IBPSA2005

A comprehensive modeling of radiative and convective heat transfer of a compact double-skin facade equipped with venetian blind is proposed here. Results from detailed CFD model were used in order to compute convective heat transfer coefficients and the radiation heat transfer, parts of energy balances of the proposed nodal model. The convective heat transfer coefficients found were weak and only little influenced by slat tilt angles and solar radiation.

Despite the low energy and lower maintenance benefits of ground-source heat pump systems, little work has been undertaken in detailed analysis and simulation of such systems. Long-term transient ground heat transfer significantly affects the performance of these systems. Annual and multi-year simulation consequently becomes an invaluable tool in the design of such systems – both in terms of calculating annual building loads and long-term ground thermal response. Models of vertical ground loop heat exchanges and water-to-water heat pumps have been implemented in the EnergyPlus program.

The paper describes a research project which addresses the problem of supervisory control of systems which include a range of heat sources combined with active and passive thermal storage. The work is based around a prototype building which has a ventilated PV array, solar air and water heating, biomass-fired boiler and a stratified thermal store. The supervisory control problem is, for each source, whether to deploy the energy directly into the building, store for later use or to reject to the environment.

We analyzed the thermal environment within Kyoto city using a numerical model that considers three elements: the unsteady-state heat conduction of building walls and ground surfaces, radiation heat exchange between walls and ground surfaces, and airflow approximated by computational fluid dynamics (CFD). We found that the model accurately simulates the thermal environment accurately within wide urban canyons. However, the various canyon shapes within a city each have unique of thermal characteristics.

The use of Matlab, a tool for mathematical programming, is actually increasing in a large number of fields. Together with its dynamic simulation toolbox Simulink, originally developed for control and automation applications, it has become a powerful tool that is suitable for a large number of applications. In the field of building and HVAC, the number of users of Matlab/Simulink has also been increasing rapidly in the last years.

In this paper, microscopic and macroscopic flow analyses have been employed to identify and analyze the causes of discrepancies of power law zonal models. The analyses show that the use of constant flow coefficient (Kf ) is one of the reasons for the discrepancy. Computational Fluid Dynamics (CFD) was employed to estimate Kf for isothermal condition. The variations of Kf as function of room height were investigated for two types and locations of diffusers. Five levels of Reynolds numbers (Re) were used.

It is beneficial for the safe and optimal operation of system and energy conservation to find out and eliminate the faults existing in HVAC systems in time. For a large-scale and complex HVAC system, an automatic fault detection and diagnosis system is needed to ensure it to operate safely and reliably. Principal component analysis (PCA) approach has been used to detect and recover sensor faults in central chilling system through simulation data. However, it is found that sensor validation index (SVI) of PCA cannot identify the flow meter fault in the system.

Communications between buildings and their occupants through multimodal Human Computer Interactions (HCI) can dramatically enhance the way buildings are experienced. Although building performance data is becoming more readily available, no research has been established to enable visualization of and interaction with this information in a robust way. This paper will present a method that will allow users to visualize and interact with building performance data in real space.

This paper reports on progress of an ongoing research project, which aims to achieve better control modeling in building performance simulation by integrating distributed computer programs. Recent developments show that there is a need to enhance building performance assessments by integrating new simulation features in order to predict the overall effect of innovative control strategies for integrated building systems. However, both domain independent control modeling environments and domain specific building performance simulation, have their own restrictions.

Stand-alone software for predicting contaminant transport and behaviour is well developed, but to be more effective, it needs to be integrated within whole building simulation. This paper describes implementation of such a model within whole building dynamic simulation. The model is further enhanced by allowing specification of filter efficiencies, source/sink models, first order chemical reactions, contaminant based control and scheduled ambient concentration profiling. The model was validated against analytical solutions and for complex cases against CONTAM and COMIS.