HVACO2 – Air handling unit with reversible CO2 heat pump

Christian  Heerup

Your Contact

Contact me

Indtast venligst et validt navn
Or your phone number
Thank you for your message
Vi beklager

På grund af en teknisk fejl kan din henvendelse desværre ikke modtages i øjeblikket. Du er velkommen til at skrive en mail til Send e-mail eller ringe til +45 72 20 25 28.


HVACO2 – Air handling unit with reversible CO2 heat pump

Project start August 2021. Expected completion date September 2024.

Purpose of project
Heating and cooling for residential buildings, the service sector, and the industry account for 50 % of the primary energy supply in EU making it an important focus area in order to reach the goal of a 70 % CO2 reduction in Denmark in 2030.

The HVACO2 project aims to develop a new energy efficient air handling unit with heat recovery and reversible heat pump technology using the natural refrigerant CO2 for the HVAC market. Today, only a few HVAC solutions with natural refrigerants are available in the market despite an increasing demand for sustainable solutions for the building stock.

The market for HVAC solutions is huge and air-conditioning alone is estimated to account for 10 % of the global electricity use. Therefore, the air handling unit with reversible heat pump using CO2 as refrigerant is expected to achieve significant market shares contributing considerably to the phase out of fossil fuels.

Project objectives
The HVACO2 project will optimize the air handling unit by the development of a circuit design with ejector, benefitting the operation in warmer climates and thereby expanding the export potential. The project will develop new technology introduced in a model range with excellent performance enabling the lowering of the seasonal energy consumption for heating and cooling of the fresh air supply by approximately 25 % compared to the products available today.

The developed technology will be implemented in the production of ventilation units, which will be fitted individually to suit the customer's needs. The unit can provide heating, cooling, and ventilation in a tailor-made plug & play solution and will reduce the installation costs and increase the value for the customer.


The project is divided into the following phases:

  1. Functional requirements
  2. Test criteria and ecodesign
  3. Technical market barriers
  4. Design of HVACO2
  5. Construction of unit 1 and unit 2
  6. Functional test of air handling units
  7. Lab tests of HVACO2 unit at Danish Technological Institute
  8. Demonstration of HVACO2 unit at demonstration host
  9. Evaluation of performance.


  1. Danish Technological Institute (Project manager – Christian Heerup)
  2. Unic Air
  3. Carel Nordic
  4. DEAS
  5. Thermal Transfer Technology
  6. Dorin
  7. Shecco.

The project is funded by EUDP.