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The test lecture rooms of KU Leuven Ghent Technology Campus are one the demonstration cases of IEA EBC Annex 62: Ventilative Cooling. This nZEB school building is realised on top of an existing university building and contains 2 large lecture rooms for maximum 80 students with a floor area of 140m² each. An all air system with balanced mechanical ventilation is installed for ventilation, heating and cooling.

Ventilative cooling (VC) is an application (distribution in time and space) of air flow rates to reduce cooling loads in spaces using outside air driven by natural, mechanical or hybrid ventilation strategies. VC reduces overheating in both existing and new buildings - being both a sustainable and energy efficient solution to improve indoor thermal comfort. VC is promising low energy cooling technology that has potential to substantially reduce the use of mechanical cooling in airtight and highly insulated buildings.

Even in Northern European climates, overheating in many Nearly Zero Energy Buildings is a barrier to year round occupant satisfaction with the indoor thermal environment. Improved energy performance and enhanced thermal comfort should not be perceived as a rigid dichotomy of concepts. However, an acceptable thermal environment, during extended cooling periods now present in NZEB’s, can come at a high energy cost if mechanical cooling is used.

Ventilative cooling (VC) is an application (distribution in time and space) of air flow rates to reduce cooling loads in spaces using outside air driven by natural, mechanical or hybrid ventilation strategies. Ventilative cooling reduces overheating in both existing and new buildings - being both a sustainable and energy efficient solution to improve indoor thermal comfort. In new buildings VC, may save cooling energy and thereby make it easier to fulfil future energy legislation for buildings.

Over the course of the four-year research project of the IEA EBC Annex 62, Ventilative Cooling (VC) has been proven a robust and highly energy efficient solution to support summer comfort in both residential and commercial buildings. Furthermore our findings show that VC can be successfully applied in both cool and warm temperate climates. 

Aeroseal technology utilizes air laden with fine aerosol particles (2-20 μm) to pressurize a duct system, resulting in deposition of those particles at the leaks within that duct system. By reducing leakages of duct systems by 90% in average Aeroseal sealing technology allows reducing leakages to a standard better as air tightness class D or ATC 1 for a complete system. Aeroseal technology can be applied in new constructions as well as in existing systems to improve energy efficiency, cleanliness of ventilation systems, IAQ and comfort.

The implementation of the Energy Performance of Buildings Directive 2010/31/EU recast puts increasing pressure to achieve better building and ductwork airtightness.  

In this context, Eurovent Certita Certification decided to establish a new certification programme for Ventilation Ductwork Systems, opening a new chapter in the history of the Eurovent Certified Performance (ECP) certification mark, which concerned only products, not systems, until then.  

This paper summarizes the most recent results of the French database of ductwork airtightness. This database was created in 2016. It is fed through measurements performed by qualified testers according to a national scheme regarding ductwork. Measurements are mainly performed in building applying for the Effinergie + label which requires class A for ductwork airtightness. Therefore, results discuss in this paper only apply to the buildings of the database and cannot be generalized to all new buildings in France.

A ductwork system that has limited air leakage, within defined limits, will ensure that the design characteristics of the VAC system are sustained. It will also ensure that energy and operational costs are maintained at optimal levels. 

Does the UK have any requirements regarding ventilation ductwork airtightness and how does the UK assess the installed performance of ducted mechanical ventilation systems? 

Duct leakage airflow in existing ductwork can reach values of over 20% of the design air handling unit (AHU) airflow, undermining efficiency and effectiveness of HVAC systems. We have measured, in an existing building where ductwork was installed 20 years before, with no special care on duct leakage and tight building construction schedules, operational duct leakage rates between 10% and 40% of the AHUs airflows.