Untitled document


Development of a high-effectiveness air-to-air heat recovery heat exchanger for residential sector

Contacts : S.Gendebien,S.Bertagnolio,V.Lemort, P.Ngendakumana 


About 40% of the total energy use in Europe is due to buildings. An important part of this energy consumption is related to heating of residential buildings. In this sector, the first retrofit option to be envisaged for existing buildings is the improvement of the building envelope (insulation). However, a better insulation (and air tightness) generally imposes a better ventilation. 

The Green+ project has been launched in 2009. A large consortium regrouping companies and research centers has been set up to develop an integrated high-effectiveness recovery heat exchanger dedicated to the residential sector. The principle of such systems is very simple: viciated air, extracted from the building, is used to pre-heat (in winter) or cool (in summer) the fresh air flow rate coming from the outdoor environment. The project focuses on wall or window-frame mounted heat exchangers.


The aim of this project is to develop a new recovery heat exchanger dedicated to the residential sector.

Specific goals:

  • High effectiveness heat exchanger
  • Improved indoor air quality (IAQ) in residential buildings
  • Better comfort for occupants and better control of energy consumption

Test rig

The Thermodynamics Laboratory of University of Liège is involved at two levels in this project:

  • development of a simulation model based on the physical characteristics of the heat exchanger
  • design and use of a test rig allowing the assessment of the thermal  performances of the heat exchanger in various conditions

Test rig - Air temperature, pressure and flow rate measurements

Test rig

Participating countries and organizations

  • Greencom Development sprl
  • ACTE sa
  • SIRRIS Wallonie
  • ULG (laboratoire microsystème)
  • Microsys sa
  • ULG (Laboratoire de Thermodynamique)
  • ULG (Département des Sciences et Gestion de l'Environnement)
  • WOW Company sa
  • CECOPETE asbl



Vincent LEMORT

Laboratoire de Thermodynamique
Université de Liège
Campus du Sart-Tilman, bât B49
Chemin des Chevreuils
B-4000 Liège

Tel: +32 43 66 48 01
Tel: (Secretariat) +32 43 66 48 00
Fax: +32 43 66 48 12


This work is financially supported by the Walloon Region of Belgium. 









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