The retrofit of existing ventilation and air treatment units : an experimental and methodological approach

Recent studies in Switzerland showed that in large non residential buildings, which can be compared for typology and ventilation needs, the consumption of electricity for mechanical ventilation can vary considerably from case to case. Moreover in such a building it represents a percentage not negligible of the whole consumption of electricity. We had a confirmation of that behaviour with a study we made during 1999-2000 on a set of eighty air treatment units of the Civic Hospital in Lugano (Southern Switzerland). In the case in point the consumption for the electrical engines for switching on the fans came to 15% of the whole consumption of electricity (this figure does not include the electricity consumption for the air treatment -post heating, humidification, etc.-). The analysis pointed out high possibilities of energy savings (40-60%) for many air treatment units both by the mean of simple and cheap measures of retrofitting of the plants, and thanks to a review of the ventilation needs in each interested room. In some cases it was possible to implement the proposed solutions and confirm, within experimental error and according to control measurements, the effective improvement estimated on paper.