PR2017

It has already been proved that air leakage causes a great impact in the energy performance of buildings in cold climates. In recent years, many studies have been carried out in northern Europe, US and Canada. Regulations in these countries establish maximum air leakage rates for the construction of new dwellings and the refurbishment of the existing ones. However, there is a lack of knowledge relating to the housing stock in Spain.

A literature review has revealed that there is a very limited number of numerical or experimental studies of the air flow for mechanically ventilated large occupied rooms. Existing literature suggests that a room with more than 5 meters floor-to-ceiling height can be considered as a large space. The aim of this paper is to present a set of detailed air temperature and velocity measurements in a large open plan office located in south England.

An airtight building envelope ensures not only the energy-efficiency of a building, but also a damage free construction. Important to achieve optimal airtightness are the planning, implementation and materials. Long-term airtightness requires efforts in all three aspects. Airtightness products are being tested under lab conditions but these results cannot be transferred one-on-one onto buildings.

Heatwaves are often responsible for many deaths due to high temperature indoors. Energy savings is a key element in building design and refurbishment works to reduce the impact of climate change. Natural ventilation is often promoted as an indoor space cooling solution thanks to its energy saving potential.
The paper deals with prediction of heat-related health risks situations in naturally ventilated dwellings.

Mandatory building airtightness testing has come gradually into force in European countries mostly because of the increasing weight of building leakage energy impact on the overall energy performance of low-energy buildings. Therefore, airtightness level of new buildings has significantly improved in the last decade.
However, until now, low expertise is available about the durability of building airtightness at mid- and long-term scales.

Demand controlled ventilation (DCV) refers to a ventilation system with air flow rates that are controlled based on a measurement of an indoor air quality (IAQ) and/or thermal comfort parameter. DCV operates at reduced air flow rates during a large amount of the operation time. Due to this decrease, less energy is needed for fan operation and heating/cooling the supply air. However, uncertainty still exists about the IAQ performance and ventilation efficiency in the room, especially at lower air flow rates.

One of the key objectives of the IEA Annex 68 research programme entitled “Indoor Air Quality Design and Control in Low Energy Residential Buildings” is to provide a generic guideline for the design and operation of ventilation in residential buildings. They need to have minimal energy consumption, and at the same time maintain a high level of Indoor Air Quality (IAQ). The paper reports on preliminary results of an interview survey conducted among different stakeholders involved in design, installation and operation of residential ventilation in countries involved in the Annex.

The industry is now focusing in system solutions and the goal is to be able to deliver complete reliable, energy efficient solutions that is understandable and easy to maintain by the normal service personal.  
In order to do this the basic products have to perform exactly as they are described in the technical documentation. The documentation have to help the designer and the installer to actually build the system in the correct way without compromises from other stakeholders. 

There are several methods for measuring air tightness that may result in different values and sometimes quite different uncertainties. The two main approaches trade off bias and precision errors and thus result indifferent outcomes for accuracy and repeatability.  To interpret results from the two approaches, various questions need to be addressed, such as the need to measure the flow exponent, the need to make both pressurization and depressurization measurements and the role of wind in determining the accuracy and precision of the results.

Air infiltration holds a central role in building energy consumption and is associated to several building physics phenomena. Air infiltration in buildings due to wind-induced pressure is a complex process, strongly influenced by the turbulent nature of wind. This extended summary highlights the findings of a series of studies with focus on unsteady wind and its impact on air exchangesin buildings. The focus is on wind gustiness and its relation to air infiltration under natural conditions.