Pavel Valicek

Measurement of illuminance of interior lighting system automatically dimmed to the constant level depending on daylight

The article describes verifying of behaviour of dimming in a regulated lighting system in Smart Home (SH) which was controlled to the constant level of illuminance. The proposed method of measuring was realized as an upgrade for evaluation of curves of interior illuminance caused by daylight. A reference room in SH with a measuring device evaluating illuminance in the places of visual tasks and at the same time scanning illuminance caused by daylight on an outdoor unshadowed horizontal plane was used for measuring. The used measuring device was supplied with a dimmable lighting system of artificial lighting using luminance controller situated on the ceiling of the room in combination with controlling system KNX to reach the constant level of illuminance regarding the influence of both elements of artificial light and daylight. The article shows that there might be difference between the set value of illuminance, which is regulated by a KNX system, and real illuminance in the place of a visual task. Due to this difference, the lighting system may not meet the normative requirements, which is absolutely inacceptable.

Suggestion of long-term measuring of daylight contributions in interiors

The confirmation of the prediction system model of economies in illumination systems with regulation for constant illuminance required the realization of a measuring device for long-term measuring of illuminance in interior workplaces. The suggested system makes this measuring possible in 10 points of interior and at the same time outdoor on the plain without shadows.

Lighting system behaviour verification of interior illumination regulated to constant level of illuminance

This article represents a continuation of a longstanding research concerning behaviour prediction (consumption) of lighting systems collected on the constant level of illuminance depending on daylight. Due to the occurrences of differences between the prediction model and the actual long-standing lighting measurement in monitored lighting system it has been vitally important to seek the source of such differences. It has been discovered that actual savings amount is higher than predicted savings amount. Such result has been reached due to the fact, that regulated lighting systems are being collected during daylight and artificial lighting cooperation in higher rates than desired. It has been resulting in collecting to a lighting level which has not complied with normative demands for requested visual tasks. This situation is unacceptable on the basis of the hygienic conditions. This is caused in the view of the fact that in some situations the immediate lighting level has not even reached the hygienic minimum demands for permanent residence.

Interior lightning system sensors placement optimization

The article deals with optimization of light distribution and illuminance sensor placement for interior space on the base of dimmable lighting systems power consumption. In some cases the real lighting system works not properly when there is control by illuminance sensors placed on the ceiling. There was a model of interior room created and modeling results compared with special laboratory for light measurements at Technical University of Ostrava. A set of the measurement and calculation was realized for optimal illuminance sensor placement. Results are discussed in the conclusion.

Infrared thermographic measurement of the surface temperature and emissivity of glossy materials

Determination of the surface temperature and emissivity of glossy materials is a complicated task due to the relatively wide range of emissivity values and the reflection of infrared radiation from surrounding objects. As a consequence, standard methods used in infrared thermography are not applicable. In this article, an alternative method is proposed for the measurement of the surface temperature and emissivity of glossy materials used in the external structures of buildings that is based on an external source of thermal radiation. It is shown that the method gives quite accurate values of emissivity of both low- and high-emissivity glossy materials, whereas the surface temperature of low-emissivity glossy materials is less accurate and strongly depends on the accuracy of the used thermal camera.

Illuminance evaluation in automatically dimmed interior lighting systems

To verify a quality of dimmed lighting systems with illuminance regulation to constant level it was necessary to develop an automatic measuring system. This system works as a long-term measurement of illuminance of interior workplace (10 illuminance at the same time) together with the daylight measurement. This system measures horizontal illuminance at the workplace as it is required by norms. However, the sensors used in dimmed interior lighting systems are generally placed on the ceiling and that is why the automatic system could not work well and final measured illuminance at the workplace could be different from the set request (norm) if there is a dynamic daylight in the room.