Alfa Laval is expanding its comprehensive programme of air heat exchangers with a range of CO2 gas coolers. These replace traditional air-cooled condensers in refrigeration systems where CO2 is used as a single refrigerant. The design of the new gas coolers is based on the well-proven and popular Alfa Laval axial condensers, AlfaBlue Junior, AlfaBlue and AlfaV. However, the new gas coolers have a design pressure of 120 bar and are fully optimized for CO2 systems and conditions.

In recent years Alfa Laval has focused on developing products that enable the transition from synthetic refrigerants with negative environmental impact to sustainable, energy efficient solutions utilizing natural, climate-neutral refrigerants. Of these, CO2, with its low global warming potential (GWP) and capability to recover heat at high temperature, is outstanding.

The behaviour of CO2 as a refrigerant in cooling installations is governed by the required operating conditions. At temperatures above 31°C (CO2 critical point), this refrigerant does not behave in the same way as a traditional two-phase condensing fluid – turning from a superheated vapour into a sub cooled fluid – but remains in a pseudo gaseous phase.

Thus, the traditional air-cooled condenser, the system component used to condense superheated refrigerant vapour into a sub cooled fluid, becomes a “gas cooler”.

“The fact that CO2 acts significantly differently from traditional refrigerants, such as HCF and ammonia, has had a large number of design and production implications for the new product range,” explains Paolo Dalle Pezze, Product Portfolio Manager, Alfa Laval.

“These include design parameters, such as coil and circuiting design, tube thickness, connections and all kinds of pressure issues. In order to deal with these high pressures, we have made a substantial investment in our Italian production site at Alonte where we have set up a special reinforced pressure testing facility.”

According to Paolo Dalle Pezze, a wide range of options will be available to fulfil market demands. “Our gas cooler configurations using EC motors are particularly worth mentioning. They are the best choice available for our customers in terms of energy savings and environmentally friendly operation”.

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