NZEB

The materials that compose the built environment have a key role in the resulting energy demand since their thermal properties affect the heat transfer processes. The use of cool materials aims at increasing the albedo of the urban surfaces and decreasing the heat absorbed by them. Cool materials can decrease roof temperatures, reduce energy needs for cooling and improve indoor comfort for spaces that are not air conditioned.

This study sets out to investigate to what extent the air permeability of a building envelope of a dwelling remains constant over longer periods of time. This was evaluated by executing an air pressurisation test in 30 dwellings located in Belgium and comparing these results to the initial measurement results obtained shortly after the construction of the buildings. The time span between both measurements ranges from 293 days to 4045 days. On average, the air infiltration rate of the building envelope increased with 24%, i.e. an increase of 64 m³/h at a 50 Pa pressure difference.

Earlier field measurements in Low Energy Buildings have shown that excess temperatures can easily occur during summertime in well-insulated houses, also in northern part of Europe. If a ground source heat pump is used for heating and there is a bidirectional ventilation system, the borehole can be used for free cooling in summertime and the chilled air can be distributed by the ventilation system. In this study, a simulation of a single family nZEB located in the Swedish city Gothenburg was conducted.

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.

EU energy policy encourages member states and public authorities to start converting building stock into nearly Zero Energy Buildings (nZEB) and adopting exemplary actions. ZEMedS project focuses on the issues related to the refurbishment of schools to nearly Zero Energy Buildings (nZEB) in France, Greece, Italy and Spain. Presently, there is a gap in national regulation of Mediterranean countries to embody the 2012/27 EED as far as renovation rates of public buildings are concerned.

Lecture rooms with their high, quickly fluctuating internal gains, e.g. changing from no occupation to full occupation within some minutes, are quite challenging when good indoor air-quality and thermal comfort is required in an extremely low energy building context.
One essential aspect is the perfect control of air flow and temperature based on reliable, continuous measurement in all relevant parts of the ventilation system.

In 2014 the first multi storey residential building planned and constructed to meet the Passivhaus Institute (Darmstadt) criteria was put in operation in Ljubljana, the capital of Slovenia. This massive-structure building is part of the FP7 EE-Highrise project, aiming to demonstrate nearly zero energy building (nZEB) technologies, an integrated design concept, and advanced systems for sustainable construction.

Net-zero energy building (NZEB) is thought to be the building of choice, but in practice, is also synonym  to high investment cost. It is, therefore, very important to investigate if the amount of the additional capital investment could be recouped from the energy saving (or generation). The investigation is particularly meaningful for industrial halls for the great energy saving potential (with respect to the high energy demand) and the ready energy generation possibility (due to favourable building geometry).

The European Union (EU) aims to a 20% reduction of the Europe's annual primary energy consumption by 2020. Furthermore, EU commits to reduce GHG emissions to 80-95% below 1990 levels by 2050. One of the main issues of the EU energy strategy is the radical improvement of the energy performance of new as well as existing buildings.