New CO2 gas cooler for dry and wet operation.

The use of CO2 as working fluid is now a well-established reality in the refrigeration industry, Air cooled CO2 gas coolers have to ensure high performance both in sub-critical as well as in transcritical operation. The gas cooler outlet temperature is a key parameter for a high-efficiency CO2 cycle. However, when the ambient temperature is high the traditional dry products start to give an outlet temperature which is too warm for efficient operation. To limit these drawbacks, LU-VE has developed an innovative solution named EMERITUS. This technology has an air-cooled exchanger on which two additional water cooling systems are used in sequence: treated water is sprayed onto the heat exchanger coil and the remaining non-evaporated water is collected and used on an adiabatic panel. This combination of the two techniques has positive effects on both the thermal capacity exchanged and the quantity of water consumed. The article describes the functional principle of the new product and its important beneficial effect on the performance of the CO2 plant, illustrating a case study in which the running costs of a plant equipped with the new product are compared with the running costs of a traditional solution.