English

Computational Fluid Dynamics (CFD) has evolved from an academic tool to an important commercial design tool over the past decades. In the present paper the accuracy of two equation turbulence models for 3-D internal air flows is investigated in terms of mean quantities and topological aspects. Results for pseudo 2-D and full 3-D simulations using the k-ε model and the Baseline (BSL) k-ω model of Menter, respectively, are compared with LDA measurements (Nielsen, 1990) and PIV measurements (Pedersen & Meyer, 2002).

Horizontal diffuse illuminance and direct illuminance were estimated by measured sky luminance distribution to investigate the consistency among global, diffuse and direct illuminance for a long-term IDMP data in Kyoto, Japan. In order to estimate the diffuse and direct illuminance by sky luminance distribution, it is necessary to identify the direct circumsolar region of the sky. This study introduced a new method to identify the direct region by comparing the measured diffuse illuminance and the calculated illuminance came from outside the supposed region.

The present paper investigates, both experimentally and by simulation, the influence of faulty VAV units that do not affect the zone temperature on total energy consumption of a VAV system. In an experimental room, the respective total energy consumptions of both normal operation and faulty operation were measured. The results indicate that a faulty unit affects other normal units, causing an energy waste of approximately 20-50%.

The building simulation tool Domus has been recently renamed as PowerDomus for whole-building hygrothermal and energy simulation. Enhancements have been accomplished by improving the features for input and output data applied to multizone buildings, by adding HVAC systems and plants, by adding attics among other Graphical User Interface (GUI) features and by improving the numerical algorithms for calculating Sun angles, shading projections and moisture prediction through composite walls using moisture content as driving potential.

Numerous problems can occur for an investigator of larger datasets, e.g. how to handle dimensionality, many variables and few observations, few variables and many observations, correlations, missing data, noise and to extract information from all data simultaneously. Multivariate analysis (MVA) is an established method for dealing with such problems. In this work, we introduce a methodology based on MVA, which was developed to model the building energy performance from the perspective of the property holder.

Highly glazed buildings are often considered to be airy, light and transparent with more access to daylight than traditional buildings, but their energy efficiency is often questioned. This article deals with energy and indoor climate simulations of single skin office buildings in Sweden using a dynamic energy simulation tool. Different building alternatives were studied with 30%, 60% and 100% window area.

The paper deals with two construction details and discusses the opportunities and limits of their computer aided building simulation. Both details occur in the area of building renovation and modernization. The first is a 3-D joint of a partially protruding roof terrace with surrounding walls and a pitched roof, and the second is a fragment of the thick, rough, non-plastered stone wall of a building monument with adjacent additionally insulated walls and roof.

To have a proper energy management in buildings, it is necessary to evaluate its HVAC system. To properly compare operating strategies and solve possible problems, one needs to reproduce the building and its HVAC system behavior under real life conditions (building materials, cooling, heating and ventilation demands, meteorological conditions, etc.).

This paper deals with the issue of using micro- Combined Heating and Power plants (mCHP) in high-performance houses in terms of energy conservation and cost savings. On the one hand, since mCHP systems have only a modest electrical conversion efficiency, effective exploitation of the thermal output is critical to achieving high levels of energy efficiency. On the other hand, modern high performance residential buildings display a heat-topower load ratio that does not match well with the heat-to-power supply ratio of mCHP.