GERMANY: Bitzer has announced the development of a subcooling unit capable of boosting the efficiency of  both new and retrofit transcritical CO2 systems in warm climates.

At an ambient temperature of 32°C, the Expander is said to increase a standard booster system’s cooling capacity at the design point by more than 20%. Bitzer maintains that, in seasonal terms, for example, energy savings of up to 17% are possible in a parallel system in warm climates.

The Expander unit works much like traditional external subcoolers. The internal subcooling unit comprises a control valve, a heat exchanger and the heart of the system: a linear expander-compressor unit. The Expander unit relaxes the primary mass flow, whilst the energy generated in the same unit compresses the subcooler mass flow and feeds it back before the gas cooler – without any additional electrical energy. Thanks to the compact dimensions and simple mounting behind the gas cooler, installation is said to be quite simple with no need to redesign the refrigeration system.  

Bitzer has been working with discount supermarket Aldi Süd in the development of the Expander. Testing will be carried out in a number of its stores.