English

In Sweden, the energy usage in existing residential buildings amounted to 147 TWh in 2012, equivalent to almost 40 % of the final overall national energy usage. Among all the end users in building service sectors, 60 % of the final energy in Sweden is used for space heating and domestic hot water (DHW) production in 2013.

Mandatory building airtightness testing came gradually into force in the UK, France, Ireland and Denmark. It is considered in many other European countries because of the increasing weight of the building leakage energy impact on the overall energy performance of low-energy buildings. Therefore, because of related legal and financial issues, the building airtightness testing protocol and reporting have become crucial issues to have confidence in the test results as well as the consistency between the measurement results and values used in the energy performance calculation method.

Traditional building technologies establishing highly-breathing multi-layered wall systems provide healthy indoor environment and energy efficiency in buildings due to the use of lightweight, porous, water vapour permeable and thermal resistive building materials. The breathing performance of traditional buildings and materials that contribute to the healthy indoor conditions and air quality are needed to be investigated in detail.

During field measurements on the airtightness of passive houses, ventilations system’s roof penetrations showed to be one of the major leakage paths, as they were not sealed using the appropriate, durable techniques. Therefore, a series of laboratory measurements was conducted on wood-frame walls to study different air sealing solutions. The use of special airtight gaskets is compared to less advanced sealing methods such as sprayed polyurethane foam and the use of pieces of tape.

Reduction of energy consumption and green house gas emissions of buildings is a great challenge in Europe. In this context French energy performance regulation, RT2012, requires an improvement of the buildings' airtightness. In airtight buildings, ventilation must be perfectly controlled to ensure good indoor air quality.  However, many failures are observed when ventilation systems are inspected (Jobert, 2012). They are mainly due to bad conception, poor implementation and lack of maintenance.

MONICAIR --MONItoring & Control of Air quality in Individual Rooms-- is a pre-competitive field research project of a broad consortium of Dutch ventilation unit manufacturers and research institutes, supported by the Dutch government. The aim is to investigate the indoor air quality (IAQ) performance and energy characteristics of 9 different mechanical ventilation solutions in dwellings that meet strict air-tightness standards and comply with current building regulations.

In the “Exemplary Buildings” program of the Brussels Capital Region, building owners and designers are challenged to realise building projects of both high architectural quality and superior environmental performance. After a project competition phase in which the Exemplary Buildings are selected, winning projects are supported by grants and expert guidance throughout further design development and construction. Building envelope airtightness is an important aspect during the follow-up, given its influence on the net energy demand.

To realize the concept of low-energy buildings, an increase in the thermal insulation performance of building parts, especially the openings that show poor insulation performance, is necessary. In addition, an adequate level of thermal comfort is also needed within residential buildings. We have developed window-applied dynamic insulation (DI), and verified thermal insulation performance in chamber and field tests.

Zero Energy Buildings require airtightness and mechanical ventilation systems to provide air changes and energy saving. These requirements contrast with the principles of natural ventilation. Through a case study located in Modena, Italy, a design strategy is proposed as a solution to integrate natural and mechanical ventilation systems at different times of the year to reduce the energy consumption in a newly designed high-density ZEB. The internal comfort evaluation for the warm season is then verified with a multizone dynamic simulation and a CFD analysis.

The article describes the results of an experimental campaign carried out at ITC-CNR in outdoor test cells to evaluate the energy performance and the related comfort level achieved through a coupled system made up of a dynamic window and a heat recovery unit.