Energy-saving performance of light shelves under the application of user-awareness technology and light-dimming control

Kim, Kyung-Soo; Lee, Heangwoo; Jang, Hyang-In; Park, Chang-Young; Choi, Cheol Woong

doi:10.1016/j.scs.2018.10.005

Cited by 30 publications

(32 citation statements)

References 40 publications

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“…Second, this study derived the lighting energy used in each case based on the lighting control derived above. However, to calculate the lighting energy, this study reflected 15 days in summer, 30 days in mid-season, and 15 days in winter, based on a related study [15], considering only one hour facing south for each day. The solar altitudes for summer, mid-season, and winter were set to 76.5, 53, and 29.5 • , respectively, based on the location of Seoul, South Korea.…”

Section: Performance Evaluation Methodsmentioning

confidence: 99%

“…However, conventional light shelves use flat reflectors to introduce external natural light into rooms [14], so the daylighting performance of the light shelf may be reduced depending on external environmental factors, such as the altitude of the sun. Recently, research [15,16] and technologies incorporating operating techniques have been introduced to solve this problem; however, moving light shelves may be unsuitable for saving building energy due to difficulties in maintenance and the need to consume additional energy in their operation [17]. This study proposes the use of prism sheets to solve these problems since they can improve daylighting performance when applied to light shelves by changing the propagation of light through reflection and refraction.…”

Section: Concept Of a Light Shelf And Summary Of Previous Studiesmentioning

confidence: 99%

“…Light shelves are classified into external and internal light shelves depending on the installation location [14]; external light shelves have better daylighting performance than internal light shelves [18], however, there are issues related to damage and maintenance since they are installed on the outside [17]. As shown in Table 1, recent studies related to light shelves [11][12][13][14][15][16][18][19][20][21] have applied advanced technologies such as user recognition and location recognition or have incorporated daylighting and shading systems to improve the daylighting performance. Although the light shelves proposed in and the surface of the ceiling.…”

Section: Concept Of a Light Shelf And Summary Of Previous Studiesmentioning

confidence: 99%

“…As shown in Table 1, recent studies related to light shelves [11][12][13][14][15][16][18][19][20][21] have applied advanced technologies such as user recognition and location recognition or have incorporated daylighting and shading systems to improve the daylighting performance. Although the light shelves proposed in Energies 2020, 13, 4618 3 of 13 these studies may contribute to saving lighting energy by maximizing the daylighting performance, they require complex structures or increase the range of motion and therefore have lower economic efficiency than simple conventional light shelves.…”

Section: Concept Of a Light Shelf And Summary Of Previous Studiesmentioning

confidence: 99%

“…Table 4 shows three cases according to how the prism sheet was applied, and the details of these cases are given as follows: Case 1 uses an external light shelf with no prism sheet applied, which is similar to conventional light shelves. The variables of the light shelf were set as shown in Table 5 based on related research [15], and the height of the light shelf was set to 1.8 m in consideration of the occupants' eye level to maintain window view. Case 2 uses a prism sheet attached to the glass surface of the window without installing a light shelf.…”

Section: Consideration Of Optimal Indoor Illumination Standards For Pmentioning

confidence: 99%

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Performance Evaluation of External Light Shelves by Applying a Prism Sheet

Lee

Seo

2020

Energies

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To address the increased use of lighting energy in the building sector, research on the use of light shelves has been increasing. Previous studies have focused on applying operating techniques to improve daylighting performance, which reduces the economic efficiency of light shelves and the building energy savings. This study proposes the use of prism sheets to improve the performance of light shelves, a concept which was validated by evaluating the performance related to saving building energy and improving indoor light uniformity through a full-scale testbed. This study used an external light shelf with no prism sheet, a window with a prism sheet applied, and a window with both an external light shelf and prism sheet applied as Case 1, Case 2, and Case 3, respectively, and analyzed the illuminance distribution and lighting energy consumption required to maintain the optimal indoor illumination for each case. This study also derived the optimal specifications for each case to save building energy and considered the flow of natural light to analyze the performance evaluation results. The main findings are as follows: (1) the optimal specifications to improve daylighting performance were derived for Case 1, requiring the application of operating techniques; (2) Case 2 was not suitable for saving energy and improving light uniformity when compared to Case 1; and (3) Case 3 was effective in saving building energy. In Case 3, even when the light shelf was fixed at 20° without moving, it saved building energy and improved light uniformity compared to Case 1. However, the prism sheet in Case 3 should be detached during winter to maximize building energy savings.

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Section: Performance Evaluation Methodsmentioning

confidence: 99%

Section: Concept Of a Light Shelf And Summary Of Previous Studiesmentioning

confidence: 99%

Section: Concept Of a Light Shelf And Summary Of Previous Studiesmentioning

confidence: 99%

Section: Concept Of a Light Shelf And Summary Of Previous Studiesmentioning

confidence: 99%

Section: Consideration Of Optimal Indoor Illumination Standards For Pmentioning

confidence: 99%

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Performance Evaluation of External Light Shelves by Applying a Prism Sheet

Lee

Seo

2020

Energies

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Reduzierung des Kunstlichteinsatzes durch Anpassung der Nachlaufzeit an individuelle Anwesenheitsmuster

et al. 2021

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Gegenwärtig sind präsenzgesteuerte Beleuchtungssysteme meist an konstante und relativ lange Ausschaltverzögerungen gekoppelt, um die Systemakzeptanz gegenüber fehlerhafter Abwesenheitsdetektion sicherzustellen. Die dabei zur Anwendung kommenden, generalisierten und für alle Arbeitsplätze und Gebäudenutzenden gleichen Abschaltzeiten werden meist bereits vor der Erstinbetriebnahme entschieden. Eine Berücksichtigung von Nutzerindividualitäten, welche durch Tätigkeitsprofil und Unternehmenskultur maßgeblich beeinflusst werden, bleibt dabei außen vor. Dabei nehmen Nutzerindividualitäten eine entscheidende Rolle bei der Umsetzung von Konzepten ein, die die energetische Systemperformanz steigern. Die im Folgenden vorgestellte Studie untersucht daher auf Basis von Belegungsdaten die Auswirkungen des Verhaltens von Gebäudenutzenden auf den Energiebedarf. Die identifizierten Anwesenheitsmuster dienen dazu, die Beleuchtungssteuerung auf individueller Ebene zuzuschneiden. Die Ergebnisse führen auf, dass eine signifikante Reduktion der Ausschaltverzögerung und des damit verbundenen Energiebedarfs ohne negative Auswirkungen auf Systemakzeptanzraten oder Nutzerkomfort möglich ist. Eine hohe räumliche Sensorauflösung erweist sich dabei jedoch als Ausgleich zu potenziell erhöhten Falsch‐Aus‐Raten als erforderlich. In diesem Zusammenhang wird die Bedeutung der Sensorpositionierung und ‐anzahl herausgestellt.

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