibility
Good pressure level
Not hazardous to water

Disadvantages:

Flammable

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 designed machine room in the building. The requirements are largely determined by the refrigerant charge of the system. The maximum refrigerant charge quantities result from the classification of the installation site, the category of the access area and the flammability class of the refrigerant (see DIN EN 378, 2018, Table C2). In most cases, there is no limit to the charge quantity. The background to this is the cooling capacity required by the customer and the resulting minimum refrigerant charge for the chiller.

Requirements for outdoor installation:

Category C access area to which only authorized persons have access. Practical example: Enclosed systems, roof installation, locked machine room. (Category C see DIN EN 378-1, 2018, 5.1)
Installation location category III in the machine room or outdoors. The classification of the refrigeration systems must also be observed. This can influence the classification of the installation location. 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 of DIN EN 378-3, 2016, 4.2 apply. Particular care must be taken here to ensure that no refrigerant can enter the building through a leak or otherwise endanger persons or property. As propane is heavier than air, attention should be paid to lowering the inlets when selecting the installation location. This is where escaping gas could accumulate. 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/instructions as a refrigeration 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, among others, should also be considered:

In order to achieve the classification installation location 3, the requirements of DIN EN 378-3, 2016, 4.3 apply to machine rooms. These apply to all machine rooms 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.
For refrigerants of groups A2L, A2, A3, B2L, B2 and B3, machine rooms 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 in accordance with the requirements of EN 60079-10-1. As a rule, 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 refrigeration machine is required.