Twin-slab air-cooled condenser

Bora air-cooled condensers received enhanced heat exchangers

This week Kaltra is launching air-cooled refrigerant condensers of the Bora VS series equipped with new, twin-slab microchannel heat exchangers operating with a counterflow of refrigerant and air and arranged in 4-coil V-banks. This innovative solution was successfully adopted earlier in the second generation of Lightstream air-cooled chillers.

New condensing coils deliver 20-25% more capacity with the same unit footprint and power consumption and provide excellent performance for Bora units at partial loads.

With an external coil slab acting as a subcooler, the higher degree of subcooling that improves the refrigerating effect and COP is achievable – without increasing compressors’ power draw. Along, the single-pass design of the coils ensures low pressure drops on the refrigerant side. The overall refrigeration effect is especially well reflected with the use of HFO refrigerants and other refrigerants with the small latent heat of vaporization.

Condensers equipped with twin-slab coils (operating pressure of as high as 45bar) are suitable for a wide selection of refrigerants: HFCs and HFO blends and natural refrigerants like propane (R290) and ammonia (R717).

Depending on project goals, customers may convert twin-slab condenser advantage into various tangible benefits:

  • Increase in condenser heat rejection
  • Reduce noise power without capacity losses
  • Improve the refrigeration system efficiency (COP)
  • Lower the initial system cost

The range includes V-shaped condenser models with 800mm and 910mm axial fans with AC or EC motors, heat rejection from 50 to 380kW (R404a, 30°C inlet air, and condensing temperature of 45°C).

Later this year, the same 4-coil V-banks will be adopted for Ultracompact-V II series air-cooled chillers in the capacity range of 50-275kW.

Headquartered in Germany and Austria, Kaltra designs, develops, and manufactures air conditioning and refrigeration equipment and systems. The company offers air-cooled, water-cooled, and free cooling chillersprecision air conditionersIT cooling systems, including room-, rack- and row-based solutions, and energy management solutions. It also designs and manufactures air-cooled condensersdry coolers, and cooling units for special applications. Additionally, Kaltra offers microchannel heat exchangers for condenser, evaporator, and water cooling and heating applications, as well as aluminium coils for small cooling applications. All Kaltra products are engineered with the clear objective of improving energy efficiency and reducing total cost of ownership.

For more information on Kaltra and its products call +49 (0) 911 253 421 07 or visit