DX coil cools the air by transferring the heat taken from the air passing through theevaporator to refrigerant with the help of compressor. To simply describe the system,a direct expansion cooling coil is adapted to an air handling unit and required numberof VRF outdoor needed by this coil is connected. While performing this operation, therefrigerant is evaporated at the source (AHU) where the heat transfer is made.During the heat transfer by conventional cooling groups (chiller / hot water boiler),heat is transferred to water first and then the heat transfer is done inside the AHU viapipes and pumps. AHU with DX coil provides air conditioning in the place withoutneed for hot water boilers thanks to its traditional cooling groups and heatpumpoperation feature.


  • Energy losses in refrigerant pipes are much less.
  • With high COP values, it is very advantageous in terms of running and investment costs.
  • Heating and cooling is performed only by VRF outdoor unit.
  • With a single device, air flow of 1.8 – 25 m³/h and power of 14-180 Kw/h.
  • Optimum control with the compressors with variable capacity (inverter technology) and fans used.
  • Ability to give quick response to the partial loads.
  • Taking into regime in a very short time.
  • Unlike the traditional AHU system water coil there is no freezing risks in this system.
  • Maintenance costs are much lower than the traditional systems.
  • Low noise level.
  • A new, convenient and quick solution for small and medium size facilities by a single investment.
  • This system impose much less static load to the building than the system with chiller and hot waterboiler.
  • It is not required to operate indoors as it is suitable for external environmental conditions.