IBPSA1997

The research we develop consists in evaluating "radiative comfort" during no heating periods in dwelling space and particularly in office buildings. The expression "radiative comfort" is used to characterize the thermal and visual component of the feeling of people set in indoor environments submitted to sky and sun irradiation by bay windows. Two numerical models, one for the visual aspect (Genelux) and the other for the thermal aspect (TRNSYS), have been connected together to carry out simulations on radiative comfort in office buildings.

The control strategy of the thermal storage HVAC system gives a large effect to the storage efficiency which dominates the tank volume to a great extent. Authors introduce how the temperature distribution of the tank varies and gives a considerable damage on the HVAC system performance, and how this kind of fault can be detected and diagnosed through the pattern recognition of temperature profiles which are obtained by storage system simulations.

A simplified heat transfer calculation method for underground buildings is developed. The method is based on the results from the ITPE method and is suitable for seasonal heat loss calculation. The simplified method consists of a set of equations for estimating the monthly total heat flow between an underground building and ground as a function of a wide range of variables such as building dimensions, insulation configurations, and soil thermal properties. The equations are designed to accept continuously variable input values.

The need for a decrease in the energy consumption of buildings implies an adequate understanding of control strategies. This requires an intensive use of simulation tools for the design and test of controllers of HVAC equipment. It is noticed that simulation software commonly used in control engineering do not provide any model of HVAC equipment. The SIMBAD project has been set up to develop a toolbox of such models adapted to the needs in the control field.

The  traditional  round  hut  has  been  analysed  by simulating the sensitivity of its different components in order to establish their relative performance. This has been done using SERIRES, a thermal simulation package suitable for warm climates. The hut is simulated in  the climate of Zambia which has a tropical upland climate. The results show that the mud and pole wall is the most influential element of the house. The opening sizes have been found to be quite dominant too, hence the small openings of the hut are quite suitable.

Within the framework of the validation methodology of our computer software CLIM2000, we asked 12 users to do the same validation exercise (prediction of energy consumption of a residential house) in order to evaluate the influence of the model user on the imulated results. The first part of this article describes the conditions in which this exercise was carried out.

We show here the actual state of a project based on n object-oriented philosophy, MotorLab. It is an interface to general and widely available interactive modeling environments (Matlab[2] and Ylab[3]1), and relies on the use of the description structure during the whole modeling process. Furthermore, we tried from the beginning to base the modeling process in MotorLab on a technological description without need, when possible, to ask the user for lower-level indications. The presented prototype is running, but many works remains to be done to reach the fixed objectives.

By describing three recent case-studies, this paper aims to elaborate the current state of building energy modelling and simulation in the Czech Republic in general, and at the Czech Technical University (CTU) in Prague in particular. The studies which are described were carried out at the Department of Environmental Engineering, Faculty of Mechanical Engineering, concern practical problems related to heating, ventilating, and airconditioning (HVAC) systems.

Thermal storage tanks are widely used in Japan mainly to shift electrical energy usage to night time for the purpose of peak demand reduction. However, the operation of the system has not often been accepted with satisfaction in a real field. Authors developed a method ensuring rational operation by utilizing predicted air-conditioning load based on an ARX model derived from building load simulation. The rational operation is achieved considering the predicted load and performance of HVAC components.

Hollow core ventilated slab systems provide an effective means of utilizing the building structure as a thermal store. The optimum control strategy for the system would be one that minimizes energy costs without prejudicing the occupant thermal comfort. This paper describes an implementation of one such strategy in which the optimum operation of the plant is predicted for the next day. The controller incorporates algorithms for predicting the ambient temperature and solar radiation over the next 24 hours.