GL2012 highlights: compact CO2 air-heating heat pump for industrial drying

Researchers in Japan studied and developed a small capacity CO2 heat pump for industrial drying that is hoped will reduce power consumption to about one third.
Compact electric heaters used in industrial drying processes often consume considerable amounts of electricity.
During the 10th IIR Gustav Lorentzen Conference on Natural Refrigerants which held in Delft, The Netherlands in June 2012, researchers from the Central Research Institute of Electric Power Industry (CRIEPI), in Kanagawa, Japan, presented the results of a study on a small capacity CO2 heat pump for industrial drying that is hoped will reduce power consumption to about one third of that of a conventional process.
CO2 was selected as it is a natural working fluid and is suitable for high-temperature difference heating. A cycle analysis, a preliminary heat-exchanger investigation and experimental and tests on prototypes showed that the breadboard air-heating heat pump could heat air from 25-80 °C with a 6 kW capacity and a COP of over 4, while the prototype air-heating heat pump (AHHP) achieved similar results with a 2.2 kW capacity and a COP of 3.5 under similar conditions.
The system is compatible with the Japanese ECO CUTE standard and 25-33% energy savings are expected for this system ; however, for commercial purposes it should be produced in bulk in order to reduce initial costs and applicable fields and clients have yet to be found.

Development of a Compact CO2 Heat Pump for Industrial Drying, Katsumi Hashimoto et al;

(paper downloadable in Fridoc database)