M. Kosir1* , Z. Kristl1, A. Krainer1

1 IUniversity of Ljubljana, Faculty of Civil and Geodetic Engineering, Chair for Buildings and Constructional

Comlexes, Jamova cesta 2, 1000 Ljubljana, Slovenia
Corresponding Author, mkosir@kske. fgg. uni-lj. si

Abstract

Automated regulation of building envelope can substantially advance the functioning of its components, consequently improving internal living and working conditions in buildings. The present paper deals with a dynamically automated control of shading in buildings during mid­seasons. The developed automated system is based on fuzzy logic controllers and is installed in purposely build test cell with an opening on the southern side. The system is conceived as a thermal and illuminance controller of internal living and working environment, but for the purpose of experiments presented in this paper only the thermal control loop was used. The focus of presented experiments was the investigation of the influence of shading device automation on the reduction or elimination of cooling loads in buildings during spring and autumn. Proper functioning and fine-tuning of the fuzzy controller was achieved through a series of tests conducted in spring time. Experimental results showed that with adequate level of automation movable shading devices can substantially reduce cooling loads during mid-seasons.

As a consequence internal environmental conditions can be made more comfortable for the users and the energy consumption of buildings can be reduced.

Keywords: automated control, automated shading, fuzzy controller, cooling load reduction

1. Introduction

Internal living conditions in temperate climate during mid-seasons can be in most cases attained by properly regulated building envelope. With adequate shading of transparent parts overheating of internal spaces can be reduced or completely eliminated. During mid-seasons (spring and autumn) the amount of available solar radiation can be high and at the same time the external ambient temperatures can be relatively low. In such conditions the impact of properly regulated shading on the internal temperature can be substantial. Additional positive effects can be attained by implementing natural ventilation and radiative cooling during night time. The automated regulation system presented in this paper was designed according to the above described presumptions about thermal conditions during spring and autumn.

In temperate climate weather during spring and autumn is exceptionally varied and prone to rapid changes. Because of these climatic characteristics the control of movable shading elements has to be automated if adequate response of the system is desired. Automated control of shading devices incorporated in the building envelope has to assure optimum balance between aspects of energy consumption and internal living and working conditions [1, 2]. Best results can be obtained by

applying advanced control systems based on the developments in the field of “artificial intelligence” technologies. One of the possibilities is a system based on fuzzy logic, which (if properly tuned) can be

The presented fuzzy system was realised as a thermal and illuminace fuzzy controller for the internal living and working environment. The basic controller architecture was built around two fuzzy control loops, the first for thermal conditions and the second for illuminance. The controller operated in real­time conditions as well as in real environment. The whole system was designed for an experimental test cell with south oriented window. The dimensions of the cell were 1 m x 1 m x 1 m and the south oriented window was 1 m x 1 m double glazed float glass with air fill and wooden frame. The whole cell was constructed from 20 cm thick aerated concrete blocks with ventilated roof and ground to prevent influences of the immediate surfaces on the interior. The small volume of the cell, large surface of glazing, low accumulation mass and poor thermal insulation meant that the thermal behaviour of the cell would be exaggerated in comparison to real buildings. This was done intentionally as to enable quick execution of experiments where thermal processes in the cell become obvious in relatively short time. The experiments presented in this paper were designed with the intention to test the possibilities of automated shading and reduction of cooling loads in buildings during mid-seasons.