Monitoring and modelling of manually-controlled Venetian blinds in private offices: a pilot study

Abstract

This study presents results from a window blind usage survey and field study that was conducted in California, USA during a period spanning from the vernal equinox to the winter solstice. A total of 113 office building occupants participated in the survey. Twenty-five occupants participated in the field study. In this study, 83 measurements of physical environmental conditions were cross-linked with participants' window blind controlling preferences. A total of 13 predictive window blind control bivariate and multivariate logistic models were derived. As hypothesised, the probability of a window blind closing event increased as the magnitude of physical environmental and confounding factors increased (p 5 0.01). The main predictors were window/background luminance level and vertical solar radiation at the window. The confounding factors included MRT, direct solar penetration and participants' selfreported sensitivity to brightness. The results showed that the models correctly predict between 72-89% of the observed window blind control behaviour. This research extends the knowledge of how and why building occupants manually control window blinds in private offices, and provides results that can be directly implemented in energy simulation programs.

Occupants interaction with electric lighting and shading systems in real single-occupied offices: Results from a monitoring campaign

“…In the literature, the variables considered in the monitoring and assessment of the occupants' control patterns are, typically: workplane (daylight) illuminance (Hunt 1979); average window luminance (Sutter, Dumortier et al 2006); maximum window luminance and background luminance (Inkarojrit 2008); DGI (Lee and Selkowitz 1995); DGP (Wienold and Christoffersen 2006); vertical transmitted direct solar radiation (Inoue, Kawase et al 1988); vertical incident global solar radiation (Foster and Oreszczyn 2001); and, duration of occupation/absence (Pigg, Eilers et al 1996;Mahdavi and Proglhof 2009). In the present study, it was decided that all parameters would be monitored so as to later assess to what extent the observed behaviour agrees with the behaviour suggested by each model.…”

“…The occupants' control patterns observed during the monitoring campaign were compared to four of the most cited behavioral models indicated in the literature: two related to the control of the electric lighting -Switch On probability (Hunt 1979) and Switch Off probability (Pigg, Eilers et al 1996) -and two related to the control of the shading systemsopening/closing shading algorithm (Haldi and Robinson 2009) and closing probability (Inkarojrit 2008). The predicted probability for an action (computed based on environmental conditions) was compared against the frequency with which such adjustment was observed during monitoring.…”

A library of building occupant behaviour models represented in a standardised schema

“…The way it is expressed in the model, blind closing behaviour is driven by indoor and outdoor air temperature. Inkarojrit's (Inkarojrit 2008) results showed that the frequency of window blind closing events increased as the luminance and vertical solar radiation levels (direct normal radiation) increased. He built multiple models based on longitudinal logistic regression using one to four input variables.…”

“…be able to represent more OB models in the schema, more Drivers and Systems should be added, and the definition of Needs should be broader to accept more types of models. Some researchers used mathematical formulas that have not yet been implemented in obXML, such as the logit function with four independent variables used by the M1 model of Inkarojrit (Inkarojrit 2008). Therefore, an equation editor should be developed to provide freedom for users.…”

GlareShade: a visual comfort-based approach to occupant-centric shading systems

“…Previous research investigate the operation of shading devices based on parameters such as vertical illuminance, irradiance, and window luminance levels (Reinhart and Voss 2003;Inkarojrit 2008;Lee et al 2005). Several metrics have been introduced over the past decade to evaluate glare from a given viewpoint.…”