This article describes five blower door measurements – each made with a different objective – carried out on large buildings. Proof of air tightness is required to guarantee the operational capability of ventilation systems or to enable fire protection by

This study investigates numerically the occurrence and duration of higher relative humidities in a cold attic space, which are a consequence of excessive moisture supply from ventilating the attic and from air infiltration from inside the dwelling. Hygrothermal states of the attic air zone and the adjacent construction elements are calculated by a whole building heat, air and moisture simulation tool. Airflows to the attic are determined by taking into account the total distribution of pressure around and inside a building.

Building materials and furnishing used in contact with indoor air have some effect to moderate the variations of indoor humidity in occupied buildings. Very low humidity can be alleviated in winter, as well as can high indoor humidity in summer and during high occupancy loads. Thus, materials can possibly be used as a passive means of establishing indoor climatic conditions, which are comfortable for human occupancy. But so far there has been a lack of a standardized figure to characterize the moisture buffering ability of materials.

The paper gives an outline of existing modelling capabilities as well as an overview of current developments in integral modelling of hygrothermal conditions for whole buildings as presented within IEA Annex 41. Such models deal with the heat, air and moisture conditions of most relevant elements of buildings: The indoor air, the building envelope, inside constructions and furnishing. These building elements interact with each other and they are influenced by the use of the building, the building services, and the outside climate.

Combined heat, air and moisture (HAM) simulation at the envelope level and building simulation havebeen two separate activities for many decades now. In HAM-models, inside temperature and inside relative humidity are handled as known boundary condition, while all building simulation tools predict inside temperatures and net energy demand without any consideration for relative humidity.Things started to change when airflow modeling became doable.

At the conceptual design stage, one needs to pay considerable attention to both the energy as well as indoor air quality (IAQ) requirements. Often, designers tend to overlook ventilation and IAQ issues and conceptualise the HVAC design more from energy considerations. An energy efficient design of airconditioning system in hot and humid climates is quite challenging in view of the high humidity levels prevailing all-year round. This paper outlines some of the key factors that could lead to inadequate or inefficient ventilation and, thereby, poor IAQ.

This paper presents an analysis of energy and comfort performance of typical office buildings for summer cooling in five climate zones in China using the natural ventilation assessment tool, which is developed based on the integrated thermal and airflow model. Harbin, Beijing, Shanghai, Kunming and Guangzhou are selected as the five representative cities for Very Cold, Cold, Hot Summer and Cold Winter, Mild and Hot Summer and Warm Winter zones respectively. The cooling energy consumption with air conditioning system is compared to that with natural ventilation system.

An earth-air heat exchanger (EAHX) has been implemented in a low-energy office building in Kortrijk,Belgium. An extensive monitoring campaign was conducted to define the energy consumption in the building and the contribution of the EAHX to energy savings. This paper presents the results of the measurements and compares the measured performance of the EAHX to the building energy use and to results of a simulation model for 3D transient heat transfer.

A multi-disciplinary study to comprehensively measure and analyze operational performance and indoor environmental conditions in a sample of typical, commercial office buildings in the United States is described. The study will provide data that are currently not available. The indoor building factors that will be investigated during this study have never been formally studied in a comprehensive and systematic manner.

Natural night ventilation is an energy efficient way to improve thermal summer comfort. Coupled thermal and ventilation simulation tools predict the performances. Nevertheless, the reliability of the simulation results with regard to the assumptions in the input, is still unclear. Uncertainty analysis is chosen to determine the uncertainty on the predicted performances of natural night ventilation. In addition, sensitivity analysis defines the most important input parameters causing this uncertainty.