simulation

Within the European project - Friendly Heating - a local heating system is designed. The main goal is not to heat the monumental churches themselves, in order to prevent damage to valuable art works and the building itself. The idea is to provide a thermal comfort zone for the people in the pew using radiant heat sources. Measurements in a climate room are used to a) evaluate the local climate created by the bench heating system and b) evaluate the CFD model. The results will be used in ongoing research on the prediction of the indoor climate in a church under real climate conditions.

The techniques available for the simulation of the complex geometries common in air diffusers are quite different from the ones optimized for a complete room simulation. For this reason the full room simulation usually neglects the complexities of the diffusers introducing ad hoc boundary conditions
often requiring extensive experimental setups for a correct definition. An alternative approach could be the use of numerical analysis for the diffuser characterization. In this work a detailed analysis

This paper describes a comparison between internal and external run-time coupling of CFD and building energy simulation software. Internal coupling can be seen as the traditional way of developing software, i.e. the capabilities of existing software are expanded by merging codes. With external coupling, two or more software packages run simultaneously while exchanging calculation results at appropriate time intervals.

The conversion of CAD models into 3D Cartesian-defined geometries is presented, and a two-pass algorithm to perform the transformation is described. The methodology for implementing the numerical solution of fire dynamics problems involving the FDS simulation program is tested. The results from these predictions are visualized on the original geometry using elements which take into account the optical properties of the phenomena for a realistic rendering of smoke and fire.

The airflow conditions in an experimental pig housing unit are examined both experimentally and numerically (simulation) with particular focus on the airflow conditions in the occupational zone of the animals. Two heating setups are used, and the temperature is measured in a horizontal profile at the floor and at the ceiling. Good concordances between the measurements and the simulations are reached at the floor level. At the ceiling level, the conformity to the measuring results is unsatisfactory.

Hybrid ventilation is one promising approach to reduce energy consumption in office buildings. On the one hand, a minimum air change rate is supplied to the rooms, even if the windows are closed. On the other hand, the energy demand for ventilation can be reduced if natural forces (wind and buoyancy driven air flow) are used to ventilate the building. The user behaviour has an important but often unknown influence on the thermal building performance and the indoor climate. Thus, an accurate user model should be used in designing hybrid ventilation.

For retrofitting of existing dwellings MVHR is seldom applied, despite the potential in energy saving and improving thermal comfort and indoor air quality. Major barriers and limitations for application are lack of space, especially for the supply ducts and the MVHR units as well as the complexity of execution. Also initial costs are an important barrier. Limiting supply ducts could be beneficial for application in single family dwellings. In a study some configurations with simplified air supply with MVHR in single family dwellings have been investigated.

The article describes the influence of the supply air devices that are part of hybrid ventilation system which is being developed within a EU funded project RESHYVENT as a part of this project, on thermal comfort in living-room of a three-bedroom apartment. The supply air radiator and the supply air convector are compared. The fresh air is sucked through a supply air convector and supply air radiator respectively and the air leakage through the facade is assumed too. 2 variants, which cover different outdoor temperature and supply air temperature for each device, have been solved.

This paper summarizes the work within the EU RESHYVENT project in regard to design parameters for the performance assessment of hybrid ventilation systems. A framework for performance assessment based on simulation was developed. Performance criteria were defined for air flows, indoor air quality, thermal comfort, acoustics, energy, and emissions.

The Dutch housing stock consists for about 70% of single family houses with an average N50 of about 7-9 ACH and for 30% of apartments with an average N50 of about 3-4 ACH.New single family houses are much more airtight. In the period 1970 to 2000 the air tightness increased to an N50 of about 3 - 4 ACH. Apartments have nowadays about the same or a slightly better air tightness then before 1970.Another trend is the downward tendency of occupant numbers per dwelling.