English

The performance of night ventilation to cool buildings is highly sensitive to the convective surface heat flux. As a result, simulations in BES-models may largely over- or underestimate the real cooling potential of this technique. To assess this, a series of transient 2D CFD-simulations, including thermal mass in floor and ceiling, are made with variation on ACH, inlet temperature and inlet location. It is shown that the location of the inlet strongly influences the surface averaged convective surface heat transfer coefficients at the ceiling.

Within this paper an annual performance and daylight comfort analysis of building integrated photovoltaic (BIPV) is discussed, evaluated and compared to a common façade solution. The daylight comfort analysis includes annual illuminance, glare evaluations, and further daylight factor calculation. Secondly, dynamic thermal simulations are performed. The energy consumption of the luminaries is considered as part of the thermal internal gains.

To minimize the total power consumption of a central air conditioning system, optimal control variables are necessary. A simulation of a central air conditioning system and its components are modeled. Modeling of air conditioning equipment required optimization, and power consumption formulas are created from experimental data. Optimal control is applied to the actual central air conditioning systems. The effectiveness of optimization and accuracy of optimization calculations are verified. Prediction of air conditioning load is required for the optimization calculation.

The building sector is responsible for a major part of the energy consumption. A considerable reduction can be achieved by improving the operation of the buildings. A methodology to organize and standar-dize the ongoing commissioning of buildings was de-veloped. The method consists of 4 steps. An impor-tant criterion developing this method was cost-effec-tiveness. Therefore a top-down approach was chosen. A minimal dataset was defined which was measured at all demonstration buildings. In this paper different modeling approaches within the methodology are discussed.

A methodology is presented that entails three ways to determine the heat losses of a dwelling in the heating season, each using a different set of data. The first method gives an indication of the theoretical ‘energetic’ quality of a dwelling, the second and third provide an indication of the actual ‘energetic’ quality of the dwelling. The third method includes effects of user behaviour. The methodology was applied to the private dwellings of (former) colleagues.

Nowadays, important efforts are deployed to reduce our current residential building consumption. The most common retrofit option concerns the air tightness and the thermal insulation improvement. However, this latter retrofit option could decrease the air indoor quality because of a reduction of air infiltration flow rate. Installation of an air-to-air heat recovery system allows for an efficient combination between consumption reduction due to the air tightness improvement and acceptable air indoor quality.

A combined simulation of the building envelope and the plant equipment is more realistic than simulating both separately and has the advantage that the modeler can use one software environment instead of multiple software environments. Tools that solve the coupled heat and moisture transfer for building components already exist. In this paper a software is introduced that uses the detailed simulation models of different building components (e.g., walls and windows) to generate a whole building simulation model. Furthermore, the extension of this software with HVAC models is described.

At present, for energy conservation, conscious utilization of natural ventilation is encouraged. However, the relationship between heat discharge through natural ventilation and heat loads has not been clarified yet. Accordingly, in this study, the effect of heat discharge through natural ventilation on indoor environments and heat removal structure is examined using a simulation model that can estimate the occupant thermal control behaviour and the characteristics of air conditioners.

The sensitivity to time resolution of boundary conditions is studied for dynamic integrated simulation of thermal and electrical networks of a net zero energy residential neighborhood.

To evaluate the requirements for passive school buildings, simplified calculation methods based on EN ISO 13790 are used. For these simplified calculations a fixed indoor temperature is used regardless the building properties, the climatic data or the building use data.  Considering the large impact of this temperature on the heating demand, an accurate estimation is important to obtain representative results. This paper analyses the accuracy of the fixed indoor temperature.