Examining the Impact of Daylighting and the Corresponding Lighting Controls to the Users of Office Buildings

Abstract

Daylight utilization significantly contributes to energy savings in office buildings. However, daylight integration requires careful design so as to include variations in daylight availability and maintain a balance between factors such as lighting quality and heat gain or loss. Designers with proper planning can not only improve the visual environment and create higher-quality spaces, but simultaneously minimize energy costs for buildings. The utilization of photosensors can exploit the benefits of daylighting by dimming the lighting system, so that no excessive luminous flux is produced, thus leading to energy savings as well as visual contentment. However, the human factor is crucial for the proper function of a lighting control system. Without its acceptance from the users, energy savings can be minimized or even negligible. The objective of this paper is to present a post-occupancy evaluation regarding occupant satisfaction and acceptance in relation to daylighting in offices equipped with automated daylight controls. In addition, the response of the users was compared with lighting measurements that were performed during the post-occupancy evaluation. Three case studies of office buildings with installed daylight-harvesting systems were examined. The age of the occupants was a crucial factor concerning their satisfaction in relation to the lighting levels. Aged users were more comfortable with lighting levels over 500lx, while young users were satisfied with 300lx. The impact of different control algorithms was outlined, with the integral reset algorithm performing poorly. The acceptance of the users for the closed loop systems maintained the expected energy savings of the daylight harvesting technique. Most of the occupants preferred to use daylight as a light source combined with artificial light but having the control to either override or switch it on and off at will. The results shown that a post-occupancy survey along with lighting measurements are significant for making an office environment a humancentric one.

Lighting Standards Revisited: Introduction of a Mathematical Model for the Assessment of the Impact of Illuminance on Visual Acuity

“…The recommended lighting standards should reflect the lighting conditions at which visual tasks can be conducted effectively and comfortably in an energyefficient way which complies with the mandate against light pollution. 13,17,[30][31][32][33][34] Within this context, our study evaluates whether current lighting standards address the needs both of pseudophakic and normophakic patients by exploring the impact of illuminance on visual acuity both theoretically and experimentally.…”

“…[12][13][14][15] Even the updated European norms (prEN 12464-1 2019) that are supposed to address the higher lighting needs of the seniors do not take into consideration the possible different characteristics of people that have artificial IOLs implanted. 16,17 Implantation of a multifocal IOL completely modifies light transmission to the retina. Since the accommodation of the eye is iatrogenically disrupted, the uniform light distribution within the eye is also disrupted.…”

The Interaction Effect of Occupant Behavior-Related Factors in Office Buildings Based on the DNAS Theory

“…Some previous research also aimed to reveal the associations and correlations among different occupant behaviors [63][64][65][66][67][68], and the results showed that interactions exist between different behaviors, and these interactions can provide detailed recommendations for building energy conservation. Therefore, a systematic and comprehensive exploration of occupant behavior-related factors can better explain the components of energy consumption and achieve better energy-saving effects.…”

„Skywatcher” System for Daylight Measurements

“…The sky models developed, with luminance distributions determined for them in the zenith of the LVZ sky, reflect the state of the sky for individual degrees of cloudiness and diffusion of particles in the atmosphere. [18][19][20][21][22][23][24][25][26][27][28][29][30] According to the calculation procedure proposed by the CIE [17], geographical coordinates and time zone in the examined location are determined, and then the position of the Sun in the sky on a given day and at a specific time is determined. The declination angle , which determines the angular position of the blue equator relative to the ecliptic, is related to the next day in year n: 284 23, 45 sin 360 365…”