Conventionally, heat source equipment for low-temperature processes in the industrial field has used propane (R290) and ammonia (R717, NH3), but they place a heavy burden on customers for safe operation due to their flammability and toxicity. Therefore, alternative products with low environmental impact are being demanded. Currently, the move toward terminating the use of HFCs is being accelerated with the agreement of countries around the world, such as the adoption of the Kigali Amendment to the Montreal Protocol. In the air conditioning field, R1234ze(E), which has low toxicity and a GWP (Global Warming Potential) of 1 or less, has been used for centrifugal chillers used as heat source equipment for large-scale facilities. To expand the application range of low-GWP refrigerants in the industrial field, we have established a technology for the multi-stage compression refrigeration cycle using R1234ze(E) that enables the supply of -20°C or lower-temperature brine and 60°C hot water. This technology can also be used for heating tower applications.
