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uncertainty

On the contribution of steady wind to uncertainties in building pressurisation tests

This paper analyses the contribution of a steady wind to the uncertainties in building pressurisation tests, using the approach developed in another paper (Carrié and Leprince, 2016). The uncertainty due to wind is compared to the uncertainties due to other sources of uncertainty (bias, precision and deviation of flow exponent).
The main results of this study are:

Airtightness of Buildings – Considerations regarding the Zero-Flow Pressure and the Weighted Line of Organic Correlation

This paper discusses two particular points of the buildings airtightness measurement method (ISO 9972) in relation with the calculation of the combined standard uncertainty: (1) the zero-flow pressure difference and (2) the weighted line of organic correlation.

Assessment of airflow measurement uncertainty at terminal devices

Existing protocols for the inspection of mechanical residential systems poorly address both the assessment of uncertainties and recommendations or specifications for measurement methods and devices to be used to guarantee low measurement uncertainties. This paper gives the major elements of a new protocol developed within the Promevent project to overcome this problem. We have analyzed results from 180 airflow measurements performed in laboratory conditions in accordance with this protocol.

Uncertainty and sensitivity analysis of natural ventilation in high-rise apartment buildings

Quantification of natural ventilation rates is an important issue in HVAC system design. Natural ventilation in buildings depends on many parameters whose uncertainty varies significantly, and hence the results from a standard deterministic simulation approach could be unreliable.

Estimates of Uncertainty in Multi-Zone Air Leakage Measurements

Although standards for single-zone air leakage tests are widely used, there are no existing standards for several multi-zone cases including: 1) testing air leakage between adjacent zones or 2) testing leakage to the outside from a single unit in a multi-zone building. While a range of test procedures have been used to determine inter-zone leakage using fan-pressurization, the accuracy of the methods can vary significantly. Using field measurements and simulations, we compared the uncertainty in the leakage between two adjacent zones for different measurement and calculation methods.

Durability and measurement uncertainty of airtightness in extremely airtight dwellings

In this paper we present a series of leakage tests on extremely airtight dwellings (ACH50 < 0.6 upon completion) in which the durability of the airtightness and the measurement uncertainty involved are assessed. In literature, repeatability and reproducibility issues have been discussed by several authors, along with influences of weather. It remains unclear, however, to what extent the available uncertainty intervals are relative or absolute.

Airtightness of buildings - Calculation of combined standard uncertainty

The paper presents a calculation method for the combined standard uncertainty associated with the buildings airtightness measurement done in accordance with the ISO standard 9972:2006 (or EN 13829).

The method consists in an application of the law of propagation of uncertainty (JCGM 100:2008) combined with a linear regression (y = a x + b). It goes from the measured values to the air leakage rate and the air change rate.

Numerical evaluation of airtightness measurement protocols

In France, starting January 1st, 2013, the energy performance regulation will impose an airtightness treatment for every new residential building. This translates into several tens if not hundreds of thousands of envelope airtightness measurements a year that will have to be performed. They will have to be performed by a certified operator and according to the NF EN 13829 standard. This ISO standard is being revised under the Vienna agreement to become an EN ISO standard.

Interlaboratory tests for the determination of repeatability and reproducibility of buildings airtightness measurements

The issue of the uncertainty of building airtightness measurements has built up a greater importance since this topic was introduced in many regulations regarding the energy performance of buildings. Different studies have contributed to the evaluation of the uncertainty but the question is still incompletely solved in practice.
To contribute to the determination of the repeatability and reproducibility of these measurements in practice, the Belgian Building Research Institute organized interlaboratory tests with 10 other laboratories.

Quantification of uncertainty in thermal building simulation - Part 1: Stochastic building model.

In order to quantify uncertainty in thermal building simulation stochastic modelling is applied on a building model. An application of stochastic differential equations is presented in Part I comprising a general heat balance for an arbitrary number of loads and zones in a building to determine the thermal behaviour under random conditions. Randomness in the input as well as the model coefficients is considered. Two different approaches are presented namely equations for first and second order time varying statistical moments and Monte Carlo Simulation.