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This study introduces a new control framework, based on a low-cost programmable luminance acquisition (HDR) sensor placed on the interior surface of the window. The new sensor, photometrically and geometrically calibrated, can capture luminance and geometry details of potential glare sources within its entire visual span in real time, while also providing feedback about transmitted illuminance. Real-time processing of the sensor data enables an alternate, low-cost glare sensing system that can be directly used in daylighting controls and building automation systems. This novel framework is the first proposed solution to address direct and reflective glare in a straightforward and efficient way and therefore it is a significant step towards improving the visual environment in perimeter building zones.

Shading fabrics have the ability to reduce daylight glare and provide privacy when needed. Recent studies have shown that glare indices such as DGP and its simplified version can be used to predict daylight glare through shades when the sun is not within the field of view. However, there are no comprehensive studies on glare sensation with the sun visible through the fabric – a situation that happens in office buildings – and therefore the applicability of glare indices for such conditions is uncertain. Shades with very low openness factors transmit only a small amount of direct sunlight due to their weave density; nevertheless, existing glare metrics may show intolerable conditions for these cases, while specific studies with human subjects are nearly non-existent. This paper presents an experimental study on daylight glare evaluation for the case of shading fabrics with the sun within the field of view. 41 human subjects (n=41) were tested while performing specific office activities, with 14 shade products of different openness factors and visible transmittance values (direct and total light transmission characteristics). The measured variables and survey results were used to: (i) associate discomfort glare with measured and modeled parameters for these cases (ii) evaluate the robustness of existing glare indices for these cases (iii) examine recently suggested alternate (direct and total vertical illuminance) criteria for glare assessment through fabrics, extract discomfort thresholds and suggest a new related index and (iv) propose corrections in the DGP equation when the sun is visible through the shades, which could be generalized for other systems following a similar approach. Combining illuminance-based metrics and existing glare indices can result in a more realistic glare evaluation covering all cases with and without the sun through shading fabrics. The new results can be inversely used as thresholds for selecting optical properties of shades to ensure glare protection, as well as for the development of glare-based shading controls.Â

This presentation will be a demo of a new intractive tool and a web-based interactive graphical user interface for estimating the potential cooling energy savings with exterior solar protection devices and interior light-shelves. The modeling tool takes into account relevant parameters and allows the user to input basic information about the size of the building, size of exterior facades and windows, and glazing and framing optical and thermal properties. The user can then select among a variety of exterior solar protection devices (e.g., horizontal louvers, vertical blades, etc) of different shapes, tilt angles and dimensions, and place them on different locations on the façade. Other options include interior light-shelves and louvers with integrated PV panels. The tool reads climatic information from a TMY3 database and performs a thermal analysis of the space using a simplified heat balance method, as well as a lighting analysis when light-shelves are selected. The analysis runs real-time in a few seconds and provides the potential cooling energy savings and lighting benefits with the selected shading systems. The users can easily compare between different shading solutions and geometries on a relative basis. The reliability of data exchange and the practical, user-friendly web interface are major advantages of the new interactive tool.

Daylight glare evaluation has been the recent focus of research on visual comfort since newer office buildings have large glass facades offering daylight provision and outdoor views. Available glare indices are related to source luminance size and location, view direction and background luminance. The Daylight Glare Probability index that considers vertical illuminance at the eye level, has been identified as one of the reliable metrics, since it was based on experiments with real human subjects. In this study, extensive experiments were conducted in a full-scale private office environment with dynamic shading controls, to measure interior luminance and illuminance conditions under variable sky conditions and shading control strategies. A high dynamic range camera with a fish eye lens was used to capture the luminance in the field of view, while horizontal and vertical illuminance was measured at different positions. The images were processed for calculating DGP values based on the “evalglare” method. The results are used to evaluate the efficiency of control strategies in terms of glare probability, while correlations between indoor illuminances, sky conditions and DGP may lead to simplified criteria and guidelines for controlling daylight glare in office spaces. Finally, the experimental results can be used for a daylight model validation for spaces with dynamic facades.

134 σ., Εθνικό Μετσόβιο Πολυτεχνείο--Μεταπτυχιακή Εργασία. Διεπιστημονικό-Διατμηματικό Πρόγραμμα Μεταπτυχιακών Σπουδών (Δ.Π.Μ.Σ.) "Σχεδιασμός & Κατασκευή Υπογείων Έργων", Έγινε σύγκριση της ευστάθειας μετώπου, τόσο για ανυσποστήρικτο, όσο και για ενισχυμένο με αγκύρια Fibreglass μέτωπο, και μέσω της διαμόρφωσης κατάλληλου συντελεστή, κατέστη δυνατή η επιλογή του οικονομικότερου καννάβου, ανάλογα με τα δεδομένα χαρακτηριστικά του εδάφους. Παράλληλα με τα παραπάνω, διαμορφώθηκε μια σχετικά πλήρης βάση δεδομένων για την έκθλιψη σε ανυποστήρικτα και ενισχυμένα μέτωπα, με διαφόρους καννάβους αγκυρίων, χρησιμοποιώντας μονοδιάστατες, διδιάστατες, και τριδιάστατες εκφράσεις αυτής., The main goal had been to compare the face extrusion between the unsupported state of the tunnel face, and the one when the face was supported using fibreglass anchors, in different densities. Using the results of that comparison, we have been able to export some charts that expressed the minimum density of the required support measures, so the future designer would have the chance to start his analyses using the most inexpensive density. To do the above, we had to built a big database of the extrusion results, for various depths, friction angles, cohesions, Young's Modules, and anhors densities, and to express the extrusion as three different values, using 1D, 2D and 3D forms of it. This database will be available for future research use., Ιάσων Γ. Κωνστάντζος