PR2015

The Proceedings of the 36th AIVC Conference " Effective ventilation in high performance buildings", held in Madrid, Spain, 23-24 September 2015.

The Presentations at the 36th AIVC Conference " Effective ventilation in high performance buildings", held in Madrid, Spain, 23-24 September 2015.

The scientific literature often reports example of educational buildings with extremely poor ventilation performance. An in-field investigation for the environmental and energy assessment of a kindergarten in Milano, confirmed that operable windows were not operated when the average daily temperature dropped below 14 °C, jeopardizing indoor air quality and kids learning performance.

Ventilation air may be provided in buildings by means of natural or mechanical strategies. When a HVAC system is installed, thermal comfort and indoor air quality (IAQ) may be controlled with higher precision. However, especially between the 70s and the 90s, mechanical ventilation systems have been installed on formerly naturally ventilated buildings without providing any control for natural ventilation.

This paper presents different ventilation solutions for the retrofit in existing school building with a special focus on historic buildings. These building usually pose a major challenge for the integration of energy efficient ventilation systems, i.e. with heat recovery. For decentralized systems, the ductwork can be minimized by wall integrated heat recovery units, whereas for central systems, a horizontal air distribution in the attic combined with vertical ducts was found to be a possible solution for listed buildings.

In 2011, the Danish Energy Agency initiated a study into ventilation solutions for the retrofit of schools to identify the most promising technologies. The reason was an increasing awareness that the ability of school children to absorb, adapt and use knowledge was affected negatively by inadequate ventilation rates. This paper presents an output of this study. A method for evaluation of the ventilation systems is proposed. The method consists of three categories with a clear separation to create a scoring board that facilitates transparent and unbiased evaluation.

Studies show that environmental conditions in schools are often inadequate, even in developed countries, and that they are frequently much worse than in office buildings. Outdoor air supply rates in schools are considerably lower than in offices, in many cases even lower than those observed in dwellings.

In an extensive simulation study using a multi-zone airflow and contaminant transport calculation software (CONTAM) recommendations for the supply air rates for residential housing were derived as input for the revision of the Austrian standard ÖNORM H 6038 (2014). The floor plan, the occupancy and the contaminant and humidity sources are modelled to represent a typical Austrian housing situation. A humidity buffering model is also implemented. Based on common thresholds for CO2, relative humidity (r.h.) and TVOC the so-called relative threshold deviation is determined.

Mechanical ventilation performance is a key issue related both to energy efficiency and indoor air quality. There are several techniques for measuring ventilation rates in buildings, such as blower boor tests, flow hoods, VAV box measurements and tracer-gas techniques. From several decades ago, tracer-gas techniques are recognized as the most widely employed method to estimate air exchange rate in buildings. These methods are based on the study of the temporal evolution of the concentration of an injected gas.

Airborne particles released from surgical team members are major sources of surgical site infections (SSIs). To reduce SSI risk, ultraclean-zoned ventilation (UZV) systems have been widely applied, supplementary to the main operating theatre (OT) ventilation. Usually, OT ventilation performance is determined without considering the influence of staff-member posture and movements. Whether the surgeon’s posture during surgery influences particle distribution within the surgical area is not well analysed and documented.