The presence of a blind adjacent to a window affects the natural convective air flow over the window and natural convective heat transfer from the window to the room. Most numerical studies of convective heat transfer between a window-blind system and a room are based on the assumption that the flow remains laminar. However, in the case of larger windows it is to be expected that transition to turbulent flow will occur in the flow over the window. The aim of the present study was to numerically determine the effect of Venetian blind on laminar-to-turbulent transition in the flow over a simple recessed window and on the convective heat transfer from the window. An approximate model of a recessed window that is covered by a venetian blind has been considered. The fluid properties have been assumed constant except for the density change with temperature that gives rise to the buoyancy forces, this being dealt with using the Boussinesq approach. Radiant and conductive heat transfer effects have been neglected. However in the present study the case where there is a constant heat generation rate in the blind slats, as the result of solar radiation absorbed by the slats of the blind, has been considered. The k-epsilon turbulence model with the full effects of the buoyancy forces being accounted for has been used in obtaining the solution. The turbulent, steady and two dimensional governing equations have been solved using the commercial finite-volume based CFD code FLUENT. Results are generated for different blind slat angles, for different distances of the pivot point of the slats from the window and for different constant heat generation rates in the slats. The results show that over a wide range of Rayleigh number, the distance of the blind to the window has a stronger effect on the convective heat transfer from the window and also on the laminar to turbulent transition in the flow over the window than the blind slat angle. Heat generation in the slats increases the Mean Nusselt number and this effect increases as the Rayleigh number decreases. / Thesis (Master, Mechanical and Materials Engineering) -- Queen's University, 2011-09-22 21:17:31.777

The demand for automated home solutions is growing and it has created a market for automated blinds. For now most of these solutions seem to focus on fully opening and closing, either rolling blinds or slat blinds, with different electronic solutions. There doesn’t seem to be many solutions for continuously regulating light inlet based on ambient light. This project examined the possibilities of continuously regulating the amount of natural light let through a window. This was tested by measuring ambient light on one side of the blind with light dependant resistors (LDR’s) and regulating a Venetian blind based on measured light intensity. A feed-forward controller was implemented, programmed on an Arduino Uno board, to control sensors and actuators that regulate the blind. A prototype unit was built on a window-resembling wooden frame to evaluate the performance of the controller. The light sensitivity of LDR’s were sufficient for measuring differences in ambient light in different conditions where an automated blind could be used. The final prototype could be set to adjust light inlet in increments for changes in ambient light, thereby opening up to uses beyond simply closing and opening a light inlet. Future improvements could be to implement a feedback controller (e.g. a PID controller). The controller could be set to a certain reference as preferred ambient lighting in a room, thereby letting the controller adjust the blinds towards that reference value while conditions outside and inside change during the day. This could also be implemented in already existing smart home solutions. / Efterfrågan på automatiserade hemmalöningar är växande och det har skapat en marknad för automatiserade persienner. För nuvarande verkar det de flesta lösningarna fokusera på att helt öppna eller stänga, antingen rullgardiner eller persienner, med olika elektriska lösningar. Det verkar inte finnas många lösningar med kontinuerlig justering av inkommande omgivningsljus. Detta projekt utforskar möjligheterna för kontinuerlig justering av mängden naturligt ljus som släpps igenom ett fönster. Detta gjordes genom att mäta omgivande ljus på ena sidan av persiennen med fotoresistorer och reglera persiennen baserat på den uppmätta ljusintensiteten. Framkopplad styrning implementerades, programmerad på en Arduino Uno, för att styra sensorer och ställdon som reglerar persiennen. En prototypenhet byggdes på en fönsterliknande träram för att utvärdera prestandan av styrenheten.  Ljuskänsligheten i fotoresistorerna var tillräcklig för att mäta skillnader i omgivningsljus för de olika förhållanden där automatiserade persienner skulle kunna användas. Den slutgiltiga prototypen kunde ställas in att justera ljusinsläppet stegvis för skillnader i omgivningsljus, vari nya användningsområden öppnas upp utöver att endast stänga och öppna ett ljusinsläpp.  Framtida förbättringar skulle kunna vara att implementera en återkopplande styrning (t.ex. PID-styrning). Styrenheten skulle kunna ställas in till ett specifikt referensvärde på önskat omgivande ljus i ett rum, vari kontrollern justerar persiennerna för att hålla det önskade referensvärdet medan förhållanden utomhus och inomhus varierar under dagen. Detta skulle även kunna implementeras i redan befintliga smarta lösningar för hemmet.

This final work is focused on the space and light and its screening by the medium of the venetian blinds which are used to separate inner and outer space. This instalation made with 5 Venetian blinds is a parallel to the book. The object is in a form of the hexagon space. It mirrors surrounding story and closes it in the pages by the mirror film. The text is called Chronicle of the melancholy and indicates the intimite of the space of book. Between lines there is a penetration of the space and light behind the pages.