Mechanical ventilation with heat recovery in cold climates

Jesper Kragh, Jørgen Rose, Svend Svendsen

    Research output: Chapter in Book/Report/Conference proceedingArticle in proceedingsResearchpeer-review


    Building ventilation is necessary to achieve a healthy and comfortable indoor environment, but as energy prices continue to rise it is necessary to reduce the energy consumption. Using mechanical ventilation with heat recovery reduces the ventilation heat loss significantly, but in cold climates like the Northern Europe or in arctic climate like in Greenland or Alaska these ventilation systems will typically face problems with ice formation in the heat exchanger. When the warm humid room air comes in contact with the cold surfaces inside the exchanger (cooled by the outside air), the moisture freezes to ice. The analysis of measurements from existing ventilation systems with heat recovery used in single-family houses in Denmark and a test of a standard heat recovery unit in the laboratory have clearly shown that this problem occurs when the outdoor temperature gets below approximately –5ºC. Due to the ice problem mechanical ventilation systems with heat recovery are often installed with an extra preheating system reducing the energy saving potential significantly. New designs of high efficient heat recovery units capable of continuously defrosting the ice without using extra energy consumption are therefore suggested in this paper for future work.
    Original languageEnglish
    Title of host publicationProceedings of the 7th Symposium on Building Physics in the Nordic Countries
    Number of pages1214
    VolumeBind 2
    Place of PublicationReykjavik
    PublisherOddi hf
    Publication date2005
    ISBN (Print)9979-9174-5-8
    Publication statusPublished - 2005
    Event7th Nordic Symposium on Building Physics - Reykjavik, Iceland
    Duration: 13 Jun 200515 Jun 2005
    Conference number: 7


    Conference7th Nordic Symposium on Building Physics
    Internet address


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