German manufacturer Rheinmetall has developed a prototype propane (R290) e-compressor and heat pump module for electric vehicles (EVs), according to a presentation by Philipp Barth, the company’s Senior Manager of Product Engineering.

Testing conducted by Rheinmetall has shown that the compressor can provide 10kW (2.8TR) in cooling capacity, which is 40% higher than an R1234yf compressor of the same size.

Barth shared details of the company’s efforts during his presentation in the Transport and Mobile Air-Conditioning (MAC) Case Studies session at the ATMOsphere (ATMO) Europe Summit 2023. The conference took place September 19–20 in Brussels and was organized by ATMOsphere, publisher of Hydrocarbons21.com.

Light-weight and low charge

In addition to offering a higher cooling capacity, the compact design of Rheinmetall’s R290 compressor keeps the refrigerant charge, costs and unit weight low, explained Barth.

The company’s extensive testing of the compressor – around 2,250 hours – has proven its durability and performance over the longer term, he added.

As detailed in his presentation, the R290 compressor is used within the manufacturer’s heat pump module, which is also currently in the prototype phase. The module is connected to a waterloop as part of an indirect HVAC system. It contains 190g (6.7oz) of propane and weighs around 15.9kg (35.1lbs).

Rheinmetall is currently working to further develop both its R290 compressor and heat pump module to improve performance and make it more user friendly. Developments include enhancing its higher-pressure capabilities, eliminating piping and reducing refrigerant charge. It is also planning to add a control box for easier management for the customer, he said.

The company plans to have the product available on the market by 2028, he added.

Earlier in 2023, Rheinmetall announced that it had won a €770 million (US$841 million) long-term supply contract of R290-based compressors. Industry sources said that the compressors are for a manufacturer of domestic heat pumps.

According to the Rheinmetall, it was chosen due to the “outstanding key performance data and long service life” of its compressor and for its use of propane.