The impact of wind gusts on air infiltration in buildings

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.

Assessment of the durability of the airtightness of building elements via laboratory tests

The airtightness just after the end of a building phase is assumed to be relevant criteria for high energy performance. Testing on site the initial performance of the airtightness via the blower door test has become nowadays a common practice but generally implemented before the occupation of the building. But a lot of questions are still remaining targeting the sustainability of the performances.

Natural Pressure Differential – Infiltration Through Wind Results of a Long-Term Measurement

Wind pressure and thermal forces are driving forces for pressure difference on the building envelope. In European and German standards infiltration is calculated using wind speed, temperature difference and wind pressure coefficients resulting from upstream and downstream flow on the building envelope. This long term measurements shall present measured pressure differences on the building envelope in comparison to those calculations

Statistics, analysis and conclusions from 250,000 blower door tests, including ventilation types

With lower air leakage in modern homes, ventilation of homes has become more important than ever before. It seems however that we are getting it very wrong. A lack of ventilation can cause building sickness, with degradation of the physical building and also poor air quality which has a big impact on the occupants themselves. Our statistics show that designers and contractors are still not getting it right, leaving us with a generation of poorly ventilated housing stock.

Optimization of the airtightness and the flow rate of air in nearly zero energy buildings

The control of heat losses, inwards/out, in nearly zero energy buildings is of high importance. The transmission losses through the building envelope are easily reduced using larger amounts of insulation. Calculation of the impact of this action on the total energy demand of the building, is quite standard. It’s however much more difficult to determine the efficiency of actions to increase the airtightness of the building and the influence of the ventilation system.

Airtight duct systems [a simple way of improving a building’s energy efficiency without increased investment]

Against the background of increased global demands for energy efficiency, property owners should raise the standards of ductwork systems for ventilation, heating and air conditioning. This would not only save energy, but also mean lower installation costs, shorter assembly times and better air quality thanks to less leakage. The importance of energy-efficient buildings will increase in the future, not only due to rising electricity prices, but also due to increased environmental awareness.

Calibrating measurement gauges – expense and findings

This presentation will explain what exactly calibration should mean. It will also look into the hierarchy of and the differences between the calibration labs of national standards, accredited labs (like DAkkS, a national government-appointed accreditation body in Germany, or Cofrac – Comité français d’accréditation – in France), and manufacturer’s calibration labs. Even the labs themselves must have their own measuring devices checked in order to guarantee what is known as traceability to national standards, and to determine the measurement uncertainty of their testing devices.

Uncertainty in airflow rate estimation of daytime ventilation associated with atmospheric stability

We conducted observations of wind velocity profiles above a high-density area in Tokyo, Japan, using a Doppler LIDAR system. Obtained data of the exponent index for the power law, which is commonly used to describe the wind velocity profile, displayed diurnal variation, decreasing in the daytime, which is expected in unstable atmospheric conditions. This paper provides information on the uncertainty in the calculated ventilation airflow rate due to the use of a constant value for the exponent index.

Numerical evaluation of the airtightness impact on airflow pattern in mechanically ventilated dwellings in France

The objective of this paper is to assess the impact of the envelope airtightness on airflow patterns for single detached dwellings depending on the ventilation system.

Infiltration and Ventilation in a Very Tight, High Performance Home

The Net Zero Energy Residential Test Facility (NZERTF) was constructed at the National Institute of Standards and Technology (NIST) to support the development and adoption of cost-effective net zero energy designs and technologies. Key design objectives included providing occupant health and comfort through adequate ventilation and reduced indoor contaminant sources.

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